Sagittal Images Research Articles

Femoral head decentration on hip MRI: comparison between imaging planes, methods of contrast administration, and hip deformities

ObjectivesTo compare the prevalence of femoral head decentration (FHD) on different MR imaging planes in patients undergoing direct/indirect hip MR arthrography (MRA) with asymptomatic controls and to evaluate its association with osseous deformities.MethodsIRB-approved retrospective single-center study of symptomatic hips undergoing direct or indirect hip MRA at 3 T. Asymptomatic participants underwent non-contrast hip MRI at 3 T. FHD was defined as a continuous fluid layer between the acetabulum and femoral head and assessed on axial, sagittal and radial images. The association of intra-articular/intra-venous contrast agents and the prevalence of FHD was evaluated. The association of FHD with osseous deformities and joint damage was assessed using multiple logistic regression analysis.ResultsThree-hundred ninety-four patients (447 hips, mean age 31 ± 9 years, 247 females) were included and compared to 43 asymptomatic controls (43 hips, mean age 31 ± 6 years, 26 females). FHD was most prevalent on radial images and more frequent in symptomatic hips (30% versus 2%, p < 0.001). FHD prevalence was not associated with the presence/absence of intra-articular contrast agents (30% versus 22%, OR = 1.5 (95% CI 0.9–2.5), p = 0.125). FHD was associated with hip dysplasia (OR = 6.1 (3.3–11.1), p < 0.001), excessive femoral torsion (OR = 3.0 (1.3–6.8), p = 0.010), and severe cartilage damage (OR = 3.6 (2.0–6.7), p < 0.001).ConclusionWhile rare in asymptomatic patients, femoral head decentration in symptomatic patients is associated with osseous deformities predisposing to hip instability, as well as with extensive cartilage damage.Critical relevance statementDecentration of the femoral head on radial MRA may be interpreted as a sign of hip instability in symptomatic hips without extensive cartilage defects. Its presence could unmask hip instability and yield promise in surgical decision-making.Key PointsThe best method of identifying femoral head decentration is radial MRI.The presence/absence of intra-articular contrast is not associated with femoral head decentration.Femoral head decentration is associated with hip deformities predisposing to hip instability.Graphical

Challenges in endoscopic third ventriculostomy for patients with achondroplasia: a focus on third ventricle floor anatomy.

Hydrocephalus is one of the neurological risks occurring in patients with achondroplasia. Ventriculoperitoneal shunt (VPS) insertion is the most common treatment. However, reports of successful endoscopic third ventriculostomy (ETV) suggest that ETV may be a good alternative to VPS insertion in achondroplasia. However, it has been stated that ETV in achondroplasia patients is technically demanding to perform. The current study examined the anatomical variations of the third ventricle and the brainstem in achondroplasia patients and correlated the findings with the difficulty of performing ETV. A retrospective analysis of 51 patients with achondroplasia and 138 hydrocephalus patients without achondroplasia (48 patients had tumor-related hydrocephalus and 90 patients had hydrocephalus of nontumorous origin) who have visited the authors' institution since 2012 was performed. Preoperative T2-weighted sagittal MR images were used to measure α (steepness of the third ventricle floor), β (endoscopic angle of incidence), d1 (vertical distance between the dorsum sellae and basilar bifurcation), and d2 (horizontal distance between the dorsum sellae and basilar artery). Each value was compared using the Tukey multicomparison test. Achondroplasia patients showed significantly smaller α (p < 0.001) and β (p < 0.001) angles, while there were no significant differences between the control groups (p = 0.947 for α, p = 0.836 for β). The d1 value was significantly larger in achondroplasia patients (p < 0.001), and d2 was smaller (p < 0.001). The control groups showed similar d1 and d2 values (p = 0.415 for d1, p = 0.154 for d2). Smaller α and β values meant that in achondroplasia patients the third ventricle floor stood more vertically than in other patients with hydrocephalus, and the endoscopic contact angles were small, increasing the risk of ventriculostomy devices slipping down into the infundibular recess. Additionally, a large d1 meant that the basilar artery was shifted upward and a small d2 indicated that the basilar artery was located closer to the dorsum sellae, potentially increasing the risk of basilar artery damage. Achondroplasia patients' skull and brain anatomies were significantly different from those of other hydrocephalus patients, with steeper third ventricle floors and basilar arteries closer to the dorsum sellae. Because these anatomical differences lead to difficulties in performing ETVs in achondroplasia patients, such differences should be considered when ETV is planned for the patients.

Relationship between carotid web morphology on CT angiography and stroke: A pooled multicenter analysis.

The Carotid web (CaW) is a cause of stroke, particularly in younger individuals. However, the frequency and the radiological features of the web's morphology associated with stroke risk are uncertain. We determined the CaW radiological features on computed tomography (CT) angiography associated with ipsilateral stroke. Data from six studies of patients with acute ischemic stroke were pooled. Identification and measurement of CaWs were performed by experienced readers using baseline neck CT angiography. We assessed six 2D CaW radiological features on sagittal oblique images, namely, main axis length, thickness, height, base width, distance to wall, and angle between the web main axis and carotid wall, and CaW volume on 3D images. CaWs were divided into symptomatic if acute ischemic stroke was in the ipsilateral internal carotid artery territory and its etiology was undetermined and asymptomatic if one condition was unmet. Univariable and multivariable analyses were conducted to assess the association between each radiological CaW feature and symptomatic CaW. Of the 3442 patients in the pooled data with assessable CTAs, 60 (1.7%) had CaW. In patients with CaW, median age was 59 (interquartile range [IQR]: 50-68) years, 60% were women, and 3 patients had bilateral CaWs. There were 39 (62%) symptomatic and 24 (38%) asymptomatic CaWs. Patients with symptomatic CaW were younger (55 (IQR: 49-61) years versus 69 (IQR: 52-75) years), had lower rates of hypertension (9 (25.0%) versus 12 (57.1%)) and more intracranial large vessel occlusions compared to patients with asymptomatic CaWs. After adjusting for age, hypertension, and occlusion location, CaW length (adjusted odds ratio (aOR) 1.84 (95% confidence interval [CI]: 1.03-3.28)), thickness (aOR: 2.31 (95% CI 1.08-4.97)), volume (aOR: 1.07 per 1 mm3 increment (95% CI: 1.01-1.12)), and angle relative to the carotid wall (aOR: 0.95 (95% CI: 0.91-0.99)) were associated with symptomatic CaW. Radiological assessment of CaW morphology may determine its potential causal role in ischemic stroke etiology. Symptomatic CaWs tend to be longer, larger, and oriented at more acute angles relative to the carotid wall as compared to asymptomatic CaWs.

Association of temporomandibular joint space and condylar head position with different skeletal patterns among the Malaysian population

During growth and development of the head and neck, some degree of interaction and interdependence between skeletal pattern with temporomandibular joint (TMJ) space and condylar head position occurs. Results from previous studies are varied; some reporting significant difference of TMJ space or condylar head position among the skeletal patterns, whilst others have shown that no such association is present. Considering that previous studies have been conducted in populations outside of Malaysia and the importance of determining the correlation between skeletal and TMJ morphology, this retrospective study was done to evaluate the TMJ space and condylar head position in different skeletal patterns among the Malaysian population using computed tomography (CT) images. A total of 90 CT images of the head and neck were included. Skeletal pattern (class I, II, III) was determined from each CT image based on the ANB angles obtained from reconstruction of these images. The TMJ space measurement and condylar head position were determined from sagittal images based on established landmarks from the reconstructed CT images. Statistical analysis was used to compare the TMJ space and condylar head position across the three skeletal classes and assess its significance. The results of this study demonstrated that there was no significant association between TMJ space or condylar head position in the different skeletal patterns among the Malaysian population. It is recommended that a prospective study with large sample size and standardized measurement techniques be implemented in the future to determine the precise association between TMJ morphology and different skeletal patterns.

Lumbar intervertebral disc detection and classification with novel deep learning models

Low back pain (LBP) is a prevalent spinal issue, affecting eight out of ten individuals. Notably, lumbar intervertebral disc (IVD) abnormalities frequently contribute to LBP. To diagnose LBP, Magnetic Resonance Imaging (MRI) is crucial for obtaining detailed spinal images. This paper employs deep learning (DL) to detect and locate lumbar IVD in sagittal MR images. It further classifies lumbar IVDs as healthy or herniated, utilizing both novel convolutional neural network (CNN) and conventional CNN models. The dataset utilized comprises MR images from 32 patients, with 10 exhibiting healthy discs and the remaining 22 posing a mix of healthy and herniated discs, totaling 160 lumbar discs, incorporating 112 healthy and 48 herniated discs. In this study, ResNet-50 architecture in the Novel Lumbar IVD detection (NLID) model served as the feature extractor to segment the five lumbar IVDs from MR images. The features extracted from ResNet-50 were input into YOLOv2 for the identification of the region of interest (ROI). The findings indicate that optimal performance was achieved at the 22nd Rectified Linear Unit (ReLU) activation layer, boasting a remarkable 99.59% average precision, 97.22% F1-score, 94.59% precision, and a perfect 100% recall. This commendable performance consistently held above the 85% threshold until the 22nd ReLU activation layer. Regarding imbalanced dataset classification, AlexNet emerged as the frontrunner among other pre-trained networks, boasting the highest test accuracy of 90.63%, and an impressive F1 score of 88.77%. Meanwhile, the Novel Lumbar IVD Classification (NLIC) model achieved superior results with 93.75% test accuracy, and 92.27% F1-score. In the setting of the balanced dataset, NLIC achieved 96.88% test accuracy, and 96.46% F1-score with fewer epochs compared to AlexNet, affirming the robustness of the novel trained-from-scratch network. These findings distinctly underscore the effectiveness of CNNs in both medical image segmentation and classification.

Anterior interhemispheric vs. pterional approach in the microsurgical management of anterior communicating artery aneurysms: a comparative analysis employing a novel multidimensional matching-tool

The surgical management of anterior communicating artery aneurysms (AcomA) is challenging due to their deep midline position and proximity to complex skull base anatomy. This study compares the pterional craniotomy with the interhemispheric approach based on the specific aneurysm angulation. A total of 129 AcomA cases were analyzed, with 50 undergoing microsurgical clipping via either the pterional or interhemispheric approach. All selected cases had computed tomography-angiography with sagittal imaging slices and 2D-angiography. Using an interactive tool, 14 cases treated via the interhemispheric approach were matched with 14 cases approached pterionally based on clinical and morphological parameters, emphasizing intracranial aneurysm (IA) dome angulation relative to the frontal skull base. Outcomes included IA occlusion, temporary clipping incidence, intraoperative rupture, postoperative strokes, hemorrhages, hydrocephalus, vasospasm, and patient functionality. Matched cohorts had consistent demographics. Both approaches resulted in similar IA occlusion rates, but the interhemispheric approach led to improved clinical outcomes, measured by the modified Rankin Scale. It also had a lower incidence of hydrocephalus and reduced need for permanent ventriculoperitoneal shunt placement. Vasospasms and postoperative infarction rates were comparable between the groups. Our findings suggest potential advantages of the interhemispheric approach in managing AcomA, depending on aneurysm angulation. Despite a small sample size, the results highlight the importance of customized surgical decision-making based on the unique traits of each aneurysm and the surgeon's expertise.

Comparing the clinical features of lateral and medial approaches of costoclavicular technique versus traditional lateral sagittal technique as infraclavicular brachial plexus block methods: a randomized controlled trial

BackgroundIt is aimed to compare the block onset times and performance features of costoclavicular techniques (medial and lateral approach) versus lateral sagittal technique.MethodsPatients were randomized into three groups. For costoclavicular techniques, ultrasound probe was placed parallel to clavicle obtaining nerve cords, axillary artery and axillary vein visual from lateral-to-medial, respectively. The block needle was advanced from lateral (Group CLB) or medial (Group CMB) to perform costoclavicular block. For lateral sagittal technique (Group LSB), ultrasound probe was placed sagittal and perpendicular below the coracoid process to obtain sagittal artery image with the cords around. Total 20 ml of 0.5% bupivacaine and 10 ml of 2% lidocaine were deposited for all groups. Sensory and motor block onset times, block performance properties, complications, and patient/surgeon satisfactions were investigated.ResultsAmong 56 patients, the primary outcome, sensory block onset time was shorter in Group CLB than Group CMB and Group LSB (10 [5–15], 10 [10–20], and 15 [10–15] minutes, respectively, p < 0.05). Motor block onset was also fastest in Group CLB (15 [10–20] mins for CLB, 20 [15–20] mins for LSB, and 22.5 [15–25] mins for CMB, p = 0.004). Block performance properties did not differ between the groups. The only complication observed was vascular puncture with an incidence of 28% in Group CMB.ConclusionsLateral approach costoclavicular technique provides fastest block onset than the other techniques. Considering the success and safety profile, this technique stands as a good alternative in clinical practice.Trial registrationThis study is prospectively registered to clinicaltrials.gov on 20/02/2022 (NCT05260736).

The posterior condyle grows in the direction of the increasing posterior condylar offset and the inclination angle of the ACL changes accordingly.

The purpose of this study was to reveal the changes in the shape of the posterior femoral condyle and the morphology of the ACL, both before and after epiphyseal closure. The hypothesis of this study is that the morphological change of the posterior femoral condyle and that of the ACL may be correlated to some extent. Eighty-one patients who underwent surgery for the knee joint (meniscal repair, arthroscopic synovectomy, medial patellofemoral ligament reconstruction) between 2016 and 2021 were included in this study, 48 patients aged 13 years or under (before epiphysis closure; mean age: 10.9 (range: 7-13) and 33 patients aged over 18 years or over (after epiphysis closure; mean age: 21.7 (range: 18-30). The shape of the posterior femoral condyle was evaluated via lateral view radiographs, and the morphology of the ACL was measured via sagittal and coronal magnetic resonance imaging (MRI) images. The morphology of the posterior condyle in the lateral view radiograph in patients aged 13 and under was larger in the direction of the short axis of the femur compared with that in those aged 18 and over (p < 0.001). The mean value of the inclination angle of the anterior cruciate ligament (ACL) in the sagittal plane was significantly smaller in patients aged 13 and under (41.7° ± 3.7) than in those aged 18 and over (48.5° ± 4.2) (p < 0.001). The mean values of the inclination angle of the ACL in the coronal plane were significantly smaller in patients aged 13 and under (55.7° ± 6.4) than in those aged 18 and over (63.4° ± 4.4) (p < 0.001). This study evaluates and compares the shape of the posterior femoral condyle and the morphology of the ACL fiber before and after epiphyseal closure. The posterior femoral condyle grew posteriorly rather than longitudinally, and the inclination of the ACL fibers was thought to change accordingly. Level Ⅲ.

A novel adapted MRI-based scheme for Dejour classification of trochlear dysplasia.

To elaborate an optimized scheme for the Dejour classification of trochlear dysplasia based on axial and sagittal MR images and to evaluate its intra- and inter-reader reliability. Over a period of 20months patients with a knee MRI and the diagnosis of trochlear dysplasia were retrospectively included. Exclusion criteria were incomplete examination, qualitatively non-diagnostic examination, post trochlear surgery, missing informed consent for research purposes. Three independent evaluations were performed by two radiologists: first using an established description of the Dejour classification (types A-D) and then two evaluations using a new adapted scheme (types A-D). The adapted scheme includes a shallow trochlea, in type A no spur/no cliff, in type B with spur/no cliff, in type C no spur/with cliff, and in type D with spur/with cliff. One hundred seventy-one knee MRIs (female:65.5%; left side:52.6%) were included with a median age of 34.3years (range:11.3-79.2). Inter-reader reliability using the established description was fair for the four-type-classification (kappa(k) = 0.23; 95%CI:0.11-0.34), fair for differentiation low-grade versus high-grade dysplasia (k = 0.28;0.13-0.43), slight for differentiation spur versus no-spur types (k = 0.20;0.05-0.34). Inter-reader reliability using the adapted scheme was substantial (k = 0.79;0.75-0.83) for the four-type-classification, substantial for differentiation low-grade versus high-grade dysplasia (k = 0.80;0.75-0.85), substantial for differentiation spur versus no-spur presence (k = 0.76;0.71-0.81). Intra-reader reliability was almost perfect for the adapted scheme (k-values: 0.88-0.95; 95%CIs: 0.84-0.98). The novel adapted scheme for Dejour classification shows an almost perfect intra-reader reliability and a substantially higher inter-reader reliability. It may become a helpful tool in the daily diagnostic work of radiologists.

Development and first implementation of a novel multi-modality cardiac motion and dosimetry phantom for radiotherapy applications.

Cardiac applications in radiation therapy are rapidly expanding including magnetic resonance guided radiation therapy (MRgRT) for real-time gating for targeting and avoidance near the heart or treating ventricular tachycardia (VT). This work describes the development and implementation of a novel multi-modality and magnetic resonance (MR)-compatible cardiac phantom. The patient-informed 3D model was derived from manual contouring of a contrast-enhanced Coronary Computed Tomography Angiography scan, exported as a Stereolithography model, then post-processed to simulate female heart with an average volume. The model was 3D-printed using Elastic50A to provide MR contrast to water background. Two rigid acrylic modules containing cardiac structures were designed and assembled, retrofitting to an MR-safe programmable motor to supply cardiac and respiratory motion in superior-inferior directions. One module contained a cavity for an ion chamber (IC), and the other was equipped with multiple interchangeable cavities for plastic scintillation detectors (PSDs). Images were acquired on a 0.35 T MR-linac for validation of phantom geometry, motion, and simulated online treatment planning and delivery. Three motion profiles were prescribed: patient-derived cardiac (sine waveform, 4.3mm peak-to-peak, 60 beats/min), respiratory (cos4 waveform, 30mm peak-to-peak, 12 breaths/min), and a superposition of cardiac (sine waveform, 4mm peak-to-peak, 70 beats/min) and respiratory (cos4 waveform, 24mm peak-to-peak, 12 breaths/min). The amplitude of the motion profiles was evaluated from sagittal cine images at eight frames/s with a resolution of 2.4mm × 2.4mm. Gated dosimetry experiments were performed using the two module configurations for calculating dose relative to stationary. A CT-based VT treatment plan was delivered twice under cone-beam CT guidance and cumulative stationary doses to multi-point PSDs were evaluated. No artifacts were observed on any images acquired during phantom operation. Phantom excursions measured 49.3±25.8%/66.9±14.0%, 97.0±2.2%/96.4±1.7%, and 90.4±4.8%/89.3±3.5% of prescription for cardiac, respiratory, and cardio-respiratory motion profiles for the 2-chamber (PSD) and 12-substructure (IC) phantom modules respectively. In the gated experiments, the cumulative dose was<2% from expected using the IC module. Real-time dose measured for the PSDs at 10Hz acquisition rate demonstrated the ability to detect the dosimetric consequences of cardiac, respiratory, and cardio-respiratory motion when sampling of different locations during a single delivery, and the stability of our phantom dosimetric results over repeated cycles for the high dose and high gradient regions. For the VT delivery, high dose PSD was<1% from expected (5-6 cGy deviation of 5.9Gy/fraction) and high gradient/low dose regions had deviations<3.6% (6.3 cGy less than expected 1.73Gy/fraction). A novel multi-modality modular heart phantom was designed, constructed, and used for gated radiotherapy experiments on a 0.35 T MR-linac. Our phantom was capable of mimicking cardiac, cardio-respiratory, and respiratory motion while performing dosimetric evaluations of gated procedures using IC and PSD configurations. Time-resolved PSDs with small sensitive volumes appear promising for low-amplitude/high-frequency motion and multi-point data acquisition for advanced dosimetric capabilities. Illustrating VT planning and delivery further expands our phantom to address the unmet needs of cardiac applications in radiotherapy.

The predominant insertion of the ischiofemoral ligament is a merging to the iliofemoral ligament as demonstrated on magnetic resonance arthrogram studies.

The capsular ligaments at the hip joint work in synchrony with the acetabulum and femoral head for articular stability. There is a lack of understanding about ischiofemoral ligament (ISFL) anatomy and function. To assess the insertion of the ISFL in non-arthritic adult hips. A retrospective analysis was performed in 72 patients who underwent magnetic resonance arthrogram (MRA) for the assessment of hip pain. The distribution of the ISFL components, the thickness, and the insertion site were assessed by concomitantly using the axial oblique, coronal, and sagittal MRA images. Two insertions of the ISFL anterior to the center of the femoral head were identified in 71 (99%) hips: (i) predominant anterior merging with the iliofemoral ligament as continuation of zona orbicularis, observed in all hips; and (ii) anterolateral junction of femoral neck and greater trochanter. Two ISFL parts (proximal and distal) were identified in 70 (97%) of the 72 studied hips. The proximal part was always thinner (mean 2.6 ± 0.7 mm) and originated from the ischium at the acetabular rim. The distal part was a continuation of the zona orbicularis, and the mean thickness was 6.7 ± 1.6 mm. Both parts merged as they coursed over the superior portion of the femoral head. The predominant insertion of the ischiofemoral ligament is a merging to the iliofemoral ligament anteriorly. Surgical procedures such as hip arthroscopy involving the ISFL will affect the function of the iliofemoral ligament, and vice versa.

Anatomical Variations of the Canalis Sinuosus: A CBCT Study

Objective: Canalis sinuosus (CS) is a bony canal separated from the infraorbital nerve containing the anterior superior alveolar vessel-nerve bundle. This study aimed to assess the anatomical variations of the canalis sinuosus from cone-beam computed tomography (CBCT) images. Methods: CBCT images of 568 patients (328 females and 240 males; aged between 18 and 81 years old) were evaluated retrospectively. Axial, sagittal, coronal, and cross-sectional images with 0.5 mm slice thicknesses were used to evaluate the presence of CS and associated accessory canal (AC). Results: Bilateral CS was detected in the entire sample (n=568, 100%). A total of 340 ACs were detected, including at least one AC in 41.9% of the patients. The median value of AC diameter was calculated as 0.89 mm both for females and males. ACs were found in 135 females and in 103 males. One up to five ACs were found per patient. However, the majority of the patients had one AC. ACs were mostly located at tooth region 11 (17.9%) and tooth region 12 (16.4%). Only 59.71% of ACs had a radiographically observed foramen. Conclusion: In conclusion, all patients had CS and ACs were in nearly half of the patients. Knowledge about these structures aid to correct radiographic diagnosis of these canals and minimize the risk of complications during surgical procedures.

Cervical spinal cord morphometrics in degenerative cervical myelopathy: quantification using semi-automated normalized technique and correlation with neurological dysfunctions

Degenerative cervical myelopathy (DCM) is characterized by spinal cord atrophy. Accurate estimation of spinal cord atrophy is key to the understanding of neurological diseases, including DCM. However, its clinical application is hampered by difficulties in its precise and consistent estimation due to significant variability in spinal cord morphometry along the cervical spine, both within and between individuals. To characterize morphometrics of the compressed spinal cord in DCM patients. We employed our semiautomated analysis framework that incorporates the Spinal Cord Toolbox (SCT) and a normalization approach to effectively address the challenges posed by cord compression in these patients. Additionally, we examined the clinical relevance of these morphometric measures to enhance our understanding of DCM pathophysiology. Prospective study. This study investigated 36 DCM patients and 31 healthy controls (HCs). Clinical scores including 9-hole peg test for hand dexterity, hand grip strength, balance, gait speed, modified Japanese Orthopaedic Association (mJOA) score, and imaging-based spinal cord morphometrics. Using the generic spine acquisition protocol and our semiautomated analysis pipeline, spinal cord morphometrics, including cross-sectional area (CSA), anterior-posterior (AP) and transverse (RL) diameters, eccentricity, and solidity, were estimated from sagittal T2w magnetic resonance imaging (MRI) images using the Spinal Cord Toolbox (SCT). Normalized metrics were extracted from the C1 to C7 vertebral levels and compared between DCM patients and HC. Morphometric data at regions of maximum spinal cord compression (MSCC) were correlated with the clinical scores. A subset of participants underwent follow-up scans at 6 months to monitor longitudinal changes in spinal cord atrophy. Spinal cord morphometric data were normalized against the healthy population morphometry (PAM50 database) and extracted for all participants. DCM patients showed a notable reduction in CSA, AP, and RL diameter across all vertebral levels compared to HC. MSCC metrics correlated significantly with clinical scores like dexterity, grip strength, and mJOA scores. Longitudinal analysis indicated a decrease in CSA and worsening clinical scores in DCM patients. Our processing pipeline offers a reliable method for assessing spinal cord compression in DCM patients. Normalized spinal cord morphometrics, particularly the CSA could have potential for monitoring DCM disease severity and progression, guiding treatment decisions. Furthermore, to our knowledge our study is the first to apply the generic spinal cord acquisition protocol, ensuring consistent imaging across different MRI scanners and settings. Coupled with our semiautomated analysis pipeline, this protocol is key for the detailed morphometric characterization of compressed spinal cords in patients with DCM, a disease that is both complex and heterogenous. This study was funded by the National Institute of Neurological Disorders and Stroke (NINDS) (K23:NS091430) and (R01: NS129852-01A1).

Multi-planar dual adversarial network based on dynamic 3D features for MRI-CT head and neck image synthesis

Objective. Head and neck radiotherapy planning requires electron densities from different tissues for dose calculation. Dose calculation from imaging modalities such as MRI remains an unsolved problem since this imaging modality does not provide information about the density of electrons. Approach. We propose a generative adversarial network (GAN) approach that synthesizes CT (sCT) images from T1-weighted MRI acquisitions in head and neck cancer patients. Our contribution is to exploit new features that are relevant for improving multimodal image synthesis, and thus improving the quality of the generated CT images. More precisely, we propose a Dual branch generator based on the U-Net architecture and on an augmented multi-planar branch. The augmented branch learns specific 3D dynamic features, which describe the dynamic image shape variations and are extracted from different view-points of the volumetric input MRI. The architecture of the proposed model relies on an end-to-end convolutional U-Net embedding network. Results. The proposed model achieves a mean absolute error (MAE) of 18.76±5.167 in the target Hounsfield unit (HU) space on sagittal head and neck patients, with a mean structural similarity (MSSIM) of 0.95±0.09 and a Frechet inception distance (FID) of 145.60±8.38 . The model yields a MAE of 26.83±8.27 to generate specific primary tumor regions on axial patient acquisitions, with a Dice score of 0.73±0.06 and a FID distance equal to 122.58±7.55 . The improvement of our model over other state-of-the-art GAN approaches is of 3.8%, on a tumor test set. On both sagittal and axial acquisitions, the model yields the best peak signal-to-noise ratio of 27.89±2.22 and 26.08±2.95 to synthesize MRI from CT input. Significance. The proposed model synthesizes both sagittal and axial CT tumor images, used for radiotherapy treatment planning in head and neck cancer cases. The performance analysis across different imaging metrics and under different evaluation strategies demonstrates the effectiveness of our dual CT synthesis model to produce high quality sCT images compared to other state-of-the-art approaches. Our model could improve clinical tumor analysis, in which a further clinical validation remains to be explored.

Exploring deep learning strategies for intervertebral disc herniation detection on veterinary MRI

Intervertebral Disc Herniation (IVDH) is a common spinal disease in dogs, significantly impacting their health, mobility, and overall well-being. This study initiates an effort to automate the detection and localization of IVDH lesions in veterinary MRI scans, utilizing advanced artificial intelligence (AI) methods. A comprehensive canine IVDH dataset, comprising T2-weighted sagittal MRI images from 213 pet dogs of various breeds, ages, and sizes, was compiled and utilized to train and test the IVDH detection models. The experimental results showed that traditional two-stage detection models reliably outperformed one-stage models, including the recent You Only Look Once X (YOLOX) detector. In terms of methodology, this study introduced a novel spinal localization module, successfully integrated into different object detection models to enhance IVDH detection, achieving an average precision (AP) of up to 75.32%. Additionally, transfer learning was explored to adapt the IVDH detection model for a smaller feline dataset. Overall, this study provides insights into advancing AI for veterinary care, identifying challenges and exploring potential strategies for future development in veterinary radiology.

Patellar articular overlap is better associated with patellar alignment during weight-bearing than traditional measures of patellar height

BackgroundA consequence of a high riding patella is reduced osseous stability and malalignment of the patella (i.e., lateral patellar tilt and displacement). Although quantification of patellar height is a routine part of the radiographic examination of the patellofemoral joint, it is not clear which measure of patellar height is best associated with patella alignment. Hypothesis/PurposeTo determine if patellar articular overlap (PAO) is better associated with lateral patellar tilt and lateral patellar displacement compared to traditional measures of patellar height. Study Design: Cross-sectional. MethodsMagnetic resonance images were obtained from 50 female participants (21 with patellofemoral pain and 29 healthy controls) under loaded conditions (25–35% bodyweight) at 15–20 degrees of knee flexion. Measurements of lateral patellar tilt and displacement as well as the PAO, Insall-Salvati ratio (ISV), Caton Deschamps-index (CD-index), or the Blacburn Peel-index (BP-index) were obtained from sagittal and axial plane images. ResultsThe PAO was found to significantly correlated with lateral patellar tilt (r = −0.77, p < 0.001). In contrast, the ISV, CD-index, or the BP-index were not found to be associated with lateral patellar tilt (r = 0.13, p = 0.34; r = −0.14, p = 0.33; r = −0.08, p = 0.56, respectively). Both the PAO and ISV were found to be significantly correlated with lateral patellar displacement (r = −0.52, p < 0.001; r = 0.43, p = 0.002, respectively). Conversely, the CD-index and BP-index were not found to be associated with lateral patellar displacement (r = 0.03 p = 0.83; r = 0.05 p = 0.74, respectively). ConclusionOf the measures of patellar height evaluated, the PAO was found to provide the greatest association with lateral patellar tilt and displacement.

Assessment of variations in the nasopalatine canal on CBCT: considerations from an anatomical point of view.

The nasopalatine canal (NPC) is one of the most significant anatomical markers in the anterior maxillary region. Its location is quite important, especially for implant placement. Therefore, the purpose of this study was to use cone-beam computed tomography (CBCT) to evaluate the morphology, size, and anatomic variations of the NPC. A total of 150 individual CBCT images were assessed in various sections to evaluate the dimensions, morphology, and extent of the NPC. Reformatted sagittal images were chosen to classify the shape and course of the canal. The Student's t-test, the χ² test, and Pearson correlation coefficients were used. The NPC was longer in males than in females, and the mediolateral diameter of the canal was greater in older adults. In sagittal sections, the canal predominantly exhibits a cylindrical shape, while a spindle shape is the least common. In coronal sections, a single shape is most frequently observed, with a Y-shape being the least common. Regarding the orientation of the canal, slanted canals are more prevalent, whereas vertically curved canals are rare. Typically, 2 canal openings are observed, with 4 openings being the least common. The current study highlights the challenges associated with identifying the anatomical appearance and variations of the NPC. Consequently, possessing a thorough understanding of this anatomy is essential before undertaking any surgical procedures, such as implant placement. This knowledge helps prevent complications such as nerve injury-related loss of sensation, bleeding due to blood vessel injury, and the development of a nasopalatine duct cyst following trauma to the canal during surgery.

A visual marker for early atrophy of the supraspinatus muscle on conventional MRI: introduction of the blackbird sign.

The aim of this study was to introduce the blackbird sign as a fast, qualitative measure of early supraspinatus (SSP) muscle atrophy and to correlate the sign with quantitatively assessed muscle volume and intramuscular fat fraction (FF) in patients with full-thickness SSP tears. The blackbird sign describes the asymmetric pattern of early SSP atrophy: on sagittal MR images, the supero-posterior contour of the muscle becomes concave, resembling the shape of a blackbird. MRIs of patients with full-thickness SSP tears were retrospectively reviewed for the presence of the blackbird and tangent signs. Patients were then divided into group 1: negative tangent sign and negative blackbird sign (n = 67), group 2: negative tangent sign and positive blackbird sign (n = 31), and group 3: positive tangent sign (n = 32). A 2-point Dixon sequence was acquired in all patients from which quantitative FF and muscle volumes were calculated. In total 130 patients (mean age 67 ± 11 years) were included. Mean SSP volume was significantly smaller in group 3 (15.8 ± 8.1 cm3) compared to group 2 (23.9 ± 7.0 cm3, p = 0.01) and group 1 (29.7 ± 9.1 cm3, p < 0.01). Significantly lower muscle volumes were also found in group 2 compared to group 1 (p = 0.02), confirming that the blackbird sign is able to identify early SSP atrophy. Mean FF in the SSP was significantly higher in group 3 (18.5 ± 4.4%) compared to group 2 (10.9 ± 4.7%, p < 0.01) and group 1 (6.1 ± 2.6%, p < 0.01). Visual assessment of early muscle atrophy of the SSP is feasible and reproducible using the blackbird sign, allowing the diagnosis of early SSP atrophy. In routine clinical practice, the blackbird sign may be a useful tool for assessing early muscle degeneration before the risk of postoperative rotator cuff re-tears increases with progressive muscle atrophy and fatty infiltration. Quantitative measurements of rotator cuff injuries require time, limiting clinical practicality. The proposed blackbird sign is able to identify early SSP atrophy. Reader agreement for the blackbird sign was substantial, demonstrating reproducibility and ease of implementation in the clinical routine.

Multi-Quantifying Maxillofacial Traits via a Demographic Parity-Based AI Model.

Objective and Impact Statement: The multi-quantification of the distinct individualized maxillofacial traits, that is, quantifying multiple indices, is vital for diagnosis, decision-making, and prognosis of the maxillofacial surgery. Introduction: While the discrete and demographically disproportionate distributions of the multiple indices restrict the generalization ability of artificial intelligence (AI)-based automatic analysis, this study presents a demographic-parity strategy for AI-based multi-quantification. Methods: In the aesthetic-concerning maxillary alveolar basal bone, which requires quantifying a total of 9 indices from length and width dimensional, this study collected a total of 4,000 cone-beam computed tomography (CBCT) sagittal images, and developed a deep learning model composed of a backbone and multiple regression heads with fully shared parameters to intelligently predict these quantitative metrics. Through auditing of the primary generalization result, the sensitive attribute was identified and the dataset was subdivided to train new submodels. Then, submodels trained from respective subsets were ensembled for final generalization. Results: The primary generalization result showed that the AI model underperformed in quantifying major basal bone indices. The sex factor was proved to be the sensitive attribute. The final model was ensembled by the male and female submodels, which yielded equal performance between genders, low error, high consistency, satisfying correlation coefficient, and highly focused attention. The ensemble model exhibited high similarity to clinicians with minor processing time. Conclusion: This work validates that the demographic parity strategy enables the AI algorithm with greater model generalization ability, even for the highly variable traits, which benefits for the appearance-concerning maxillofacial surgery.

Impact of Preoperative Intervertebral Disc Degeneration on Patient-Reported Outcome Measures After Lumbar Fusion

The Pfirrmann scoring system classifies lumbosacral disc degeneration based on MRI signal intensity. The relationship between pre-existing disc degeneration and PROMs after one-level lumbar fusion is not well documented. The purpose of this study was to investigate the relationship between the severity of preoperative intervertebral disc degeneration and pre- and postoperative patient-reported outcome measures (PROMs) in patients undergoing one-level lumbar fusion. All adult patients underwent posterior lumbar decompression and fusion (PLDF) or transforaminal lumbar interbody fusion (TLIF) between 2014-2022 were included. Patient demographics, and comorbidities were extracted from medical records. Lumbar intervertebral discs on sagittal MRI T2-weighted images were assessed by two independent graders utilizing Pfirrmann criteria. Grades I-III were categorized as low-grade disc degeneration, while IV-V were considered high-grade. Multivariable linear regression assessed the impact of disc degeneration on PROMS. A total of 150 patients were included, of which, 69 (46%) had low grade disc degeneration, while 81 (54%) had high grade degeneration. Patients with high-grade degeneration had increased preoperative VAS-Leg scores (6.10 vs. 4.54, p=0.005) and displayed greater one-year postoperative improvements in VAS-Back scores (-2.11 vs -0.66, p=0.002). Multivariable regression demonstrated Pfirrmann scores as independent predictors for both preoperative VAS-Leg scores (p=0.004) and postoperative VAS-Back improvement (p=0.005). In patients undergoing one-level lumbar fusion, higher Pfirmann scores were associated with increased preoperative leg pain and greater one-year postoperative improvement in back pain. Further studies into the relationship of pre-operative disc degeneration and their impact on postoperative outcomes may help guide clinical decision making and patient expectations.