RITE Neuroimaging

This causes focal cerebritis rather than diffuse edema in the temporal lobes.

Toxoplasmosis

Question 218: Toxoplasmosis is caused by an obligate intracellular parasite Toxoplasma gondii. Patients who develop _____ are at particularly high risk of disseminated toxoplasmosis which most frequently involves the CNS. Toxoplasmosis is the most common focal mass lesion in this and it most commonly involves the _______ ______.

AIDS; basal ganglia

This disease is characterized by subcortical foci of patchy T2 hyperintensities in white matter

Binswanger

Question 227: There is cerebellar tonsillar ectopia (approximately 1 cm below the foramen magnum) with an associated cervical syrinx, findings consistent with ______ malformation. The contents of the syrinx correspond to CSF (i.e. T1 hypointense and T2 hyperintense). The lesion has distinct margins and displaces rather than infilatrates adjacent spinal cord. Astrocytomas are infiltrating tumors. Basilar invagination refers to narrowing of the foramen magnum due to upward migration of the top of the C2 vertebrae. Multiple sclerosis causes demyelinating lesions of the brain and spinal cord and is not associated with tonsillar ectopia. Chordomas are tumors of notochord remnants which most often occur in the clivus and sacrococcygeal regions.

Chiari 1

Question 229: There is restricted diffusion involving the left occipital and left lateral temporal cortices. This patient had sporadic ______-_____ disease, a progressive neurodegenerative disorder resulting from misfolded prion proteins. The imaging abnormality does not respect vascular territories, making ischemic infarction unlikely. Hypoxic brain injury typically causes symmetric abnormalities. The limbic, or medial temporal, structures appear normal. Hashimoto's encephalopathy more commonly results in lesions in the white matter and/or brain stem.

Creutzfeldt-Jakob

Question 231: This patient had gradual dementia onset and no focal full thickness cortical loss. This is often is familial wutg frontal and temporal atrophy as seen in the patient images are supportive features for diagnosis of this, though absence of atrophy does not exclude the diagnosis. It is characterized by a strong gradient of atrophy from anterior to posterior along the temporal lobe, as seen in the patient images.

Frontotemporal dementia

This is an acute febrile illness. Common early symptoms include change in consciousness (confusion, then stupor, then coma), fever, headache, and seizures. Inferior frontal lobe and medial temporal lobe involvement with edema, restricted diffusion and contrast enhancement in the acute phase, and tissue destruction later are usual findings.

Herpes encephalitis

Question 246: This case demonstrates Absent septum pellucidum, small optic nerves/chiasm compatible with ________ _____ 75-90% have brain abnormalities; 45% have pituitary insufficiency. Child with short stature, endocrine dysfunction, Normal or color blindness, visual loss, nystagmus, strabismus mental retardation, spasticity, microcephaly, anosmia.

Septooptic Dysplasia

Question 255: Type 1 odontoid fractures involve the tip of the dens and are ______ fractures.Type 2 odontoid fractures occur at the base of the dens and are considered _____. Type 3 odontoid fractures involve the base of the dens as well as the facets lateral to the odontoid process, and can be either stable or unstable.

Stable; unstable

Question 226: The patient has markedly enlarged lateral and third ventricles on axial views, with a small (or absent) cerebral aqueduct on sagittal views. These findings are most consistent with ______ _____. In ________ there is dilation of the atrium of the lateral ventricles, as in this patient, but not of the temporal horn, present here. In Dandy-Walker syndrome there is partial absence of the vermis of the _________, not present here. The Miller-Dieker syndrome includes lissencephaly, not present here. In this age group normal pressure hydrocephalus is not as frequent as this. In addition, a communicating hydrocephalus of this kind would be accompanied by some dilation of the ______ ventricle.

aqueductal stenosis; colpocephaly; cerebellum; fourth

Question 238: This study demonstrates a linear fracture defect which includes all three vertebral columns extending horizontally through the vertebral body, the pedicles, and through the facet joints. This lower thoracic fracture is termed a ______ ______, which is a fracture occurring most commonly in the lower thoracic or upper lumbar regions from T11 to L2. It is a result of hyperflexion of the back, most commonly seen in motor vehicle accidents, in belted patients, resulting in a wedge shaped compression fracture which includes posterior elements of the vertebra. Half of these patients also have an abdominal injury. This should be considered an unstable fracture until proven otherwise. Spondylolisthesis without spondylolysis is incorrect as there is no subluxation demonstrated. The fracture margins are sharply demarcated and not the pattern of chronic fractures.

chance fracture

Question 236: The CT provided demonstrates hematomas within the right frontal region, along with subarachnoid hemorrhage overlying the right hemisphere. The pattern is typical of _____ which arise in the interface between the bone surfaces. In addition, there is an obvious right parietal soft tissue hematoma. This pattern of hemorrhage with contusion is not typical of an aneurysmal rupture, nor would encephalitis present with this pattern of intracranial hemorrhages and subarachnoid hemorrhage. There is evidence of subdural hemorrhage; however, no epidural hematoma is seen in this view.

contusions

Question 248: There is gross traumatic injury to the spinal column with disruption of the C4-C5 ligamenta flava, interspinous ligaments, and posterior longitudinal ligament. There is fracture deformity of C5 vertebra consistent with a flexion teardrop fracture and fracture of C6. There is prevertebral soft tissue edema, and the cord has T2 hyperintense signal at the C5 and C6 level consistent with this and with some intramedullary hemorrhagic component. Neuromyelitis optica, ependymoma, abscess, and sarcoid myelitis are not the best choices because the extensive vertebral column injuries are not consistent with the typical presentation of any of these entities.

cord contusion

Question 245: Sagittal T1-weighted images demonstrate a loculated fluid collection in the posterior epidural space, extending for several levels in the mid-thoracic spine. The collection causes significant compression and anterior displacement of the spinal cord. Note on both sagittal and axial images that the subarachnoid space is also compressed, placing this in the epidural, not intradural space (excluding meningioma). This is a typical appearance of a loculated, _______ ______ _____. A 10-day-old hematoma should be hyperintense on T1-weighted images. Epidural metastases and myeloma are of soft tissue signal, generally nearly isointense to neural tissue and usually are anteriorly located, extending posteriorly from vertebral body lesions.

encapsulated epidural abscess

Infarction typically has an acute onset of neurologic deficit and on imaging there will be a ____ _____defect.

focal cortical

Question 243: There is a single, large infiltrative multicystic enhancing mass with vasogenic edema. This appearance is most frequently seen with a ________ _______. No vascular structures are seen as expected in an arteriovenous malformation (AVM). An infectious process, such as toxoplasmosis and a metastasis, would more likely have a ring pattern of enhancement and not the large complex multicystic pattern seen here.

glioblastoma multiforme

Question 242: The images show bilateral mesial temporal and hippocampal edema, and the clinical history supports diagnosis of this. This disease often leads to elevated RBC count in CSF due to hemorrhagic changes. JC Virus is seen in PML, a white matter disease. HTLV antibodies are seen in HTLV-associated Myelopathy/TSP.

herpes simplex encephalitis

Question 254: The CT study demonstrates near complete loss of cortical sulcation and diffuse decreased density in all hemispheres including the cerebellum along with generalized edema. These changes are in no specific vascular distribution and are typical of a severe _____ insult. The relative increased density within the fissures is a manifestation of contrast to the severe hypodensity of the remainder of the brain. Petechial hemorrhage due to necrosis may also be present. There were, however, no imaging findings to suggest a primary subarachnoid hemorrhage. Lissencephaly would not be associated with marked mass effect and edema as seen in this study; nor would hypertension encephalopathy.

hypoxic

Question 249: The combination of the patient's physical exam and neuroimaging findings is consistent with a right anterior choroidal artery infarction. The anterior choroidal artery is a branch of the internal carotid artery and supplies the posterior limb of the _______ ______ and the lateral _____.

internal capsule; thalamus

Question 230: The MRI shows an intradural extramedullary mass which is fairly homogenous and is T1 hyperintense and STIR hypointense. The STIR sequence suppresses fat signal, suggesting that this mass is composed of fat. The other answer choices are lesions which are either not composed of fat or not found in the intradural extramedullary space. This is most suggestive of a?

lipoma

Question 221: There is an ovoid homogeneously enhancing mass with adjacent vasogenic edema. A hemorrhage, hemorrhagic infarction or demyelinating lesion would not have this pattern of homogeneous enhancement. A giant aneurysm would not show this degree of edema. This pattern is most frequently seen with ______

lymphoma

Question 251: The MRI findings show the "Hot Cross Bun" sign in the pons, as well as hyperintensity in the cerebellar peduncles. These findings are most suggestive of ______ ______ ______. Parkinson disease, postencephalitic parkinsonism, and prolonged metoclopramide exposure typically would not have characteristic MRI findings. NPH would demonstrate enlargement of the ventricles along with transependymal flow.

multiple system atrophy

Question 241: MRI of the brain demonstrates markedly enlarged optic nerves, the left greater than the right, typical of _____ ____ _____. The coronal plexus study demonstrates an ovoid homogeneous enhancing lesion typical of a nerve sheath tumor. The combination of peripheral nerve sheath tumors and this is seen in conjunction with neurofibromatosis type 1 and is not a feature of the other choices. NF type 2 and schwannomatosis are not associated with these.

optic nerve gliomas

The ______ thalamic artery is a branch of the posterior cerebral artery and supplies the medial thalamus.

paramedian

Question 235: The study demonstrates increased density within the pituitary fossa extending to the cavernous sinuses bilaterally with an expansive lesion, which is demonstrated on the FLAIR and T1 view areas of both increased and decreased signal. There is an ovoid mass throughout the suprasellar cistern compressing the optic chiasm. It appears as that of a large pituitary mass, likely a _____ _____ ____. There is a perimeter of increased T1 weighted signal in the non-contrast view. A compilation of these features would be that of hemorrhagic transformation i.e. pituitary apoplexy of the pituitary tumor mass. A pituitary tumor of this size can be expected to result in bitemporal hemianopia. However, in the absence of hemorrhagic transformation, one would not expect to the tumor's presence to result in coma as seen with this patient. A colloid cyst would not be expected in this location and generally arises as an intraventricular lesion adjacent to the foramen of Monro in the third ventricle. A metastatic lesion within the sella would be in the differential of a tumor mass; however, again, it would not be the best clinical explanation for the patient's clinical presentation of sudden coma.

pituitary macro adenoma.

The ophthalmic artery is a branch of the internal carotid artery and supplies the _____.

retina

Question 219: The mass lesion with isointense signal on T1- and bright T2-weighted signal posterior to the dens is most frequently due to pannus. The inflammatory pannus involving the dens is often seen in association with _______ _______.

rheumatoid arthritis

Question 224: The study depicts a marked increase of fat tissue within the epidural space most marked from L4 to the sacral region, which results in _____ ______ as seen with a small triangular-shaped thecal sac at L5-S1. The signal characteristics are those of subcutaneous fat tissue and not CSF. Congenital for of this is a result of short pedicles is not seen on this study. The patient does have mild disc disease at L4-5 and L5-S1. They are inadequate to produce this and result in spinal claudication, as seen with this patient. The conus is not well demonstrated, but is not low-lying; nor are there any imaging features to suggest tethering of the cord.

spinal stenosis

Elevated _______ _____ levels can be seen in CNS Lyme Disease, which causes multifocal white matter lesions.

spirochete IgM

In Alzheimer disease, atrophy occurs throughout this lobe.

temporal

Question 237: The figure demonstrates widening of the CSF space posterior to the spinal cord in the mid thoracic region, resulting in anterior displacement and compression of the cord at that level best seen on the T2 weighted view with somewhat ovoid appearance. This is also well demonstrated as a region of isointense signal to CSF on the T1 weighted views and shows no enhancement. The most common etiology of this appearance is that of a ______ _____ cyst. An epidermoid cyst is an additional, although less likely, etiology and not one of the choices. A lipoma in this location would have increased T1 weighted signal similar to subcutaneous fat tissue not seen here. Similarly, a meningioma would not show the very bright T2 weighted signal and the hypodense signal on T1 weighted view. Myelomalacia within the cord may develop, although is not depicted on this study. The signal of characteristics are not hemorrhage as would be seen in an intrathecal hematoma.

thoracic arachnoid

Question 217--- The CT of the head demonstrates a hypo dense segment in the left cerebellum typical of an acute infarction, and the CTA axial view demonstrates a segment of decreased density within the left vertebral artery typical of a ______. The carotid and right vertebral artery are well demonstrated and are normal. A thrombus can occur due to atrial fibrillation, that would not be the only etiology. Similarly, trauma can result in a vertebral dissection, but again, that would not be the only possible etiology. The study demonstrates normal appearance on CT of the sigmoid sinus bilaterally and does not suggest a sigmoid sinus thrombosis. Similarly, subclavian steal is associated with posterior circulation symptoms or infarction; however, a segment of decreased density within the left vertebral artery is not the appearance seen with reversal of vertebral arterial flow.

thrombus

Question 255: Spinal immobilization and neurosurgical/orthopedic evaluation is essential for _____ odontoid fractures given their instability. In this case, the fracture results in slight anterior displacement of the odontoid fracture (seen on the sagittal image). The greater the displacement, the greater the risk of non-union. This patient underwent surgical placement of an odontoid screw for fixation of the fracture.

type 2

Question 216. Figure 3.-- The diffusion-weighted views demonstrate multiple focal areas of acute infarction. These involve both the deep gray and white matter along with scattered cortical areas of infarction. These regions of infarction are in a multifocal vascular distribution atypical for branch large vessel disease and similarly atypical for small vessel infarctions or a cardioembolic etiology, which tend to be cortical. An MRA scan of the head performed concomitant with the study illustrated demonstrated marked beading along numerous arterial structures typical of ________. This is best seen and illustrated in Figure 3 on the conventional cerebral angiogram

vasculitis