The Quantitative Effect of Attenuation Correction on ECG-gating Myocardial Perfusion Scintigraphy

衰減校正在柵式心肌血流造影的定量效果

胡晉(Chin Hu) ； 邱宇莉(Yu-Li Chiu) ； 馬光遠(Guang-Yuan Mar) ； 林雯君(Wen-Chun Lin) ； 吳家尚(Chia-Shang Wu) ； 彭南靖(Nan-Jing Peng)

《核子醫學暨分子影像雜誌》 25卷1期 (2012/03) Pp. 15-20+ii

摘要

Objectives: Myocardial perfusion scintigraphy (MPS) is a valuable tool for the detection and localization of coronary artery disease (CAD). Its diagnostic accuracy is limited by irregular body photon attenuation. The aim of this study is to compare attenuation correction (AC) with non-AC (NC) on the distribution of myocardial perfusion, and to evaluate the quantitative effect of using AC on MPS for the assessment of CAD. Methods: Thirty-nine patients undergoing dual-isotope ECG-gating MPS were included. Resting imaging was performed 5 min after administration of 74 MBq TI-201. Persantin-induced stress study was performed 30 min after injection of 1110 MBq Tc-99m MIBI. All images were acquired with a dual-head gamma camera (Siemens ECAM), equipped with two scanning Gd-153 line sources. Images were reconstructed using iterative maximum-likelihood algorithm with and without AC. The perfusion percentage from the five individual walls of anterior wall, septum, inferior wall, lateral wall and apex, defect extent and defect severity were calculated, respectively. The myocardial perfusion between AC and NC studies was analyzed by using a paired t test. The significance level was set at P ＜ 0.05. Results: Twenty of the 39 patients were proven of no evidence of CAD or restenosis (Group 1), while the rest 19 patients were documented of CAD (Group 2). Among the five individual walls in Group 1 patients, the perfusion percentage was changed greatest in the inferior wall after AC, which increased 13.0 + 5.2% on rest TI-201 and 13.6 + 5.8% on stress Tc-99m MIBI images, respectively (P ＜ 0.001). In Group 2 patients, the defect extent changed from 19.6 + 13.2% to 14.9 + 12.1% (P＜0.01) on rest TI-201 and 23.2 + 13.6% to 20.7 + 11.5% on stress Tc-99m MIBI images (p=0.055) after AC. The defect severity of the myocardium changed from 15.6 + 10% to 7.6 + 8.1% (P ＜ 0.001) on rest TI-201 and 18.4 + 10.5% to 15.6 + 7.6% (P ＜ 0.05) on stress Tc-99m MIBI images after AC. Conclusion: AC significantly corrects the myocardial perfusion for patients without CAD, thereby reducing the possibility of false-positive results. AC could also change the defect extent and defect severity for patients with CAD, and help to precisely clarify the area of myocardial abnormality.

關鍵字

attenuation correction ； myocardial perfusion scintigraphy ； SPECT ； Tc-99m MIBI ； TI-201

並列摘要

背景：心肌血流造影為偵測及定位冠心病的重要工具，其正確性卻受限於身體造成的光子衰減現象，本研究目的在透過柵式心肌血流造影來比較衰減校正對於心肌血流分布之差異，探討衰減校正對於評估冠心病的定量效果。方法：39位病患接受雙同位素柵式心肌血流造影，注射74百萬貝克的鉈-201 5分鐘後進行休息態造影，注射1100百萬貝克的鎝-99m MIBI 30分鐘後進行由保心丁藥理刺激的壓力態造影。以Siemens E.CAM雙頭造影機收集影像，釓-153線射源進行衰減校正。透過反覆式最大可能重建的數學模式，配合衰減校正之有無使用來重組影像。左心室分為前壁、心中膈、下壁、側壁及心尖，以配對t test來比較衰減校正在心肌血流百分比，缺損範圍與嚴重度的差異性，P ＜ 0.05為顯著差異。結果：20位病患無冠心病或無血管再狭窄（群組1），19位病患有冠心病（群組2）。衰減校正改變群組1病患的心肌血流分布，五個心室壁中以下壁改變最多（P ＜ 0.001），休息態鉈-201造影增加13.1±5.2％、壓力態鎝-99m MIBI造影增加13.6±5.8％。群組2病患的缺損範圍休息態鉈-201造影由19.62±13.2％減至14.9±12.1％（P ＜ 0.01）、壓力態鎝-99m MIBI造影由23.2±13.6％減至20.7±1 1.5％（P = 0.055）。缺損嚴重度休息態鉈-201造影由15.6±10％減至7.6±8.1％（P ＜ 0.001）、壓力態鎝-99m MIBI造影由18.4±10.5％減至15.6±7.6％（P ＜ 0.05）。結論：衰減校正明顯地校正心臟各區心肌血流、減少偽陽性的發生，也改變了冠心病者的心肌缺損範圍及嚴重度，準確辨識出心肌異常區。

並列關鍵字

衰減校正 ； 心肌血流造影 ； 單光子電腦斷層掃描 ； 鉈-201 ； 鎝-99m MIBI