Intensity Multiplanar Reconstruction Research Articles

Application of Multiplanar Volume Reconstruction Technique for the Assessment of Electrode Location and Analysis of the Correlation to Cochlear Programming and Performance in Common Cavity Deformity

Purpose: Owing to the characteristic anatomy, cochlear implantation (CI) for common cavity deformity (CCD) has resulted in varied outcomes and frequent facial and vestibular nerve stimulation. The current study analyzed the correlation among the distance between each electrode and cavity wall (abbreviation, D), programming parameters, and performances outcomes.Materials and Methods: The current, retrospective study included 25 patients (27 ears) with CCD underwent CI. The multiplanar volume reconstruction (MPVR) techniques were employed to reconstruct and evaluate the postoperative temporal bone CT. The D and maximum comfortable level (MCL) 6 months after CI, facial and vestibular nerve stimulation, and outcomes 1, 2, and 3 years after CI pertaining to the questionnaires were documented and analyzed.Results: The patients were divided into symptomatic (10, 37%) and asymptomatic (17, 63%) groups according to with or without facial and vestibular nerve stimulation. The MCL pertaining to the symptomatic group was significantly lower than asymptomatic group, but Categories of Auditory Performance (CAP) scores 1 year after surgery was better (p < 0.05). The subjects were divided into flat (12, 44.4%) and curved (15, 55.6%) groups based on the contour of MCL map. The MCL and D were lower and shorter in the curved group than the flat group, and CAP score 1 year after surgery and Speech Intelligibility Rating (SIR) 3 years after surgery were better (p < 0.05).Conclusion: Although abnormal reactions such as facial and vestibular nerve stimulation were observed to be more frequent, lower MCL and better outcomes were observed in relation to the shorter D.

A MRI study of lumbar plexus in patients with degenerative lumbar scoliosis after extreme lateral interbody fusion

To analyze the magnetic resonance neural imaging distribution of lumbar plexus in patients with degenerative lumbar scoliosis and evaluate its value and the safety of extreme lateral interbody fusion (XLIF). Three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) sequences of lumbar spine were scanned on 19 patients with degenerative lumbar scoliosis, including levo scoliosis (n = 11) and dextro scoliosis (n = 8). All images were sent to workstation for multiplanar volume reconstruction to analyze the distribution of lumbar plexus from L1-2 to L4-5 level. The axial image distance (AID) was measured between anterior edge of lumbar plexus and sagittal central perpendicular line (SCPL). SCPL was drawn perpendicularly to the sagittal plane of intervertebral disc and passed through its central point. It was actually the pathway of guide wire implanting procedure and the ongoing axis of work channel during XLIF. With respect to SCPL, the distance with a positive value indicated posterior neural tissue whereas a negative value anterior neural tissue. The differences of AID were compared between convex and concave sides and among different cases and levels. From L1-2 to L4-5 level, the AID on the concave side in levo scoliosis or dextro scoliosis cases was (13.7 ± 2.5) mm/ (12.9 ± 5.5) mm, (8.3 ± 4.7) mm/ (8.5 ± 5.7) mm, (2.7 ± 3.6) mm/ (2.5 ± 7.2) mm and (-4.2 ± 3.8) mm/ (-3.8 ± 7.1) mm respectively. They were located significantly posteriorly to the relevant disc compared to those on the convex side at the same intervertebral space (P < 0.05). The differences of AID at the same side, concave or convex side, was significant (P < 0.05). No significant differences of lumbar plexus distribution existed between levo scoliosis and dextro scoliosis cases (P > 0.05). Lumbar plexus passes through psoas posteriorly to SCPL on both side at L1-2, L2-3 level and on the concave side at L3-4 level. And they shift anteriorly to SCPL on the convex side at L3-4 level and on both sides at L4-5 level. It indicates a ventral migration of lumbar plexus from L1-2 to L4-5 level. Preoperative magnetic resonance neural imaging is valuable for assessing the safety of XLIF approach. Operation from the concave may reduce the risk of injury to lumbar plexus.

Role of multidetector CT angiography in the evaluation of suspected mesenteric ischemia

To assess the role of multidetector CT angiography (MDCTA) in the diagnosis of acute mesenteric ischemia (AMI) and to compare the diagnostic utility of axial images with reconstructed images. In this Institute Review Board approved prospective study, MDCTA was performed on 31 patients who presented with the clinical suspicion of AMI (25M; 6F, age range: 16-73 years). Axial and reconstructed images of each patient were evaluated independently by two radiologists for evidence of bowel wall thickening, abnormal mucosal enhancement, bowel dilatation or obstruction, mesenteric stranding, ascites, solid organ infarcts, pneumatosis intestinalis or porto-mesenteric gas, and mesenteric arterial or venous occlusion. MDCT findings were correlated with the surgical findings and clinical outcome. Patients were later divided into two groups: a study group of patients with proven AMI and a control group of patients with an alternate diagnosis, for the purpose of statistical analysis. AMI was correctly diagnosed in all 16 patients on MDCTA (100% sensitivity and specificity) of whom nine patients underwent surgical exploration. Three patients expired before surgery and the remaining 5 patients were proven based on positive clinical and laboratory findings. Mesenteric arterial occlusion was seen in 7 patients while 5 patients had portomesenteric venous thrombosis. Reconstructed images using minimum intensity projection, volume rendering and multiplanar volume reconstruction were found to perform better for the detection of vascular abnormalities and improved the diagnostic confidence of both radiologists in the evaluation of bowel and mesenteric abnormalities. MDCTA is an effective non-invasive modality for the diagnosis of mesenteric ischemia.

Cone-Beam Computed Tomography Study of Root and Canal Morphology of Maxillary First and Second Molars in an Indian Population

Introduction The aim of this study was to investigate the root and canal morphology of maxillary first and second molars in an Indian population by using cone-beam computed tomography (CBCT). Methods Maxillary first (n = 220) and second (n = 205) molars were collected from an indigenous Indian population and scanned by using a CBCT scanner at a constant slice thickness of 125 μm/slice. Volume rendering and multiplanar volume reconstruction were performed. The number of root canals was examined, and root canal system configurations were classified by using historical and contemporary classifications. Results Single-rooted first and second molars commonly showed types I, IV (0.5%) and type III (1%) canal systems, respectively. Buccal roots of two-rooted first molars showed 2 canal systems, type I and type IV, whereas second molars with 2 roots showed wide variations in canal anatomy. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (51.8% and 62%, respectively), followed by type IV (38.6% and 50%, respectively). The distobuccal and palatal roots of first and second molars showed predominantly type I canal morphology. Additional canal types were identified in 2.2% and 9.3% of the first and second molars, respectively. Conclusions The root number, morphology, and canal morphology of Indian maxillary molars showed features that were different from both Caucasian and Mongoloid traits. CBCT is an exciting and clinically useful tool in studying root canal morphology.

Assessment of Gastric Cancer: Value of Two-phase Multidetector-row Spiral CT Three-dimensional Reconstruction Technique

Objective: To evaluate the diagnostic value of two-phase multidetector-row spiral CT threedimensional reconstruction technique in TNM staging of gastric cancer. Methods: In 29 patients with gastric carcinoma pathologically conformed, plan scans were done firstly. Two-phase spiral CT was performed within one breathhold each. Distension of the stomach was achieved by intravenous application of anisodamine and effervescent granules. After bolus injection of contrast medium, scanning was performed in the arterial and venous phase, and the source images were thin reconstructed. The stomach to three-dimension analysis was constructed by volume rendering (VR) multiplanar volume reconstruction (MPVR), shaded surface display (SSD) and CT virtual gastroscopy (CTVG) technique. In combination with the sources images, gastric tumour invasion and lymph node metastasis was assessed, and TNM staging was performed. Results: In 29 cases of gastric carcinoma, the sensitivity and specificity of two-phase multidetector-row spiral CT three-dimensional reconstruction technique in T1, T2, T3 and T4 staging, the sensitivity and specificity was 50% and 50%, 87.5% and 77.8%, 83.3% and 76.9% and 100% and 80% respectively. For the N staging, the sensitivity and specificity in N0, N1, and N2-N3 was 83.3% and 71.4%, 87.5% and 77.8% and 81.8% and 75% respectively. The sensitivity and the specificity for M1 staging was 100%. Conclusion: The reconstruction technique in combination with 16-slices spiral-CT can perform TNM staging well and effectively guide the choice of the surgical procedures for gastric cancer.

Diagnostic value of 16 slices spiral-CT for portal vein disorders.

The diagnostic value of 16-slices spiral computed tomography (CT) for portal vein disorders was evaluated. Forty-one patients were scanned by the 16-slices spiral-CT. The celiac trunk, portal vein and their branches were reconstructed by volume rendering (VR), multiplanar volume reconstruction (MPVR) and maximum intensity projection (MIP) technique, and the results were compared with digital subtraction angiography (DSA). VR, MPVR and MIP could display celiac trunk, portal vein, inferior vena cava and their branches and extent of portal vein-vena cava shunt, portal vein emboli and the fistula of hepatic artery-portal vein. The results from 16-slices CT were better than DSA and identical with pathologic ones. The vessel three-dimension reconstruction technique of 16-slices spiral CT is valuable for evaluating the portal systemic disorders.

Carotid Artery Stenosis: Prospective Comparison of CT, Three-dimensional Gadolinium-enhanced MR, and Conventional Angiography

To prospectively compare gadolinium-enhanced magnetic resonance (MR) angiography and computed tomographic (CT) angiography with digital subtraction angiography (DSA) for use in detecting atheromatous stenosis and plaque morphology at the carotid bifurcation. Forty-four carotid arteries (in 22 patients) were analyzed by using CT angiography, enhanced MR angiography, and DSA. CT and enhanced MR angiograms were reconstructed with maximum intensity projection and multiplanar volume reconstruction. The following four features were analyzed: degree of stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial criteria, length of stenosis, luminal surface, and presence of ulcers. There was significant correlation between CT angiography, enhanced MR angiography, and DSA for degree and length of stenosis. With enhanced MR angiography and CT angiography, degree of stenosis was underestimated in two of 44 cases. No case of overestimation with CT angiography was found. Severe internal carotid artery stenoses were detected with high sensitivity and specificity: 100% and 100%, respectively, with CT angiography; 93% and 100%, respectively, with enhanced MR angiography. Luminal surface irregularities were most frequently seen at CT angiography. With CT angiography and enhanced MR angiography, more ulceration was detected than with DSA. There was a significant correlation between CT angiography, enhanced MR angiography, and DSA in evaluation of carotid artery stenosis. Enhanced MR angiography or CT angiography can be used to adequately evaluate carotid stenosis.

Telescoping bronchial anastomoses for unilateral or bilateral sequential lung transplantation: CT appearance.

To determine the computed tomographic (CT) appearance of telescoping bronchial anastomoses. CT scans obtained in 36 adult patients with 54 telescoping anastomoses (30 right bronchus, 24 left bronchus) were retrospectively reviewed. Seventeen scans were obtained with 10-mm collimation, one with 5-mm collimation, and 18 with 3-mm collimation. Multiplanar volume reconstruction images were retrospectively generated in 19 patients. CT findings were correlated with fiberoptic bronchoscopic findings and clinical records. Smooth, spherical air collections caused by diverticula of redundant mucosa were seen at the inferior or medial aspect of 22 anastomoses (41%). Endoluminal flaps and linear air collections caused by separation of the invaginated bronchus from the recipient bronchus were seen in 16 anastomoses (30%). Flaps and linear air collections were seen only at the anterior, superior, or inferior aspects of the anastomosis. Flaps and diverticula were more common at right anastomoses than at left anastomoses. No patient with an endoluminal flap or diverticulum at CT had dehiscence at bronchoscopy. Irregular air collections or posterior wall defects were suggestive of dehiscence at four anastomoses (7%). Dehiscence was confirmed bronchoscopically at two of these four anastomoses. Endoluminal flaps and linear or spherical air collections can be a normal feature of the telescoping anastomosis and should not necessarily be interpreted as dehiscence.

Spiral CT with reduced radiation dosage

To examine the clinical use of a reduced dose in high-resolution spiral-CT (HR-SCT) in combination with a multiplanar volume reconstruction technique (MPVR) to decrease image noise. Facial bones, skull and extremities of 33 patients with different pathological findings were examined with spiral-CT using a slice thickness of 1 mm (pitch 1.7-2.0), a tube amperage of 40 mA and tube voltages of 80 or 120 kV. Additionally, 2-D, 3-D, and MPVR images reconstructions were performed. MPVR takes advantage of displaying planar volumes of variable thickness. Increased image noise was negligible if high contrast structures like bones were examined. However, very small bony structures like the stapes of the middle ear were not seen. Soft tissues could also be imaged by using the MPVR-technique. This technique did reduce image noise while at the same time partial volume averaging was increased. The skin entrance dose per investigation did not exceed 3 mGy, which is based on twelve dose measurements in two patients. It is feasible to perform HR-SCT with secondary reconstructions of facial bones, skull and extremities using reduced skin entrance doses by 10 to 20 fold to below 3 mGy. With the exception of imaging very small structures, sufficient image quality can be accomplished in routine examinations without relevant diagnostic compromise.