sodium-pertechnetate-tc-99m and Multiple-Sclerosis

This study was undertaken to assess the contribution of the combination of (201)Tl SPECT and (99m)TcO(4)(-)SPECT to the differential diagnosis of brain tumors and tumor-like lesions. In the 8 patients selected for this study, both (201)Tl SPECT and (99m)TcO(4)(-) SPECT were performed because of clinical or radiological suspicion of brain tumor, no therapy was initiated before either SPECTs, diagnosis was based on biopsy, and MRI findings were stable in the interval between SPECTs. Histological diagnoses consisted of low grade glioma (n=1), high grade glioma (n=2), lymphoma (n=1), metastasis (n=1), multiple sclerosis (n=2) and cavernous angioma (n=1). Two high grade astrocytomas, one malignant lymphoma and one metastatic tumor showed (201)Tl accumulation and were diagnosed as tumor. The combination of (201)Tl and (99m)TcO(4)(-) did not change the diagnosis. One cavernous angioma showed no (201)Tl accumulation and was diagnosed as non-tumor. The combination of (201)Tl and (99m)TcO(4)(-) did not change the diagnosis. One low grade astrocytoma showed faint (201)Tl accumulation and was diagnosed as non-tumor. As (201)Tl uptake was higher than (99m)TcO(4)(-) uptake, the combination of (201)Tl and (99m)TcO(4)(-) changed the diagnosis to tumor. Two multiple sclerosis showed (201)Tl accumulation and were diagnosed as tumor. As (99m)TcO(4)(-) uptake was higher than (201)Tl uptake, the combination of (201)Tl and (99m)TcO(4)(-) changed the diagnosis to non-tumor. In three of the eight patients (38%), the combination of (201)Tl SPECT and (99m)TcO(4)(-) SPECT altered the diagnosis made by (201)Tl SPECT alone. In all of these three cases, the diagnosis made by the combination of (201)Tl SPECT and (99m)TcO(4)(-) SPECT was correct.

Topics: Brain; Brain Neoplasms; Diagnosis, Differential; Humans; Multiple Sclerosis; Retrospective Studies; Sensitivity and Specificity; Sodium Pertechnetate Tc 99m; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

We compared a prototype long-bore (LB) high-resolution collimator with a low-energy, general-purpose collimator (LEGP) using 99mTc and 123I. The LB collimator provided a 56% improvement in tomographic resolution (autocorrelation width) over the LEGP for 99mTc; for 123I, the gain was 79%, providing substantially improved contrast for small structures. The sensitivity of the LB collimator, however, is only 32% of that of the LEGP. The imaging tasks to be performed on [123I]IMP brain scans involve localization and discrimination of small, high-contrast brain structures and detection of abnormalities in shape, size, or uptake, rather than simple detection of lesions. Observer performance in such higher-order imaging tasks is known to depend on high spatial resolution, even at the cost of sensitivity. Patient studies confirmed that, for resolution-limited tasks, the increase in resolution outweighs the increased noise due to a loss in sensitivity. When the tomographic resolution of the LB collimator was degraded by smoothing to that of the LEGP, the noise in the LB images was lower than that of the LEGP by a factor of 2.9 for the same imaging time, demonstrating the advantage of high-resolution detectors and a smooth reconstruction filter over low-resolution detectors without smoothing. Therefore, collimators designed for high resolution, even at substantial cost in sensitivity, are expected to yield significant improvements for brain SPECT. Geometric calculations show that commercially available low-energy, high-resolution cast collimators promise to meet these requirements.

Topics: Amphetamines; Brain; Cerebrovascular Disorders; Humans; Iodine Radioisotopes; Multiple Sclerosis; Sodium Pertechnetate Tc 99m; Tomography, Emission-Computed

Periphlebitis retinae (PR) in multiple sclerosis (MS) is seen as transitory infiltrations around veins in the otherwise normal retina. Cellular infiltrations have been found around veins in the central nervous system (CNS), where it has been suggested that they are the first event in plaque formation. Technetium brain scans are usually normal in MS patients, but transitory abnormal scans of the cerebrum have been found in MS patients during acute attack or exacerbation. In order to test the hypothesis that active PR is a sign of simultaneous disease activity in the CNS, 29 technetium brain scans were carried out on 14 MS patients with active PR and on 15 MS patients without any signs of PR. Significantly more of the patients with active PR, compared with MS patients with previous PR, displayed abnormal brain scans. This indicates that a disruption of the blood brain barrier (BBB) and active PR occur simultaneously in MS.

Topics: Adolescent; Adult; Blood-Brain Barrier; Humans; Middle Aged; Multiple Sclerosis; Phlebitis; Radionuclide Imaging; Retinal Vein; Sodium Pertechnetate Tc 99m; Technetium