螺旋CT及其图像处理技术对喉部肿瘤侵犯的诊断价值

目的：将横断面图像,多平面重建（MPR）图像和仿真内窥镜（VE）图像结合起来综合评价喉部肿瘤的侵犯范围。方法：20例拟诊喉及下咽癌的患者行术前前瞻性螺旋CT检查并行图像后处理（MPR和VE）。采用盲法阅片,将横断面图像结果与横断面,MPR,VE联合图像结果分别与手术病理结果对照。结果：联合图像对评价室带,声带,前联合,声门下,甲状软骨,喉外结构受侵的总敏感性,特异性,准确性分别为：100％,98．5．％,99．2％,横断面图像分别为：92．4％,89．5％,90．8％;两者比较其特异性,准确性在统计学上差异有显著性意义（P值分别为：0．028,0．003）。对于杓状软骨,声门旁间隙及会厌前间隙的评价,联合图像与横断面图像结果一致。结论：对室带,声带,前联合,声门下,甲状软骨,喉外结构的受侵采用横断面结合MPR和(或）VE有助于提高诊断水平,对于杓状软骨,声门旁间隙及会厌前间隙,目前MPR及VE对诊断尚不能提供更多帮助。     

多层螺旋CT及后处理技术在颈部动脉受侵判断中的价值

目的：评价多层螺旋CT横断面扫描像、MPR及VR技术对颈部动脉受侵判断的准确性，探讨后处理技术在颈部肿瘤侵犯颈部动脉方面的应用价值。方法：使用8层螺旋CT扫描机，对临床拟诊颈部动脉旁肿瘤的患者行前瞻性直接增强扫描，其中手术证实恶性肿瘤患者40例(48个肿物)。两位医师对40倒手术患者的横断面扫描图像、MPR图像(包括AVE重组、MIP重组、CUR重组)、VR图像中53支颈部动脉是否受侵进行双盲法评价．对比手术及病理结果后给予评分，进行统计学分析。结果：对颈部动脉(包括颈动脉和锁骨下动脉)受侵的判断，MPR的敏感性、特异性和准确性分别为100％、92．1％和94．3％，敏感性较横断面提高了6．7％(P=1．000)，特异性与横断面相仿(P=1.000)．准确性与横断面相同(94．3％)。对动脉受侵的诊断价值，MPR和血管VR的应用价值达≥3分者分别占71．7％和14．2％(P=0．000)；MPR中3种重组方法的价值相仿(P=0．817)。结论：对动脉受侵的判断，MPR可为判断颈部动脉受侵提供重要的补充信息，增强诊断信心，横断面图像仍是判断颈部动脉受侵的基本方法。     

64层CT多向调整多平面重组诊断长骨病变的价值

目的前瞻性研究64层CT的多向调整多平面重组（MPR）在长骨病变中的应用价值，及其替代直接扫描横断面图像及平片的可能性。方法对平片发现的长骨病变进行64层CT各向同性扫描，然后进行MPR成像，并进行MPR多方向调整，使病变显示于长骨的冠状及矢状长轴面上。其中50例进行了手术并有病理诊断结果，就其长轴面MPR图像、直接扫描CT横断面图像、平片对病变的诊断符合率进行对比，并对比长轴面MPR与直接扫描横断面CT的图像数量。结果64层CT多向调整的长轴面MPR对病变的诊断符合率为96％（48／50例），高于直接扫描CT横断图像（72％，36／50例）及平片（80％，40／50例），3种方法比较，差异有统计学意义（X^2=10．71、6．06，P值均〈0．05），而图像数量明显少于横断面CT（MPR50幅图像，横断面CT300幅图像）。结论多向调整的长轴面MPR解决了多层CT图像数量庞大的问题，并提高了诊断符合率，是长骨病变CT诊断的趋势。     

多层螺旋CT征象诊断周围型非小细胞肺癌的临床研究

目的探讨多层螺旋CT征象在周围型非小细胞肺癌（non-small cell lung cancer,NSCLC）临床诊断中的应用价值。方法选择在我院经手术及病理证实的周围型非小细胞肺癌患者进行多层螺旋CT检查、多平面重建（multi-plan reconstruction,MPR）、表面遮盖显示（shaded surfaee display,SSD）、遮盖容积再现（shaded volume rendering,SVR）重建图像并进行分析,旨在提高对其CT征像的认识与诊断正确率。结果采用MPR重建后对分叶征、毛刺征、血管集束征、胸膜凹陷征、空洞征、胸膜受侵征等征象检出率均高于薄层扫描,但是其中MPR重建后对分叶征、毛刺征、血管集束征等征象检出率则明显高于薄层扫描,且差异具有统计学意义（X^2=4．05、4．66、4．61,Pd0．05）。采用SVR重建后无空洞征检出,而对分叶征、毛刺征、血管集束征、胸膜凹陷征、胸膜受侵征等征象检出率均高于薄层扫描,但是其中SVR重建后血管集束征检出率则明显高于薄层扫描,且差异具有统计学意义（X^2=7．O1,Pd0．05）。采用SSD重建后无空洞征检出,而在显示周围型非小细胞肺癌分叶征、毛刺征、血管集束征、胸膜凹陷征、胸膜受侵征等主要征象上敏感性均高于横断面薄层扫描,但是其中SSD重建后对胸膜凹陷征检出率则明显高于薄层扫描,且差异具有统计学意义（X^2=5．07,P〈O．05）。结论对周围型非小细胞肺癌患者进行MPR、SSD、SVR等三种不同的图像后处理,对分叶征、血管集束征及胸膜凹陷征征的显示敏感性显著提高。     

18F-FDG PET/CT对非小细胞肺癌术前T及N分期的价值

目的 比较^18F—FDG PET／CT与CT在非小细胞肺癌（NSCLC）原发灶（T）及淋巴结（N）分期中的价值。方法 以术后病理诊断为标准，比较30例NSCLC患者^18F-FDG PET／CT与CT在T及N分期中的诊断效能。结果 ^18F—FDG PET／CT和CT在T分期中准确性分别为86．7％，73．3％（P〉0．05）；对115站胸内淋巴结的诊断灵敏度、特异性及准确性分别为68．8％，95．2％，87．8％和43．8％，88．0％，75．7％，2种方法准确性差异有统计学意义（P〈0．05）；对65站纵隔淋巴结诊断灵敏度、特异性、准确性分别为90．5％，97．7％，95．4％和57．1％，81．8％，73．8％，2种方法准确性差异有统计学意义（P〈0．01）；在N分期中准确性分别为76．7％，66．7％（P〉0．05）。结论 ^18F—FDG PET／CT融合图像较CT更有助于NSCLC术前T和N分期，尤其在纵隔淋巴结的诊断中明显优于CT。     

CT的分叶征表现在肺内孤立结节影像诊断中的价值

目的探讨CT的分叶征表现在肺内孤立结节影像诊断的价值以及CT多平面重组（MPR）对此征检出的意义。方法观察病理证实的周围型小肺癌137例及良性肺内结节45例，将结节的边缘分为4型。对28例肺癌、22例良性结节行MPR，考察其显示分叶征的作用。引入可能性比值（likelihood ratios，LR）以量化良恶性病变在形态学上存在重叠的表现。结果Ⅰ型边缘结节对良性病变的特异性为83．3％（20／24），敏感性为44．4％（20／45）。Ⅳ型边缘结节对周围型小肺癌的特异性为97．6％（83／85），敏感性为60．7％（83／137）。表明Ⅰ型边缘是良性病变的特点；而Ⅳ型边缘是恶性病变的特征。Ⅳ型边缘的结节恶性病变在MPR重组图像上的检出率为64．3％（18／28），与横断面扫描差异有统计学意义（P〈0．01）。结论分叶征对肺内孤立结节的诊断有价值，MPR配合横断面薄层图像有助于提高该征的检出率。     

64层CT脊髓造影多平面重组对颈神经根损伤的诊断价值

目的前瞻性研究64层CT的脊髓造影（CTM）多平面重组（MPR）在颈神经根损伤中的诊断价值及其替代直接扫描横断面图像及常规X线脊髓造影的可能性。方法对26例临床诊断为颈神经损伤患者进行X线脊髓造影和64层CT各向同性扫描，然后进行MPR成像，并进行MPR多方向调整，使病变显示于冠状、矢状和横断面上。其中26例（54个神经根）进行了手术探查并有术后诊断结果，就其冠状、矢状断面MPR图像、直接扫描CT横断面图像、脊髓造影平片对病变的诊断符合率进行对比，并比较横断面MPR与直接扫描横断面CT的图像数量。结果以患侧蛛网膜下腔内颈神经根前后支走行区和神经孔处充盈缺损消失，连续性无神经根显示为直接征象，CTM发现神经根损伤31个。间接征象表现为：（1）创伤性脊膜膨出：椎管内患侧硬膜囊膨大、变形，呈柱形高密度影，并可沿椎间孔向外延伸，形成神经根鞘膜囊肿，与蛛网膜下腔间有低密度的细线状分隔，在撕裂水平可见29个膨出。（2）蛛网膜囊肿：硬膜囊一侧膨大变形，呈囊样扩张，病变未经椎间孔向外延伸，与蛛网膜下腔间有细线状分隔26个。（3）蛛网膜下腔不对称：一侧腔变窄，脊髓有不同程度的移位，多层面显示各神经根走行区未见连续性充盈缺损17个。64层CT多向调整的冠状面MPR对病变的诊断符合率为92，6％（50／54个），高于直接扫描CT横断图像（77.8％，42／54个）及平片（68．5％，37／54个），3种影像方法与术后诊断结果进行Kappa一致性检验比较，X线平片、CTM横断面和曲面冠状MPR的Kappa值分别为0．686、0．772、0．920，P值均〈0．05。可见曲面冠状MPR与手术诊断结果高度一致。而图像数量明显少于横断面CT（MPR50幅图像，横断面CT400幅图像）。结论多向调整的冠状面MPR解决了多层CT图像数量庞大的问题，该方法省时、易行，可直观清晰显示颈神经根损伤范围，提高了诊断符合率。     

16层螺旋CT诊断肺动脉栓塞的临床价值

目的：探讨16层螺旋CT对肺动脉栓塞的诊断价值。方法：回顾性分析经临床确诊为肺动脉栓塞的23例患者的16层螺旋CT资料,分析PE的直接征象、间接征象及分型,比较常规横断面图像、MPR、VR和MIP图像对栓子的显示效果。结果：23例患者CT共发现栓子345个,其中中心型栓子67个,附壁环型115个,完全闭塞型37个,不完全闭塞型126个。间接征象包括马赛克征2例,肺梗死3例,胸腔积液5例,肺动脉高压5例。横断面图像共检出栓子345个,MPR共检出320个,与横断面图像比较,MIP和VR图像对栓子的显示效果（分别为164和82个）相对较差（P〈0．05）,尤其是对肺叶及其以下肺动脉分支内栓子的显示效果明显低于横断面组（P〈0．05）。结论：16层螺旋CT能清楚显示肺动脉栓子,MPR、MIP及VR等图像重组方法是诊断肺栓塞的重要辅助方法,结合使用可提高诊断的准确性。     

多层螺旋CT及其后处理技术在评价颈部肿瘤气管侵犯中的应用研究

目的　评价多层螺旋CT及其后处理技术在评价颈部肿瘤气管侵犯的应用价值 ,探讨颈部肿瘤气管侵犯的诊断标准。资料与方法　对 2 0例颈部气管旁恶性肿瘤患者 (2 2个肿瘤 )行前瞻性的术前CT检查 ,3位医师双盲法评价横断面扫描图像、多平面重建 (MPR)和容积再现 (VR)图像上颈部肿瘤与气管的关系 ,对比手术及病理结果 ,进行统计学分析。结果　对气管受侵的判断 ,MPR的准确性 (90 .9% )与横断面 (86 .4 % )相仿 (P =1.0 0 0 ) ;对气管受侵的诊断价值 ,气管MPR和VR评分≥ 3分者分别占 6 8.2 %、2 2 .7% (P <0 .0 1) ;肿瘤与气管交角≥ 90°时气管受侵多于交角 <90°时 (P <0 .0 5 )。结论　对气管受侵的判断 ,横断面是基本诊断方法 ,MPR可为横断面提供重要的补充信息 ,气管VR价值有限 ,MPR对判断气管受侵的应用价值高于气管VR。     

64层螺旋CT结合多平面重建诊断早期胃癌的价值

目的探讨64层螺旋CT横断位结合多平面重建（MPR）对早期胃癌的检出价值。方法回顾性分析30例经病理证实的早期胃癌的CT影像特征,由2名有经验的放射诊断医师分别评估轴位及MPR重建图像对早期胃癌的检出率,意见不同时通过协商达成一致。结果30例患者中,轴位图像检出18例,其检出率18／30;结合MPR图像检出26例,检出率26／30,两者之间的检出率差异有统计学意义（P=0．020）;单纯CT横断位图像T分期准确性为26．67％（8／30）,结合MPR图像T分期准确性为63％（19／30）,两者比较差异有统计学意义（χ2=8．148,P=0．004）。结论64层螺旋CT横断位结合MPR图像能提高早期胃癌的检出率及术前分期的准确性。     

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.