Computed Tomography Software Research Articles

Method to Determine the Root Canal Anatomic Dimension by using a New Cone-Beam Computed Tomography Software.

This study discusses a method to determine the root canal anatomic dimension by using e-Vol DX software. The methodology consists in initially establishes the correct positions which will be measured, define the point on the edge of the anatomical structure, and next adjust the intermediate position in the grayscale of CBCT image. Afterward, thin sections (0.10 mm) are obtained from 3D reconstructed slices in the filter for the measurements, in order to determine the edge of the anatomical surface in the axial plane. A replication of positions in 3D mode is done in multiplanar reconstruction (MPR) of CBCT images, where the correct position is established with the aid of a positioning guide. The 3D density is adjusted so that it is in the same dimension as the 2D image, and a dimension calibration occurs to the point where there is a coincidence between 3D and 2D. This calibration is done only at the beginning of the measurement. Next, the intermediate position of the division between the grayscale is verified in the CBCT scan. Once one side has been completed, it is moved to the other side and follows the same guidelines described above. When setting the position of the courses in the other margin, being that 2D mode is used as reference. Thus, one obtains the required measure, being checked in the two points. The creation of this filter in the e-Vol DX software for measurement, and its appropriate management, allows more effective applications when it is desired to obtain diameters of anatomical structures.

Thrombectomy for Stroke at 6-24 hours without Perfusion CT Software for Patient Selection

Although, thrombectomy for stroke more than 6 hours after onset supported by automated perfusion computed tomography (CT) software (RAPID, iSchemaView) is effective, this software is not available in Japan. This study aimed to elucidate the efficacy of thrombectomy 6-24 hours after onset in our patient cohort using conventional imaging mismatch. Of 586 ischemic stroke patients who underwent thrombectomy registered from January 2015 to December 2017, patients with occlusion of the intracranial internal carotid artery or middle cerebral artery, who had last been known to be well 6-24 hours earlier and who had a prestroke modified Rankin scale (mRS) score 0 or 1 were enrolled. Clinical outcomes were the scores of the utility-weighted (UW) mRS, which ranges from 0 (death) to 10 (no symptom or disability), and the rate of functional independence (mRS score of 0-2) at 90 days. This study sample included 31 patients. The median baseline National Institutes of Health Stroke Scale score was 17 (interquartile range [IQR], 13-20), and the median Diffusion-Weighted Imaging-Alberta Stroke Program Early CT Score was 7 (IQR, 5-8). The median interval between the time that the patient was last known well and revascularization was 741 (IQR, 641-818) minutes. The mean UW mRS score at 90 days was 5.3, the rate of functional independence was 32%, and the 90-day mortality rate was 13%. Thrombectomy 6-24 hours after onset which can be performed with conventional imaging mismatch might be secured for improving functional independence in stroke patients.

Development of a New Cone-Beam Computed Tomography Software for Endodontic Diagnosis.

Cone-beam computed tomography (CBCT) has promoted changes in approaches in Endodontics, and enhanced decision-making in complex clinical cases. Despite the technological advancements in CBCT hardware, the interpretation of the acquired images is still compromised by viewing software packages that often have limited navigational tools and lack adequate filters to overcome some challenges of the CBCT technology such as artefacts. This study reviews the current limitations of CBCT and the potential of a new CBCT software package (e-Vol DX, CDT- Brazil) to overcome these aspects and support diagnosing, planning and managing of endodontic cases. This imaging method provide high resolution images due to submillimeter voxel sizes, dynamic multi-plane imaging navigation and ability to change the volume parameters such as slice thickness and slice intervals and data correction applying imaging filters and manipulating brightness and contrast. The main differences between e-Vol DX and other software packages are: compatibility with all current CBCT scanners with the capacity to export DICOM Data, a more comprehensive brightness and contrast library, as other applications, in which adjustments are limited, do not usually support all the DICOM dynamic range features; Custom slice thickness adjustment, often limited and pre-defined in other applications; Custom Sharpening adjustment, often limited in other applications; advanced noise reduction algorithm that enhances image quality; preset imaging filters, dedicated endodontic volume rendering filters with the ability to zoom the image over 1000x (3D reconstructions) without loss of resolution and automatic imaging parameters customization for better standardization and opportunities for research; capture screen resolution of 192 dpi, with a 384 dpi option, in contrast to the 96 dpi of most similar applications. This new CBCT software package may support decision-making for the treatment of complex endodontic cases and improve diagnosis and treatment results. Effective improvement of image quality favors the rational prescription and interpretation of CBCT scans.

Clinical utility of intraprocedural three‐dimensional integrated image guided transcatheter aortic valve implantation using novel automated computed tomography software: A single‐center preliminary experience

Novel automated computed tomography (CT) software (Valve ASSIST 2) has been developed for transcatheter aortic valve implantation (TAVI), which not only provides three-dimensional (3D) reconstruction of multidetector (MD) CT images, but also enables intraprocedural real-time fusion of fluoroscopic and MDCT images. We aimed to clarify the reproducibility and accuracy of this software in the aortic annulus assessment and verify the potential of intraprocedural integrated MDCT imaging for TAVI. We examined 50 patients with severe aortic stenosis undergoing transfemoral TAVI. Aortic annulus measurements were performed using 3mensio and the novel planning software. For intraprocedural imaging, preoperative CT dataset was overlaid onto fluoroscopy with the fusion software. The two images were aligned using the aortic root anatomy visible on both modalities. Novel planning software provided excellent reproducibility for the measurement of aortic annulus area (intraobserver intraclass correlation coefficients [ICC] 0.959, interobserver ICC 0.941), and perimeter (intraobserver ICC 0.915, interobserver ICC 0.912). Excellent correlation was found between novel planning software and 3mensio (ICC 0.952 for aortic annulus area, and 0.923 for perimeter). Intraprocedural fusion image of CT aortography and fluoroscopic aortic root aortography generated by this novel software identified coronary orifices and the distribution of aortic valve calcification during the device positioning. Fusion image displayed coronary orifices after device implantation. Novel planning software showed excellent reproducibility and accuracy in the assessment of aortic root anatomy. Furthermore, the integrated 3D fusion image might have a potential as an intraprocedural imaging modality to contribute to the development of a safer TAVI procedure.

Breathe New Life Into Your Chest CT Exams: Using Advanced Acquisition and Postprocessing Techniques

ObjectiveChest computed tomography (CT) imaging enables detailed visualization of the pulmonary structures and diseases. This article reviews how continued innovation and improvements in modern CT system hardware and software now facilitate a wider range of image acquisition options and generate unique qualitative and quantitative information that can benefit patients ResultsDual energy imaging utilizes two x-ray energies to highlight differences in tissue properties and increase iodine signal to improve diagnosis or reduce metal artifacts. Ultra-low dose imaging can be performed by using additional x-ray beam filtration, such as a tin filter, combined with iterative reconstruction algorithms to benefit lung cancer screening or pediatric imaging. Ultra-fast pitch spiral acquisition improves temporal resolution and reduces motion artifacts. Higher spatial resolution acquisition and reconstruction methods permit improved visualization of small structures. Radiomic analysis of chest CT image features permits risk stratification of pulmonary nodules and masses and reliable measures of change in pulmonary architecture and disease. ConclusionsMultiple new CT acquisition and reconstruction techniques, along with advanced post processing methods permit detailed analysis of changes in pulmonary architecture and function, and an expanded ability to adapt chest CT to the unique needs of different patients.

Effect of external fixation rod coupling in computed tomography

External fixation is a common tool in the treatment of complex fractures, correction of limb deformity, and salvage arthrodesis. These devices typically incorporate radio-opaque metal rods/struts connected at varying distances and orientations between rings. Whilst the predominant imaging modality is plain film radiology, computed tomography (CT) may be performed in order for the surgeon to make a more confident clinical decision (e.g. timing of frame removal, assessment of degree of arthrodesis). We used a fractured sheep leg to systematically assess CT imaging performance with a Discovery CT750 HD CT scanner (GE Healthcare) to show how rod coupling in both traditional Ilizarov and hexapod frames distorts images. We also investigated the role of dual-energy CT (DECT) and metal artefact reduction software (MARS) on the visualisation of the fractured leg. Whilst mechanical reasons predominantly dictate the rod/strut configurations when building a circular frame, rod coupling in CT can be minimised. Firstly, ideally, all or all but one rod can be removed during imaging resulting in no rod coupling. If this is not possible, strategies for configuring the rods to minimise the effect of the rod coupling on the region of interest are demonstrated, e.g., in the case of a four-rod construct, switching the two anterior rods to a more central single one will achieve this goal without particularly jeopardising mechanical strength for a short period. It is also shown that the addition of DECT and MARS results in a reduction of artefacts, but also affects tissue and bone differentiation.

Cardiac CT: Technological Advances in Hardware, Software, and Machine Learning Applications.

Multidetector row computed tomography (CT) allows noninvasive imaging of the heart and coronary arteries. The purpose of this review is to briefly summarize recent advances in CT hardware and software technology, and machine learning applications for cardiovascular imaging. In the last decades, there have been significant improvements in CT hardware focusing on faster gantry rotation resulting in improved temporal resolution. Concurrent hardware improvements include improved spatial resolution and higher coverage of the patient, enabling faster acquisition. Advances in cardiac CT software include methods for measurement of noninvasive FFR, coronary plaque characterization, and adipose tissue characteristics around the heart. Machine learning approaches using cardiac CT have been shown to improve both risk of prognosis and lesion-specific ischemia. Recent advances in CT hardware and software have expanded the clinical utility of CT for cardiovascular imaging. In the next decades, continued advances can be anticipated in these areas, and in machine learning applications in cardiac CT, as they are incorporated into clinical routine for image acquisition, image analysis, and prediction of patient outcomes.

Determining glenoid component version after total shoulder arthroplasty

Glenoid component loosening after total shoulder arthroplasty (TSA) may occur if retroversion is not corrected to <10°. However, accurately measuring postoperative glenoid component version has been difficult without postoperative computed tomography (CT), adding cost and radiation exposure outside of the standard radiographic follow-up. We present a new method to assess glenoid component version after TSA using only routine preoperative CT and postoperative radiographs (x-rays). Preoperative glenoid version was measured using established methods with an axillary x-ray, 2-dimensional CT, and Glenosys software (Imascap, Plouzané, France). Postoperative glenoid component version and inclination were measured for 61 TSA patients using Mimics software (Materialise, Leuven, Belgium) with preoperative CT and postoperative x-rays. Four patients also had postoperative CTs. Glenoid implantation and imaging were performed on 14 cadavers, allowing validation of results against the gold standard postoperative CT glenoid retroversion measurement. Compared with the gold standard, retroversion and inclination measurement error was 2° ± 1° and 2° ± 1°, respectively. Average postoperative version correction was 6° ± 7°, with 35 of 61 patients (57%) corrected to <10° of retroversion. Correlation between preoperative version measurement methods was good to very good, except on the axillary x-ray. Patients not corrected to <10° of retroversion had significantly higher preoperative retroversion (14° ± 6°) than those corrected to <10° (6° ± 7°; P < .00001). Glenoid component retroversion after TSA can be accurately measured with a method using only routine preoperative CT and postoperative x-rays, validated to within 1.9° of the gold standard postoperative CT measurement. Future studies using this method may correlate glenoid retroversion correction with glenoid component longevity to help optimize shoulder arthroplasty outcomes.

Nowoczesna tomografia komputerowa w diagnostyce wybranych wad wrodzonych żył płucnych

An excellent spatial and temporal resolution of computed tomography (CT) provides for precise evaluation of congenital cardiac malformation in selected group of patients. CT allows for quick, simultaneous assessment of all chest structures, such as pulmonary vessels, lung parenchyma and bones. Recent advances in CT hardware and software result in fast scanning of large anatomic ranges with a single lamp rotation without the need for patient's sedation and breath hold. The only limitation of CT is nowadays the exposure to ionizing radiation but with the new generation of scanners equipped with iterative reconstruction it is possible to reduce applied radiation dose while maintaining image quality. CT evaluation of pulmonary venous anomalies is well described, accurate for determining the site of anatomic obstruction in anomalous pulmonary venous return and has been shown to be highly specific when compared to operative findings. This article presents short review on current possibilities of CT diagnostic management of selected congenital pulmonary venous malformations.

Comparison of the Dixon and CTDI dose quantification techniques

Quantification of radiation dose in computed tomography(CT) is an ongoing area of research due to the continual evolution of CT technology both physical and software based. CT contributes to nearly 70% of the total dose given to patients during examinations [1] . As the number CT examinations are grown in the world, the radiation dose delivered from CT scanners to patient must be quantified precisely. Current dose measurement from CT is based on Computed Tomography Dose Index(CTDI) which was developed in 1981 [2] . The CTDI method utilizes a 10-cm long pencil ionization chamber placed in a 14-cm long PMMA phantom at 5 independent sites. The CT dose measurement is of a single rotation for each reference site. Modern CT scanners with helical scanning modes, auto exposure control, array detectors and multiple slice planes go beyond the efficacy of the CTDI technique. CTDI excludes the contribution of radiation scattered beyond the 100-mm range along the z axis. Dixon et al. [3] developed a new method to measure the dose from CT scan which is more accurate than the conventional CTDI. By scanning the length of a long phantom containing a small volume farmer chamber we were able to directly measure the cumulative dose D(x) at any point allowing the measurement of a dose equilibrium at the centre of the dose profile. This presentation will compare both techniques (i.e. the dose profiles and output obtained from Dixon and CTDI method in a Clinical CT.

Assessment of the primary stability of root analog zirconia implants designed using cone beam computed tomography software by means of the Periotest® device: An ex vivo study. A preliminary report.

The implant primary stability is a fundamental prerequisite for a success of osseointegration process which determines the prosthetic reconstruction time. The aim of the present study was to assess the quality and precision of modern conical bone computer tomography (CBCT) software in preparing root analog zirconia implants (RAZIs) by measuring its primary stability by means of the Periotest device. Thirteen pig jaws with proper erupted first premolar (P1) teeth were used in the study. The CBCT examination was conducted in the area of the P1 tooth in each mandible. The 3-dimensional (3D) view of each tooth was designed from CBCT scan. The created 3D images were used to prepare root analog zirconia implants milled from a medical-grade zirconia block by means of laboratory milling. The RAZIs and titanium implants were placed into an alveolar socket after the tooth had been removed. The primary stability of the teeth before their extraction (G1), RAZIs (G2) and titanium implants (G3) were checked by Periotest devices. The mean results in PTV were: 15.9, 3.35, 12.7 for G1, G2 and G3 group, respectively. RAZIs during immediate loading achieved a significantly higher primary stability (lower Periotest value) as compared to the teeth and implants. The modern CBCT device allows us to design a precise image of an extracted tooth for the purpose of manufacturing a root analog implant. The additional feature of the surgical protocol using RAZI is the possibility of avoiding the augmentation procedure, which reduces the whole cost of the treatment.

Perioperative psoas to lumbar vertebral index does not successfully predict amputation-free survival after lower extremity revascularization

BackgroundAccurate and convenient methods for assessing a patient's risk of postoperative morbidity and mortality comprise important tools in clinical decision-making. Whereas some aspects of the patient's fitness for surgery can be easily quantified, measurement of the patient's frailty is often difficult or time-consuming. Previous research in the context of multiple types of major surgical procedures has reported psoas-L4 vertebral index (PLVI) to be a useful predictor of postoperative morbidity and mortality. MethodsThis retrospective cohort study assessed the hypothesis that PLVI can predict amputation-free survival (AFS) in patients undergoing open or endovascular lower extremity revascularization. The records of all lower extremity revascularization patients with preoperative computed tomography arteriography before revascularization during a recent 6-year period were reviewed for demographic information and outcomes. With use of embedded computed tomography software, the cross-sectional area of the bilateral psoas muscles and vertebral body at the L4 level were measured and used to calculate the PLVI. Univariate, multivariate logistic regression, and Cox proportional hazards analyses were performed for the primary outcome of AFS. ResultsDuring a 6-year period, 188 patents had preoperative scanning, qualifying for inclusion in the study; 52% received open surgical bypass and 48% received a percutaneous endovascular procedure, with a median duration of follow-up of 12 months (interquartile range [IQR], 3-24 months). Median bilateral psoas cross-sectional area was 24.9 cm2 (IQR, 20.5-29.7 cm2), and mean PLVI was 1.74 (IQR, 1.39-2.05). Cox proportional hazards analysis identified age (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.01-1.14; P = .026), congestive heart failure (HR, 4.7; 95% CI, 1.29-16.9; P = .019), and dyslipidemia (HR, 0.34; 95% CI, 0.12-0.99; P = .049) as independent predictors of AFS loss, whereas PLVI was not (HR, 2.6; 95% CI, 0.83-8.39; P = .099). Kaplan-Meier life-table analysis demonstrated no significant differences in survival between the highest and lowest PLVI cohorts of patients. Hazard analysis showed concomitant congestive heart failure (HR, 15; 95% CI, 1.1-210; P = .042) and serum albumin concentration (HR, 0.16; 95% CI, 0.05-0.52; P = .0026) to be independent predictors of limb loss, whereas advanced age (HR, 1.20; 95% CI, 1.07-1.35; P = .0026), bypass procedure (HR, 4.6; 95% CI, 1.04-21; P = .045), non-African American race (HR, 9.09; 95% CI, 1.02-100; P = .048), and higher PLVI (HR, 10.9; 95% CI, 1.7-72; P = .013) predicted increased risk of mortality. ConclusionsPLVI did not predict AFS after intervention for peripheral arterial occlusive disease. This is contrary to the ability of PLVI to predict perioperative and midterm survival after abdominal aortic aneurysm repair and other major abdominal surgery.

P751Potential clinical utility of intraprocedural three-dimensional integrated image guided transcatheter aortic valve implantation using novel automated computed tomography software

P751Potential clinical utility of intraprocedural three-dimensional integrated image guided transcatheter aortic valve implantation using novel automated computed tomography software

Usefulness of three-dimensional image navigation system for evaluation of hepatic artery before living donor liver transplantation: a case report

BackgroundThe evaluation of the hepatic vascular anatomy in living liver donors is increasingly being performed by three-dimensional (3D) computed tomography (CT) angiography. However, details of hepatic artery anatomy obtained by 3D CT angiography are not always superior to those obtained by angiography. Here, we report a case in which the 3D image navigation system helped to detect segment II, III, and IV arteries (A2, A3, and A4, respectively) that individually originated from the proper hepatic artery (PHA); this could not be detected by 3D CT angiography.Case presentationA 46-year-old man with end-stage primary biliary cirrhosis was admitted to our hospital for evaluation as a candidate for living donor liver transplantation. The patient’s younger sister, aged 43 years, was the only living donor candidate. The predicted left liver graft volume with the middle hepatic vein was found to be 403 mL using the region-growing method with 3D CT software. This volume was sufficiently large for the recipient because the standard liver volume of the recipient was 1095 mL. 3D CT angiography was performed twice but could not reveal the anatomical structure of the left and middle hepatic arteries. However, simulation using the region-growing method demonstrated individual branching off of A2, A3, and A4 from the PHA; conventional angiography demonstrated the same results. Each branch was approximately 1 mm in diameter, which was too small for secure anastomosis. Therefore, we selected the right liver graft for simplicity. The postoperative course of the donor and recipient was uneventful, and they were discharged on postoperative days 10 and 46, respectively.ConclusionsIn conclusion, reconstruction of the hepatic vasculature using the 3D software by region-growing method might be a useful adjunct for surgical planning in the evaluation of the hepatic arteries in living liver donors.

Incomplete fissures are associated with increased alveolar ventilation via spiracles in severe emphysema.

In emphysema, air can flow preferentially via collateral pathways, which can connect an entire lung when incomplete fissures are present. Spiracles are openings through the chest wall into the lung parenchyma. We previously observed increased alveolar ventilation (VA) in subjects with severe emphysema, when spiracles occurred during lung transplant operations. In this study, we set out to identify a computed tomography (CT) imaging phenotype associated with improved VA via spiracles in severe emphysema. We retrospectively reviewed 4 patients with severe emphysema who exhaled ≥75% of the inhaled tidal volume via transpleural spiracles during a lung transplant operation. We used quantitative image analysis via VIDA VISION CT software to describe emphysema severity and distribution and fissure integrity from pretransplant CT scans of the chest. We analysed partial pressure of carbon dioxide and calculated estimates of VA at baseline and during spiracle ventilation. All 4 subjects demonstrated severe hyperinflation (total lung capacity 148 ± 24%predicted, residual volume 296 ± 79% predicted). On CT imaging, severe emphysema was present, with an average 38.7 ± 9% (range 28-50%) of lung parenchyma showing low-attenuation areas of - 950 Hounsfield units or less. Lung fissure integrity analysis demonstrated evidence of incomplete fissures (average detectable fissure integrity 67 ± 19%, range 40 ± 11-90 ± 10%). During spiracle ventilation on unchanged ventilator settings, there was a significant reduction in partial pressure of carbon dioxide (61 ± 4-35 ± 4 mmHg, P < 0.001) and increase in estimated VA (2.1 ± 0.5-3.8 ± 0.8 l/min, P < 0.001). Incomplete lung fissures on quantitative CT analysis seem to be a key image phenotype associated with substantial improvements in VA during transpleural ventilation via spiracles in severe emphysema.

Rectal gas volume: Defining cut-offs for screening for evacuation disorders in patients with constipation.

Diagnosis of rectal evacuation disorders (RED) is currently based on anorectal manometry (ARM) and evacuation tests in specialized laboratories; we recently showed higher rectal gas volume (RGV) and maximum rectal gas transaxial area (MRGTA) measured on abdominal and pelvic computed tomography (CT) in patients with documented RED.The aim of this study was to obtain cut-off values of RGV, MRGTA, and rectal area on scout film (RASF) to differentiate constipated patients with RED from those without RED, based on ARM, balloon expulsion test (BET), and colon transit test. We identified 118 constipated patients (65 with RED) with prior record of CT. Using standard CT software, we used a variable region of interest (ROI) program to measure RGV, MRTGA, and RASF, as previously described. We constructed receiver operating characteristics curves based on different values, and we estimated AUC, specificity, and positive predictive value (PPV) to detect RED in patients with constipation. Receiver operating characteristics of the models to predict RED showed AUC 0.751 for RGV and 0.737 for MRGTA (both P<.001), and 0.623 for RASF (P=.029). At specificity of 90%, RGV of 30mL had a PPV 77.3%, MRGTA of 10cm2 had a PPV 75.0%, and RFAS of 9cm2 had a PPV of 68.8% for identifying constipated patients with RED. Rectal gas measurements on abdominal imaging may indicate RED in patients with constipation. At ~90% specificity for RED, RGV of 20 or 30mL or MRGTA of 10cm2 on CT has PPV ~75%, and RASF of >9cm2 has PPV of ~69%.

Dual-energy CT with virtual monochromatic images and metal artifact reduction software for reducing metallic dental artifacts.

Background Metallic dental prostheses may degrade image quality on head and neck computed tomography (CT). However, there is little information available on the use of dual-energy CT (DECT) and metal artifact reduction software (MARS) in the head and neck regions to reduce metallic dental artifacts. Purpose To assess the usefulness of DECT with virtual monochromatic imaging and MARS to reduce metallic dental artifacts. Material and Methods DECT was performed using fast kilovoltage (kV)-switching between 80-kV and 140-kV in 20 patients with metallic dental prostheses. CT data were reconstructed with and without MARS, and with synthesized monochromatic energy in the range of 40-140-kiloelectron volt (keV). For quantitative analysis, the artifact index of the tongue, buccal, and parotid areas was calculated for each scan. For qualitative analysis, two radiologists evaluated 70-keV and 100-keV images with and without MARS for tongue, buccal, parotid areas, and metallic denture. The locations and characteristics of the MARS-related artifacts, if any, were also recorded. Results DECT with MARS markedly reduced metallic dental artifacts and improved image quality in the buccal area ( P < 0.001) and the tongue ( P < 0.001), but not in the parotid area. The margin and internal architecture of the metallic dentures were more clearly delineated with MARS ( P < 0.001) and in the higher-energy images than in the lower-energy images ( P = 0.042). MARS-related artifacts most commonly occurred in the deep center of the neck. Conclusion DECT with MARS can reduce metallic dental artifacts and improve delineation of the metallic prosthesis and periprosthetic region.

Volumetric assessment of alveolar clefts: a literature review.

To conduct a review of the literature on methods for volumetric assessment of alveolar clefts and ascertain which methods are most precise to guide future research. The PubMed and MEDLINE databases were searched for English-language reports of clinical and in vitro studies with detailed descriptions of imaging modality, sample characteristics, and method for measurement of alveolar cleft volume. The search strategy yielded 34 articles, of which 14 were selected for in-depth analysis. According to the findings of computed tomography (CT)-based studies, the CT modalities and software employed for assessment were deemed reliable and satisfactory. Measurement of alveolar cleft volume by the proposed methods and using the equipment and software employed in the analyzed studies has high efficacy and efficiency and can be safely used for cleft lip and palate treatment planning.

Study on the segmentation of the right anterior sector of the liver

The segmentation of the right anterior sector of the liver still is debatable due to the lack of an anatomic landmark of the boundary between Couinaud segments V and VIII (cranio-caudal segmentation). Some authors have proposed the concept of a ventro-dorsal segmentation. The aim of this study was to evaluate which concept of segmentation better reflects the anatomy. Using 3-dimensional computed tomography software, the ramification pattern of the right anterior portal vein was examined in 100 patients. A thick, hepatic, venous branch that passes throughCouinaud segment VIII was termed V8, and its course was investigated using a virtual hepatectomy. Regarding the anatomy of the portal vein in the right anterior sector, the cranio-caudal type was found in 53 patients, the ventro-dorsal type in 23 patients, and the trifurcation type in 13 patients. The remaining 11 patients had miscellaneous patterns of ramification. In the cranio-caudal type, the volume of the cranial segment was greater (P<.001) than that of the caudal segment. In the ventro-dorsal type, the volume of the ventral segment was greater (P=.007) than that of the dorsal segment. The V8 was identified in 81 of the 89 (91%) patients analyzed. The proportion of cases in which the V8 functionedas a landmark of the border between the ventral and dorsal segments was 63% (56/89 patients). Regarding the segmentation of the right anterior sector of the liver, the cranio-caudal segmentation introduced by Couinaud is dominant (53%), while ventro-dorsal segmentation is less common (23%). Therefore, universalization of the concept of the ventro-dorsal segmentation is unrealistic.

Comparison of canal transportation and centering ability of Twisted Files, HyFlex controlled memory, and Wave One using computed tomography scan: An in vitro study.

Aim:The aim of the present study was to compare the canal transportation and centering ability of three rotary nickel-titanium (NiTi) systems (Twisted Files [TF], HyFlex controlled memory [CM], and Wave One [WO]) in curved root canals using computed tomography (CT).Materials and Methods:Sixty freshly extracted single-rooted teeth having curved root canals with at least 25–35 degrees of curvature were selected. The teeth were randomly divided into three experimental groups of twenty each. After preparation with TF, HyFlex CM, and WO, all teeth were scanned using CT to determine the root canal shape. Pre- and post-instrumentation images were obtained at three levels, 3 mm apical, 9 mm middle, and 15 mm coronal above the apical foramen were compared using CT software. Amount of transportation and centering ability were assessed. The three groups were statistically compared with analysis of variance and post hoc Tukey's honestly significant difference test.Results:Least apical transportation and higher centering ability were seen in HyFlex CM file system in all the three sections followed by TF. WO file system showed maximum transportation.Conclusions:The canal preparation with HyFlex CM file system showed lesser transportation and better centering ability than TF, WO file system.