MRI AND CT

Findings in CT and MRI

Computed Tomography - 1
CT: Head and Neck - 3
Neurocranium - 3
Pituitary - 10
Petrous pyramids - 13
Orbit - 17
Paranasal sinuses - 22
Cervical soft tissues - 26
CT: Chest - 31
Thoracic organs - 31
CT: Abdomen - 36
Upper abdominal organs - 36
Liver - 44
Pancreas - 50
Kidneys - 56
Adrenal glands - 61
Female pelvis - 64
Male pelvis - 68
CT: Spinal Column - 72
Cervical spine - 72
Thoracic spine - 76
Lumbar spine - 80
Magnetic Resonance Imaging - 85
MRI: Head and Neck - 87
Neurocranium - 87
Pituitary - 95
Internal auditory canals, petrous - 100
Orbit - 104
Paranasal sinuses - 108
Cervical soft tissues - 112
MRI: Chest - 118
Thoracic organs - 118
Breast - 125
VIMRI: Abdomen - 128
Upper abdominal organs - 134
Kidneys - 140
Adrenal glands - 145
Female pelvis - 150
Male pelvis - 155
Testes - 159
MRI: Spinal Column - 162
Cervical spine - 162
Thoracic spine - 168
Lumbar spine - 172
Sacroiliac joints - 178
MRI: Joints - 183
Temporomandibular joint - 183
Shoulder joint - 186
Elbow joint - 195
Hip joint - 200
Knee joint - 204
Ankle and subtalar joints - 211
MRI: Special Investigations - 217
Cranial vessels - 217
Cranial venous vessels - 220
MR angiography of the renal arteries 223
Pelvic and lower limb vessels - 227
MR cholangiopancreatography - 231
Cervical arteries - 234
References - 241

Computed Tomography

CT: Head and Neck

Neurocranium

The interhemispheric fissure is centered on the midline. The cerebrumand cerebellum show normal cortical sulcation.The cerebral ventricles are of normal size and symmetrically arranged.There are no signs of increased intracranial pressure.Normal development of the white matter and cortex, with normal den-sity of the periventricular white matter.The basal ganglia, internal capsule, corpus callosum, and thalamus ap-pear normal.The brain stem and cerebellum, if evaluable, also appear normal.Sella and pituitary are normal. Parasellar structures are unremarkable.There are no abnormalities in the cerebellopontine angle areas on bothsides.The paranasal sinuses and mastoid air cells are normally developed,clear, and pneumatized. The orbital contents are unremarkable. Thereare no abnormalities in the calvarium.

InterpretationNormal cranial CT
Interhemisphericfissure
Centered on the midline
No displacement
Falx cerebri
. Width
. Density (no calcifications)
Corticalsulcation Of cerebrum and cerebellum (arbor vitae):
Configuration
Number of sulci
Width of sulci
No coarsening of sulci
No circumscribed narrowing or expansion
Well-defined cisterns and cortical

CT: Head and Neck

Cerebral cortex
Width Distribution (no ectopic tissue
Density no calcifications or hemorrhages
No separation from the calvarium
No abnormal fluid collection (convex or concave)between
the cerebral cortex and calvarium
Ventricles
Shape
Size appropriate for age (see below)
Symmetry (no unilateral or circumscribed en-largement
No signs of increased intracranial pressure
White Matter Density
No hypodensities (circumscribed, lacunar, or dif-fuse
No hyperdense changes (calcification, hemor-rhage
Normal width in relation to cortexBasal ganglia,
Positioninternal and
Sizeexternal capsule,
Delineationthalamus
DensityCorpus callosum
Configuration! Size
DensityBrain stem
Shape
Density (homogeneous)
No focal abnormalitiesCerebellum
General form (symmetry)
Cortex (width, sulcation)
White matter (homogeneous density)Intracranial
Coursevessels
Width
No abnormal dilatation
No vascular malformations Sella and
Size pituitary
Configuration Density
Borders
Parasellar structures
Cerebellopontine angle area
Width and symmetry of bony portions of in-ternal auditory canals
CSF spaces symmetrical and of normal size,no masses
Mastoid air cells, mastoid antrum
Anatomy
Pneumatization
Borders (wall thickness, smooth contourswith no discontinuities
No masses
No fluid-dense opacification
Cochlea and semicircular canals
Anatomy
Configuration
Smooth bordersParanasal
Pneumatization
Borders (wall thickness, smooth and continuouscontours
Nasal cavity
Pneumatization
Septum on midline
Turbinates (presence of superior, middle, andinferior turbinates; width)
Orbit
Configuration of orbital cone
Globe (position—see below; size, density,wall thickness
Eye muscles (position, course, density, width
Optic nerve (course, width—see below
Ophthalmic vein (course, width—see below)
Calvarium
Configuration
Contours (smooth, sharp, no expansion or bonyoutgrowths, no osteolytic or osteoplastic areas)

White matter Cortex
Noncontrast: 39 HU 32 HU! Postcontrast: 41 HU 33 HU(Each value has a deviation of ± 2 HU [Hounsfield units].)Attenuation difference between cortex and white matter: ap-proximately 7 HUVentricular dimensions1 Cella media index:! B/A > 4 = normal2 Frontal horn of lateral ventricle (at level of foramen ofMonro):! Under age 40: Tympanic cavity
Anatomy Shape Borders Pneumatization Auditory ossicles (malleus, incus, stapes: pre-sence, shape, relative positions in ossicularchain)Mastoid ! Cellular anatomy (antrum, retrofacial cells, peri-tubal cells, peribulbar cells, marginal cells, ter-minal cells Cells small, large, or of mixed sizes; normal uniform enlargement of cells from antrum toterminal cells Pneumatization Borders (septal thickness, smooth contourswith no discontinuities No masses Not opacified by abnormal fluid or soft-tissuedensityCerebellopontine ! Brain stemangle area Shape Density (homogeneous No focal abnormalities Vestibulocochlear and facial nerve nuclei. No hypodensity No masses! Entry sites of vestibulocochlear nerve (enterspons and medulla at lateral extension of medul-lopontine sulcus) and facial nerve Bilaterally symmetrical! CSF spaces Cerebellopontine angle cistern (symmetrical,fluid density No masses Well delineated— No vascular loop! External auditory canals Anatomy Course Width Borders. Petrous PyramidsRest ofneurocranium! Cerebrum (especially the temporal lobe) andcerebellum Configuration Sulcation Cortical markings (arbor vitae) well defined Width of sulci No circumscribed widening or narrowing Homogeneous density of cortex and whitematter (no hypodense or hyperdensechanges)CSF spaces ! Prepontine cistern! Fourth ventricleImportant Data1 Internal auditory canal:! Approx. 5 10 mm, with ca. 1 mm difference between theright and left sidesAxial scan through the internal auditory canal CT: Head and NeckAxial scan for evaluating the auditory ossiclesCoronal scan through the internal auditory canal. orbits are symmetrical and of normal size, with normal develop-ment of the orbital cone. The configuration of the smooth, sharply de-fined orbital walls is normal. There are no foci of bone destruction andthere is no circumscribed widening of bony or soft-tissue componentsof the orbital walls.The globes are symmetrical and show normal size and position. Theocular contents are of normal density. The ocular wall is smooth,sharply defined, and of normal thickness.

The optic nerve shows a nor-mal course and caliber on each side.The eyemuscles are normally positioned and display normal width andcourse. The retrobulbar fat and ophthalmic vein are unremarkable.Imaged portions of the neurocranium and paranasal sinuses show noabnormalities.InterpretationThe orbit and its contents appear normal.ChecklistOrbits ! Symmetrical! Normal size! Normal orbital coneOrbital walls ! Smooth, sharp borders! No bone destruction! No circumscribed widening of bone or soft-tissue componentsGlobe ! Position (see below)! Symmetry Size (see below SphericalOcular DensityOcular Borders (smooth and sharp Uniform thicknessOptic nerve Normal caliber (see below CourseEye muscles Position Width (see below CourseRetrobulbar fat Clear No masses.

Ophthalmic vein
Course Caliber (see below)Lacrimal gland Size Symmetry unilateral or bilateral enlargement Position No excavation or destruction of adjacent bone Homogeneous internal structure No hypodense areas Smooth bordersNeurocranium Temporal lobes Frontal Maxillary Ethmoid cellsAxial scan plane Right: 28.6 ± 1.2 mm Left: 29.4 ± 1.4 mm Sagittal plane (reconstruction Right: 27.8 ± 1.2 mm Left: 28.2 ± 1.2 mm2 Position of globe Posterior margin is 9.9 mm ± 1.7 mm behind the interzygo-matic line3 Optic nerve (axial plane):a Retrobulbar segment: 5.5 mm ± 0.8 mmb Narrowest point (at approxinately mid-orbit): 4.2 mm ±0.6 mm4 Ophthalmic vein:! 1.8 mm ± 0.5 mm (axial plane, 4 mm slice thickness)! 2.7 mm ± 1 mm (coronal plane)5 Eye musclesa Superior rectus: 3.8 mm ± 0.7 mmb Oblique: 2.4 mm ± 0.4 mmc Lateral rectus: 2.9 mm ± 0.6 mmd Medial rectus: 4.1 mm ± 0.5 mme Inferior rectus: 4.9 mm ± 0.8 mmLacrimal gland: less than half of the gland is anterior to the fron-tozygomatic process.

Paranasal Sinuses

The frontal sinuses are normally developed, clear and pneumatizedwith smooth wall contours.The ethmoid cells have a normal appearance and intact bony walls,especially on the orbital side. There are no areas of wall erosion or mu-cosal thickening.The sphenoid sinus is normally developed and has a coarse honeycombstructure. There are no fluid collections or mucosal swelling.The maxillary sinuses are bilaterally symmetrical and have smoothwalls of normal thickness. The sinuses are clear and aerated with nobone destruction. The nasal septum is on the midline, and the turbi-nates are normally developed.The nasal cavity, pharynx, and imaged parapharyngeal structures showno abnormalities.InterpretationThe paranasal sinuses appear normal. Paranasal SinusesChecklistFrontal sinuses Anatomy Wall contours (smooth PneumatizationEthmoid cells Anatomy Pneumatization Bony structures (especially bordering the orbit:boundaries are smooth, sharp, and intact No wall erosions No mucosal thickening Sphenoid sinus Anatomy (coarse honeycomb structure Clear and pneumatized No fluid collection! No mucosal swelling! Bony structures (smooth, intact walls, no ero-sion)! No extrinsic wall Anatomysinuses Size (bilaterally symmetrical Bony structures (smooth, intact contours, wallsof normal width, no bone erosion or destruction)! Pneumatization! No tooth roots projecting through maxillarysinus floorNasal Anatomy (symmetry Size Aeration (clear Nasal septum on the midline! Nasal turbinates (three on each side: superior,middle, inferior) are normally developedPharynx and ! Anatomy (symmetry)parapharyngeal ! Sizestructures ! Wall thickness! No foreign bodies, calcifications, or masses aranasal SinusesImportant Data1 Frontal sinus:! Height ca. 1.5!2 cm2 Sphenoid sinus:! Width 0.9!1.4 cm3 Maxillary sinuses:a Width ca. 2 cmb Height ca. 2 cmAxial scanAxial scan

Visceral spaceAnterior cer-vical spaceCarotid spacePerivertebralspace (pre-vertebralportion)SuperficialspaceRetropharyn-geal spacePosteriorcervical spacePerivertebralspace(paraspinalportion)CT: Head and NeckCervical Soft TissuesThe cervical soft tissues show normal configuration, and the cervicalspine is normally positioned. The oral floor muscles are bilaterally symmetrical and normallydeveloped. The spaces of the oral floor and neck are clear and well de-fined.Imaged portions of the parotid and submandibular glands show no ab-normalities.The pharynx and larynx show normal boundaries and normal wallthickness.The thyroid gland shows reasonable symmetry and normal size. Thethyroid lobes have a normal internal structure.Cervical vessels that can be evaluated with CT have a normal appear-ance.The muscular structures of the neck appear normal, and there are nosigns of cervical lymphadenopathy.Interpretation The cervical soft tissues appear normal. Cervical Soft TissuesChecklistCervical soft ! Configurationtissues ! Normal anatomy! Normal position of cervical spineOral floor ! Anatomymuscles ! Width! Bilateral symmetry! Boundary definition! Internal structure! Spaces of oral floor are clearly definedSubmandibular ! Size (symmetry)gland (and ! Densityparotid gland) ! No dilatation of glandular duct! No hypodense or hyperdense areas within theglandular tissuePharynx and ! Shape (symmetrical)larynx ! Size! Smooth walls! Normal wall thickness! No massesCervical spaces ! Retropharyngeal space! Parapharyngeal space (visceral space)! Carotid space! Anterior and posterior cervical spaces! Perivertebral space (prevertebral and paraspinalportions Configuration Boundaries Symmetry Internal structure Width (see below)Esophagus ! Position! Wall thickness (see below)! Boundaries! No massesThyroid gland ! Anatomy (two lobes, largely symmetrical)! Size (see below)! Internal structure (homogeneous)! No cysts! No nodules! No calcifications

Vertebral bodies(if evaluable) Number Shape Position Contours! Intervertebral disk spaces! Spinal canal Width No circumscribed narrowing! Normal width of cervical spinal cord! No masses! No narrowing Cervical Soft TissuesImportant DataPrevertebral soft tissues1 Retropharyngeal: ca. 1.7 ± 0.7 mm2 Retroglottic: ca. 6.0 ± 1.1 mm3 Retrotracheal: ca. 8.4 ± 2.5 mmLumina of upper respiratory tract (normal respiration):4 Laryngeal inlet (hyoid level): ca. 19 ± 4 mm5 Glottis: ca. 21 ± 4 mm6 Trachea: ca. 17 ± 3 mm7 Thyroid dimensions:a Length: 3.6!6 cm (reconstruction)b Width: 1.5!2 cmc Depth: 1!2 cmVascular calibers (at level of thyroid gland)8 Common carotid artery: 6!10 mm9 Esophagus: wall thickness 3 mm.


CT: Chest

Thoracic OrgansBoth lungs are normally aerated and are applied to the chest wall on allsides. There is no sign of circumscribed pleural thickening and no fluidcollection.Pulmonary structure is normal and shows normal vascular markings.There are no intrapulmonary nodules or patchy opacities.Themediastinumis centered and of normal width. There is no evidenceof masses in the anterior, central, or posterior compartments.The hilar region on each side is unremarkable, and themain bronchi ap-pear normal.The heart is orthotopic with normal configuration. The cardiac cham-bers are of normal size.Major intrathoracic vessels and imaged portions of the supra-aortic ves-sels are unremarkable.The thoracic skeleton and thoracic soft tissues show no abnormalities.InterpretationThe thoracic organs appear normal at CT.ChecklistLungs ! Anatomy (paired and symmetrical)! Fully apposed to the chest wall! No pleural thickening! No wall thickening! No fluid collection (patchy or circumscribed)! Complete aeration! Normal attenuation values of lung parenchyma(see below)! Pulmonary structure! Vascular markings (diminish from center to pe-riphery)! No pulmonary nodules! No patchy opacities (e.g., plaques or infiltrates)Moeller, Normal Findings in CT and MRI © 2000 ThiemeAll rights reserved. Usage subject to terms and conditions of license.32blubberbluCT: ThoraxMediastinum ! Configuration, position Centered Width No masses in the anterior, central, or poste-rior compartment! Hilar region No masses or lymphadenopathy! Main bronchi Anatomy Course Width (see below)! Heart Position (centered slightly left of midline Configuration Size (cardiac chambers Myocardium (width—see below)Vessels ! Intrathoracic vessels (ascending aorta, aorticarch, descending aorta, vena cava Anatomy Size! Supra-aortic vessels (subclavian artery, brachio-cephalic trunk, left common carotid artery Anatomy SizeDiaphragm ! Shape (no contour abnormalities, costophrenicangle is sharp and clear)! Position (approximately the level of the 10th!11th posterior rib)! Width (no circumscribed widening, no defect)Thoracic skeleton ! Position(ribs, clavicle, ! Structuresternum, scapula)! Contours and symmetry! No bony expansion or destruction! Thoracic spine Position Shape of thoracic vertebraeThoracic soft ! Configurationtissues ! Width! Symmetry! Density. Thoracic OrgansImportant Data1 CT density of lung parenchyma:! -403 ± 25 HU2 Diameter of aorta:! < diameters =" 1.5:13" septum =" 38°Moeller," l =" between"> 5 cm is suspicious for hy-drops)b Width of gallbladder wall:! 1!3 mmc Width of common bile duct:! ! 8 mm (after cholecystectomy: ! 10 mm)6 Inferior vena cava:! Transverse diameter up to 2.5 cm7 Abdominal aorta:! Transverse diameter ca. 18!30 mm8 Kidneys:a Anteroposterior diameter ca. 4 cmb Transverse diameter 5!6 cm; craniocaudal diameter(= highest to lowest section) 8!13 cmc Transverse renal axis: posteriorly divergent angle of 120°d Width of renal cortex: 4!5 mme Width of ureter: 4!7 mmPosition of superior poles of kidneys:! Right: superior border of L1! Left: inferior border of T12Moeller, Normal Findings in CT and MRI © 2000 ThiemeAll rights reserved. Usage subject to terms and conditions of license.40blubberblu1a2a2bCT: AbdomenTime to corticomedullary equilibrium:! 1 minuteContrast excretion into the pyelocaliceal system:! 3 minutesGerota fascia (thickness):! 1!2 mmLymph nodes larger than 1 cm are suspicious for pathology.Attenuation values:! Liver: 65 ± 10 HU! Spleen: 45 ± 5 HU! Pancreas: 40 ± 10 HU! Fat: -65 to -100 HU! Kidneys: 30!45 HU without contrast medium; renal cortexafter contrast medium: approx. 140 HU! Adrenal glands: 25!40 HU without contrast medium! Muscle: 45 ± 5 HU! Blood vessels: approx. 40!55 HU without contrast medium! Gallbladder contents: 0!25 HU

AbdomenLiver

The liver is orthotopic and of normal size,with smooth borders and nor-mal attenuation values. It presents a normal internal structure with nofocal abnormalities.The intrahepatic and extrahepatic bile ducts are normal in their course,width, and contents.The gallbladder appears normal, presenting smooth borders and homo-geneous contents.The porta hepatis shows no abnormalities.Other visualized upper abdominal organs are unremarkable.InterpretationThe liver appears normal at CT. LiverChecklistLiver ! Position:— Directly below the right hemidiaphragm! Size Borders Smooth Sharp! Attenuation values Homogeneous internal parenchymal structure,no focal abnormalities! Intrahepatic bile ducts Course Width (general rule: ducts should no longerbe visible after contrast administration No calculi No air! Extrahepatic bile ducts Course (from porta hepatis to head of pan-creas Width Contents of homogeneous fluid density No calculi No air! Gallbladder Size Contours (smooth and sharp Wall thickness No pericholecystic fluid! Gallbladder Homogeneous Fluid density No calculi (hypodense or hyperdense No air Porta hepatis occupied by the hepatic artery,common bile duct, and portal vein; nomassesor lymphadenopathy Costophrenic sinus clear and aerated on bothsides; no pleural effusion, no infiltrates, nomasses

AbdomenSpleen ! Position! Configuration! Size Density (homogeneous internal structure)! Contours (smooth)Pancreas ! Position! Configuration! Size! Density (homogeneous internal structure)! Contours (smooth, lobulated)! Pancreatic duct! Para-aortic region unremarkableAdrenal glands, ! Positionkidneys (if ! Size Internal structureAbdominal cavity ! Intestinal structures (if visualized and evaluable:configuration, width, wall thickness)! No free extraintestinal or intra-abdominal air orfluidSoft tissuesImportant DataDimensions1 Liver:a Angle of left hepatic border: ca. 45°b Caudate lobe/right lobe (CL/RL) = 0.37 ± 0.16 (e.g., 0.88 ± 0.2in cirrhosis. Reference lines [from medial side]: line I is tan-gent to themedial border of the caudate lobe; line II is paral-lel to I and tangent to the lateral aspect of the portal vein;line III is tangent to the lateral hepatic border and perpen-dicular to a line midway between the portal vein and infe-rior vena cava and perpendicular to I and II.c Left lobe (anteroposterior diameter measured on the para-vertebral line): up to 5 cm2 Portal vein:! Up to 1.5 cm3 Hepatic veins:! Up to 0.5 cmMoeller, Normal Findings in CT and MRI © 2000 ThiemeAll rights reserved. Usage subject to terms and conditions of license.47bberLiver4 Gallbladder:! Horizontal diameter up to 5 cm (> 5 cm is suspicious for hy-drops)5 Width of gallbladder wall:! 1!3 mm6 Width of common bile duct:! ! 8 mm (after cholecystectomy: ! 10 mm)Spleen:! Depth (D): 4!6 cm! Width (W): 7!10 cm! Length (L): 11!15 cm! Splenic index: D"W"L = 160!440Kidneys:! Craniocaudal diameter: 8!13 cm! Anteroposterior diameter: ca. 4 cm! Transverse diameter 5!6 cmPosition of superior poles:! Right: superior border of L1! Left: inferior border of T12Width of renal cortex:! 4!5 mmGerota fascia (thickness):! 1!2 mmAdrenal glands (variable):! Crural thickness <> 5 cm issuspicious for hydrops)! Width of gallbladder wall: 1!3 mm! Gerota fascia (thickness): 1!2 mm! Diameter of abdominal aorta: approx. 18!30 mm! Lymph nodes larger than 1 cm are suspicious forpathology. Abdomen Kidneys Both kidneys appear normal in size and position, with normal widthand density of the renal parenchyma. There is no evidence of a mass.The calices are of normal shape. The renal pelvis is normal and free ofstones, and there is no obstruction of urinary drainage. Contrast-enhanced scans showa normal time to corticomedullary equi-libriumand timely, symmetrical contrast excretion into the renal pelveswith no filling defects.The perirenal and pararenal spaces are unremarkable. Other visualized upper abdominal organs, especially the adrenal glands,show no abnormalities.InterpretationBoth kidneys appear normal. Kidneys Paired Position Size Organ Smooth and sharp Width of parenchyma! Density Normal relation of cortex to medulla! Renal pelves Structure and shape of caliceal groups Bilateral symmetry No expansion! Ureters One per side Course No obstruction! Peri- and pararenal spaces Fat attenuation No masses No increase in soft-tissue structures No fluid Kidneys! Peri- and pararenal fasciaeCourse— Width (no diffuse or circumscribed thicken-ing)Adrenal glands ! Shape! Size Slender crura! No circumscribed expansion Retroperitoneal space! No mass, fluid, or increased densityIntestinalstructures! Colon haustrations, small bowel! Wall thickness! Homogeneous contrast enhancement! No free extraintestinal or intra-abdominal air orfluidVessels ! Course! Size No lymphadenopathy Soft tissues ! Density! Symmetry! Muscles (size, internal structure, borders)! Fat (density, no soft-tissue or fluid infiltration)

CT: Abdomen

Important Data1 Distance between renal poles:! Superior poles: ca. 10 cm (4!16 cm) apart! Inferior poles: ca. 13 cm (9!18.5 cm) apart2 Transverse renal axis:! Posteriorly divergent angle of 120°3 Transverse renal diameter at level of hilum:! 5!6 cm (a, transverse) x 3!4 cm (b, anteroposterior)4 Width of cortex:! 4!5 mm5 Width of ureter:! 4!7 mm6 Gerota fascia (thickness):! 1!2 mmPosition of superior poles of kidneys:! Right: superior border of L1! Left: inferior border of T12 (variable; note that the differ-ence does not exceed 1.5 vertebral body heights)Renal dimensions:! Craniocaudal (= highest to lowest section!) 8!13 cmRight!left disparity in renal sizes:! Craniocaudal 1 cm)stationsPelvic skeleton ! Configuration! Margins (cortex smooth and sharp with no dis-continuities)! Bony structures! No circumscribed hypo- or hyperdense areas! Femoral heads are rounded and centered inacetabula! Sacroiliac joints are smooth and of normal width! Symphysis pubis Subcutaneous ! Densitytissue and ! Extentmuscles ! Borders! Symmetry CT: Abdomen Important Data1 Sacroiliac joint spaces:! Cartilage thickness 2!5 mm(anterior and inferior: 2!3 mm)2 Uterus:! Size (variable): Prepubescent: length up to 3 cm, transversediameter ca. 1 cm! Nullipara: length up to 8 cm, transverse diameter ca. 4 cm! Multipara: length up to 9.5 cm, transverse diameter ca.5.5 cm! Postmenopausal: length up to 6 cm, transverse diameter ca.2 cma Transverse diameter of upright uterus (= well-distendedbladder) ! 5 cmb Uterine cervix: transverse diameter ! 3 cm Female Pelvis3 OvariesPrepubescence: a, length up to 2.5 cm; b, transverse diame-ter ca. 2.5 cm! Sexual maturity: a, length up to 4 cm; b, transverse diame-ter ca. 2.5 cm! Postmenopausal: a, length up to 3 cm; b, transverse diame-ter ca. 1.5 cm4 Urinary bladder:! Wall thickness (of well-distended bladder): ca. 3 mm5 Rectum:! Wall thickness ! 5 mm6 Symphysis pubis:! Width < c7 =" 14"> 20!21 mm4 Width of spinal cord:! > 6!7 mm in sagittal plane

CT: Spinal Column

Thoracic SpineThe thoracic spine shows a normal degree of kyphosis in the lateral sur-vey scan, with no segmental malalignment.The vertebral bodies show normal shape and trabecular structure. Thecortical margins are of normal thickness and are free of osteophytes.The bony spinal canal has normal sagittal diameter.The intervertebral disks show normal CT density and normal posteriorconcavity. The disks do not project past the posterior surface of thevertebral bodies. The spinal cord is centrally placed and of normalwidth. It has homogeneous density and shows no circumscribed nar-rowing or expansion.The nerve roots show a normal course and passage through the neuro-foramina, which are of normal size and structure. The costovertebraland costotransverse joints are unremarkable.The prevertebral and paravertebral soft tissues show no abnormalities.InterpretationThe examined segments of the thoracic spine appear normal.ChecklistPosition ! Thoracic kyphosis! No segmental malalignment (lateral surveyscan)Bony spinal ! Width (see below)canal ! ShapeVertebral bodies ! Shape! Cortex (thickness, margins: smooth, sharp)! No marginal osteophytes! Trabeculae (uniform honeycomb arrangement,no rarefaction or circumscribed voids, no nar-rowing or expansion)Intervertebral ! Width disk space ! Margins (smooth, sharp)! Straight posterior disk contour! No disk protrusion past posterior surface ofvertebral bodiesSpinal cord ! Position (central)! Width! No circumscribed narrowing or expansion! Density (homogeneous) Thoracic Spine! Perimedullary thecal space clear: no encroach-ment from the anterior side (e.g., by an inter-vertebral disk or osteophyte) or posterior side(e.g., by a hypertrophic ligamentum flavum)Neuroforamina ! Configuration! Width! No encroachment from the anterior side (e.g., byan intervertebral disk or osteophyte) or posteriorside (e.g., by hypertrophic spondylarthrosis)Nerve roots ! Course and passage through the neuroforamina! No circumscribed expansionFacet joints ! Shape, symmetry! Pars interarticularis! Vertebral arches intact! Spinous processes (shape, length, bony struc-ture)! Costotransverse joints! Costovertebral joints (no hypertrophy)! RibsSoft tissues ! Symmetrical arrangement on both sides of thevertebral bodies and spinous processes! No masses! Prevertebral soft-tissue structures (especiallythe lungs, heart, and aorta) CT: Spinal ColumnImportant Data1 Width of spinal canal:! Transverse diameter at level of pedicles > 20!21 mm2 Sagittal diameter:! T1!T11 = 13!14 mm, T12 = 15 mm3 Jones-Thomson ratio (= A!B/C!D):! Between 0.5 and 0.22 = normal (< 22 =" spinal"> 20!21 mm, L5 > 24 mm4 Sagittal diameter:! 16!18 mm (simple formula: not less than 15 mm; 11!15 mm = relative stenosis, less than 10 mm = absolute ste-nosis)5 Jones-Thomson ratio (= A!B/C!D):! Between 0.5 and 0.22 = normal (<0.22> 4!5 mm7 Ligamenta flava:! Width <> 4 = normal2 Frontal horn of lateral ventricle (at level of foramen ofMonro):! Under 40 years: < datach =" Chamberlain’s" diameters =" 1.5:14" septum =" 38°"> 5 cm is suspicious for hy-drops)b Width of gallbladder wall: 1!3 mm3 Width of common bile duct:! ! 8 mm (! 10 mm after cholecystectomy)4 Spleen:a Depth: 4!6 cmb Width: 7!10 cmc Length: 11!15 cmSplenic index: D"W" L = 160!440Axial image

MRI: Abdomen

Pancreas
Head: up to 3.5 cmb
Body: up to 2.5 cmc
Tail: up to 2.5 cm

Pancreatic duct: width 1!3 mm6 Adrenal glands (variable):! Crural thickness <> 5 cm is suspicious for hy-drops)b Width of gallbladder wall: 1!3 mm3 Width of common bile duct:! ! 8 mm (after cholecystectomy: ! 10 mm)T1-weighted noncontrast axial image LiverT2-weighted noncontrast axial imageT1-weighted axial image after the i. v. administration of asuperparamagnetic contrast agentT2-weighted axial image after the i. v. administration of asuperparamagnetic contrast agent MRI: Abdomen1d1c1b4 Portal vein:! Up to 1.5 cm5 Hepatic veins:! Up to 0.5 cmSpleen:! Depth D): 4!6 cm! Widt(W): 7!10 cm! Length (L): 11!15 cm! Splenic index: DxWxL = between 160 and 440Adrenal glands (variable):! Crural thickness < b ="transverse)" c =" anteroposterior)6"> 12 cm3 Pelvic outlet:! Approximately 9 cm4 Transverse diameter (transverse interspinous distance):! Approximately 13 cm5 Uterus (variable):! Prepubescent: a, length up to 3 cm; b, transverse diameterca. 1 cm! Nullipara: a, length up to 8 cm; b, transverse diameter ca.4 cm! Multipara: a, length up to 9.5 cm; b, transverse diameter ca.5.5 cm! Postmenopausal: a, length up to 6 cm; b, transverse diame-ter ca. 2 cm(Transverse diameter of upright uterus = well distended blad-der ! 5 cm)6 Uterine cervix:a Craniocaudal ! 2 cmb Transverse diameter ! 3 cmMidsagittal image through thelower abdomen.Moeller, Normal Findings in CT and MRI © 2000 ThiemeAll rights reserved. Usage subject to terms and conditions of license.153blubberblzubber4 110117b5bFemale PelvisParacoronal image along the true conjugate (line 1 in Fig.on left [= midsagittal section through the lower abdo-men]).Coronal image

MRI: Ovaries

Prepubescent: a, length up to 2.5 cm;
b, transverse diame-ter ca. 2.5 cm!
Sexualmaturity: a, length up to 4 cm;
b, transverse diame-ter ca. 2.5 cm!
Postmenopausal: a, length up to 3 cm;
b, transversediameter ca. 1.5 cm8
Urinary bladder (well distended
Wall thickness ca. 3 cm9 Rectum:! Wall thickness ! 5 mm10 Symphysis pubis:! Width < open =" normal7"> 6!7 mm6 Sagittal diameter:! C1 ! 21 mm! C2 ! 20 mm! C3 ! 17 mm! C4!C7 = 14 mm7 Height of intervertebral disk spaces:! C2 <> 20!21 mmMoeller, Normal Findings in CT and MRI © 2000 ThiemeAll rights reserved. Usage subject to terms and conditions of license.165blubberblzubber1a4735682Cervical SpineT2-weighted midsagittal imageT2-weighted sagittal image.


MRI: Spinal Column

Coronal imageAxial image at the level of the dens Cervical SpineAxial image at the level of the densAxial image at the level of the laminae MRI: Spinal ColumnThoracic SpineThe thoracic spine shows a normal degree of kyphosis with a normalwidth of the bony spinal canal.The vertebral bodies are normal in their number, shape, and interrela-tionships. The articulating vertebral end plates present smooth mar-gins. The intervertebral disk spaces are of normal height, and the disksdo not project past the posterior surface of the vertebral bodies in anysegment.The spinal cord displays normal course, configuration, width, and inter-nal structure.The bone marrow of the vertebral bodies appears normal.The prevertebral and paravertebral soft tissues show no abnormalities.InterpretationThe thoracic spine appears normal.ChecklistPosition ! Thoracic kyphosis No segmental malalignmentBony spinal canal ! Width (see below)! Smooth marginsVertebral bodies ! Number (12)! Shape (square)! Position (straight alignment of posterior mar-gins, no step)! End plates— Continuous margins— No circumscribed depression— Smooth contours, no marginal osteophytesIntervertebral ! Width disk space ! Normal signal characteristics: moderate toslightly hyperintense T2-weighted signal inten-sity (not hypointense to other disks); “nuclearcleft” signifies an adult disk! No disk protrusion past posterior surface of adja-cent vertebral bodiesSpinal cord ! Configuration! Width! Signal characteristics Thoracic Spine! No circumscribed signal changes! No circumscribed narrowing or expansionNerve roots ! Course! Passage through the neuroforaminaDural sack ! Shape! Width! No circumscribed narrowing or expansion! Contents of fluid intensityNeuroforamina ! Configuration! WidthFacet joints ! Shape! Position! Contours (smooth, continuous)! No hypertrophy! Vertebral arches intact! Pars interarticularis intact! No cleft anomalies! No shortening of pediclesSpinous ! Shapeprocesses ! Position! Size! Bony structure! Fat-equivalent signal intensity of bone marrow! No circumscribed hypointense or hyperintenseareasSoft tissues ! Symmetrically arranged on both sides of thevertebral bodies and spinous processes! No massesAorta ! Prevertebral soft-tissue structures MRI: Spinal
ColumnImportant Data1 Kyphotic angle (of Stagnara):! Angle formed by a line parallel to the vertebral end plates ofT3 and T11 = 25°Width of spinal canal:2 Transverse diameter at level of pedicles:! > 20!21 mm3 Sagittal diameter:! T1!T11 = 13!14 mm! T12 = 15 mm4 Width of intervertebral disk spaces:! Smallest at T1! T6!T11: ca. 4!5 mm! Largest at T11!T12T2-weighted midsagittal image. Thoracic SpineAxial image at the level of the laminaeCoronal image MRI: Spinal ColumnLumbar SpineThe lumbar spine shows a smooth lordotic curve with a normal prom-ontory angle. The bony spinal canal displays normal width.The vertebral bodies are normal in their number, shape, and interrela-tionships. The articulating vertebral end plates present smooth mar-gins. The intervertebral disk spaces are of normal height, and the disksdo not project past the posterior surface of the vertebral bodies in anysegment.The conus medullaris terminates normally at the L1 level and dividesinto its filaments.The dural tube appears normal in its lumbar portion and evaluablesacral portion.The bone marrow of the vertebral bodies appears normal.The imaged soft tissues show no abnormalities.InterpretationThe lumbar spine appears normal.ChecklistPosition ! Lumbar lordosis Lumbosacral angle No segmental malalignmentBony spinal ! Width canal ! Smooth marginsVertebral bodies ! Number (five)! Shape (square)! Position (straight alignment of posterior mar-gins, no step)! End plates— Continuous margins— No circumscribed depression— Smooth contours— No marginal osteophytesIntervertebral ! Width disk space ! Normal signal characteristics: moderate toslightly hyperintense T2-weighted signal inten-sity (not hypointense to other disks); “nuclearcleft” signifies an adult disk Lumbar Spine No disk protrusion past posterior surface of adja-cent vertebral bodies (posterior disk contours onaxial images: concave at L1!L4, straight at L4/5,slightly convex at L5/S1)Conus medullaris ! Configuration! Width! No circumscribed narrowing or expansion! Position (terminates at approximately the L1level)! Normal division into filaments! Signal characteristics! Filaments:— Course (sweeping, not straight; no posterioradhesions)— Width— No circumscribed massNerve roots ! Course! Passage through neuroforamina! Dural sac:— Shape— Width— No circumscribed narrowing or expansion— Contents of fluid intensityBony portions of ! Neuroforamina:vertebral bodies — Configuration— Width! Facet joints:— Shape— Position— Contours (smooth, continuous)— No hypertrophy of facet joints! Vertebral arches intact! Pars interarticularis intact! No cleft anomalies— No shortening of pedicles— Spinous processes:— Shape— Position— Size— Bony structure! Fat-equivalent signal intensity of bone marrow— No circumscribed hypointense or hyper-intense areas MRI: Spinal ColumnSoft tissues ! Symmetrically arranged on both sides of thevertebral bodies and spinous processes! Prevertebral soft-tissue structures! No massesAorta, iliac vesselsImportant Data1 Width of intervertebral disk space and height of lumbar in-tervertebral disks:! 8!12 mm! Increases from L1 to L4/5! Usually decreases at L5/S1, but may be the same as orgreater than L4/52 Lordosis (static axis):! Plumb line from center of L3 should intersect S13 Lumbosacral angle (S1/horizontal plane) = 26!57°4 Width of spinal canal: sagittal diameter:! 16!18 mm (simple formula: not less than 15 mm; 11!15 mm = relative stenosis, less than 10 mm = absolute ste-nosis)5 Width of spinal canal: transverse diameter (at level ofpedicles):! L1!L4: > 20!21 mm! L5: > 24 mm6 Jones-Thomson ratio (= A!B/C!D):! Between 1/2 and 1/4.5 = normal (denominator > 4.5 = spinalstenosis)7 Lateral recess (sagittal diameter):! > 4!5 mm8 Ligamenta flava:! Width < fracture =" Hill-Sachs" complex =" posterior," complex =" medial"> 5 mm = ulnar shortening! < mm =" ulnar"> 8° MRI: Joints2 Congruence angle (formed by the bisector of the notch angleand a line connecting the patellar apex with the deepest pointof the notch):! 6° to -6°3 Notch angle:! 135!145° (average ca. 138°)4 Lateral displacement:! < patella ="0.8!1.2"> 1.2 = high-riding patella)7 Cartilage:a Patella: 3!4 ± 1 mmb Femoral condyles and tibial plateau: ca. 2.2 ± 0.6 mmAxial image 21/24.95% 5%3Knee JointAxial imageAxial image.
MRI: Joints
Anterior cruciate ligament:! Length: ca. 38 mm! Width: ca. 11 mma Angle formed by tangents to the tibial plateau and the ante-rior surface of the anterior cruciate ligament: 55°b Angle formed by Blumensaat’s line (dashed) and the ante-rior surface of the anterior cruciate ligament: 1.6°c Angle of posterior cruciate ligament: ca. 123° (abnormal atca. 106°)d Line of posterior cruciate ligament should intersect the dis-tal femur.Abnormal c and d are indirect signs of anterior cruciate liga-ment rupture.Posterior cruciate ligament:! Length: ca. 38 mm! Width: ca. 18 mmSagittal image at the level of the anterior cruciate Knee JointSagittal image at the level of the patellar ligament Sagittal image at the level of the posterior cruciate ligament MRI: JointsCoronal imageWiberg classification of patellar shapes (right knee). (From Möller, T.B.: Röntgennor-malbefunde. Thieme, Stuttgart 1996.) Ankle and Subtalar JointsAnkle and Subtalar JointsThe bones comprising the ankle joint show normal position and con-figuration, with normal development of the ankle mortise.The bonemarrow signal, trabecular pattern, and epiphyseal lines are allnormal.The joint space is of normal width. The cortex shows normal thicknessand smooth contours, especially along the tibial and talar articular sur-faces. There are no subchondral signal changes and no osteophytes.The lateral and medial ligaments are normal in their course, width, andsignal characteristics.The talocalcaneal and talonavicular joints appear normal. The interos-seous ligament between the talus and calcaneus is intact. The Achillestendon is normal in its course, width, and signal characteristics, and thepreachilles fat is clear. The tendons and plantar aponeurosis are unre-markable.The soft tissues show no abnormalities.InterpretationThe ankle joint and subtalar joint appear normal.ChecklistSkeleton ! Medial and lateral malleoli (ankle mortise),talus, calcaneus, tarsal bones:— Configuration— Position (shape, centering—see below)— Normal bone marrow signal— Epiphyseal plate closure after age 18— Normal trabecular patternArticular surfaces ! Congruence! Cortex:— Cortical thickness (uniform, no circumscribedexpansion)! Contours: smooth and sharp, no subchondralsignal changes (especially on the medial side =60% site of predilection for osteochondritis dis-secans), no discontinuities! Articular cartilage (if visible):— Thickness— Smooth surface.
MRI: JointsLigaments !
Lateral ligaments (in order of trauma frequency:anterior fibulotalar ligament, fibulocalcanealligament, posterior fibulotalar ligament):— Course (not wavy)— Signal intensity— Width— Smooth contours— Continuity— No periligamentous fluid! Medial (deltoid) ligament:— Course— Signal intensity— Width (see below)— Smooth contours— Continuity! Interosseous ligament:— Course— Continuity! Achilles tendon:— CourseWidth Shape (transverse oval cross section)— Signal characteristics— Continuity (especially 2!6 cm above the cal-caneal attachment = site of predilection fortears)— Normal-appearing preachilles fatSubtalar joint ! Configuration(talocalcaneal ! Positionjoint, talonavi- ! Width of joint spacecular joint)Soft tissues ! Tendons:— Flexor hallucis longus tendon is particularlyimportant (especially in the tarsal tunnel be-hind the medial malleolus, which is a site ofpredilection for tendinitis and rupture)— Tibialis posterior (its navicular attachment isa site of predilection for rupture)— Course— Signal intensity (uniformly hypointense, nocentral signal change)— Width— No discontinuities. Ankle and Subtalar Joints— Wall of tendon sheath (no fluid increase orwall thickening)! Plantar aponeurosis and calcaneonavicular liga-ment:— Shape— Width Hypointense in all MRI sequences— No circumscribed expansion or nodularity— No subcutaneous edema! Normal tarsal canal! Soft tissues! Blood vesselsFig. 1: Semicoronal image showingall of the posterior articular surfaceof the subtalar joint and portions ofthe medial and lateral malleoliFig. 2: Semicoronal image showingthe posterior articular surface, all ofthe tarsal canal, and the susten-taculum

MRI: JointsImportant
DataPositionSemicoronal image plane:1 Calcaneal valgus angle = relation of the talar axis (line con-necting the bisectors of the corners of the ankle and subtalarjoint surfaces) to the axis of the calcaneus (line connecting thebisectors of the corners of the subtalar joint and a line parallelto it through the narrowest part of the calcaneus):! Approximately 0° ± 10°2 Sustentacular angle (formed by a line connecting the cornersof the lateral posterior joint surface and sustentaculum and aline perpendicular to a tangent to the sustentaculum and me-dial calcaneal tuberosity):! 18!28°Axial image plane (image is acquired 4 cm above the level wherethe lateral part of the talus is first visualized):3 Plantar talocalcaneal angle (formed by a line connecting thelateral corner of the posterior articular surface of the talus andthe medial corner of its medial articular surface with a linebisecting the calcaneal articular surface and the midpoint of aparallel line through the caudal third of the calcaneus):! 60!70°4 Calcaneocuboid angle (angle between the longitudinal axes ofthe cuboid and calcaneus):! Approximately 20!35°5 Arch angle (angle between tangents to the inferior calcanealborder and the soft-tissue sole):! 20!30°6 Achilles tendon:! Anteroposterior diameter < secondmetatarsals =" 7.4"> 9° is suspicious for hallux valgus)! Relation of calcaneus to talus: 1.8!2.18 Boehler’s angle (formed by a line connecting the posterosupe-rior and anterosuperior prominences of the calcaneus and aline through the sustentaculum tali):! 20!40° (signifies calcaneal integrity) Ankle and Subtalar JointsFig. 3: Axial image 4 mm above theplane in which the lateral part of thetarsus is first visualizedLocation of the semicoronal and axial image planes Axial image 8!10 mm abovethe plane in which the articular sur-face of the calcaneocuboid joint isfirst visualized MRI: JointsSagittal imageCoronal image MRI: Special InvestigationsCranial VesselsThe internal carotid arteries show normal course and caliber and aresymmetrically disposed. Each carotid siphon is normal, showing no dis-placement or extrinsic compression. Intraluminal signal intensity is ho-mogeneous.The middle cerebral artery arises normally from the internal carotid oneach side and forms normal insular loops. There is no circumscribedvascular narrowing or dilatation. The vessel lumen shows homo-geneous signal intensity.The anterior cerebral artery shows no signs of narrowing or displace-ment.The basilar artery shows a normal course and caliber and divides intonormal-size posterior cerebral arteries. The anterior and posterior com-municating arteries on each side are normally developed and of normalsize. No segments show convolution or circumscribed dilatation.The other evaluable portions of the neurocranium show no abnormali-ties.InterpretationThe cranial vascular system appears normal.ChecklistInternal carotid ! Extracranial portionartery ! Siphon! Intracranial portionMiddle cerebralartery! M1, M2, and M3 segmentsAnterior cerebral ! Position (no displacement)artery ! Course! Caliber (symmetry)! Signal characteristics (homogeneous intralumi-nal signal, no filling defect)! Contours (smooth, no circumscribed or beadedconstrictions) MRI: Special Investigations! No circumscribed outpouching (especially in theproximal and horizontal segments)Basilar artery ! Position! Course (no excessive tortuosity, no impressionon brain stem)! Caliber (no general or circumscribed luminal di-latation)! Signal characteristics (homogeneous intralumi-nal signal, no filling defect)! Contours (smooth)Posterior cerebral! Positionartery ! Symmetry! Course! Caliber (symmetry)! Signal characteristics! No excessive tortuosity! No circumscribed dilatation, especially in theproximal segmentAnterior and ! Presenceposterior ! Coursecommunicating ! Caliberarteries ! Signal characteristicsVenous vessels ! No arteriovenous communicationsNeurocranium ! No abnormalities(imaged portions)MR angiogram of the cranial arteries, coronal view. Cranial VesselsMR angiogram of the cranial arteries, axial view.
MR angiogram of the cranial arteries, lateral view MRI: Special InvestigationsCranial Venous VesselsMRI of the venous cranial vessels demonstrates a superior sagittal sinusof normal caliberwith normal arrangement of draining superficial cere-bral veins. The great cerebral vein and inferior sagittal sinus appear nor-mal. The transverse sinus presents a normal caliber and usually showsslight asymmetry between the right and left sides. The other evaluabledeep cerebral veins are normally developed and patent. No venous seg-ments contain flow voids or filling defects.The other evaluable portions of the neurocranium show no abnormali-ties.InterpretationThe cranial venous vascular system appears normal.ChecklistSupratentorialvenous system! Superior sagittal sinus, superficial cerebral veins(ascending cerebral veins), deep cerebral veins:— Internal cerebral vein— Great cerebral vein (of Galen)— Straight sinus— Superficial middle cerebral vein— Sphenoparietal sinus— Cavernous sinus— Inferior petrosal sinus! Sinus confluence! Transverse sinuses (bilaterally symmetrical onlyin 20% of cases; 25% of cases have unilateraldrainage, and more than 50% of cases show pre-dominant right-sided drainage; bilateral asym-metry is normal, usually with a right-sided pre-dominance)! Sigmoid sinus! Jugular bulbInfratentorial ! Position (no displacement)venous system ! Course (no excessive tortuosity, normal calibers,no general or circumscribed luminal dilatation)! Signal characteristics (homogeneous intralumi-nal signal, no filling defect)! Contours (smooth, no constrictions) Cranial Venous Vessels! No circumscribed outpouching! No arteriovenous communicationsNeurocranium ! No abnormalities(imaged portions)Phase-contrast angiogram of the cranial veins, anteroposterior view MRI: Special InvestigationsPhase contrast angiogram of the cranial veins, lateral viewContrast-enhanced maximum intensity projection (MIP) emphasizing the cranialveins, lateral view MR Angiography of the Renal ArteriesMR Angiography of the Renal ArteriesThe abdominal aorta displays normal course and caliber.The renal arterial trunks are paired, arise at the proper level, and shownormal distribution. The course, calibers, and contours of the renal ves-sels are normal, with no evidence of caliber irregularities.The kidneys are paired and are normal in their position, shape, size, andborders.Other imaged vessels show no abnormalities.InterpretationThe renal arteries appear normal.ChecklistAbdominal aorta ! Position (almost straight course slightly to left ofmidline)! Diameter No caliber irregularities! No circumscribed or segmental narrowingRenal arteries ! Number (paired)! Accessory polar arteries! Origin from the aorta Further distribution (anterior and posteriormainbranches, segmental arteries)! Diameter No caliber irregularities (circumscribed, seg-mental, beaded)! No pathological vessels! No stretching or splayingRenal paren- ! Paired renal organschyma ! Position Size (see below)! Smooth organ contoursRenal pelvis ! Structure! Bilateral symmetry! Width! Shape of calicesUreters ! Not duplicated (one per side)! Course MRI: Special Investigations! Diameter (see below)! No obstruction of urinary drainageOther imaged ! Coursevessels (e.g., iliac ! Caliber vessels, spinalarteries, superiorand inferior mes-enteric arteries)Venous phase ! Course(if documented, ! Caliber (see below)e.g., inferior venacava and renal veins)Important Data1 Abdominal aorta:! Approximately 18!30 mm2 Aortic bifurcation:! At approximately the L4-L5 level3 Origin of renal arteries:! At approximately the L1-L2 level4 Renal artery:! Diameter approximately 4!10 mm5 Position of superior poles of kidneys:a Right: superior border of L1b Left: inferior border of T12 (right kidney is lower than leftkidney by up to one vertebral body height)6 Distance between superior renal poles:! Approximately 10 cm (4!16 cm)7 Distance between inferior renal poles:! Approximately 13 cm (9!18.5 cm)8 Renal dimensions:! Craniocaudal: 8!13 cm (<1.5> 5 cm is suspicious for hy-drops)2 Width of common bile duct:! ! 8 mm (after cholecystectomy: ! 10 mm)3 Cystic duct:! Length ca. 4 cm4 Pancreatic duct:! Width: 1!3 mm MRI: Special InvestigationsCervical ArteriesThe aortic arch presents smooth walls and normal configuration.The brachiocephalic trunk arises normally and undergoes a normal di-vision into the subclavian artery, common carotid artery, and rightvertebral artery. The left common carotid artery arises directly fromtheaortic arch, has a normal caliber, and shows no luminal narrowing orfilling defects. The vertebral artery appears normal.The carotid bifurcation occurs at a normal level on each side and is nor-mally shaped. The external carotid artery and particularly the internalcarotid artery are symmetrical on each side and have normal calibers.There is no circumscribed narrowing or expansion.The vessels display a homogeneous intraluminal signal. The carotid si-phon appears normal, showing no displacement or extrinsic compres-sion.The vertebral arteries are symmetrically disposed and take a normalcourse. They show normal luminal diameters with no filling defects orcaliber irregularities as far as the basilar artery.The portions of the neck that are imaged and evaluable show no abnor-malities.InterpretationThe supra-aortic system of arterial cervical vessels appears normal.ChecklistAortic arch ! General form! Course! Caliber! Signal characteristicsOrigins: brachiocephalic trunk, left commoncarotid artery, left subclavian arteryBrachiocephalic ! Origintrunk ! Division into right subclavian and right commoncarotid arteriesLeft and right ! Positionsubclavian ! Coursearteries ! Caliber! Signal characteristics. Cervical ArteriesCommon carotidartery! Origin (usually the left artery arises directly fromthe aortic arch while the right artery arises withthe subclavian artery from the brachiocephalictrunk)! Symmetry! Course! Caliber (symmetry)! Signal characteristics! No excessive tortuosity! No circumscribed dilatationCarotid ! Usually occurs at C4/5 or C3/4 levelbifurcation ! Shape! No circumscribed narrowing, especially at theorigin of the internal carotid arteryInternal carotid ! Position (no displacement)artery ! Course! Caliber (slight proximal dilatation due to thecarotid sinus, right!left symmetry)! Signal characteristics (homogeneous intralumi-nal signal, no filling defect)! Contours (smooth, no circumscribed constric-tion or ulceration)! No circumscribed narrowing (especially in theproximal segment) with poststenotic dilatation! Symmetrical appearance of the carotid siphonsExternal carotid ! Positionartery ! Course! Caliber! Signal characteristicsVertebral artery ! Origin (from the subclavian artery or, rarely,from the aortic arch)! Position! Course (no excessive tortuosity)! Caliber (no general or circumscribed luminal di-latation)! Caliber discrepancy (usually left > right) is com-mon! Signal characteristics (homogeneous intralumi-nal signal, no filling defect)! Contours (smooth)

MRI: Special Investigations
Important DataSites of predilection for stenosis:! Internal carotid artery:— Carotid bifurcation (ca. 2/3 of all carotid stenoses)— At entrance to the carotid siphon— Within the carotid siphon! Vertebral artery— Origin from the subclavian artery— Passage through dura at craniocervical junction