Curved Planar Reformation Research Articles

RETRACTED: Variations in the labyrinthine segment of facial nerve canal revealed by high-resolution computed tomography

To study variations in the labyrinthine segment of fallopian canal and the associated middle and inner ear malformations. The high-resolution computed tomography (HRCT) images of the temporal bone in 24 patients with congenital variations in the labyrinthine segment of fallopian canal were analyzed retrospectively. The length of labyrinthine segment of the facial nerve and angle of the first genu of 10 normal subjects were also measured. Based on the original axial images, multi-planar reformation (MPR) and curved-planar reformation (CPR) images of bilateral ossicular chains, inner ear structure and fallopian canal were reconstructed. HRCT features of congenital variations in the labyrinthine segment of the facial nerve were analyzed, including its beginning site, dehiscence, length, angle of the first genu and the associated middle and inner ear malformations. Among the normal subjects, the length of labyrinthine segment of the facial nerve was 3.56±0.41mm, and angle of the first genu was 71.87±8.09°. Five types of variations in the labyrinthine segment of the facial nerve were found in 45 ears of 24 cases, including dehiscence in geniculate fossa in 25 ears, anteromedial displacement at the beginning site in 27 ears (widening of Bill's bar in 7 cases), enlargement of the angle of the first genu in 30 ears with an average value of 107.2° (96.0-126.0°), increase of length in 30 ears with an average length of 6.8mm (5.2-8.3mm) and bifurcation in one ear. Associated middle ear malformation in 6 ears and inner ear malformation in 36 ears were also found. A variety of congenital variations may occur in the labyrinthine segment of the facial nerve and they are often associated with middle or inner ear malformations, which can be clearly displayed by HRCT with MPR or CPR images.

Coronary artery analysis: Computer-assisted selection of best-quality segments in multiple-phase coronary CT angiography.

The authors are developing an automated method to identify the best-quality coronary arterial segment from multiple-phase coronary CT angiography (cCTA) acquisitions, which may be used by either interpreting physicians or computer-aided detection systems to optimally and efficiently utilize the diagnostic information available in multiple-phase cCTA for the detection of coronary artery disease. After initialization with a manually identified seed point, each coronary artery tree is automatically extracted from multiple cCTA phases using our multiscale coronary artery response enhancement and 3D rolling balloon region growing vessel segmentation and tracking method. The coronary artery trees from multiple phases are then aligned by a global registration using an affine transformation with quadratic terms and nonlinear simplex optimization, followed by a local registration using a cubic B-spline method with fast localized optimization. The corresponding coronary arteries among the available phases are identified using a recursive coronary segment matching method. Each of the identified vessel segments is transformed by the curved planar reformation (CPR) method. Four features are extracted from each corresponding segment as quality indicators in the original computed tomography volume and the straightened CPR volume, and each quality indicator is used as a voting classifier for the arterial segment. A weighted voting ensemble (WVE) classifier is designed to combine the votes of the four voting classifiers for each corresponding segment. The segment with the highest WVE vote is then selected as the best-quality segment. In this study, the training and test sets consisted of 6 and 20 cCTA cases, respectively, each with 6 phases, containing a total of 156 cCTA volumes and 312 coronary artery trees. An observer preference study was also conducted with one expert cardiothoracic radiologist and four nonradiologist readers to visually rank vessel segment quality. The performance of our automated method was evaluated by comparing the automatically identified best-quality segments identified by the computer to those selected by the observers. For the 20 test cases, 254 groups of corresponding vessel segments were identified after multiple phase registration and recursive matching. The AI-BQ segments agreed with the radiologist's top 2 ranked segments in 78.3% of the 254 groups (Cohen's kappa 0.60), and with the 4 nonradiologist observers in 76.8%, 84.3%, 83.9%, and 85.8% of the 254 groups. In addition, 89.4% of the AI-BQ segments agreed with at least two observers' top 2 rankings, and 96.5% agreed with at least one observer's top 2 rankings. In comparison, agreement between the four observers' top ranked segment and the radiologist's top 2 ranked segments were 79.9%, 80.7%, 82.3%, and 76.8%, respectively, with kappa values ranging from 0.56 to 0.68. The performance of our automated method for selecting the best-quality coronary segments from a multiple-phase cCTA acquisition was comparable to the selection made by human observers. This study demonstrates the potential usefulness of the automated method in clinical practice, enabling interpreting physicians to fully utilize the best available information in cCTA for diagnosis of coronary disease, without requiring manual search through the multiple phases and minimizing the variability in image phase selection for evaluation of coronary artery segments across the diversity of human readers with variations in expertise.

New hybrid reformations of peripheral CT angiography: do we still need axial images?

PurposeTo quantify the detectability of peripheral artery stenosis on hybrid CT angiography (CTA) reformations. MethodsHybrid reformations were developed by combining multipath curved planar reformations (mpCPR) and maximum intensity projections (MIP). Fifty peripheral CTAs were evaluated twice: either with MIP, mpCPR and axial images or with hybrid reformations only. Digital subtraction angiography served as gold standard. ResultsUsing hybrid reformations, two independent readers detected 88.0% and 81.3% of significant stenosis, respectively. However, CTA including axial images detected statistically significant more lesions (98%). ConclusionPeripheral CTA reading including axial images is still recommended. Further improvement of these hybrid reformations is necessary.

ADR--Anatomy-Driven Reformation.

Dedicated visualization methods are among the most important tools of modern computer-aided medical applications. Reformation methods such as Multiplanar Reformation or Curved Planar Reformation have evolved as useful tools that facilitate diagnostic and therapeutic work. In this paper, we present a novel approach that can be seen as a generalization of Multiplanar Reformation to curved surfaces. The main concept is to generate reformatted medical volumes driven by the individual anatomical geometry of a specific patient. This process generates flat views of anatomical structures that facilitate many tasks such as diagnosis, navigation and annotation. Our reformation framework is based on a non-linear as-rigid-as-possible volumetric deformation scheme that uses generic triangular surface meshes as input. To manage inevitable distortions during reformation, we introduce importance maps which allow controlling the error distribution and improving the overall visual quality in areas of elevated interest. Our method seamlessly integrates with well-established concepts such as the slice-based inspection of medical datasets and we believe it can improve the overall efficiency of many medical workflows. To demonstrate this, we additionally present an integrated visualization system and discuss several use cases that substantiate its benefits.

Clinical value of multi-slice computed tomography in the diagnosis of colonic neoplasms

In order to investigate the clinical value of multi-slice computed tomography (MSCT) in the diagnosis of colonic neoplasms,the clinical data of 57 patients who were confirmed as with colonic neoplasms were admitted to the Wuxi No.2 People's Hospital from June 2013 to June 2014.Patients received plain and enhanced scan of MSCT,multiplannar reconstruction (MPR),sliding thin-slab maximum intensity projection (STS-MIP) and curved planar reformation (CPR),and the results of these examinations were compared with the postoperative TNM stage.Of the 57 patients,tumors located at the cecum in 1 patient,ascending colon in 23 patients,hepatic region of the colon in 9 patients,transverse colon in 11 patients,splenic region of the colon in 1 patient,descending colon in 3 patients and sigmoid colon in 9 patients.The results of the CT examination were in accordance with the results of exploratory laparotomy.The wall of the intestine was irregular ring-like thickened in 57 patients.The thickening of the intestine ranged between 0.6-3.2 cm,and patients had intestinal stricture in different degrees.Sixteen patients had gas-fluid level and dilatation of the intestine and were presented with intestinal obstruction signs.Forty-two patients had nodular or mass shadow in sofi tissues,and the nodules or mass protruded into the intestinal cavity or outside of the intestinal cavity,and resulting in intestinal stricture.The junction of the mass and the adjacent intestinal wall was blurred or clear,and the thickness of the intestinal walls was normal.Carcinomatous ulcer was observed in 20 patients.The shape of the ulcer was crateriform.The serosa and (or) adjacent organs were invaded by the tumors in 47 patients.Twenty-seven patients had lymph node metastasis,including 6 had distal metastasis,4 had hepatic metastasis and 2 had pulmonary metastasis.The sensitivity and accuracy of the preoperative CT examination for T stage were 100.0％ (57/57) and 77.2％ (44/57),respectively.The sensitivity,specificity and accuracy of the CT examination for N stage were 67.9％ (19/28),72.4％ (21/29) and 70.2％ (40/57),respectively.The sensitivity,specificity and accuracy of the CT examination for M stage were 100.0％ (6/6),100.0％ (51/51) and 100.0％ (57/57),respectively.The results of CT examination for TNM stage were well correlated with the pathological examination for TNM stage (κ =0.592,0.514,1.000,P ＜0.05).MSCT scanning and post-processing technique are of important clinical value in depicting tumor location,size and morphology,delineating tumor extension,revealing lymph nodes and metastases,and confirming preoperative tumor TNM stage in patients with colonic neoplasms. Key words: Colonic neoplasms; Multi-slice spiral computed tomography ; Diagnosis

Vessel Visualization using Curved Surface Reformation

Visualizations of vascular structures are frequently used in radiological investigations to detect and analyze vascular diseases. Obstructions of the blood flow through a vessel are one of the main interests of physicians, and several methods have been proposed to aid the visual assessment of calcifications on vessel walls. Curved Planar Reformation (CPR) is a wide-spread method that is designed for peripheral arteries which exhibit one dominant direction. To analyze the lumen of arbitrarily oriented vessels, Centerline Reformation (CR) has been proposed. Both methods project the vascular structures into 2D image space in order to reconstruct the vessel lumen. In this paper, we propose Curved Surface Reformation (CSR), a technique that computes the vessel lumen fully in 3D. This offers high-quality interactive visualizations of vessel lumina and does not suffer from problems of earlier methods such as ambiguous visibility cues or premature discretization of centerline data. Our method maintains exact visibility information until the final query of the 3D lumina data. We also present feedback from several domain experts.

Application of 128 slice spriral CT in the measurement of anatomy of facial nerve canal before cochlear implantation

Objective To take the imaging anatomy and measurement of facial nerve canal for cochlear implantation patients,and to provide the reference for how to avoid the injury of facial nerve in the opreration.Methods 35 patients which would be given to cochlear implantation were taken 128 thin-slice CT scan preoperative,then using multi planar reformation (MPR) and curved planar reformation (CPR) techniques,the three-dimensional reconstruction were carried out,and referring the facial nerve anatomy of posterior tympanic facial recess approachartificial cochlear implantation,the relationship between the vertical segnent of facial nerve canal and facial recess,tympanic cavity structure was key displayed.The facial nerve canal sections in temporal bone were measured,and compared with measurement results of 35 cases of cochlear implant patients.Results 35 patients underwent 128-slice CT scan three-dimensional reconstruction of MPR and CPR techniques,the facial nerve segment was clearly displayed,and its vertical section of the posterior wall of the external auditory canal,facial recess distance was (3.31 + 0.88)mm,(1.89 + 0.29) mm,respectively,and the vertical segment of the facial nerve canal wall,the facial recess distance of intraoperative measurement was (3.22 + 0.69) mm,(1.85 + 0.26) mm,respectively,and there were.no significant difference between the the both results(all P ＞ 0.05).35 patients had no case of face paralysis.Conclusion 128-slice spiral CT thin scan combined with MPR and CPR techniques can understand the facial nerve canal and surrounding anatomical landmarks of the fine relationship,measurable facial nerve canal length,and provide basis for how to avoid facial nerve injury in the cochlear implant,temporal bone,and the other side of the skull base surgery. Key words: Cochlear Implantation ; Tomography scaners, X-Ray computed; Facial nerve canal measurement

Application value of multidetector computed tomography angiography in the diagnosis of aberrant right subclavian artery

Objective To evaluate the application value of multidetector computed tomography angiography (MDCTA) in the diagnosis of aberrant right subclavian artery (ARSA). Methods Retrospective analysis were applied on 5800 patients who underwent MDCTA on head and neck, and then the ARSA and other accompanied variations of branches of aortic arch were observed on using original images, maximum intensity projection (MIP), curved planar reformation (CPR) and volume rendering (VR). Results ARSA combined with left aortic arch was found in 52 cases, among which simple ARSA was seen in 21 cases (40.38%), ARSA with bilateral common carotid trunk (CCT) in 19 patients (36.54%), ARSA and anomalous origin of unilateral vertebral artery in 9 patients (17.31%), ARSA, CCT and left vertebral artery (LVA) originating from aortic arch in 3 cases (5.77%). Among the 52 ARSA cases, Kommerell diverticulum was found in 10 cases (19.23% ), and no aneurysmal change was seen in Kommerell diverticulums. Conclusion MDCTA can accurately reflect ARSA and other accompanied variations of branches of aortic arch, and is significant for clinical practice.

Assessment of ureteral obstruction in patients with compromised renal function: Value of Curved Planar Reformations in MDCT

ObjectiveTo evaluate the usefulness of MDCT using a curved planar reformation technique for the noninvasive assessment of the causes and level of ureteral obstruction in patients with compromised renal function. Patients and methodsBetween January 2012 and February 2013, 50 patients with clinical and sonographic manifestations of ureteral obstruction underwent non-contrast multidetector CT (MDCT) using a 16-slice machine. A total of 65 ureters were examined. Curved planar reformation images were performed to display the entire course of ureters in the same image. All patients had renal impairment with serum creatinine greater than 2.0mg/dl. The gold standard for diagnosis of the cause of obstruction was ureteroscopy and/or open surgery. The sensitivity, specificity and overall accuracy of MDCT using curved planar reformation in the diagnosis of ureteral obstruction were calculated in comparison with the gold standard. ResultsA total of 65 ureters were examined (35 unilateral, 15 bilateral). The most common cause of ureteric obstruction was ureteric stone representing 27/65 (41.5%), followed by ureteric stricture representing 23/65 (35.4%). The lower third was the most affected in our study, it was encountered in 38/65 ureters (58.46%). The total sensitivity, specificity and accuracy of CPR for the cause of the ureteric obstruction were 98.5%, 98.5% and 97.8%, respectively (P value >0.05). CPR also was more sensitive and accurate for the level of ureteral obstruction with a total sensitivity of 100% and accuracy of 100% (P value >0.001). ConclusionCurved planar reformation MDCT is a useful noninvasive technique which is accurate in diagnosing the cause and level of ureteral obstruction in patients with compromised renal functions and is helpful for planning the therapeutic management of such patients.

The Validity and Reliability of Preoperative Radiographic Canal Diameter Measurements of the Femur

The femoral canal is frequently measured preoperatively in cases where an intramedullary device is planned for operative fixation of a fracture. To our knowledge, a formal assessment of validity and reliability of preoperative canal measurements has not been previously performed. This study aims to determine the validity and reliability of preoperative canal measurements of the femur made on plain radiographs using comparison with curved planar reformation software as the gold standard. Fifty-six patients were identified based on availability of anterior-posterior (AP) and lateral radiographs of the femur and computed tomography (CT) of the lower extremity. Four "raters" measured the canal diameter at its narrowest point and the distance from the lesser trochanter to the isthmus on the AP, lateral radiograph, and CT. The width of the femoral nail on AP radiographs was also measured to determine magnification error. Curved planar reformation (CPR) was used to provide the most accurate calculation of the canal diameter. Compared to the isthmus position determined by CPR, the measurement was most accurate on an AP and the diameter of the canal was most accurate using coronal CT, followed by AP radiographs. The measured canal diameter of the fractured femur on APs was compared to that of the used implant and varied by 1mm. The AP plain radiographic measurement was found to be more accurate for determination of the canal diameter compared to the lateral radiograph. These findings confirm the utility of preoperative canal measurements in predicting the feasibility of placing a specific size intramedullary implant.

Vessel Visualization using Curvicircular Feature Aggregation

AbstractRadiological investigations are common medical practice for the diagnosis of peripheral vascular diseases. Existing visualization methods such as Curved Planar Reformation (CPR) depict calcifications on vessel walls to determine if blood is still able to flow. While it is possible with conventional CPR methods to examine the whole vessel lumen by rotating around the centerline of a vessel, we propose Curvicircular Feature Aggregation (CFA), which aggregates these rotated images into a single view. By eliminating the need for rotation, vessels can be investigated by inspecting only one image. This method can be used as a guidance and visual analysis tool for treatment planning. We present applications of this technique in the medical domain and give feedback from radiologists.

Study of pulmonary artery monitoring for intracranial and cervical artery angiography with dual energy CT

Objective To explore the application value of pulmonary artery monitoring program for intracranial and cervical artery angiography with dual-energy CT.Methods Sixty patients performed intracranial and cervical artery angiography with dual-energy CT were divided into two groups according to the random number table.Group A (optimization group,30 patients):the monitoring points were located in the main pulmonary artery,with threshold 150 HU,trigger delay time 8-9 s,pitch 0.9,and the iohexol (350 mg I/ml) 60-65 ml.Group B (conventional group,30 patients):the monitoring points were located in aortic arch,with threshold 100 HU,trigger delay time 5 s,and the iohexol (350 mg I/ml)60-70 ml.Patients with the body weight less than 75 kg were injected with the flow rate of 4.0 ml/s,and those weight greater than 75 kg or with body mass index (BMI) greater than 27 kg/m2 were 4.5 ml/s,following 40 ml saline solution with the same flow rate respectively.All images were transferred to Siemens Syngo workstation for further processing and analysis.The attenuation values were measured on axial images in the common carotid artery,internal and external carotid artery,vertebral and basilar artery,the horizontal segment of the middle cerebral artery,the subclavian vein of injection side,the proximal,middle and distal segment of jugular vein,the straight sinus and the superior sagittal sinus.Two experienced observers blinded independently evaluated the image quality of CTA,the impact of contrast material residues artifacts of subclavian vein of injected side and the affect of venous return factors on arterial image display.Images of volume rendering technique(VR),the maximum intensity projection (MIP),and curved planar reformation (CPR) were reconstructed using dual energy bone removal and Inspace and 3D software.The mean intraluminal attenuation of contrast material (HU),the volume of contrast material and the mean image quality scores were compared with t test between the two groups.Chi-square test was used to compare of image contrast agents residual artifacts,the absence segments of the root of the neck artery,and the degree of the jugular vein return in two groups.Results The mean CT values were 372-414 HU for each segment of artery showing no significant differences between two groups (P ＞ 0.05).In group A,the CT values of the jugular vein in proximal,middle,distal segment of the two sides were (95 ± 36),(95 ± 36),(131 ±58),(133 ± 57),(174 ± 68),and (180 ± 66) HU respectively.In group B,CT values were (135 ± 58),(137 ±59),(170 ±58),(181 ±58),(218 ±62),and (224 ±68) HU.The CT value of jugular venous in group A was significantly lower than that in group B (t =-3.30--2.54,P ＜ 0.05).Case numbers of contrast agent residual artifacts of injection side subclavian vein and the absence segments of root of the neck artery at the beginning in group A (5,11) were less than that in group B (12,24) (x2 =4.02,5.65,P ＜0.05).The degree of the jugular vein return in group A were lesser severely than that in group B (x2 =6.79,6.37,P ＜0.05).Below the level of carotid artery bifurcation:slight 5 patients,severe 1 patient in group A vs.slight 15 patients,severe 9 patients in group B.Above the level of carotid artery bifurcation:slight 9 patients,severe 6 patients in group A vs.slight 12 patients,severe 17 patients in group B.Image quality scores of group A (3.84 ± 0.40) was higher than that of group B (3.64 ± 0.63) (t =4.26,P ＜0.05).Conclusions Pulmonary Artery Monitoring combines with 60-65 ml contrast material optimization scheme for intracranial and cervical artery angiography with dual energy CT can significantly reduce the degree of jugular venous return and contrast material residues artifacts of subclavian vein of injected side.This technique is helpful to improve the work efficiency and image quality. Key words: Tomography,X-ray computed; Comparative study; Pulmonary artery

Assessment of ureteric obstruction with 16-MDCT: Curved planar reformats versus three-dimensional volume-rendered images and their corresponding maximum intensity projections

AimTo compare the sensitivity and diagnostic accuracy of curved planar reformation (CPR) image on the one hand versus combined volume-rendered (VR) image and its corresponding maximum intensity projection (MIP) image on the other hand for determination of the cause and level of ureteral obstruction. Materials and methodsThe study included 60 patients with clinical and sonographic manifestations of ureteral obstruction who underwent two-phase multidetector CT urography (MDCTU) using a 16-slice machine. A total of 82 ureters were examined. CPR images were performed to display the entire course of ureters in the same image. 3D VR reformats and their corresponding MIP were used to enhance visualization of opacified ureters. The sensitivity and accuracy of CPR, and combined 3D VR and MIP for diagnosis of ureteral obstruction were calculated and compared in reference to the gold standard. ResultsThe cause of ureteral obstruction was calculous in 28/82 ureters (34.14%), and noncalculous in 50/82 (61%). The lower third ureter was the most affected level in 48/82 ureters (58.5%). The total sensitivity and accuracy of CPR for the cause of the ureteric obstruction (97.5% and 95.3%, respectively) were higher than those of 3D VR and its corresponding MIP (75% and 73.2%, respectively). CPR also was more sensitive and accurate (total sensitivity of 100% and accuracy of 100%) compared with those of combined 3D VR and its corresponding MIP (79.5% and 75.9%, respectively) for the level of ureteral obstruction. ConclusionsCPR had superior diagnostic accuracy than 3D VR and MIP in detecting the cause and level of ureteral obstruction.

Multi-slice CT diagnosis of early acute appendicitis

Objective To investigate the value of multi-slice CT (MSCT) in diagnosing early acute appendicitis (AA).Methods From June 2008 to June 2011,abdomen MSCT images of 41 patients with acute simple appendicitis confirmed by surgery and pathology were evaluated retrospectively. Thirty-six patients with clinically confirmed normal appendix served as the control groups with 18 patients in complicated-normal-appendix (CNA) group and 18 patients in noncomplicated-normal-appendix (NCNA)group. The appendix was reconstructed by using multiplanar reformation (MPR) and curved planar reformation (CPR) techniques. The differences between early AA and normal appendix in appendiceal diameter,thickness of the appendiceal wall, maximum depth of the intraluminal appendiceal fluid (MDIAF), abnormal enhancement of the appendiceal wall, appendicolith and the periappendiceal abnormalities were evaluated and compared by using analysis of variance,R test and Chi-square test.Results The mean thickness of the appendiceal wall was (2.88 ±0.62),(2.58 -±0.50) and (2.73 ±0.53) mm in early AA,CNA and NCNA groups respectively,with no statistically significant difference among them ( F =1.73,P=0.19).The nean appendiceal diameter was (11.37 ± 1.94),(7.03 -±0.89),(6.75 ±0.63) mm,and median MDIAF was 4.05 (2.65-8.50),1.68 (0-.40),0 (0-1.90) mm in early AA,CNA and NCNA groups respectively,with statistically significant differences between early AA and the two normal appendix groups ( Z =7.02,7.24 ; P =0.00 ).The abnormal enhancement of appendiceal wall was found in 61.1％ (11/18) of early AA,16.7％ (3/18) of CNA and 11.1％ (2/18) of NCNA groups respectively,with statistically significant differences between early AA and the two normal appendix groups (x2 =12.83,P =0.00). Using a cutoff value of 7.8 mm of the appendiceal diameter and 2.6 mm of MDIAF for the early AA,the sensitivity,specificity and accuracy were 97.6％ (40/41),91.7％ (33/36) and 94.8％ (73/77),and 100.0％ (36/36),88.9％ (32/36) and 94.4％ (68/72),respectively.Conclusions MSCT is particularly useful for the diagnosis of early AA. When appendiceal diameter is greater than 7.8 mm,and MDIAF greater than 2.6mm,early AA can be diagnosed with confidence. Key words: Appendicitis; Tomography,X-ray computed

Fast plaque burden assessment of the femoral artery using 3D black-blood MRI and automated segmentation

Vessel wall imaging techniques have been introduced to assess the burden of peripheral arterial disease (PAD) in terms of vessel wall thickness, area or volume. Recent advances in a 3D black-blood MRI sequence known as the 3D motion-sensitized driven equilibrium (MSDE) prepared rapid gradient echo sequence (3D MERGE) have allowed the acquisition of vessel wall images with up to 50 cm coverage, facilitating noninvasive and detailed assessment of PAD. This work introduces an algorithm that combines 2D slice-based segmentation and 3D user editing to allow for efficient plaque burden analysis of the femoral artery images acquired using 3D MERGE. The 2D slice-based segmentation approach is based on propagating segmentation results of contiguous 2D slices. The 3D image volume was then reformatted using the curved planar reformation (CPR) technique. User editing of the segmented contours was performed on the CPR views taken at different angles. The method was evaluated on six femoral artery images. Vessel wall thickness and area obtained before and after editing on the CPR views were assessed by comparison with manual segmentation. Difference between semiautomatically and manually segmented contours were compared with the difference of the corresponding measurements between two repeated manual segmentations. The root-mean-square (RMS) errors of the mean wall thickness (t(mean)) and the wall area (WA) of the edited contours were 0.35 mm and 7.1 mm(2), respectively, which are close to the RMS difference between two repeated manual segmentations (RMSE: 0.33 mm in t(mean), 6.6 mm(2) in WA). The time required for the entire semiautomated segmentation process was only 1%-2% of the time required for manual segmentation. The difference between the boundaries generated by the proposed algorithm and the manually segmented boundary is close to the difference between repeated manual segmentations. The proposed method provides accurate plaque burden measurements, while considerably reducing the analysis time compared to manual review.

Diagnostic ability of MDCT to assess right hepatic artery invasion by perihilar cholangiocarcinoma with left‐sided predominance

There have been few reports on the diagnostic ability of multidetector-row computed tomography (MDCT) to assess invasion of the hepatic artery. The aim of this study was to assess the diagnostic ability of MDCT for right hepatic artery (RHA) invasion. From August 2006 to October 2010, 103 consecutive patients with left-sided predominance perihilar cholangiocarcinoma underwent left-sided hepatectomy; all patients received MDCT as a preoperative workup. Three-dimensional volume-rendered and multiplanar reformation (MPR) images were retrospectively examined for evidence of RHA invasion, and the agreement between intraoperative macroscopic and histologic findings was assessed. No macroscopic evidence of RHA invasion was found in any of the 50 patients presenting visible low-density planes on MPR images between the RHA and adjacent tumor. Of the remaining 53 patients without visible low-density planes, 38 patients presented macroscopic evidence of RHA invasion and underwent combined RHA resection; the other 15 patients did not exhibit RHA invasion. The RHA contact length, as measured on MDCT images by curved planar reformations, was significantly longer in the former 38 patients than in the latter 15 patients (24.3 ± 16.9 vs. 8.6 ± 3.0 mm, respectively, P = 0.001). Histologic cancer infiltration of the resected RHA was found in 18 (47.4%) of the 38 patients who underwent RHA resection. Diagnosis of macroscopic RHA invasion based on the presence or absence of a low-density plane had an accuracy of 85.4%. We conclude that MDCT is useful for assessing RHA invasion by perihilar cholangiocarcinoma.

Comparative study on diagnosis of obstruction of bile duct by cholangiopancreatic multi planar reformations and curved planar reformatted image using 16-slice spiral CT of low field MRI and MRCP

Objective To evaluate the clinical application value of 16-slice spiral CT multi planar reformations(MPR) and curved planar reformations(CPR) in diagnosis of biliary obstructive disease. Methods 31 cases with obstruction of bile duct received 16-slice CT scanning and low field MRI, MRCP at the same time.All cases had pathology by operation or ERCP. All patients were reconstructed through multi planar reformations, curved reformatted technique and oblique anteroposterior axial location of muhiplanar reconstruction, and compared with MRCP,low field MRI, meanwhile also compared with operative pathology. Results There were no obvious difference for position identifying of obstruction of bile duct between cholangiopancreatic multi planar reformation, curved reformatted image using16-slice spiral CT, MRCP and low field MRI, the diagnosis in qualitation of obstruction, especially in diagnosing obstruction caused by gallstone, the former was better than the latter. Conclusion Using the cholangiopancreatic multi planar reformations curved reformatted method of 16 -slice spiral CT has very important value in the diagnosis of obstruction of bile duct. Key words: 16-slice spiral CT; Multi planar reformations; Curved planar reformations; Biliary obstructive disease

Interactive navigation of segmented MR angiograms using simultaneous curved planar and volume visualizations

Interactive visualization is required to inspect and monitor the automatic segmentation of vessels derived from contrast-enhanced magnetic resonance angiography (CE-MRA). A dual-view visualization scheme consisting of curved planar reformation (CPR) and direct volume rendering (DVR) was developed for this purpose and tested. A dual view visualization scheme was developed using the vessel pathline for both camera position and rotation in 3D, greatly reducing the degrees of freedom (DOF) required for navigation. Pathline-based navigation facilitates coupling of the CPR and DVR views, as local position and orientation can be matched precisely. The new technique was compared to traditional techniques in a user study. Layperson users were required to perform a visual search task that involves checking for (minor) errors in segmentations of MRA data from a software phantom. The task requires the user to examine both views. Pathline-based navigation and coupling of CPR and DVR provide user speed performance improvements in a vessel inspection task. Interactive MRA visualization with this method, where rotational degrees of freedom were reduced, had no negative effect. The DOF reduction achieved by the new navigation technique is beneficial to user performance. The technique is promising and merits comprehensive evaluation in a realistic clinical setting.

Curved Planar Reformatted Images of MDCT for Differentiation of Biliary Stent Occlusion in Patients With Malignant Biliary Obstruction

We prospectively evaluated the usefulness of MDCT using a curved planar reformation technique for the noninvasive assessment of the causes of biliary stent occlusion in patients with malignant biliary obstruction. Between December 2004 and January 2009, 173 patients with unresectable malignant biliary obstruction underwent biliary stent insertion. Among them, 26 patients with suspected biliary stent occlusion underwent 29 sessions of ERCP within 2 weeks after MDCT was performed. Curved planar reformation images were obtained along the pathway of the biliary stent. We interpreted tissue growth or stent clogging by comparing attenuation values inside the biliary stent between the unenhanced and contrast-enhanced phases of CT. The cause of biliary stent occlusion was confirmed by using ERCP. The differences in attenuation value inside the biliary stent between the contrast-enhanced and unenhanced phases of CT in the tissue growth group was 27.7 +/- 21.7 HU (SD) and 4.2 +/- 10.6 HU in the stent-clogging group (p = 0.002). The sensitivity and specificity of MDCT for the diagnosis of tissue growth were 86.7% and 85.7%, respectively. The overall accuracy of curved planar reformation images of MDCT for diagnosing the causes of stent occlusion was 86.2%. Curved planar reformation MDCT is a useful noninvasive technique that is relatively accurate for diagnosing the cause of biliary stent occlusion and is helpful for planning the therapeutic management of such patients.

Multimodal Vessel Visualization of Mouse Aorta PET/CT Scans

In this paper, we present a visualization system for the visual analysis of PET/CT scans of aortic arches of mice. The system has been designed in close collaboration between researchers from the areas of visualization and molecular imaging with the objective to get deeper insights into the structural and molecular processes which take place during plaque development. Understanding the development of plaques might lead to a better and earlier diagnosis of cardiovascular diseases, which are still the main cause of death in the western world. After motivating our approach, we will briefly describe the multimodal data acquisition process before explaining the visualization techniques used. The main goal is to develop a system which supports visual comparison of the data of different species. Therefore, we have chosen a linked multi-view approach, which amongst others integrates a specialized straightened multipath curved planar reformation and a multimodal vessel flattening technique. We have applied the visualization concepts to multiple data sets, and we will present the results of this investigation.