MSCT灌注成像在肺部孤立性结节的良恶性鉴别诊断中的应用

肺部孤立结节(SPN)的种类较多,其中大部分为肺癌,区分其良恶性是临床的主要目的,也是诊断的难点[1],MSCT灌注成像作为一种新的功能成像技术已成为对SPN进行研究的热点.本文对53例SPN病例的MSCT灌注成像的多项灌注参数及拟合时间-密度曲线(TDC)进行分析研究,旨在探讨MSCT灌注成像在SPN的良、恶性鉴别诊断中的应用价值.     

18F-FDGPET/CT代谢显像在结直肠癌患者孤立性肺结节中的应用

【摘要】目的：探讨18F-FDGPET/CT显像对结直肠癌患者孤立性肺结节的临床诊断价值。方法：回顾性分析经病理诊断为结直肠癌（CRC）且PET/CT显像发现孤立性肺结节的59例患者的病例资料,其中男36例,女23例,年龄33~91岁,中位年龄（58.4±13.3）岁。分析SPN的部位、直径、最大标准摄取值（SUVmax）,依据病灶的SUVmax值及CT形态特征综合判定病灶的性质,并与最终诊断结果（组织病理学诊断或长期临床随访结果）进行对照分析。结果：59例中32例最终诊断为恶性SPN,其中27例PET/CT显示为阳性;良性SPN27例,24例PET/CT显示为阴性。PET/CT对于结直肠癌患者SPN的诊断敏感度、特异度、符合率及阳性和阴性预测值分别为84.38%、88.89%、86.44%、90.00%及82.76%。恶性SPN的平均直径为（13.00±6.46）mm,良性SPN为（5.48±6.48）mm,两组间差异有统计学意义（t=－4.448,P<0.001）直径为5.5mm时具有最大诊断效能。恶性SPN的SUVmax为3.30±2.17,良性SPN为1.19±1.30,两组间差异有统计学意义（t=－4.609,P<0.001）,以SUVmax值1.15作为诊断良恶性结节的阈值时诊断效能最大。患者的年龄和病灶的发生部位对SPN良恶性的判断无统计学意义。结论：18F-FDGPET/CT显像对于结直肠癌患者孤立性肺结节的检出及良恶性判断具有很高的敏感性和特异性,当结节直径大于5.5mm或SUVmax大于1.15时提示病灶为恶性可能性较大。     

分类决策树辅助CT诊断孤立性肺结节的方法学研究

目的 应用分类与回归决策树(CART)算法构建CT显像鉴别良恶性孤立性肺结节(SPN)预测模型,探讨数据挖掘技术在SPN影像诊断中的应用价值.方法 分别提取12个临床指标和22个CT征象指标作为CART预测SPN良恶性的输入指标.连续性纳入自2003年7月至2006年7月间经病理证实的SPN,且术前行CT检查的患者116例,其中良性结节62例,恶性结节54例.采用CART建立用于预测良恶性SPN的分类决策树模型,并通过交互印证的方法计算该模型的诊断准确性.同时设低年资医师诊断组和高年资医师诊断组,采用盲法进行独立阅片判断SPN的良恶性.采用受试者操作特征(ROC)曲线比较3组间的诊断效能.结果 (1)成功建立了能够判断SPN良恶性的CART诊断模型,其中含有8条诊断规则,最低相对错误代价为0.199,CART对SPN具有决策意义的最重要的前3位决策指标为结节的毛刺征、患者年龄和病灶部位.(2)CART、高年资医师和低年资医师对SPN良恶性诊断的ROC曲线下面积分别为0.910±0.029、0.827±0.038、0.612±0.052.CART与低年资医师ROC曲线下面积差(DBF)=0.297,P＜0.01;与高年资医师DBF=0.083,P＜0.05;高年资医师与低年资医师DBF=0.214,P＜0.01.CART诊断效能高于高年资医师和低年资医师,高年资医师高于低年资医师.结论 CART是具有强大学习能力的数据挖掘工具,可以对SPN的良恶性进行正确判断,为实现人工智能在影像诊断中的应甩提供重要的方法学依据.     

螺旋CT动态增强扫描对孤立性肺结节定性诊断的价值

目的:分析良恶性孤立性肺结节(SPN)的动态强化特点,探讨动态SCT增强扫描对SPN定性诊断的价值。方法:对50例SPN患者进行螺旋CT同层动态增强扫描,对比剂总量100ml,注射流率3ml/s,延迟15s开始扫描,至180s结束,测量结节中心增强前后的CT值,分析最大强化值及时间-密度曲线(TAC),全部病例经手术病理证实。结果:肺炎性结节及恶性结节均显著强化,肺炎性结节强化峰值的时间较肺癌结节延迟。恶性结节的TAC表现为陡峭的上升支后有一较长的平台期,炎性结节的TAC表现为上升支平缓,部分见降支。结核球等其它良性SPN无明显强化。结论:动态SCT增强扫描对SPN定性诊断有较高价值。SPN的强化峰值及TAC形态有助于良、恶性病变的鉴别诊断。     

低剂量CT在肺孤立性结节诊断中的研究与应用

肺孤立性结节(solitary pulmonary nodule,SPN)是指发生于肺部、直径≤3cm的孤立性结节,无肺不张、肺部炎症及其他疾病,临床上常见。随着低剂量螺旋CT对肺癌筛查的研究及应用,越来越多的SPN被筛检出来,尤其那些直径小、良恶性影像征象模糊的结节,而肺部孤立性结节的良、恶性鉴别,与患者的治疗及预后密切相关。CT在SPN的探查和良恶性鉴别中起着重要作用。而低剂量CT较常规CT在满足诊断需求的同时,还能有效减低单次检查和多次随访检查的剂量,在辐射剂量与诊断图像质量之间找到最佳平衡点。     

18F-FDG PET/CT对不同大小孤立性肺结节的诊断价值

目的 评价18F-脱氧葡萄糖(FDG) PET/CT对不同大小范围孤立性肺结节(SPN)良恶性鉴别诊断的价值.方法 从全国拥有PET/CT的10家医院筛选出已经获得病理学检查结果的SPN病例,收集诊断CT、PET/CT和病理检查结果以及标准摄取值(SUV)、结节大小等资料.诊断CT、PET/CT结果为肺癌、肺癌可能性大、肺癌可能者为阳性;结果为良性病变、良性可能性大、良性可能者为阴性;难以确定阳性和阴性者为不确定.采用SPSS 10.0软件对资料进行分析.结果 120个(120例)SPN中良性结节28个,恶性结节92个.直径或(长径+短径)/2≤1.0cm的结节17个,恶性病变9个;1.1～2.0cm 57个,恶性病变占75.44%;2.1～3.0cm 46个,恶性病变占86.96%.28个良性结节SUV最大值(SUVmax)的平均值为4.5±4.9, SUV平均值(SUVmean)的平均值为2.9±3.6;92个恶性结节SUVmax平均值为6.7±4.2, SUVmean平均值为4.9±3.6;良性结节的SUV显著低于恶性结节的SUV.无论良性还是恶性结节,随着结节的增大,SUV升高.诊断CT对结节良恶性鉴别的灵敏度为78.26%,特异性3/8,准确性72.22%; PET/CT灵敏度为94.51%,特异性64.00%,准确性87.93%.结论 18F-FDG PET/CT在SPN鉴别诊断中具有较高的灵敏度、特异性和准确性,优于诊断CT;结节大小是判断SPN良恶性的重要指标,直径或(长径+短径)/2＞2.0cm的结节,恶性可能性约为87%; SUV可以作为鉴别诊断的依据,但鉴于良性结节SUVmean的平均值为2.9±3.6,界值2.5仅供参考,尤其是对于≤1.0cm的结节.     

双能CT对孤立性肺结节的诊断价值

目的:探讨双能CT对孤立性肺结节(SPN)的诊断价值.方法:采用双能CT(管电压为80和140kVp)对水模、体模、47例平扫CT无明显钙化的SPN(恶性31例,良性16例)进行扫描,测量其CT值变化,计算病灶内钙质含量,比较良恶性SPN的CT值变化及钙质含量.结果:良性SPN的CT值变化中位数为5HU,恶性SPN为4...     

99Tcm-depreotide显像对肺部病灶的鉴别诊断价值

Depreotide是一种人工合成的十肽生长抑素类似物,含生长抑素受体结合序列和99Tcm配位序列.通过荟萃分析肺部病灶的99Tcm-depreotide显像资料显示,99Tcm-depreotide鉴别肺部病灶良恶性的灵敏度为94.2%(95%可信区间:90.5%,97.9%),特异度为61.2%(95%可信区间:50.7%,71.7%),诊断准确率为81.6%,阳性预测值为81.1%,阴性预测值为83.2%;对于1.5 cm以下的孤立性肺结节(SPN),99Tcm-depreotide显像特异性极高,显像阳性是手术治疗的适应证;对于1.5 cm以上的SPN,因其灵敏度高,99Tcm-depreotide显像阴性者可进行系列CT扫描随访观察.     

螺旋CT三维成像技术对孤立性肺结节的应用价值

目的:探讨三维重建成像对孤立性肺结节(SPN)形态特征的显示及其良恶性的诊断价值。方法:对37例SPN(直径<3cm)进行增强薄层扫描,利用三维成像软件用表面遮盖法(SSD)进行三维重建,调整阈值上、下限,分别观察结节的表面形态及与相邻胸膜、支气管、血管的关系,分析三维形态学改变对鉴别其良恶性的诊断价值。结果:3D CT完整显示了37例SPN立体形态和结节与周围血管的关系及血管类型,直观显示34例SPN相邻胸膜内外侧面形态改变和结节与周围支气管的关系,3D CT形态分型,在良恶性SPN上有差异。结论:三维重建技术不仅能三维显示SPN的异常表现,而且能显示结节与支气管、血管和胸壁是的解剖关系及形态学特征。3D CT结合2D CT有助于提高诊断准确性,是鉴别SPN良恶性的有效的影像学检查方法。     

螺旋CT薄层扫描并MPVR重建对孤立性肺结节的诊断价值

目的:探讨螺旋CT肺薄层扫描并多层面重建对孤立性肺结节的诊断价值。方法:对86例SPN患者进行螺旋CT规范化检查,并使用多层面重建(MPVR)技术重建观察。病灶结节直径选在0.8~3.0cm,病历均经临床手术或肺穿刺活检病理证实。其中恶性59例,均为原发性肺癌,包括腺癌25例、鳞癌17例、细支气管肺泡癌10例、小细胞未分化癌7例;良性病变27例,包括结核灶13例、炎性假瘤9例、错构瘤5例。结果:86例SPN的CT征象中,分叶征和棘突或毛刺征多出现于恶性结节,与病理和随访结果对比,螺旋CT薄层扫描并MPVR重建判断肺小结节良恶性的准确率、灵敏度、特异性、阳性预测值和阴性预测值分别为75.6%、76.3%、74.1%、86.5%、58.8%。结论:SCT肺薄层扫描并MPVR重建能显示更多的SPNCT征象,对SPN的良恶性诊断有较高的诊断价值。     

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 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 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 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.     

Localized proton MR spectroscopy of the brain in children

Small-voxel (3.0–8.0 cm³), magnetic resonance (MR) imaging–guided proton MR spectroscopy was performed in 54 patients (aged 6 days to 19 years) with intracranial masses (n = 16), neurodegenerative disorders (n = 34), and other neurologic diseases (n = 4) and in 23 age-matched control subjects without brain disease. A combined short TE (18 msec) stimulatedecho acquisition mode (STEAM) and long TE (135 and/or 270 msec) spin-echo point-resolved spatially localized spectroscopy (PRESS) protocol, using designed radio-frequency pulses, was performed at 1.5 T. STEAM spectra revealed short T2 and/or strongly coupled metabolites; prominent resonances were obtained from N-acetyl aspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Lactate was well resolved with the long TE PRESS sequence. Intracranial tumors were readily differentiated from cerebrospinal fluid (CSF) collections. All tumors showed low NAA, high Cho, and reduced tCr levels. Neurodegenerative disorders showed low or absent NAA levels and enhanced mobile lipid, glutamate and glutamine, and inositol levels, consistent with neuronal loss, gliosis, demyelination, and amino acid neuro-toxicity. Preliminary experience indicates that proton MR spectroscopy can contribute in the evaluation of central nervous system abnormalities of infants and children.     

Percutaneous needle biopsy of the spine

The purpose of this review article is to provide a brief overview of the recent literature on the two main types of percutaneous biopsy methods done in the spinal column: fine needle aspiration biopsy (FNAB) and core needle biopsy (CNB). FNAB is the process of obtaining a sample of cells and bits of tissue for examination by applying suction through a fine needle attached to a syringe. Core needle biopsy involves extracting a cylindrical sample of tissue using a large, hollow needle. The decision for needle biopsy is a joint effort between the clinician, pathologist, radiologist, surgeon, and patient. Specific techniques and approaches with varying needle systems are described for each spinal region. Percutaneous image-guided spine biopsy is a safe and effective procedure. It is the procedure of choice in definitive diagnosis of pathologic lesions of the spine.