14 results
107 - Tuberous Sclerosis Complex
- from Section 4 - Abnormalities Without Significant Mass Effect
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 221-222
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Summary
Specific Imaging Findings
Tuberous sclerosis complex (TSC) abnormalities of the CNS are cortical tubers, subependymal nodules, and subependymal giant cell astrocytomas (SEGA or SGCA). Cortical tubers are typically randomly scattered focal cortical and subcortical lesions of high T2 signal that are iso- to hypointense on T1-weighted images and primarily affecting supratentorial parenchyma, but may also be found in the cerebellum. They are best depicted on FLAIR images. The tubers generally show bright signal of increased diffusivity on ADC maps and decreased cerebral blood volume on perfusion studies. Calcifications may be present and some enhance with contrast. The white matter may show radial bands of hyperintense T2 signal and cystic degeneration (usually in the deep white matter).
Subependymal nodules are multiple bilateral small (< 12 mm) sharply demarcated masses indenting the contours of the lateral ventricles. They show very low T2 signal, are frequently T1 hyperintense and enhance with gadolinium. A vast majority of subependymal nodules calcify and are hence well seen on CT and T2* MR images, as very bright and very dark nodules, respectively. SEGA are typically located at the subependymal surface of the caudate nucleus near the foramen of Monro. They are slow-growing > 12 mm minimally invasive masses with well-defined margins and avid homogeneous enhancement. Internal calcification and cysts are often present. The adjacent parenchyma is typically preserved unless anaplastic degeneration occurs. Hemimegalencephaly is also found more frequently in patients with TSC.
117 - Nodular Heterotopia
- from Section 4 - Abnormalities Without Significant Mass Effect
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 241-242
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Summary
Specific Imaging Findings
Nodular heterotopia (NH) may be located in subependymal or subcortical locations. The subependymal type (periventricular nodular heterotopia, PNH) is the more common one. The lesions show signal intensity that follows the gray matter on all MRI sequences, best seen on T1-weighted inversion recovery and FLAIR images. The nodules do not calcify or enhance with contrast and there is no associated edema. PNH lesions are typically located along the walls of the lateral ventricles causing indentation of the lateral ventricular contours. PNH is most commonly found in the peritrigonal region, it may be unilateral or bilateral, and the number and distribution of lesions varies, from a single one to a few scattered heterotopias to almost continuous nodules. The surrounding white matter and the overall appearance of the cerebral hemisphere is otherwise normal. Subcortical NH (SNH), on the other hand, shows irregular lobulated masses in the subcortical white matter, usually continuous with the overlying cortex and underlying ventricular surface without intervening normal white matter. The overlying cortex is usually thin with shallow sulci. The size of SNH heterotopias varies from a focal small lesion to a conglomerate of abnormal gray matter that involves a large part of the hemisphere. The ipsilateral hemisphere and basal ganglia may be of decreased volume.
Pertinent Clinical Information
BilateralNHis an X-linked dominant disorder with predominance in females due to a near total male mortality during embryogenesis. Clinical related symptoms are epilepsy, intelligence ranging from normal to borderline mental retardation, and coagulopathy. Sporadic heterotopias are associated with seizures and developmental delay, which varies with the severity of brain involvement. Heterotopias may be seen in conjunction with other brain malformations and syndromes, especially the subcortical type.
142 - Arachnoid Cyst
- from Section 5 - Primarily Extra-Axial Focal Space-Occupying Lesions
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 293-294
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Summary
Specific Imaging Findings
Arachnoid cyst (AC) is an extra-axial mass that follows the CSF appearance on all imaging modalities. It is sharply demarcated and displaces brain parenchyma with buckling of the adjacent intact cortex. It also displaces arteries and cranial nerves and frequently leads to thinning and remodeling of the overlying bone. AC is T1 hypointense, hyperintense on T2WI and ADC maps, dark on FLAIR and DWI and does not enhance with contrast. Arachnoid cysts are also CSF-like hypodense on CT. Hemorrhage may rarely occur within the cyst which changes the imaging appearance, depending on the blood products degradation state and proteinaceous contents. AC has a predilection for the middle cranial fossa followed by the suprasellar cisterns, cerebellopontine angle, convexities and quadrigeminal plate region.
Pertinent Clinical Information
AC is typically an incidental imaging finding, but it has been sporadically associated with headache, dizziness, sensorineural hearing loss and hemifacial spasm, depending on its location. There is increased prevalence of subdural hematomas in patients with middle cranial fossa AC. Mass effect from midline and posterior fossa ACs may lead to obstructive hydrocephalus and suprasellar AC may also cause endocrine symptoms, such as hyperprolactinemia and precocious puberty. Treatment is usually not necessary and ACs may recur following surgery. When needed, fenestration, endoscopic resection and cystoperitoneal shunt are possible options.
Differential Diagnosis
Epidermoid Cyst (143)
• engulfs vessels and cranial nerves with insinuating growth pattern
• usually heterogenous and brighter than the CSF on FLAIR images
• characteristically very bright on DWI (and signal similar to brain on ADC maps)
106 - Focal Cortical Dysplasia
- from Section 4 - Abnormalities Without Significant Mass Effect
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- By Zoran Rumboldt, Medical University of South Carolina, Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 219-220
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Summary
Specific Imaging Findings
Focal cortical dysplasia (FCD) Type I shows only localized blurring of the gray–white matter junction and sometimes decreased volume of the subcortical white matter and cortex that may be detected with dedicated high spatial resolution heavily T1-weighted inversion recovery spin echo and 3D gradient echo images. The lesions are preferentially located at the bottom of an abnormally deep sulcus. The subcortical white matter may show hyperintense T2 signal, best depicted on high-resolution FLAIR images. These findings can be very subtle, typically not seen on CT and routine MRI scans, and in a significant number of cases not even on dedicated MR imaging. Functional studies (PET, SPECT and MEG) may be able to localize the seizure focus and tailored MRI of the suspicious area with a surface coil may then depict the lesion. Co-registration of PET and MR images substantially increases sensitivity. FCD Type II shows localized cortical thickening and T2 hyperintensity, which can characteristically extend in a tapered linear fashion towards the ventricle, known as the transmantle sign. Gray–white matter junction blurring and subtle white matter T1 hyointensity may be present. The gyral pattern may be abnormal with broad gyri and irregular sulci. A lesion detected on imaging is not necessarily the seizure focus, and FCD may occur in a multifocal and multilobar distribution.
86 - Sturge–Weber Syndrome
- from Section 3 - Parenchymal Defects or Abnormal Volume
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 177-178
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Summary
Specific Imaging Findings
Sturge–Weber syndrome (SWS) shows a spectrum of findings related to leptomeningeal angiomatous changes, which consequently affect the brain parenchyma. There is atrophy of the affected brain, seen as widening of the cortical sulci and enlargement of the ventricles. Cortical gyriform calcifications are hyperdense on CT and hypointense on all MR sequences. There is an avid leptomeningeal contrast enhancement in the affected area, prominent medullary veins and enlargement of the ipsilateral choroid plexus, which can be seen on postcontrast CT or MRI. T2*-weighted MR sequences readily show calcifications, and susceptibility-weighted images (SWI) can show prominent medullary veins and sometimes the angiomatous changes without contrast administration. Intracranial SWS findings are usually unilateral, with a subtle predilection for the posterior portions of the brain, but may affect the whole cerebral hemisphere. However, SWS can also be bilateral or focal/isolated to one or a few lobes. Hypertrophy of the skull and paranasal sinuses (Dyke–Davidoff–Masson syndrome), and globe enlargement with abnormal enhancement, may also be present. Infratentorial pial angiomas are common but usually very subtle.
Pertinent Clinical Information
Patients with SWS generally develop normally until the onset of seizures, which over time become progressively refractory to medication. The overwhelming majority have a port-wine stain, usually along the V1 segment of the trigeminal nerve distribution, ipsilateral to the intracranial angiomatous changes. However, cases of SWS without port-wine stain have been described. Most patients are mentally retarded and 30% have hemiparesis. The ocular manifestations include choroidal and scleral or episcleral telangiectasia with glaucoma and enlarged globe. Progression in neurologic deficits occurs in some patients, but this is quite variable. Mild cases with subtle imaging findings that are discovered later in childhood and with minimal symptoms have also been described.
46 - Optic Glioma
- from Section 2 - Sellar, Perisellar and Midline Lesions
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 95-96
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Summary
Specific Imaging Findings
Optic pathway gliomas (OPG) are found in the optic nerve, optic chiasm and optic tracts, with unilateral (most common) or bilateral distribution. They typically show fusiform enlargement of the optic pathway, which is iso- to hypodense on nonenhanced CT, T1 iso- to hypointense, and T2 iso- to hyperintense. Post-contrast enhancement varies from completely absent to intense. Kinking of the affected nerve and enlargement of the optic canal are frequently associated findings. OPG may show extension of neoplastic glial cells into the subarachnoid spaces with thickening and enhancement of the perioptic meninges, called “arachnoidal hyperplasia” or “arachnoidal gliomatosis”. This finding is almost exclusively seen in patients with neurofibromatosis type-1 (NF-1). On the other hand, cystic components seen as focal well-demarcated areas of hypointense T1 and hyperintense T2 signal are much more common in the sporadic OPG. Sporadic OPGs also tend to be larger, extend beyond the optic pathways, and progress over time. Extension of hyperintense T2 signal into adjacent tissue, especially hypothalamus, is suggestive of invasion. The majority of the OPG are relatively benign tumors and spontaneous regression may occur, especially in association with NF-1. The enhancement pattern may change over time, appear and disappear, which is without clear clinical implications in NF-1 patients. Findings of relatively low myo-inositol levels on MR spectroscopy and of increased permeability on perfusion imaging are suggestive of more aggressive neoplasms.
155 - Non-Hemorrhagic Metastases
- from Section 6 - Primarily Intra-Axial Masses
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 321-322
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Summary
Specific Imaging Finding
Metastatic neoplasms to the brain can occur anywhere; however, most are found at the supratentorial peripheral gray–white matter junction, followed by the cerebellum and basal ganglia. They are discrete, multiple or solitary masses, with variable degree of vasogenic edema in the surrounding white matter. The edema and mass effect are often very prominent and out of proportion to the lesion size except with cortical and very small metastases, where edema may be minimal. A majority are hypodense on CT and of low T1 signal. Tumors with high nuclear/cytoplasm ratios or mucinous contents, such as adenocarcinomas, are CT hyperdense. Necrotic and cystic tumors are T2 hyperintense. Highly cellular tumors show iso- to hypointense signal, while mucinous contents and calcifications lead to very low T2 signal, typically seen with adenocarcinomas. Non-hemorrhagic metastases always enhance with contrast, either in a nodular or ring-like pattern, typically with irregular but sharp margins. Volumetric T1WI improves detection of punctate deposits without edema. Metastatic tumors show variable MRI diffusivity characteristics. However, the center of ring-enhancing lesions is characteristically dark on DWI and bright on ADC maps, consistent with high diffusivity, with very rare exceptions. Perfusion studies reveal increased rCBV of the enhancing tumor, with delayed signal recovery on the signal intensity–time curve, in contrast to normal brain and gliomas. MRS shows nonspecific increased choline and decreased NAA levels. Both the MRS spectra and rCBV are essentially normal in the adjacent non-enhancing edema.
36 - Remote Cerebellar Hemorrhage
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 73-74
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Summary
Specific Imaging Findings
Remote cerebellar hemorrhage (RCH) typically occurs bilaterally along the superior aspect of the cerebellum following the cerebellar folia in a linear arched pattern that has been termed “zebra sign”. A recent RCH is seen as multiple linear hyperdensities on non-enhanced CT images. The same striped pattern is found on MRI, and it follows the signal intensity characteristics that vary according to the age of hemorrhage. The susceptibility effect from blood products is seen as signal loss on T2* MR sequences, gradient echo (GRE) or susceptibility-weighted images (SWI). Unilateral RCH is infrequent. Vascular studies, CTA, MRA, or DSA, reveal intact appearance of the venous sinuses and other vascular structures, without signs of thrombosis.
Pertinent Clinical Information
RCH is a rare complication of cranial and spinal surgeries that include opening of the dura. It has been reported following a wide range of procedures, from laminectomies and lumbar CSF drainages to temporal lobectomies, vascular neurosurgery, supratentorial tumor resections, and even single burr hole drainages. The most common symptoms are decreased level of consciousness, headache, nausea, and dizziness. The onset of symptoms is in the range from a few hours to a number of days after the surgical procedure. RCH is frequently benign and self-limited, but it may entail significant morbidity and result in death.
74 - Atretic Parietal Encephalocele
- from Section 2 - Sellar, Perisellar and Midline Lesions
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 151-152
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Summary
Specific Imaging Findings
Atretic parietal encephaloceles (APE) are located at the midline superior to the posterior fontanel. Non-enhanced CT images show a sharply marginated central calvarial defect (cranium bifidum) with associated extracranial soft tissue mass located under the scalp. Small cranium bifidum may only be seen with thin slices and 3D reconstructions. MRI shows an extracranial/subscalp mass just above the lambda with heterogeneous T1 signal intensity and hyperintense T2 signal. The APE may insinuate intracranially or show a fibrous band extending into the cranium bifidum. There is embryonic vertical positioning of the straight sinus, which is seen as a flow void connecting the vein of Galen with the superior sagittal sinus (SSS). There may be a “cigarshaped” CSF tract within the interhemispheric fissure and fenestration of the SSS. The lower posterior aspect of the SSS shows a bifid configuration, best appreciated on axial or coronal T2WI. The tentorium is displaced upward with a large superior cerebellar cistern and prominent suprapineal recess of the third ventricle, giving a “spinning-top” configuration to the tentorial incisura. Variations of occipital cortical infolding may be present. The position of the dural venous sinuses with respect to the encephalocele is best seen on post contrast images. APE can be associated with other anomalies, such as callosal dysgenesis, heterotopia, Dandy–Walker syndrome, Walker–Walburg syndrome, and holoprosencephaly. Persistent falcine venous sinus (horizontally connecting the vein of Galen with the SSS) and parietal foramina (persistent bilateral symmetric calvarial defects) may be the only findings in individuals with incidentally found APE.
71 - Corpus Callosum Dysgenesis
- from Section 2 - Sellar, Perisellar and Midline Lesions
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 145-146
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Summary
Specific Imaging Findings
Callosal dysgenesis (CD) is a spectrum of congenital defects of the corpus callosum (CC), which can be complete or partial. In complete CD, the CC, hippocampal commissure, and in half of the cases the anterior commissure are absent. In partial CD, the anterior commissure is always present as well as portions of CC. Multiplanar MR imaging is necessary to assess the CD abnormalities. With complete CC agenesis the morphology of the lateral ventricles is modified, as they become widely separated and lose the medially converging configuration, assuming an abnormal parallel appearance. The occipital horns are also enlarged. The interhemispheric fissure extends downwards to the roof of the third ventricle, which bulges upward. The midline cortical pattern is altered with the cingulate gyrus appearing absent and radially arrayed gyri converging to the roof of the third ventricle. The parietal and occipital sulci are shallow, and the hippocampi show round configuration. A parallel bundle of parasagittal white matter tracts is seen in the medial superior aspect of the lateral ventricles with relatively high T1 and low T2 signal intensity (bundle of Probst). On coronal images the constellation of findings leads to “trident” or “Viking helmet” appearance. Associated other abnormalities are frequently found with CD (in about three-quarters of cases), the most common ones being lipoma, interhemispheric cyst, and cortical dysplasia.
156 - Cerebral Abscess
- from Section 6 - Primarily Intra-Axial Masses
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 323-324
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Summary
Specific Imaging Findings
Cerebral abscess can occur in any part of the brain, but has a predilection for the supratentorial gray–white matter junction of the frontal and parietal lobes. On CT it typically presents as a subcortical area of prominent hypodense vasogenic edema with mass effect and a central rounded lesion of even lower attenuation, at times with a thin isodense rim, which shows enhancement on post-contrast images. The central portion of an abscess is of low T1 and high T2 signal (slightly brighter than the CSF). The capsule is characteristically T1 hyperintense and T2 hypointense with marked contrast enhancement. The rim enhancement is generally thin and smooth, especially on the outer side. Abscesses tend to expand medially becoming oval in shape, the capsule may accordingly be thinner toward the ventricles and thicker toward the cortex. Diffusion MR imaging is the most accurate imaging technique to differentiate bacterial abscess from other intracranial cystic/necrotic masses. In addition to hyperintensity on FLAIR and T1WI, the abscess center is very bright on DWI and dark on ADC, reflecting reduced diffusivity within the purulent material. Fungal abscesses may be more heterogenous, show higher ADC values, and involve the deep gray matter. MR spectroscopy shows complex spectra within abscesses with multiple abnormal peaks including lactate and lipids, as well as acetate, succinate, and amino acids. Perfusion studies, similar to other inflammatory and infectious processes, typically show decreased to normal cerebral blood volume.
143 - Epidermoid
- from Section 5 - Primarily Extra-Axial Focal Space-Occupying Lesions
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 295-296
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Summary
Specific Imaging Findings
Epidermoid (epidermoid cyst, cholesteatoma) is typically a non-enhancing extra-axial intradural mass. Epidermoids are lobulated space-occupying lesions that insinuate through subarachnoid spaces displacing and engulfing adjacent structures, primarily cranial nerves and arteries. They are typically isodense to slightly hyperdense to the CSF on CT. Rare variants may show calcifications and/or hyperdense contents (“dense epidermoid”). Epidermoids are iso- to slightly hyperintense to CSF on T1WI and with CSF-like hyperintensity on T2WI. These neoplasms do not enhance with contrast. FLAIR and especially DWI are the imaging techniques of choice. FLAIR images show internal “dirty” heterogeneity with signal intensity generally similar to the brain parenchyma. DWI reveals their striking hyperintensity, while the ADC values are similar to the brain. A small number of epidermoids may show high T1 and even low T2 signal, due to proteinaceous contents. This T1 hyperintensity is not suppressed on images with fat saturation pulse. Intra-axial and intradiploic skull lesions are much less frequent. The most common locations are cerebellopontine angle, pineal region, parasellar areas, and middle cranial fossa.
Pertinent Clinical Information
Epidermoids are usually silent until the third or fourth decade of life. Clinical presentation depends on the location and includes cranial nerve deficits, hydrocephalus, neuroendocrine symptoms, and seizures (with middle cranial fossa tumors). Surgical resection is curative. Chemical meningitis caused by cyst rupture is a possible complication, which very rarely follows dissemination of the cyst contents.
62 - Tectal Glioma
- from Section 2 - Sellar, Perisellar and Midline Lesions
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- By Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 127-128
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Summary
Specific Imaging Findings
Tectal gliomas (TGs) are located in the tectum of the midbrain, which includes superior and inferior colliculi as well as periaqueductal gray matter. TGs expand the tectum and typically show iso-to low density and signal intensity when compared to the gray matter on non-contrast head CT and T1-weighted MR images. They are usually of increased T2 signal and diffusion. Post-contrast enhancement may be present, but this is not a common finding. The expansion of the tectum can be associated with stenosis or obstruction of the aqueduct and consequent hydrocephalus. Cystic component, calcifications, exophytic growth and tumor extension in the adjacent structures, primarily thalamus, may also occur. Displacement of the aqueduct is a common feature. Tumor size has been reported as a prognostic factor and should be assessed.
Pertinent Clinical Information
TGs are indolent tumors that usually become symptomatic in childhood. The most common presentation is headache and papilledema, which is related to hydrocephalus and resolves after ventricular shunting or ventriculostomy, the most common and essential clinical intervention. Other possible symptoms are Parinaud syndrome, nystagmus, sixth nerve palsy and dysmetria. The large majority of the TGs are low-grade and indolent, while a few show more aggressive growth and an infiltrating pattern, and high-grade gliomas are rare.
175 - Hemangioblastoma
- from Section 6 - Primarily Intra-Axial Masses
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- By Zoran Rumboldt, Medical University of South Carolina, Maria Gisele Matheus, Department of Radiology and Radiological Science, Charleston, SC
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 08 November 2012, pp 361-362
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Summary
Specific Imaging Findings
Hemangioblastomas are typically located along the cerebellar surface and their classic appearance is a cystic mass with a mural nodule; however, solid masses with or without internal cysts are frequently encountered. The lesions are spherical and sharply demarcated, with the cystic component being usually CT hypodense, of very low T1 and high T2 signal. The signal of the cyst may vary, based on the protein content, and hemorrhage may be present. The solid tumor is T2 hyperintense and typically abuts the surface of the cerebellum and markedly enhances with contrast, whereas the cystic wall does not enhance. There is moderate to marked surrounding edema. Characteristic vascular flow-voids on MRI are present within larger lesions and best seen on T2WI. Solid portions have high diffusivity and are very bright on ADC maps. Perfusion studies reveal extremely high relative cerebral blood volume. While sporadic hemangioblastomas are found almost exclusively in the cerebellum, these tumors may occur anywhere throughout the CNS in patients with von Hippel–Lindau disease (VHL). The size of the lesion varies from punctate to several centimeters and post-contrast MR images are needed to detect small lesions. Catheter angiography of some hemangioblastomas shows characteristic tightly packed wide vessels and a nodule in the early arterial phase, resembling a “cherry attached to its stalk”. The constellation of MRI findings including intralesional flow-voids, contrast enhancement, increased diffusivity, and very high perfusion are diagnostic in most cases.
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