Anatomical Variations Research Articles

Right Atrial Septal InSitu Microthrombus: A Potential Novel Cause of Patent Foramen Ovale-Associated Stroke.

Patent foramen ovale (PFO)-associated stroke has a complex and diverse pathogenesis. It mainly results from a paradoxical embolism caused by venous thrombosis. However, few studies have investigated the presence of an insitu thrombus in the right atrium. Transesophageal echocardiography can effectively detect right atrial septal insitu microthrombus. Therefore, we aimed to explore the relationship between a right atrial septal insitu microthrombus and PFO-associated stroke and further dissect the pathophysiological basis of microthrombus formation. Between April 2022 and October 2023, we prospectively investigated 466 patients who visited our hospital for transesophageal echocardiography with a high clinical suspicion of PFO. Right atrial septal insitu microthrombus was detected in 34 patients (7%), and 23 of them were examined. The microthrombus disappeared in 13 patients and decreased in 7; PFO recanalization and anatomical variations were observed in 2 and 1 patient, respectively. The incidence of index stroke was higher in the microthrombus group than in the nonmicrothrombus group (76.47% versus 61.11%). Univariate and multivariable (adjusted) analyses revealed PFO as an independent risk factor for right atrial septal insitu microthrombus formation (odds ratio, 3.29 [95% CI, 1.49-7.26]; P=0.003). Transesophageal echocardiography effectively detects right atrial septal insitu microthrombus. A PFO may promote the formation of right atrial septal insitu microthrombus. Right atrial septal insitu microthrombus significantly increases the risk of PFO-associated stroke. This finding may be crucial in disease management strategies for patients with PFO.

Added value of pre-procedural magnetic resonance angiography in transarterial embolization for refractory musculoskeletal pain

BackgroundTransarterial microembolization (TAME) is a minimally invasive treatment for chronic musculoskeletal disorders. Identifying angiogenesis and the supplying vessels of the target joint is important but challenging. Although magnetic resonance imaging (MRI) is commonly used to diagnose musculoskeletal diseases, it typically excludes vascular imaging. Dynamic contrast-enhanced magnetic resonance angiography (DCE-MRA) has the ability to visualize lesion angiogenesis, identify supplying vessels, and evaluate the vasculature anatomy. We propose that incorporating DCE-MRA into pre-procedural assessments can help identify the culprit vessels, arterial anatomy, and variant assessment of the target joint before TAME.Materials and methodsWe investigated six cases, each presenting pain in different body parts: shoulder adhesive capsulitis, trapezius myalgia, combined tennis and golf elbow, knee osteoarthritis, refractory knee pain after osteotomy, and plantar fasciitis. All patients underwent MRI with DCE-MRA before undergoing TAME. DCE-MRA was performed using either 1.5 T or 3 T MRI scanners, employing 3D-TRICKS or 4D-TRAK XD techniques. The numerical rating scale for pain was evaluated at one, three, and six months after the procedure, and any adverse events were recorded over the entire six-month follow-up period.ResultsPre-procedural DCE-MRA helped to visualize angiogenesis at the lesion site in all patients and identify the supplying vessels, arterial vasculature anatomy, and branching variants. These findings corroborated the subsequent digital subtraction angiography (DSA) findings obtained during TAME. All patients experienced pain reduction and functional improvement after TAME without any complications. The average pain score reduced significantly after TAME treatment (p < 0.05). Two patients underwent a second MRI and DCE-MRA at the six-month follow-up and showed a significant reduction in angiogenesis.ConclusionDCE-MRA offers a valuable pre-procedural assessment tool for TAME procedures by facilitating the visualization of angiogenesis at the lesion site, supplying vessels, and arterial anatomic variants, including the variable orifice of the supplying branches. This information can potentially improve patient selection and pre-procedural planning, leading to better outcomes and reduced risk of complications.

Bioelastic state recovery for haptic sensory substitution.

The rich set of mechanoreceptors found in human skin1,2 offers a versatile engineering interface for transmitting information and eliciting perceptions3,4, potentially serving a broad range of applications in patient care5 and other important industries6,7. Targeted multisensory engagement of these afferent units, however, faces persistent challenges, especially for wearable, programmable systems that need to operate adaptively across the body8-11. Here we present a miniaturized electromechanical structure that, when combined with skin as an elastic, energy-storing element, supports bistable, self-sensing modes of deformation. Targeting specific classes of mechanoreceptors as the basis for distinct, programmed sensory responses, this haptic unit can deliver both dynamic and static stimuli, directed as either normal or shear forces. Systematic experimental and theoretical studies establish foundational principles and practical criteria for low-energy operation across natural anatomical variations in the mechanical properties of human skin. A wireless, skin-conformable haptic interface, integrating an array of these bistable transducers, serves as a high-density channel capable of rendering input from smartphone-based 3D scanning and inertial sensors. Demonstrations of this system include sensory substitution designed to improve the quality of life for patients with visual and proprioceptive impairments.

Virtual Reality for Preprocedure Planning of Covered Stent Correction of Superior Sinus Venosus Atrial Septal Defects.

Covered stent correction (CSC) of a superior sinus venosus atrial septal defect is an alternative to surgery in selected patients, but anatomic variation means that assessment for CSC requires a 3-dimensional anatomic understanding. Heart VR is a virtual reality (VR) system that rapidly displays and renders multimodality imaging without prior image segmentation. The aim of this study was to evaluate the performance of the Heart VR system to assess patient suitability for CSC. In a blinded fashion, 2 interventionalists reviewed preprocedural computed tomography scans using Heart VR to assess the feasibility of CSC, including the potential need for pulmonary vein protection. The total review time using VR was recorded. Using conventional imaging, 15 patients were deemed suitable for CSC, but at catheterization, 3 cases were unsuitable. Using VR, when both interventionalists agreed that a case was suitable for CSC (n=12), all proved technically feasible. In the 3 cases that were unsuitable for CSC, the interventionalists using VR were either uncertain (n=1) or did not agree on suitability (n=2). The strategy for pulmonary vein protection was correctly identified by interventionalist 1 and 2 in 9/12 and 8/12 cases, respectively. In cases where pulmonary vein protection was required intraprocedurally (n=5), this was correctly identified using Heart VR. Using VR, in 3 cases it was determined that pulmonary vein protection would be required, but this was not the case on balloon interrogation. VR data loading and review times were 82 seconds and 7 minutes, respectively. Verbal feedback indicated that Heart VR assisted in the assessment of case suitability. Heart VR is a rapid and effective tool for predicting suitability for CSC in patients with a superior sinus venosus atrial septal defect and could be a feasible alternative to segmented virtual or physical 3-dimensional models.

Prevalence and characteristics of facial nerve bifurcation in the mastoid segment: a retrospective analysis using temporal bone CT scans.

To investigate the prevalence and characteristics of bifurcation of the facial nerve (FN) in the mastoid segment using temporal bone CT scans. A total of 970 cases (1931 ears) of temporal bone CT scans were reviewed, including 463 females and 498 males, aged 1 to 95years (interquartile range: 20-69years). CT imaging with multiplanar reconstruction (MPR) was used to identify and evaluate the bifurcation of the FN. Cases showing branching were confirmed by consensus among three physicians. We identified 10 cases (10 ears) with facial nerve branching in the vertical segment, yielding an incidence rate of 0.52% (10/1931 ears). Every cases were unilateral, predominantly on the left side. Age analysis revealed 1 case (0.22%) in individuals under 20years and 9 cases (0.61%) in those over 20years. Bifurcation generally occurred near the middle to lower vertical segment, with the closest proximity to the second genu observed in a 15-year-old patient. Bifurcation of the FN in the mastoid segment, though rare, can be encountered in otologic surgery. Detailed preoperative imaging evaluations are crucial for surgical planning to minimize the risk of nerve damage. Our findings emphasize the importance of recognizing anatomical variations in the FN for improving surgical outcomes and patient safety.

Anatomical variations in 3D imaging: a case report of a dorsal metacarpal artery anomaly

Anatomical variations in 3D imaging: a case report of a dorsal metacarpal artery anomaly

Nanoceria-induced variations in leaf anatomy and cell wall composition drive the increase in mesophyll conductance of salt-stressed cotton leaves

Nanomaterials as an emerging tool are being used to improve plant′s net photosynthetic rate (AN) when suffering salt stress, but the underlying mechanisms remain unclear. To clarify this, a hydroponic experiment was conducted to study the effects of polyacrylic acid coated nanoceria (PNC) on the AN of salt-stressed cotton and related intrinsic mechanisms. Results showed that the PNC-induced AN enhancement of salt-stressed leaves was strongly facilitated by the mesophyll conductance to CO2 (gm). Further analysis showed that the PNC-induced improvement of gm was related to the increased chloroplast surface area exposed to intercellular airspaces, which was attribute to the increased mesophyll surface area exposed to intercellular airspaces and chloroplast number due to the increased K+ content and decreased reactive oxygen species level in salt-stressed leaves. Interestingly, our results also showed that PNC-induced variations in cell wall composition of salt-stressed cotton leaves strongly influenced gm, especially, hemicellulose and pectin. Moreover, the proportion of pectin in cell wall composition played a more important role in determining gm. Our study demonstrated for the first time that nanoceria, through alterations to anatomical traits and cell wall composition, drove gm enhancement, which ultimately increased AN of salt-stressed leaves.

Population-based in silico modeling of anatomical shape variation of the knee and its impact on joint loading in knee osteoarthritis.

Anatomical knee joint features and osteoarthritis (OA) severity are associated, however confirming causals link to altered knee loading is challenging. This study leverages statistical shape models (SSM) to investigate the relationship between joint shape/alignment and knee loading during gait in knee OA(KOA) patients to understand their contribution to elevated medial knee loading in OA. Musculoskeletal (MSK) models were created for the mean as well as the first eightSSM principal modes of variation (-3,-2,-1, +1, +2, +3 standard deviations for each mode) and used as input to a MSK modeling framework. Using an identical KOA gait pattern (i.e., joint kinematics and ground reaction forces), we ran simulations for each MSK model and evaluated medial compartment loading magnitude and contact distribution at the instant of first and second peak of knee joint loading. An increase in external rotation, posterior tibia translation and a decrease in medial joint space and medial femoral condylar size predisposed the medial compartment knee joint to overloading during gait. This was coupled with an anterior and medial shift in contact location with increasing external rotated tibial position and increasing posterior tibial translation with respect to the femur. Next, results also highlighted a posterior shift of the medial compartment loading location with decreasing medial joint space. This study provides important population-based insights on how knee shape and alignment predispose individuals with KOA to elevated medial compartmental knee loading. This information can be crucial in assessing the risk for medial KOA development and progression.

Finding MeVO: Identifying Intracranial Medium-Vessel Occlusions at CT Angiography.

The development of methods to detect and treat intracranial large-vessel occlusions (LVOs) has revolutionized the management of acute ischemic stroke. CT angiography (CTA) of the head and neck is effective in depicting LVOs and widely used in the evaluation of patients who have had a stroke. Ongoing efforts are now focused on the potential to detect and treat intracranial medium-vessel occlusions (MeVOs), which by definition are smaller than LVOs and thus more difficult to detect with CTA. The authors review common and variant anatomies of medium-sized cerebral arteries and the appearance of a variety of MeVOs on CT angiograms. Possible pitfalls in MeVO detection include rare anatomic variants, calcified thrombi, and stump occlusions. Current recommendations for performing CTA and ancillary methods that might aid in MeVO detection are discussed. Understanding the relevant anatomy and the variety of appearances of MeVOs aids radiologists in identifying these occlusions, particularly in the setting of urgent stroke. ©RSNA, 2024 See the invited commentary by Ospel and Nguyen in this issue.

Imaging of the Inferior Mesenteric Vasculature.

The inferior mesenteric artery (IMA) and inferior mesenteric vein (IMV) supply and drain blood from the distal colon and rectum, respectively. Routinely imaged at cross-sectional imaging of the abdomen and pelvis, these vessels play a vital role in gastrointestinal tract health but may be neglected due to their diminutive caliber relative to other mesenteric vessels and potential lack of inclusion in routine search patterns. The authors describe and illustrate normal and abnormal appearances of the IMA and IMV and findings that are diagnostic of primary vascular abnormalities or can offer diagnostic clues. After the embryologic features, normal anatomy, and anatomic variants of the IMA and IMV are reviewed, various manifestations of IMA and IMV abnormalities, such as aneurysm and pseudoaneurysm, stenosis, occlusion, dissection, hemorrhage, arteriovenous malformations and fistulas, tumoral invasion, vasculitis, and perivascular lymphatic dilatation, are explored with use of case examples. The role of the IMA and IMV as collateral vasculature, including the clinical scenarios of superior mesenteric arterial occlusion, aortic endoleak, and portosystemic venous shunt, are discussed. Finally, diagnostic clues that the inferior mesenteric vessels and adjacent soft tissues can provide, including mesenteric venous gas, compression or displacement from bowel volvulus or internal hernias, lymphadenopathy, and venous flow artifacts, are highlighted. The authors provide a comprehensive reference for radiologists who evaluate the IMA and IMV on cross-sectional images and shine a spotlight on these neglected but important vessels. ©RSNA, 2024 Supplemental material is available for this article.

Basal Ganglia’s influence on awake testing in carotid endarterectomy

BackgroundWhite matter changes (WMC) have been associated with the underlying presence of chronic cerebral ischemia, such as in carotid stenosis and age-related white matter changes (ARWMC). A low attenuation on computed tomography (CT) characterizes these alterations. Patients undergoing carotid endarterectomy (CEA) with severe WMC may be at increased risk of intraoperative neurologic deficits (IND) during carotid clamping. This study aims to determine the potential role of ARWMC as a predictor of IND during CEA with regional anesthesia (RA). MethodsPatients undergoing CEA under RA at a tertiary referral center, who presented with IND during CEA were prospectively and consecutively recruited between January 2011 and December 2023. The control group comprised the immediately consecutive patient who underwent the same procedure without IND. From this sample, patients with preoperative CT were selected and compared based on ARWMC score (≤ 1 and 2). Differences in demographics and comorbidities were assessed between the groups. A multivariable logistic regression was performed. ResultsOne hundred and twenty-one patients were enrolled. Patients with IND had a significantly higher ARWMC score in basal ganglia (ARWMC-BG ≥ 2) and posterior circulation disease was more frequent (27.8 %). No significant differences were observed in anatomical variations of the circle of Willis.For patients with ARWMC-BG ≥ 2, a significant burden of other comorbidities was associated, such as chronic kidney disease, coronary disease, and atrial fibrillation. After multivariable logistic regression analysis, ARWMC-BG score ≥ 2 was an independent risk factor for IND (aOR 3.472). ConclusionAn ARWMC-BG score above 2 predicts positive intraoperative “awake tests” in CEA with RA, constituting a reliable tool to stratify patients according to their risk of adverse events. However, larger prospective cohorts are needed to validate these findings and offer a better selection and management of this subset of patients.

Asian Pacific Society of Cardiology Position Statement on the Use of Transcatheter Aortic Valve Implantation in the Management of Aortic Stenosis

Transcatheter aortic valve implantation (TAVI) has been established as an effective treatment modality in patients with severe aortic stenosis and the uptake of TAVI is rapidly growing in the Asia-Pacific region. However, there exists a heterogeneity in the management of aortic stenosis and the use of TAVI among countries in the region. Reasons for these differences include anatomical variations, disparity in healthcare resources and infrastructure and the lack of consensus on the optimal management of aortic stenosis in the Asia-Pacific region. Hence, an Asian Pacific Society of Cardiology (APSC) working group, including a multidisciplinary group of general and interventional cardiologists, cardiac surgeons and imaging specialists, developed a position statement on the recommendations for TAVI in the management of aortic stenosis. The APSC expert panel reviewed and appraised the available evidence using the Grading of Recommendations Assessment, Development, and Evaluation system. Recommendations were developed and put to an online vote. Consensus was reached when 80% of votes for a given recommendation were in support of ‘agree’ or ‘neutral.’ The resulting 28 statements provide guidance for clinical practitioners in the region on the use of TAVI in the treatment of patients with aortic stenosis.

Uncommon anatomical variation of the origin of the right upper pulmonary vein detected by 3D reconstruction prior to robotic segmentectomy

Uncommon anatomical variation of the origin of the right upper pulmonary vein detected by 3D reconstruction prior to robotic segmentectomy

Circle of Willis and Its Anatomical Relevance

The Circle of Willis is an arterial network located at the base of the brain, formed by the interconnection of the anterior, middle, and posterior cerebral arteries, along with the anterior and posterior communicating arteries. It connects the internal carotid arteries to the vertebral arteries, allowing the distribution of cerebral blood flow. Its significance lies in its ability to offer an alternative pathway in cases of arterial obstruction, helping to prevent cerebral ischemia. However, anatomical variations of this structure are common, and only 20% to 25% of the population has a "complete" or symmetrical configuration. Such variations can influence the risk of cerebrovascular diseases, such as stroke, as they may compromise the efficiency of the compensatory mechanism. These anatomical variations have a direct impact on the diagnosis and treatment of neurological conditions. The integrity of the Circle of Willis can influence the severity of symptoms in cases of ischemic strokes, as well as affect aneurysm formation and its clinical implications. Advances in imaging techniques, such as CT angiography and magnetic resonance imaging, have enabled more accurate diagnoses and the development of more effective treatments for conditions associated with the Circle of Willis, making its anatomical understanding essential for the prevention and management of cerebrovascular diseases.

Nonsurgical endodontic treatment of Type II dens invaginatus by removal of the internal structure of the tooth : a case report

Dens invaginatus is a developmental anomaly that occurs when the enamel organ is invaginated into the dental papilla before the process of calcification during tooth development. Dens invaginatus exhibits various anatomical variations, and these structural changes can complicate treatment. For effective management of dens invaginatus, it is crucial to accurately understand the internal structure of the tooth and to establish an appropriate treatment plan. Cone-beam computed tomography (CBCT) has proven to be a valuable tool for three-dimensional reconstruction of the tooth. This case report presents a maxillary lateral incisor with pulpal necrosis and periapical periodontitis. The case involves dens invaginatus characterized by a separate tooth structure, diagnosed using CBCT, and a treatment plan was established accordingly. For treatment, a dental microscope was used to remove the internal structure of the tooth, followed by filling with mineral trioxide aggregate (MTA).

Dural Venous Sinus Variations Observed in Magnetic Resonance Venography at a Tertiary Care Hospital: An Observational Study

Introduction: The dural venous system, composed of various sinuses, plays a crucial role in draining deoxygenated blood from the central nervous system. Understanding its anatomical variations is essential to differentiate it from pathological conditions like cerebral venous sinus thrombosis. This study aims to evaluate the anatomical variations of the dural venous sinuses using Magnetic Resonance Venography.Methods: An observational, cross-section study was performed in the Department of Radiology from September 2023 to March 2024 after the approval by the Institutional Review Committee (Reference number: 149/080/081(6-11)E2). Magnetic Resonance Venography of 109 adult patients was performed using a 1.5 Tesla MRI scanner. Diameters of the superior sagittal sinus, straight sinus, and transverse sinuses were measured. Variations in transverse sinuses, straight sinus, and confluence were categorized and analyzed. Results: The study included 52 (47.70%) male and 57 (52.30%) female, with median age of 42 (IQR: 30.5 - 56) years. The superior sagittal sinus had the diameter of 6.4±1 mm. Symmetric transverse sinus variant seen was in 80 (73.39%) patients, and left transverse sinus hypoplasia was seen in 20 (18.35%) patients. Variations in the straight sinus and confluence were also documented with a true confluence (type III) was seen in 71 (65.10%) patients.Conclusions: Anatomical variations of the dural venous sinuses as observed in 1.5 Tesla MRI was quite common.

The Significance of Biliary Anatomical Variation as a Key Indicator in Laparoscopic Bile Duct Injuries

Introduction: The science of Gastrointestinal (GI) endoscopy is the science and art of millimeters that has marvelously evolved over the past 30 years. Cholecystectomy, most of which is done laparoscopically, is one of the most common procedures performed today (approximately 750,000 cases are performed annually in the USA) and is considered relatively safe. However, laparoscopic cholecystectomy is associated with bile duct injuries. Several studies examining bile duct injuries have found significant rates of complication (0.39%---1.5%, that comes roughly to over 3,000 patient per year). Therefore, bile duct injuries are commonly encountered, and a clear understanding of the extensive variation in biliary anatomy is imperative to appropriately and successfully manage this common clinical problem to ultimately provide the highest level of patient care.

An Unusual Case of Maxillary First Molar: A Case Report

The success of root canal therapy depends on cleaning of all the infected root canals and three- dimensional hermetic seal of the canals. For this, the knowledge of the root canal anatomy plays a vital role. However, the root canal anatomy is not always predictable. It is complex due to various anatomic variations and recognizing it and cleaning it thoroughly is a challenge to clinicians. This case report presents root canal treatment of unusual anatomy of maxillary first molar with six root canals, two mesio-buccal, two disto- buccal and two palatal canals.

Radiographic Variants Associated With Allergic Fungal Rhinosinusitis: Key Differences for Pre-Operative Planning.

Allergic fungal rhinosinusitis (AFRS) often results in expansion of disease beyond the paranasal sinuses, which may put important structures, such as the anterior ethmoid artery (AEA) or lateral lamella of the cribiform, at risk of injury during endoscopic sinus surgery (ESS). This study aims to compare the AEA to skull base (AEA-SB) length in patients with AFRS versus chronic rhinosinusitis with nasal polyps (CRSwNP), as well as additional anatomic variants. A single institutional retrospective chart review of patients undergoing ESS for AFRS and CRSwNP was performed. AEA-SB length were compared between the 2 groups. Other anatomic variants, including Keros measurement and presence of supraorbital ethmoid air cells (SOEC), concha bullosa (CB), sphenoethmoidal, and infraorbital ethmoid cells were measured and compared between the 2 groups. Twenty-one patients were included in each cohort. The AFRS group was younger in age (P = .015) and had a significantly longer AEA-SB length (P = .014) compared to the CRSwNP group. No significant differences were observed between the 2 groups regarding Keros measurement, presence of concha bullosa, infraorbital ethmoid, sphenoethmoidal, or SOEC. No association was seen between AEA-SB length and Keros class in either group. AFRS harbors anatomical differences when compared to CRSwNP, with the former associated with a longer AEA-SB length. This key difference should be considered in preoperative planning to prevent injury to the AEA in patients undergoing ESS for AFRS.

The natural history of cerebral infundibula: A retrospective cohort study.

Debate exists regarding the true pathogenicity of cerebral infundibula (CI). Pre-aneurysmal lesions and benign anatomical variants have both been proposed. In this study, we present the largest single cohort series on the natural history of CI. Retrospective review of prospective surveillance of 420 CI was undertaken in a single tertiary cerebrovascular centre. All CI diagnosed by a neuroradiologist, diagnosed on either a Magnetic resonance angiography (MRA), Computed tomography angiography (CTA) or Digital subtraction angiography (DSA) were eligible for inclusion. Imaging and demographic characteristics were recorded at baseline. CI growth and aneurysm transformation were the outcomes of interest. Groupwise comparison was conducted via Fischer exact testing. Kaplan Meir curves and Cox proportional hazard ratios were used to assess variables of interest with respect to time on surveillance. 402 patients with 420 CI were surveyed over 2418 infundibula-years. Eleven CI (2.62%) grew on surveillance, and three (0.7%) transformed into aneurysms. Median time to growth was 85 months (36-263) and median time to aneurysm transformation was 112 months (96-142). Of the CI that grew, male sex and CI >2 mm at diagnosis were significant predictors of growth (all p<0.05). Of the CI that grew in surveillance, 2/11 (18.2%) transformed into aneurysms (p=0.001). Aneurysm transformation occurred at a rate of 1.27 per 1000 infundibula years. CI growth on surveillance (p= 0.00016) and size at diagnosis (p=0.038) remained significant predictors of aneurysm transformation on Kaplan Meir curves. The transformation of a CI to an aneurysm occurs at a low rate. A history of growth on surveillance imaging represents significant risk for aneurysm transformation.