肾血管平滑肌脂肪瘤的多层螺旋CT诊断

目的:探讨多层螺旋CT在肾血管平滑肌脂肪瘤诊断中的价值。方法:14例肾血管平滑肌脂肪瘤患者行多层螺旋CT扫描检查,并在工作站行MPR、MIP图像重建,分析肾血管平滑肌脂肪瘤的MSCT表现,并与手术病理结果对照。结果:14例肾血管平滑肌脂肪瘤CT平扫肿块均呈等、低、高低混杂密度,11例其中显示有脂肪密度,1例显示高密度出血灶。多期增强扫描皮质期肿块呈均匀或不均匀强化,但低于肾皮髓质强化,脂肪、坏死囊变、出血区无强化,分泌期肿块持续强化。MIP显示肿块内纡曲、增粗的血管。结论:多层螺旋CT能显示肾血管平滑肌脂肪瘤肿块内的脂肪成分及血管成分,多期增强扫描能了解肿块的强化方式,对肾血管平滑肌脂肪瘤的诊断具有重要价值。     

巨大肾血管平滑肌脂肪瘤自发性破裂大出血CT误诊4例分析

目的：探讨肾血管平滑肌脂肪瘤破裂出血手术前误诊的原因及CT手术前诊断该病的可能性。方法：复习手术与病理证实的4例术前CT误诊的巨大的肾血管平滑肌脂肪瘤伴破裂出血的病例。结果：巨大的肾血管平滑肌脂肪瘤可发生肿瘤内、肾筋膜囊内,盆腔膜后甚至腹腔内出血;仔细寻找肿块内代表脂肪成分的CT征是支持肾血管平滑肌脂肪瘤诊断的关键。误诊原因可能 与出血掩盖肿块内实际存在的脂肪征有关,也可能与将被挤到肿块的边缘的肿瘤内的脂肪结构误诊为肾筋膜囊内或肾窦内的脂肪有关,结论：巨大的肾血管平滑肌脂肪瘤可发生自发性破裂出血,手术前CT发现肿块内脂肪征是诊断的关键。     

肾血管平滑肌脂肪瘤的CT诊断与治疗(附35例分析)

目的:评价肾血管平滑肌脂肪瘤(angiolipoleiomyoma,ALL)的CT诊断价值及治疗方法。方法:分析35例肾血管平滑肌脂肪瘤的CT表现,并与29例手术病理结果对照。结果:肾血管平滑肌脂肪瘤患者多见于女性,外向性肾血管平滑肌脂肪瘤病灶较大,直径大于3cm,肿瘤出血及自发性破裂是本病最常见的严重并发症,23例多脂肪及少脂肪肾血管平滑肌脂肪瘤CT可作出诊断,脂肪成分很少或无脂肪的肾血管平滑肌脂肪瘤应结合B超、MRI诊断。结论:CT对肾血管平滑肌脂肪瘤及瘤内出血、自发性肾破裂多能作出明确诊断,对确定治疗方案有一定的指导作用。     

肾脏上皮样血管平滑肌脂肪瘤的螺旋CT表现及病理对照研究

目的：初步探讨肾脏上皮样血管平滑肌脂肪瘤的CT表现。方法：搜集4例经手术病理及免疫组化证实的肾上皮样血管平滑肌脂肪瘤,均行双肾螺旋CT平扫及动态增强扫描,回顾性分析其CT表现,并与手术病理对照。结果：2例CT平扫,含有明确脂肪密度,并呈侵袭性表现;增强扫描实性成分明显强化。2例病灶较小,平扫呈略高密度实性肿块,边界清楚,病灶内无明显脂肪密度;增强扫描密度相对均匀,实质期强化程度最高,排泄期密度下降较少。免疫组化均证实为上皮样肾血管平滑肌脂肪瘤。结论：肾脏上皮样血管平滑肌脂肪瘤即可富含脂肪,又可为乏脂肪病变,与经典血管平滑肌脂肪瘤在影像学上区分困难,当AML出现侵袭性表现,应考虑到肾脏上皮样血管平滑肌脂肪瘤。     

肝脏血管平滑肌脂肪瘤的CT诊断

目的:分析6例肝脏血管平滑肌脂肪瘤(HAMI)的CT表现,进一步提高该病诊断准确性.方法:所有病例均经手术病理证实,6例经螺旋CT检查,其中5例平扫加动态动静期及延迟期增强扫描,1例肝、肾血管平滑肌脂肪瘤合并结节性硬化,1例肝脏血管平滑肌脂肪瘤合并血管瘤.结果:5例病灶中含有脂肪密度影,1例痛灶未测及脂肪密度,5例病灶动静脉期呈点状、片状、条索状及分隔状明显强化,延迟期持续强化,中心及周边见点条状血管影.结论:病灶同时含有脂肪成分及血管影是HAML的CT特征性表现,结合CT薄层平扫及动态多期增强扫描,有助于提高该病诊断准确性.     

乏脂肪性肾血管平滑肌脂肪瘤MSCT表现

目的 探讨肾脏乏脂肪性血管平滑肌脂肪瘤多层螺旋CT(MSCT)表现,提高对该病的影像表现认识.方法 回顾性分析20例经手术病理证实的乏脂肪性肾平滑肌脂肪瘤MSCT及临床资料,重点分析病灶的大小、部位、形态、密度及血供情况等.结果 20例患者共有23个病灶,其中22个病灶均表现为实质性肿块,1个病灶为巨大囊性并出血.病灶最大的为11.5 cm×9 cm,最小的为0.8 cm×0.8 cm.左肾13个病灶,右肾10个病灶.其中10个病灶呈类圆形,11个病灶呈圆形,2个病灶呈菌伞状,5个病灶见劈裂征;平扫12个病灶呈均匀略高密度,11个病灶呈等密度.8个病灶内见少量脂肪成分,余病灶薄层(1 mm)未见脂肪成分.20个病灶在CT动态增强肾皮质期呈明显不均匀强化,1个病灶呈环形强化,2个病灶呈均匀强化.增强扫描呈明显强化的病灶20个,轻中度强化病灶2个.增强皮质期多呈明显不均匀强化,实质期及延迟早期呈均匀强化,强化较肾实质弱,其内脂肪密度无强化.结论 乏脂肪性肾血管平滑肌脂肪瘤在CT平扫薄层显示细微脂肪成分具有特征性诊断价值;对于乏脂肪性血管平滑肌脂肪瘤延迟早期呈均匀强化,以及自肾脏实质发出粗大的血管穿行于病灶的征象有助于鉴别诊断.     

肾血管平滑肌脂肪瘤的CT诊断

目的：探讨肾血管平滑肌脂肪瘤的CT表现,以提高诊断水平.方法：回顾性分析19例肾血管平滑肌脂肪瘤患者的临床资料并探讨其CT诊断及鉴别诊断.结果：本组19例中,CT检查发现含脂肪成分者16例,其中常规层厚扫描发现脂肪成分12例,薄层扫描发现（常规扫描不能确定的）脂肪成分4例;CT检查无明显脂肪成分者3例.结论：CT对肾血管平滑肌脂肪瘤诊断的关键是在肿瘤中测得脂肪密度影,对于含脂肪成分较多的肾血管平滑肌脂肪瘤可明确定性诊断,对于少脂或无脂的肾血管平滑肌脂肪瘤,薄层CT扫描可提高诊断准确率.     

肾血管平滑肌脂肪瘤的CT诊断

目的探讨肾血管平滑肌脂肪瘤（AML）的CT表现,提高术前CT诊断水平。方法回顾性分析21例（女性12例,男性9例）经手术、病理证实的肾血管平滑肌脂肪瘤临床和CT资料。结果本组21例中．15例CT表现为含脂肪成分的混杂密度肿块,5例表现为稍低密度或混杂密度肿块,1例表现为高密度肿块;18例为单发病变（左侧11例,右侧7例）,3例多发病灶。结论CT对肾血管平滑脂肪瘤的确诊取决于病灶中的脂肪成分,对含较多脂肪成分的肾AML能明确定性诊断,对少脂肪成分的肾AML散在点状低密度影有助于定性诊断。     

合并出血的肾血管平滑肌脂肪瘤的多层螺旋CT诊断

目的：提高对合并出血的肾血管平滑肌脂肪瘤的诊断准确率。方法：回顾性分析13例经手术病理证实为肾血管平滑肌脂肪瘤合并出血的患者CT资料,观察其影像学表现。结果：发生于左肾者8例,右肾者4例,1例为双侧者。病灶最大者达25 cm,最小者约3 cm。所有病灶内均可见出血,部分合并肾包膜下或肾周出血。增强后病灶内脂肪成分及出血无强化,实性成分可见轻至中度强化。所有病灶内均可见血管影。4例病灶突破肾包膜,2例同时合并肾周感染。结论：多层螺旋CT尤其是增强检查,对合并出血的肾血管平滑肌脂肪瘤的诊断极有价值。     

肝脏血管平滑肌脂肪瘤的CT、MRI分型诊断价值及其病理基础

目的:探讨肝脏血管平滑肌脂肪瘤的CT、MRI分型诊断价值及其病理基础.方法:收集经临床和病理资料证实的肝脏血管平滑肌脂肪瘤21例,分析其CT、MRI征象,探讨CT、MRI对各型的分型诊断价值及其病理基础.结果:21例均行CT扫描,其中12例行MR检查.血管瘤型4例,病理上以粗大扭曲的异常血管或血管瘤为主,CT、MR增强扫描异常血管或血管瘤动脉期呈明显强化,门脉期强化程度仍高于同期肝实质.肌瘤型3例,病理上以平滑肌成分为主,脂肪成分很少(<10%).CT平扫为较均匀低密度,MRI T1WI呈低信号,T2WI呈稍高信号;CT、MRI增强扫描动脉期呈明显强化,门脉期、延迟期呈持续强化.脂肪瘤型5例,病理上以脂肪成分为主(≥70%),CT、MRI显示脂肪密度或信号.混合型9例,CT平扫为含有脂肪的混杂密度,MRI T1WI病灶主体呈不均匀低信号,脂肪成分呈高信号,T2WI呈混杂高信号,CT、MRI增强扫描其内软组织成分动脉期呈明显强化,门脉期仍有强化.病理上血管、平滑肌、脂肪3种成分比例接近(其中脂肪成分占10%～70%).免疫组化:上述21例均显示HMB45(+)、SMA(+).结论:CT、MRI能较好地反映肝脏血管平滑肌脂肪瘤的分型和各型的病理特征,具有一定的诊断特异性.     

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.