Multislice Computed Tomography Imaging Research Articles

Finite Element Analysis of Tricuspid Valve Deformation from Multi-slice Computed Tomography Images.

Despite the growing clinical interest in the tricuspid valve (TV), there is an incomplete understanding of TV biomechanics which is important in normal TV function and successful TV repair techniques. Computational models with patient-specific human TV geometries can provide a quantitative understanding of TV biomechanic. Therefore, this study aimed to develop finite element (FE) models of human TVs from multi-slice computed tomography (MSCT) images to investigate chordal forces and leaflet stresses and strains. Three FE models were constructed for human subjects with healthy TVs from MSCT images and incorporated detailed leaflet geometries, realistic nonlinear anisotropic hyperelastic material properties of human TV, and physiological boundary conditions tracked from MSCT images. TV closure from diastole to systole was simulated. Chordal lengths were iteratively adjusted until the simulated TV geometries were in good agreement with the "true" geometries reconstructed from MSCT images at systole. Larger chordal forces were found on the strut (or basal) chords than on the rough zone chords and the total forces applied on the anterior papillary muscles by the strut chords were higher than those on the posterior or septal papillary muscles. At peak systolic pressure, the average maximum stress on the middle sections of the leaflets ranged from 30 to 90kPa, while the average maximum principal strain values ranged from 0.16 to 0.30. The results from healthy TVs can serve as baseline biomechanical metrics of TV mechanics and may be used to inform TV repair device design. The computational approach developed could be one step towards developing computational models that may support pre-operative planning in complex TV repair procedures in the future.

Multislice Computed Tomography Imaging of Total Anomalous Pulmonary Venous Circulation: Three Rare Case Reports

Total anomalous pulmonary venous connection is a rare congenital cardiac anomaly in which the pulmonary veins have no connection with the left atrium and connect directly to the right atrium or to one of the systemic veins. In the diagnosis of total anomalous pulmonary venous connection, the presence and severity of the venous obstruction is important. Computed Tomography (CT) imaging is known to be a useful method for the evaluation of total anomalous pulmonary venous connection. Here we report 3 cases of total anomalous pulmonary venous circulation (TAPVC) where 32 slice CT scan played an important role in pre-operative diagnosis and management. Age of the patients ranged from seven months to sixteen years. Symptoms of the patients’ varied from fatigue, shortness of breath, mild cyanosis and reduced growth for their age. Echocardiography done revealed dilated right cardiac chambers and atrial septal defect (ASD) with suspicion of TAPVC. CT scan was performed and it provided detailed information about intra-cardiac anatomy, pulmonary veins and their confluence, route, drainage and most importantly their distance and relation with the left atrium. It also provided information about coronary sinus and its drainage. This information is very important for surgical mapping and planning.
 Ibrahim Card Med J 2016; 6 (1&2): 73-77

The gray scale value of ear tissues undergoing volume-rendering high-resolution cone-beam computed tomography

ObjectiveWhen the thresholds for VR reconstruction from multi-slice CT images are changed, problems develop when assessing pathologies in the absence of standardized thresholds. The advantages of CBCT include lower radiation exposure compared with other techniques and better visualization of small ear structures. However, a disadvantage is that the scanner provides unstandardized gray scale values, thus not CT numbers (Hounsfield units, HU). MethodsWe analyzed 88 sets of volume data obtained from temporal bones. The gray scale values were measured in aerated areas (two sites), along the ossicular chain (four sites) and in a bone area (one site) in the external and middle ears, and in soft tissue areas (five sites) and bone areas (two sites) in the inner ear. ResultsThe standard male and female gray scale values were 2448–2970 and 2585–3091 for the aerated areas, 3248–4945 and 3359–5223 for the ossicular chains, 3368–4109 and 3371–4147 for soft tissues, and 4790–5776 and 5044–5959 for bone, respectively. Sex significantly affected the values (p<0.05). Significant differences between aerated areas and ossicular chains, and between soft tissues and bone, were evident (all p<0.0001). ConclusionVolume-rendering (VR) images obtained by cone-beam computed tomography (CBCT) can be standardized simply by using fixed thresholds.

Role of Contrast Enhancement and Corrected Attenuation Values of Renal Tumors in Predicting Renal Cell Carcinoma (RCC) Subtypes: Protocol for a Triphasic Multi-Slice Computed Tomography (CT) Procedure.

SummaryBackgroundTo distinguish RCC subtypes based on contrast enhancement features of CT images.Material/MethodsIn total, 59 lesions from 57 patients were included. All patients underwent multi-slice CT imaging with a triphasic protocol, which included non-contrast, corticomedullary, nephrographic and urographic phases. Contrast enhancement features of renal masses were evaluated in terms of CT attenuation values (AV) and differences in contrast density; the aorta or renal parenchyma were evaluated based on corrected or relative values.ResultsClear cell RCC (ccRCC) showed more intense contrast enhancement than other RCC subtypes. When differentiating ccRCC from other RCC subtypes, a cut-off AV of 86–89 HU, aorta-based corrected AV of 89–95 HU and renal parenchyma-based corrected AV of 87–95 HU showed a diagnostic accuracy of 81–86%, 86–88% and 74–78%, respectively, in the corticomedullary phase. Furthermore, a cutoff of 2.42–2.72 for the relative contrast enhancement ratio, a cutoff of 2.59–2.74 for the aorta-based corrected relative contrast enhancement ratio and a cutoff of 2.63–2.76 for the renal parenchyma-based attenuation ratio showed a diagnostic accuracy of 83–88%, 88–90% and 81%, respectively.ConclusionsThe most reliable parameters for differentiating ccRCC from other RCC subtypes are aorta-based corrected AV and aorta-based corrected relative contrast enhancement values in the corticomedullary phase.

Comparison between multi-slice spiral CT and magnetic resonance imaging in the diagnosis of peritoneal metastasis in primary ovarian carcinoma.

The advent of disease evaluation by means of multi-slice spiral computed tomography (MSCT) and magnetic resonance imaging (MRI) represents a continually emerging role in the evaluation of various diseases; however, its role is yet to be adequately defined. Thus, the aim of the study was to compare the diagnostic value of MSCT and MRI in the diagnosis of peritoneal metastasis in primary ovarian carcinoma. Between January 2013 and December 2015, MSCT or MRI data were collected from 42 patients who had been previously diagnosed with peritoneal metastasis of ovarian carcinoma at the First Affiliated Hospital of Kunming Medical University. The tumor location, size, edge, and shape were all evaluated independently by three qualified imaging physicians using a double-blind method to confirm whether the patients were indeed suffering from peritoneal metastasis, as well as to rank the metastatic lesions recorded on a five-point scale. It was hypothesized that MRI and MSCT were comparable in the evaluation of ovarian carcinoma. Therefore, a receiver operating characteristics (ROC) curve was used to analyze the results and also to directly compare the respective diagnostic values of MSCT and MRI. In total, 165 metastatic lesions were confirmed by means of surgical operation. MSCT revealed 131 metastatic lesions, while MRI confirmed 154 metastatic lesions. The metastatic sites were primarily located on the subphrenic, epiploon, and gastrocolic ligaments and were further confirmed by either MRI or CT. In regard to MSCT, the most common site of underdiagnoses was in the vicinity of the uterus–rectum–fossa. MRI displayed a high detection rate in every site. The omission diagnostic rate of MSCT and MRI were 20.61% and 6.67%, respectively, while the accuracy rates were 79.39% and 93.33%, respectively. The obtained results revealed that the MSCT value of area under the ROC curve was smaller than that for MRI. Our findings provided evidence asserting that MRI, in comparison to MSCT, was more accurate in diagnosing peritoneal metastasis in patients with ovarian carcinoma.

The diagnostic value of multi-slice spiral computed tomography in patients with renal carcinoma.

This study was aimed to investigate the characteristics of multi-slice spiral computed tomography (CT) image in kidney cancer patients and its clinical value in staging diagnosis of kidney cancer. This study included 57 patients who were confirmed as kidney cancer through postoperative pathological examination; they were diagnosed within February 2014 and December 2016 in our hospital. The data obtained from multi-slice spiral CT plain scan and contrast-enhanced CT of these patients was retrospectively analyzed. Moreover, we determined the characteristics of multi-slice spiral CT image for kidney cancer and analyzed their consistency with pathological staging. CT plain scan showed that kidney lumps were mostly found in the prominent renal contour or renal parenchyma, and they were round-like or round in shape. Among the 57 included patients, the tumors of 43 cases showed regular edges, and 14 showed irregular edges. Among the 14 cases, 10 patients had tumors with lobulated edges and 5 with spinous tumor edge. Among all the 57 patients, CT plain scan showed there were 5 cases with slightly higher density, 24 cases with mixed density, 28 cases with equal density or slightly lower density. The range of tumor diameter was 2.1-12.6 cm; the tumor diameter was smaller than 3 cm in 11 cases, 3-7 cm in 34 cases, and larger than 7 cm in 12 cases. In terms of contrast enhancement, the arterial phase was obviously enhanced in 31 cases, moderately and irregularly enhanced in 18 cases, and slightly enhanced in 8 cases. Moreover, the renal parenchymal scan showed a rapid decline in the enhancement and a further decline in the enhancement of renal pelvic tumor; the three stages of enhancement could be expressed in terms of fast forwardness and fast backwardness. A total of 33, 4, 9, and 11 cases were classified as postoperative pathological Stage I, II, III, and IV, respectively; 35, 5, 7, and 10 cases were classified as CT scan Stage I, II, III, and IV, respectively; and 34, 5, 8, and 10 cases were classified as contrast-enhanced CT scan Stage I, II, III, and IV, respectively. No significant difference was observed in the frequency of CT scan, the enhanced stage and pathological stage (P > 0.05). CT image of kidney cancer revealed the morphological and enhanced features of this tumor. The consistency between CT stage and pathological stage was high; thus, this method can be applied as a forecasting method for pathological staging.

Multi-slice CT imaging analysis of basal cell adenoma in the parotid gland

Objective To investigate the CT imaging features of basal cell adenoma in the parotid gland and thus to improve the preoperative diagnostic accuracy. Methods The clinical materials and image findings of 8 cases with parotid basal cell tumor, which were proved by pathology, were retrospectively studied. Results All 8 patients had solitary BCA lesion, which involved both the superficial and deep lobe(n=1) and located at the superficial lobe of parotid gland(n=7). All the 6 tumors were clear boundary and round shape without lobular appearance.The diameters of the max lesions ranged from 10.3-27.6 mm.CT scan showed that all lesions were solid nodules with uniform or uneven density.Cystic degeneration was displayed in 5 lesions, among them, cystic area was ≥90% in 1 lesion.At enhanced scanning phase, most tumors showed a strong enhancement at the arterial phase and a pattern of persistent strong enhancement or slow decline at the venous phase. Conclusion The multi-slice CT imaging features of BCA in parotid gland are characteristic, which is helpful to make qualitative diagnosis in combination with clinical materials. Key words: Basal cell adenoma; Parotid tumor; Tomography, X-ray computed

Comprehending the three-dimensional mandibular morphology of facial asymmetry patients with mandibular prognathism

BackgroundThe purpose of this study was to elucidate the factors that cause facial asymmetry by comparing the characteristics of the mandibular morphology in patients with mandibular prognathism with or without facial asymmetry using three-dimensional computed tomography (3D-CT).MethodsWe studied 28 mandibular prognathism patients whose menton deviated by ≥ 4 mm from the midline (FA group, n = 14) and those with a < 4-mm deviation (NA group, n = 14). DICOM data from multislice CT images were reconstructed and analysed using 3D image analysing software. Mandibular structures were assessed via linear, angular, or volumetric measurements and analysed statistically.ResultsThe lengths of the ramal and body components and condylar volume in the FA group were significantly greater on the nondeviated side than those on the deviated side. The mandibular body length of the nondeviated side in the FA group was significantly longer than that of the NA group. Other components of the FA group did not significantly differ from those of the NA group.ConclusionsImbalances in the sizes of the ramal and body components as well as the increased body length of the nondeviated side in the FA group compared with that of the NA group may contribute to facial asymmetry in patients with mandibular prognathism.

Improvement of Dose Calculation with Scattered Photon-Corrected kV Cone-Beam CT Image Using the Kernel Deconvolution Method

Intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) has to be accomplished with a dose distribution in terms of changes in the tumor size and position for minimizing adverse effects on neighboring organs. If cone-beam computed tomography (CBCT) would facilitate dose calculation attached to the IMRT or SBRT apparatus, we could use the CBCT-based adaptive radiation therapy (ART). However, a CBCT image cannot achieve quantitative electron density values owing to scattered photons; thus, we cannot use it directly for dose calculation. In this study, we calculated the distribution of scattered photons in CBCT images using the Monte Carlo (MC) method and corrected the scattered photon effect with scatter kernels in the process of image reconstruction with the maximum likelihood expectation maximization (MLEM) method. Moreover, we investigated the accuracy of dose calculation by this segmented region method in comparison with typical methods by replacing CBCT values with ideal density values. We calculated the distribution of scattered photons with slab phantoms using the MC method and acquired scattered kernels of three materials (bone, water, and lungs) having different thicknesses until 20 cm every 0.1 cm. These kernels were used in the MLEM method for correcting scattered photons in lung and pelvis CBCT images. Next, we segmented CBCT and multislice CT (MSCT) images into three regions (lungs, bones, and soft tissues) and compared segmentation accuracy between MSCT and scatter-corrected CBCT images. Moreover, we evaluated the effectiveness of dose calculation by CBCT images. In the CBCT to density conversion method, we converted the CBCT value using individual three tables in each organ, and in the density overriding method, we observed calculated doses on accurate organ-segmented images using γ and dose–volume histogram (DVH) analyses. Segmentation results showed that the threshold value of bone and soft tissue separation was similar to the ideal threshold value used in MSCT images; the segmentation error ratio improved (w/o: 63.0%, w/: 4.7%). Similarly, segmentation error ratios for lungs and soft tissues improved by 8.6% compared with those observed on the original CBCT image. In the CBCT to density conversion method, differences in target doses of MSCT and CBCT with scatter corrections were small in the DVH analysis. In the density overriding method, γ analysis results showed that the calculated dose distributions with scatter-corrected images were similar to those seen in MSCT; the pass rate was significantly higher with an accurate segmentation effect (w/o: 70.1%, w/: 95.9%). We evaluated the effectiveness of scattered photon-corrected CBCT image using the kernel deconvolution method for organ segmentation and the effect of this contribution on dose calculation. Improvement of the segmentation accuracy with scattered photon correction can be observed using CBCT dose calculation for ART.

Forensic Identification of Decomposed Human Body through Comparison between Ante-Mortem and Post-Mortem CT Images of Frontal Sinuses: Case Report.

ObjectiveThe aim of this paper is to report on a case of positive human identification of a decomposed body after the comparison of ante-mortem (AM) and port-mortem (PM) computed tomography images of frontal sinus.Case reportAn unknown, highly decomposed human body, aged between 30 and 40 years, was found in a forest region in Brazil. The dental autopsy revealed several teeth missing AM and the presence of removable partial prostheses. The search for AM data resulted in a sequence of 20 axial images of the paranasal sinuses obtained by Multislice Computed Tomography (MSCT). PM reproduction of the MSCT images was performed in order to enable a comparative identification. After a direct confrontation between AM/PM MSCT, the data were collected for morphological findings, specifically for the lateral expansion of the left lobe, the anteroposterior dimension, and the position of median and accessory septa of the sinuses.ConclusionThe importance of storing and interpreting radiographic medical data properly is highlighted in this text, thus pointing out the importance of application of forensic radiology in the field of law.

Role of Multislice CT Imaging in Predicting the Visibility of the Round Window in Pediatric Cochlear Implantation.

High-resolution computed tomography (HRCT) magnifies the role of preoperative imaging for detailed inner and middle ear anatomical information and enhances more efforts for better dependent correlation and measurements of round window (RW). To find an applicable way by HRCT imaging for the prediction of the visibility of the RW during cochlear implantation (CI) surgery. Five radiologic measurements were performed on the axial HRCT and these measurements were correlated with the degree of RW visibility after performing posterior tympanotomy during CI surgery. Sixty ears of 60 children were included in the current study. A significant correlation was found between the degree of RW visibility and the following: 1) the angle between RW, facial nerve (FN), and the coronal axis (p < 0.00001); 2) the vertical distance between RW and FN (p = 0.006552); and 3) FN location to the axis of cochlea (p = 0.000419). On the other hand, nonsignificant correlation was found between the degree of RW visibility and both of the facial recess width and the angle between axis of cochlea and external auditory canal (p = 0.941363 and p = 0.59036 respectively). The angle between RW, FN, and the coronal axis and the vertical distance between RW and FN are proportionate with the degree of surgical RW visibility in children during CI. In children, surgeons can depend on those two parameters in addition to the distance between FN location to the axis of cochlea in predicting the RW visibility rather than depending on the measurements related to the external auditory canal.

Differences of CT pulmonary function indexes in asbestosis patients engaged in different types of work

Objective To evaluate the changes and characteristics of pulmonary function in asbestosis patients engaged in different types of work by multi-slice spiral CT imaging. Methods Total 30 asbestosis patients were equally divided into three groups, who engaged in the work of raw asbestos processing, fiber combing and pressure molding, respectively. The pulmonary volume, pulmonary density and pulmonary small airway indexes were measured by a whole lung scanning at maximum inspiratory and maximum expiratory efforts. The pulmonary volume indexes include maximum inspiratory volume, maximum expiratory volume, pulmonary volume difference and pulmonary volume ratio. The mean pulmonary density indexes include the mean pulmonary densities after inspiratory and expiratory activities, pulmonary density difference and pulmonary density ratio. The small airway indexes include the diameter ratios of the wall after inspiratory and expiratory activities and the percentage of bronchial wall area after inspiratory activity. Results The differences of the gender, age, stage, and contact history of the patients are not statistically significant for all the groups (all P>0.05). The differences of the mean pulmonary densities after expiratory activity, the left and right pulmonary densities after expiratory activities, pulmonary density ratio, diameter ratios of the wall after inspiratory and expiratory activities, and the percentage of bronchial wall area after inspiratory activity are statistically significant among the three groups (all P 0.05). The differences among the three groups in other indexes are not statistically significant (all P>0.05). Conclusions The emphysema with fibrous thickening in the alveolar septum and small airway wall is more severe in the workers who engaged in asbestos fiber combing comparing with in raw asbestos processing and asbestos pressure molding. Therefore, the medical protection of these groups of patients should be strengthened. Key words: Asbestosis; Respiratory dysfunction; Occupation

Modeling Left Ventricular Blood Flow Using Smoothed Particle Hydrodynamics.

This study aims to investigate the capability of smoothed particle hydrodynamics (SPH), a fully Lagrangian mesh-free method, to simulate the bulk blood flow dynamics in two realistic left ventricular (LV) models. Three dimensional geometries and motion of the LV, proximal left atrium and aortic root are extracted from cardiac magnetic resonance imaging and multi-slice computed tomography imaging data. SPH simulation results are analyzed and compared with those obtained using a traditional finite volume-based numerical method, and to in vivo phase contrast magnetic resonance imaging and echocardiography data, in terms of the large-scale blood flow phenomena usually clinically measured. A quantitative comparison of the velocity fields and global flow parameters between the in silico models and the in vivo data shows a reasonable agreement, given the inherent uncertainties and limitations in the modeling and imaging techniques. The results indicate the capability of SPH as a promising tool for predicting clinically relevant large-scale LV flow information.

Image-based fluid dynamics analysis of left ventricle outflow tract pressure gradient after deployment transcatheter mitral valve.

The goal of this study was to develop an image-based model to computational investigate blood flow and pressure gradients resulting from left ventricular (LV) wall motion after the implantation of a mitral valve (MV) prosthesis. Two image-based 3D models were reconstructed from multi-slice computed tomography images obtained from patients undergoing transcatheter MV replacement. Navier-Stokes equations were then used to compute the fluid motion. Outflow tract obstruction of the models with MV prosthesis were identified by calculating the difference between LV systolic and aortic pressures. It was found that computed outflow track obstruction compared well with actual obstruction data obtained from two patients. Our study indicates computational modeling can be a valuable tool to investigate the optimal placement of prosthetic valves guided by individualized anatomical data.

Evaluation of respiratory dysfunction in patients with asbestos lung based on pulmonary function indexes utilizing CT

Objective To evaluate the changes and characteristics of respiratory function and pulmonary function in patients with asbestosis by multi-slice spiral CT imaging. Methods 61 asbestosis patents and 30 healthy subjects were enrolled and divided into normal respiratory function group, mild injury group and moderate/severe injury group according to forced vital capacity and forced expiratory volume in one second. The lungs were scanned at the end of inspiratory and expiratory phase, and the lung volume, lung density and small airway index were measured. Results There were significant differences in lung volume (inspiratory and expiratory volume, volume difference, and volume ratio) among the normal group, the mild injury group and the moderate/severe injury group (all P<0.05). There were statistically significant differences in the mean lung density (lung density at the end of inspiratory and expiratory phase, lung density difference, lung density ratio) among the three groups (all P<0.05). There were significant differences in the small airway indexes (tracheal wall thickness ratio at the end of inspiratory and expiratory phase, bronchial wall area ratio) among the three groups (all P<0.05). Conclusions CT lung function imaging techniques can be used to assess the degree of respiratory dysfunction in asbestosis patients. With the development of pulmonary respiratory dysfunction, the total lung volume decreased, the amount of lungs gradually increased, emphysema gradually increased, and the thickness of small airway wall and alveolar fibrous hypertrophy gradually increased. Key words: Asbestosis; Pulmonary respiratory dysfunction; Pulmonary function

Value of multi-slice spiral CT image texture analysis in diagnosing lymphatic metastasis of rectal cancer

Objective To investigate the value of multi-slice spiral CT image texture analysis in differentiating metastatic (MLN) from non-metastatic lymph nodes (NLN) in patients with rectal cancer. Methods Thirty five patients with rectal cancer who were pathologically confirmed by total mesorectum excision were included retrospectively, with regional lymph nodes (short-axis diameter of larger than 3 mm) found in preoperative CT images. All the patients underwent preoperative abdominal and pelvic dynamic contrast-enhanced CT scan. Regional lymph nodes were identified according to pathological findings, and were divided into MLN and NLN groups. The short-axis diameter, short-to long-axis diameter ratio of lymph nodes were manually measured and calculated, and the texture features, including skewness, kurtosis, variance, entropy and inverse difference moment, were analyzed. The above parameters between MLN and NLN groups were compared using independent sample t test or Mann-Whitney U test. ROC curve analysis was performed regarding the statistically significant parameters and the areas under curve (AUC) were calculated. Multivariate Logistic regression analysis was accomplished to obtain the independent predictive factor of diagnosing regional lymph nodes. Results A total of 68 regional lymph nodes were obtained and consisted of 31 MLNs and 37 NLNs. The short-axis diameter, kurtosis, and entropy of the MLN group were significantly higher than those of the NLN group (all P 0.05). The AUC for distinguishing MLN from NLN of the short-axis diameter, kurtosis and entropy were 0.79, 0.67, and 0.85, respectively. Multivariate logistic regression analysis showed that only entropy (odds ratio= 8.48, 95% confidence interval was 3.01 to 23.92, P<0.01) was screened out as the independent variable, which suggested that the entropy was the unique predictor for characterizing regional lymph nodes of rectal cancer. Conclusion Multi-slice spiral CT images texture analysis can facilitate the accurate differentiation between MLN and NLN in patients with rectal cancer, and especially the entropy has the optimal reference significance. Key words: Rectal neoplasms; Lymphatic metastasis; Tomography, X-ray computed; Texture analysis

Impact of prone, supine and oblique patient positioning on CBCT image quality, contrast-to-noise ratio and figure of merit value in the maxillofacial region.

To assess the impact of supine, prone and oblique patient imaging positions on the image quality, contrast-to-noise ratio (CNR) and figure of merit (FOM) value in the maxillofacial region using a CBCT scanner. Furthermore, the CBCT supine images were compared with supine multislice CT (MSCT) images. One fresh frozen cadaver head was scanned in prone, supine and oblique imaging positions using a mobile CBCT scanner. MSCT images of the head were acquired in a supine position. Two radiologists graded the CBCT and MSCT images at ten different anatomical sites according to their image quality using a six-point scale. The CNR and FOM values were calculated at two different anatomical sites on the CBCT and MSCT images. The best image quality was achieved in the prone imaging position for sinus, mandible and maxilla, followed by the supine and oblique imaging positions. 12-mA prone images presented high delineation scores for all anatomical landmarks, except for the ear region (carotid canal), which presented adequate to poor delineation scores for all studied head positions and exposure parameters. The MSCT scanner offered similar image qualities to the 7.5-mA supine images acquired using the mobile CBCT scanner. The prone imaging position offered the best CNR and FOM values on the mobile CBCT scanner. Head positioning has an impact on CBCT image quality. The best CBCT image quality can be achieved using the prone and supine imaging positions. The oblique imaging position offers inadequate image quality except in the sinus region.

Multi-slice spiral CT in the diagnosis of pulmonary sclerosing hemangioma

Objective To analyze the CT imaging features of pulmonary sclerosing haemangioma(PSH), so as to improve the level of the diagnosis of this disease. Methods Retrospectively analyzed the Multi-slice spiral computed tomography(MSCT) imaging data of 13 cases of PSH with who confirmed by surgical pathology, all cases were performed CT with non-enhanced scaning and enhanced. Results 13 patients' average age was 42 years old, including 10 female, accounted for 76.92%(10/13). All the nodules or masses of the 13 cases were single, long diameter was 0.6-5.0cm, all tumors presented as round or oval shaped, clear boundary.1 case with calcifications in 13 cases, 2 cases with air meniscus sign, and 2 cases with halo sign around.Contrast-enhanced: 10 cases were enhanced homogeneously, 3 cases were enhanced heterogeneously and with vessel marginating sign, 1 case of lymph node was enlargement in mediastinal. Conclusion PSH mainly more shows at middle-aged women, it has relative characteristic of CT imaging within non-enhanced scaning and enhanced.Therefore, a comprehensive analysis of these CT features can help to improve the accuracy of diagnosis. Key words: Pulmonary; Selerosing hemangioma; Tomography, computed

Long-term serial non-invasive multislice computed tomography angiography with functional evaluation after coronary implantation of a bioresorbable everolimus-eluting scaffold: the ABSORB cohort B MSCT substudy

Multimodality invasive imaging of the first-in-man cohort demonstrated at 5 years stable lumen dimensions and a low rate of major adverse cardiac events (MACE). However, the long-term non-invasive assessment of this device remains to be documented. The objective was to describe the 72-month multislice computed tomography (MSCT) angiographic and functional findings after the implantation of the second iteration of the fully resorbable everolimus-eluting polymeric scaffold. In the ABSORB Cohort B trial patients with non-complex de novo lesions were treated with second iteration bioresobable vascular scaffold (BVS). MSCT angiography was performed as an optional investigation at 18 months; patients were reconsented for a second investigation at 72 months. MSCT data were analysed at independent core laboratories for quantitative analysis of lumen dimensions and for calculation of fractional flow reserve derived from computed tomography (FFRCT). From the overall Cohort B (101 patients), 53 patients underwent MSCT imaging at 72 months. The MACE rate was 1.9% (1/53). At 72 months, the median minimal lumen area (MLA) was 4.05 mm2 (interquartile range [IQR]: 3.15-4.90) and the mean percentage area stenosis was 18% (IQR: 4.75-31.25), one scaffold was totally occluded. In 39 patients with paired MSCT analysis, the MLA significantly increased from the first to the second follow-up (Δ = 0.80 mm2, P = 0.002). The change in the median FFRCT scaffold gradient between time points was zero. The long-term serial non-invasive MSCT evaluation with FFRCT assessment after bioresorbable scaffold implantation confirmed in-scaffold late lumen enlargement with the persistence of normalization of the FFRCT. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00856856.

Comparison of Cone Beam Computed Tomography and Multi Slice Computed Tomography Image Quality of Human Dried Mandible using 10 Anatomical Landmarks.

Cone Beam Computed Tomography (CBCT) has gained a broad acceptance in dentomaxillofacial imaging. Computed Tomography (CT) is another imaging modality for diagnosis and preoperative assessments of the head and neck region. Considering the increased radiation exposure and high cost of CT, this study sought to subjectively assess the image quality of CBCT and Multi Slice CT (MSCT). A dry human mandible was scanned by five CBCT systems (New Tom 3G, Scanora, CRANEX 3D, Promax and Galileos) and one MSCT system. Three independent oral and maxillofacial radiologists reviewed the CBCT and MSCT scans for the quality of 10 landmarks namely mental foramen, trabecular bone, Periodontal Ligament (PDL), dentin, incisive canal, mandibular canal, dental pulp, enamel, lamina dura and cortical bone using a five-point scale. Significant differences were found between MSCT and CBCT and among the five CBCT systems (p<0.05) in visualization of different anatomical structures. A fine structure such as the incisive canal was significantly less visible and more variable among the systems in comparison with other anatomical landmarks such as the mental foramen, mandibular canal, cortical bone, dental pulp, enamel and dentin (p<0.05). The Cranex 3D and Promax systems were superior to MSCT and all other CBCT systems in visualizing anatomical structures. The CBCT image quality was superior to that of MSCT even though some variability existed among different CBCT systems in visualizing fine structures. Considering the low radiation dose and high resolution, CBCT may be beneficial for dentomaxillofacial imaging.