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Magnetic resonance imaging (MRI) appears to be superior to CT scanning in confirming the diagnosis of multiple sclerosis (MS). Both an MRI scan and a CT scan were used to assist with the diagnosis of 303 patients with suspected multiple sclerosis. Two neurologists read the scans without any previous knowledge of the patients' histories. The MRI scans established a diagnosis of MS in 60 patients and definitively ruled out a diagnosis of MS in 128. Ninety-five of the scans were interpreted as possible or probable MS and 20 were interpreted as probably not MS. MRI scans were clearly better than CT scans in assisting with diagnosis. Because MRI could not completely rule out MS, physicians and patients should not be falsely reassured by a negative MRI result, especially if the patient shows clinical signs of MS., Objective.--To design and implement a methodologically rigorous study to examine the accuracy of magnetic resonance imaging (MRI) in a patient population clinically suspected of having multiple sclerosis (MS). Design and Setting.--Three hundred three patients, who were referred to two university medical centers because of the suspicion of MS, underwent MRI of the head and double-dose, contrast-enhanced computed tomography (CT) of the head. The images were read by two observers individually and without knowledge of the clinical course or final diagnosis. Patients were followed up for at least 6 months and reevaluated clinically with subsequent neurological examination. Final diagnosis (MS or not MS) was made by a panel of neurologists on the basis of the clinical findings at presentation, those that developed during follow-up, and other diagnostic tests. The results of the imaging procedures were excluded to avoid incorporation bias. Diagnostic accuracy was assessed using receiver-operating characteristic analysis and likelihood ratios. Results.--Magnetic resonance imaging of the head was considerably more accurate than CT in diagnosing MS. The area under the receiver-operating characteristic curve for MS was 0.82 (compared with 0.52 for CT) indicating that MRI was a good but not definitively accurate test for MS. A "definite MS" reading on an MRI of the head was specific for MS (likelihood ratio, 24.9) and essentially established the diagnosis, especially in patients clinically designated as "probable MS" before testing. However, MRI of the head was negative for MS in 25% and equivocal in 40% of the patients considered to have MS by the diagnostic review committee (sensitivity, 58%). Conclusions.--Magnetic resonance imaging of the head provided assistance in the diagnosis of MS when lesions were visualized. Its ability far exceeded imaging with double-contrast CT. The sensitivity and, therefore, the predictive value of a negative MRI result for MS were, however, not sufficiently high for a normal MRI to be used to conclusively exclude the diagnosis of MS.

Modern techniques of medical imaging may produce astounding pictures of the body and its functions, but such images are not necessarily any better for purposes of diagnosis than those produced by more conventional techniques. The true value of any imaging technique can only be established by careful experimental evaluation. Just such an evaluation has been performed to compare two techniques of magnetic resonance imaging (MRI) with conventional angiography (X-ray of the blood vessels) for the examination of the carotid artery. Since angiography is an invasive technique requiring the insertion of catheter, MRI might be a significant improvement if its capabilities are also comparable. Stenosis, or narrowing, of the carotid artery carrying blood to the head is a major risk factor for stroke, and observation of this stenosis may lead to potentially preventive measures. The carotid bifurcations, where the carotid artery splits into the internal and external carotid arteries, were evaluated in 31 patients in whom carotid artery disease was suspected. The results provided by the established technique of invasive angiography were accepted as the correct diagnosis for purposes of comparison. Overall, the sensitivity of the MRI methods was 86 percent, meaning that 86 percent of the carotid artery abnormalities were actually detected by the MRI techniques. The specificity of the MRI methods was 92 percent, indicating that a negative indication by MRI will be right about 92 percent of the time. While these figures are close to the range which may make MRI suitable, it was also found that the errors which did occur happened because of difficulties experienced in the interpretation of the image, not the image quality. Furthermore, the physicians who read the images felt confident of their interpretations for 74 percent of the angiograms but for only 28 percent of the MR images. The MR images were apparently more difficult to read, and took 15 to 20 minutes, compared to the five minutes required to interpret a conventional angiogram. It would be advantageous to be able to use a noninvasive technique such as MRI for the evaluation of carotid stenosis, and, indeed, improvements in MRI technology may bring this to pass. At present, however, any adoption of the MRI technique for this purpose should be only with great care and strict adherence to evaluation methodology. (Consumer Summary produced by Reliance Medical Information, Inc.)

Magnetic resonance (MR) imaging has quickly emerged and already replaced computerized tomography (CT) in the evaluation of cerebellopontine angle (CPA) lesions, although even MR scanning may occasionally yield equivocal results. We recently studied six patients with a new MR image-enhancing contrast, gado-linium-DTPA (Gd-DTPA). All patients were suspected of having CPA pathology, and the standard MR scan was either negative, equivocal, or left unanswered questions regarding confirmed lesions. The Gd-DTPA-enhanced MR scan confirmed tumors or added useful information in five of six patients. [ABSTRACT FROM AUTHOR]

The localization of a cerebrospinal fluid fistula producing cerebrospinal fluid otorrhea can be very difficult. However, the exact anatomic localization of the bony defect is important when selecting the surgical approach to repair. Case reports of two patients in whom spontaneous cerebrospinal fluid otorrhea occurred following pressure equalization tube placement for middle-ear effusion are presented. Nuclear magnetic imaging supplemented CT scan findings, providing noninvasive localization of the defect. Preoperative impressions were confirmed at surgery. In addition to discussing the use of magnetic resonance imaging in evaluating cerebrospinal fluid otorrhea, the literature will also be reviewed. [ABSTRACT FROM AUTHOR]