Hoefflinghaus Tobias, Husmann Lars, Valenta Ines, Moonen Clemens, Gaemperli Oliver, Schepis Tiziano, Namdar Mehdi, Koepfli Pascal, Siegrist Patrick T, Kaufmann Philipp A
Cardiovascular Center, University Hospital Zurich, Zurich, Switzerland.
Clin Nucl Med. 2008 Nov;33(11):748-51. doi: 10.1097/RLU.0b013e318187ee9c.
To define the impact of attenuation correction (AC) on interpretation of perfusion abnormalities induced by left bundle branch block (LBBB) in myocardial perfusion imaging (MPI) and single photon emission computed tomography (SPECT).
Thirty-six patients with spontaneous and 12 with pacemaker (PM)-induced LBBB (mean age 68.6 +/- 9.7) underwent gated 1-day adenosine stress/rest Tc-99m tetrofosmin SPECT on a hybrid SPECT-CT dual-head detector camera with Hawkeye facility (Infinia, GE Healthcare, Milwaukee, WI). Images were analyzed using iterative reconstruction (IR) and AC by computerized tomography (IR-AC) and compared with filtered back protection (FBP) as a standard of reference. Defect extent and severity for the anterior, septal, apical, inferior, and lateral regions were assessed by computerized analysis. The combination of septal with anterior and/or apical perfusion defects was attributed to the typical LBBB-induced pattern.
LBBB caused a typical perfusion pattern in 24 patients with spontaneous and in 10 with PM-induced LBBB, whereas MPI was normal in 14 patients. FBP revealed a partial reversibility of anterior (spontaneous LBBB) and apical-septal (spontaneous and PM-induced LBBB) defect severity. By IR-AC, LBBB caused comparable anteroseptal reversible perfusion defects (P < 0.05) but fixed apical defects. Apical-septal defect severity was higher and defect extent was larger in IR-AC compared with FBP (both P < 0.05). Defect extent was unchanged between rest and stress for both reconstructions.
Spontaneous and PM-induced LBBB often induces typical perfusion defects in MPI at stress, partly reversible at rest. With IR-AC this typical pattern is more pronounced and less reversible, strengthening the confidence to discriminate such findings from ischemia.
确定衰减校正（AC）对心肌灌注成像（MPI）和单光子发射计算机断层扫描（SPECT）中左束支传导阻滞（LBBB）所致灌注异常解读的影响。
36例自发性和12例起搏器（PM）诱发LBBB患者（平均年龄68.6±9.7岁），在配备鹰眼设备（Infinia，GE医疗，密尔沃基，威斯康星州）的混合型SPECT-CT双头探测器相机上进行门控1日腺苷负荷/静息锝-99m替曲膦SPECT检查。使用迭代重建（IR）和计算机断层扫描衰减校正（IR-AC）分析图像，并与作为参考标准的滤波反投影（FBP）进行比较。通过计算机分析评估前壁、间隔、心尖、下壁和侧壁区域的缺损范围和严重程度。间隔与前壁和/或心尖灌注缺损的组合归因于典型的LBBB诱发模式。
LBBB在24例自发性和10例PM诱发LBBB患者中导致典型灌注模式，而14例患者的MPI正常。FBP显示前壁（自发性LBBB）和心尖间隔（自发性和PM诱发LBBB）缺损严重程度有部分可逆性。通过IR-AC，LBBB导致类似的前间隔可逆性灌注缺损（P<0.05），但心尖缺损固定。与FBP相比，IR-AC中心尖间隔缺损严重程度更高，缺损范围更大（均P<0.05）。两种重建方法在静息和负荷时缺损范围均无变化。
自发性和PM诱发的LBBB在负荷时MPI常诱发典型灌注缺损，静息时部分可逆。使用IR-AC时，这种典型模式更明显且可逆性更低，增强了将此类表现与缺血相鉴别的信心。
