Myocardial Coverage and Radiation Dose in Dynamic Myocardial Perfusion Imaging Using Third-Generation Dual-Source CT.
- 作者列表："Takafuji M","Kitagawa K","Ishida M","Goto Y","Nakamura S","Nagasawa N","Sakuma H
OBJECTIVE:Third-generation dual-source computed tomography (3rd-DSCT) allows dynamic myocardial CT perfusion imaging (dynamic CTP) with a 10.5-cm z-axis coverage. Although the increased radiation exposure associated with the 50% wider scan range compared to second-generation DSCT (2nd-DSCT) may be suppressed by using a tube voltage of 70 kV, it remains unclear whether image quality and the ability to quantify myocardial blood flow (MBF) can be maintained under these conditions. This study aimed to compare the image quality, estimated MBF, and radiation dose of dynamic CTP between 2nd-DSCT and 3rd-DSCT and to evaluate whether a 10.5-cm coverage is suitable for dynamic CTP. MATERIALS AND METHODS:We retrospectively analyzed 107 patients who underwent dynamic CTP using 2nd-DSCT at 80 kV (n = 54) or 3rd-DSCT at 70 kV (n = 53). Image quality, estimated MBF, radiation dose, and coverage of left ventricular (LV) myocardium were compared. RESULTS:No significant differences were observed between 3rd-DSCT and 2nd-DSCT in contrast-to-noise ratio (37.4 ± 11.4 vs. 35.5 ± 11.2, p = 0.396). Effective radiation dose was lower with 3rd-DSCT (3.97 ± 0.92 mSv with a conversion factor of 0.017 mSv/mGy·cm) compared to 2nd-DSCT (5.49 ± 1.36 mSv, p < 0.001). Incomplete coverage was more frequent with 2nd-DSCT than with 3rd-DSCT (1.9% [1/53] vs. 56% [30/54], p < 0.001). In propensity score-matched cohorts, MBF was comparable between 3rd-DSCT and 2nd-DSCT in non-ischemic (146.2 ± 26.5 vs. 157.5 ± 34.9 mL/min/100 g, p = 0.137) as well as ischemic myocardium (92.7 ± 21.1 vs. 90.9 ± 29.7 mL/min/100 g, p = 0.876). CONCLUSION:The radiation increase inherent to the widened z-axis coverage in 3rd-DSCT can be balanced by using a tube voltage of 70 kV without compromising image quality or MBF quantification. In dynamic CTP, a z-axis coverage of 10.5 cm is sufficient to achieve complete coverage of the LV myocardium in most patients.
目的: 第三代双源计算机断层扫描 (3rd-DSCT) 允许10.5 cm z轴覆盖的动态心肌CT灌注成像 (dynamic CTP)。尽管与第二代DSCT (2nd-DSCT) 相比，与50% 更宽的扫描范围相关的增加的辐射暴露可以通过使用70 kv的管电压来抑制，但仍不清楚在这些条件下是否可以维持图像质量和量化心肌血流 (MBF) 的能力。本研究旨在比较2nd-DSCT和3rd-DSCT之间动态CTP的图像质量、估计的MBF和辐射剂量，并评估10.5 cm覆盖是否适合动态CTP。 材料和方法: 我们回顾性分析了107例接受动态CTP的患者，这些患者使用80 kv的2nd-DSCT (n = 54) 或70 kv的3rd-DSCT (n = 53)。比较图像质量、估计MBF、辐射剂量和左心室 (LV) 心肌覆盖。 结果: 在对比噪声比方面，3rd-DSCT和2nd-DSCT之间没有观察到显著差异 (37.4 ± 11.4对35.5 ± 11.2，p = 0.396)。3rd-DSCT的有效辐射剂量 (3.97 ± 0.92 mSv，转换因子为0.017 mSv/mGy·cm) 低于2nd-DSCT (5.49 ± 1.36 mSv，p <0.001)。2nd-DSCT不完全覆盖比3rd-DSCT更常见 (1.9% [1/53] 比56% [30/54]，p <0.001)。在倾向评分匹配的队列中，非缺血性患者3rd-DSCT和2nd-DSCT之间的MBF相当 (146.2 ± 26.5 vs. 157.5 ± 34.9 ml/min/100g，p = 0.137) 以及缺血心肌 (92.7 ± 21.1 vs. 90.9 ± 29.7 ml/min/100g，p = 0.876)。 结论: 通过使用70 kv的管电压可以平衡3rd-DSCT中加宽的z轴覆盖固有的辐射增加，而不会损害图像质量或MBF定量。在动态CTP中，10.5厘米的z轴覆盖足以在大多数患者中实现LV心肌的完全覆盖。
METHODS::We present the case of a 61-year-old woman with a large tumoral infiltration extending from the pelvis throughout the inferior vena cava inferior to the right atrium, protruding into the right ventricle and right ventricular outflow tract. She had been treated 10 years before for low-grade endometrial stromal sarcoma by hysterectomy and adnexectomy followed by hormone- and radio-therapy. Due to cancer recurrence, she underwent peritonectomy, appendectomy, and resection of terminal ileum.
METHODS:AIMS:Significant platelet activation after long stented coronary segments has been associated with periprocedural microvascular impairment and myonecrosis. In long lesions treated either with an everolimus-eluting bioresorbable vascular scaffold (BVS) or an everolimus-eluting stent (EES), we aimed to investigate (a) procedure-related microvascular impairment, and (b) the relationship of platelet activation with microvascular function and related myonecrosis. METHODS AND RESULTS:Patients (n=66) undergoing elective percutaneous coronary intervention (PCI) in long lesions were randomised 1:1 to either BVS or EES. The primary endpoint was the difference between groups in changes of pressure-derived corrected index of microvascular resistance (cIMR) after PCI. Periprocedural myonecrosis was assessed by high-sensitivity cardiac troponin T (hs-cTnT), platelet reactivity by high-sensitivity adenosine diphosphate (hs-ADP)-induced platelet reactivity with the Multiplate Analyzer. Post-dilatation was more frequent in the BVS group, with consequent longer procedure time. A significant difference was observed between the two groups in the primary endpoint of ΔcIMR (p=0.04). hs-ADP was not different between the groups at different time points. hs-cTnT significantly increased after PCI, without difference between the groups. CONCLUSIONS:In long lesions, BVS implantation is associated with significant acute reduction in IMR as compared with EES, with no significant interaction with platelet reactivity or periprocedural myonecrosis.
METHODS:BACKGROUND:Aortopulmonary window is an uncommon congenital heart disease, with untreated cases not surviving beyond childhood. However, very rarely it can present in adult patients with features of pulmonary hypertension. Clinically these patients cannot be differentiated from other more common conditions with left to right shunt. Transthoracic echocardiography if performed meticulously, can depict the defect in aortopulmonary septum. RESULTS:We report a case of large unrepaired aortopulmonary window in a 23 years old patient, diagnosed on transthoracic echocardiography.