MSCT肺血管成像对肺动脉栓塞的诊断价值

目的:探讨多层螺旋CT肺血管成像对肺动脉栓塞的诊断价值.方法:对24例肺动脉栓塞病例行多层螺旋CT肺动脉成像检查,图像采用1.0mm层厚、0.7mm层间距和0.75mm层厚、0.5mm层间距进行重建,CTPA后处理采用容积再现(VRT)、最大密度投影(MIP)和多平面重建(MPR),对重建的图像进行对照分析、比较优缺点.结果:24例病例中,病变共累及76支肺动脉,其中,主肺动脉6支、肺叶动脉36支、肺段动脉27支、亚段动脉7支.肺动脉栓塞病变显示,1.0mm及0.75mm层厚重建无显著性差异意义.结论:多层螺旋CT肺动脉成像具有安全、快速、无创优点,对肺动脉栓塞诊断特异性强、敏感性高,可作为肺动脉栓塞的首选检查方法.     

小儿支气管异物低剂量CT扫描条件及图像质量分析

目的评价多层螺旋CT低剂量扫描条件对小儿支气管异物图像质量的影响。方法将60例误吸异物的患儿随机分成三组行低剂量CT扫描,CT扫描参数:管电压分别为80/100/120kV,管电流均为30m As,准直器1.5mm,螺距1.15,重建轴位、斜冠状位及VR图像。用方差分析对3组患儿的年龄及扫描参数中各组剂量长度乘积(DLP)进行比较分析,图像质量评价数据用构成比χ~2检验。结果三组患儿年龄无统计学差异,三组患儿CT扫描剂量长度乘积有显著性差异,三组患儿CT图像质量评分无统计学差异。结论在低管电流条件下,降低CT扫描管电压(80kV),可以进一步降低辐射剂量,而不影响图像质量。     

桥小脑角囊性病变的MRI诊断及鉴别诊断

目的：探讨MRI对桥小脑角（cerebellopontine angle,CPA）囊性病变的诊断及鉴别诊断价值。方法：搜集本院30例经病理证实的CPA囊性病变患者的MRI资料,回顾性分析这些病变的MRI表现,并和手术病理结果作对照分析。结果：30例病变中右侧CPA 16例,左侧10例,双侧4例;位于CPA池内24例,脑内6例。其中表皮样囊肿12例,多呈不规则形沿蛛网膜下腔匐行生长,并包埋邻近的神经血管,DWI以高信号为主,增强后无强化;蛛网膜囊肿5例,信号与脑脊液一致,增强后无强化;皮样囊肿3例,呈长T1长T2信号2例,混杂信号1例,2例DWI呈高信号,均无强化表现;囊性听神经瘤6例,呈单房或多房改变,增强后囊壁及分隔均见强化,其中3例患侧内听道扩大、听神经增粗并强化;血管母细胞瘤4例,均为大囊小结节型,附壁结节明显强化。与手术及病理对照,MRI对CPA囊性病变的定位、定性诊断准确率分别为96%、92%。结论：MRI对CPA囊性病变的定位及定性诊断准确率高,具有重要的诊断及鉴别诊断价值。     

螺旋CT在胰腺癌诊断中的价值及临床应用

目的：探讨螺旋CT在胰腺癌中的诊断价值及临床应用。方法：回顾性分析了48例胰腺癌患者螺旋CT图像，扫描时间为注射对比剂后40－55s和60s左右，并依照正常胰腺组织和肿瘤在平扫和两期的增强情况、CT征象行术前评估，再与手术结果对照。结果：胰腺－肿瘤增强密度差异值平均分别为胰腺期49.10HU、门静脉期27.0HU，两期差异有显著意义（t=2.543、P＜0.01)。肿块在胰腺期能够清晰显示。25例术前认为可切除的肿瘤，术中仍有7例不能切除。结论：螺旋CT双期扫描能够明显提高胰腺癌的诊断准确率并为临床提供有价值的术前评估。     

多排螺旋CT血管成像评价肾动脉变异

目的探讨多排螺旋CT动脉成像（MSCTA）对肾动脉变异的诊断价值。方法分析298例肾动脉CT成像患者的肾动脉变异情况,并对男、女发生率和左、右肾发生率行χ2检验。结果肾动脉解剖变异发生率为60.47%（179/296）,其中单侧发生率为44.59%（132/296）,双侧发生率为15.88%（47/296）;异位开口发生率22.97%（68/296）;副肾动脉、早发支、肾极动脉的发生率分别为36.82%（109/296）、25.00%（74/296）、41.55%（163/296）。男性与女性、左肾与右肾的变异发生率没有明显差异（P〉0.05）。结论 MSCTA能够清晰显示供肾动脉各级分支数目、起点、走行和入肾部位,对于外科手术、尤其是肾移植具有重要的指导意义。     

多层螺旋CT在强直性脊柱炎骶髂关节病变中的应用价值

目的:探讨多层螺旋CT在强直性脊柱炎(AS)骶髂关节病变的应用价值。方法:56例临床确诊为强直性脊柱炎患者行骶髂关节多层螺旋CT检查,观察骶髂关节病变的CT表现及影像学特征。结果:强直性脊柱炎骶髂关节病变的多层螺旋CT表现特征为病变主要累及骶髂关节的髂骨侧,表现为关节软骨钙化、关节面毛糙、骨性关节面下多发小囊状骨质吸收、破坏伴不同程度骨质增生硬化,骶髂关节间隙狭窄、消失、关节骨性融合及骶髂韧带钙化等。结论:多层螺旋CT对强直性脊柱炎(AS)骶髂关节病变的诊断与鉴别诊断具有重要的应用价值。     

64层螺旋CT冠状动脉成像临床应用

目的：探讨64层螺旋CT（MSCT）冠状动脉成像方法显示冠状动脉狭窄的能力及可靠性。方法：对26例临床怀疑冠心病的患者行心脏冠状动脉CT成像（CTA）并与常规冠状动脉造影（CAG）结果进行比较分析。结果：以冠状动脉血管造影（CAG）为金标准,冠状动脉CTA影像判断血流动力学相关性冠状动脉狭窄（≥50%）的敏感度0.933、特异度0.974、准确度0.968、阳性预测值0.857、阴性预测值0.989。结论：64层螺旋CT冠状动脉成像是一种无创、简便、优良的冠状动脉成像方法,可作为冠状动脉粥样硬化的筛选手段及冠状动脉术后复查的首选方法。     

双源CT虚拟平扫在头部检查的初步应用

目的 探讨双源CT双能量头部虚拟平扫(VNC)的图像质量和临床应用价值.方法 对62例临床怀疑脑血管病变的患者,使用双源CT进行头部常规平扫(CNC)和双能量CTA检查,利用双能量软件得到VNC图像.比较CNC和VNC图像灰质、白质、脑脊液、高密度出血性和低密度缺血性病变的CT值,使用4分法对图像质量进行主观评价,比较两组图像的噪声、辐射剂量和病变检出率,使用配对t检验、Wilcoxon符号秩检验和χ2检验(McNemar检验和Kappa检验)进行统计分析.结果 CNC与VNC图像灰质、白质、脑脊液、高密度病变及低密度病变的CT值分别为[(43.3±1.5)和(33.2±1.3)HU,t=46.98]、[(32.9±1.3)和(28.8±1.6)HU,t=16.28]、[(9.0±1.4)和(5.3±1.9)HU,t=12.41]、[(62.8±10.0)和(51.3±11.5)HU,Z=-4.37]、[(20.7±4.7)和(18.0±6.9)HU,t=3.84],差异均有统计学意义(P值均＜0.01).VNC图像噪声[(1.63±0.34)HU]大于CNC图像[(0.99±0.18)HU](Z=-6.41,P＜0.01).VNC图像有效剂量[(0.53±0.08)mSv]低于CNC[(1.37±0.23)mSv](Z=-6.45,P＜0.01).CNC和VNC图像噪声、颅底伪影、灰白质对比、高密度和低密度病变显示的主观评分分别为(3.9±0.3)和(2.7±0.5)分、(3.7±0.5)和(2.4±0.9)分、(3.3±0.6)和(1.3±0.5)分、(4.0±0.0)和(3.0±0.4)分、(3.9±0.3)和(3.2±0.8)分,VNC图像噪声与颅底伪影的评分较CNC图像低(Z值分别为-6.84、-6.15,P值均＜0.01),灰白质对比、高密度和低密度病变显示低于CNC图像(Z值分别为-7.01、-4.52和-3.12,P值均＜0.01).在个体水平,VNC图像显示高密度出血性病变29例,无假阳性和假阴性病例,敏感性、特异性、阳性预测值和阴性预测值均为100.0%(29/29、33/33、29/29、33/33),与CNC一致(P＞0.05,Kappa值=1.000);VNC图像显示低密度缺血性病变22例,假阳性1例,假阴性2例,敏感性、特异性、阳性预测值和阴性预测值分别为91.3%(21/23)、97.4%(38/39)、95.5%(21/22)和95.0%(38/40),与CNC图像(23例)差异无统计学意义(χ2=0.00,P＞0.05,Kappa值=0.895).在病灶水平,VNC图像显示出血灶53个,假阴性4个,无假阳性,敏感性、特异性、阳性预测值和阴性预测值分别为93.0%(53/57)、100.0%(38/38)、100.0%(53/53)和90.5%(38/42),VNC图像对出血灶的显示率与CNC差异无统计学意义(χ2=2.25,P＞0.05,Kappa值=0.914);VNC图像显示低密度病灶38个,假阳性2个,假阴性13个,敏感性、特异性、阳性预测值和阴性预测值分别为73.5%(36/49)、96.4%(53/55)、94.7%(36/38)和80.3%(53/66),VNC图像对低密度病灶的显示率低于CNC(χ2=6.67,P＜0.01,Kappa值=0.707).结论 与CNC相比,头部VNC辐射剂量低,但图像质量下降,对出血性病变具有替代CNC的潜在使用价值,对缺血性病变也有一定的参考价值.

Abstract：

Objective To investigate image quality and clinical value of dual-source dual energy virtual non-contrast (VNC) CT of the head. Methods Sixty-two patients suspected of cerebrovascular diseases underwent conventional non-contrast (CNC) CT and dual energy CTA examination of the head with dual-source CT. Virtual non-contrast images were reconstructed using dual energy software. The CT values of gray matter, white matter, cerebrospinal fluid, hyperdense hemorrhagic lesion and hypodense ischemic lesion were compared between CNC and VNC images. A four-score scale was used to assess image quality subjectively. Image noise, radiation dosage and detection rate were compared between CNC and VNC images. Paired t test, Wilcoxon signed ranks test and Chi-square test (McNemar test and Kappa test) were used. Results The CT value on CNC and VNC images, were (43. 3 ± 1.5) and (33. 2 ± 1.3) HU for gray matter (t = 46.98, P ＜ 0. 01), (32. 9 ± 1.3) and (28.8 ± 1.6) HU for white matter(t = 16. 28, P ＜0.01), (9.0 ± 1.4) and (5.3 ± 1.9) HU for cerebrospinal fluid (t=12.41, P＜0.01),(62.8 ±10.0) and (51.3 ± 11.5) HU for hyperdense lesion (Z = -4.37, P ＜ 0.01), (20.7 ±4.7) and (18.0 ±6. 9) HU for hypodense lesion (t = 3. 84, P ＜ 0. 01), respectively. VNC images[(1.63 ±0.34) HU]had more noise than CNC images[(0.99±0.18) HU](Z= -6.41, P＜0.01). VNC [(0. 53 ± 0. 08) mSv]had less effective dose than CNC[(1.37 ± 0. 23) mSy](Z= - 6. 45, P ＜ 0. 01).In subjective assessment, VNC images had more noise (2. 7 ± 0. 5 for VNC and 3.9 ± 0. 3 for CNC,Z = -6. 84, P ＜ 0. 01) and skull base-related artifacts (2. 4 ± 0. 9 for VNC and 3.7 ± 0. 5 for CNC,Z = -6. 15, P ＜0. 01) than CNC images. The gray/white matter contrast (1.3 ± 0. 5 for VNC and 3.3 ±0. 6 for CNC, Z = - 7. 01, P ＜ 0. 01), hyperdense lesion display (3.0 ± 0. 4 for VNC and 4. 0 ± 0. 0 for CNC,Z = -4. 52, P ＜ 0. 01) and hypodense lesion display (3.2 ± 0. 8 for VNC and 3.9 ± 0. 3 for CNC,Z= -3. 12, P ＜0. 01) on VNC images were lower than those on CNC images. In per-patient analysis,29 cases of hyperdense lesion (hemorrhage) were found on VNC images without misdiagnosis. The sensitivity, specificity, positive predictive value and negative predictive value were all 100. 0% (29/29,33/33, 29/29, 33/33). VNC images had the same detection rate of hyperdense lesions as CNC images (P ＞0. 05, Kappa = 1. 000) at per-patient level. Twenty-two patients with hypodense ischemic lesions were found on VNC images with one false positive case and two false negative cases. The sensitivity,specificity, positive predictive value and negative predictive value were 91.3% (21/23), 97.4%(38/39), 95.5% (21/22) and 95.0% (38/40) respectively. No statistical difference was found in detecting hypodense lesions between VNC and CNC images (χ2 = 0. 00, P ＞ 0. 05, Kappa = 0. 895). In per-lesion analysis, 53 hemorrhage lesions were found on VNC images with false negative results of four lesions and no false positive result. The sensitivity, specificity, positive predictive value and negative predictive value were 93.0% (53/57), 100. 0% (38/38), 100. 0% (53/53) and 90. 5% (38/42)respectively. There was no significant difference in detection rate of hyperdense lesion between VNC and CNC images (χ2 =2. 25, P ＞0. 05, Kappa =0. 914). Thirty-eight hypodense lesions were found on VNC images with 2 false positive lesions and 13 false negative lesions. The sensitivity, specificity, positive predictive value and negative predictive value were 73.5% (36/49), 96.4% (53/55), 94. 7% (36/38)and 80. 3% (53/66) respectively. The detection rate of hypodense lesion on VNC images was lower than that on CNC images (χ2 = 6. 67 ,P ＜ 0.01, Kappa = 0. 707). Conclusion Compared with CNC images,head VNC images have reduced image quality and radiation dosage. VNC images can replace CNC images potentially in detecting intracranial hemorrhage and provide information for ischemic cerebrovascular diseases to some extent.     

MRI和MRCP在胰胆管恶性梗阻性病变中的定性研究

目的:研究磁共振成像(MRI)和磁共振胰胆管成像(magnetic resonance cholangiopancreatography,MRCP)在恶性胰胆管梗阻性疾病中的应用价值。方法:使用先进的Siemens Avanto 1.5T磁共振扫描仪,对252例可疑胰胆管梗阻性疾病及正常人行MRI和MRCP检查,原始图像作三维重建,分析图像资料并作出诊断。结果:MRCP清晰显示胰胆管的解剖结构,对胰胆管梗阻程度和梗阻部位判定的准确率达100%,恶性胰胆管梗阻端表现为突然截断、锥状或鼠尾状狭窄,结合MRI能够明确肿瘤大小和范围。MRI和MRCP诊断恶性梗阻的敏感性95%、特异性98%、准确率96%。结论:MRI和MR-CP作为无创伤性检查,准确率高,胰胆管的解剖结构显示清晰,可作为胰胆管疾病常规的检查方法,且可作为肿瘤可切除性评估标准之一。     

胆囊癌的CT与MRI影像学表现及腹腔转移性淋巴结的分布特征探讨

胆囊癌的发病率较低,最初临床症状缺乏特异性,与慢性胆囊炎的症状无明显区别,但病变发现时往往已是晚期,且胆囊癌极易发生对邻近脏器的侵润和沿淋巴引流途径转移,所以临床治疗效果极差.