MSCT三维重建指导椎弓根螺钉置入的体外应用研究

目的 :探讨多层螺旋CT三维重建对椎弓根螺钉置入的指导价值。方法 :在多层螺旋CT三维图像上 ,测量两具胸椎标本 (T1～T10 )椎弓根的三维定量解剖数据 ,用以指导椎弓根螺钉的置入。置入螺钉后拔出 ,用显影剂填充钉道。CT测量显影钉道的椎弓根水平位角 (PW )、椎弓根宽度 (PH)、椎弓根高度 (TSA)和椎弓根长度 (SSA )值。在实物标本上用量角器和游标卡尺测量实际值。结果 :配对资料两样本均数比较行t检验 ,CT图像与实物标本测量数据之间的差异无统计学意义 (P >0 .0 5 )。多因素设计资料方差分析证实 ,椎弓根显影钉道的TSA、SSA与其中轴的TSA、SSA之间差异无统计学意义 (P >0 .0 5 )。结论 :多层螺旋CT三维重建后测量的各解剖参数充分体现了个体化原则 ,真实可靠 ,对椎弓根螺钉的准确置入有指导意义。     

多层螺旋CT三维重建技术在颅骨修补术中的应用

目的探讨螺旋CT三维容积重建技术在颅骨缺损患者中的使用技巧和计算机个性化设计钛网在临床的应用。方法30例颅骨缺损患者行螺旋CT扫描,数据传至工作站行三维重建,应用计算机辅助设计（CAD）和制造技术（CAM）进行个性化的颅骨缺损修复体的预制,并应用于临床。结果根据CT数据制作的三维模型能精确地显示颅骨缺损区域的结构,修复体嵌合满意,术后无并发症。结论多层螺旋CT三维重建技术在颅骨缺损修复术中具有重要的临床实用价值。     

IMAR对起搏器植入患者胸部CT扫描的应用价值

目的:通过仿真胸部体模对伪影区域内肺结节及肺组织显示效果的分析,评价IMAR算法对心脏起搏器植入患者CT扫描的应用价值。方法:在胸部仿真体模内置入模拟肺结节60个,分别在心脏起搏器放置前后进行胸部CT扫描(常规剂量及低剂量扫描),图像分别采用无IMAR和有IMAR两种方式进行重建。比较肺结节的检出率,测量模拟肺结节CT值与其标称CT值的差值,并比较图像的噪声值、SNR、CNR值,并对主观图像质量评分。结果:低剂量胸部CT扫描时,使用IMRA检出结节数目较多;使用IMAR算法磨玻璃肺结节的测量CT值与标称CT值的差值较小。使用IMAR重建时图像SNR及CNR值均较高。IMAR重建图像质量主观评分高于未使用IMAR。结论:IMAR算法能减轻心脏起搏器金属伪影,提高低剂量胸部CT对伪影区域结节的检出率,提高伪影区域磨玻璃肺结节的显示效果,提高伪影区域图像质量。     

面神经管螺旋CT多平面和曲面重建成像的临床应用

目的 探讨螺旋CT多平面和曲面重建成像对面神经管显示的临床应用。方法 对1具尸体头颅标本、2个颅骨标本及43例患者进行颞骨螺旋高分辨CT扫描，层厚1．0mm、间距0．2mm、螺距为1。然后进行冠状面、矢状面及斜面的多平面重建(MPR)和面神经管全程的曲面重建成像，对尸体标本解剖面神经管，并与其断面图像对比。结果 CT图像所见与标本解剖一致，40侧正常耳的面神经管迷路段、水平段在轴面扫描图像上显示最优，面神经管垂直段在矢状面及斜面重建图像上显示最优，曲面重建能显示面神经管连续的全程。中耳乳突炎25耳中，面神经管水平段及垂直段有破坏者分别为6耳及5耳；先天性外耳道闭锁的16耳中，面神经管异常达10耳；外伤后面瘫的5耳中，3耳见有面神经管骨折。面神经管在螺旋CT多平面和曲面重建图像上的表现与临床手术所见相符。结论 螺旋CT多平面和曲面重建成像技术有利于面神经管的显示及其病变的诊断。     

16层螺旋CT眼眶三维测量方法分析

目的 建立眼眶16层螺旋CT三维测量方法,探讨其准确性和可靠性. 资料与方法 9例正常成人干燥完整头颅眼眶经16层螺旋CT扫描三维重组成像,共进行8条线距测量,并与干颅眼眶直接测量结果进行统计学分析. 结果 16层螺旋CT眼眶三维测量方法能测量不同平面眼眶线距,其与直接测量方法的结果具有良好的一致性. 结论 16层螺旋CT眼眶三维测量准确、可靠,可作为眼眶测量常规方法.     

多层螺旋CT后处理测量肩胛盂径线的实验研究

目的探讨多层螺旋CT(MSCT)后处理测量肩胛盂径线的方法。方法收集成人肩胛骨干标本50个、成人肩关节防腐湿标本50个,用16层螺旋CT扫描仪扫描,行轴位厚层多平面重组(MPR)、薄层多平面重组测量肩胛盂扭转角,进行统计学处理。结果肩胛盂前后最大径厚层MPR测量值(2.45±0.27)cm,干标本薄层MPR测量值(2.44±0.26)cm,湿标本薄层MPR测量值(2.59±0.32)cm;轴位盂窝深度厚层MPR测量值(2.27±0.58)mm,薄层MPR测量值(2.34±0.68)mm;轴位盂窝后松质骨深度厚层MPR测量值(1.90±0.28)cm,薄层MPR测量值(1.92±0.28)cm;轴位盂窝后1 cm松质骨宽度厚层MPR测量值(1.08±0.23)cm,薄层MPR测量值(1.02±0.20)cm;盂上下最大径厚层MPR测量值(3.36±0.30)cm,薄层MPR测量值(3.39±0.28)cm;冠状位盂窝深度干标本厚层MPR测量值(4.35±0.65)mm,湿标本厚层MPR测量值(3.90±0.93)mm,薄层MPR测量值(4.53±0.79)mm;冠状位盂窝后松质骨深度薄层MPR测量值(1.97±0.29)cm;冠状位盂窝后1 cm松质骨宽度干标本薄层MPR测量值(3.67±0.58)cm,湿标本薄层MPR测量值(3.42±0.55)cm。结论多层螺旋CT多平面重组(MPR)测量肩胛盂径线是简单、快捷的方法。     

股骨标本颈干角的非接触式测量

目的:由于干性尸体股骨标本形态不规则,在进行股骨颈干角测量时难度较大。本文旨在为干性尸体股骨标本颈干角的测量提供一种新方法。方法:将19对,即40例干性尸体股骨标本放置于设计有栅格信息的背景图案下,进行非接触式测量。同时将这19对,38例干性尸体股骨标本进行CT扫描,并获得三维图像进行测量。将非接触式测量结果与三维测量的结果进行统计学分析。结果:两种方法对股骨颈干角的测量结果彼此间相关性具有统计学意义。结论:非接触式测量干性尸体股骨标本颈干角的结果准确,方法可靠。     

螺旋CT三维重建在急性外伤性颅内血肿中的临床价值

目的评价螺旋CT三维重建在急性外伤性颅内血肿中的应用价值.资料与方法对104例急性外伤性颅内血肿患者进行螺旋CT扫描,采用表面遮盖成像(SSD)和表面透视成像Integral技术分别行颅骨、血肿、脑表面的三维重建,伪彩色技术处理后相互合并,在血肿三维空间定位和体积测量后进行手术评估.对需手术治疗者,再术前评估,应用血肿三维空间定位及骨切削技术模拟颅骨开瓣手术,制定手术方案,选择最佳手术入路.结果全部病例三维重建后满意地显示出血肿立体解剖关系.23例手术患者预后满意,术中血肿量与术前测量值基本相同.结论螺旋CT三维重建简化观察者的思维过程,可直观、立体、准确地显示血肿空间解剖关系和体积值,具有较高的临床应用价值.     

三维CT重建对经皮椎体后凸成形术的指导价值

目的 探讨三维CT重建对经皮椎体后凸成形术(PKP)的指导价值.方法 准备行经皮椎体后凸成形术的24例患者,术前行病变椎体的三维CT重建.结果 根据三维CT重建结果,11例患者为手术禁忌而放弃行PKP治疗,其他13例患者经测量得到相应数据,为手术者提供了精确的定位.结论 螺旋三维CT重建对PKP有着较高的指导价值.     

冠状动脉支架内腔的可视度:64层螺旋CT与宝石CT的比较

目的评价宝石CT(HDCT)显示冠状动脉支架的能力,并与64层螺旋CT进行比较。方法 52例患者(共放置85个支架)进行64层螺旋CT和HDCT扫描,分别测量支架内CT值和相邻未放置支架节段的CT值,同时测量支架内径,并对两者进行比较。结果在HDCT上,支架内腔的显示率明显高于64层螺旋CT(分别为69.0%和42.9%,P<0.01)。支架内CT值的上升值分别为15.2 HU和54.2 HU(P<0.01)。结论由于空间分辨率的提高以及有效抑制线束硬化伪影,HDCT与64层螺旋CT比较,提高了支架内腔的可视度,能更准确测量支架的内径。     

A study of volumetric visualization and quantitative evaluation of bone trabeculae in helical CT

OBJECTIVES: The aim of this study was to investigate the reliability of quantitative evaluation of bone trabeculae by helical CT. METHODS: Ten specimens of human cadaver mandibular condyles were examined using both micro-CT and helical CT, and volume rendered three-dimensional (3D) images were obtained from the CT data. Micro-CT was used as the reference standard. From the micro-CT data images, bone trabeculae in each condyle were extracted by image processing and their volumes were calculated automatically. From the helical CT data images, the cortical bone was manually removed and bone trabeculae in each condyle were extracted using opacity curve and colour mapping thresholds. The optimal cut-off CT value that resulted in a similar volume of bone trabeculae obtained from helical CT and micro-CT data was investigated. RESULTS: The optimal cut-off CT value to assess the volume of bone trabeculae accurately on 3D images obtained with helical CT data was found to be 200 Hounsfield units. CONCLUSIONS: This study suggests that quantitative evaluation of bone trabeculae using helical CT might be a valid and useful method.     

输尿管病变的螺旋CT评价

目的探讨螺旋CT各种成像方法在评价输尿管病变中的临床应用价值。方法应用螺旋CT对110例经临床和病理证实的输尿管病变做平扫及四期增强扫描，并作多平面重建(MPR)和三维重建，观察螺旋CT各种成像方法显示和诊断病变的能力，并与其他检查技术及手术病理结果进行比较。结果107例患者螺旋CT轴面结合曲面MPR能很好地显示输尿管病变的部位、大小、形态和分布范围及尿路梗阻的情况，曲面MPR更为直观；81例手术患者，输尿管病变在螺旋CT图像上的表现与手术所见有很好的一致性。三维重建可获得类似于X线尿路造影的图像，能立体显示病变的状况。螺旋CT扫描能很好地弥补其他影像学检查的不足。结论螺旋CT扫描范围大，分辨率高，对输尿管病变的显示和诊断有优越性，尤以曲面MPR价值最大，具有很高的临床应用价值。     

Three-dimensional portography using multislice helical CT is clinically useful for management of gastric fundic varices

OBJECTIVE: This study seeks to evaluate three-dimensional (3D) helical CT portography as a tool for examining patients with gastric fundic varices. SUBJECTS AND METHODS: We compared 3D helical CT portography and conventional angiographic portography in 30 consecutive patients with gastric fundic varices. We assessed whether 3D helical CT portography is useful in selecting patients and in evaluating the results of balloon-occluded retrograde transvenous obliteration. RESULTS: Three-dimensional helical CT portography simultaneously depicted second or third branches of the intrahepatic portal vein and provided images of entire portosystemic collaterals. On 3D helical CT portography, gastric fundic varices were seen in 30 patients (100%), left gastric veins in 19 (63%), posterior gastric veins or short gastric veins in 28 (93%), gastrorenal shunts in 27 (90%), paraumbilical veins in three (10%), and inferior phrenic veins in two patients (7%). Findings of 3D helical CT portography and conventional angiographic portography were in close agreement. However, in four patients, posterior gastric veins or short gastric veins were not seen on conventional angiographic portography images of the spleen, but they were clearly revealed on 3D helical CT portography. Treatment was successful in all patients except one. Three-dimensional helical CT portography could easily evaluate therapeutic results. CONCLUSION: Three-dimensional helical CT portography proved so effective that it can be considered a less invasive alternative than conventional angiographic portography in assessing portosystemic collaterals. CT portography is useful in selecting candidates from patients with gastric fundic varices for retrograde transvenous obliteration and also in evaluating therapeutic results.     

Technical application of three-dimensional visualization and measurement for breast cancer using multidetector-row CT scanner

This paper describes an integrated methodology that addresses the operation of 3D imaging and measurement for the diagnosis and surgical operation of breast cancer. The main system for breast CT imaging used a multi-slice CT scanner and 3D-workstation. The clinical sequence was performed in three phases with non-contrast and biphasic contrast-enhanced studies that were performed with multi-slice helical CT scanning. Acquired DICOM images were directly sent to the 3D workstation that implemented our developed functions. Four types of transfer functions (mammary skin, vessel, lymph node, and tumor) were set based on region-of-interest (ROI) measurements. After that, two types of segmentation were prepared with volumetry and measurement of the size of breast cancer. Batch processing for 3D visualization and the measurement of breast tumors was helpful for diagnosis and surgical planning.     

多层螺旋CT颞骨三维成像与解剖学的对照研究

为了验证多层螺旋CT三难成像的测量数据的准确性，选取10％甲醛固定的成人头颅标本12具（24侧），进行颞骨部位的扫描，并应用表面遮盖显示，容积显示技术对颞骨的三维成像，对几处明显的结构进行测量，然后，再解剖测量，对比，结果显示，多层螺旋CT立体图像清晰，各种表面结构清楚，多层螺旋CT成像的测量数据与解剖测量的数据一致，无统计学的差异，研究表明，多层螺旋CT成像测量的数据，可以直接指导临床。     

A whole-body registration-free navigation system for image-guided surgery and interventional radiology

RATIONALE AND OBJECTIVES: To develop and test an image-guided navigation system in which the base of reference is taken from the imaging modality, here, a helical CT scanner. METHODS: An optical digitizer together with a calibration device is used to measure the transformation matrix between the digitizer reference system and a CT reference system. During intervention, it tracks radiological and surgical tools with tool references. A specific software visually integrates the current tool position with the corresponding image information. In vitro accuracy tests were performed. RESULTS: With helical CT, freehand positioning accuracy was 1.9 +/- 1.1 mm (mean +/- SD) in vitro (n = 718). CONCLUSIONS: The navigation system developed by the authors appears to be feasible for radiological interventions as well as for minimally invasive surgery. It is not limited to a certain procedure, can be used in every region of the body, and is functional after imaging. Intraprocedural scans can be integrated immediately.     

Early postoperative CT scanning for juvenile nasopharyngeal angiofibroma: detection of residual disease

BACKGROUND AND PURPOSE: High recurrence rates and early recurrence have been reported for juvenile nasopharyngeal angiofibroma (JNA) involving the skull base. The purpose of this study was to evaluate the diagnostic accuracy of contrast-enhanced CT scanning for the detection of residual disease (RD) in the early postoperative course after surgical excision of JNA. METHODS: We retrospectively reviewed data in 20 male patients (mean age +/- SD, 15.4 +/- 5 years; range, 10-32 years) who underwent enhanced helical CT in the days after apparent complete surgical excision of JNA with initial expansion in the skull base. Four independent, blinded readers evaluated the occurrence of RD. Final diagnoses were rendered on the basis of histologic examination of excised specimens of RD or clinical and radiologic follow-up. The Cohen kappa test was performed to examine interreader agreement. RESULTS: Postoperative contrast-enhanced CT had a sensitivity of 75%, a specificity of 83%, a positive predictive value of 75% and a negative predictive value of 83% for the detection of RD. The prevalence of RD was 40%. The base of pterygoids was the most frequent location of RD. Interreader agreement was high for the detection of putative RD (kappa=0.83). Variabilities in readers' interpretations were encountered for false-positive results and for disease in the foramen lacerum. False-negative results involved the base of pterygoids. Early postoperative CT scanning was well tolerated by all patients. CONCLUSION: Contrast-enhanced helical CT is an accurate tool to evaluate excision of JNA in the days after surgery.     

A technique for multiplanar reformation and three-dimensional analysis of computed tomographic data: application to adult hip disease

A commercially available system which is able to accept input from computed tomographic (CT) or magnetic resonance (MR) scanners was used preoperatively to generate multiplanar reformations (MPR) and three-dimensional (3D) images depicting the osseous morphologic alterations and femoral-acetabular relationships in 25 adult patients with a variety of hip diseases. Polyethylene surface representations of femora and acetabulae were constructed by the 3D-contouring of CT data and were then compared to resected specimens from patients who subsequently underwent total hip arthroplasty. Information provided by this imaging strategy was useful in both selecting and guiding the most appropriate surgical procedure, and the models depicted actual osseous contours with reasonable accuracy. The system employed has distinct advantages over other previously described 3D imaging strategies, which include a menu-driven user-friendly interface, data base access via reference images, 3D sectional analysis, and contour file editing for selective visualization of desired structures.     

Demonstration of aberrant hepatic and gastric arteries with helical CT.

RATIONALE AND OBJECTIVES: To assess the demonstration of aberrant hepatic and gastric arteries with routine axial biphasic helical CT. METHODS: The arterial-phase images of biphasic helical CT were reviewed to evaluate aberrant hepatic and gastric arteries in 166 patients with hepatocellular carcinomas. Biphasic (30 and 70 seconds) helical CT was performed with 10 mm of collimation. The results were compared with angiography performed within 2 weeks after this CT. RESULTS: Aberrant hepatic arteries were identified by CT in 38 patients and by angiography in 43 patients (38/43, 88%). Aberrant left gastric arteries were identified in three patients by angiography and by CT (3/3). Careful observation of the fissure for the ligamentum venosum and portacaval space was useful for the detection of these arteries. CONCLUSIONS: Aberrant hepatic and gastric arteries were well demonstrated with routine axial biphasic helical CT. This may be useful for the surgical and transcatheter management of hepatic tumors.     

CT assessment of tumour response to treatment: comparison of linear, cross-sectional and volumetric measures of tumour size

Changes in cross-sectional area are currently used to assess tumour response to treatment. The aims of this study were to validate a helical CT technique for volume determination using a series of phantoms and to compare tumour responses indicated by one-, two- and three-dimensional measures of tumour size change in patients treated for germ cell cancer or lymphoma. All studies were performed on an IGE HiSpeed Advantage helical CT scanner with an Advantage Windows workstation. Phantom volumes were calculated using volume reconstruction software and compared with reference volumes determined by water displacement. 20 lymph node masses were studied on serial CT scans in 16 patients treated with chemotherapy for germ cell cancer or lymphoma. For each lesion the maximum diameter, maximum cross-sectional area and volume were determined before and after treatment. Tumour response was assessed using the standard World Health Organisation criteria (i.e. changes in cross-sectional area) and the newly proposed unidimensional response evaluation criteria in solid tumour (RECIST). The CT volume measurement error was 1.0-5.1% for regularly shaped phantoms larger than 35 cm3. In the assessment of treatment response there was 90% agreement between one-dimensional (1D) and two-dimensional (2D) measurements and 100% agreement between 2D and three-dimensional (3D) measurements. CT volume measurements are accurate and reproducible, particularly for larger structures. Assessment of tumour response using 1D, 2D and 3D measures had limited influence on the classification of treatment response. However, the impact of CT assessment of tumour response using 1D, 2D and 3D measurements on clinical decisions and patient outcome remains to be determined.