Aphasia after hemispherectomy in an adult with early onset epilepsy and hemiplegia.

A 55 year old left handed man with left hemisphere subcortical encephalomalacia, seizures, language impairment, and right hemiparesis from a motor vehicle accident at age five was evaluated for epilepsy surgery. The patient continued to speak and followed commands during a left intracarotid amobarbital test (IAT). Left functional hemispherectomy resulted in expressive aphasia. Based on postoperative outcome, language was bilateral. The injury after primary development of language function, the predominantly subcortical lesion, and the late timing of surgical intervention well past development and plasticity may have been factors in the emergence of postoperative aphasia.

Detection of clinically silent intracranial emboli ipsilateral to internal carotid occlusions during cerebral angiography.

OBJECTIVE: Embolic ischemic events have long been suspected to occur in the cerebral arteries distal to an ipsilateral occluded internal carotid artery (ICA). Documentation of microemboli by transcranial Doppler sonography during catheter angiography in patients with ICA occlusions provides objective evidence of such distal emboli. SUBJECTS AND METHODS: Seven patients undergoing carotid angiography were evaluated with transcranial Doppler sonography. Patients were also screened for ICA occlusions using carotid duplex sonography. In the seven patients, we saw five right ICA occlusions and two left ICA occlusions. Real-time visual and auditory confirmations of emboli were obtained by recognizing their specific spectral signatures and harmonic qualities. Routes of collateral flow were determined from angiography. Specific phases of the examination were correlated with embolic occurrences. RESULTS: Overall, emboli were seen during all phases of arteriography. In the individual patients, emboli were identified in one to four of the eight angiographic phases we defined. Most emboli occurred during catheter flushing and contrast injection rather than during wire and catheter manipulation. The emboli were detected in the middle cerebral artery distribution ipsilateral to the occluded ICA in all seven patients. Collateral flow patterns included, in four patients, external carotid artery-to-ICA collateral flow; in all seven patients, patent anterior communicating arteries; and in three patients, patent posterior communicating arteries. CONCLUSION: Emboli seen in middle cerebral arteries ipsilateral to occluded ICAs during cerebral angiography strongly indicate that emboli can occur distal to an occlusion. Our findings support the thought that emboli arising from sources proximal to an occluded ICA may reach the hemisphere distal to the occlusion, resulting in parenchymal ischemia or infarction.

MR imaging of spinal infections.

In the appropriate clinical situation, MR imaging is a powerful tool in the diagnosis of spinal infection. Imaging of spinal infections requires the use of a combination of T1-weighted and T2-weighted or STIR sequences. Contrast enhancement is useful and helps to define paraspinal and epidural disease. Knowledge of potential pitfalls with MR imaging and of normal marrow conversion is required. With these points in mind, MR imaging will be beneficial in the care of patients with spinal infections.

The role of transcranial Doppler in nonarteritic ischemic optic neuropathy.

PURPOSE: To investigate through the use of cerebral Doppler technology whether emboli are a more common cause of nonarteritic anterior ischemic optic neuropathy (NAION) than previously recognized. METHODS: Eleven patients with a recent (<121 days) history of nonarteritic anterior ischemic optic neuropathy and 10 age-matched controls (event > 121 days) were examined using a Nicolet Pioneer 2020 transcranial Doppler (TCD) unit with a 2-MHz bilateral continuous monitoring capability. The right and left middle cerebral arteries were evaluated simultaneously for 30 minutes at a depth of 50 to 55 mm, and the number of emboli, blood flow velocities, and pulsatility indices were recorded. Data were stored by computer, and hard-copy color recordings were made. RESULTS: None of 11 patients with a recent history of NAION demonstrated microemboli by TCD examination. One patient in the control group who had a remote history of NAION had a microembolic event rate of 12 per hour (six over 30 minutes). This patient had a history of prosthetic cardiac valve replacement and was taking anticoagulation medication at the time of the examination. CONCLUSIONS: Our study did not reveal an increased incidence of embolic events in patients with NAION when they were examined in a transcranial Doppler study of the middle cerebral arteries. This study does not support embolism as a frequent cause of NAION.

MR imaging of vertebral osteomyelitis revisited.

OBJECTIVE: The purpose of this study was to reevaluate previously reported MR imaging findings for vertebral osteomyelitis that include decreased signal intensity in the disk and adjacent vertebral bodies on T1-weighted images, increased signal intensity in the disk and adjacent vertebral bodies on T2-weighted images, loss of endplate definition on T1-weighted images, and contrast enhancement of the disk, adjacent vertebral bodies, and involved paraspinal and epidural soft tissues. MATERIALS AND METHODS: Medical records, radiographs, and MR scans of 37 patients with vertebral osteomyelitis with 41 levels of involvement were reviewed for agreement with reported MR imaging findings. RESULTS: Ninety-five percent of the levels (39/41) showed decreased vertebral body signal intensity on T1-weighted images; 95% (39/41) had loss of endplate definition; 95% (37/39) had increased disk signal intensity on T2-weighted images; and 56% (22/39) had increased vertebral body signal intensity on T2-weighted images. Eighty-five percent of the levels (35/41) and 84% of patients (31/37) had both signal intensity changes of the vertebral body on T1-weighted images and signal intensity changes of the disk on T1-and T2-weighted images. Only 46% of the levels (19/41) and 49% of patients (18/37) had both vertebral body and disk changes on T1- and T2-weighted images. Contrast enhancement of the disk and vertebral body was seen in 94% of patients (17/18). Ring enhancement of paraspinal and epidural processes was found to correlate at surgery with abscess, and homogeneous enhancement was found to correlate with phlegmon. CONCLUSION: Hypointense signal intensity in the vertebral body on T1-weighted images, abnormal disk signal intensity on both T1- and T2-weighted images, and contrast enhancement are the findings that indicate spinal infection most reliably.

High resolution, magnetization transfer saturation, variable flip angle, time-of-flight MRA in the detection of intracranial vascular stenoses.

OBJECTIVE: Factors that restrict 3D TOF MRA are limited resolution, saturation of flow, and degree of background suppression. We evaluated MRA for intracranial stenoses by using a 3D TOF technique that minimizes these factors. MATERIALS AND METHODS: Twenty-nine patients underwent MRA and intraarterial digital subtraction angiography (DSA). The MRA studies were performed on a 1.5 T Siemens SP 4000 system. Integrated techniques applied to the conventional 3D TOF acquisition included the following: (a) 256 x 256 matrix with a 140 mm FOV and 0.9 mm slice thickness, yielding a 0.54 x 0.54 x 0.9 mm3 voxel; (b) tilted optimized nonsaturating excitation (TONE); and (c) magnetization transfer saturation (MTS). The intraarterial DSA was performed on a Siemens Angiostar system with a 1,024 x 1,024 noninterpolated matrix. The MRAs were reviewed by two neuroradiologists. Two hundred seventy-seven vessels were evaluated for a total of 806 segments. Vessel segments were evaluated with a 5 point scale. RESULTS: The estimated accuracy of MRA for detecting stenosis over all intracranial vessel segments was 0.88 +/- 0.03 and 0.89 +/- 0.02 for the two readers, respectively. The estimated accuracy ranged from 0.94 +/- 0.02 and 0.93 +/- 0.02 for detecting internal carotid artery stenosis by the two readers, respectively, to 0.65 +/- 0.17 and 0.71 +/- 0.15 for detecting distal vertebral artery stenosis. In vessels determined by catheter angiography to be stenosis-free, reader confidence at the proximal versus distal segments was similar for the internal carotid, basilar, and posterior cerebral arteries. However, for the anterior and middle cerebral arteries, one or both readers were more confident in diagnosing the proximal segment. CONCLUSION: High resolution MTS TONE 3D TOF MRA is an accurate technique for the screening of medium and large vessel intracranial stenoses.

Silent cerebral microemboli occurring during carotid angiography: frequency as determined with Doppler sonography.

OBJECTIVE: The purpose of this study was to determine the frequency of occult cerebral embolic events during carotid angiography and the relationship of these events to different phases of the procedure. SUBJECTS AND METHODS: Fifteen patients undergoing carotid angiography were prospectively evaluated by using continuous transcranial Doppler monitoring. Realtime visual and auditory confirmations of emboli were accomplished by recognizing their specific spectral signature and harmonic quality. Specific phases of the examination, such as manipulation of the catheter and guidewire, flushing of the catheter, and injecting contrast material were documented and correlated with embolic occurrences. RESULTS: A total of 1100 embolic phenomena were detected in the middle cerebral artery during carotid angiography. Of these, 944 occurred during catheter flushing and injection of contrast material, and 156 occurred during catheter and wire manipulation. In each patient, more emboli occurred during catheter flushing and injection of contrast material than during manipulation of the catheter and guidewire. No gross neurologic sequelae occurred. CONCLUSION: Embolic phenomena occur frequently during all phases of uncomplicated cerebral angiography.

Late Greenfield filter vena cava perforation causing a small bowel obstruction: case report.

This report describes a symptomatic case of vena caval perforation caused by a vena cava filter. Functional small bowel obstruction due to vascular compromise was caused by a prong of the filter.