Specific Anatomical Information Research Articles

CNN-Based Segmentation and Detection of Brain Tumors MRI Images: A Review

In order to provide effective therapy and enhance patient outcomes, it is essential to diagnose brain tumors as early as possible and with high accuracy. Due to the fact that it provides very specific anatomical information, magnetic resonance imaging (MRI) is an extremely important tool for diagnosing brain tumors. The manual segmentation and identification of brain tumors from MRI images, on the other hand, would take a significant amount of time and are prone to human mistake. The use of convolutional neural networks, often known as CNNs, has become more popular as a resource for automating certain activities. The purpose of this review article is to investigate the current developments in CNN-based methods for the segmentation and identification of brain tumors in magnetic resonance imaging (MRI) images. We describe the most significant difficulties that are connected with the analysis of brain tumors using MRI, investigate the different CNN designs that are used for this purpose, and evaluate the performance metrics of these architectures. The purpose of this study is to offer a complete overview of the present state-of-the-art in CNN-based brain tumor analysis of MRI data, emphasizing both the promise and limits of this method.

Gastric hypomotility after adjunctive pulmonary vein and posterior wall isolation using cryoballoon in patients with atrial fibrillation: case control study

Abstract Background Pulmonary vein isolation (PVI) and concomitant electrical isolation of left atrial (LA) posterior wall (posterior wall box isolation [POBI]) using cryoballoon have mentioned as alternative ablation method for atrial fibrillation (AF). Gastric hypomotility (GH) is a possible complication of cryoballoon ablation (CBA); however, it remains unclear which factors are associated with GH during PVI plus POBI using cryoballoon. Objective We sought to investigate the clinical characteristics and intra-procedural parameters in AF patients with GH after PVI plus POBI using cryoballoon. Methods Forty-seven patients who underwent first-time CBA procedure for drug-refractory AF were enrolled. After the completion of ipsilateral superior and inferior PVI, cryoballoon was subsequently used to perform POBI; ablating in a segmental fashion for both superior and inferior portions of LA posterior wall. Intra-procedural luminal esophageal temperature (LET) monitoring, and postprocedural esophagogastroscopy within 72 hours were performed in all patients. In addition, intra-procedural parameters of CBA were comparatively evaluated between the patients with or without GH. Results Of overall enrolled patients (69.6 ± 9.6 years, 62% paroxysmal AF, CHA2DS2-VASc score 3.2 ± 1.7), GH were observed in 4 (8.6%) patients. Clinical characteristics were similar between the patients with and without GH, while the diameter of left inferior pulmonary vein ostium was significantly smaller in patients with GH compared with those without (15.0 ± 1.5mm vs. 18.8 ± 0.5mm; p=0.018). With regard to the intra-procedural parameters, minimum balloon temperatures at 30 seconds after CBA initiation during inferior portions of LA posterior wall, and minimum LET during POBI were significantly lower in patients with GH compared with those without (-43.3 ± 4.9°C vs. -37.2 ± 5.0°C; p=0.024, and 15.8 ± 1.0°C vs. 23.0 ± 6.0°C; p=0.022, respectively). The optimal cut-off values for prediction were -45°C (sensitivity 75%; specificity 92.5%), and 16.8°C (sensitivity 100%; specificity 85.4%), respectively. Conclusion Specific anatomical information and intra-procedural parameters aid identifying high-risk populations of GH after PVI plus POBI using cryoballoon.

Anatomy-guided multi-resolution image reconstruction in PET

Objective. In this paper, we propose positron emission tomography image reconstruction using a multi-resolution triangular mesh. The mesh can be adapted based on patient specific anatomical information that can be in the form of a computed tomography or magnetic resonance imaging image in the hybrid imaging systems. The triangular mesh can be adapted to high resolution in localized anatomical regions of interest (ROI) and made coarser in other regions, leading to an imaging model with high resolution in the ROI with clearly reduced number of degrees of freedom compared to a conventional uniformly dense imaging model. Approach. We compare maximum likelihood expectation maximization reconstructions with the multi-resolution model to reconstructions using a uniformly dense mesh, a sparse mesh and regular rectangular pixel mesh. Two simulated cases are used in the comparison, with the first one using the NEMA image quality phantom and the second the XCAT human phantom. Main results. When compared to the results with the uniform imaging models, the locally refined multi-resolution mesh retains the accuracy of the dense mesh reconstruction in the ROI while being faster to compute than the reconstructions with the uniformly dense mesh. The locally dense multi-resolution model leads also to more accurate reconstruction than the pixel-based mesh or the sparse triangular mesh. Significance. The findings suggest that triangular multi-resolution mesh, which can be made patient and application specific, is a potential alternative for pixel-based reconstruction.

Transition toward Technological Transformation: Challenges of Implementing Virtual Reality and Augmented Reality in the Health Sector

Abstract Background: Metaverse, the disruptive digital technology, has demonstrated significant effectiveness in the fields of preventive and cognitive therapy, diagnostics, surgical interventions and rehabilitation. Virtual Reality (VR), a part of Metaverse, integrates imaging data and input from users and deliver a 3D graphical output which can be visualised through a wearable headset. Augmented reality (AR) on the other hand, can control the presence of the user in the real world. Methodology: A review was undertaken of peer-reviewed literature on the emerging evidence on the applications of AR and VR in healthcare. Research studies carried out to identify effectiveness of AR and VR technologies were included. Result: AR & VR have been effective in rehabilitation of patients of Autism Spectrum Disorders and Mild Cognitive Impairment by improving motor skills, social skills and various cognitive indices like task learning and attention. In the surgical field, AR head mounted device (HMD) can provide three-dimensional, patient specific anatomic information during surgery. It minimises surgical complications and improves patient satisfaction. AR is of particular interest in complicated spinal surgeries and orthopaedic manoeuvres which require high level of surgical skill. AR has also been used successfully in different types of robotic surgeries as well. In several countries AR technology have been used in basic medical and advanced surgical training. Major challenges in implementing AR and VR in the field of health care persist in the domains of cyber security, ethical issues and cost effectiveness. Conclusion: VR and AR technology can maximise patient outcomes and rapidly develop satisfactory patient management in fields of cognitive research and surgical interventions. More clinical trials with immersive digital technologies are required. Ethical and cyber security challenges are present but there are ways to overcome them. It is our duty as physicians to participate in the development of these innovations to ensure virtual health reality benefits for our patients in real-world setting.

Augmented reality in the operating room: a clinical feasibility study

BackgroundAugmented Reality (AR) is a rapidly emerging technology finding growing acceptance and application in different fields of surgery. Various studies have been performed evaluating the precision and accuracy of AR guided navigation. This study investigates the feasibility of a commercially available AR head mounted device during orthopedic surgery.MethodsThirteen orthopedic surgeons from a Swiss university clinic performed 25 orthopedic surgical procedures wearing a holographic AR headset (HoloLens, Microsoft, Redmond, WA, USA) providing complementary three-dimensional, patient specific anatomic information. The surgeon’s experience of using the device during surgery was recorded using a standardized 58-item questionnaire grading different aspects on a 100-point scale with anchor statements.ResultsSurgeons were generally satisfied with image quality (85 ± 17 points) and accuracy of the virtual objects (84 ± 19 point). Wearing the AR device was rated as fairly comfortable (79 ± 13 points). Functionality of voice commands (68 ± 20 points) and gestures (66 ± 20 points) provided less favorable results. The greatest potential in the use of the AR device was found for surgical correction of deformities (87 ± 15 points). Overall, surgeons were satisfied with the application of this novel technology (78 ± 20 points) and future access to it was demanded (75 ± 22 points).ConclusionAR is a rapidly evolving technology with large potential in different surgical settings, offering the opportunity to provide a compact, low cost alternative requiring a minimum of infrastructure compared to conventional navigation systems. While surgeons where generally satisfied with image quality of the here tested head mounted AR device, some technical and ergonomic shortcomings were pointed out. This study serves as a proof of concept for the use of an AR head mounted device in a real-world sterile setting in orthopedic surgery.

The use of broad vs restricted regions of interest in functional near-infrared spectroscopy for measuring cortical activation to auditory-only and visual-only speech

As an alternative to fMRI, functional near-infrared spectroscopy (fNIRS) is a relatively new tool for observing cortical activation. However, spatial resolution is reduced compared to fMRI and often the exact locations of fNIRS optodes and specific anatomical information is not known. The aim of this study was to explore the location and range of specific regions of interest that are sensitive to detecting cortical activation using fNIRS in response to auditory- and visual-only connected speech.Two approaches to a priori region-of-interest selection were explored. First, broad regions corresponding to the auditory cortex and occipital lobe were analysed. Next, the fNIRS Optode Location Decider (fOLD) tool was used to divide the auditory and visual regions into two subregions corresponding to distinct anatomical structures. The Auditory-A and -B regions corresponded to Heschl's gyrus and planum temporale, respectively. The Visual-A region corresponded to the superior occipital gyrus and the cuneus, and the Visual-B region corresponded to the middle occipital gyrus. The experimental stimulus consisted of a connected speech signal segmented into 12.5-sec blocks and was presented in either an auditory-only or visual-only condition.Group-level results for eight normal-hearing adult participants averaged over the broad regions of interest revealed significant auditory-evoked activation for both the left and right broad auditory regions of interest. No significant activity was observed for any other broad region of interest in response to any stimulus condition. When divided into subregions, there was a significant positive auditory-evoked response in the left and right Auditory-A regions, suggesting activation near the primary auditory cortex in response to auditory-only speech. There was a significant positive visual-evoked response in the Visual-B region, suggesting middle occipital gyrus activation in response to visual-only speech. In the Visual-A region, however, there was a significant negative visual-evoked response. This result suggests a significant decrease in oxygenated hemoglobin in the superior occipital gyrus as well as the cuneus in response to visual-only speech. Distinct response characteristics, either positive or negative, in adjacent subregions within the temporal and occipital lobes were fairly consistent on the individual level.Results suggest that temporal regions near Heschl's gyrus may be the most advantageous location in adults for identifying hemodynamic responses to complex auditory speech signals using fNIRS. In the occipital lobe, regions corresponding to the facial processing pathway may prove advantageous for measuring positive responses to visual speech using fNIRS.

Lesson of the month 1: Spontaneous septic thrombophlebitis presenting with bacteraemia diagnosed by PET-CT scan

Spontaneous septic thrombophlebitis is a rare complication of Staphylococcus aureus bacteraemia. Its true incidence is unknown as septic thrombus is not often considered as a source in the typical 'screen' of tests used to find the source of a bacteraemia.Positron emission tomography computerised tomography (PET-CT) is becoming increasingly available to physicians, is highly sensitive and yields specific anatomical information regarding abnormal metabolically active sites in infection, inflammation and neoplasia.In this case, PET-CT enabled the identification of the source of a septic thrombus and enabled focused management. PET-CT should be considered as part of the raft of tests used to identify an obscure source of fever/bacteraemia.

Clinical application of a surgical navigation system based on virtual laparoscopy in laparoscopic gastrectomy for gastric cancer.

Knowledge of the specific anatomical information of a patient is important when planning and undertaking laparoscopic surgery due to the restricted field of view and lack of tactile feedback compared to open surgery. To assist this type of surgery, we have developed a surgical navigation system that presents the patient's anatomical information synchronized with the laparoscope position. This paper presents the surgical navigation system and its clinical application to laparoscopic gastrectomy for gastric cancer. The proposed surgical navigation system generates virtual laparoscopic views corresponding to the laparoscope position recorded with a three-dimensional (3D) positional tracker. The virtual laparoscopic views are generated from preoperative CT images. A point-based registration aligns coordinate systems between the patient's anatomy and image coordinates. The proposed navigation system is able to display the virtual laparoscopic views using the registration result during surgery. We performed surgical navigation during laparoscopic gastrectomy in 23 cases. The navigation system was able to present the virtual laparoscopic views in synchronization with the laparoscopic position. The fiducial registration error was calculated in all 23 cases, and the average was 14.0mm (range 6.1-29.8). The proposed surgical navigation system can provide CT-derived patient anatomy aligned to the laparoscopic view in real time during surgery. This system enables accurate identification of vascular anatomy as a guide to vessel clamping prior to total or partial gastrectomy.

Computed Tomography—Based Exploration of Infundibular Anatomy for Maxillary Sinus Balloon Dilation

A clinically relevant reconstruction of the ethmoid infundibulum and maxillary sinus ostium was developed to use 3-dimensional computed tomographic (CT) imaging technology and measurement software in an effort to better understand the anatomy of the maxillary sinus ostium and to optimize the maxillary sinus balloon dilation technique. A retrospective review was performed of reconstructed high-resolution CT scans of patients from a private otolaryngology practice who underwent imaging for evaluation of sinus disease using multiplanar reconstruction software. The CT scans were retrospectively obtained from patients who presented for evaluation of chronic sinus disease and were analyzed with quantitative multiplanar reconstruction software that allowed measurements to be computed in clinically meaningful planes. Data were obtained from 31 sinuses on 18 CT scans. The mean anteroposterior distance from the guidewire exit to the maxillary ostium was 3.5 mm, and the mean optimal guide trajectory ("clocking") angle was 17.50 from the pure axialplane (95% confidence interval, 12.58 degrees to 22.48 degrees). The curvilinear guidewire travel distance was 6.9 mm from the guidewire exit to the ostial entry. This study reveals specific anatomic information that is applicable to the technique of transnasal maxillary sinus balloon catheter dilation. The data collected allow surgeons to anticipate the direction in which a guidewire must be manipulated in order to correctly enter the maxillary ostium. According to the data, a gentle anterior retraction of the uncinate process and a starting guide orientation 180 from pure lateral will best facilitate maxillary sinus ostial access. Application of the readily available software used for this study affords the opportunity to predict the location of the natural ostium within the infundibulum before operation and customize the technique to each specific patient.

The respiratory down‐regulation debate

The respiratory down‐regulation debate

Localization of Intestinal Bleeding Using a Fusion of Tc-99m-Labeled RBC SPECT and X-ray CT

Although Tc-99m-labeled RBC SPECT is sensitive for detection of intestinal bleeding, it cannot provide a high degree of specific anatomic information. We present a case of intestinal bleeding in which a fused image composed of those from Tc-99m-labeled RBC SPECT and from x-ray CT revealed small intestinal bleeding with specific anatomic information. We believe that the fused image is useful for anatomic localization of gastrointestinal bleeding and helpful for surgical intervention.

Nerve Blocks in the Diagnosis of Low Back Pain

The use of diagnostic injection techniques in the evaluation of low back pain disorders is a clinical judgment skill, based on applied anatomy, pharmacology of the agents employed, and the neurophysiology of pain. In earlier years, the focus was primarily on the anatomic basis of pain, with sometimes oversimplistic interpretations of the results obtained. Although an anatomic correlation of a subjective complaint remains the same diagnostic objective today, a clearer understanding of pain concepts has also given these injection techniques a greater sensitivity but narrower spectrum in their application. Local anesthetic injections can readily identify sources of pain in soft tissues, scar tissue, nerve injury, and ligaments. They have particular application in this regard in postsurgical and postinjury back pain states in which the normal anatomy or function may be distorted. Local anesthetic blocks can also corroborate or define sites of pain in dorsal facet joints and in torsional disc capsule tears, where sites of multiple imaging or negative imaging findings make for difficult clinical diagnosis. In this context, they can also allow additional injection of deposteroid preparations, extending the procedure to a longer term therapeutic measure. Less specific anatomic information can be developed with respect to contributions from afferent and efferent responses, and in peripheral as compared with central mechanisms subserving the total clinical pain. For disorders of neuropathic and sensitization pain states, the spinal segmental level of signal processing from which conscious projection is derived can be well defined. Planned use of diagnostic blocking techniques is not a shortcut to sophisticated imaging or neurophysiologic studies but readily complements such investigations when conclusions are equivocal. Diagnostic blocks are only as good as the detailed clinical examinations which precede and follow the block itself.

Echocardiography in the neonate and young infant

The neonate and young child present unique problems in echocardiographic diagnosis because of the wide spectrum of possible abnormalities and the tendency toward multiple lesions, requiring clear visualization of all great veins and arteries as well as intracardiac structures. Performance and interpretation of echocardiograms in this age group require an extensive knowledge of the pathologic anatomy of congenital heart disease. Recognition of unusual lesions is facilitated by displaying the heart in an anatomically familiar (upright) format in order to draw from experience in angiography and pathology. The subxiphoid (subcostal) transducer position provides a flexible acoustic window for scanning the heart and great vessels in a multitude of planes, providing a general orientation for each cardiac segment. All other transducer positions are utilized to provide specific anatomic information. Although in this age group echocardiographic visualization of intracardiac anatomy is superior to other techniques, delineation of the great vessels remains its greatest limitation. Tortuous vessels may not lie in a single plane and, therefore, cannot always be displayed throughout its length by a "slice" technique such as echocardiography. In addition, limited focal range of most high frequency transducers is a continuing impediment to imaging structures in the posterior and superior mediastinum. Echocardiography provides a cost-effective means for identifying the neonate with life-threatening cardiovascular disease. It provides a complete and definitive anatomic diagnosis, in some cases eliminating the need for further procedures, while in others, improving the timing and performance of cardiac catheterization. Future studies should investigate the proper utilization of echocardiography as adjunct to or replacement of other techniques in the management of the young child.

Correlation of electrocardiographic studies and arteriographic findings with angina pectoris.

The relationships among angina pectoris, stress tests, and arteriography are complex. The majority of patients with angina pectoris can be adequately diagnosed by a careful history. Considerable attention to detail and repeated questioning is often necessary before the pain syndrome can be accurately classified. The resting electrocardiogram is of limited value in the diagnosis despite the fact that there is a high positive correlation between abnormal ST-T changes on the electrogram and significant obstructive lesions on coronary arteriograms. The value of the electrocardiogram is enhanced, and its specifiicity and sensitivity increased, when used in combination with exercise stress. The lowest error percentage is achieved by utilizing rate-standardized exercise tests and multiple leads with loads that produce heart rate responses of 80-90% of the expected maximum. Coronary arteriography gives the most specific anatomic information in patients with ischemic cardiac pain but will not directly disclose the cause of the pain. This fact assumes considerable importance when the pain has atypical features or when the patient is in the age group that has a high prevalence of coronary atherosclerosis. Similarly, the presence of past myocardial infarction is likely to be associated with obstructive disease, regardless of the cause of the patient's current symptoms. The exact role of lipid and other metabolic abnormalities in producing coronary arteriographic changes in the absence of symptoms needs further clarification, although the available data suggest that marked elevations in lipid fractions are frequently associated with atherosclerotic change, regardless of symptoms. Finally, the data imply that the anatomic abnormalities and functional consequences of the coronary atherosclerotic process are more important predictors of the patient's course than any specific symptomatic expression such as angina pectoris.