Quantitative assessment of myocardial viability following coronary artery bypass grafting using exercise thallium-201 myocardial single photon emission computed tomography and left ventricular regional wall motion

Using exercise thallium-201 myocardial single photon emission computed tomography (SPECT) and % radial shortening (%RS), 58 patients were evaluated before and after coronary artery bypass grafting (CABG) to quantitatively assess myocardial viability and the effect of CABG. The patient was classified, according to redistribution pattern, as group I with only complete redistribution (20 cases) and group II with including incomplete redistribution (22 cases) and group III with no redistribution (16 cases). 1. Group I was expected complete improvement of ischemic myocardium after CABG but regional left ventricular wall motion was unchanged (sigma i%RS: 142.5 +/- 54.7----138.4 +/- 39.6, sigma a%RS: 201.2 +/- 51.1----238.2 +/- 68.2). 2. Group II was expected to diminish ischemic size after CABG and left ventricular regional wall motion was significantly improved (sigma i%RS: 68.8 +/- 25.9----154.9 +/- 42.6 p less than 0.01, sigma a%RS: 108.4 +/- 62.3----178.9 +/- 77.6, p less than 0.05). 3. Group III was no significant change of ischemic size and left ventricular wall motion after CABG (sigma i%RS: 67.8 +/- 24.1----83.9 +/- 19.2, sigma a%RS: 86.0 +/- 29.0----94.0 +/- 33.9). The present study suggests that quantitative assessment of myocardial viability using exercise thallium-201 myocardial SPECT and %radial shortening was useful method to determine the indication and to assess the effect of CABG.     

Experimental evaluation of retrograde cerebral perfusion by single photon emission computed tomography technique (SPECT).

BACKGROUND: Protection of the brain is of vital importance during aortic arch aneurysms. In this study efficiency of retrograde cerebral perfusion was evaluated with the use of single photon emission computed tomography technique (SPECT) by using 99mTc hexamethylpropylene amine oxime (HMPAO). METHODS: Four animals were used. The internal maxillary vein was the site of retrograde cerebral perfusion. The animals were studied after the heart rate and respiration were stopped with the use of the high dose drug administration and the brain was perfused with cold Ringer's lactated solution. After this procedure, 99mTc HMPAO-SPECT study was performed. RESULTS: In one animal we did not get any cerebral image because of the competent venous valve in the internal maxillary vein. In the remaining animals, normal brain perfusion was achieved. CONCLUSIONS: 99mTc HMPAO-SPECT study documented that blood flow via the retrograde way meets the metabolic demand of the brain. Retrograde delivery of 99mTc HMPAO did not conclude any poorly perfused area in the brain when in given both sides and all parts of the brain can be effectively perfused by cerebral venous system in hypothermic conditions.     

Functional and perfusional assessment with electrocardiograph-gated single photon emission computed tomography after minimally invasive direct coronary artery bypass grafting.

BACKGROUND: Because of limited surgical field, minimally invasive coronary artery bypass grafting (MIDCAB) requires anastomosis to the distal portion of the left anterior descending artery (LAD) of the left internal thoracic artery (LITA) with the heart beating. Though the diameters of these arteries are very small, it is unknown whether blood flow sufficient for the LAD territory is obtained by bypass grafting. METHOD: Eight patients with single-vessel disease of the LAD underwent MIDCAB with the LITA to the LAD and we evaluate the perfusion and function in the LAD territory by quantitative ECG-gated SPECT (QGS) with 99m-technetium sestamibi (MIBI) before and after operation. RESULT: The intraoperatively measured diameters of the LITA and LAD at the site of anastomosis were 1.1+/-0.2 mm and 1.3+/-0.4 mm, respectively. The percentage increases in end-diastolic perfusion, regional ejection fraction and regional wall thickening in the anteroseptal area after MIDCAB were 136.3+/-11.7(p=0.071), 148.4+/-6.6(p=0.007) and 133.0+/-5.6(p=0.029), respectively (paired t-test, mean +/- SD %). Stress-rest MIBI SPECT indicated no ischemia in anteroseptal wall. CONCLUSION: The MIDCAB technique thus appeared to improve perfusion and function in the LAD territory despite bypass to the distal LAD, and ECG-gated MIBI SPECT using QGS software was very useful for evaluating the quality of anastomosis after MIDCAB.     

Acetazolamide enhanced single photon emission computed tomography (SPECT) evaluation of cerebral perfusion before and after carotid endarterectomy.

Twenty-five patients were tested before and after carotid endarterectomy with resting and acetazolamide enhanced single photon emission computed tomography (SPECT) scans with hexamethyl propyleneamine oxine (HMPAO) or iofetamine hydrochloride I123 (123I labeled IMP), both widely available radiopharmaceuticals. Twenty preoperative SPECT studies were asymmetric, revealing focal or diffuse decreased perfusion reserve, and 13 also demonstrated infarcts. Five patients had symmetric (normal) studies. After carotid endarterectomy, 22 cases had changed flow distribution patterns. Usually improvement of reactivity ipsilateral occurred to the area operated on. In four, contralateral improvement was also found. Three of the patients who had preoperative symmetrical scans had increased ipsilateral reactivity after surgery indicating previous global loss of reactivity. Acetazolamide SPECT scans demonstrate a decreased perfusion reserve in 20 patients with carotid artery stenosis, indicating reduced perfusion and poor collateral circulation. Postoperative studies confirm improvement by demonstrating recovery of vascular reactivity in 84% of the patients. Acetazolamide enhanced SPECT scans may be helpful in providing objective evidence for selection of patients for carotid endarterectomy, especially in those who have an 80% carotid artery stenosis, but are asymptomatic.     

Prognostic significance of elevated creatine kinase MB after coronary bypass surgery and after an acute coronary syndrome: results from the GUARDIAN trial

OBJECTIVE: To determine if the correlation between magnitude of creatine kinase-myocardial band release after coronary artery bypass surgery and 6-month mortality is comparable to that of patients admitted with an acute coronary syndrome. METHODS: The GUARDIAN trial tested the efficacy of cariporide, an Na+/H+ exchange inhibitor, on reduction of myocardial ischemia or death in high-risk patients. We compared 6-month survival in a cohort of 2332 GUARDIAN patients scheduled for coronary artery bypass surgery at entry with 4233 acute coronary syndrome patients stratified by level of creatine kinase-myocardial band release. Cumulative 6-month survival by creatine kinase-myocardial band categories was performed using life table analysis, adjusting for variables known to impact prognosis using Cox regression. RESULTS: The 6-month mortality rates for coronary artery bypass surgery patients with peak creatine kinase-myocardial band ratios of <1, > or =1 and <5, > or =5 and <10, and > or =10 upper limits of normal (ULN) were 5.8, 2.8, 5.9, and 12.0%, respectively (P <.0001). The 6-month mortality rates for acute coronary syndrome patients with peak creatine kinase-myocardial band ratios of <1, > or =1 and <5, > or =5 and <10, and > or =10 ULN were 6.3, 9.8, 10.0, and 12.3%, respectively (P <.0001). Patients with coronary artery bypass surgery or acute coronary syndrome had similar adjusted 6-month survival estimates at normal creatine kinase-myocardial band levels and when the creatine kinase-myocardial band level was > or =10 ULN. Patients with coronary artery bypass surgery had significantly better survival at intermediate enzyme levels (> or =1 and <10 ULN; P <.001). CONCLUSIONS: Modest elevations of creatine kinase-myocardial band release (> or =1 and <10 ULN) after coronary artery bypass surgery are not associated with adverse 6-month survival, in contrast to that seen in acute coronary syndrome patients. Routine creatine kinase-myocardial band sampling should be considered in all higher-risk patients undergoing coronary artery bypass surgery procedures to identify the sizable cohort of patients with creatine kinase-myocardial band release > or =10 ULN; these patients may benefit from postoperative angiotensin-converting enzyme inhibitor and beta-blocker therapy. Newer cardioprotective agents that reduce the number of patients with marked creatine kinase-myocardial band release are currently being tested in large randomized controlled clinical trials.     

Hemodynamic evaluation of vascular reconstructive surgery for childhood moyamoya disease using single photon emission computed tomography.

To evaluate the efficacy of vascular reconstructive surgery for childhood moyamoya disease, the cerebral blood flow (CBF) in 31 hemispheres of 16 patients was examined by single photon emission computed tomography (SPECT) using the 133Xe inhalation method. Results were divided into two groups; 17 hemispheres with superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis [A(+) group] and 14 hemispheres without anastomosis [A(-) group]. The mean hemispheric CBF (mCBF) and regional CBF (rCBF) in the frontal, temporal, occipital, and basal ganglia regions were calculated. Pre- and postoperative SPECT on the 10 hemispheres of the A(+) group showed an increase in mCBF in 6 hemispheres, the disappearance of the low perfusion area (LPA) in all 5 hemispheres where LPA was present before surgery, and an improvement in rCBF distribution (an increase in rCBF in the frontal and temporal lobes and a decrease in the basal ganglia). This suggests that vascular reconstruction is greatly effective in treating this disease. A comparison between the A(+) group and the A(-) group by postoperative SPECT, as well as the clinical outcomes and the postoperative findings of electroencephalography and angiography, revealed that the A(+) group was superior to the A(-) group in the frequency of LPA (12% and 43%, respectively) and rCBF in the frontal region where STA-MCA anastomosis was usually performed. These results indicate that STA-MCA anastomosis with indirect synangiosis is the most effective treatment of childhood moyamoya disease.     

Validation of ictal single photon emission computed tomography with depth encephalography and epilepsy surgery

Many centers have reported that ictal single photon emission computed tomography (SPECT) localizes regions of seizure onset with greater sensitivity and specificity than interictal SPECT. Here we report interictal and ictal SPECT scan results in both lesional and nonlesional cases. Using technetium hexamethyl propylamenamine oxide (HMPAO) or ethyl cysteinate dimer (ECD), these scans were done in 52 patients with partial and secondarily generalized seizures. Twenty-five had normal MRI and 27 showed structural lesions. None had mesial temporal sclerosis clearly identified on MRI. All 52 subsequently had interictal and ictal intracranial EEG studies that appeared to localize the seizure focus. Thirty-nine patients had surgery and have been followed for 2 or more years. Interictal SPECT scans showed focal hypoperfusion consistent with intracranial EEG localization of the seizure focus in 29% of patients. In another 13%, there was correct lateralization but not localization. Ictal SPECT scans showed focal hyperperfusion consistent with intracranial EEG localization of the seizure focus in 52% of patients. In another 25%, there was correct lateralization but not localization. The presence or absence of structural lesions on MRI did not affect ictal hyperperfusion or its correlation with intracranial EEG. Thirty-nine patients had resective surgery, of whom 62% had class I outcomes. There was a trend towards better outcome when ictal SPECT data were concordant with intracranial EEG data. The presence or absence of structural lesions on MRI did not affect the likelihood of class I outcome. Ictal SPECT is superior to interictal SPECT in localizing and lateralizing seizure foci. Its results correlate well with intracranial EEG, but in more than one third of cases, the latter shows focal seizure onset in areas that do not show focal hyperperfusion. Surgical outcome tends to be better when the two modalities give concordant results.     

Asymptomatic severe carotid stenosis undergoing staged carotid artery stent and coronary artery bypass grafting: decisive role of brain single photon emission computed tomography

Effort angina of a 70-year-old man was diagnosed as due to triple coronary vessel disease, and he was scheduled to undergo coronary artery bypass surgery. Preoperative carotid duplex scan revealed more than 75% stenosis of the right internal carotid artery, which was functionally proven to be significantly ischemic on brain single photon emission computed tomography. Although he was neurologically asymptomatic, we chose staged surgery for fear of stroke during coronary artery bypass surgery. He had successful carotid artery stenting first by neurosurgeons; then, 2 months later he underwent uneventful coronary artery bypass surgery. This experience prompted us to report the case.     

应用单光子发射型计算机断层显像评价剩余肝功能的动物实验研究

目的评价肝功能显像结合单光子发射型计算机断层显像（SPECT）技术对术后肝功能的预测价值。方法20只新西兰白兔,随机平均分为肝纤维化肝癌组和正常组。两组均行肝脏右外叶切除术,术前1d行^99mTc-二乙基乙酰苯胺亚氨二醋酸（^99mTc—EHIDA）肝脏显像,计算代表整体肝功能的5min心区清除指数（HCI5）、5min心肝相关指数（HLI5）、15min肝脏排泄率（Ex15）,结合SPECT技术计算代表剩余肝功能的HCI5P。Hx15P,和Ex15P;术后4d重复^99mTc—EHIDA肝脏显像。术前1d和术后4d检测肝功能,包括丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）、γ-谷氨酰转肽酶（GGT）、总胆红素（TBil）、总蛋白（TP）、白蛋白（ALB）、胆碱脂酶（CHE）和白蛋白与球蛋白比值（A／G）。结果整体肝功能指标中,肝纤维化肝癌组Ex15低于正常组（P〈0．05）,肝纤维化肝癌组HCI5和HLI5较正常组有升高趋势（P〉0．05）;Ex15,与ALB成正相关、与TBil和GGT成负相关（P〈0．05）,HCI5与CHE成正相关（P〈0．05）,HLI5与A／G成负相关（P〈0．05）。剩余肝功能指标中,HLI5P与术后A／G成负相关（P〈0．05）,Ex15P与TBil和GGT成负相关（P〈0．05）。结论应用肝脏显像结合SPECT技术可以在动物模型上建立三维立体肝功能评估方法,在获得的参数中,Ex15可以定量评价整体肝功能,Ex15P和HLI5P可以预测术后剩余肝功能。