背景:心肌脓肿通常与感染性心内膜炎(IE)有关,无IE的孤立性心肌脓肿少见。超声心动图和计算机断层扫描(CT)通常用于诊断心肌脓肿;然而,据我们所知,尚未使用背景人体信号抑制(DWIBS)的扩散加权全身磁共振成像。这里,我们介绍一例使用DWIBS诊断为无IE的心肌脓肿。
方法:一位72岁有高血压病史的日本男性,血脂异常,和色素性视网膜炎因不适和发烧持续10天出现在我们医院。血液检查结果显示炎症标志物水平升高(白细胞计数18,700/µL和C反应蛋白水平23.0mg/dL)。怀疑感染;然而,无法确定感染源。DWIBS,在入院的第7天进行,以确定感染源,右墙周围有一个高信号,提示炎症。在住院的第1天进行的对比增强CT显示同一区域的低密度区域;但是,这一发现的病理意义无法确定.根据DWIBS的调查结果,我们得出的结论是,这种情况表现为心肌脓肿,特别局限于右心房壁。三组血培养显示阴性结果,超声心动图显示无植被或瓣膜返流。因此,患者被诊断为孤立性心肌脓肿,未并发IE。入院时的心电图显示无P波,病人有交界性节律.然而,在住院的第20天,他出现了完全房室传导阻滞.抗生素治疗后心肌脓肿完全愈合后得到证实,患者接受了起搏器植入术.手术后十个月,患者没有感染复发的迹象。
结论:仅根据病史和体格检查,孤立性心肌脓肿的诊断具有挑战性.除了CT和超声心动图,DWIBS可能有助于心肌脓肿的诊断。
Myocardial abscess is often associated with infective endocarditis (IE), and isolated myocardial abscess without IE is rare. Echocardiography and computed tomography (CT) are often used to diagnose myocardial abscess; however, to the best of our knowledge, diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression (DWIBS) has not been used. Here, we present a case of myocardial abscess without IE that was diagnosed using DWIBS.
A 72-year-old Japanese man with a history of hypertension, dyslipidemia, and retinitis pigmentosa presented to our hospital with malaise and a fever lasting 10 days. Blood test results showed elevated inflammatory marker levels (white blood cell count 18,700/µL and C-reactive protein level 23.0 mg/dL). Infection was suspected; however, the source of the infection could not be identified. DWIBS, which was performed on day 7 of admission to determine the source of infection, showed a high signal surrounding the right wall, suggesting inflammation. Contrast-enhanced CT performed on day 1 of hospitalization revealed a low-density area in the same region; however, the pathological implications of this finding could not be determined. Based on DWIBS findings, we concluded that the condition presented as a myocardial abscess that was confined specifically to the right atrial wall. Three sets of blood cultures revealed negative findings, and echocardiography showed no vegetation or valve regurgitation. Therefore, the patient was diagnosed with an isolated myocardial abscess uncomplicated with IE. An electrocardiogram on admission showed no P waves, and the patient had a junctional rhythm. However, on day 20 of hospitalization, he developed a complete atrioventricular block. After complete myocardial abscess healing following antibiotic treatment was confirmed, the patient underwent pacemaker implantation. Ten months after surgery, the patient had no signs of infection recurrence.
Based on history and physical examination alone, diagnosis of an isolated myocardial abscess can be challenging. In addition to CT and echocardiography, DWIBS might be helpful for the diagnosis of myocardial abscesses.