三维CT图像的运动伪影

目的研究呼吸运动对三维CT成像的影响和运动伪影的规律。方法根据螺旋扫描的基本原理建立运动伪影的数学模型,分析三维图像几何形变;并采用自制体模在CT扫描仪上进行实验验证。结果静止条件下的三维图像细节清楚,失真小;运动条件下的三维图像存在明显变形,程度随螺距和运动周期的增大而减小,初始相位不同图像也有所不同。结论三维CT图像的几何形变取决于目标运动的特点和螺距、层厚等扫描参数。     

Three-dimensional helical CT of pulmonary arteries in infants and children with congenital heart disease.

OBJECTIVE: The purpose of our study was to determine the value of three-dimensional reconstructed helical CT in the assessment of the pulmonary arteries in infants and children with complex congenital heart disease. MATERIALS AND METHODS: Twenty patients were examined with contrast-enhanced helical CT. Three-dimensional reconstructions were performed with multiplanar reformations, maximum intensity projection, and shaded-surface display. Correlation was made with 19 echocardiograms and 14 cineangiocardiograms. All imaging studies were reviewed independently for the following parameters: the caliber of the main and branch pulmonary arteries and their confluence, the presence of stenosis, the number and caliber of aortopulmonary collaterals, and the patency of vascular shunts and conduits. Surgical confirmation, which was used as the reference standard, was available in all patients. RESULTS: Helical CT was as accurate as angiocardiography in revealing stenotic and nonconfluent central pulmonary arteries and in revealing aortopulmonary collaterals (overall CT test parameters: sensitivity, 90%; specificity, 100%; accuracy, 93%).Three-dimensional rendition did not improve the accuracy of CT. The patency of shunts was shown equally well with CT as with angiography, but CT showed thrombosis more directly. Echocardiography was the least accurate technique in revealing pulmonary artery anatomy (accuracy, 65%), primarily because a relatively large number of studies were technically unsatisfactory to assess the study parameters. CONCLUSION: Helical CT angiocardiography with three-dimensional reconstruction is superior to echocardiography for the noninvasive assessment of pulmonary artery anatomy in patients with complex congenital heart disease. Helical CT may be used as a complementary technique and occasionally as a substitute for the diagnostic imaging portion of cardiac catheterization with cineangiocardiography.     

Three-dimensional CT of Eagle's syndrome

This case report presents three-dimensional computed tomography (3D-CT) findings in the diagnosis of Eagle's syndrome that is characterized with an elongated styloid process or a calcified stylohyoid ligament causing craniofacial or cervical pain. We have performed 3D-CT in three patients suspected to have this condition. Coronal images were taken in two patients and axial images in one patient with a spiral CT scanner. 3D-CT images were then produced. The length of the styloid process in the case suspected of right elongated styloid process was 45.6 mm (left styloid process, 37 mm). In the second case suspected of left elongated styloid process, the length of the left styloid process was 41.1 mm (right styloid process, 40.2 mm). In the last case suspected of right elongated styloid process, the length of the right styloid process was 40.6 mm (left styloid process, 38.9 mm). 3D-CT is a valuable diagnostic tool in the diagnosis of Eagle's syndrome because of its ability to facilitate accurate measurement of the length of the styloid process.     

320排CT曲面重组肝脏灌注成像的可行性研究

目的:探讨320排CT全肝灌注成像结合肝脏曲面重组(CPR)技术临床应用的可行性和价值.方法:36例患者(正常肝脏20例,肝细胞癌16例)行CT动态容积扫描,经图像后处理分别获得横轴面和曲面重组肝脏灌注图像.结果:正常肝脏在CPR和横轴面图像上测得的肝动脉灌注(HAP)值分别为(29.3±6.3)和(31.1±5.0)...     

Three-dimensional spiral CT for neurosurgical planning

We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important.     

蝶腭孔的CT三维成像

目的 探讨CT三维成像评价蝶腭孔相关结构的价值.方法 使用Philips Mx8000型多层CT对5个成人头颅标本进行准直1 mm或0.5 mm的容积采集,并将数据输入配套Mxview工作站(SGI O2)进行三维重建处理,包括容积显示(VR)和三维正交多平面重建(MPR).并将图像上测量的数据与标本上实际测量的数据进行配对t检验.同时用相同的技术对12例临床病人进行扫描重建,并与标本CT图像进行比较.结果 蝶腭孔区各结构均能在三维重建图像中直观、清楚地显示,并且在VR所测数据与实际标本上所测数据基本一致.临床病例检查图像与标本图像质量相当.结论 CT容积采集三维重建可以直观、立体地显示蝶腭孔相关结构,准确地测定相关数据,并可应用于临床.     

多层螺旋CT多平面及曲面重建在小儿肠套叠诊断中的应用简

目的：探讨多层螺旋CT（MSCT）后处理重建技术对小儿肠套叠诊断的价值。方法分析47例空气灌肠整复或手术证实肠套叠MSCT表现,所有病例均多平面重建（MPR）、曲面重建（CPR）重组,测量套叠肠管长度及管壁肿胀厚度。结果横轴面显示靶征43例,彗星尾征伴肾形肿块23例,结合MPR显示靶征47例（100%）、彗星尾征伴肾形肿块33例（70.2%）。整复成功36例,失败9例。成功组套叠肠管长（8.20±3.06）cm,厚（0.81±0.29）cm,失败组：长（12.15±0.26）cm,厚（1.47±0.28）cm。2组比较差异有统计学意义（t 长=3.8360,t 厚=6.1456,P值均〈0.01）。结论 MSCT多平面技术能提高套叠特征性征象显示率,套叠肠管长度及管壁厚度的测量,能帮助临床预测整复成功率,正确选择治疗方案。     

Multipath curved planar reformation of the peripheral arterial tree in CT angiography

The study was approved by the institutional review board, and informed consent was obtained. The purpose of the study was to prospectively quantify the angular visibility range, determine the existence of orthogonal viewing pairs, and characterize the conditions that cause artifacts in multipath curved planar reformations (MPCPRs) of the peripheral arterial tree in 10 patients (eight men and two women; mean age, 69 years; range, 54-80 years) with peripheral arterial occlusive disease. Percentage of segments with the maximal possible visibility score of 1 was significantly greater (odds ratio, 1.42; P<.001) for MPCPRs than for maximum intensity projections. One or more orthogonal viewing pairs were identified for all above-knee arterial segments, and artifactual vessel distortion was observed when the vessel axis approached a horizontal course in MPCPRs.     

Advantages of multidetector-row CT with multiplanar reformation in guiding percutaneous lung biopsies

PURPOSE: This study aimed to assess the usefulness of multiplanar reformations (MPR) during multidetector-row computed tomography (MDCT)-guided percutaneous needle biopsy of lung lesions difficult to access with the guidance of the native axial images alone owing to overlying bony structures, large vessels or pleural fissures. MATERIALS AND METHODS: MDCT-guided transthoracic needle biopsy (TNB) was performed on 84 patients (55 men and 29 women; mean age 65 years) with suspected lung neoplasm by using a spiral MDCT scanner with the simultaneous acquisition of six slices per rotation. We determined the site of entry of the 22-gauge Chiba needle on native axial images and coronal or sagittal MPR images. We took care to ensure the shortest needle path without overlying large vessels, main bronchi, pleural fissures or bony structures; access to the lung parenchyma as perpendicular as possible to the pleural plane; and sampling of highly attenuating areas of noncalcified tissue within the lesion. RESULTS: Diagnostic samples were obtained in 96% of cases. In 73 patients, lesions appeared as a solid noncalcified nodule <2 cm; 11 lesions were mass-like. In 22, the biopsy required MPR guidance owing to overlying ribs (18), fissures (2) or hilar-mediastinal location (2). CONCLUSIONS: MDCT MPR images allowed sampling of pulmonary lesions until now considered unreachable with axial MDCT guidance because of overlying bony structures (ribs, sternum and scapulae) or critical location (hilar-mediastinal, proximity to the heart or large vessels). Compared with the conventional procedure, the use of MPR images does not increase the rate of pneumothorax or the procedure time.     

64 Multidetector CT with multiplanar reformation in evaluation of bilateral ovarian masses

Purpose

To evaluate the role of 64 multidetector CT (MDCT) with multiplanar reformation in evaluation of bilateral ovarian masses and to correlate the findings with histopathological results and surgery.

Material and methods

MDCT was performed to 23 patients with sonographically detected bilateral ovarian masses. All scans were performed on a 64 row CT scanner at the oncology center, Mansoura University. The axial and reformatted images were evaluated for lesion characterization and the relationship to adjacent structures. The radiological findings were correlated with operative and pathological findings.

Results

There were 11 bilateral malignant lesions and 9 bilateral similar benign lesions. Three cases showed different benign lesions in both sides.All malignant lesions were read by MDCT as malignant, also all benign lesions were read by MDCT as benign except for one case with endometrioid cyst which was diagnosed as malignant tumor by CT.

Conclusion

64 Multidetector CT with MPR in different planes allows good visualization and characterization of bilateral ovarian masses with greater diagnostic accuracy and improves the detection of peritoneal metastases.     

非增强螺旋CT全尿路曲面重建诊断输尿管结石

目的 :探讨非增强螺旋CT全尿路曲面重建对输尿管结石的诊断价值。方法 :11例患者行全尿路非增强螺旋CT扫描 ,并行冠状及矢状曲面重建。结果 :11例患者冠状及矢状曲面重建像均清楚地显示输尿管全程。其中 10例示结石位于输尿管腔内 ,同时显示结石大小、形态、位置和输尿管梗阻扩张程度及范围 ,1例同时显示合并两肾结石。结论 :非增强螺旋CT全尿路曲面重建可获得良好的输尿管成像 ,结合轴位平扫CT图像 ,在输尿管结石诊断和鉴别诊断方面具有重要的临床价值。     

CT head in children

The advances in computerized technology (CT) technique over the last few decades have greatly modified imaging protocols in children. The range of pathologies that can now be demonstrated has broadened with the advent of newer techniques such as CT perfusion and the ability to perform complex reconstructions. Increasing speed of scanning and reduction in scan time have influenced the need for sedation and general anaesthetic as well as impacting on motion artefact. Additionally, concerns about radiation safety and avoidance of unnecessary radiation have further impacted on the inclusion of CT in the imaging armamentarium. Justification and image optimisation are essential. It is important to familiarize oneself with the appearances of normal variants or age related developmental changes. CT does however remain an appropriate investigation in a number of conditions.     

Medial axis reformation: a new visualization method for CT angiography

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate a new method (medial axis reformation [MAR]) for visualizing three-dimensional vascular data at electron-beam computed tomographic (CT) angiography. MATERIALS AND METHODS: MAR was performed automatically with a personal computer-based workstation. After the region of interest was edited, voxels were divided into groups according to their path lengths. Centroids of groups were connected to form the medial axis. Then, the medial axis was refined with multiscale medial response. Bifurcations were also detected and refined. Finally, curved sections were generated through the branches and laid out onto a single image by using a splitting method. The authors performed MAR during electron-beam CT angiography of coronary arteries, common carotid arteries, and iliac arteries. RESULTS: MAR displayed curved sections of branched vessels on one image, cut through the axis of vessels to show the vessel diameter objectively, and allowed the viewing direction to be altered arbitrarily. CONCLUSION: Results of preliminary applications demonstrate that MAR is a valuable new visualization method for CT angiography.     

心脏移植术后三维CT成像的临床研究

心脏移植是目前治疗终末期心脏病的惟一理想方法,而其中移植心脏血管病变(cardiac allgraft vasculopathy,CAV)是心脏移植术后最难处理的并发症之一[1].因移植心脏处于去神经状态,故患者心肌缺血或心肌梗死相关的心绞痛症状不明显,所以每年均需做血管造影随访或心肌活检等.常规冠状动脉造影(CCA)是诊断冠状动脉病变的金指标,但属于有创检查、价格昂贵,反复检查不易为患者接受,而且已被证明对CAV的敏感性低[2].笔者应用64层MSCT对11例心脏移植术后的患者进行检查,探讨其对移植心脏病变的显示及临床诊断价值.     

Three-dimensional volume-rendered helical CT before laparoscopic adrenalectomy

Use of three-dimensional (3D) volume-rendered helical computed tomography (CT) in surgical planning before laparoscopic adrenalectomy was evaluated in a retrospective study. In 35 consecutive patients before laparoscopic adrenalectomy, 3D volume-rendered CT scans were created from helical CT scans. Videotapes that showed anterior, lateral, posterior, and posterocephalic approaches were assessed retrospectively. The relationship (not contacting, abutting, displacing, or invading) of adrenal masses to adjacent organs (diaphragm, liver, spleen, kidneys, stomach, pancreas, and vessels) was recorded and compared with findings in surgery reports. When such findings were available, they corresponded to those in the videotape. Three-dimensional volume-rendered CT successfully displayed the relationship of adrenal masses to adjacent anatomic structures and organs before laparoscopic adrenalectomy.     

多层螺旋CT曲面重建技术在胆总管扩张诊断中的应用

目的:研究胆总管扩张螺旋CT曲面重建技术(CPR)的操作方法、临床应用价值及其局限性。方法:收集20例胆总管扩张患者,将其1～3mm薄层扫描轴位源像(ASI)传到工作站后处理,行扩张胆总管曲面重建成像,作任意曲面显示所要观察的扩张胆总管。经手术病理及随访证实,评估CPR对胆总管扩张病因的定位与定性价值。结果:CPR对扩张胆总管的成像率达100%,均能显示完整的扩张胆总管及梗阻部位,定位准确率达100%,定性准确率达90%。结论:CPR能将不在同一平面的扩张胆总管显示于一个平面上,更好地显示扩张胆总管的连续性,可直观地显示胆总管扩张程度、部位及梗阻端形态,对诊断及鉴别诊断有重要价值。     

肩关节斜冠位多平面重组的应用研究

目的：探讨多平面重组（mulfiplanar reformation,MPR）技术对肩关节进行斜冠位成像的方法及其应用价值。方法：搜集经16层螺旋CT常规肩关节容积扫描及薄层重建20例（40侧）,均应用多向调整MPR（AMPR）、在旋转容积再现（VR）图像的基础上行MPR（旋转式MPR,RMPR）及常规MPR（CMPR）技术对重建图像进行斜冠位重组,最后由2名CT诊断医师对所有重组图像进行观察和分析。结果：40侧肩关节中,三种MPR技术均获得了斜冠位图像。在显示肩关节图像质量方面,AMPR与RMPR模式优于CMPR模式（UAMPR：CMPR=-6．648,URMPR：CMPR=-6．388,P值均=0．000）,AMPR与RM-PR模式无差异性（U=-0．338,P=0．735）;在肩关节成像的简易程度方面,AMPR模式优于RMPR模式（P=0．000）。结论：AMPR、ILMPR技术获得的斜冠位图像均能直观显示肩关节,优于CMPR技术,RMPR技术较AMPR技术简便,在评价肩关节疾患方面斜冠位图像较常规冠状位图像更具优势和应用价值。