乳腺分叶状肿瘤的X线表现及病理对照分析

目的:分析乳腺分叶状肿瘤的X线表现,以提高对该病的认识。方法:回顾性分析经手术病理证实的16例乳腺分叶状肿瘤的X线表现及临床资料,并与病理结果进行对照。结果:16例乳腺分叶状肿瘤中,良性11例,交界性3例,恶性2例。乳腺X线表现为肿块10例,其中无钙化肿块9例,肿块伴钙化1例;类圆形3例,分叶状7例;边缘清晰4例,边缘模糊6例。乳腺X线表现为边缘模糊的团块状致密腺体影6例。乳腺X线诊断与病理诊断的符合率为62.5%。结论:乳腺分叶状肿瘤在乳腺X线表现上不具特异性,最终仍依靠组织病理学诊断。     

乳腺叶状肿瘤26例数字钼靶X线分析

目的分析乳腺叶状肿瘤的X线表现,探讨钼靶X线摄影对乳腺叶状肿瘤的诊断价值。方法回顾分析我院26例经手术病理证实的乳腺叶状肿瘤患者术前乳腺X线检查资料。结果26例乳腺叶状肿瘤中,良性21例(80.8%)交界性3例(11.5%)恶性2例(7.7%)。其中18例乳腺叶状肿瘤多位于外上象限,直径1.7～9.3cm,19例肿块表现为圆形、边缘光整,5例表现为分叶状,7例为多发肿块,2例为边缘模糊、有毛刺征,1例发现钙化灶,21例发现"透明晕"。结论妇女乳房内肿块大、分叶状且周边有"透明晕"是乳腺叶状肿瘤较特征的X线征象,近期肿块迅速增大有助于叶状肿瘤的诊断。X线表现与组织学分型有一定关系,边缘模糊,有毛刺提示恶性程度较高。认识乳腺叶状肿瘤的病理表现和X线特征,有助于提高术前诊断率。     

乳腺叶状肿瘤的X线表现及病理对照分析

目的 分析乳腺叶状肿瘤(phyllodes tumors of the breast, PTs)的X线特征,并与病理结果相对照.方法 回顾性分析60例经手术病理证实PTs的X线特征及病理表现.良性PTs 5例,交界性PTs 45例,恶性PTs 10例,其中1例含有软骨肉瘤成分,1例含有脂肪肉瘤成分,其余PTs含有纤维肉瘤成分.结果 (1)60例PTs,53例X线片表现为肿块,7例为肿块伴钙化,包括交界性PTs 4例,恶性PTs 3例.46例有"透亮晕征".(2)肿物圆形6例,卵圆形14例,分叶形35例(其中14例表现为深分叶或多结节样堆积或肿块周围伴发结节),不规则形5例.26例肿块边缘清楚光滑,28例边缘模糊,6例边缘呈浸润性改变. 结论良性PTs常为边缘清楚的分叶状肿块,边缘浸润的分叶状肿块常为恶性.     

钼靶X线摄影对乳腺癌的诊断价值与技术探讨

目的 :探讨钼靶X线摄影对乳腺癌的诊断价值。方法 :收集我院2007年12月至2011年12月间经手术或穿刺病理证实的乳腺癌患者156例,分析其乳腺X线摄影表现。结果:X线表现为单纯肿块影116例,微小钙化39例,毛刺征36例,边缘呈分叶状46例,瘤周透亮环及异常血管影34例。男性乳腺癌1例。结论:乳腺钼靶X线摄影能直接观察乳腺肿块的大小、分叶、毛刺征及肿块周围的透亮环与异常增多血管影,必要时采用加压放大摄影,可提高微小钙化的检出率,实现乳癌的早期诊断,是乳腺癌临床诊断的首选方法。     

乳腺叶状囊肉瘤临床钼钯X线与彩超征象分析

目的：结合文献资料分析总结乳腺叶状囊肉瘤的临床特点、钼钯X线与彩色多谱勒超声影像征象。方法：随机搜集临床资料完整的乳腺叶状囊肉瘤7例，每例患者均接受钼钯X线与彩色多谱勒超声检查，所有病例均经手术病理证实。结果：叶状囊肉瘤患者病史多较长，病灶体积一般较大，或在短时期内增长迅速。钼钯X线片上病灶多表现为密度均匀、边缘光滑的分叶状肿块。彩色多谱勒超声检查，病灶以不均匀中低回声为主。结论：叶状囊肉瘤多发于40—50岁，患者有较为独特的临床特点，结合钼钯X线与B型超声征象可以作出诊断。     

乳腺叶状瘤的X线及MRI表现

目的探讨乳腺叶状瘤(PT)X线和MRI的影像学特征,以提高其影像诊断和鉴别诊断水平。方法回顾性分析经手术、病理证实的30例PT患者的临床及影像资料,其中22例行X线检查,19例行MRI。结果 30例均为单发,表现为乳腺内直径1.5～21 cm(平均6.2 cm)的肿块;22例行乳腺X线检查者,病灶表现为圆形(5例)或分叶状(17例)、密度高于邻近腺体的肿块,边界清楚(16例)或部分不清(6例),所有病例均未发现钙化及邻近皮肤增厚、乳头回缩、周围乳腺结构扭曲等恶性征象。行MRI的19例患者,病灶表现为圆形(7例)或分叶状(12例),T1WI上呈等信号(8例)或低信号(11例),信号均匀(12例)或不均匀(7例),出现囊变或分隔(5例)、出血(2例);19例肿瘤T2WI上均为高信号,动态增强后时间-信号强度曲线(TIC)呈平台型16例,轻度流出型3例。30例PT病理诊断:Ⅰ级14例,Ⅱ级10例,Ⅲ级6例。结论 PT的影像学表现有一定的特点,尤其MRI动态增强扫描对诊断有重要价值,但其良恶性的判定仍有赖于组织病理学检查。     

乳腺肿瘤性病变的钼靶X线征象分析

目的 明确乳腺肿瘤性病变的钼靶X线征象,评价钼靶在乳腺肿瘤性病变的诊断及鉴别诊断中的价值.资料与方法 总结分析本院从2008年6月至2010年1月共1330例乳腺疾病钼靶X线摄影中检出并经手术和病理证实为乳腺肿瘤患者176例,其中乳腺良性肿瘤103例,乳腺癌70例,交界性叶状肿瘤3例.常规摄乳腺X线片,怀疑乳腺导管内乳头状瘤者,行溢液乳管造影.结果 (1)乳腺良性肿瘤钼靶X线多表现为圆形、椭圆形肿块,边界清楚,周边有或无透明"晕征",导管内乳头状瘤造影多表现为导管内单个或多个充盈缺损.(2)70例乳腺癌的钼靶X线征象,表现为肿块者56例(80%),砂粒状或簇状微钙化46例(66%),肿块伴微钙化42例(60%),结构扭曲、紊乱5例(7%),局灶性致密影3例(4%),血管影增粗24例(34%).(3)叶状肿瘤的钼靶X线表现为圆形或浅分叶状肿块,密度高而均匀,肿块体积较大.结论 乳腺不同良恶性肿瘤具有较为特征性的X线征象,钼靶X线在乳腺良恶性肿瘤的诊断及鉴别诊断中具有重要意义,结合临床病史,可进一步提高诊断准确率.     

乳腺分叶状肿瘤的X线钼钯及MR表现分析

目的探讨乳腺分叶状肿瘤的X线钼钯及MR表现。方法搜集我院经病理证实的乳腺分叶状肿瘤病人18例,常规行双乳轴位及内外侧斜位钼靶摄片,4例加做MR平扫加增强扫描。分析其X线及MR表现,以提高诊断准确率。结果 18例病人均行钼靶摄影,4例行MR摄影,表现为肿块16例(其中1例为复发),结构紊乱2例(均为复发)。单发肿块12例,多发4例。18例中良性5例,交界性8例,恶性5例。肿块形态呈分叶状11例、圆形3例,类圆形2例。16例中肿块周围有晕环14例,边缘模糊2例,2例伴腋下淋巴结肿大,1例伴沙砾样钙化。1例MR于T2WI高信号内见低信号分隔,增强后其内可见囊变区,为其特征性表现。结论乳腺分叶状肿瘤发病率低,生物学行为复杂,而影像学表现缺乏特异性,分析并认识其影像学特征对术前诊断很重要。     

乳腺肿瘤X线摄影临床价值分析

目的探讨乳腺X线摄影在乳腺肿瘤鉴定与诊断中的应用价值。方法分析70例X线摄影的乳腺肿块患者的影像学资料,X线诊断结果与病理结果进行对比分析。结果乳腺X线摄影结果与金标准病理诊断的符合率为80.00%。70例腺肿块患者的肿块及结构扭曲、钙化等征象23例,仅表现微钙化征象11例,毛刺样肿块21例,伴乳头凹陷8例,乳腺皮肤增厚10例,肿块周围粗大血管征5例。6例良性病变误诊为恶性病变:3例为右乳外上象限肿块影,边缘清晰,呈浅分叶状,未见明显钙化,术后病理结果为乳腺结核;2例为左乳外上象限大片状致密影,其内大片成簇状微小钙化,病理结果为乳腺囊肿;1例为左乳头深部肿块影,边缘模糊欠规整,病理结果为乳腺囊肿。8例良性病变因钼靶表现为边缘模糊,未见明显毛刺征象,术前误诊为乳腺癌。乳腺肿瘤钼靶X线诊断乳腺肿瘤的敏感性、特异性及准确性分别为79.49%、80.65%、80.00%。结论肿块及微小钙化是乳腺癌最直接、最主要的X线征象,乳腺X线摄影对乳腺组织结构显示清晰,特别是对微小钙化有很高的诊断价值。     

乳腺叶状瘤的影像诊断

目的 总结分析乳腺叶状瘤X线钼靶照片和超声检查的影像学特征。方法 搜集1991年1月至2003年5月经手术、病理证实的25例乳腺叶状瘤，其中13例行X线钼靶摄片，17例行超声检查，回顾性分析其临床特点及影像学征象。结果 25例乳腺叶状瘤中病理诊断Ⅰ级者17例，Ⅱ级7例，Ⅲ级1例。13例行乳腺X线钼靶检查患者病灶表现为圆形(7例)或浅分叶状(6例)密度高于邻近腺体的肿块，边界清楚(8例)或部分不清(5例)，所有病例均未发现钙化及邻近皮肤增厚、乳头回缩、周围乳腺结构扭曲等恶性征象。行乳腺超声检查的17例患者，病灶表现为低回声者16例，边界规整者16例，出现囊变者10例，11例出现后方回声增强。结论 乳腺叶状瘤的影像学表现有一定的特点，但这些表现为非特征性，与纤维腺瘤等边界清楚的实性病灶的鉴别有一定的困难，对可疑病灶行切除活检非常必要。     

乳腺叶状肿瘤的MRI表现及临床病理学分析

目的:分析乳腺叶状肿瘤(phyllodes tumors,PTs)的MRI表现,以提高MRI的诊断价值。方法:回顾性分析8例PTs患者的临床及影像资料,包括肿瘤在T1WI、STIR序列上的信号强度,肿瘤大小、形状、边缘、内部强化方式、早期强化率、时间-信号强度曲线(time-signal intensity curve,TIC)类型及ADC值;比较PTs与正常腺体ADC值的差异。结果:8例乳腺PTs中,3例良性,4例交界性,1例恶性。MRI平扫T1WI呈等及较低信号,STIR呈高信号,3例肿瘤内见低信号未强化分隔,6例见裂隙状高信号;最大径线2.4~7.5cm;2例呈圆形、类圆形,6例呈分叶状;8例边缘均较清晰;增强扫描病灶均呈不均匀强化;7例PTs早期强化率大于100%,1例50%且100%;TIC类型1例为流入型,5例为平台型,2例为廓清型。DWI病灶均呈高信号,且ADC值低于正常腺体,PTs平均ADC值为(1.30±0.25)×10-3 mm2/s,正常腺体ADC值为(1.64±0.12)×10-3 mm2/s,二者差异有统计学意义(t=3.375,P0.05)。结论:乳腺PTs的MRI征象具有一定的特征性,结合其临床特点综合分析,可提高其术前诊断准确率。     

Fibrosarcoma of the breast: mammographic findings in five cases.

The mammographic features of fibrosarcoma of the breast, a rare malignant tumor, have not been described. Accordingly, we reviewed the mammograms, pathology reports, and medical records of five women with this tumor. All cases had surgical biopsies and a diagnosis made by histologic evaluation. The age of the patients ranged from 48 to 79 years. Histologically, three of the five fibrosarcomas were thought to have arisen from phyllodes tumor, and four were palpable. On mammograms, the tumors were dense masses with largely indistinct margins, ranging from 1.5 to 7.0 cm in diameter. One contained calcified osseous elements suggesting osseous trabeculae. Although the osseous trabeculae in that tumor strongly suggested sarcoma, most of the tumors had a nonspecific appearance on mammograms. Fibrosarcomas of the breast have a nonspecific mammographic appearance. Surgical biopsy and histologic evaluation are necessary for definitive diagnosis.     

Phyllodes tumor of the breast: correlation between MR findings and histologic grade

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of phyllodes tumor of the breast and to compare these findings with the histologic grade. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The authors reviewed the MR findings in 30 female patients aged 16-73 years (mean, 40.2 years) with surgically confirmed phyllodes tumors. Analyzed MR findings included tumor shape, margin, internal enhancement, and size; signal intensity (SI) of tumor higher than that of normal breast tissue on T1-weighted images; SI of tumor lower than or equal to that of normal tissue on T2-weighted images; cyst wall appearance; kinetic curve assessment; and apparent diffusion coefficient (ADC). The MR findings and histologic grade were statistically analyzed to determine whether any correlations existed. Significant MR findings were compared with histopathologic findings. RESULTS: Nineteen benign, six intermediate (characterized by five to nine cell reproductions at 10 high-power fields, pushing or infiltrative margins, moderate stromal cellularity, and atypia and overgrowth), and five malignant phyllodes tumors were assessed. Irregular cyst wall (P = .003), tumor SI lower than or equal to normal tissue SI on T2-weighted images (P = .005), and low ADC (P = .001) correlated significantly with histologic grade. Tumor SI higher than normal tissue SI on T1-weighted images was more frequent in the malignant (in three of five tumors) and intermediate (in three of six tumors) groups than in the benign group (in two of 19 tumors); however, it was not a significant finding (P = .024). Tumor SI higher than normal tissue SI on T1-weighted images and irregular cyst wall corresponded histopathologically to hemorrhagic infarction and necrosis, respectively. Tumor SI lower than or equal to normal tissue SI on T2-weighted images and low ADC corresponded histopathologically to stromal hypercellularity. Other findings were not significant. CONCLUSION: Several MR findings can be used to help determine the histologic grade of phyllodes breast tumors.     

Phyllodes tumors of the breast

The aim of this study was to describe the clinical, mammographic, and sonographic findings of phyllodes tumor of the breast and correlate them to the benign or malignant pathological nature of the lesion and its clinical behavior. We retrospectively reviewed the clinical, radiologic, and pathologic findings of 12 cases of phyllodes tumors diagnosed in our hospital in the past 6 years, 6 of which were malignant. The surgical management and clinical course of the patients were also reviewed. Mammographically, soft tissue masses ranging from 2.5 to 15 cm were present in all patients. One patient had a mixed fat and water density mass and 2 patients had masses associated with coarse calcifications. At sonography, all tumors were well circumscribed; two of them were homogeneously hypoechoic, and the rest had heterogeneous internal echoes. Eight patients showed internal cystic areas. None of these characteristics proved to be useful in ascertaining the benign or malignant nature of the tumor. At surgery, 5 patients underwent mastectomy and 7 patients local excision of the tumor. Three of the later tumors, one benign and two malignant, recurred after several months. Fine-needle aspiration biopsy suggested the diagnosis of phyllodes tumor in only 3 cases. After surgery, six tumors were classified as benign and six as malignant, three of which being of low-grade malignancy. None of the clinical or radiologic characteristics of the tumors were useful in predicting their histological nature or their behavior after surgery. Preoperative fine-needle aspiration biopsy often misdiagnosed the tumor as benign fibroadenoma. Only the histopathologic features of the excised mass proved to be helpful in assessing malignancy. Received: 3 July 1997; Revision received: 18 December 1997; Accepted: 28 April 1998     

Phyllodes tumors of the breast

Our objective was to study the color and pulse Doppler ultrasonography of phyllodes tumors of the breast. The data of 36 phyllodes tumors (19 benign, 5 borderline, and 12 malignant) were reviewed retrospectively. The median age of the patients was 41.5 years (range 13–62 years), and the tumors varied in size from 1.5 to 20 cm (median 4.6 cm). Most of the phyllodes tumors were lobulated masses with smooth margins, mildly hypoechoic internal echo texture, a heterogeneous internal echo pattern, and no microcalcification. Vessels were detectable on 35 of these tumors, with 51.4% having resistance index >0.700, 45.7% having pulsatility index >1.300, and 51.4% having V_max >15 cm/s. The color Doppler characteristics were of no significant use in predicting the histological nature of the phyllodes tumors. If the sonographic features suggest a phyllodes tumor, a histological examination should be conducted to confirm the diagnosis. Electronic Publication     

Macrocystic serous adenoma of the pancreas: radiologic-pathologic correlation

OBJECTIVE: Macrocystic serous adenoma is a rare benign pancreatic neoplasm, recently described in the pathology literature. We describe the CT and MR imaging features in a series of five consecutive pathologically proven cases. MATERIALS AND METHODS: Of seven cases fulfilling the pathology criteria for macrocystic serous adenoma over an 11-year period, five patients underwent preoperative CT and MR imaging at our institution. In addition to the clinical presentation and pathologic features of the tumor, the following CT and MR imaging features were reviewed: size and location; wall thickness; internal septations; and presence of mural nodules, papillary projections, or calcifications. RESULTS: All patients but one were women (age range, 36-78 years; mean age, 48.6 years). The sizes of the tumors ranged from 1.5 to 5.0 cm (mean, 3.1 cm). Three (60%) of five tumors were located in the pancreatic head. The wall measured less than 2 mm in four lesions and 4 mm in one. No mural nodules, papillary projections, or calcifications were present. Lesions were unilocular (n = 3) or bilocular (n = 2). Excellent correlation of imaging features with gross pathology was observed. CONCLUSION: On CT and MR imaging, the macrocystic variant of serous adenoma typically appears as a small (< 5 cm), uni- or bilocular cyst with a thin (< 2 mm) wall that lacks mural nodules or calcifications. The imaging appearance of macrocystic serous adenoma is distinctly different from that of microcystic serous cystadenoma, but the imaging appearance of macrocystic serous adenoma is indistinguishable from mucinous cystadenoma and cystadenocarcinoma of the pancreas.     

Characterization of lesions of the breast with proton MR spectroscopy: comparison of carcinomas, benign lesions, and phyllodes tumors

OBJECTIVE: Proton MR spectroscopy is a recently described technique with high sensitivity and specificity for differentiating breast carcinoma from benign lesions. We evaluated the possible relationship between spectroscopy results and the tumor proliferative index, angiogenesis, and HER2/neu oncogene overexpression. SUBJECTS AND METHODS. We prospectively evaluated 19 breast carcinomas, 21 benign breast lesions (including 18 fibroadenomas, one fibrocystic change, one hamartoma, and one papilloma), and six phyllodes tumors (four benign, two of borderline malignancy) using proton MR spectroscopy. All lesions were larger than 1.5 cm. Tumor Ki-67 proliferative index, tumor angiogenesis, and HER2/neu oncogene overexpression were evaluated by immunohistochemistry of the histologic material. RESULTS: Spectroscopy findings were positive in 17 (89%) of 19 carcinomas but negative for all benign lesions and phyllodes tumors (sensitivity, 89%; specificity, 100%). Significantly higher levels were obtained for all biologic parameters in carcinomas compared with benign lesions and phyllodes tumors. HER2/neu oncogene overexpression was present in 37% of carcinomas but not in other lesions. The two false-negative findings of breast carcinoma showed similar Ki-67 proliferative index and microvessel density compared with the remaining carcinomas, but both cases were negative for HER2/neu overexpression. CONCLUSION: Proton MR spectroscopy is useful in the in vivo characterization of breast masses when the lesion exceeds 1.5 cm in maximal dimension. Spectroscopy is unable to reveal benign breast lesions and phyllodes tumors of benign and borderline malignancy. We suggest that a false-negative spectroscopic result may be related to an absence of HER2/neu overexpression in carcinoma of the breast.     

Radiofrequency ablation of hepatic tumors: variability of lesion size using a single ablation device

OBJECTIVE: In this study, we examined the variability of lesion sizes produced by a single radiofrequency ablation using the same device and algorithm in patients with small malignant hepatic tumors. MATERIALS AND METHODS: A review of the clinical records of 208 patients who underwent radiofrequency ablation of malignant hepatic tumors during a 6-year period revealed 31 patients with small tumors that were treated with a single ablation. Clinical data were recorded using standardized work sheets. Tumor and lesion sizes after ablation were measured from CT scans. The influences of tumor size, tumor type, presence or absence of cirrhosis, and tissue temperature on the ablation size were analyzed. RESULTS: The size of tumor before treatment ranged from 0.8 to 4.0 cm (mean diameter [+/- SD] = 1.8 +/- 0.9 cm) with corresponding volumes of 0.27-30.24 mL (mean volume = 27.1 +/- 15.9 mL). The lesion sizes after ablation ranged from 1.7 to 5.3 cm (mean diameter = 3.6 +/- 0.7 cm) with corresponding volumes of 2.29-75.87 mL (mean volume = 4.9 +/- 7.1 mL). Tumor type (p > 0.25), presence or absence of cirrhosis (p > 0.45), and tissue temperature (p = 0.055) had no relationship to ablation size. Tumor size had a statistically significant influence on ablation lesion size (p < 0.04). Ablation of small tumors (diameter < or = 2.25 cm, n = 32) produced random lesion sizes whereas ablation of large tumors (diameter > 2.25 cm, n = 11) produced larger lesions (mean diameter = 4.0 +/- 0.8 cm). CONCLUSION: Significant variation occurs in the lesion size produced using the same ablation device and algorithm. These findings must be considered when planning ablation strategies.     

Askin瘤的影像诊断

目的:分析8例Askin瘤的影像征象。材料和方法:回顾性分析8例Askin瘤的胸部平片、B超和CT资料。年龄13~62岁,平均29.8岁。全组均拍摄正侧位胸片和CT扫描,6例胸壁肿瘤行B超检查。全组均经病理组织学和免疫组织化学检查证实。结果:6例原发于胸壁软组织,肿瘤较小(平均大小3cm),术后半数近期复发,复发灶平均大小为5.5cm。2例原发于纵隔,肿瘤平均大小为7cm。瘤实质主要为软组织,散在液化、坏死或出血。CT增强后扫描呈不规则强化。5例受累胸膜表现为不规则状、结节状增厚。结论:Askin瘤典型影像表现为胸壁、胸膜和纵隔病灶相互融合成巨大肿块。因此,面对青少年患者的胸部软组织肿瘤,鉴别诊断时应考虑到Askin肿瘤。     

MRI-guided percutaneous cryoablation of renal tumors: use of external manual displacement of adjacent bowel loops

PURPOSE: We sought to investigate retrospectively the safety and effectiveness of using external hand compression to displace adjacent bowel loops during MRI-guided percutaneous cryoablation of renal tumors. MATERIALS AND METHODS: Fourteen patients (six women, eight men; mean age: 72 years) with 15 renal tumors (mean diameter: 2.4 cm; range: 1.4-4.6 cm) adjacent to bowel were treated with MRI-guided percutaneous cryoablation during which bowel was displaced manually. Bowel loop of concern was ascending colon (n=5), descending colon (n=8), descending colon and small bowel (n=1), ascending colon and small bowel (n=1). To analyze effectiveness of the maneuver, mean distance between tumor margin and bowel before and after the maneuver were compared and analyzed using paired Student's t-test. Minimum distance between iceball edge and adjacent bowel with external manual displacement during freezing was also measured. Safety was assessed by analyzing post-procedural MR imaging for adjacent bowel wall thickening and focal fluid collections as well as patients' clinical and imaging follow-up. RESULTS: Mean distance between tumor margin and closest adjacent bowel increased from 0.8 cm (range: 0-2 cm) before external manual compression to 2.6 cm (range: 1.6-4.1 cm) with manual displacement (p<0.01). Mean minimum distance between iceball edge and closest adjacent bowel during the procedures was 1.6 cm (range: 0.5-3.5 cm). No evidence of bowel injury was encountered. Twelve of 15 tumors had follow-up (mean: 10 months) that showed no tumor recurrence. CONCLUSION: MRI-guided percutaneous cryoablation of renal tumors adjacent to bowel can be done safely and effectively using external hand compression to displace bowel loops.