Volume Rendering Technique Reconstruction Research Articles

Realistic three-dimensional imaging of injuries in forensic medicine - Survey-based method comparison of CRT and VRT

ObjectiveA comparison between Cinematic Rendering Technique (CRT) and Volume Rendering Technique (VRT) in cases with postmortem CT-angiography (PMCTA) was carried out. MethodsFor different injuries seen in PMCTA, a VRT and a CRT image of exactly the same pathological section was generated. Two questionnaires were created, one with CRT and one with VRT reconstructions, with the same questions per 3D-image. The questionnaires were sent to forensic pathologists, lawyers and police officers. In total eleven different injuries had to be analyzed. ResultsIn total 109 questionnaires were answered fully. Of these returnees, 36 stated that they were forensic pathologists. Seventy-three people were assigned to the group of medical laypersons, in the study this group consists mainly of police officers, judges and lawyers. Between the two software programs CRT and VRT that were compared, no significant difference could be identified in any of the participating groups with regard to the assessment of the life-threatening nature of the injury images shown. When asked about the comprehensibility of pathology, there was a significant difference in favour of CRT. This advantage was apparent to named medical laypersons and to forensic pathologists. ConclusionsThe study showed a positive trend that CRT may be more understandable than VRT. Not only the medical laypersons, but also the forensic physicians found CRT to be beneficial.

Is CT-based cinematic rendering superior to volume rendering technique in the preoperative evaluation of multifragmentary intraarticular lower extremity fractures?

PurposeCinematic rendering (CR), a recently launched, FDA-approved rendering technique converts CT image datasets into nearly photorealistic 3D reconstructions by using a unique lighting model. The purpose of this study was to compare CR to volume rendering technique (VRT) images in the preoperative visualization of multifragmentary intraarticular lower extremity fractures. MethodIn this retrospective study, CT datasets of 41 consecutive patients (female: n = 13; male: n = 28; mean age: 52.3 ± 17.9y) with multifragmentary intraarticular lower extremity fractures (calcaneus: n = 16; tibial pilon: n = 19; acetabulum: n = 6) were included. All datasets were acquired using a 128-row dual-source CT. A dedicated workstation was used to reconstruct CR and VRT images which were reviewed independently by two experienced board-certified traumatologists trained in special trauma surgery. Image quality, anatomical accuracy and fracture visualization were assessed on a 6-point-Likert-scale (1 = non-diagnostic; 6=excellent). The regular CT image reconstructions served as reverence standard. For each score, median values between both readers were calculated. Scores of both reconstruction methods were compared using a Wilcoxon-Ranksum test with p < 0.05 indicating statistical significance. Inter-reader agreement was calculated using Spearman’s rank correlation coefficient. ResultsCompared to VRT, CR demonstrated a higher image quality (VRT:2.5; CR:6.0; p < 0.001), a higher anatomical accuracy (VRT:3.5; CR:5.5; p < 0.001) and provided a more detailed visualization of the fracture (VRT:2.5; CR:6.0; p < 0.001). An additional benefit of CR reconstructions compared to VRT reconstructions was reported by both readers in 65.9 % (27/41) of all patients. ConclusionsCR reconstructions are superior to VRT due to higher image quality and higher anatomical accuracy. Traumatologists find CR reconstructions to improve visualization of lower extremity fractures which should thus be used for fracture demonstration during interdisciplinary conferences.

Investigation of an Egyptian Mummy board by Using Clinical Multi-slice Computed Tomography

ABSTRACTA modern approach to the diagnosis of artistic heritage makes use of non-destructive techniques which avoid damage to artworks or signs of interaction with the analytical technique used. For this reason, today, the employment of X-rays to study artistic heritage is quite widespread. Computed tomography (CT) Imaging was first used as specialized medical diagnostic tool in the early 1970s. Today, CT scanners have become more common, and non-destructive three-dimensional imaging has found an increasing number of uses in different areas such as materials research, geology, archaeology, and museum conservation. In this work, a new generation of clinical CT (based on the Dual Energy and multi-slice acquisition principle) is used to investigate an Egyptian wooden mummy board with a total acquisition time of 93.23 seconds and a voxel size of 0.078 × 0.078 × 1.5 mm. The use of two distinct techniques of image post-processing, the two-dimensional multi-planar reconstruction (MPR) and the three-dimensional volume rendering technique (VRT) allowed us to: evaluate the state of conservation of the mummy board, determine how the wooden object was implemented, recognize a nineteenth-century intervention of consolidation, and advance the hypothesis that the wooden planks were reused. In particular, we highlight the use of the cardiovascular and pulmonary filter with VRT reconstruction, which allows a virtual elimination of different parts of the mummy board to investigate those areas otherwise accessible only by removing parts of the board and thus damaging the work.

Angiographic C-arm CT visualization of the Woven EndoBridge Cerebral Aneurysm Embolization Device (WEB): First Experience in an Animal Aneurysm Model

Improvements in the imaging capabilities of angiographic C-arm computed tomography (CT) using flat detector angiographic (FD-CT) systems now provide a means for the in vivo visualization of devices used for the treatment of intracranial aneurysms. One such device, the WEB embolization device, is made of a braided mesh of nitinol wires, the size of which are near to the limits of visualization using conventional x-ray fluoroscopy. Our hypothesis was that the imaging of these implants C-arm CT would provide useful information regarding their positioning and deployment. In five New Zealand white rabbits elastase induced aneurysms were created and subsequently treated using a WEB. Imaging was performed using digital subtraction angiography (DSA), X-ray imaging and two different Angiographic C-arm CT protocols. The images were evaluated by two neuroradiologists using an evaluation scale. The mesh of the WEB was barely visible on the DSA or x-ray fluoroscopy images. Volume rendering technique (VRT) reconstruction and multiplanar reconstruction (MPR) of images done using the C-arm CT protocols clearly delineated the shape and structure of the device. Contrast-enhanced MPR and VRT reconstructions allowed assessment of the status of blood flow in the aneurysms. Beam hardening artifacts caused by platinum markers on the WEB were present. In vivo C-arm CT imaging of the WEB is feasible and allows precise determination of the position and deployment status of the device. On contrast-enhanced images the occlusion status of aneurysms and the positioning of the WEB in relationship to the parent artery can be evaluated. C-arm-CT may serve as a minimal-invasive follow-up imaging modality.

Comparison study of four imaging modalities in diagnosis of primary synovial osteochondromatosis

Objective To compare the diagnostic value of X-ray, CT, MRI, and ultrasound in primary synovial osteochondromatosis ( PSO ). Methods The imaging data of X-ray, CT, MRI, and ultrasound of 42 patients with 44 knees with PSO proved by surgery and pathology were retrospectively collected and analyzed. Results The Plain X-ray demonstrated 197 calcific nodules in 28 joints, 96 ossific nodules in 24 joints, and 5 mixed type nodules in 3 joints. Compared with the data of surgery and pathology,36 joints (81.8 ％, 36/44) were diagnosed correctly by X-ray. The CT showed 8 big cartilaginous nodules in 5 joints, 255 calcific nodules in 30 joints, 146 ossific nodules in 28 joints, and 16 mixed type nodules in 7 joints. Twenty-four knees underwent volume rendering technique reconstruction which displayed the quantity, size, shape, and position of non-cartilaginous nodules clearly. Compared with the data of surgery and pathology, 40 joints (90. 9％ , 40/44)were diagnosed correctly by CT. The MRI demonstrated 8 big cartilaginous nodules in 5 joints, 70 small cartilaginous nodules in 4 joints, 248 calcific nodules in 29 joints,146 ossific nodules in 28 joints, and 16 mixed type nodules in 7 joints. All nodules displayed low signal in DWI and there was no enhancement. Compared with the data of surgery and pathology, 43 joints (97.7％,43/44) were diagnosed correctly by MRI. The ultrasound showed 8 big cartilaginous nodules in 5 joints,70 small cartilaginous nodules in 4 joints, 232 calcific nodules in 30 joints, 142 ossific nodules in 28 joints,and 16 mixed type nodules in 7 joints. Compared with the data of surgery and pathology, 43 joints (97. 7％,43/44) were diagnosed correctly by ultrasound. Conclusions The less common manifestations of the PSO require multimodality imaging to make the diagnosis. Multimodalities (X-ray,CT, MRI and ultrasound) are particularly useful in fully characterising PSO and to allow for appropriate clinical planning. Key words: Chondromatosis synovial; Diagnostic imaging

Multislice Spiral Computed Tomography Imaging in Congenital Inner Ear Malformations

The purpose of this study is to evaluate the usefulness of multislice spiral computed tomography (CT) in the diagnosis of congenital inner ear malformations. Forty-four patients with sensorineural hearing loss were examined on a Somatom Sensation 16 (Siemens) CT scanner. The 3-dimensional reconstructions and multiplanar reformation (MPR) were performed using the volume-rendering technique (VRT) on the workstation. Of the 44 patients examined for this study, 25 patients were found to be normal and 19 patients (36 ears) were diagnosed with congenital inner ear malformations. Of the malformations, the axial, MPR, and VRT images can all display the site and degree in 33 of the ears. Volume-rendering technique images were superior to the axial images in displaying the malformations in 3 ears with small lateral semicircular canal malformations. The common malformations were Michel deformity (1 ear), common cavity deformity (3 ears), incomplete partition I (3 ears), incomplete partition II (Mondini deformity) (5 ears), vestibular and semicircular canal malformations (14 ears), enlarged vestibular aqueduct (16 ears, 6 of which had other malformations), and internal auditory canal malformation (8 ears, all accompanied by other malformations). Multislice spiral CT allows a comprehensively assessment of various congenital inner ear malformations through high-quality MPR and VRT reconstructions. Volume-rendering technique images can display the site and degree of the malformation 3-dimensionally and intuitionisticly. This is very useful to the cochlear implantation.

Multislice spiral CT morphological evaluation before lung volume reduction surgery with volume rendering technique

Objective To investigate the optimal volume rendering technique(VRT)reconstruction threshold intervals using multislice spiral computed tomography(MSCT),by which target areas of lung volume reduction surgery(LVRS)were well displayed.Methods Fifty-six patients with scheduled LVRS were examined using MSCT during expiration and subsequently divided into group A and group B.With reconstruction threshold intervals of-1024 to-960 HU and-1024 to-910 HU,respectively,VRT was applied to group A.Then the optimal threshold interval for target areas in LVR was determined.The determined threshold intervals of group A was applied to VRT reconstruction in group B and subsequently we counted and located bullae with diameters more than 3 cm on the resultant VRT images,analyzed the emphysema distribution types,and compared them with the findings on axial and multiple planar reform (MPR)images.Finally,the paired t-test was employed to assess the difference of bulla counting results between VRT and two-dimensional images.Results VRT reconstruction threshold intervals of-1024 to -960 HU was optimal in displaying the target areas in LVRS in group A.In group B,the distribution types of emphysema,the count and location of bullae on the resulting VRT images correlated well with source images(t=1.98,0.00,1.77,1.76 and 1.81;P0.05).The number of bullae in different lung lobes were:2 dimensional imges:(4.22±2.09),(4.44±2.59),(2.18±0.92),(3.54±2.03)and(4.40± 2.42),respectively;VRT:(4.12±2.12)、(4.44±2.59)、(2.18±0.87)、(3.50±1.99)、(4.28± 2.28),respectively.The resultant VRT findings of LVRS patients were verified in operation.Conclusion VRT reconstruction threshold intervals of-1024 to-960 HU well displayed distribution types of emphysema and the target areas in LVRS,which provided a novel method of preoperative evaluation and postoperative outcome prediction.

Measurements Before Endovascular Repair Of Abdominal Aortic Aneurysms. MR imaging with MRA vs. angiography and CT

1) To compare measurements obtained with MR imaging (MRI)/contrast-enhanced MR angiography (CE MRA) with measurements obtained with angiography (DSA) and CT, for stent-graft sizing of abdominal aortic aneurysms (AAA). 2) To compare MRA measurements obtained with the two post processing techniques MIP (maximum intensity projection) and VRT (3D volume rendering technique). The prospective study included 20 consecutive patients with AAA identified by DSA and CT as suitable for endovascular repair. For the study, MRI/CE MRA was performed. Five measurement variables for stent-graft sizing were chosen. Comparisons were made between MRI/CE MRA, DSA and CT, and between observers. Comparisons were also made between MIP and VRT. Significantly shorter lengths were obtained with MRA-MIP than with DSA. Three out of six diameter measurements were significantly smaller on MRI/CE MRA than on DSA and CT. No significant differences were found between the observers. One diameter measurement was significantly smaller on MIP than on VRT, while the other measurements showed no significant differences. The length measurements obtained with MRA-MIP were probably more correct than those with DSA. For more reliable diameter measurements with CE MRA, improvements of the technique, including VRT reconstructions and a standardized determination of the vessel boundaries, are needed.