The radiologic findings in three cases of meningovascular syphilis are presented. Angiography demonstrated varying degrees of narrowing and ectasia of the supraclinoid carotid, basilar, and proximal anterior and middle cerebral arteries, as well as distal branches. Computed tomography (CT) showed multifocal infarction with variable enhancement. Similarly, in the one case studied with magnetic resonance (MR), several regions of high signal intensity on T2-weighted sequences were found, which were compatible with foci of ischemia. Although the radiologic findings are nonspecific, the diagnosis of meningovascular syphilis should be considered in patients with vasculitis of uncertain etiology.
The emergence of multiplanar spiral computed tomography and high-resolution magnetic resonance imaging has resulted in the ability to see cervical spine anatomy and pathologic conditions in detail. Appropriately chosen and performed, these imaging studies can provide an anatomic basis for a clinical diagnosis and a therapeutic plan. In the evaluation of cervical spondylosis, magnetic resonance imaging is more commonly performed than computed tomography because of its superior depiction of soft tissue anatomy, including intervertebral discs and spinal cord disease. However, computed tomography still has a role, particularly in the assessment of osseous neural foraminal stenosis. In cervical spine trauma, routine radiography remains the procedure of choice. Computed tomography is performed in patients who have abnormal plain radiographs or in patients in whom there is a strong clinical suspicion of fracture with inconclusive radiographs. In the neurologically compromised patient, magnetic resonance imaging is useful in the diagnosis of cord and nerve root injury. Magnetic resonance imaging is the most sensitive and specific imaging study in the assessment of spinal infection, including osteomyelitis, discitis, and epidural abscess. Magnetic resonance imaging has also supplanted all other imaging methods in the evaluation of primary and secondary tumors of the spinal cord and spinal column. Despite the precise depiction of cervical spine anatomy provided by these imaging methods, the role of the clinician in determining the true cause of a patient's symptoms is in no way diminished. The presence of an imaging study abnormality does not automatically imply causality.
Fifty calcified intracranial lesions diagnosed with computed tomography (CT) were evaluated with magnetic resonance (MR) using a spin-echo sequence. MR images demonstrated 41 of 50 lesions seen as calcified on CT scans, among them 29 of 30 cerebral neoplasms and all ten arteriovenous malformations. The presence of calcification was suspected prospectively in about 60% of calcified lesions but was also suspected in 45% of uncalcified lesions (reviewed as control cases). No fine calcifications and only 25% of punctate calcifications were disclosed on MR images. In the nine lesions undetected by MR, calcification was the only abnormal CT finding. The findings of calcification on MR images were nonspecific, ranging from signal void or signal dampening on all sequences to no alteration of signal intensity. The most common finding of calcification was a focus of signal diminution, rather than signal void, as commonly reported.
Impairments in language and communication are core features of Autism Spectrum Disorder (ASD), and a substantial percentage of children with ASD do not develop speech. ASD is often characterized as a disorder of brain connectivity, and a number of studies have identified white matter impairments in affected individuals. The current study investigated white matter integrity in the speech network of high-functioning adults with ASD. Diffusion tensor imaging (DTI) scans were collected from 18 participants with ASD and 18 neurotypical participants. Probabilistic tractography was used to estimate the connection strength between ventral premotor cortex (vPMC), a cortical region responsible for speech motor planning, and five other cortical regions in the network of areas involved in speech production. We found a weaker connection between the left vPMC and the supplementary motor area in the ASD group. This pathway has been hypothesized to underlie the initiation of speech motor programs. Our results indicate that a key pathway in the speech production network is impaired in ASD, and that this impairment can occur even in the presence of normal language abilities. Therapies that result in normalization of this pathway may hold particular promise for improving speech output in ASD.
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