Magota Keiichi, Hattori Naoya, Manabe Osamu, Naya Masanao, Oyama-Manabe Noriko, Shiga Tohru, Kuge Yuji, Yamada Shiro, Sakakibara Mamoru, Yoshinaga Keiichiro, Tamaki Nagara
Department of Radiology, Hokkaido University Hospital, Kita 14 Nishi 5, Kita-ku, Sapporo, Hokkaido, 060-8648, Japan.
Ann Nucl Med. 2014 Apr;28(3):187-95. doi: 10.1007/s12149-013-0795-4. Epub 2013 Dec 10.
Application of the electrocardiographically (ECG) gated positron emission tomography (PET) technique with (11)C-hydroxyephedrine (HED) would allow the simultaneous assessment of cardiac sympathetic and contractile functions. However, there are uncertainties regarding the diagnostic accuracy of left ventricular (LV) volume measurements using ECG-gated HED-PET. The purpose of this study was to clarify the minimal requirement of count statistics to measure LV volumes with ECG-gated HED-PET and to investigate the reliability of the measurements.
Five healthy volunteers and 11 patients with heart failure underwent a 40-min list-mode PET scan after an injection of HED (197 ± 35 MBq). The list-mode data were histogrammed into multiple sets of acquisition periods at 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 12.0 Mcount/bin and reconstructed into corresponding gated images using an iterative algorithm. The LV end-diastolic volume (LVEDV), the LV end-systolic volume (LVESV), and the LV ejection fraction (LVEF) were calculated in each acquisition period. These values were compared with those obtained by cardiac magnetic resonance imaging (MRI). Possible effects of HED retention on the accuracy of the volume measurements were investigated.
Collecting less than 4.0 Mcount/bin resulted in noisy cardiac images. The lower counts resulted in underestimation in the volume measurements. Reasonably accurate volume measurements required equal to or greater than 6.0 Mcount/bin. This corresponded to 7.0 ± 1.9 min (range, 4.0-10.3 min) for the acquisition period. Volumetric results using the 6.0 Mcount/bin data highly correlated with cardiac MRI (LVEDV: r = 0.85, p < 0.0001; LVESV: r = 0.89, p < 0.0001; LVEF: r = 0.77, p < 0.01). The HED retention did not affect the volumetric results compared to the MRI volumetry.
The volumetric accuracy with ECG-gated HED-PET was affected by the count statistics rather than the HED retention. LV volume measurements were feasible with 10-min acquisition period for most of the patients. This technique allows the simultaneous assessment of cardiac sympathetic and contractile functions without the need for an additional injection or scanning time, thus reducing overall costs for diagnostic imaging.
应用心电图（ECG）门控正电子发射断层扫描（PET）技术结合（11）C - 羟基麻黄碱（HED）可同时评估心脏交感神经和收缩功能。然而，使用ECG门控HED - PET测量左心室（LV）容积的诊断准确性存在不确定性。本研究的目的是明确使用ECG门控HED - PET测量LV容积时计数统计的最低要求，并研究测量的可靠性。
5名健康志愿者和11名心力衰竭患者在注射HED（197±35 MBq）后接受了40分钟的列表模式PET扫描。列表模式数据被直方图化为多组采集时间段，采集时间段分别为0.5、1.0、2.0、4.0、6.0、8.0、12.0兆计数/箱，并使用迭代算法重建为相应的门控图像。在每个采集时间段计算LV舒张末期容积（LVEDV）、LV收缩末期容积（LVESV）和LV射血分数（LVEF）。将这些值与通过心脏磁共振成像（MRI）获得的值进行比较。研究了HED滞留对容积测量准确性的可能影响。
采集少于4.0兆计数/箱会导致心脏图像出现噪声。计数较低会导致容积测量值被低估。合理准确的容积测量需要等于或大于6.0兆计数/箱。这对应于采集时间段为7.0±1.9分钟（范围为4.0 - 10.3分钟）。使用6.0兆计数/箱数据的容积测量结果与心脏MRI高度相关（LVEDV：r = 0.85，p < 0.0001；LVESV：r = 0.89，p < 0.0001；LVEF：r = 0.77，p < 0.01）。与MRI容积测量相比，HED滞留不影响容积测量结果。
ECG门控HED - PET的容积准确性受计数统计影响，而非HED滞留。对于大多数患者，10分钟的采集时间段即可实现LV容积测量。该技术无需额外注射或扫描时间即可同时评估心脏交感神经和收缩功能，从而降低了诊断成像的总体成本。
