Noninvasive gadolinium-enhanced three dimensional computed tomography coronary angiography

RATIONALE AND OBJECTIVES: Although the use of gadolinium (Gd)-based contrast agents for angiographic studies of abdominal aorta, renal vasculature, and digital subtraction angiography has been reported, no studies have shown their diagnostic efficacy and image quality in coronary computed tomography angiography (CTA). The aim of this study is to evaluate the image quality of Gd-based contrast agents during coronary CTA. MATERIALS AND METHODS: A phantom study was done to evaluate the attenuation of serial dilutions of Gd and iodinated agents. This study was done on a 64-slice multirow detector CT (MDCT) scanner and e-speed scanner and CT attenuation Hounsfield units (CTHU) were compared. We evaluated 35 consecutive patients who underwent Gd-enhanced CTA. CTHU of aorta was measured at first, mid, and lowest slice levels with and without contrast administration. The image quality was graded on the basis of visualization of the coronary arteries (scale I-III; III demonstrating diagnostic image quality of the distal-most vessels). In a substudy, four patients with borderline renal insufficiency underwent CTA using Gd and iodinated contrast agents admixed in a 50:50 ratio. RESULTS: The phantom study showed that enhancement of various dilutions of Gd and iodine resulted in near identical CTHU with both e-speed and 64-slice scanners (r(2) > or = 0.997). Mean CTHU with contrast at the top slice was 116 HU, at middle slice was 125 HU, and at the lower slice was 93 (111.14 +/- 22). Quality evaluation showed 2 grade III, 9 grade II, and 24 grade I images (average quality of images 1.35). Mean CTHU was 222. CONCLUSION: Gd-enhanced contrast medium provides adequate enhancement of coronary vasculature, allowing for diagnostic evaluation of coronary arteries with new CT systems. Use of newer generations of multirow detector CT scanners should further enhance the quality of images.     

CT在上颌窦鼻腔出血坏死性息肉诊断中的价值

目的　探讨上颌窦鼻腔出血坏死性息肉的CT表现。方法　收集经手术病理证实的 2 9例上颌窦鼻腔出血坏死性息肉 ,术前采用鼻窦轴位和冠状位 ,平扫和 /或增强后CT薄层扫描。结果　病变密度不均匀 ,为低高混杂密度 (2 6/2 9) ,边界清楚 ,增强扫描有轻度强化 ;上颌窦和 /或鼻腔呈膨胀性扩大 ,骨质压迫性吸收破坏以上颌窦内侧壁多见 (13 /2 9) ;多数病例既有骨质破坏 ,又伴有硬化增厚 (15 /2 9)。结论　CT对出血坏死性息肉可作出明确诊断     

肝脏局灶性结节增生的CT多期增强研究

目的探讨CT多期增强扫描对肝脏局灶性结节增生的诊断价值。方法采用螺旋CT对12例肝脏局灶性结节增生进行CT平扫及多期增强扫描,增强扫描动脉期25~30 s,静脉期55~60 s,180 s后延迟扫描。结果CT平扫10例呈低密度或稍低密度,其中5例病灶中心可见不规则更低密度影,2例呈等密度。增强扫描动脉期9例明显强化,其中4例强化均匀,5例强化不均匀,其内平扫不规则更低密度影斑痕强化不明显,3例可见供血动脉,2例病灶边缘有斑块状强化,1例强化不明显。静脉期6例呈稍高密度,4例为等密度,2例为高低混合密度影。延迟期12例均低于肝脏密度呈较低密度。结论CT多期增强扫描对肝脏局灶性结节增生的诊断具有特征性,且较准确,对临床治疗具有指导意义。     

腹盆部巨大淋巴结增生症的CT及MRI表现和不同病理类型能谱CT特征

目的探讨腹盆部巨大淋巴结增生症(Castleman病)的CT和MRI特征性表现,并对不同病理类型进行能谱CT分析。方法 13例患者均行CT平扫+动态增强检查,启用GSI viewer软件,在动脉期及门静脉期图像上综合观察,然后在动脉期图像上测量相关数据,其中10例患者采用3.0TGE Discovery MRI扫描仪行T1WI、T2WI横轴面及T2脂肪抑制轴位平扫,5例行T1WI动态三期增强。结果 CT平扫9例均呈类圆形等密度肿块,轻度分叶,边缘光滑清晰,4例肿块密度不均并伴有斑点状钙化,动态增强9例均见动脉期显著强化、门静脉期、延迟期持续均匀强化,4例伴有钙化的肿块呈不均匀持续强化,2例肿块周围可见子灶。10例行MRI检查,平扫呈等或稍长T2、长T2信号,T2脂肪抑制呈明显高信号,5例增强后病灶呈中度强化,瘤灶内均可见中央条索状及小片状低信号区。本组病例中均为局限型,7例位于腹膜后,3例位于肠系膜区,3例位于盆腔,其中1例合并左侧卵巢纤维瘤。10例病理类型为透明血管型,3例为浆细胞型。综合混合能量图像、单能量图像及碘基图图像三种图像能使病灶显示更清楚,不同病理类型在不同keV下其衰减程度不同,其能谱曲线图表现不同。在碘基图及水基图上可见10例透明血管型碘含量明显增高,而3例浆细胞型碘含量明显低于透明血管型,但含水量稍高于前者。结论腹盆部Castleman病具有一定特征性,CT动态增强及MRI对透明血管型诊断不难,而浆细胞型Castleman病临床表现复杂,影像学表现不典型,术前诊断仍较困难,需结合病理学检查,但能谱CT分析有助于病理分型。     

颈动脉和椎基底动脉16层螺旋CT减影成像的应用价值

目的:探讨颈动脉和椎基底动脉CTA减影技术的临床应用价值。方法:对43例患者行颈动脉和椎基底动脉CTA检查,原始数据在工作站进行减影和三维图像后处理。图像由2名观察者对颈动脉和椎基底动脉的显影情况进行评分,数据应用SPSS11.0进行统计学分析。结果:减影和非减影的颈动脉和椎基底动脉图像的观察评分有显著性差异。CTA减影血管重建后的图像质量优良,在显示颈动脉和椎基底动脉的完整性方面明显优于常规CTA血管重建。减影图像对于显示管壁钙化效果欠佳,需结合平扫和非减影图像进行钙化斑块评估。结论:CTA减影成像技术改善了对颈动脉和椎基底动脉复杂解剖及异常管壁结构的显示,结合非减影图像,可为临床提供更加丰富的诊断信息。     

以脑CT灌注的峰值时间作为脑CTA扫描延时的应用

目的应用CT脑灌注方法准确预测脑动脉环CTA检查延迟时间。方法14例病人均有典型的短暂性脑缺血(TIA)发作史或缺血性脑血管病史,先对其进行CT脑灌注扫描,通过测量大脑前动脉CT值达峰时间与开始扫描时间的差值指导脑动脉环CTA的延迟时间。结果应用此方法指导脑CTA检查,动脉环显示均较满意。结论先行CT脑灌注成像,根据测量值预测脑CTA检查延迟时间是保障CTA检查成功的一种较好的方法。     

肝结核的CT及MRI表现(附2例报告及文献复习)

目的探讨肝结核的CT和MR I表现特点及其鉴别诊断。方法回顾性分析2例经病理证实的肝结核的CT和MR表现特点,并作文献复习。2例肝结核行CT平扫及CT动态增强扫描,1例行MR平扫。结果CT平扫1例呈不均质性低密度,病变内伴有更低密度坏死区,1例接近等密度;CT增强扫描动脉期2例病变均未见明显强化;静脉期及平衡期2例病变轻度强化,其中1例伴有坏死囊变区周边轻微环形强化。1例MR平扫,T1W I呈低信号,T2W I呈等高混杂信号。结论肝结核少见,易误诊,CT及MR I能显示肝结核的一些特征,尤其是动态增强扫描有助于该病的诊断和鉴别诊断。     

多层螺旋CT对胃肠道外间质瘤的诊断价值

目的 探讨胃肠道外间质瘤(EGIST)的CT表现及其诊断价值. 方法 回顾性分析经手术病理证实的19例EGIST的CT资料.结果 肿瘤位于腹膜后8例、肠系膜4例,腹腔4例,原发于肾上腺1例、大网膜1例,网膜及肠系膜1例.良性2例,交界性4例,恶性13例.肿瘤直径4.1～35 cm,类圆形5例,分叶状5例,不规则形9例.平扫密度均匀4例, 增强扫描1例均匀中度强化,1例不均匀强化,2例周边明显环形强化;平扫密度不均匀15例,增强扫描实质部分中度以上强化,囊变坏死部分强化不明显. 结论 EGIST的CT表现具有一定特点, MSCT对EGIST的诊断及鉴别诊断有重要价值.     

多层螺旋CT尿路造影在尿路梗阻性疾病中的临床应用

目的探讨多层螺旋CT尿路造影在泌尿系梗阻性疾病诊断中的应用价值。方法对48例泌尿系统梗阻性疾病者,分别进行多层螺旋CT平扫及多时相期CT增强扫描。对增强后各期图像进行相关处理,以不同的三维重建方式获得CTA、CTU影像。所有病例均经临床及手术证实。结果48例中肾脏及输尿管先天畸形者15例;输尿管阴性结石致肾盂输尿管积水者4例;泌尿系炎症者5例;肾及输尿管、膀胱结核6例;外源性压迫导致肾盂及输尿管积水者8例;泌尿系肿瘤者10例。结论多层螺旋CT泌尿系造影对尿路梗阻性疾病的诊断具有很高的应用价值。     

螺旋CT在肺动脉栓塞诊断中的应用价值

目的　评价螺旋CT对急性肺动脉栓塞的诊断价值。方法　 2 4例临床确诊的肺动脉栓塞病人 ,先行螺旋CT平扫 ,后经肘静脉注入 10 0ml优维显或欧乃派克 ,延迟 15s和 30s行 2次扫描。结果　平扫的间接征象 :肺纹理稀疏 12例 ,肺梗死灶形成 11例 ,肺动脉高压 3例 ,胸膜肥厚 4例 ,胸腔积液 8例。增强后的直接征象 :充盈缺损 (附壁性 32支 ,部分性 30支 ,完全性 92支和中心性即轨道征 15支 )和动脉面细小 14支。结论　螺旋CT扫描速度快 ,图像清晰 ,不遗漏小病灶。螺旋CT肺动脉造影是急性肺动脉栓塞安全、迅速、无创伤的有效诊断方法。     

Castleman disease of the neck: CT and MR imaging findings

Objective

To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Castleman disease of the neck.

Methods

The imaging findings of 21 patients with Castleman disease of the neck were reviewed retrospectively. Of the 21 patients, 16 underwent unenhanced and contrast-enhanced CT scans; 5 underwent unenhanced and contrast-enhanced MRI scans.

Results

The unenhanced CT images showed isolated or multiple well-defined homogenous mild hypodensity lesions in fifteen cases, and a heterogeneous nodule with central areas of mild hypodensity in one case. Calcification was not observed in any of the patients. In five patients, MR T1-weighted images revealed well-defined, homogeneous isointense or mild hyperintense lesions to the muscle; T2-weighted images showed these as intermediate hyperintense. Sixteen cases showed intermediate to marked homogeneous enhancement on contrast-enhanced CT or MR T1-weighted images. Of the other five cases that underwent double-phase CT scans, four showed mild or intermediate heterogeneous enhancement at the arterial phase, and homogeneous intermediate or marked enhancement at the venous phase; the remaining case showed mild and intermediate ring-enhancement with a central non-enhanced area at the arterial and venous phases, respectively.

Conclusion

Castleman disease of the neck can be characterized as solitary or multiple well-defined, mild hypodensity or homogeneous intense lesions on plain CT/MR scans, and demonstrates intermediate and marked enhancement on contrast-enhanced CT/MR scans. On double-phase CT scans, Castleman disease often demonstrates mild enhancement at the arterial phase, and gradually uniform enhancement at venous phase. Double-phase enhanced CT or MRI may help to differentiate Castleman disease from other diseases.     

肝炎性假瘤16层螺旋CT表现分析

目的 研究肝炎性假瘤(IPL)的16层螺旋CT平扫及动态增强扫描表现. 方法 回顾性分析16例肝炎性假瘤的CT平扫及动态增强扫描表现,分别测量病灶及病灶周边肝组织的平扫及增强扫描各时相CT值,并对其进行比较. 结果 16例患者共发现18个病灶,病灶大多位于肝右叶,CT平扫表现为圆形、类圆形或不规则形状低密度影.增强扫描动脉期表现为无或仅为轻度强化,门脉期表现为轻到中度强化,部分病灶表现周边肝组织环形强化,或(及)病灶中心结节状或纤维条索状强化或(及)门静脉分支穿过病灶等特征性改变.统计学提示IPL病灶在动脉期的CT值增加与平扫比较不存在统计学差异(P＞0.05),门脉期的CT值增加与平扫及动脉期比较均存在统计学差异(P＜0.05);而病灶周边区域肝组织在平扫、动脉期及门脉期的CT值两两比较均存在统计学差异(P＜0.05).结论增强CT动态扫描显示IPL病灶整体呈少血供表现,以门脉期及延时期的CT表现最具特征性.     

64层螺旋CT下肢动脉血管减影成像技术的探讨

目的:探讨64层螺旋CT下肢动脉血管造影技术。方法:54例患者进行下肢64层MSCTA血管减影检查,平扫后静脉团注对比剂进行CT血管造影,将增强前后的图像重建成薄层进行减影,从减影中提取动脉进行血管三维显示。结果:54例减影均能显示下肢动脉血管及主要分支。结论:64层螺旋CT血管造影能清晰地显示下肢动脉及其病变,可以成为下肢动脉疾病术前评价和筛选的主要方法。     

胆管细胞型肝癌的CT及DSA表现

目的探讨胆管细胞型肝癌的CT表现及DSA征象,提高胆管细胞型肝癌的诊断水平。方法19例经病理证实的胆管细胞型肝癌的常规CT平扫及双期强化扫描,其中6例同时行延迟扫描,15例行DSA检查。结果CT主要表现:平扫均表现为单发低密度病灶,边界不清;动脉期:所有病灶边缘呈不规则环状轻、中度强化;门脉期:病灶进一步强化呈网格状;延迟期:病灶不均匀向心性增强,略高于正常肝实质。DSA表现:供血动脉轻、中度增粗、僵直,肿瘤染色呈云片状、羽毛状,导管越是超选,肿瘤染色越明显。结论胆管细胞型肝癌的CT及DSA表现具有特征性,对诊断及鉴别诊断具有重要价值。     

CT perfusion image of the lung: value in the detection of pulmonary embolism in a porcine model

RATIONALE AND OBJECTIVES: We assess the value of computed tomography perfusion image (CTPI) obtained by postprocessing the CT data in the diagnosis of pulmonary embolism. METHODS: An experimental pulmonary embolism model was made in 6 pigs by injecting 2 types of emboli into the pulmonary arteries. For each pig, 5 type-A (diameter 3.5 x 8 mm) and 5 type-B (diameter 2.5 x 6 mm) emboli were injected through a catheter with the distal tip located in the inflow tract of the right atrium. After obtaining precontrast and postcontrast CT data during a single breath-hold using a 4-slice multidetector CT, perfusion images were generated by data subtraction. Approximately 150 to 180 mL of contrast material was injected at an injection rate of 6 mL/s to obtain postcontrast CT. Three independent observers twice analyzed CT images for the presence of emboli: once with postcontrast CT scans (CT angiography: CTA) alone and again with both CTA and CTPI. The locations of the emboli in the pulmonary arteries were confirmed by examining the killed porcine lungs. RESULTS: The sensitivity and positive predictive value in the detection of pulmonary emboli with CTA alone were 59% (106/180) and 87% (106/122), respectively. The sensitivity and positive predictive value with both CTA and CTPI were 87% (156/180) and 85% (156/184), respectively. For type-A emboli, the sensitivity with both CTA and CTPI (76/90, 85%) was better than that with CTA alone (63/90, 70%) (P < 0.001). For type-B emboli, the sensitivity with both CTA and CTPI (80/90, 89%) was also better than that of CTA alone (43/90, 48%) (P < 0.001). CONCLUSIONS: CTPI could be obtained using digital subtraction of the CT data. It appeared to be an adjunct in enhancing the diagnostic accuracy of pulmonary embolism, particularly when detecting small pulmonary emboli.     

肝硬化退变结节及小肝细胞癌的CT诊断（附20例报告）

目的探讨CT扫描对肝硬化退变结节（DN）及小肝细胞癌（SHCC）的诊断准确性。方法20例经手术病理证实的SHCC患者起初均经CT平扫与增强扫描，随后又经数字减影血管造影（DSA）检查。结果20例患者共检出SHCC病灶28个，在平扫CT像上，21个病灶呈略低密度，7个病灶接近于等密度而未显示；于增强扫描动脉期，18个病灶呈轻或中度强化，3个病灶呈低密度，其余7个病灶CT平扫呈等密度的6个出现强化。CT检出病灶直径介于0．8—2．0cm。DSA显示27个肿瘤血管丰富，仅1个未见肿瘤染色。分化较好的SHCC与高度变异性DN的血供状况无明显差别。结论CT增强扫描对SHCC有极高的诊断准确性，它可作为临床可疑SHCC患者的常规检查，一经发现动脉供血结节，若患者肝功能好，则应尽早进行手术或介入治疗。     

二氧化碳用于多层螺旋CT诊断肺栓塞的初步实验研究

目的探讨二氧化碳(CO2)作为阴性对比剂在多层螺旋CT(MSCT)诊断肺栓塞(PE)中的可行性。材料与方法6只用明胶海绵建立了PE模型后的犬分别用CO2作为阴性对比剂、碘对比剂作为阳性对比剂行MSCT血管造影检查,对所得两组图像进行比较。结果60ml CO2可使肺动脉充分显影,CO2 CT血管成像和碘对比剂CT血管成像都显示了肺动脉内的栓子,栓子在前者图像上比后者更清晰。结论用CO2作为阴性对比剂行MSCT扫描对诊断PE是可行的。     

中枢神经系统血管外皮细胞瘤的CT、MRI表现

目的探讨中枢神经系统血管外皮细胞瘤(hemangiopericytoma,HPC)的CT、MRI影像学特征.方法回顾性分析经手术、病理证实的9例中枢神经系统HPC的CT、MRI影像学特征,结合文献报道总结本病的诊断与鉴别诊断要点.结果9例中颅内7例,椎管内2例.CT平扫4例呈均匀略高密度,3例呈略高、低混杂密度;MRI检查4例呈等T1、等T2信号,3例呈等长T1、等长T2混杂信号.CT、MRI增强后所有病灶均呈明显强化.结论CT、MRI可对中枢神经系统HPC做出可靠诊断.     

64层螺旋CT数字减影术对头颈部动脉成像应用研究

目的:探讨64层螺旋CT数字减影技术对头颈部动脉成像的优势。方法:对25例怀疑头颈部血管病变患者行64层螺旋CT血管减影成像检查,用特殊头部固定装置固定头颅,先行平扫,然后以相同的扫描参数行增强扫描,将增强前后图像送至工作站进行减影,利用inspace从减影的图像中提取动脉,进行血管重组,其中15例同时行常规CTA检查,8例行DSA检查,比较减影CTA与常规CTA的成像速度、图像质量,并与DSA成像比较。结果:25例均能显示颈总动脉、颈内动脉、椎动脉及主要分支,其中17例颈椎及颅底骨质完全减去,血管显示良好,8例因检查时头部轻微动或做吞咽动作而造成部分颈椎骨及颅底骨未完全减去,但动脉仍能显示,减影CTA平均成像时间4.3min,常规CTA平均成像时间24.3min,2种成像技术比较,颈部动脉图像质量无明显差别,减影CTA对颅内动脉主干及更多分支的显示优于常规CTA,减影CTA与8例DSA比较图像完全相同。结论:64层螺旋CT血管减影技术省时省力、便捷灵活、图像质量好,值得在临床推广。     

64排VCT扫描结合多种后处理技术在胃癌的诊断价值

目的 评价64排vCT扫描结合多种后处理技术在胃癌诊断中的临床应用价值.方法 回顾性分析经病理证实的41例胃癌,均行64排VCT胃充气扫描及四期增强扫描,将所得容积数据传至工作站,行表面遮盖显示(SSD),透明胃(Raysum),仿真内窥镜(CTVE),多平面重建(MPR),曲面重建(CPR),动脉血管重建(CTA),所得结果与胃镜和/或手术病理对比.结果 41例胃癌,轴位图像结合多种后处理技术,对胃癌诊断的准确率为97.56%(40/41),对38例进展期胃癌大体分型准确率为100%(38/38).轴位图像结合CPR及MPR能客观地反映出胃壁病变的部位、形态及大小,确定病变的侵犯程度、胃周脏器的侵犯程度、肿大淋巴结的检出及远处脏器转移情况.SSD、Raysum及CTVE能显示本病的部位、立体形态、大小及范围.CTA均能重建出胃癌的供血动脉.结论 64排VCT扫描与多种后处理技术相结合,能对胃癌进行综合评估,具有较高的临床应用价值.