小肠内疝CT表现（附11例分析）

目的探讨螺旋CT对小肠内疝诊断的临床应用价值。方法对11例经手术证实的小肠内疝患者的临床及CT影像资料进行回顾性分析,所有患者均经全腹部CT平扫及增强扫描。结果 11例患者均有小肠梗阻的CT征象,表现为不同程度肠管或肠袢聚集、移位,肠系膜血管走行异常,腹腔积液等。结论小肠内疝的CT表现具有一定特征性,对于进一步提高该病诊断率具有重要临床价值。     

腹内疝伴肠扭转的螺旋CT诊断

目的:探讨螺旋CT对腹内疝及伴发肠扭转的诊断价值.方法:对10例手术证实的腹内疝病例的CT资料进行回顾性分析,CT检查采用平扫及双期增强,并进行VR、MPR及M1P等后处理.结果:10例腹内疝中,8例有腹部手术史,10例均表现为肠梗阻,8例显示疝口,并有肠聚集、移位、肠系膜血管走形异常.伴发肠扭转7例,显示肠管和血管的“漩涡征”,5例见“鸟喙征”,3例见“同心圆征”,4例出现肠绞窄,表现为肠管强化减弱、肠壁水肿、腹水.结论:螺旋CT增强扫描和多种方法重组对腹内疝伴发肠扭转具有重要的诊断价值,及时诊断对患者的预后具有重要的作用.     

肠扭转的CT表现

目的 提高螺旋CT诊断肠扭转的正确率。方法 对9例术前CT明确诊断为肠扭转，并经手术证实病例的CT资料进行分析。主要重组方法有多平面重组法（MPR）及滑动薄层块最大强度投影法（STS-MIP）。结果 9例肠扭转诊断均正确，主要征象有肠管的“漩涡征”（6例）和血管的“漩涡征”（9例）、“靶环征”（2例）、“鸟喙征”（6例）。结论 肠系膜血管的“漩涡征”是诊断肠扭转的特异性征象，“靶环征”及肠壁强化减弱、腹水是提示绞窄性梗阻的可靠征象。螺旋CT扫描及重绢对肠扭转的诊断具有莺要价值。     

腹内疝的临床与CT表现(附8例分析)

目的:探讨腹内疝的临床特点和CT表现。方法:回顾性分析经手术证实的8例腹内疝患者的临床特点和CT表现。结果:8例中十二指肠旁疝3例,2例术前诊断正确,1例误诊为肠扭转;5例经肠系膜疝中4例有腹部手术史。8例患者的CT表现中共同征象包括肠梗阻,小肠异常聚集,肠系膜血管异位、伸拉、聚集或扩张。其他肠管移位。左侧十二指肠旁疝表现为胃和胰尾间或胰尾后方囊袋状异常排列的肠管;右侧十二指肠旁疝表现为十二指肠圈部位囊袋状肠管伴肠系膜血管紊乱;经肠系膜疝表现为小肠异常排列,无大网膜脂肪覆盖,结肠中心性移位,常伴小肠梗阻或肠绞窄。5例经肠系膜疝的CT征象均能明确或高度提示内疝。结论:腹内疝的CT表现有一定特征性,CT可对大多数病例作出明确诊断。     

绞窄性肠梗阻肠系膜及其血管改变的CT研究

目的对经CT检查、有肠系膜及其血管（MRV）改变的30例绞窄性肠梗阻（SO）进行分析，探讨CT诊断的临床价值。方法30例SO，均行CT平扫，其中20例行增强扫描，均显示有不同形式的MRV改变。26例经手术、4例经临床证实，包括粘连性肠梗阻9例，肠扭转8例，肠套叠6例，肠系膜血管闭塞性肠梗阻4例，内疝3例。结果所有病例经CT检查可发现11种CT征象，并可分作：（1）直接征象：包括肠系膜血管闭塞2例，肠系膜水肿及其血管增粗并形态异常19例；（2）间接征象：包括肠壁水肿增厚24例，CT强化肠壁异常6例，肠腔大量积液13例，肠袢特殊形态10例，肠壁、肠系膜出血各1例；（3）并发症征象：包括肠壁间积气3例，肠系膜门脉积气1例，肠系膜积气1例，腹水和气腹共11例。结论急腹症CT检查如能显示MRV改变，结合其他CT征象和临床，可以对SO术前作出诊断。同时也能观察到传统x线不能显示的并发症。     

螺旋CT对肠扭转的诊断价值

目的：探讨螺旋CT对肠扭转的诊断价值。方法：回顾性分析11例术前CT明确诊断并经手术证实为肠扭转的临床及影像资料。结果：11例肠扭转CT均正确诊断,其中6例为360°肠扭转,4例为270°肠扭转,1例为180°肠扭转。除全部11例都有通常的肠梗阻征象外,主要征象还有“漩涡征”（9／11）、“靶环征”（4／11）及“鸟喙征”（10／11）,肠系膜血管也可以形成“漩涡征”（11／11）。结论：螺旋CT对肠扭转具有重要的临床价值,尤其是肠系膜血管的“漩涡征”。     

CT定位诊断腹腔内卵巢源性和小肠系膜源性囊性病变的价值

目的探讨螺旋CT对腹腔内卵巢源性和小肠系膜源性囊性病变的定位诊断价值。资料与方法回顾性分析18例临床资料和CT资料完整的卵巢源性和小肠系膜源性囊性病变,均经手术病理证实。着重观察肿块与十二指肠水平段的关系、肠系膜上血管有无移位、系膜血管有无包绕、生殖血管有无增粗、肿块有无卵巢血管蒂,以及肿块的后方有无空肠和回肠等。结果(1)5例小肠系膜囊性病变中,肿块上缘位于十二指肠上缘上方层面3例,肠系膜上血管移位4例,系膜血管包绕4例,肿块后方无空/回肠5例。(2)13例卵巢源性病变中,肿块上缘位于十二指肠上缘上方层面5例,肠系膜上血管移位4例,一侧生殖静脉增粗8例,卵巢血管蒂征显示8例,病变后方显示空/回肠11例。结论依据观察肿块上缘与十二指肠上缘的关系,肠系膜血管有无包绕,生殖血管有无增粗,卵巢血管蒂征的有无,肿块后方有无空肠和回肠显示等征象,以及肿块的CT特点,可对腹腔内卵巢源性和小肠系膜源性囊性病变作出定位诊断。     

肠系膜原发性肿瘤和囊性病变的CT表现

目的 探讨小肠系膜、横结肠系膜和乙状结肠系膜原发性肿瘤及囊性病变的螺旋CT表现.资料与方法 回顾性分析13例肠系膜原发性肿瘤及囊性病变患者的临床及CT影像资料,均经手术病理证实.其中,单纯囊肿2例,淋巴管瘤3例,纤维瘤病3例,低分化癌1例,平滑肌肉瘤2例,纤维肉瘤1例,非霍奇金淋巴瘤1例.着重观察病变与邻近结构的关系及其CT表现特征.结果 13例中,1例平滑肌肉瘤为多发,其余均为单发病灶.12例单发病变中,11例病变的轴位最大径均＞6cm,其中,病变上缘超过十二指肠水平段上缘者8例;肠系膜上静脉/肠系膜上动脉(SMV/SMA)移位7例;系膜血管被包绕7例;肠系膜血管在病变处汇聚4例;邻近肠管向前方和两侧移位9例,病变包绕肠管2例.13例CT表现各异.结论 肠系膜原发性肿瘤和囊性病变,根据其CT表现特点及与周围血管和肠管的关系,可做出定位诊断;对其中部分病变还可做出定性诊断.肠系膜原发性肿瘤和囊性病变较少见,采用螺旋CT,尤其是多层螺旋CT并结合三维重组技术,可做出较准确诊断.     

64层螺旋CT在肠道急腹症病因诊断中的价值

目的：探讨64层螺旋CT在肠道急腹症病因诊断中价值。方法：对46例经手术或临床证实的肠道急腹症病例资料行64层螺旋CT平扫加增强扫描,并进行回顾性分析。主要重组方法为多平面重组（MPR）、最大密度投影（MIP）及容积再现（VR）。结果：46例病例中,肠道肿瘤22例、肠道炎性病变11例、憩室5例、淋巴瘤2例、肠系膜上静脉血栓1例、肠坏死1例、麻痹性肠梗阻伴全内脏转位1例、单纯性肠扭转1例、腹壁疝及闭孔疝各1例;其中64层螺旋CT准确诊断（定位定性）40例,诊断符合率87.0%,4例结肠癌误诊为炎性病变,漏诊脂肪瘤及肠穿孔各1例。结论：64层螺旋CT扫描及重组图像对肠道病变显示直观、准确,对肠道急腹症的病因诊断具有重要的诊断价值。     

多层螺旋CT及后处理技术对肠系膜上动脉栓塞的诊断价值

目的：探讨多层螺旋CT（MSCT）及其后处理技术对肠系膜上动脉栓塞（SMAT）的诊断价值。方法：经CTA诊断为肠系膜上动脉栓塞及继发性改变的11例患者,均经DSA或手术证实。所有病例均行螺旋CT增强扫描,并采用多平面重组（MPR）、曲面重组（CPR）、最大密度投影（MIP）、容积再现（VR）等方法进行后处理。对SMAT的CTA表现及肠系膜、肠管等的继发性表现进行观察分析。结果：11例CT增强扫描表现均为肠系膜上动脉增粗和血管腔内充盈缺损。可见肠腔扩张、积气、积液和／或液-气平面7例,肠壁变薄2例,肠壁增厚及强化程度减低或不强化8例;肠系膜水肿5例,肠系膜积液2例;气体集聚2例,分别位于肠壁、肠系膜内及腹腔。结论：MSCT能够对肠系膜上动脉栓塞及继发病变进行快速、及时、准确地诊断,并能判断肠管缺血的程度,与DSA及手术所见相符,是诊断肠系膜血管栓塞性病变的有价值的影像学方法。     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.     

MR imaging of disorders of the brachial plexus

The authors evaluated 64 consecutive patients with suspected brachial plexus (BP) abnormalities of diverse cause with magnetic resonance (MR) imaging, using the body coil and a standardized protocol. Of the 43 patients for whom follow-up was available, 25 were suspected of having neoplastic involvement of the BP, nine had sustained injuries, and nine presented with BP symptoms of uncertain cause. MR imaging was 63% sensitive, 100% specific, and 77% accurate in demonstrating the abnormality in this diverse patient population. When patients with neoplastic and traumatic disorders were considered separately, sensitivity increased to 81%, accuracy to 88%, and specificity remained unchanged. In the patients with a clinical diagnosis of idiopathic or viral plexitis, the MR imaging findings were normal, serving to exclude other structural abnormalities. It is concluded that MR imaging is valuable in the assessment of a wide range of BP disorders.     

MR imaging characteristics of noncancerous lesions of the prostate.

Radical prostatectomy specimens from 53 men with clinical stage A or B prostate cancer were retrospectively reviewed and compared with correlative axial T2-weighted magnetic resonance (MR) images obtained just before surgery. Non-cancerous lesions were evaluated for signal intensity and location. Focal high-signal-intensity areas (n = 72) were present in 81% of patients. The 26% of lesions seen in the central gland all correlated with cystic atrophy. Of the 53 lesions seen in the peripheral prostate, 47 (89%) were cystic atrophy without associated cancer, four (7.5%) cystic atrophy with cancer, and two (3.8%) focal inflammation. Focal low-signal-intensity areas (n = 42) were present in 60% of patients. Of the 31% of lesions in the central prostate, one-fifth correlated with benign prostatic hyperplasia (BPH) and four-fifths with fibrous tissue. Of the 69% of peripheral lesions, 83% corresponded to fibrous tissue, 10% to BPH, and 7% to normal tissue. Mixed lesions (n = 42) were present in 64% of patients; 86% of these were located centrally and 14% peripherally. All mixed central lesions were BPH; the peripheral lesions were areas of combined cystic atrophy and fibrosis. BPH of low or mixed signal intensity can extend into the peripheral prostate and mimic cancer. High-intensity cystic atrophy associated with cancer can mimic normal tissue.     

肾细胞癌的MRI研究进展

肾细胞癌是最常见的成人肾脏恶性肿瘤。近年来，多种功能MRI成像技术（如扩散加权成像、灌注加权成像等）、多参数MRI联合分析以及影像组学等新兴影像处理技术被证实在肾细胞癌的诊断中具有较大的价值。目前，研究热点多集中于良恶性肿瘤的鉴别、组织学亚型的区分、肿瘤分期、预测核分级及判断预后。就MRI新技术及图像处理技术在肾细胞癌中的研究进展予以综述。     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Influence of in vivo copper on MR images of the liver in rats

To investigate the effects of in vivo copper on magnetic resonance (MR) images, the authors studied Long-Evans cinnamon rats, which develop hepatitis and hepatocellular carcinoma as a result of abnormal copper metabolism. The livers of the rats were imaged before hepatitis developed; the absence of hepatic disease was confirmed histopathologically. The copper that accumulated in the liver of the rats was thought to exist in the form of divalent ions, which were suspected of reducing the T1 and T2 of neighboring protons. However, the signal intensities of the liver on T1- and T2*-weighted images did not change, suggesting that in vivo copper, even when accumulated abnormally, does not influence the signal intensity of MR images.     

Techniques for high-resolution MR imaging of atherosclerotic plaque

Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.     

Dynamic MRI of the gallbladder lesions: Differentiation of benign from malignant

Forty-nine pathologically proven gallbladder lesions were evaluated in 45 patients using dynamic MRI with a spoiled gradient pulse sequence (SPGR), to access the ability of this technique to differentiate benign from malignant gallbladder lesions. The studies were reviewed retrospectively. Signal intensity of the lesions were measured. Twenty-one malignant and 28 benign lesions were classified into three categories: polypoid, diffuse wall thickening, and exophytic. Early and delayed enhancement patterns were evaluated. For the polypoid masses, malignant lesions (n = 9) demonstrated early and prolonged enhancements, whereas benign lesions (n = 14) had early enhancement with subsequent washout (P < .05). For diffuse gallbladder wall thickening, malignant lesions (n = 6) demonstrated early and prolonged enhancement and benign lesions (n = 14) showed relatively slow, prolonged enhancement (P < .05). The exophytic masses (n = 6) all were malignant and demonstrated early and prolonged enhancement. Dynamic MRI can help differentiate benign from malignant gallbladder lesions.