Multiple Plane Reconstruction Research Articles

Impact of hernia volume on pulmonary complications following complex hernia repair

BackgroundDespite a multitude of evidence-based prediction models and risk factors for postoperative complications after ventral hernia repair, estimating a patient's risk of postoperative complications after ventral hernia repair remains challenging. In an attempt to improve the preoperative assessment of complex hernia patients, some studies have examined pulmonary changes after hernia repair hypothesizing that large hernias lead to pulmonary changes and increased pulmonary complication rates. Some studies have described a correlation between hernia volume and pulmonary changes, although none provided compelling evidence to identify hernia volume as a risk factor for pulmonary complications. This study evaluates the relationship between hernia volume and postoperative pulmonary complications using computed tomography (CT)-based volume measurements. Materials and methodsAnalysis of a prospectively maintained database of consecutive complex hernia patients from 2011 to 2014 undergoing endoscopic (ECST) or open component separation technique (CST) for a hernia defect with a minimum width of 6 cm and visual protrusion of the hernia sac ventral of the rectus abdominis muscles in supine position was performed. Hernia volume was calculated using multiple plane reconstruction of a standard abdominal CT-scan. Noted endpoints were pulmonary complications. ResultsThirty-five patients underwent ECST (n = 20) or CST (n = 15) with a median defect volume of 474 cm3 (range, 114-2086 cm3). Observed complications were pneumonia (n = 4), pulmonary infiltrate (n = 3), aspiration pneumonia (n = 2), and acute respiratory distress syndrome (n = 1). Univariate and multivariate analyses showed that pulmonary complications were associated with “hernia volume” (P = 0.045; 95% CI: 1.008-1.910). ConclusionsHernia volume is a promising risk factor for postoperative pulmonary complications and can be calculated using a standard abdominal CT-scan.

Multislice computed tomography-based prediction of the implantation plane in transcatheter aortic valve implantation: determination of the line of perpendicularity and the implanter's views.

We demonstrate a multislice computed tomography (MSCT)-based method to calculate the prediction of the so-called 'line of perpendicularity' (LOP) and the 'implanter's views' (IVs) for transcatheter aortic valve implantation (TAVI) procedures. The LOP represents all possible angiographic angulations that result in an orthogonal view to the aortic annulus plane. The IVs allow visual confirmation of correct implantation planes, and are crucial for the commissural aligned implantation of second-generation TAVI prostheses. The LOP and IVs of 335 concomitant patients were prospectively analysed using multiple plane reconstruction (MPR) of the patient's MSCT scans. Exclusion criteria were bicuspid valves (n = 18) and valve-in-valve TAVI (n = 15). In the MPRs, the aortic cusps' lowest points were marked. With the marker's three-dimensional coordinates, the graph of the LOP with the IVs was calculated and plotted using vector mathematics. In the last 244 cases, the IV with the right coronary cusp in front was chosen for the first aortic root angiogram of the TAVI procedure. The finally used angulation was confirmed by aortic angiogram prior to the valve implantation. Solid angle differences that show the combined left anterior oblique/right anterior oblique and cranio/caudal movement of the C-arm allow quantification of corrections as well as demonstrate interindividual variations. There is a broad interindividual variation of the aortic valve's topology with solid angle variations of up to 74°. The shape of the LOPs is extremely varying, especially regarding the slope of the curve that indicates differences in valve orientations. Among the 244 patients for whom we used the prediction for the procedure, the first angiogram was considered perfect for implantation without further corrections in 97% (n = 237) of them. In case of the 7 patients with subsequent corrections, the mean solid angle between the prediction and the final angiogram prior to implantation was 6.2° (±5°); the largest correction was 14°. Prediction of the implantation plane by analysing the patient's MSCT is highly reliable in achieving an adequate view of the aortic annulus in TAVI. The analysis of LOPs showed the large interindividual differences that permit using a standard implantation plane. Therefore, we strongly recommend determining the LOP and IVs during the patient's screening process in each single TAVI case.

3D-echo in preoperative assessment of aortic cusps effective height.

Effective height, which represents the height difference between the central free margins and the aortic insertion lines can be easily determined by 2-D echocardiography and allows for identification of prolapse in the native cusps and assessment of prolapse correction after valve repair. Nonetheless, it allows to see only two of three aortic valve (AV) coaptation planes and this may lead to misunderstanding of the underlying pathophysiological mechanism for aortic regurgitation and hence in unsuccessful repair. In contrast, 3D transoesophageal echocardiography and multiple plane reconstruction lets visualize all the three coaptation planes between the AV cusps and it represents an invaluable tool in the assessment of aortic valve geometry. It is highly recommendable before AV repair to accurately study the complex three dimensional cusps anatomy and their geometric interrelation with aortic root.

Image and hemodynamical features of pulmonary artery branches in COPD with pulmonary artery hypertension

To investigate the imaging and hemodynamical features of pulmonary artery branches in chronic obstructive pulmonary disease (COPD) with pulmonary artery hypertension (PAH). CT pulmonary angiography (CTPA) with ECG-gating was performed in 13 patients with clinical diagnosed COPD and 25 normal subjects. The thin-slice multiple plane reconstruction in systole and diastole phase was conducted, which in turn was used to generate the InSpace reconstructed images with reference frame of the main pulmonary artery and the first two grades branches, the contour of the branches was depicted. On the base of coordinates, the GAMBIT was used to generate nodes and furthermore meshes, then the software Fluent was used for numerical calculation and flow simulation. The velocity and pressure changes in the main pulmonary artery and the first two grades branches during different periods of cardiac cycle were observed in both groups. CTPA showed that the diameter of the main pulmonary before bifurcate and proximal of the first two branches was larger in systole period than that in diastole period. The diameter of the second segmental artery of right upper lobe was larger during diastole period. The length of the main pulmonary and the first two branches showed no significant difference in both diastole and systole periods. There was no significant difference in length of pulmonary arteries between COPD and normal groups. The main pulmonary to distal right pulmonary artery appeared larger in diastole period. Compared with normal, in COPD group several arteries increased in diameter including proximal and distal of the proximal right pulmonary artery and the proximal right pulmonary artery during systole and diastole periods. In systole period only the diameter of the main pulmonary before bifurcate got larger and the back basic segmental artery of both lower lobe show smaller than normal. The flow condition analysis in COPD and normal groups suggested higher pressure in pulmonary arteries during systole period than that in diastole period, both groups showed high pressure area below the branching point. In COPD patients the right lower lobe artery endured the most significant pressure fall during the two periods and high pressure distributed larger area than normal. Flow velocity in main branch was faster than lower grade branches and that in systole period was faster than that in diastole period. The trend of diffusion of high pressure area was more prominent in diastole period than normal and the influence more prominent. The distal part of right pulmonary artery to lower lobe artery may be affected earlier when the pulmonary pressure increased. It is feasible to study the changes of flow condition in pulmonary artery branches though the combination of CTPA image and relevant software.

Imaging liver transplantation candidates using gadolinium enhanced MDCT angiography

Aim: To report our experience with gadolinium enhanced computed tomography angiography (Gd-CTA) for end-stage liver disease patients who are candidates for liver transplantation as an alternative to iodinated contrast enhanced CTA and gadolinium enhanced magnetic resonance (MR) angiography. Materials and methods: Seventeen patients with end-stage liver disease were evaluated with Gd-CTA. The patients were 10 men (58.8%) and 7 women (41.1%) (age range: 37-59 years). Multidetector CT (MDCT) was performed using 16-detector-row CT scanners. 3D images of the celiac artery, superior mesenteric artery, portal vein, and inferior vena cava (IVC) were obtained for thorough assessment using multiple plane reconstruction and maximum-intensity projection. Adequate images were defined by complete opacification of the celiac, superior mesenteric, hepatic propria, bilateral hepatic arteries, main portal vein and bilateral intrahepatic portal branches, and IVC. Results: All 17 Gd-CTAs were rated as diagnostic. Adequate CT arteriography (celiac, common hepatic, hepatic propia, and bilateral hepatic artery) and portography were obtained in all the patients. Engorged gastric and coronary varices were detected in 5 patients (29.4%). Severe splenorenal shunt was found in 2 patients (11.7%). Thrombus of the portal vein was observed in 3 patients (17.6%). The radiological findings and operational findings were not discordant in any of the operated patients. Conclusion: The degree of enhancement and image quality achieved using these gadolinium-enhanced MDCT angiographies appear adequate for angiographic evaluation of liver transplantation. Therefore, the use of 3D Gd-CTA in selected cases and settings can be advantageous in the pretransplantation evaluation.

Flow simulation of normal pulmonary artery branches based on multiple detectors computed tomography

To simulate the flow condition in the main pulmonary artery and the branches of left and right pulmonary arteries by combining the images from CT pulmonary angiography (CTPA) by multiple detectors computed tomography (MDCT) and the flow condition data from ultrasonic cardiography. The normal enhanced chest CTPA images with ECG-gating from 25 persons undergoing physical examination, 21 males and 4 females, aged 39, underwent thin-slice multiple plane reconstruction in diastolic and systolic periods respectively. These images were stored in the InSpace software. On the base of coordinates GAMBIT software was used to generate the nodes and meshes. FLUENT software was used to simulate the blood flow speed and pressure field distribution. The pressure levels of the main pulmonary artery and the branches of left and right pulmonary arteries were higher during the systolic period. The blood flow velocity was faster during the systolic period too. The right lower lobe artery endured the most significant pressure during both systolic and diastolic periods. However, there were not significant differences in pressure and blood flow velocity between the systolic and diastolic periods in the segmental arteries. The right lower lobe artery is the first part to be affected when the pulmonary pressure rises. It is feasible to study the changes of the flow condition in the branches of pulmonary artery through combining CTPA images and relevant softwares.

The value of spiral CT in diagnosis of intestine entocele

Objective To elevate the usefulness of spiral CT in diagnosis of intestinal entocele. Methods The CT findings of 11 cases of intestinal entocele proved by operation were reviewed.The main reconstruction techniques were MPR(multiple plane reconstruction)and STS-MIP(slip thin slab maximal intensity projection).Results Eleven cases of intestinal entoceles were all diagnosed accurately before operation.The main sign were left paraduodenal hernia,demonstrated as a saclike mass between stomach and pancreas,clustering,displacing or crowding and elongating of small-bowel loops,engorgement and crowding of the mesenteric vessels with frequent right displacement of the main mesenteric trunk,other bowel displacing.Orificium hernialis were seen with bowel obstruction.When intestinal entocele accompanying torsion,whirlpoolof intestine and mesentery vessels were seen.Conclusion Spiral CT and MPR,STS- MIP techniques have important clinical value to diagnose the intestinal torsion.

Features and clinic values of normal lumbar nerve root anatomy with CT on multiple plane reconstruction techniques at the same slice

目的 探讨腰神经根(LNR)16层螺旋CT多平面重组同层显示的解剖学特征及临床价值.方法 选55例腰椎正常者和23例经手术病理证实的LNR病变者(腰椎椎间盘突出症8例、椎管狭窄症5例、恶性肿瘤4例、创伤5例及结核1例).使用美国GE公司生产的Light Speed 16层螺旋CT扫描,在工作站(ADW 4.1)上利用UNIX操作系统进行LNR多平面重组,选取LNR走行清晰的同层显示层面,观察其解剖学特征.对病变者重点分析其异常表现.结果 在斜冠状面上双侧LNR可对称显示:55例(100%)L1～5的LNR均可分别单节段显示;55例(100%)L1～2或L2～3,以及L3～4的LNR均可同时显示2个节段;49例(88%)L1～3、46例(84%)L2～4、20例(36%)L3～5可同时显示3个节段;15例(27%)L1～4的LNR同时显示4个节段;8例(15%)同时显示5个节段LNR.每条LNR均能显示走行的起止点、方向、大小、形态、张力状态及毗邻关系.除斜冠状面外LNR均不能对称显示,但显示的长度相对增加而数目减少,单根重组时LNR均显示的最长.LNR异常主要表现受压23例,同时伴粘连20例,移位14例,萎缩13例,增粗9例.结论 16层螺旋CT的多平面重组同层显示技术是整体显示LNR解剖学特征极为理想的方法,它对LNR病变的影像学诊断奠定了基础.LNR走行同层显示及路标的新概念,可能为其进一步影像学研究奠定基础。

On the way to isotopic spatial resolution: technical principles and applications of 16-slice CT

The broad introduction of multi-slice CT by all major vendors in 1998 was a milestone with regard to extended volume coverage, improved axial resolution and better utilization of the tube output. New clinical applications such as CT-examinations of the heart and the coronary arteries became possible. Despite all promising advances, some limitations remain for 4-slice CT systems. They come close to isotropic resolution, but do not fully reach it in routine clinical applications. Cardiac CT-examinations require careful patient selection. The new generation of multi-slice CT-systems offer simultaneous acquisition of up to 16 sub-millimeter slices and improved temporal resolution for cardiac examinations by means of reduced gantry rotation time (0.4 s). In this overview article we present the basic technical principles and potential applications of 16-slice technology for the example of a 16-slice CT-system (SOMATOM Sensation 16, Siemens AG, Forchheim). We discuss detector design and dose efficiency as well as spiral scan- and reconstruction techniques. At comparable slice thickness, 16-slice CT-systems have a better dose efficiency than 4-slice CT-systems. The cone-beam geometry of the measurement rays requires new reconstruction approaches, an example is the adaptive multiple plane reconstruction, AMPR. First clinical experience indicates that sub-millimeter slice width in combination with reduced gantry rotation-time improves the clinical stability of cardiac examinations and expands the spectrum of patients accessible to cardiac CT. 16-slice CT-systems have the potential to cover even large scan ranges with sub-millimeter slices at considerably reduced examination times, thus approaching the goal of routine isotropic imaging.

Segmented multiple plane reconstruction: a novel approximate reconstruction scheme for multi-slice spiral CT

A new reconstruction scheme for multi-row spiral CT is described and results are presented. The spiral path is decomposed into small, overlapping segments which are used for a separate convolution and backprojection yielding a stack of segment images which contain only projection data of a partial scan (typically in the range of 20°). These segment image stacks are, in a second step, reformatted to the requested image planes. In a third step, the reformatted segment images are added to obtain full images. The main benefit of the proposed algorithm is superior image quality. A 64-row dataset with a cone angle of 6.4° and a table feed of 80 mm per spiral turn has been reconstructed with excellent image quality. A filter direction for three-dimensional (3D) backprojection algorithms is suggested by investigating the limit where the partial scan size goes to zero.

New technical developments in multislice CT--Part 1: Approaching isotropic resolution with sub-millimeter 16-slice scanning.

The introduction of multislice CT was a breakthrough with regard to increased scan speed, improved axial resolution and better utilization of the tube output. The new generation of multislice CT scanners offering simultaneous acquisition of up to 16 sub-millimeter slices represents an important leap on the way towards true isotropic scanning. We present an evaluation of a state-of-the-art 16-slice CT system (SOMATOM Sensation 16, Siemens AG, Forchheim, Germany). After an introduction to the detector design we discuss dose utilization and finally elaborate on multislice spiral scanning with 16 slices. Due to the increased number of slices dose utilization is improved compared to current 4-slice CT scanners, and sub-millimeter collimation needs no longer be restricted to special applications. For CT systems with 8 or more slices, the cone-beam geometry causes severe artifacts if not corrected for by a so-called cone-correction, which thus becomes mandatory in this case. With the Adaptive Multiple Plane Reconstruction AMPR, cone beam artifacts are effectively suppressed, while the benefits of Adaptive Axial Interpolation are maintained: free selection of the spiral pitch according to the clinical needs of an examination, slice width independent of the pitch, full dose utilization at all pitch values. Clinical practice will have to demonstrate the application spectrum that is opened with the new generation of multislice CT systems.