A method to measure the extent of myocardial ischemia and steal with SPECT myocardial blood flow quantitation.

OBJECTIVE: We introduced a method to measure the extent of myocardial ischemia and steal with SPECT MBF quantitation. METHODS: Eighty-seven patients who received rest/Dipyridamole-stress 99mTc-Sestamibi (MIBI) dynamic SPECT scans and coronary angiography were included. Dynamic SPECT images were reconstructed with full physical corrections. The one-tissue kinetic model was utilized to quantify K1 and further converted to MBF with required corrections. Rest MBF, stress MBF and myocardial flow reserve (MFR) were converted to a flow status polar map by a flow diagram. Extents of 7 flow statuses were verified their cutoff points for detecting stenoses. The diagnostic performance (DP) was compared to that of MFR. RESULTS: Cutoff point of the extent to detect ≥ 50% stenosis was 3.01% for ischemia-steal status and 20.3% for the combined status of ischemia-steal and moderate. Using these criteria, sensitivity, specificity and accuracy to detect ≥ 50% stenosis were (80%, 75%, 79%) and (86%, 68%, 80%) for ≥ 70% stenosis. The DP was superior to that of MFR < 2.0 criterion (≥ 50%: 70%, 63%, 69%; ≥ 70%: 73%, 61%, 69%) (all p < 0.015). CONCLUSION: SPECT MBF quantitation integrated with the flow diagram can measure the extent of myocardial ischemia and steal which appeared more accurate to detect angiographic stenoses than the single MFR parameter.

Noninvasive Nuclear SPECT Myocardial Blood Flow Quantitation to Guide Management for Coronary Artery Disease.

Recently, myocardial blood flow quantitation with dynamic SPECT has been validated to enhance the detection of multivessel coronary artery disease (CAD) and conclude equivocal SPECT myocardial perfusion study. This advance opened an important clinical application to utilize the tool in guiding CAD management for area where myocardial perfusion tracers for PET are unavailable or unaffordable. We present a clinical patient with ongoing recursive angina who underwent multiple nuclear stress tests for a sequence of CAD evaluation in 26 months and demonstrated that SPECT myocardial blood flow quantitation properly guided CAD management to warrant patient outcome.

Improved hyponatremia after pericardial drainage in patients suffering from cardiac tamponade.

BACKGROUND: Some case reports showed unexplained hyponatremia in patients with cardiac tamponade. Reversible hyponatremia was observed in these patients who received pericardial drainage. The occurrence rate of hyponatremia in patients of cardiac tamponade is not clearly known. The objective of this study was to identify the relationship between hyponatremia, cardiac tamponade and their underlying diseases. METHODS: We reviewed the clinical data of patients with cardiac tamponade and receiving pericardial drainage between January 2000 and January 2012 in our hospital. Cardiac tamponade was diagnosed by clinical presentation: hypotension, pulsus paradoxus, and increased jugular vein pressure. We used paired T test to compare the sodium change before and after pericardial drainage. Pearson's chi-square test was used to analyze the relationship of hyponatremia with malignancy and cardiac chamber compression proved by echocardiography. RESULTS: For the 48 patients, the mean pre-drainage sodium level was 129.1 ± 7.1 mEq/L and the mean post-drainage sodium level was 130.4 ± 5.6 mEq/L (p = 0.06). Among the 48 patients, 31 (65 %) had hyponatremia. For the 31 hyponatremia patients, the mean pre-drainage sodium level was 124.8 ± 4.9 mEq/L and the mean post drainage sodium level was 127.5 ± 4.5 mEq/L (p = 0.003). Hyponatremia was significantly associated with malignancy (p = 0.038). There was no significant change of pre-drainage and post-drainage sodium level in patients without malignancy. The post-drainage sodium level in the malignant patients significantly increased from 125.5 ± 8.0 to 129.1 ± 5.5 mEq/L (p = 0.017). The presence of hyponatremia was strongly associated with the cardiac tamponade sign (p < 0.001). After pericardial drainage, the sodium level significantly increased in patients with chamber compression than in patients without compression. CONCLUSION: Hyponatremia is associated with cardiac tamponade especially for malignant pericardial effusion and for patients with cardiac chambers compression signs. Hyponatremia can be improved after pericardial effusion drainage.