Vehof Volker, Büther Florian, Florian Anca, Drakos Stefanos, Chamling Bishwas, Kies Peter, Stegger Lars, Yilmaz Ali
Department of Cardiology I, University Hospital Münster, Münster, Germany.
Department of Nuclear Medicine, University Hospital Münster, Münster, Germany.
Front Cardiovasc Med. 2022 Jan 31;9:793972. doi: 10.3389/fcvm.2022.793972. eCollection 2022.
Cardiac involvement in patients with Becker muscular dystrophy (BMD) is an important predictor of mortality. The cardiac phenotype of BMD patients is characterized by slowly progressive myocardial fibrosis that starts in the left ventricular (LV) free wall segments and extends into the septal wall during the disease course.
Since the reason for this characteristic cardiac phenotype is unknown and comprehensive approaches using e.g. hybrid imaging combining cardiovascular magnetic resonance (CMR) with F-fluorodeoxyglucose (FDG) positron emission tomography (PET) are limited, the present study addressed this issue by a comprehensive non-invasive imaging approach.
Hybrid CMR- and FDG-PET-imaging was performed in = 14 patients with BMD on a whole-body Biograph mMR system (Siemens, Erlangen, Germany). The CMR protocol comprised cine- and late-gadolinium-enhancement (LGE)-imaging. Metabolism was assessed with FDG-PET after oral glucose loading to effect myocardial carbohydrate uptake. PET was acquired for 65 min starting with tracer injection. Uptake values from 60 to 65 min p.i. were divided by the area under the blood activity curve and reported as percentages relative to the segment with maximal myocardial FDG uptake.
A characteristic pattern of LGE in the LV lateral wall was observed in 13/14 patients whereas an additional septal LGE pattern was documented in 6/14 patients only. There was one patient without any LGE. Segmental FDG uptake was 88 ± 6% in the LV lateral wall vs. 77 ± 10% in the septal wall ( < 0.001). There was an inverse relationship between segmental FDG activity compared to segmental LGE extent ( = -0.33, = 0.089). There were = 6 LGE-positive patients with a segmental difference in FDG uptake of >15% in the LV lateral wall compared to the septal wall = ΔFDG-high group (lateral FDG = 91±3% vs. septal FDG = 69±8%; < 0.001) while the remaining = 7 LGE-positive patients showed a segmental difference in FDG uptake of ≤ 15% = ΔFDG-low group (lateral FDG = 85±7% vs. septal FDG = 83 ± 5%; = 0.37). Patients in the ΔFDG-high group showed only a minor difference in the LGE extent between the LV lateral wall vs. septal wall ( = 0.09) whereas large differences were observed in the ΔFDG-low group ( < 0.004).
Segmental FDG uptake-reflecting myocardial metabolic activity-is higher in the LV free wall of BMD patients-possibly due to a higher segmental work load. However, segmental metabolic activity seems to be dependent on and limited by the respective segmental extent of myocardial fibrosis as depicted by LGE-imaging.
贝克型肌营养不良症（BMD）患者的心脏受累是死亡率的重要预测指标。BMD患者的心脏表型特征为缓慢进展的心肌纤维化，始于左心室（LV）游离壁节段，并在病程中延伸至间隔壁。
由于这种特征性心脏表型的原因尚不清楚，且使用例如将心血管磁共振（CMR）与F-氟脱氧葡萄糖（FDG）正电子发射断层扫描（PET）相结合的混合成像等综合方法有限，本研究通过全面的非侵入性成像方法解决了这一问题。
在一台全身Biograph mMR系统（西门子，埃尔朗根，德国）上对14例BMD患者进行了CMR和FDG-PET混合成像。CMR方案包括电影成像和延迟钆增强（LGE）成像。口服葡萄糖负荷后用FDG-PET评估代谢，以实现心肌碳水化合物摄取。从注射示踪剂开始采集PET 65分钟。注射后60至65分钟的摄取值除以血液活性曲线下的面积，并报告为相对于心肌FDG摄取最大节段的百分比。
13/14例患者在LV侧壁观察到特征性的LGE模式，而仅6/14例患者记录到额外的间隔LGE模式。有1例患者无任何LGE。LV侧壁节段FDG摄取为88±6%，而间隔壁为77±10%（P<0.001）。节段FDG活性与节段LGE范围之间呈负相关（r=-0.33，P=0.089）。有6例LGE阳性患者，LV侧壁与间隔壁的节段FDG摄取差异>15%=ΔFDG高组（侧壁FDG=91±3%，间隔壁FDG=69±8%；P<0.001），而其余7例LGE阳性患者的节段FDG摄取差异≤15%=ΔFDG低组（侧壁FDG=85±7%，间隔壁FDG=83±5%；P=0.37）。ΔFDG高组患者LV侧壁与间隔壁之间的LGE范围仅存在微小差异（P=0.09），而ΔFDG低组观察到较大差异（P<0.004）。
反映心肌代谢活性的节段FDG摄取在BMD患者的LV游离壁中较高，可能是由于节段工作负荷较高。然而，节段代谢活性似乎取决于LGE成像所显示的心肌纤维化的相应节段范围，并受其限制。
