多层螺旋CT对冠状动脉粥样硬化斑块的显示结果及与超声结果的比较

目的评价多层螺旋CT（MSCT）探查无明显管腔狭窄的冠状动脉粥样硬化斑块的能力及准确性。方法共35例连续患者行冠状动脉内超声（IVUS）及16层MSCT检查，其中30例MSCT成像成功。对94支无明显狭窄的冠状动脉节段MSCT及IVUS图像行对照研究，逐一分析每支冠状动脉节段是否出现粥样硬化斑块。IVUS根据斑块回声特点将斑块分为钙化斑块、纤维斑块和软斑块，MSCT则测量斑块密度，以CT值表示。结果对照IVUS结果，MSCT对出现任何粥样硬化斑块节段的诊断敏感性为82．1％（46／56），特异性为89．5％（34／38）。对于含钙化斑块的节段，MSCT诊断敏感性为92．1％（35／38），特异性为96．4％（54／56）。对于含非钙化斑块的节段，MSCT诊断敏感性为73．2％（30／41），特异性为88．7％（47／53）。对于仅含非钙化斑块的节段，MSCT诊断敏感性为66．7％（12／18）。MSCT分析54个斑块平均CT值，按照IVUS分类，钙化斑块19个，纤维斑块19个，软斑块16个，对应CT值分别为：钙化斑块（489±169）HU（196～817HU），纤维斑块（69±21）HU（25～117HU）以及软斑块（23±18）HU（-12～47HU）。非参数Kruskal-Wallis检验显示3组斑块MSCT测量密度CT值间差异有统计学意义（P值均〈0．01）；两种方法对斑块面积的测量具有相关性（r=0．58，P〈0．01），MSCT测定斑块平均面积为5．3mm^2，IVUS为5．6mm^2。结论MSCT对无明显管腔狭窄的冠状动脉粥样硬化斑块有良好的探查能力。根据斑块密度（CT值）差异，MSCT能区分不同类型冠状动脉粥样斑块。对斑块面积测量，MSCT与IVUS结果具有相关性。     

64层MDCT评价冠脉粥样硬化斑块的准确性:与IVUS对照研究

目的:评价64层MDCT在判断冠脉粥样硬化斑块性质及测量血管大小、斑块负担的应用价值。方法:14例患者经MDCT显示的位于冠脉近、中段的粥样硬化斑块作为研究对象,在斑块的最大层面测量斑块的CT值,根据CT值将斑块分类。并测量、计算最小管腔面积、血管外膜面积,斑块面积、斑块负荷。以IVUS为金标准,分别计算MDCT判断斑块性质的敏感性、特异性及各类斑块的平均CT值,并对血管测量进行统计学分析。结果:14例患者粥样硬化斑块25个,软斑块11个,纤维斑块7个,钙化斑块7个,平均CT值分别为49±32HU,93±23HU,1138±350HU。MDCT对脂质、纤维和钙化斑块诊断的敏感性和特异性分别为90.9%和92.9%;85.7%和94.4%;100%和100%。MDCT测量的管腔面积、血管面积、斑块面积、斑块负荷高于IVUS测量的结果,但两者之间没有统计学差异。结论:64层MDCT是一种准确无创的诊断和测量冠脉粥样硬化斑块的工具。     

冠状动脉粥样硬化斑块的64层CT冠脉造影评价

目的:探讨64层CT对冠状动脉粥样硬化斑块的识别能力及各种类型斑块在CT血管造影(CTA)上的密度差异。方法:16例冠状动脉内超声(ICUS)检查阳性患者纳入研究,年龄49～73岁。全部病例在ICUS后72小时内进行CTA检查(Philips Brilliance 64层螺旋CT,回顾性心电门控采集模式,层厚0.67mm)。对照ICUS所观察的24个节段进行分析,逐一记录每个斑块的位置、CT值及组织分型,同时以10mm/段计算无动脉粥样硬化的正常血管段数,并与ICUS结果一一对照,统计分析64层螺旋CT识别斑块的敏感性以及识别正常血管段的特异性,并根据ICUS对斑块的组织学分型计算各型斑块的CT值。结果:对照研究的24个节段ICUS共发现27个斑块,其中软斑5个,中间斑块8个,钙化斑块8个,混斑6个。64层螺旋CT能正确探查出其中26个斑块,漏诊中间斑块1个,敏感性为96.3%。不含斑块的以10mm为单位长度的节段共34个,冠状动脉CTA正确识别了其中33个节段,特异性为97.1%。CTA共发现26个斑块,对照ICUS对斑块的组织学分型,软斑的平均CT值为(46±16)HU,中间斑块为(121±50)HU,钙化斑块为(712±268)HU,软斑、中间斑块及钙化斑块三者的CT值间差异存在统计学意义(P<0.05)。结论:64层CT冠脉造影能有效检测冠状动脉粥样硬化斑块,一定程度上可取代ICUS。钙化斑块密度较高,CTA上易于同中间斑块和软斑区分,但后两者之间不易区分。     

非小细胞肺癌动态CT增强值与正电子发射计算机体层摄影脱氧葡萄糖标准摄取值的相关性探讨

目的探讨非小细胞肺癌动态CT增强值与正电子发射计算机体层摄影(PET)中18氟-脱氧葡萄糖(18F-FDG)标准摄取值(SUV)的相关性。方法搜集行PET-CT和动态增强CT检查的28例非小细胞肺癌和13例良性肺结节病例,测量结节增强前后各时相的平均CT值、18F-FDG标准摄取值的最大值和平均值,计算结节增强峰值,用Pearson相关分析方法评价良恶性结节动态CT增强峰值和18F-FDG SUV的相关性。结果非小细胞肺癌和良性结节CT增强峰值[(35·09±11·41)、(26·92±19·98)HU]的差异无统计学意义(t=1·374,P=0·189),SUV最大值(7·23±4·38、2·97±2·80)差异有统计学意义(t=-3·972,P<0·001),SUV平均值差异有统计学意义(t=-4·061,P<0·001)。非小细胞肺癌CT增强峰值[(35·09±11·41)HU]和18F-FDG SUV的平均值(4·93±3·53)及最大值(7·23±4·38)之间均无相关关系(r=-0·040,P=0·839及r=0·056,P=0·778)。结论非小细胞肺癌动态CT增强值与FDG SUV之间无相关关系,FDG SUV可能不适用于非小细胞肺癌抗肿瘤血管生成治疗的疗效评价。     

99Tcm-Ap4A显像探测动脉粥样硬化斑块的动物实验研究

目的探讨应用二磷酸腺苷(ADP)的类似物99Tcm-四磷酸二腺苷(Ap4A)显像探测动脉粥样硬化斑块的可行性.方法采用酒石酸亚锡还原99TcmO-4标记Ap4A,柱层析纯化,纸层析鉴定放射化学纯度.观察99Tcm-Ap4A在昆明小鼠体内的生物分布并测定动脉粥样硬化模型家兔病灶斑块/血液、病灶斑块/无斑块动脉壁的放射性比值,进行腹主动脉宏观放射自显影及正常家兔及动脉粥样硬化家兔体外体内显像.结果99Tcm-Ap4A的放射化学纯度为85%～91%.99Tcm-Ap4A在小鼠血液内清除迅速.注射99Tcm-Ap4A后30min粥样硬化组靶/血比值达3.17±1.27,靶/非靶比值为5.23±1.87.粥样硬化组自显影胶片上的曝光黑影与肉眼可见的动脉粥样硬化斑块有良好的一致性.体外显像正常家兔组腹主动脉未显影,粥样硬化组腹主动脉放射性浓聚清晰可见.体内显像粥样硬化组家兔的腹主动脉在注射99Tcm-Ap4A后15～30min与正常家兔组相比放射性浓聚明显增强,并持续到注药后3h.结论99Tcm-Ap4A是一种有潜力的可快速显示动脉粥样硬化斑块形成的显像剂.     

99Tcm-Ap4A显像探测动脉粥样硬化斑块的动物实验研究

目的　探讨应用二磷酸腺苷 (ADP)的类似物99Tcm 四磷酸二腺苷 (Ap4A)显像探测动脉粥样硬化斑块的可行性。方法　采用酒石酸亚锡还原99TcmO- 4 标记Ap4A ,柱层析纯化 ,纸层析鉴定放射化学纯度。观察99Tcm Ap4A在昆明小鼠体内的生物分布并测定动脉粥样硬化模型家兔病灶斑块 血液、病灶斑块 无斑块动脉壁的放射性比值 ,进行腹主动脉宏观放射自显影及正常家兔及动脉粥样硬化家兔体外体内显像。结果　99Tcm Ap4A的放射化学纯度为 85 %～ 91%。99Tcm Ap4A在小鼠血液内清除迅速。注射99Tcm Ap4A后 30min粥样硬化组靶 血比值达 3.17± 1.2 7,靶 非靶比值为 5 2 3± 1.87。粥样硬化组自显影胶片上的曝光黑影与肉眼可见的动脉粥样硬化斑块有良好的一致性。体外显像 :正常家兔组腹主动脉未显影 ,粥样硬化组腹主动脉放射性浓聚清晰可见。体内显像 :粥样硬化组家兔的腹主动脉在注射99Tcm Ap4A后 15～ 30min与正常家兔组相比放射性浓聚明显增强 ,并持续到注药后 3h。结论　99Tcm Ap4A是一种有潜力的可快速显示动脉粥样硬化斑块形成的显像剂。     

18F-FDG PET/CT显像正常腹部消化器官的标准摄取值分析

目的分析^18F-脱氧葡萄糖（FDG）PET/CT显像正常腹部消化器官标准摄取值（SUV）的变化范围.方法60例要求行PET/CT检查的健康人,按体重7.77 MBq/kg静脉注射^18F-FDG,PET采集为三维模式,每个床位3 min.对腹部肝、胆囊、脾、胰腺、胃、盲肠、结肠和直肠进行半定量分析,各器官的SUV由横断面测量,准确定位时参考同机CT.结果正常腹部消化器官^18F-FDG摄取有较大差异,其中摄取较高者SUV平均值（SUVavg）依次为直肠、肝、乙状结肠、回盲部和脾、升结肠,SUV最大值（SUVmax）依次为直肠、乙状结肠、肝、回盲部、升结肠、脾.结论PET/CT显像能较好地识别腹部消化器官;熟悉正常腹部消化器官^18F-FDG摄取的差异,对判读图像十分重要.     

晚期乳腺癌18F-FDG PET-CT显像标准摄取值与预后的相关性

目的 探讨晚期乳腺癌18 F-FDG PET-CT显像标准摄取值与预后的相关性.方法 选择68例晚期乳腺癌患者,记录诊断时PET-CT的SUV值,均给予全身静脉化疗,以SUV值8为分界点,将本组患者分为两组,随访5年,观察SUV值与5年生存率的关系.结果 本组观察的68例患者,SUV值越小,生存期相对越长,反之,生存期则相对较短.结论 18F-FDG PET-CT显像标准摄取值(SUV值)对乳腺癌的预后有一定价值,值得临床进一步研究.     

冠状动脉粥样斑块的多层螺旋CT与病理的对照研究

目的:探讨多层螺旋CT检测和区分冠状动脉粥样硬化斑块的准确性。方法:搜集 4 例成人心脏标本,从冠状动脉内注入对比剂,将标本行 16 层螺旋 CT(MSCT)冠状动脉成像,检测非钙化斑块的形态和密度,并与病理对照。结果:4例标本中,MSCT显示冠状动脉斑块8处,与病理所见斑块的位置和数目一致。脂质丰富的 3 例冠状动脉粥样斑块CT值分别为(25±6) HU、(47±9) HU和(28±7) HU。5例纤维丰富的冠状动脉粥样斑块CT值分别为(87±9) HU、(68±8) HU、(78±11) HU、(97±9) HU和(83±10) HU。部分血管节段内充满血凝块,其 CT值平均为(35±6) HU。结论:多层螺旋CT可用于发现冠状动脉斑块,通过检测斑块 CT值的不同反映斑块的主要成分,从而可区分冠状动脉斑块的性质。     

基于CT冠状动脉周围脂肪测量对冠状动脉非钙化斑块风险分层的价值初探

目的:探讨基于冠状动脉周围脂肪衰减指数(FAI)测量对不同狭窄程度及不同CT值的非钙化斑块进行风险分层的相关性研究。方法:回顾性分析269例临床拟诊冠心病患者的冠状动脉CT血管造影图像,根据管腔狭窄程度分为四组,包括正常组60例、轻度组104例、中度组63例和重度组42例(病变组冠状动脉均仅存在非钙化斑块)。测量病变组各支冠状动脉的非钙化斑块CT值,根据斑块CT衰减值分为三组,包括低衰减组21例(CT值≤30 HU)、中等衰减组84例(300.05),FAI值差异具有统计学意义(P<0.05),病变组FAI值明显高于正常组。不同CT衰减值的非钙化斑块FAI值差异具有统计学意义(P<0.05),低衰减组与中高衰减组FAI差异明显(P<0.05),但中等衰减组与...     

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.