T2-weighted Magnetic Resonance Imaging Sequences Research Articles

Utility of T2-weighted MRI and contrast-enhanced MRA in locating the fistula level of spinal arteriovenous fistula.

To investigate the value of routine T2-weighted magnetic resonance imaging (MRI) and contrast-enhanced magnetic resonance angiography (CE-MRA) sequences in locating the fistula level of spinal arteriovenous fistula (SAVF). Retrospectively analyzed the radiological findings of patients with SAVF diagnosed by surgery from May 2018 to September 2024. All patients completed spinal CE-MRA and routine T2-weighted MRI. The imaging manifestations of SAVF lesions on CE-MRA and MRI were summarized and analyzed. We enrolled 40 cases with SAVF (average age 58.1 years old, 85.0% male). The majority of fistulas were located in the thoracic (60.0%), followed by the lumbar (27.5%), and cervical (12.5%). Based on CE-MRA images, the fistula of 33 cases (82.5%) with SAVF can be accurately located, the perimedullary varicose vessels of 34 cases (89.47%) can be shown, and the feeding arteries of 27 cases (71.05%) can be identified. Based on T2-weighted MRI, the perimedullary flow voids and T2 hyperintensity were seen in 36 (90.0%) of SAVF cases, the fistula level in 88.9% (32/36) of cases was located at one end of the flow voids within 1 vertebral level, and the flow voids of 72.2% (26/36) cases near the fistula to be more tension. There is no significant difference in the accuracy of routine T2-weighted MRI in locating the fistula level compared to CE-MRA and digital subtraction angiography (DSA). Both routine T2-weighted MRI and CE-MRA sequences are valuable in the detection of SAVF fistula, we can locate the fistula level by the clues of the perimedullary varicose vessels.

Associations between structural brain changes and blood neurofilament light chain protein in treatment-resistant schizophrenia

Objective: Around 30% of people with schizophrenia are refractory to antipsychotic treatment (treatment-resistant schizophrenia). Abnormal structural neuroimaging findings, in particular volume and thickness reductions, are often described in schizophrenia. Novel biomarkers of active brain pathology such as neurofilament light chain protein are now expected to improve current understanding of psychiatric disorders, including schizophrenia. This study explored whether treatment-resistant schizophrenia individuals exhibit different associations between plasma neurofilament light chain protein levels and regional cortical thickness reductions compared with controls. Methods: Plasma neurofilament light chain protein levels were measured, and T1-weighted magnetic resonance imaging sequences were obtained and processed via FreeSurfer for each participant. General linear models adjusting for age and body mass index were estimated to determine whether the interaction between diagnostic group and plasma neurofilament light chain protein level predicted lower cortical thickness across frontotemporal structures and the insula. Results: A total of 79 participants were included: 37 treatment-resistant schizophrenia and 42 healthy controls. Significant (false discovery rate-corrected) cortical thinning of the left ( p = 0.005, η2 p = 0.100) and right ( p = 0.002, η2 p = 0.149) insula, and left inferior temporal gyrus ( p < 0.001, η2 p = 0.143) was associated with higher levels of plasma neurofilament light chain protein in treatment-resistant schizophrenia, but not in healthy controls. Conclusions: The association between regional thickness reduction of the bilateral insula and left inferior temporal gyrus with plasma neurofilament light chain protein may reflect a neuroprogressive component to schizophrenia, which is not observed in the normal population.

MRI in the evaluation of plantar plate disease: diagnostic value of the “stress test”

Abstract Introduction The plantar plate, also called the plantar ligament, is a fibrocartilaginous structure found in the metatarsophalangeal (MTP) and interphalangeal (IP) joints. Our study aimed to evaluate the role of magnetic resonance imaging (MRI) performed with the patient in the standard position or with joint hyperextension (the “stress test”, ST) in the study of plantar plate (PP) disease that involves metatarsophalangeal joints. Materials and methods All patients underwent forefoot MRI (Atroscan C, Esaote, Genoa, Italy), operating at 0.2 T. All patients first underwent a standard MRI examination (coronal T1 and T2 weighted image (WI) with fat suppression and axial and sagittal T2 WI); the examination was completed by performing a stress test (hyperextension of toes). The ST is an easy task to perform and is not time-consuming (requiring only one additional sagittal fast spin echo (FSE) T2-weighted MRI sequence; repetition time/ echo time (TR/TE): 3200/90 ms) for patients and operators. A 45°-dorsiflexion ST was performed for approximately 2.30 min, the time required to complete the sequence. No further diagnostic investigations were necessary; no patients underwent arthrography or arthro-MRI. The examinations were performed in a double-blind mode by two operators with proven experience in musculoskeletal radiology; no cases of intra-operator discordance were found. Results Twenty-five patients were recruited into our study over a 2-year period; 15 were positive for metatarsal pain and 10 were controls. Before treatment (surgery), all patients displaying symptoms underwent evaluation. As a result, the imaging features accurately represented the natural and actual conditions of the lesions. Among the symptomatic patients, 11 out of the 15 exhibited a PP tear or dysfunction in both the standard position and the ST. Additionally, two out of the 15 individuals displayed a tear in the ST alone, with no indication of it in the standard position. In contrast, two out of 15 patients showed no evidence of a PP tear in either the standard position or the ST. However, these two patients demonstrated dorsal subluxation during the ST, likely due to micro-instability resulting from PP failure. In the asymptomatic patients, nine out of the 10 individuals were found to be negative for PP dysfunction. Only one out of the 10 patients exhibited dorsal subluxation solely in the ST, indicative of plantar plate dysfunction, but no evidence of a tear in the PP. In the asymptomatic patients, standard MRI provided a specificity of 100% and a high negative predictive value (NPV) (90%), while the latter increased with the ST (specificity and NPV equal to 100%). In symptomatic patients, standard MRI gave a sensitivity of 75% when assessing a PP tear, which increased to 100% with the ST; the sensitivity of standard MRI the evaluation of MF subluxation was 60%, but it reached 100% with the ST. Conclusions In our study, by introducing the ST, the sensitivity in both the diagnosis of a PP tear and the evaluation of MTP subluxation reached 100% (a surgical assessment was performed on all positive patients for confirmation). Ultrasound has the advantage of being a non-invasive method. However, comparing the results of our study with the data available in the literature, ultrasound has a lower sensitivity and a negative predictive value. Also, ultrasound does not allow for the assessment of possible bone marrow oedema or the degree of concomitant arthritis. If other studies in the literature confirm these results, it will be possible to consider incorporating the ST into diagnostic practice in the future.

Functional localization of the human auditory and visual thalamus using a thalamic localizer functional magnetic resonance imaging task

Abstract Functional magnetic resonance imaging (fMRI) of the auditory and visual sensory systems of the human brain is an active area of investigation in the study of human health and disease. The medial geniculate nucleus (MGN) and lateral geniculate nucleus (LGN) are key thalamic nuclei involved in the processing and relay of auditory and visual information, respectively, and are the subject of blood-oxygen-level-dependent (BOLD) fMRI studies of neural activation and functional connectivity in human participants. However, localization of BOLD fMRI signal originating from neural activity in MGN and LGN remains a technical challenge, due, in part, to the poor definition of boundaries of these thalamic nuclei in standard T1-weighted and T2-weighted magnetic resonance imaging sequences. Here, we report the development and evaluation of an auditory and visual sensory thalamic localizer (TL) fMRI task that produces participant-specific functionally-defined regions of interest (fROIs) of both MGN and LGN, using 3 Tesla multiband fMRI and a clustered-sparse temporal acquisition sequence, in less than 16 minutes of scan time. We demonstrate the use of MGN and LGN fROIs obtained from the TL fMRI task in standard resting-state functional connectivity (RSFC) fMRI analyses in the same participants. In RSFC analyses, we validated the specificity of MGN and LGN fROIs for signals obtained from primary auditory and visual cortex, respectively, and benchmarked their performance against alternative atlas- and segmentation-based localization methods. The TL fMRI task and analysis code (written in Presentation and MATLAB, respectively) have been made freely available to the wider research community.

Functional Localization of the Human Auditory and Visual Thalamus Using a Thalamic Localizer Functional Magnetic Resonance Imaging Task.

Functional magnetic resonance imaging (fMRI) of the auditory and visual sensory systems of the human brain is an active area of investigation in the study of human health and disease. The medial geniculate nucleus (MGN) and lateral geniculate nucleus (LGN) are key thalamic nuclei involved in the processing and relay of auditory and visual information, respectively, and are the subject of blood-oxygen-level-dependent (BOLD) fMRI studies of neural activation and functional connectivity in human participants. However, localization of BOLD fMRI signal originating from neural activity in MGN and LGN remains a technical challenge, due in part to the poor definition of boundaries of these thalamic nuclei in standard T1-weighted and T2-weighted magnetic resonance imaging sequences. Here, we report the development and evaluation of an auditory and visual sensory thalamic localizer (TL) fMRI task that produces participant-specific functionally-defined regions of interest (fROIs) of both MGN and LGN, using 3 Tesla multiband fMRI and a clustered-sparse temporal acquisition sequence, in less than 16 minutes of scan time. We demonstrate the use of MGN and LGN fROIs obtained from the TL fMRI task in standard resting-state functional connectivity (RSFC) fMRI analyses in the same participants. In RSFC analyses, we validated the specificity of MGN and LGN fROIs for signals obtained from primary auditory and visual cortex, respectively, and benchmark their performance against alternative atlas- and segmentation-based localization methods. The TL fMRI task and analysis code (written in Presentation and MATLAB, respectively) have been made freely available to the wider research community.

More negative sagittal tibial tuberosity-trochlear groove distances are correlated with larger patellofemoral chondral lesion size.

The purpose of this study is to assess the association between sagittal tibial tuberosity-trochlear groove (sTT-TG) distance and patellofemoral chondral lesion size in patients undergoing cartilage restoration procedures. A retrospective cohort analysis of patients who underwent an osteochondral allograft transplantation or matrix-induced autologous chondrocyte implantation in the patellofemoral compartment, from 2010 to 2020, were included if they had patellofemoral high-grade lesions, magnetic resonance imaging (MRI) and minimum 2-year follow-up. The preoperative sTT-TG distance was measured independently on axial T2-weighted MRI sequences by two authors, each at least two weeks apart. Intraoperative lesion size was reported according to operative report measurements by the attending surgeon. An interclass correlation coefficient (ICC) was calculated to assess intra- and inter-rater reliability, and categorical data analysis and linear regression models were used to assess the relationship between sTT-TG and lesion size. A total of 80 patients (50 females) with a mean age of 31.5 ± 10.4 years, body mass index of 27.0 ± 5.9 kg/m2 and follow-up of 61.5 ± 21.4 months were included. A total of 107 lesions were present: 63 patients with unipolar (patella = 41, trochlea = 22) and 22 with bipolar lesions. The mean MRI defect size was 1.6 ± 1.0 cm2 and the mean intraoperative defect size was 3.8 ± 2.4cm2. Intra- (ICC: 0.99,0.98) and inter-rater reliability (ICC: 0.96) were excellent for both MRI defect size and sTT-TG measurements. The mean sTT-TG was -4.8 ± 4.9 mm and was significantly inversely related to MRI defect size (-0.45, p < 0.01), intraoperative patellar lesion size (-0.32, p = 0.01), total lesion area (-0.22, p = 0.04), but not trochlear lesion size (-0.09, p = 0.56). Multivariable regression demonstrated a more negative sTT-TG remained an independent variable correlated with larger MRI-measured patellofemoral defect sizes and intraoperative patellar lesions. A more negative sTT-TG was an independent variable correlated with larger patellofemoral lesions in patients undergoing patellofemoral cartilage restoration. Level III, Diagnostic.

MRI T1-Weighted Fat Segmentation Based on Active Contour for Osteosarcoma Patients

Osteosarcoma (OS) is the most common and frequent primary bone cancer in children and adolescents. This type of bone cancer often developed at the long bones’ extremities close to the metaphyseal growth plates. To address these issues, OS quantitative analysis is performed using Magnetic Resonance Imaging (MRI) to plan surgical procedures and track the effectiveness of treatment. Fat suppression is commonly employed to eliminate the fat signal from T1-Weighted MRI sequence. The suppressed fat signal in T1-Weighted is important and often used to identify abnormalities in other MRI sequences. In clinical, MRI images must be interpreted by a radiologist. Manually outlining the tumour location is laborious and subjective. Image processing involves segmentation to separate information from the desired target region of the image. Active Contour (AC) is an algorithm often used in medical images for segmentation. Nevertheless, the process of mask initialization can be challenging and requires careful attention. This study proposes a method to define the mask initialization so that the AC has a starting point to extract fat in T1-Weighted for the purpose of fat suppression. From the results obtained, AC with the proposed mask initialization method successfully segmented the fat in T1-Weighted MRI images with accuracy, precision, recall and F1-score of 0.92, 0.86, 0.88 and 0.89 respectively.

Advantages of cone beam computed tomography for evaluation of subchondral insufficiency fractures of the knee compared to MRI

To determine the diagnostic yield of cone beam computed tomography (CBCT) compared with 3 T magnetic resonance imaging (MRI) for the evaluation of subchondral insufficiency fractures of the knee. Consecutive patients with subchondral insufficiency fractures of the knee examined by 3 T MRI and CBCT of the femoral condyles were reviewed. Two experienced raters graded the lesion severity on 3 T MRI and CBCT images: grade 1: no signs of a subchondral bone lesion; grade 2: subchondral trabecular fracture or cystic changes, but without infraction of the subchondral bone plate; grade 3: collapse of the subchondral bone plate. Ratings were repeated after six weeks to determine reliability. In addition, the bone lesion size was measured as elliptical area (mm2) and compared between CBCT and T1-weighted MRI sequences. Among 30 patients included (43.3% women; mean age: 60.9 ± 12.8 years; body mass index (BMI) 29.0 ± 12.8 kg/m2), the medial femoral condyle was affected in 21/30 patients (70%). The grading of subchondral lesions between MRI and CBCT did not match in 12 cases (40%). Based on MRI images, an underestimation (i.e., undergrading) compared with CBCT was observed in nine cases (30%), whereas overgrading occurred in three cases (10%). Compared to CBCT, routine T1-weighted 3 T sequences significantly overestimated osseus defect zones in sagittal (84.7 ± 68.9 mm2 vs. 35.9 ± 38.2 mm2, p < 0.01, Cohen’s d = 1.14) and coronal orientation (53.1 ± 24.0 mm2 vs. 22.0 ± 15.2 mm2, p < 0.01, Cohen’s d = 1.23). The reproducibility of the grading determined by intra- and inter-rater agreement was very high in MRI (intra-class correlation coefficient (ICC) 0.78 and 0.90, respectively) and CBCT (ICC 0.96 and 0.96, respectively). In patients with subchondral insufficiency fractures of the knee, the use of CBCT revealed discrepancies in lesion grading compared with MRI. These findings are clinically relevant, as precise determination of subchondral bone plate integrity may influence the decision about conservative or surgical treatment. CBCT represents our imaging modality of choice for grading the lesion and assessing subchondral bone plate integrity. MRI remains the gold standard modality to detect especially early stages.

Poster 267: Relationship Between Sagittal Tibial Tubercle-Trochlear Groove Distance and Outcomes Following Cartilage Restoration for Patellofemoral Articular Cartilage Lesions

Objectives: Increased contact force in the patellofemoral (PF) joint is a known contributor to cartilage damage and pain. A tibial tubercle that is posterior to the trochlear groove may lead to aberrant loading and cartilage wear. The sagittal tibial-tubercle trochlear groove distance (sTT-TG), defined as the distance between the nadir of the trochlear groove and the most anterior aspect of the tibial tubercle, aids in quantifying the degree of risk of acquiring new lesions. However, the relationship between sTT-TG and patient-reported outcomes following surgery has not been assessed. Therefore, the purpose of this study is to assess the association between sTT-TG and post-operative outcomes in patients undergoing cartilage restoration procedures for PF articular cartilage lesions. Methods: A retrospective review of patients who underwent osteochondral allograft (OCA) transplantation or autologous chondrocyte implantation (ACI) at a single academic institution from 2010 to 2020 was conducted. Patients were included they underwent OCA or ACI for a high-grade (Outerbridge 3 or 4) articular cartilage lesion located in the patellofemoral joint (unipolar or bipolar), if they were between 18 and 50 years of age at the time of surgery, had magnetic resonance imaging (MRI) available, and had a minimum 2-year clinical follow-up. Demographic data such as age, sex, body mass index (BMI), as well as defect characteristics including size, number, and grade were collected. Before surgery, sTT-TG distance was measured independently on axial T2-weighted MRI sequences by two raters (Rater A and Rater B). Both raters measured the sTT-TG for the entire cohort at two different time points with a two-week time interval between each rater’s initial and follow-up measurements. The Interclass Coefficient (ICC) using a single measure, absolute agreement, two-way mixed effects model was used to test the intra-rater reliability of Rater A and Rater B; mean measures were used to assess the inter-rater reliability for the combined mean of the two rater’s measurements. Patients were surveyed to assess pain and satisfaction on a Visual Analog Scale (VAS) from 0 to 100. Functional outcomes were collected using the Knee Injury and Osteoarthritis Outcome Score (KOOS). The rate of return to sports, complications, and graft failure were also recorded [JT1]. An independent samples t-test was used to compare lesion size between the OCA and ACI group. Linear and logistic regression models accounting for age, sex, BMI, and sTT-TG distance were used to assess the relationship between sTT-TG and PROs. Results: A total of 76 patients, mostly female (61.8%), with a mean age of 31.9 ± 8.3 years, BMI of 26.8, and 60.6 ± 23.6-month follow-up were included. There were 37 (48.7%) patients that underwent OCA transplantation and 39 (51.3%) that underwent ACI. A total of 98 lesions were identified, with the majority (n = 93, 94.9%) being Grade 4. Overall, 54 patients had unipolar lesions and 22 had bipolar lesions. The mean defect size was 2.9 ± 1.4 cm2 and 3.5 ± 2.9 cm2 for the OCA and ACI groups (p = 0.459), respectively, with an overall mean lesion area of 3.2 ± 2.3 cm2. Intra-rater reliability for sTT-TG measurements at each time point was excellent for Rater A (ICC of 0.99 [0.986-0.994] p&lt;0.001) and Rater B (ICC of 0.99 [0.985-0.994]). Inter-rater reliability was excellent (ICC of 0.97 [0.955-.982] p&lt;0.001), with an overall mean sTT-TG of -4.98 ± 4.93 mm (range: -18.9, 5.7). On average, 48.7% (n = 37) of patients returned to sport and of those, 22.4% (n=17) returned to a similar or higher level of sport activity. Mean pain and satisfaction were 26.7 ± 25.1 and 73.8 ± 27.7, respectively. Collectively, the mean KOOS subscores were - KOOS symptoms: 71.4 ± 2.3, KOOS pain: 79.5 ± 2.0, KOOS sport: 60.2 ± 2.8, and KOOS QoL: 52.0 ± 2.6. When controlling for age, sex, BMI, and follow-up, sTT-TG was not predictive of RTS (p=0.706), pain (p=0.698), satisfaction (0.757), or any KOOS subscore (p&gt;0.05). Although, older age was associated with worse satisfaction (-0.819, 95% CI [-1.608,-0.03] and inferior KOOS pain (-0.606, 95% CI [-1.096,-0.116]), KOOS sport (-0.739, 95% CI [-1.445,-0.032]), and KOOS QoL (-0.786, 95% CI [-1.455,-0.117] p&lt;0.05). Conclusions: In this cohort of patients that underwent an OCA or ACI for PF cartilage lesions, sTT-TG was not predictive of post-operative patient reported functional outcomes or complications. These findings suggest that while a more posterior tibial tubercle (negative sTT-TG) may contribute to a higher incidence of cartilage pathology, patients can have favorable short-term outcomes following cartilage restoration with OCA or ACI.

Optimising needle depth in temporomandibular joint arthrocentesis: a magnetic resonance-based study for safety and efficacy

The aim of this paper was to determine the optimal needle depth for temporomandibular joint (TMJ) arthrocentesis using magnetic resonance imaging (MRI), with the aim of improving procedural safety and efficacy in clinical practice. A retrospective analysis of 264 TMJ MRIs from 132 patients at Istanbul Medipol Mega University Hospital was conducted. T2-weighted MRI sequences were utilised to measure distances from skin to joint capsules at varying needle entry points, applying the double puncture technique. The study adhered to ethical standards with appropriate approvals. The analysis revealed significant gender-related variations in needle depths (females showing shorter distances than males, p<0.05). No significant gender differences were found in condylar angles. An inverse correlation between age and condylar angle suggested age-related anatomical changes. Crucially, a 20 mm needle depth was identified as safer and more effective than the previously recommended 25 mm. This study underscores the necessity of revising needle depth to 20mm in TMJ arthrocentesis. These findings hold significant implications for improving procedural safety and catering to demographic variations.

A Novel Positive-Contrast Magnetic Resonance Imaging Line Marker for High-Dose-Rate (HDR) MRI-Assisted Radiosurgery (MARS).

Magnetic resonance imaging (MRI) can facilitate accurate organ delineation and optimal dose distributions in high-dose-rate (HDR) MRI-Assisted Radiosurgery (MARS). Its use for this purpose has been limited by the lack of positive-contrast MRI markers that can clearly delineate the lumen of the HDR applicator and precisely show the path of the HDR source on T1- and T2-weighted MRI sequences. We investigated a novel MRI positive-contrast HDR brachytherapy or interventional radiotherapy line marker, C4:S, consisting of C4 (visible on T1-weighted images) complexed with saline. Longitudinal relaxation time (T1) and transverse relaxation time (T2) for C4:S were measured on a 1.5 T MRI scanner. High-density polyethylene (HDPE) tubing filled with C4:S as an HDR brachytherapy line marker was tested for visibility on T1- and T2-weighted MRI sequences in a tissue-equivalent female ultrasound training pelvis phantom. Relaxivity measurements indicated that C4:S solution had good T1-weighted contrast (relative to oil [fat] signal intensity) and good T2-weighted contrast (relative to water signal intensity) at both room temperature (relaxivity ratio > 1; r2/r1 = 1.43) and body temperature (relaxivity ratio > 1; r2/r1 = 1.38). These measurements were verified by the positive visualization of the C4:S (C4/saline 50:50) HDPE tube HDR brachytherapy line marker on both T1- and T2-weighted MRI sequences. Orientation did not affect the relaxivity of the C4:S contrast solution. C4:S encapsulated in HDPE tubing can be visualized as a positive line marker on both T1- and T2-weighted MRI sequences. MRI-guided HDR planning may be possible with these novel line markers for HDR MARS for several types of cancer.

Differentiation of hemispheric white matter lesions in migraine and multiple sclerosis with similar radiological features using advanced MRI.

White matter hyperintensities (WMHs), presented on T2-weighted or fluid-attenuated inversion recovery magnetic resonance imaging (MRI) sequences, are lesions in the human brain that can be observed in both migraine and multiple sclerosis (MS). Seventeen migraine patients and 15 patients with relapsing-remitting multiple sclerosis with WMHs, and 17 healthy subjects age-and sex-matched to the migraine group were prospectively enrolled and underwent conventional and advanced MRI studies with diffusion-and perfusion-weighted imaging and single voxel proton magnetic resonance spectroscopy. In both disease groups, elevated T2 relaxation time, apparent diffusion coefficient (ADC) values, and decreased N-acetyl-aspartate levels were found in the intralesional white matter compared to the contralateral normal-appearing white matter (NAWM), while there was no difference between the hemispheres of the control subjects. Migraine patients had the lowest intralesional creatine + phosphocreatine and myo-inositol (mI) values among the three groups, while patients with MS showed the highest intralesional T1 and T2 relaxation times, ADC, and mI values. In the contralateral NAWM, the same trend with mI changes was observed in migraineurs and MS patients. No differences in perfusion variables were observed in any groups. Our multimodal study showed that tissue damage is detectable in both diseases. Despite the differences in various advanced MRI measures, with more severe injury detected in MS lesions, we could not clearly differentiate the two white matter lesion types.

CT-like images based on T1-weighted gradient echo MRI sequences for the assessment of fractures of the hand and wrist compared to CT

ObjectiveTo evaluate the performance of a 3D T1-weighted gradient-echo (3D T1GRE) computed tomography (CT)-like magnetic resonance imaging (MRI) sequence for detecting and assessing wrist and hand fractures compared to conventional CT.MethodsSubjects with acute wrist or hand fracture in CT underwent additional 3 T MRI including a CT-like 3D T1GRE sequence and were compared to patients without fractures. Two radiologists assessed fracture morphology on both modalities according to the Arbeitsgemeinschaft Osteosynthese (AO) and graded image quality and diagnostic confidence on a 5-point Likert scale.Besides diagnostic test evaluation, differences in image quality and diagnostic confidence between CT-like MRI and CT were calculated using the Wilcoxon test. Agreement of AO classification between modalities and readers was assessed using Cohen’s Kappa.ResultsTwenty-eight patients with 43 fractures and 43 controls were included. Image quality (3D T1GRE 1.19 ± 0.37 vs. CT 1.22 ± 0.42; p = 0.65) and diagnostic confidence (3D T1GRE 1.28 ± 0.53 vs. CT 1.28 ± 0.55; p = 1.00) were rated excellent for both modalities. Regarding the AO classification, intra- (rater 1 and rater 2, κ = 0.89; 95% CI 0.80–0.97) and interrater agreement were excellent (3D T1GRE, κ = 0.82; 95% CI, 0.70–0.93; CT, κ = 0.85; 95% CI, 0.75–0.94). CT-like MRI showed excellent sensitivity, specificity and accuracy for fracture detection (reader 1: 1.00, 0.92, 0.96; reader 2: 0.98, 0.94, 0.96).ConclusionCT-like MRI is a comparable alternative to CT for assessing hand and wrist fractures, offering the advantage of avoiding radiation exposure.

Improving portable low-field MRI image quality through image-to-image translation using paired low- and high-field images

Low-field portable magnetic resonance imaging (MRI) scanners are more accessible, cost-effective, sustainable with lower carbon emissions than superconducting high-field MRI scanners. However, the images produced have relatively poor image quality, lower signal-to-noise ratio, and limited spatial resolution. This study develops and investigates an image-to-image translation deep learning model, LoHiResGAN, to enhance the quality of low-field (64mT) MRI scans and generate synthetic high-field (3T) MRI scans. We employed a paired dataset comprising T1- and T2-weighted MRI sequences from the 64mT and 3T and compared the performance of the LoHiResGAN model with other state-of-the-art models, including GANs, CycleGAN, U-Net, and cGAN. Our proposed method demonstrates superior performance in terms of image quality metrics, such as normalized root-mean-squared error, structural similarity index measure, peak signal-to-noise ratio, and perception-based image quality evaluator. Additionally, we evaluated the accuracy of brain morphometry measurements for 33 brain regions across the original 3T, 64mT, and synthetic 3T images. The results indicate that the synthetic 3T images created using our proposed LoHiResGAN model significantly improve the image quality of low-field MRI data compared to other methods (GANs, CycleGAN, U-Net, cGAN) and provide more consistent brain morphometry measurements across various brain regions in reference to 3T. Synthetic images generated by our method demonstrated high quality both quantitatively and qualitatively. However, additional research, involving diverse datasets and clinical validation, is necessary to fully understand its applicability for clinical diagnostics, especially in settings where high-field MRI scanners are less accessible.

Examining the Role of Paraspinal Musculature in Postoperative Disability After Lumbar Fusion Surgery for Degenerative Spondylolisthesis.

Retrospective analysis of prospectively enrolled patients. To evaluate the relationship between paraspinal muscle (PM) atrophy and Oswestry Disability Index (ODI) improvement after spinal fusion surgery for degenerative lumbar spondylolisthesis. Atrophy of the PM is linked to multiple spinal conditions, sagittal malalignment, and increased postoperative complications. However, only limited evidence for the effect on patient-reported outcomes exists. Patients with degenerative lumbar spondylolisthesis undergoing decompression and fusion surgery were analyzed. Patients with missing follow-up, no imaging, or inadequate image quality were excluded. The ODI was assessed preoperatively and two years postoperatively. A cross-sectional area of the PM was measured on a T2-weighted magnetic resonance imaging sequence at the upper endplate of L4. On the basis of the literature, a 10-point improvement cutoff was defined as the minimum clinically important difference. Patients with a baseline ODI below the minimum clinically important difference were excluded. Logistic regression was used to calculate the association between fatty infiltration (FI) of the PM and improvement in ODI, adjusted for age, sex, and body mass index. A total of 133 patients were included in the final analysis, with only two lost to follow-up. The median age was 68 years (IQR 62-73). The median preoperative ODI was 23 (IQR 17-28), and 76.7% of patients showed improvement in their ODI score by at least 10 points. In the multivariable regression, FI of the erector spinae and multifidus increased the risk of not achieving clinically relevant ODI improvement ( P =0.01 and <0.001, respectively). No significant association was found for the psoas muscle ( P =0.158). This study demonstrates that FI of the erector spinae and multifidus is significantly associated with less likelihood of clinically relevant ODI improvement after decompression and fusion. Further research is needed to assess the effect of interventions.

Intracranial Arachnoiditis and Hydrocephalus

A 62-year-old man presented a diffuse and predominantly cisternal acute nonaneurysmal subarachnoid hemorrhage associated with hydrocephalus. An external ventricular drain was placed, followed by clinical deterioration after its removal. At this point, a heavily T2-weighted high-resolution sequence of a brain magnetic resonance imaging showed acute hydrocephalus recrudescence and multiple arachnoid adhesions in the supravermian and interpeduncular cisterns, creating a loculated/cystic appearance. The diagnosis of intracranial arachnoiditis was made. Intracranial arachnoiditis results from meningeal inflammation. Fibrosis and adhesions at the subarachnoid spaces may follow, restricting cerebrospinal fluid circulation, particularly at the cranial base. Hydrocephalus probably resulted from the combination of subarachnoid hemorrhage and extensive scaring at the basal cisterns, precluding transdural and transvenous cerebrospinal fluid efflux. Heavily T2-weighted high-resolution magnetic resonance imaging sequences allow an exquisite depiction of arachnoiditis, displaying obstructive cisternal membranes, and contribute to better etiologic assessment and management of hydrocephalus.

Imaging evaluation of a proposed 3D generative model for MRI to CT translation in the lumbar spine

A computed tomography (CT) and magnetic resonance imaging (MRI) are used routinely in the radiologic evaluation and surgical planning of patients with lumbar spine pathology, with the modalities being complimentary. We have developed a deep learning algorithm which can produce 3D lumbar spine CT images from MRI data alone. This has the potential to reduce radiation to the patient as well as burden on the health care system. The purpose of this study is to evaluate the accuracy of the synthetic lumbar spine CT images produced using our deep learning model. A training set of 400 unpaired CTs and 400 unpaired MRI scans of the lumbar spine was used to train a supervised 3D cycle-Gan model. Evaluators performed a set of clinically relevant measurements on 20 matched synthetic CTs and true CTs. These measurements were then compared to assess the accuracy of the synthetic CTs. The evaluation data set consisted of 20 patients who had CT and MRI scans performed within a 30-day period of each other. All patient data was deidentified. Notable exclusions included artefact from patient motion, metallic implants or any intervention performed in the 30 day intervening period OUTCOME MEASURES: The outcome measured was the mean difference in measurements performed by the group of evaluators between real CT and synthetic CTs in terms of absolute and relative error. Data from the 20 MRI scans was supplied to our deep learning model which produced 20 "synthetic CT" scans. This formed the evaluation data set. Four clinical evaluators consisting of neurosurgeons and radiologists performed a set of 24 clinically relevant measurements on matched synthetic CT and true CTs in 20 patients. A test set of measurements were performed prior to commencing data collection to identify any significant interobserver variation in measurement technique. The measurements performed in the sagittal plane were all within 10% relative error with the majority within 5% relative error. The pedicle measurements performed in the axial plane were considerably less accurate with a relative error of up to 34%. The computer generated synthetic CTs demonstrated a high level of accuracy for the measurements performed in-plane to the original MRIs used for synthesis. The measurements performed on the axial reconstructed images were less accurate, attributable to the images being synthesized from nonvolumetric routine sagittal T1-weighted MRI sequences. It is hypothesized that if axial sequences or volumetric data were input into the algorithm these measurements would have improved accuracy.

Automated Radiomic Analysis of Vestibular Schwannomas and Inner Ears Using Contrast-Enhanced T1-Weighted and T2-Weighted Magnetic Resonance Imaging Sequences and Artificial Intelligence.

To objectively evaluate vestibular schwannomas (VSs) and their spatial relationships with the ipsilateral inner ear (IE) in magnetic resonance imaging (MRI) using deep learning. Cross-sectional study. A total of 490 adults with VS, high-resolution MRI scans, and no previous neurotologic surgery. MRI studies of VS patients were split into training (390 patients) and test (100 patients) sets. A three-dimensional convolutional neural network model was trained to segment VS and IE structures using contrast-enhanced T1-weighted and T2-weighted sequences, respectively. Manual segmentations were used as ground truths. Model performance was evaluated on the test set and on an external set of 100 VS patients from a public data set (Vestibular-Schwannoma-SEG). Dice score, relative volume error, average symmetric surface distance, 95th-percentile Hausdorff distance, and centroid locations. Dice scores for VS and IE volume segmentations were 0.91 and 0.90, respectively. On the public data set, the model segmented VS tumors with a Dice score of 0.89 ± 0.06 (mean ± standard deviation), relative volume error of 9.8 ± 9.6%, average symmetric surface distance of 0.31 ± 0.22 mm, and 95th-percentile Hausdorff distance of 1.26 ± 0.76 mm. Predicted VS segmentations overlapped with ground truth segmentations in all test subjects. Mean errors of predicted VS volume, VS centroid location, and IE centroid location were 0.05 cm 3 , 0.52 mm, and 0.85 mm, respectively. A deep learning system can segment VS and IE structures in high-resolution MRI scans with excellent accuracy. This technology offers promise to improve the clinical workflow for assessing VS radiomics and enhance the management of VS patients.

3D zero-echo time and 3D T1-weighted gradient-echo MRI sequences as an alternative to CT for the evaluation of the lumbar facet joints and lumbosacral transitional vertebrae.

Computed tomography (CT) is the reference standard for assessment of the bone. Magnetic resonance imaging (MRI) developments enable a CT-like visualization of the osseous structures. To assess the diagnostic performance of 3D zero-echo time (3D-ZTE) and 3D T1-weighted gradient-echo (3D-T1GRE) MRI sequences for the evaluation of lumbar facet joints (LFJs) and the detection of lumbosacral transitional vertebrae (LSTV) using CT as the reference standard. In total, 87 adult patients were included in this prospective study. Evaluation of degenerative changes of the facet joints at the L3/L4, L4/L5, and L5/S1 levels on both sides was performed by two readers using a 4-point Likert scale. LSTV were classified according to Castelvi et al. Image quality was quantitatively measured using the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Intra-reader, inter-reader, and inter-modality reliability were calculated using Cohen's kappa statistic. Intra-reader agreement for 3D-ZTE, 3D-T1GRE, and CT was 0.607, 0.751, and 0.856 and inter-reader agreement was 0.535, 0.563, and 0.599, respectively. The inter-modality agreement between 3D-ZTE and CT was 0.631 and between 3D-T1GRE and CT 0.665. A total of LSTV were identified in both MR sequences with overall comparable accuracy compared to CT. Mean SNR for bone, muscle, and fat was highest for 3D-T1GRE and mean CNR was highest for CT. 3D-ZTE and 3D-T1GRE MRI sequences can assess the LFJs and LSTV and may serve as potential alternatives to CT.

Spinal epidural tuberculoma with osseous involvement: illustrative case.

A tuberculosis infection of the central nervous system can present as a localized, intraspinal tuberculoma. These lesions may cause spinal cord compression requiring early identification and surgical decompression to limit deleterious neurological sequelae. A 28-year-old female with a history of opioid use disorder presented with low-back pain in the setting of trauma with progressive bilateral lower extremity radiculopathy and paraparesis. T1- and T2-weighted magnetic resonance imaging sequences of the spine demonstrated a heterogeneously hyperintense extra-axial epidural mass at T11 with mass effect. Biopsy of the lesion revealed benign soft tissue with necrosis and caseating granulomatous inflammation consistent with tuberculoma. The patient underwent laminectomy and debulking of mass for decompression and was subsequently began antitubercular treatment with good neurological outcome. To the best of the authors' knowledge, there are only a handful of microbiologically and radiographically confirmed cases of spinal epidural tuberculoma in English literature. These lesions are rare and difficult to clinically and radiographically characterize in the absence of systemic pulmonary TB symptoms. Tuberculoma is an important differential for a spinal epidural mass, particularly because resection with systemic antitubercular treatment results in symptom resolution.