Are both color-flow duplex scanning and cerebral arteriography required prior to carotid endarterectomy?

In an attempt to eliminate the morbidity, mortality, and cost associated with arteriography, surgeons are relying increasingly on duplex scanning of the extracranial arteries as the primary preoperative evaluation prior to carotid endarterectomy (CEA). This study was initiated to evaluate the need for cerebral arteriography in the preoperative evaluation of patients for CEA. One hundred five patients undergoing 114 CEA procedures are included in a retrospective review to determine whether the addition of cerebral arteriography changed the operative management of these patients.

The effect of patient positioning on MR imaging of the internal auditory canal.

Identification of individual cranial nerves and complete exclusion of tumor in the internal auditory canal may be difficult with MR, especially in imperfectly positioned patients. MR studies of the temporal bones in patients and in normal volunteers positioned non-rotated or canted were correlated with corresponding cryomicrotomic sections. Especially in axial images, oblique sectioning of cranial nerves VII and VIII may cause difficulty in identifying individual nerves.

"Truncation" artifact in MR images of the internal auditory canal.

Dry skulls and a phantom were studied to determine whether an intracanalicular dark band in MR images of some acoustic neuromas could be artifactual. A "truncation" artifact was detected in the internal auditory canals of the dry skulls and in a simulated internal auditory canal of the phantom when the width of the canal approximately equaled 4 X (field of view) /N, where N equals 128 or 256, depending on the number of gradient steps chosen. The "truncation" artifact should not be confused with CSF between normal nerves when a canal contains tumor.

Differentiation of intramedullary neoplasms and cysts by MR.

To determine the MR criteria that are effective for differentiating intramedullary neoplasms from syringo- or hydromyelia, we reviewed MR scans made on prototype and commercial imagers of 33 patients with surgically confirmed cord abnormalities, including nine intramedullary neoplasms and 20 cysts (syringo- or hydromyelia). Two radiologists who did not know the clinical and radiologic diagnoses were asked to evaluate the scans with respect to cord expansion, distinctness of the disease margin, homogeneity, and signal intensity. These observations were correlated with the proved diagnoses.