Ventriculus terminalis
5th ventricle Dilatation of terminal spinal cord canal
Altman surgical classification of sacrococcygeal teratoma
Type I: primarily external – best prognosis 47% Type II: Dumbell shape with equal external and internal component 34% Type III: mainly internal within abdomen and pelvis 9% Type IV: internal completely 10%, worst prognosis
L2 hydroxyglutaric aciduria
hyperintensity of subcortical white matter normal periventricular white matter hyperintense basal ganglia putamina bilateral cerebellar nuceli hyperintensity
Alexander disease
hyperintensity in subcortica, deep and periventricular white matter hyperintense basal ganglia
Vanishing white matter disease
hyperintensity of deep white matter normal subcortical white matter areas of cavitation
GM2 gangliosidosis
hypomyelination of white matter T1 thalmic hyperintensity, T2 hypointensity
Glutaric aciduria type I
hypoplasia of frontal and temporal insulae open sylvian fissures hyperintensity of posterior putamina
Late infantile neuronal ceroid lipofuscinosis LI-NCL
Diffuse cortical atrophy, sulcal, lateral ventricle enlarged, marked cerebellar atrophy, enlarged 4th ventricle
Schizencephaly
Clefts in brain that extende from cortex to ventricle lined by dysplastic gray matter
Lissencephaly
arrested neuronal migration thick 4 layer cortex hourglass or figure of 8 cerebral hemisphere shape posterior > anterior involvement
Colpocephaly
dilated atrium/occipital horns of lateral ventricle absent corpus callosum vertical posterior course of anterior cerebral artery
Tennis leg
partial or complete tear of plantaris myotendon
Discoid meniscus
More than 14 mm medial to lateral meniscal width commonly involves lateral meniscus failure of resorption of central portion Watanabe classification Complete Incomplete Wrisberg type: no posterolateral meniscal attachment to tibia
Meniscofemoral ligament
From posterior horn of lateral meniscus to medial wall of intercondylar notch Humphrey: ligament passes anterior to posterior cruciate ligament Wrisberg: ligament posterior to posterior cruciate ligament
Chondral injury classification
grade 0: normal grade 1: softening grade 2: partial thickness defect, <50% cartilage depth grade 3: partial thickness defect, >50% cartilage depth grade 4: full thickness defect with or without underlying bone changes
Sinding Larson Johannson syndrome
chronic traction or avulsion of proximal patellar tendon at inferior pole of patella
Osgood Schlatter disease
repetitive traction/avulsion at patellar tendon insertion on tibial tubercle
Sever disease
fragmented sclerotic apophysis of posterior calcaneal process
Kager fat pad
Pre Achilles fat pad
Haglund deformity and triad/syndrome
Deformity: enlarged superior margin of posterior process of calcaneus Triad/syndrome
Check rein deformity
tethering of flexor hallucis longus tendon by flexor retinaculum
Master knot of Henry
place where flexor hallucis longus crosses flexor digitorum longus in foot
Weinstabi classification of achilles injury
Type I: inflammatory response Type II: degenerative changes Type III: partial tear Type IV: complete tear
Skimboarder toe
rupture of dorsal joint capsule due to hyperdorsiflexion
Sand toe
rupture of dorsal joint capsule due to plantar flexion
turf toe
rupture of plantar plate due to hyperdorsiflexion
Chaput Tillaux fracture
avulsion of anterior inferior tibiofibular ligament from lateral margin of anterior tibia
Volkman fracture
Earle fracture posterior inferior tibiofibular ligament avulsion from lateral aspect posterior malleolus
Freiberg infraction
2nd metatarsal head osteonecrosis or osteochondral fracture Mottled sclerosis and lucency flattening of head bone marrow edema Smillie classification Stage I: epiphyseal fissure surrounded by sclerosis Stage II: mild subchondral collapse Stage III: prominent medial and lateral projection of MT head Stage IV: MT head projection fracture, central area of collapse Stage V: extensive articular…
Stress response, fatigue and insufficiency fractures
Stress response: bone marrow edema, long segment periosteal reaction but no fracture line Fatigue fracture: abnormal stress on normal bone Insufficiency fracture: normal stress on weak bone
5th metatarsal fractures
Tuberosity avulsion fracture Jones: metadiaphyseal junction traumatic fracture Stress: similar to Jones, more distal
Lisfranc fracture dislocation types
Homolateral: all metatarsals displaced laterally Divergent: 1st metatarsal displaced medially with rest displaced laterally Partial: not all TMT joints involved Isolated: single TMT joint dislocation Longitudinal: medial displacement of first MT and TMT from rest of Lisfranc joint
Lisfranc ligament
Three components
Sangeorzan classification of navicular body fractures
Type I Coronal fracture, no dislocation Type II Dorsolateral or plantar medial fracture with medial forefoot displacement Type III Comminuted fracture with lateral forefoot displacement
Sanders classification of calcaneal fractures
Two categories Based on number of fracture lines Type I non displaced, no matter how many fracture lins Type II single displaced fracture line – 2 part Type III two displaced fracture lines – 3 part Type IV comminuted Based on position of main fracture line A: lateral 1/3 of joint B: middle 1/3 of…
Hawkins classification of talar neck fractures
Type 1 Non-displaced Type 2 Displaced with posterior subtalar joint disruption Type 3 Displaced with disruption of both ankle and posterior subtalar joints Type 4 Displaced with disruption of ankle, posterior subtalar and talonavicular joints
Osteochondral lesion of ankle
The two common sites posteromedial and anterolateral talar dome Focal injury of articular cartilage and underlying bone sclerotic fracture line concavity of subchondral bone
Weber classification of malleolar fractures
Type A fracture below level of tibial plafond Type B fracture at level of tibial plafond Type C fracture above level of tibial plafond
Os Vesalianum
accessory centre of styloid process base of 5th metatarsal
Os Peroneum
Peroneus longus sesamoid Near lateral margin cuboid ostitis in psoriatic or reactive arthritis, tendinopathy
Ossicles around the navicular bone
Os supranaviculare at dorsal proximal margin Accessory navicular type 1: sesamoid in tibialis posterior tendon type 2: os tibiale externum. at plantar margin of median eminence of navicular. tibialis posterior inserts on this os type 3: enlarged median eminence
Os trigonum
Posterior process of talus Anterior apex Tear drop shape
Sesamoid bone
Ossicle within a tendon Arises to provide a mechanical advantage
Talar axis
Longitudinal line through talus It is aligned with a longitudinal line through the first metatarsal When talar axis below 1st MT axis, pes planus When talar axis is above 1st MT axis, pes cavus
Ankle joint space
Evaluate joint in mortise view Look at medial, lateral and superior components Normal space: <4 mm Equivocal: 4-6 mm Abnormal: >6 mm, suggests ligament injury
Standard foot MRI protocol
Sagittal T1 and STIR Axial T1 and PD fs Coronal PD and T2 fs
Standard views ankle radiograph
AP Mortise Lateral
Lisfranc joint and ligament
Collective name for tarsometatarsal joints Lisfranc ligament maintains stability. Consists of 3 bands that extend from 1st cuneiform to medial base of 2nd metatarsal Injured in forcible plantar flexion of midfoot. Seen as lateral subluxation of 2nd TMT on weight bearing radiograph
Chopart joint
Components: talonavicular and calcaneocuboid joints Both are separate joint cavities but together called the Chopart joint Supination and pronation occurs here
Subtalar joint
3 facets: anterior, mid and posterior The anterior and mid facets form the anterior subtalar joint Posterior subtalar facet forms the posterior subtalar joint which is a separate joint cavity. It bears 50% of the weight and in 15% of population communicates with ankle joint. Inversion, eversion and gliding motion permitted in this joint Anterior…
Components of foot
Forefoot: metatarsals and phalanges Midfoot: all tarsal bones other than talus and calcaneum Hindfoot: talus and calcaneum
Lateral collateral ligament of ankle
Components: anterior and posterior talofibular ligament and calcaneofibular ligament Protects from inversion, anterior translation and rotation stress
Syndesmotic ligaments of ankle
Components include: anterior inferior and posterior inferior tibiofibular ligaments and interosseous ligament Anterior inferior tibiofibular ligament has an accessory band called the Basset ligament slightly inferior to it Posterior inferior tibiofibular ligament has another component inferiorly called the transverse (intermalleolar) ligament Injured in eversion or pronation stress or a rotational injury Keeps fibula in fibular…
Pilon fractures
Axial load injuries Articular surface of tibia is disrupted
Extramedullary hematopoiesis
Compensatory mechanism to increase bone marrow function Seen in thalassemia, hereditary spherocytosis, sickle cell anemia Typically in lower thorax Symmetrical, bilateral Marrow bursts out of bone and appears as soft tissue mass May have fatty content within
Lateral thoracic meningocele
Rare Redundant spinal meninges protrudes through intervertebral foramen Contains CSF Asymptomatic Difficult to distinguish from neurogenic tumors
Non accidental trauma / child abuse
Common sites of fracture
Mondor disease
Superficial thrombophlebitisJust under the skinClinically visibleShould distinguish from dilated ducts with intraduct contentVein cannot be compressed due to thrombosisOften not detected on mammogram
Sternalis muscle
Rare variantTriangular or round in shapeSeen medially adjacent to sternumLook for it in the CC view of mammogramKnowledge of this is imperative to rule out a mass
Poland syndrome
Varying degress of hypoplasia or even absence ofCostosternal component of pectoralis majorSerratus anteriorExternal obliqueCostal cartilagesMay be associated with syndactyly, other upper limb deformitiesIpsilateral breast maybe hypoplastic or absent
Polythelia, polymastia
Polythelia: accessory nipplesPolymastia: accessory breasts
Levels of axillary lymph nodes
Level IInferior and lateral to pectoralis minorLevel IIRotter nodes – beneath pectoralis minorLevel IIISuperior to pectoralis minor Level I and II usually removed in full dissection
Paget disease of the nipple
Carcinoma in situ from nipple epidermisNipple areola thickening and retractionNo obvious findings in ultrasoundAbnormal nipple enhancement in post Gd MRI
Ductal carcinoma in situ
Malignancy from epithelial cells of terminal duct lobular unitNo basement membrane invasionCalcification is the most common finding – fine linear or branching, tend to be a cluster seen accompanying dilated ducts which have indistinct walls. Associated mass suggests invasion
Phyllodes tumor
Can be benign or malignantArises from periductal stromaThe papillary growth pattern is the origin of the name ‘Phyllodes’ (leaf-like in Greek)Large rapidly growing without calcifications. Calcifications when present (rare) are large and chunkyDifficult do distinguish from a highly cellular fibroadenomaThe clefts in the papillary growth appear as cystic spaces on imagingCellular lesion is iso intense…
Fibromatosis of breast
Aggressive growth of fibroblasts and myofibroblastsArises typically from pectoralis fasciaHence the mass is often seen closely related to pectoralis majorLarge spiculated dense lesionHypoechoic on ultrasound, hypointense on MR sequences with variable enhancement post contrastMRI best for delineating extent prior to excision
Pseudoangiomatous stromal hyperplasia (PASH)
Benign lesionMyofibroblastic hyperplasiaRound or oval shaped 5-10 cm sized well defined lesionVery slow growingNo typical echogenicity or enhancement patternsCore biopsy diagnostic
Papilloma breast
Benign proliferation of duct epithelial and myoepithelial cells70% lesions central, involves main ducts in subareolar region30% occurs in peripheral breast, in terminal duct lobular unitsLesion is occult usually in mammographyUltrasound and galactography are high yieldingUse generous gel, roll nipple to the side, and use an angled view to evade the sub- nipple shadowingUltrasound shows dilated…
Fibrocystic change of breast
A mixture of cysts, fibrosis and adenosisDiffuse involvement of both breastsScattered calcifications, varying densities of glandularity, temporally changing cystsCysts can be macro, cluster of micro, regional or diffuseThis condition make it harder to detect any new onset malignancy and these patients should be monitored more closely
Fibroadenoma breast
Most common benign tumorAdult and juvenile formContains stromal and epithelial elementWell circumscribed, oval lesions with edge shadowing, posterior enhancement on ultrasound, wide than tall. Hypermobile under the ultrasound probeIsointense to breast in T2 and can be seen to rapidly enhance post i.v. contrast administrationCalcifications are commonly seen, causing edge shadowingPseudocapsule due to compression of adjacent…
Fibroadenolipoma breast
Breast-within-breastPseudoencapsulated lesion containing varying levels of glandularity and fatBenignCan occur at any site in breast or in ectopic breast
Diffuse calcifications in breast
Random distribution of calcifications in both breastsOften benignDifferentialsAdenosis: premenopausalSclerosing adenosis: postmenopausalFibrocystic diseaseSkin calcificationsVery rarely extensive DCIS
Vascular calcifications
BenignAtherosclerotic changes in intima mediaSerpiginous, linear and plaque typeSometimes dot-dash appearanceSnake-skin, patchy marble appearance
Secretory calcifications in breast
Duct ectasia with secretory depositsBenign calcificationsLarge rod shaped / cigar shapedShow a ductal pattern radiating from nipple3-10 mm longTends to be bilateral and extensive
Oil Cyst
Liquefied fatCan be seen in any part of breastMost common in subareolar regionRange from few mm to cm in size Mammography Oval to round lucent smooth border lesionDevelops rim calcification over timeCalcification can be rim, egg-shell or coarseIn early stages, same as surrounding fat and difficult to detect Ultrasound Myriad of echogenicity – hyper, iso…
Well Defined Margins
A descriptor terminology used in lesion characterization in imagingWhen at least 75% of the margins can be clearly distinguished from surrounding tissue
PD weighted imaging
Manipulating TR and TE helps us to weight the contrast of the image to a certain parameter while diminishing the impact of other parametersIn PD weighting, the intrinsic contrast of tissues is accentuated. This is done by reducing the T1 and T2 effects on imagingA long TR reduces T1 effects, a short TE reduces T2…
T2 weighting
Manipulating TR and TE helps us to weight the contrast of the image to a certain parameter while diminishing the impact of other parametersIn T2 weighting, the T2 relaxation time of tissues is accentuated and the T1 effects decreasedHow we achieve this is by using a long TE – which allows both fat and water…
T1 weighted imaging
Manipulating TR and TE helps us to weight the contrast of the image to a certain parameter while diminishing the impact of other parametersIn T1 weighting, the T1 relaxation time of tissues is accentuated and the T2 effects decreasedHow we achieve this is by using a short TR – which prevents fat or water to…
T2 decay
Decay of NMV in the transverse plane in an exponential mannerOccurs due to spin-spin interactionsThe intrinsic magnetic fields of nuclei causes loss of coherence, resulting in dephasingIt is intrinsic to tissueTime taken for 63% of the transverse magnetization to be lost due to dephasingThis dephasing occurs during TE – the time between the RF pulse…
T1 recovery
Also known as spin lattice energy transferIt is the time taken to for the spins to dissipate energy so that they regain their longitudinal magnetizationIt is an exponential processIt is tissue specificDefined as time taken for 63% of the longitudinal magnetization to be recoveredThe time taken for this extends from one RF pulse to the…
Pulse sequence
Series of RF pulses, gradients and intervening time periodsTime period determines image weightingSequence is needed to produce signals sufficient enough to form an imageChanging TE and TR enables forming different types of contrastSpins are rephased using180 degree RF pulse – conventional spin echo, fast or turbo spin echo, inversion recovery, STIR, FLAIRGradient – coherent gradient…
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