MRI CAMRT: Pathology questions with correct answers, Exams of Nursing

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MRI CAMRT: Pathology questions with

correct answers

Abscess (brain): definition and imaging appearance on T1, T2, CE, and DWI Answer✓✓ Collection of pus. Mass effect and extensive surrounding edema. T1: hypointense to grey matter T2: hyperintense to grey matter with surrounding edema. CE MRI: ring-like enhancement DWI shows an abscess having a high DWI signal with corresponding low signal on the ADC map. Avascular Necrosis (AVN) Answer✓✓ T1: necrotic area is hypointense T2: hyperintense bone marrow edema Ischemic area remains hypointense. Double line sign. Hypointense outer line due to sclerosis and fibrosis and a hyperintense inner line. Acoustic neuroma: AKA? Benign or malignant? Appearance on T1, T2, CE? Answer✓✓ AKA vestibular schwanoma Benign tumour of schwann cells covering the vestibule portion of the 8th cranial nerve (vestibulocochlear nerve). Seen in the cerebellopontine angle cistern T1: isointense to slightly hypointense T1 CE: hyperintense enhancement

T2: Hyperintence Agenesis of the corpus callosum: definition and appearance Answer✓✓ the congenital absence of corpus callosum which may be partial or complete due to an insult occurring prior to 10th week gestation. Elevated 3rd ventricle, noticeable separation of the lateral ventricles, partial or complete absence of the corpus callosum and dysplasia of the cerebellum. Ventricles may be enlarged Alzheimer's disease: Appearance, and spectroscopy Answer✓✓ Diffuse cortical atrophy, most prominent in the temporal lobes. Hippocampal atrophy may be seen Increase in the size of the ventricles, sulci, sylvian fissures, and total CSF volume. Reduced levels of N-acetyl asparate (NAA) Increased levels of myoinositol Aneurysm (brain): causes, location, T1, T2 appearance Answer✓✓ Berry aneurysms are small saccular aneurysms that commonly form on th earteries of the COW. Can be associated with PKD and coarctation of the aorta. Often asymptomatic/incidental finding. Often rupture and cause subarachnoid hemorrhage. T2: Rounded lesion with internal signal void.

Edema and mass effect may be seen. Cavernous angioma Answer✓✓ Cavernous angioma is a vascular malformation consisting of variable sized inter-capillary spaces, sinusoids, and larger cavernous spaces with no normal intervening brain tissue. Seizures and neurological deficit. Prone to thrombosis and hemorrhage. Slow flow lesions therefore not routinely identified at cerebral angiography. T2* for detecting blood breakdown products Black halo on T2 due to peripherally deposited hemosiderin deposits which causes significant T2 shortening. Chiari Malformation Answer✓✓ Chiari I: malformation: herniation of the cerebellar tonsils below the foramen magnum. Chiari II: cerebellar hypoplasia, caudal displacement and narrowing of the 4th ventricle, 90% have hydrocephalus, presentation in early childhood. Decent of cerebellar tonsils .5 mm below foramen magnum. Often an associated syrinx, and hydrocephalus. Arachnoid Cyst Answer✓✓ Benign. extraaxial, CSF-filled fluid mass that does not communicate with the ventricles.

T1: hypointense T2: hyperintense Colloid cyst Answer✓✓ Typically arise in the anterior aspect of the 3rd ventricle T1: hyperintense T2: hypointense most are of low T2/T2* signal (short T2), related to thick "motor oil" consistency fluid Dandy-Walker malformation Answer✓✓ Non-communicating type of hydrocephalus. Dandy-Walker malformation (DWM) is the most common posterior fossa malformation, characterized by the triad of: hypoplasia of the vermis and cephalad rotation of the vermian remnant cystic dilatation of the fourth ventricle extending posteriorly enlarged posterior fossa with torcular-lambdoid inversion (the torcula lying above the level of the lambdoid due to abnormally high tentorium) T1 hypointense T2 hyperintese Encephalitis Answer✓✓ T1: hypointense areas of edema

T1: varied signal depending on the age of the blood products, small fluid-fluid levels may be evident T2 hypointense rim varied signal internally depending on the age of blood productsif a recent bleed has occurred, surrounding edema may be present GRE T2*/SWI prominent blooming useful for detecting smaller lesions otherwise missed by conventional spin echo sequences, especially in patients with familial or multiple cavernous malformations T1 CE (Gd): generally no enhancement Brain hemorrhage: What are the time frames and appearance of each of these? hyperacute Acute Subacute late subacute chronic Answer✓✓ Hyperacute: < 24 hrs oxyhemoglobin T1 iso/hypo T2 iso/hypo Acute (1-3 days) deoxyhemoglobin:

T1: Isointense/hypointense T2: Hypointense Early subacute (4-7 days) intraacellular methemoglobin T1: Hyperintense T2: Hypointense Late subacute 7-14 days extracellular methemoglobin T1: Hyperintense T2: Hyperintense dark rim of hemosiderin on both Chronic (2+ weeks): T1: Hypointense T2: Hypointense dark rim of hemosiderin on both Hydrocephalus Answer✓✓ May result from over production of CSF, under re- absorption, or obstruction of the ventricles. T1: enlarged ventricles will be hypointense

as 3 days after infarction 10. After day 5 the cortex usually demonstrates contrast enhancement on T1 C+ Subacute ADC demonstrates pseudonormalization typically occurring between 10-15 days

10. As ADC values continue to rise, infarcted tissue progressively gets brighter than normal parenchyma. In contrast, DWI remains elevated due to persistent high T2/FLAIR signal Chronic T1 signal remains low with intrinsic high T1 in the cortex if cortical necrosis is present 10. T2 signal is high. Cortical contrast enhancement usually persists for 2 to 4 months Medulloblastoma Answer✓✓ Rapidly growing, highly malignant tumour originating in the medullary velum (midline structure that makes up part of the roof of the 4th ventircle). T1: hypo/iso intense T2: hyperintense Meningioma Answer✓✓ slow growing, usually highly vascular, benign intracranial tumour. Usually occurs along the meningeal vessels and superior longitudinal sinus. T1: iso to slightly hypointense.

T2: Isointense to slightly hypointense T1 CE: very hyperintense, homogenous Dural tail sign Meningitis Answer✓✓ inflammation of the meninges Best seen on FLAIR, and T1 CE. Mesial temporal / sclerosis / epilepsy/seizures Answer✓✓ also commonly referred to as hippocampal sclerosis, is the most common association with intractable temporal lobe epilepsy (TLE) reduced hippocampal volume: hippocampal atrophy increased T2 signal Mesial: the term comprises five structures located in the middle temporal lobe: amygdala hippocampus uncus dentate gyrus parahippocampal gyrus Metastatic tumors Answer✓✓ Intracranial mets usually spread via blood from primary cancers of the breast, lung, GI tract, kidney, and melanoma.

T1: hypointense T2: hyperintense FLAIR: hyperintense T1 CE: low grade oligodenroglioma wont enhance while an anaplatic oligodenroglioma will Optic neuritis Answer✓✓ Optic neuritis denotes inflammation of the optic nerve and is one of the more common causes of optic neuropathy. It can be thought of as broadly divided into infectious and non-infectious causes, although the latter is far more frequent. On imaging, optic neuritis is most easily identified as a unilateral optic nerve swelling, with high T2 signal and contrast enhancement. Pituitary macroadenoma Answer✓✓ Measure larger than 10 mm T1: hypointense T2: variable and unpredictable signal intensity T1 CE: hyperintense Other text: most adenomas are low signal on T1, high signal on T Pituitary microadenoma Answer✓✓ Measure less than 10 mm T1: hypointense T2: variable and unpredictable signal intensity T1 CE: little enhancement

Other text: most adenomas are low signal on T1, high signal on T Microadenomas show little enhancement. Retinoblastoma Answer✓✓ Retinoblastoma (Rb) is a rare form of cancer that rapidly develops from the immature cells of a retina, the light-detecting tissue of the eye. It is the most common primary malignant intraocular cancer in children, and it is almost exclusively found in young children. T1: intermediate signal intensity, hyperintense compared to the vitreous T2: hypointense compared to the vitreous T1 C+ (Gd)the mass usually enhances relatively homogeneously DWI: the tumor shows restricted diffusion on DWI at high b values. It exhibits low ADC values in contrast to the high intensity of the vitreous in the ADC maps ADC map can be used to differentiate viable and necrotic tumor Schwannoma (vestibular) Answer✓✓ Benign slow growing tumour of the schwann sheath. Most common tumour in the cerebellopontine angle. Association with neurofibromatosis. T1: isointense T2: hyperintense T1 CE: avid homogeneous enhancement

T2*: an area of hyperintense blooming i sseen with acute hemorrhage DWI: hyperintense, hypointense on ADC map. Stroke / cerebrovascular accident (CVA): Hemorrhagic stroke Answer✓✓ Results from a ruptured blood vessel in the brain. Associated with hypertension, arteriosclerosis, and aneurysm. Acute (24-72 hrs): T1: isointense to hypointense T2: hypointense Early subacute (4-7 days) T1: hyperintense T2: hypointense late subacute (1-4 weeks) T1: hyperintense T2: hyperintense chronic (2+ weeks) T1: Hypointense T2: Hypointense subarachnoid hemorrhage (SAH) Answer✓✓ Bleeding into the subarachnoid space usually in the basal cisterns and into the CSF pathways. Usually the result of a berry aneurysm rupture.

FLAIR is the most sensitive sequence. Blood will be hyperintense. Conventional T1 and T2 are not very useful. Subdural Hematoma (SDH) Answer✓✓ Collection of venous blood between the dura mater and the arachnoid membrane (subdural space). Usually caused by trauma. Acute stage: T1: hypo to isointense T2: hypointense Subacute stage: T1: hyperintense T2: hypointense Chronic stage: T1 Intermediate signal (higher than CSF) T2: hyperintense Trigeminal neuralgia Answer✓✓ Attacks of sudden shock-like excruciating pain, which usually lasts a few seconds to about two minutes, more often involving the maxillary branch. Typically, the pain is triggered by trivial stimuli such as talking, drinking, brushing teeth, shaving, chewing and touching the face. However, it may also occur spontaneously A dedicated protocol including T2 or T1 volumetric acquisition techniques with thin slices in all three planes should be helpful. usually from vascular compression.

Angiomyolipoma Answer✓✓ Fairly common benign renal tumours. Composed of fat, blood vessels, and smooth muscle. T1: hyperintense T2: hyperintense T1 fat sat allows fat and hemorrhage within the tumour to be distinguished. Biliary tree obstruction Answer✓✓ Biliary calculi are seen as dark filling defects within the bright bile. Carcinoma (gastric) Answer✓✓ gastric carcinoma (adenocarcinoma) is one of the most common cancers. Cholecystitis Answer✓✓ 90-95% of cases are due to gallstones. Inflammation of the gallbladder. Cholelithiasis Answer✓✓ Formation of gallstones. Choledocholithiasis is gallstones in the common bile duct. Cirrhosis Answer✓✓ Cirrhosis is the end result of insult to the liver. Dysfunction of hepatocytes. Cirrhotic liver shows hererogenous signal dut to accumulation of fat, iron, fibrous tissue, glycogen and bile. Atrophy of segment 4, caudate lobe enlargement, fibrosis. May be hyperintense dysplastic nodules on T1, and hypointense on T2.

Cushing syndrome Answer✓✓ Cushing disease refers to glucocorticoid excess solely due to an adrenocorticotropic hormone-secreting pituitary adenoma, rounded face, sometimes described as 'moon-shaped MRI for pituitary gland 85% are due to pituitary adenoma, 15% from the adrenal cortex. Dissection Answer✓✓ Occurs when blood enters into the wall of an artery dissecting the layers and creating a cavity or false lumen. Ascending aorta is type A, descending type B. Black blood imaging often used. Intimal flap appears as a hypointense line with a linear or S shape. Fatty Liver Answer✓✓ Imaging findings: Higher than normal signal of T1 or T2 images In phase/out of phase sequences: when fat and water coexist in a voxel owing to chemical shift there will be signal drop out from fat on out of phase imaging. Can be diffuse or multifocal. Spleen is used as an internal reference for signal intensity. Fistula Answer✓✓ MRI is the imaging modality of choice. Active fistulous tracts are typically: