Effects of metabolic and myocardial microcirculatory abnormalities on the pathogenesis of cardiac autonomic neuropathy in type 2 diabetes mellitus: A prospective study in Japanese patients.

BACKGROUND: In diabetic patients, cardiac autonomic neuropathy is an important factor affecting prognosis. Whether this condition in diabetic patients is caused directly by neurovisceral metabolic disorder and/or indirectly by micro circulation remains to be clarified. OBJECTIVE: The aim of this study was to determine whether cardiac sympathetic nerve dysfunction can be detected using adenosine triphosphate (ATP) testing, while also investigating the effects of metabolic and/or myocardial microcirculatory abnormalities on the pathogenesis of cardiac autonomic nerve dysfunction in patients with type 2 diabetes mellitus (DM-2) in Japan. METHODS: This prospective study was performed at the Division of Diabetology Department of Internal Medicine, Toho University, Ohashi Hospital, Tokyo, Japan. Patients aged ≥ 18 years with DM-2 with no abnormalities on electrocardiography (ECG) or echocardiography were enrolled. An ATP thallium (Tl)-201 myocardial scintigraphy test (ATP test) and iodine (I)-123 metaiodobenzylguanidine (MIBG) scintigraphy were performed. ATP was administered by continuous IV infusion over 6 minutes at 0.16 mg/kg · min. Five minutes after the ATP infusion was started, T1-201 111 MBq IV was administered. Single-photon emission computed tomography (SPECT) imaging was begun immediately after the end of ATP infusion and was completed 3 hours after stress to show washout from stress to rest. I-123 MIBG 111 MBq IV was administered. A planar image from the front side and a SPECT image (early phase) was obtained 15 to 30 minutes later. After 3 hours, a planar image from the front side and a SPECT image (late phase) were obtained to show washout from stress to rest. The mean TI washout rate (ATP-WR) and heart-to-mediastinum (H/M) ratio in the late-phase scintigraphic images and the washout rate of MIBG (MIBG-WR) in the left ventricle was determined. The correlations of these measurements with the mean values of glycosylated hemoglobin (HbA1c) and fasting plasma glucose obtained from monthly measurements over the previous 6 and 24 months were determined. RESULTS: A total of 25 patients were enrolled (13 men, 12 women; mean [SD] age, 59.86 [8.28] years). Significant negative correlations between both ATP-WR and MIBG-WR and HbA1c were found (r = -0.52 [P = 0.02] and -0.47 [P = 0.03], respectively). Although no correlation was found between ATP-WR values and the early phase H/M ratio, a significant positive correlation was observed between ATP-WR and H/M ratio (r = 0.54; P = 0.02). CONCLUSIONS: In the present study in Japanese diabetic patients without subjective signs of coronary artery disease and without abnormalities on ECG or echocardiography, ATP-WR, an indicator of myocardial blood flow, was correlated with myocardial sympathetic nerve dysfunction and 24-month glycemic control. However, sympathetic nerve dysfunction was not correlated with 24-month glycemic control.

Comparison of Thallium-201 Scan and Tc-99m Sestamibi Scan in the Differential Diagnosis of Breast Mass / 대한핵의학회잡지

PURPOSE: We performed this study to compare T1-201 and Tc-99m MIBI scans for the differentiation of malignant from benign breast mass. MATERIALS AND METHODS: Thirty-eight female patients underwent T1-201 breast scan and thirty-two of them also underwent Tc-99m MIBI scan of the breast. After intravenous injection of 74-111 MBq of T1-201, early (10 minutes) and delayed (3 hours) images were obtained. Then, 555-740 MBq of Tc-99m MIBI was injected and images after 30 minutes were obtained. We compared T1-201 and Tc-99m MIBI scans with pathologic RESULTS. RESULTS: Twenty-three patients were confirmed to have infiltrating duct carcinoma and fifteen patients to have benign breast mass by excisonal biopsy. The sensitivity of early and delayed T1-201 scan and Tc-99m MIBI scan in the detection of malignant breast lesion were 100% (23/23), 82% (18/22), and 90% (18/20), respectively. The specificity of early T1-201 scan was significantly higher than that of delayed T1-201 scan (p<0.05). The specificity of early and delayed T1-201 scan and Tc-99m MIBI scan were 73% (11/15), 73% (11/15) and 83% (10/12), respectively (p:not significant). Three patients out of nine with fibroadenoma and one patient with atypical duct hyperplasia were false positive in both early and delayed T1-201 scans. The size of fibroadenoma with false positvie in early and delayed T1-201 scan (4 cases) was larger than that of 11 fibradenoma with true negative scan (p<0.01). Metastatic axillary lymph node involvement was present in fifteen patients. The sensitive to detect metastatic nodes was 38% (5/13) for early T1-201 images, 15% (2/13) for delayed T1-201 images, 58% (7/12) for Tc-99m MIBI planar images and 67% (4/6) for Tc-99m MIBI SPECT. The sensitive of Tc-99m MIBI planar or SPECT was significantly higher than that of delayed T1-201 images (p<0.05). CONCLUSION: Early T1-201 and Tc-99m MIBI scan are useful noninvasive methods to differentiate malignant form benign mass of breast. Tc-99m MIBI scan was sensitive in detecting axillary lymph node metastasis in patients with brease cancer.

Role of Redistribution and 24 Hour Reinjection Images to assess Myocardial Viability in Patients with Acute Myocardial Infarction / 대한핵의학회잡지

PURPOSE: We evaluated the importance of redistribution and 24 hour reinjection images in Tl-201 SPECT assessment of myocardial viability after acute myocardial infarction (AMI). MATERIALS AND METHODS: We performed dipyridamole stress-4 hour redistribution-24 hour reinjection Tl-201 SPECT in 43 patients with recent AMI (4-16 days). The myocardium was divided into 16 segments and perfusion grade was measured visually with 4 point score from 0 to 3 (absent uptake to normal uptake). A perfusion defect with stress score 2 was considered moderate. A defect was considered severe if the stress score was 0 or l (absent uptake or severe perfusion decrease). Moderate defect on stress image were considered viable and segments with severe defect were considered viable if they showed improvement of 1 score or more on redistribution or reinjection images. We compared the results of viability assess-ment in stress-redistribution and stress-reinjection images. RESULTS: On visual analysis, 344 of 688 segments (50%) had abnormal perfusion. Fifty two (15%) had moderate perfusion defects and 292 (85%) had severe perfusion defects on stress image. Of 292 severe stress defects, 53 were irreversible on redistribution and reversible on reinjection images, and 15 were reversible on redistribution and irreversible on reinjection images. Two hundred twenty four of 292 segments (76.7%) showed concordant results on stress-redistribution and stress-reinjection images. Therefore 24 hour reinjection image changed viability status from necrotic to viable in 53 segments of 292 severe stress defect (18%). However, myocardial viability was underestimated in only 5% (15/292) of severe defects by 24 hour reinjection. CONCLUSION: The 24 hour reinjection imaging is useful in the assessment of rnyocardial viability. It is more sensitive than 4 hour redistribution imaging. However, both redistribution and reinjection images are needed since they complement each other.