SPECT imaging in cerebral vasospasm following subarachnoid hemorrhage.

UNLABELLED: Cerebral vasospasm is a frequent complication after subarachnoid hemorrhage and contributes to overall morbidity and mortality. Arteriography is the standard test for determining the presence of vasospasm. A retrospective review of 16 patients with cerebral aneurysm was undertaken to assess the sensitivity and specificity of SPECT for diagnosis of vasospasm. Fourteen patients were hospitalized after subarachnoid hemorrhage and 2 patients were hospitalized for elective aneurysmal clipping. The patients' condition on discharge was correlated to clinical and SPECT evidence of vasospasm. METHODS: Vasospasm was defined as the new onset of neurological signs and symptoms not explained by rebleed or hydrocephalus. A total of 20 SPECT studies were performed for 16 patients during their admission and 14 of 16 patients had a single angiographic study. RESULTS: Thirteen of 16 patients had 14 episodes of clinical evidence of vasospasm and 14 SPECT studies were performed in these 13 patients. The sensitivity and specificity of SPECT in this retrospective study were 89% (8/9) and 71% (5/7), respectively. Our small sample of arteriograms yielded in comparison a sensitivity of 67% (2/3) and specificity of 100% (9/9). The one false-negative SPECT study occurred in conjunction with the one false-negative arteriogram in the presence of clinical findings consistent with vasospasm. Three false-positive SPECT studies occurred in 2 patients who had perfusion abnormalities in areas of normal CT findings without clinical or arteriographic evidence of vasospasm. Five of 5 patients who died became unresponsive as a result of clinically presumed vasospasm and 4 of 5 of these patients had diffuse or hemispheric SPECT perfusion defects. Of the 11 patients who survived, none became unresponsive; 1 of 11 had positive diffuse or hemispheric perfusion defects. CONCLUSION: SPECT is a sensitive and fairly specific test for corroboration of clinical findings of vasospasm. A negative SPECT study may obviate the need for arteriography. Unresponsiveness is the best predictor of poor outcome; however, hemispheric SPECT perfusion deficits are also associated with poor outcome.

Scintigraphic functional hyposplenism in amyloidosis.

UNLABELLED: Functional asplenia or hyposplenism may predispose patients to spontaneous splenic rupture and potentially increase the risk of serious infection. In addition, hyposplenism may be a marker of more extensive systemic amyloidosis and has been correlated to a reduction in survival. Decreased splenic function is generally diagnosed by the presence of abnormal red blood cell morphology and decreased splenic uptake on 99mTc-sulfur colloid or microlite scans. We compared liver spleen scans with red cell morphology and anatomic imaging results in all patients with biopsy-proven amyloidosis who presented to the nuclear medicine department over a 12-yr period. Patients were referred from a center for amyloid disease for work-up of suspected hepatic involvement. METHODS: Between 1983 and 1995, 23 liver spleen scans from 21 patients (one patient had three scans) with known amyloidosis were referred for the assessment of degree of hepatic involvement with amyloid. All scans were retrospectively reviewed, and the degree of splenic uptake was graded. Medical records were reviewed for evidence of splenomegaly on physical exam. Extent of splenic involvement also was assessed by anatomical imaging (CT or MRI) in 45% of cases. Peripheral smear reports were reviewed for the presence of abnormal red cell morphology consistent with hyposplenism. RESULTS: Splenic activity was moderately or markedly reduced in 22 of 23 liver spleen scans (21 patients). Eight of these scans had correlative anatomic splenic imaging: four were abnormal and four were normal. Forty-one percent of available peripheral smears contained abnormal red cell morphology. Nine patients had palpable splenomegaly at the time of the liver spleen scan. Splenic pathologic studies were available for three patients (two autopsy, one surgical) and demonstrated diffuse splenic infiltration with amyloidosis. One patient had spontaneous splenic rupture. Fourteen patients died, four of overwhelming infection. CONCLUSION: Reduced splenic uptake on liver spleen scans for patients with suspected hepatic infiltration with amyloid is a common finding. Liver spleen scanning appears to be a more sensitive marker of splenic amyloidosis than clinical parameters or anatomical imaging.

Diagnosis of postoperative urinary ascites using renal scintigraphy.

Nuclear medicine biliary studies have been routinely used to identify bile leaks that occur after laparoscopic cholecystecomy. The use of a Tc-99m mercaptoacetyltriglycine (MAG3) renal scan to diagnose a case of urinary leakage that occurred after a laparoscopic-assisted colectomy is shown in this report. Laparoscopic surgery is widely used in place of conventional laparotomy to minimize recovery time and discomfort after surgery. The complication rate for laparoscopic colectomy has been reported as approximately 6% to 10%. In particular, ureteral leak has been reported in 2% of procedures. Ascites of unknown origin can become a diagnostic dilemma. We present a case of postoperative ascites of unknown origin that was successfully diagnosed as urinary leakage using renal scintigraphy.

Bone marrow suppression after strontium-89 therapy and local radiation therapy in patients with diffuse marrow involvement.

Strontium-89 is routinely used for pain control in advanced skeletal metastatic disease. A common side effect of Sr-89 therapy is a mild to moderate bone marrow suppression. To avoid complications from marrow suppression, a pretreatment platelet count of > 60,000/mm3 and a WBC count of > 2,400/mm3 are suggested. The authors present two patients who, despite satisfying these criteria, developed profound and prolonged bone marrow suppression after therapy. The severity of this response was most likely caused by pre-existing extensive bone marrow replacement with tumor. The contribution of local radiation therapy to bone marrow suppression is presumed to be minimal. The authors recommend that pretreatment criteria for determination of eligibility for Sr-89 therapy in selected patients be expanded to include steadily decreasing blood counts, and evaluation of extent of marrow involvement by biopsy or MR imaging.

Evidence of cortical metabolic dysfunction in early Huntington's disease by single-photon-emission computed tomography.

We compared perfusion of prefrontal, motor, and sensory cortices and basal ganglia in 29 Huntington's disease (HD) patients and nine controls. We found a significant reduction in perfusion in patients with HD of short (< 6 years, n = 10), medium (6-10 years, n = 8), and long duration (> 10 years, n = 11) compared with controls. Among short-duration patients, we observed decreases in cortical perfusion before evidence of atrophy on magnetic resonance imaging, suggesting that decreases in neuronal activity, as reflected by perfusion levels, precede gross structural changes. As expected, decreased perfusion was marked in basal ganglia. The extent of cortical perfusion correlated with clinical assessments of functional capabilities as well as with the duration of disease. Prefrontal perfusion correlated with cognitive measures, and motor cortical perfusion correlated with physical disability and activities of daily living scores. We found no significant clinical correlations with sensory cortical perfusion. Single-photon-emission computed tomography may be a sensitive method for assessing disease progression in clinical trials and pharmacologic intervention.

Stability of values for thyroid radioiodine uptake.

UNLABELLED: Chronological changes in values for thyroid radioiodine uptake measurements (RIU) have been reported in the last four decades. These changes are attributed to geographical and chronological variations in dietary iodine intake in the population. Fluctuations in normal values for RIU can affect the interpretation of these diagnostic tests in patients. METHODS: During the last 16 yr, thyroid RIU measurements using 123I were obtained in 671 euthyroid patients and 274 hyperthyroid patients, of which 233 patients had a diffuse goiter and 41 patients had a nodular goiter. RIU was measured 24 hr after the oral administration of 123I, 3.7-7.4 MBq (0.1-0.2 mCi) with no changes in technique during this period. Values (mean +/- s.d.) for RIU were calculated for various groups of patients for each year. Combined data for 1979-83 and 1988-94 were compared. Differences between mean values for each year were determined by a one-way ANOVA and pairwise comparison. RESULTS: For euthyroid patients, there were no significant differences in the mean and range of values from year to year. Additionally, there were no significant differences between the combined values for the earlier years (1979-83) and the later years (1988-94) for hyperthyroid patients. Minor statistical variations in the yearly values for the hyperthyroid patients were evident but not clinically important. CONCLUSION: Values for thyroid uptake of 123I in euthyroid and hyperthyroid patients in Boston have remained stable for the last 16 yr.