Prediction of carpal tunnel syndrome using the thenar muscle cross-sectional area by magnetic resonance imaging.

ABSTRACT: Carpal tunnel syndrome (CTS) is a common neuropathy. Although CTS progression is known to be associated with thenar muscle (TM) atrophy, the diagnostic value of TM atrophy for CTS has not been established. In this research, the thenar muscle cross-sectional area (TMCSA) was evaluated to analyze the relationship between the TMCSA and CTS. We assumed that TMCSA is a major diagnostic parameter in the CTS.Both TMCSA and thenar muscle thickness (TMT) samples were acquired from 18 CTS patients, and from 18 control subjects who underwent wrist magnetic resonance imaging with no evidence of CTS. T2-weighted transverse magnetic resonance imaging images were obtained. We measured the TMCSA and TMT at the level of first carpometacarpal joint.The average TMCSA was 296.98 ±â€Š49.39 mm2 in the normal group and 203.36 ±â€Š72.13 mm2 in the CTS group. The average TMT was 8.54 ±â€Š1.45 mm in the normal group and 7.38 ±â€Š1.14 mm in the CTS group. CTS group had significantly lower TMCSA and TMT. Receiver operator characteristics curve analysis showed that the best cutoff point for the TMCSA was 260.18 mm2, with 77.8% sensitivity, 77.8% specificity. The best cutoff point of the TMT was 7.70 mm, with 61.1% sensitivity, 66.7% specificity.Although the TMCSA and TMT were both significantly associated with CTS, the TMCSA was a much more sensitive measurement parameter. Thus, to evaluate CTS patients, the physician should more carefully inspect the TMCSA than TMT.

Variations in the Cross-Sectional Shape of the Apical Thirds of the Root Canals in Maxillary and Mandibular Teeth

Abstract Objective: To determine the prevalence of cross-sectional variations in the apical thirds of the root canals in maxillary and mandibular teeth. Material and Methods: Eighty tooth samples (maxillary second premolar, maxillary first molar, and mandibular first molar) were scanned using micro-computed tomography. The apical third area of each root canal was sectioned and the maximum and minimum diameters were calculated from the mesiodistal and buccolingual diameters. The shapes were categorized as a round, oval, long oval, and flat based on the ratios obtained. Results: The most common shape of the apical third of the root canals in the maxillary second premolars was oval (66.7%), followed by long oval (24.6%), flat (7%), and round (1.7%). The corresponding values in the mesiobuccal root of the maxillary first molars were oval (68.2%), long oval (22.7%), flat (9.1%), 94.1% of the distobuccal roots were oval, while the remaining were long oval (5.9%). All the palatal root canals were oval. In the mesiobuccal root of the mandibular first molars, 47.4% were long oval in shape, followed by 36.8% oval and 15.8% flat canals. All the mesiolingual root canals were oval, whereas, in the distal root, 68.4% were oval, 21.1% long oval, and 10.5% were flat. Conclusion: The oval shape was most commonly observed in the majority of the root canals. Knowledge about the apical anatomy of the root can help the operator improve the root canal treatment's success.

Impact of fetal brain ultrasound tutor smartphone application on normal anatomy learning.

OBJECTIVE: The "Fetal Brain Tutor 4us" (FBTApp) is a recently developed application for interactive multiplanar navigation through the normal fetal brain. The purpose of this work was to assess its impact on normal anatomy learning. METHODS: A multiple-choice quiz (MCQ) was administered to first-year resident doctors in Obstetrics and Gynecology in two separate sessions, before and 2 weeks after downloading the FBTApp. For each MCQ, the junior trainee was asked to use one out of five items to label a specific cerebral structure on an ultrasound image of a normal midtrimester fetal brain. Six sonographic images of the fetal brain on each of the three scanning planes (axial, sagittal, and coronal) were shown to the participants at either session. The results of the two sessions were analysed and compared. RESULTS: Overall, 216 questions were administered to the trainees in the 2-week study, 108 before and 108 after the use of the FBTApp. From the first to the second sessions, a significant increase of correct answers was noted (from 47/108 or 43% to 77/108 or 71%, P < 0.01). Particularly, a better improvement was obtained in the correct labelling of cerebral structures on the nonaxial (from 32% to 67%, +35%) vs axial (from 67% to 81%, +14%) view planes of the brain (P < 0.01). CONCLUSION: The use of FBTApp seems capable to improve the knowledge of the normal fetal brain anatomy in subjects naive to dedicated prenatal ultrasound. This improvement seems greater on nonaxial planes.

Horizontal Whole Mount: A Novel Processing and Imaging Protocol for Thick, Three-dimensional Tissue Cross-sections of Skin.

Processing a tissue of interest to generate a microscopic image that supports a scientific argument can be challenging. The acquisition of high-quality microscopic images is not entirely dependent upon the quality of the microscope, but also upon the methods of tissue processing, which often involve multiple critical actions or steps. Furthermore, mesenchymal cell types in the skin and other tissues represent a new challenge for tissue preparation and imaging. Here, we present a complete process, from tissue harvest to microscopy. Our technique, called "horizontal whole mount," is one that novices can quickly become proficient in and that allows for antigen preservation and detection in 60-300 µm-thick sections cut with a cryostat. Sections of this thickness provide enhanced visualization of tissue microarchitecture in a three-dimensional environment. In addition, the protocol preserves mesenchymal cells in a manner that enhances image quality when compared to standard cryostat or paraffin sections, thereby increasing the efficacy and reliability of immunostaining. We believe that this protocol will benefit all laboratories that visualize skin, and possibly other tissues and organs.

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Presurgical planning in implant restorations: correct interpretation of cone-beam computed tomography for improved imaging.

Contemporary implant dentistry is a primarily prosthetically driven treatment. The implant position is defined during the diagnostic phase, and the radiographic guide (template) indicates accurately the area of concern on the cone-beam computed tomography (CBCT). CBCT is an essential diagnostic key to a successful treatment plan in many cases. The aim of this paper was to underline the importance of proper alignment of the scanning levels in CBCT in order to avoid distorted cross-sectional images. As demonstrated with two clinical cases in this preliminary study, the initial scanning images of the CBCT must be drawn parallel to the occlusal plane, as defined by the diagnostic wax-up of the final restoration. The radiographic template offers valuable information about the planned location and inclination of the implant and the restoration. Proper image reconstruction following the dental scan can contribute significantly to accurate cross-sectional images and detailed presurgical planning.

Fast optically sectioned fluorescence HiLo endomicroscopy.

We describe a nonscanning, fiber bundle endomicroscope that performs optically sectioned fluorescence imaging with fast frame rates and real-time processing. Our sectioning technique is based on HiLo imaging, wherein two widefield images are acquired under uniform and structured illumination and numerically processed to reject out-of-focus background. This work is an improvement upon an earlier demonstration of widefield optical sectioning through a flexible fiber bundle. The improved device features lateral and axial resolutions of 2.6 and 17 µm, respectively, a net frame rate of 9.5 Hz obtained by real-time image processing with a graphics processing unit (GPU) and significantly reduced motion artifacts obtained by the use of a double-shutter camera. We demonstrate the performance of our system with optically sectioned images and videos of a fluorescently labeled chorioallantoic membrane (CAM) in the developing G. gallus embryo. HiLo endomicroscopy is a candidate technique for low-cost, high-speed clinical optical biopsies.

[The urological Dyna-CT. Urological cross-sectional imaging on a newly developed urological intervention table]. / Das urologische Dyna-CT. Urologische Schnittbildgebung auf einem neu entwickelten urologischen Interventionstisch.

BACKGROUND: The development of a new urological intervention table now enables the application of an Artis zee ceiling Dyna-CT (Siemens, Erlangen, Germany) for interventional cross-sectional imaging and 3-D reconstruction of the urinary tract in the prone and supine positions (urological Dyna-CT). MATERIALS AND METHODS: We tested the feasibility of the urological Dyna-CT with the newly developed urological intervention table. The system was moved five times to enable 3-D reconstruction of the urinary tract of a test person in the prone and in supine positions. RESULTS: Handling of the free floating table is easily possible during the intervention. We found no limitation of imaging system movement in any position of the test person. CONCLUSION: Apart from standard urological imaging such as fluoroscopy, intravenous pyelography or plain abdominal X-ray the urological Dyna-CT enables further imaging of the urinary tract. Fluoroscopy sequences can be stored as videos, and 3-D reconstructions of the urinary tract are possible with permanent patient access for any intervention. Extensive tests led to the technical approval of the system in urology.

Oblique sectional planes of block plastinates eased by Sac Plastination.

To find an oblique cutting plane of a plastinate, e.g. to cut gamma-nails in the femur, the Block Plastination technique was modified. After CT and MRI examination, the specimens were plastinated with the standard resin mixture E6/E12/E600. Instead of using a box to form a block during the casting and curing stage, we embedded the specimen in a sac made of polyester foil. A polymerized wooden block was attached to the specimen. The sac was wrapped with tape to the embedded specimen with the block. This approach limited the amount of required resin to the inner volume of the plastinate. Then, the plastination sac was put in the incubator for further polymerization and curing. When the foil was removed from the plastinated specimen, the wooden block served as a socket for the grip when sawing. The outer shape of the specimen remained visible. Doing so, the adequate cutting plane could be determined easily.

Modelo de contorno ativo crisp: nova técnica de segmentação dos pulmões em imagens de TC / Active contour modes crisp: new technique for segmentation the lungs in CT images

Este trabalho propõe um novo método de contornos ativos (MCA), chamado de MCA Crisp, e o avalia na segmentação dos pulmões em imagens de Tomografia Computadorizada (TC). O MCA consiste em traçar uma curva inicial em torno ou dentro de um objeto de interesse. Esta curva se deforma, conforme algumas energias que atuam sobre a mesma, deslocando-a até as bordas do objeto. Este processo é realizado por iterações sucessivas de minimização de uma dada energia, associada à curva. Aplicando MCAs descritos na literatura na segmentação dos pulmões em imagens de TC, constatam-se limitações. Neste contexto, propõe‑-se o MCA Crisp para suprir tais limitações, propondo uma inicialização automática e uma nova energia externa baseada em regras e nas densidades radiológicas pulmonares. Realiza-se uma comparação entre os MCAs Tradicional, Balão, GVF e o método proposto para demonstrar a superioridade do novo método. Em seguida, para validar o MCA Crisp realiza-se uma análise qualitativa junto a um médico especialista na área de Pneumologia do Hospital Universitário Walter Cantídio da Universidade Federal do Ceará. Nesta análise, são utilizados 100  pulmões em imagens de TC. A eficiência da segmentação foi avaliada em  5 categorias, obtendo os seguintes resultados:   73% ótimas, sem falhas, 20% aceitáveis, com pequenos erros, 7% razoáveis, com erros grosseiros e  0% ruim, segmentando apenas uma pequena parte do pulmão, e  0% péssima, obtendo uma segmentação totalmente errada. Conclui-se que o MCA Crisp é um método útil para segmentar os pulmões em imagens de TC e com potencial para integrar sistemas que auxiliem o diagnóstico médico.

This paper proposes a new Active Contour Model (ACM), called ACM Crisp, and evaluates the segmentation of lungs in computed tomography (CT) images. An ACM draws a curve around or within the object of interest. This curve changes its shape, when some energy acts on it and moves towards the edges of the object. This process is performed by successive iterations of minimization of a given energy, associated with the curve. The ACMs described in the literature have limitations when used for segmentations of CT lung images. The ACM Crisp model overcomes these limitations, since it proposes automatic initiation and new external energy based on rules and radiological pulmonary densities. The paper compares other ACMs with the proposed method, which is shown to be superior. In order to validate the algorithm a medical expert in the field of Pulmonology of the Walter Cantídio University Hospital from the Federal University of Ceará carried out a qualitative analysis. In these analyses  100 CT lung images were used. The segmentation efficiency was evaluated into  5 categories with the following results for the ACM Crisp: 73% excellent, without errors, 20% acceptable, with small errors, and  7% reasonable, with large errors, 0% poor, covering only a small part of the lung, and  0% very bad, making a totally incorrect segmentation. In conclusion the ACM Crisp is considered a useful algorithm to segment CT lung images, and with potential to integrate medical diagnosis systems.

Comparison of cross-sectional anatomy and computed tomography of the tarsus in horses.

OBJECTIVE: To compare computed tomography (CT) images of equine tarsi with cross-sectional anatomic slices and evaluate the potential of CT for imaging pathological tarsal changes in horses. SAMPLE: 6 anatomically normal equine cadaveric hind limbs and 4 tarsi with pathological changes. PROCEDURES: Precontrast CT was performed on 3 equine tarsi; sagittal and dorsal reconstructions were made. In all limbs, postcontrast CT was performed after intra-articular contrast medium injection of the tarsocrural, centrodistal, and tarsometatarsal joints. Images were matched with corresponding anatomic slices. Four tarsi with pathological changes underwent CT examination. RESULTS: The tibia, talus, calcaneus, and central, fused first and second, third, and fourth tarsal bones were clearly visualized as well as the long digital extensor, superficial digital flexor, lateral digital flexor (with tarsal flexor retinaculum), gastrocnemius, peroneus tertius, and tibialis cranialis tendons and the long plantar ligament. The lateral digital extensor, medial digital flexor, split peroneus tertius, and tibialis cranialis tendons and collateral ligaments could be located but not always clearly identified. Some small tarsal ligaments were identifiable, including plantar, medial, interosseus, and lateral talocalcaneal ligaments; interosseus talocentral, centrodistal, and tarsometatarsal ligaments; proximal and distal plantar ligaments; and talometatarsal ligament. Parts of the articular cartilage could be assessed on postcontrast images. Lesions were detected in the 4 tarsi with pathological changes. CONCLUSIONS AND CLINICAL RELEVANCE: CT of the tarsus is recommended when radiography and ultrasonography are inconclusive and during preoperative planning for treatment of complex fractures. Images from this study can serve as a CT reference, and CT of pathological changes was useful.

Minimum-intensity projection for in-depth morphology study of mesiobuccal root.

OBJECTIVE: This micro-computed tomography (MCT) study investigated the utility of thin-slab minimum-intensity projection (TS-MinIP) technique as an adjunct to 3-dimensional (3D) modeling for in-depth morphology study. STUDY DESIGN: One hundred one extracted maxillary first molars were scanned for microtomographic analysis (SkyScan). Two-dimensional TS-MinIP and 3D images of mesiobuccal (MB) roots were produced and analyzed to record the number and configurations of the canals, the incidence and location of accessory canals, loop, and intercanal connections, and number of foramina. RESULTS: Multiple-canal MB roots were present in 76.2%, and all of the roots had intercanal communications. Weine type III configuration was the most common in the multiple-canal roots. Accessory canals were found in 78.2% of the roots. Configurations that were nonclassifiable were found in 10.9% of the MB roots. CONCLUSIONS: MB root canal anatomy was complex, and MinIP may serve as an adjunct to 3D modeling for in-depth morphology study.

Ultrasound method for estimating the cross-sectional area of the psoas major muscle.

PURPOSE: The present study aimed to develop an ultrasonographic method for estimating the cross-sectional area of the psoas major muscle. METHODS: The muscle cross-sectional area (CSA(MRI)) and thickness (MT(MRI)) of the psoas major muscle at L4-L5 on the right and left sides of the body were measured using magnetic resonance imaging in 11 healthy sedentary men age 21 to 25 yr. Ultrasonographic images were obtained at the corresponding sites where CSA(MRI) and MT(MRI) measurements were performed. From the ultrasonographic images, the thickness of the psoas major muscle (MT(US)) was analyzed on both sides of the body. RESULTS: The interclass correlation coefficient of MT(US) measurements performed on two separated days was 0.951 for the right side and 0.971 for the left side. CSA(MRI) was significantly correlated to MT(MRI) (r = 0.934 for the right side and r = 0.910 for the left side). There was no significant difference between MT(MRI) (4.68 ± 0.39 cm for the right side and 4.73 ± 0.39 cm for the left side) and MT(US) (4.67 ± 0.40 cm for the right side and 4.72 ± 0.43 cm for the left side). The MT(US) was significantly correlated to MT(MRI) (r = 0.979 for the right side and r = 0.980 for the left side) and CSA(MRI) (r = 0.947 for the right side and r = 0.916 for the left side). CONCLUSION: The current results indicate that the psoas major muscle thickness determined by the ultrasonographic method is useful for estimating the cross-sectional area of the psoas major muscle.

A simple and efficient device for demonstrating cross-sectional anatomy of the head.

Described in this article is a novel device that facilitates study of the cross-sectional anatomy of the human head. In designing our device, we aimed to protect sections of the head from the destructive action of handling during anatomy laboratory while also ensuring excellent visualization of the anatomic structures. We used an electric saw to create 15-mm sections of three cadaver heads in the three traditional anatomic planes and inserted each section into a thin, perforated display box made of transparent acrylic material. The thin display boxes with head sections are kept in anatomical order in a larger transparent acrylic storage box containing formaldehyde solution, which preserves the specimens but also permits direct observation of the structures and their anatomic relationships to each other. This box-within-box design allows students to easily view sections of a head in its anatomical position as well as to examine internal structures by manipulating individual display boxes without altering the integrity of the preparations. This methodology for demonstrating cross-section anatomy allows efficient use of cadaveric material and technician time while also giving learners the best possible handling and visualization of complex anatomic structures. Our approach to teaching cross-sectional anatomy of the head can be applied to any part of human body, and the value of our device design will only increase as more complicated understandings of cross-sectional anatomy are required by advances and proliferation of imaging technology.

Virtual human dissector as a learning tool for studying cross-sectional anatomy.

BACKGROUND: Within diagnostic medicine there is a continuing and marked increase in the use of two-dimensional (2D) images of cross-sectional anatomy. Medical undergraduates should therefore develop skills to interpret such images early in their education. The Virtual Human Dissector (VHD) software facilitates such learning, permitting users to study actual images of 2D anatomical cross-sections and reconstructed three-dimensional (3D) views simultaneously. This study investigates the use of VHD in facilitating students' ability to interpret cross-sectional images and understand the relationships between anatomical structures. METHODS: First year medical students (n=89) were randomly divided into two groups. Using a crossover design, the investigation was undertaken as two 20 minute self-directed learning (SDL) activities using VHD in a computer suite and prosections and models in the dissecting room (DR), interspersed between 3 tests identifying anatomical structures in cross-sectional images (pre-, mid- and post-session). RESULTS: Statistical analysis of test performance revealed significant improvements in each group between the pre- and midsession tests, and again between mid- and post-session tests. There was no significant difference between the two groups at any stage. SDL using the VHD was as effective as SDL using prosections.

Resolution in the ApoTome and the confocal laser scanning microscope: comparison.

The essential feature of the confocal laser scanning microscope (cLSM) is the generation of optical sections by the removal of out-of-focus light. About ten years ago, structured illumination microscopy (SIM) was introduced as an alternative method for obtaining optical sections from biological specimens. Here we compare the resolution of the ApoTome (commercial SIM by Zeiss) to that achieved by a cLSM (Zeiss LSM 510). If fluorescent beads are used as test objects, then the ApoTome will achieve a lower axial resolution than the cLSM. In contrast to that, its lateral resolution scores slightly better. If subresolution homogeneous fluorescent layers are used as test objects, then the ApoTome will achieve a higher axial resolution than the cLSM. The ApoTome's axial resolution is homogeneous over the field-of-view while that of the cLSM changes markedly. Finally, the anisotropy of the ApoTome's resolution was found to be negligible for standard applications while its capability to resolve fine structures within stained tissue slices is limited to one or two cell layers and thus worse than in the cLSM.

Evaluation of voxel values in mandibular cancellous bone: relationship between cone-beam computed tomography and multislice helical computed tomography.

OBJECTIVE: Measurements of bone density in designed sites are important in presurgical imaging for dental implant treatment. However, the pixel or voxel values obtained from cone-beam computed tomography (CT) images are not absolute values. Hence, the relationship between voxel values obtained from cone-beam CT with a limited-volume exposure field and a flat panel detector and bone mineral densities (BMDs) obtained from multislice CT was evaluated in the mandible. MATERIAL AND METHODS: A total of 16 (four males and 12 females) patients who had undergone imaging for mandibular dental implant treatment using cone-beam CT with Alphard VEGA and multislice CT were enrolled in this investigation. Cross-sectional images of cone-beam and multislice CT were reconstructed, and values of regions of interest (ROIs) in images were calculated. RESULTS: A high-level correlation between voxel values of cone-beam CT and BMDs of multislice CT was observed (r=0.965). CONCLUSION: It was suggested that voxel values of mandibular cancellous bone in cone-beam CT could be used to estimate bone density.

Tomographic imaging of macroscopic biomedical objects in high resolution and three dimensions using orthogonal-plane fluorescence optical sectioning.

A new optical-fluorescence microscopy technique, called HR-OPFOS, is discussed and situated among similar OPFOS-implementations. OPFOS stands for orthogonal-plane fluorescence optical sectioning and thus is categorized as a laser light sheet based fluorescence microscopy method. HR-OPFOS is used to make tomographic recordings of macroscopic biomedical specimens in high resolution. It delivers cross sections through the object under study with semi-histological detail, which can be used to create three-dimensional computer models for finite-element modeling or anatomical studies. The general innovation of this class of microscopy setup consists of the separation of the illumination and observation axes, but now in our setup combined with focal line scanning to improve sectioning resolution. HR-OPFOS is demonstrated on gerbil hearing organs and on mouse and bird brains. The necessary specimen preparation is discussed.

Dimensional error of selective laser sintering, three-dimensional printing and PolyJet models in the reproduction of mandibular anatomy.

BACKGROUND: Selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet are rapid prototyping (RP) techniques to fabricate prototypes from virtual biomedical images. To be used in maxillofacial surgery, these models must accurately reproduce the craniofacial skeleton. PURPOSE: To analyze the capacity of SLS, 3DP and PolyJet models to reproduce mandibular anatomy and their dimensional error. MATERIAL: Dry mandible, helical CT images, SLS, 3DP and PolyJet prototypes, and digital electronic caliper. METHODS: Helical CT images were acquired from a dry mandible (criterion standard) and manipulated with the InVesalius software. Prototypes were produced using SLS, 3DP and PolyJet techniques. Thirteen linear measurements of each prototype were made and compared with the dry mandible measurements. RESULTS: The results showed a dimensional error of 1.79%, 3.14% and 2.14% for SLS, 3DP and PolyJet models, respectively. The models satisfactorily reproduced anatomic details and the SLS and PolyJet prototypes showed greater dimensional precision and reproduced mandibular anatomy more accurately than the 3DP model. CONCLUSIONS: The SLS prototype had a greater dimensional accuracy than the PolyJet and 3DP models. The PolyJet technique reproduced anatomic details of the mandible more accurately.