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Background and Purpose: The "ears of the lynx" MR imaging sign has been described in case reports of hereditary spastic paraplegia with a thin corpus callosum, mostly associated with mutations in the spatacsin vesicle trafficking associated gene, causing Spastic Paraplegia type 11 (SPG11). This sign corresponds to long T1 and T2 values in the forceps minor of the corpus callosum, which appears hyperintense on FLAIR and hypointense on T1-weighted images. Our purpose was to determine the sensitivity and specificity of the ears of the lynx MR imaging sign for genetic cases compared with common potential mimics., Materials and Methods: Four independent raters, blinded to the diagnosis, determined whether the ears of the lynx sign was present in each of a set of 204 single anonymized FLAIR and T1-weighted MR images from 34 patients with causal mutations associated with SPG11 or Spastic Paraplegia type 15 (SPG15). 34 healthy controls, and 34 patients with multiple sclerosis., Results: The interrater reliability for FLAIR images was substantial (Cohen κ, 0.66-0.77). For these images, the sensitivity of the ears of the lynx sign across raters ranged from 78.8 to 97.0 and the specificity ranged from 90.9 to 100. The accuracy of the sign, measured by area under the receiver operating characteristic curve, ranged from very good (87.1) to excellent (93.9)., Conclusions: The ears of the lynx sign on FLAIR MR imaging is highly specific for the most common genetic subtypes of hereditary spastic paraplegia with a thin corpus callosum. When this sign is present, there is a high likelihood of a genetic mutation, particularly associated with SPG11 or SPG15, even in the absence of a family history., (© 2019 by American Journal of Neuroradiology.)

Hemangioblastomas of the central nervous system are the most common tumors seen in patients with von Hippel-Lindau (VHL) disease. A very rare case of diffuse leptomeningeal hemangioblastomatosis obliterating large areas of the subarachnoid space, both intracranial and within the spinal canal, which developed during a relatively short period, in a patient with VHL disease is presented.

We describe two cases of pituitary involvement by Wegener's granulomatosis. At initial presentation, or during subsequent disease "flares," a pattern of pituitary abnormality was suggested. During periods of remission, we found the pituitary returned to a nearly normal appearance. Loss of the normal posterior pituitary T1 hyper-intensity matched a clinical persistence of diabetes insipidus, suggesting there is permanent damage to this structure by the initial disease process.

Purpose: To evaluate a slow-flow MR sequence in normal CSF flow and in CSF flow disturbance in cases of spinal stenosis., Method: The method was tested for flow sensitivity and applied to 67 sites of spinal canal compromise., Results: Phantom studies show that flow can be depicted at a velocity of 0.5-1 mm/sec. On clinical images, stagnant CSF is black, flowing CSF is bright. Typically, in high-grade (90%-100%) stenosis, CSF above and below the site of spinal canal compromise (SCC) is black. With intermediate stenosis (50%-89%), CSF above the SCC remains white but becomes black distal to the SCC. Low-grade stenosis shows only localized flow disturbances., Conclusion: This easy-to-use sequence can solidify the MR diagnosis of high-grade stenosis when a distinct flow pattern is recognized. Flow patterns for intermediate and low-grade stenosis are less reliable.

A comparison of the glycolytic rate as determined by positron emission tomography (PET) with 18F-deoxyglucose (FDG) and cerebral contrast computed tomography (CT) was carried out in 72 cases of cerebral glioma. FDG-PET is more accurate than contrast CT in predicting tumor grade.

This paper illustrates the clinical value of a computer technique for superimposition of two different kinds of imaging procedures. The initial application was to overlay cerebral angiograms onto computed tomograms of the brain. Case material from three patients with intracerebral abnormalities is presented. The sum of information from the combined studies exceeds that from either study alone and has value for both diagnosis and treatment of head lesions.

Subacute sclerosing panencephalitis is a progressive, frequently fatal slow virus infection of the brain attacking children and young adults and caused by measles virus. Computed tomography (CT) of the brain in 15 patients with this disease was normal in seven and abnormal in eight. CT demonstrated varying degrees of cortical atrophy associated with focal and multifocal low density lesions of the white matter. Two cases demonstrated low density lesions of the caudate nuclei. The CT lesions were seen in chronic cases and reflect the gliosis and atrophy that occur in this disease. Differential diagnoses include other viral infections and demyelinating and dysmyelinating diseases. Diagnostic laboratory evaluation includes serum and cerebrospinal fluid titers for measles antibodies, cerebrospinal fluid protein electrophoresis, electroencephalography, and cranial CT.

Twenty-four patients with ventricular septa are discussed. Seventeen patients had septa acquired during the neonatal period and seven exhibited septations at birth (cogenital septa). Among the acquired septa, there were true intraventricular septa and septa that originated outside the ventricles but later became part of the ventricular system (pseudosepta). Pseudosepta originate in necrotic, cavitating periventricular white matter that, in temporal sequence, becomes ventricularized. Serial use of cranial sonography provided important information about the pathologic mechanisms that govern the development of septa. Intraventricular hemorrhage and infection are the major causes of true intraventricular septa, while periventricular leukomalacia serves as primary cause of pseudosepta. Sonography is the diagnostic method of choice. Septa are associated with a high incidence (62%) of shunt failure.

Positron emission tomography (PET) scanning with [18F]-2-fluoro-2-deoxy-D-glucose (FDG) was used to study 59 patients with astrocytomas and three patients with other cerebral mass lesions. Suppression of gray-matter glucose utilization ranging from 8% to 64% (mean, 30%) was seen in 92% of cases. Three categories of suppression were apparent, with the greatest degrees of suppression occurring in edematous gray matter adjacent to mass lesions. Lesser degrees of suppression were noted in nonedematous structures (normal attenuation on computed tomographic scan) adjacent to the lesion. Significant suppression was also present in gray matter spatially remote from but functionally linked to the site of the lesion. This approach may become a useful tool for improved understanding of the clinical presentation of certain pathologic entities and for evaluation of disease progression and response to treatment.