腹直肌肿块的CT影像分析及鉴别诊断

CT analysis and different diagnosis of rectus abdominis muscle mass

目的:分析腹直肌肿块的CT表现,探讨CT诊断思路和要点。方法:对55例经病理证实的腹直肌肿块的CT表现进行回顾性分析。全部病例均行64层螺旋CT平扫及增强扫描,由2位放射科医师结合症状和病史,共同分析肿块的CT影像特征。结果:1韧带样瘤13例:以青年女性多见(11/13),7例有剖宫产史,4例为肿瘤术后复发。大部分病灶(10/13)呈梭形与腹直肌长轴平行,平扫呈等或稍低密度,增强呈明显强化。2血管瘤2例:病灶密度不匀,增强呈延迟强化,可见钙化及血管影各1例。3子宫内膜异位7例:均有剖宫产史。病灶为实性4例,囊实性3例,其中1例可见病灶内出血;增强后肿块实性部分强化较明显。4局灶性肌炎1例。病灶边界不清,密度不均,增强呈不规则强化。5脓肿9例:7例为非特异性脓肿(其中3例为切口感染),2例为特异性脓肿(结核性脓肿)。平扫显示病灶边界不清,有中心坏死区和/或气体影,增强后呈环形或不规则强化。6血肿3例:均有腹部创伤史。病灶呈梭形,边界光整,平扫呈高密度1例、等低混杂密度2例,增强后无强化,1例边缘见新生血管影。7转移瘤20例:均有恶性肿瘤病史。16例手术后患者中合并多处转移12例,其中4例为腹直肌切口转移;4例未行手术者除腹直肌转移外合并多处转移。病灶密度欠均匀、可见不规则坏死灶18例,增强扫描呈环形强化。结论:腹直肌肿块的类型多样,结合临床症状及病史,并对CT表现进行细致观察和分析,能较准确地进行定性诊断。

Objective：To explore key points of diagnosis and clinical relevance for rectus abdominis mass according to the CT appearance. Methods： 55 cases with rectus abdominis muscle mass pathologically proven and received 64-slice CT scan （non-enhanced and contrast enhanced scan） were enrolled. CT findings were reviewed by two radiologists combined with the symptoms and medical history. Results：The clinical and CT features of all cases were as follows：①there was des- moid tumor in 13 cases. The tumors were more common in young female （11/13）. There were 7 cases with a history of ce- sarean section and 4 cases of tumor recurrence. CT scan revealed a hypodense mass in the rectus muscle with intensive en- hancement on enhanced CT images. Most cases （10/13） had a spindle form and parallel to long axis of the rectus ahdominis. ②There were 2 cases with hemangioma. CT showed an isodense mass in the rectus muscle and delayed enhancement on en- hanced CT scan,and calcification and vessels in mass were found in one case. ③ Endometriosis was confirmed in 7 cases,all of them with a history of cesarean section. CT showed abdominal wall mass at incision site. There were solid mass （n=4） and cystic-solid mass （n= 3）. Bleeding in the lesions was noted in one case, the solid portions of the lesions showed relative- ly intensive enhancement on contrast enhanced CT scan. ④There was only one case of focal myositis. CT showed a mass with uneven density and ill-defined border with enhancement on enhanced CT. ⑤There were 9 cases with nonspecific ab- scess （n=7） or tuberculous abscess （n=2） ,3 of them with the incision infection history. CT showed the masses had ill-de- fined border and necrosis area and/or gas inside. Circular or irregular enhancement was noted. ⑥There were 3 cases with hematoma,all had abdominal trauma history. CT scan showed the masses with higher or lower mixed density, without en- hancement on enhanced CT images. The neovascularization in mass was found in 1 case. ⑦There were 20 cases with metas- tases,all patients had the malignancy history. Multiple metastases were found in 12 of 16 postoperative cases. The incision metastases of abdominal wall were found in 4 cases. The other 4 cases without surgery history had multiple metastases be- side retus muscle metatasis. CT showed uneven density and irregular necrosis region with circular enhancement on enhanced CT images in 18 cases. Conclusion：The types of rectus abdominis muscle mass are varied. Combined with clincial history and symptoms,we can make an accurate diagnosis according to CT appereance.