Axial T2-weighted Magnetic Resonance Imaging Research Articles

A Nomogram for Predicting Late-Onset Neurological Deficits in the Natural Course of Kyphosis or Kyphoscoliosis.

Retrospective single-center comparative analysis. To develop a nomogram model for predicting late-onset neurological deficits (LONDs) in patients with kyphosis or kyphoscoliosis. Patients with kyphosis or kyphoscoliosis might suffer from LONDs, and surgical correction may improve neurological function. Nevertheless, there exists a significant gap in the identification of predictive factors for LONDs in these patients. A consecutive series of 244 patients with kyphosis or kyphoscoliosis who underwent corrective surgery between April 2010 and June 2024 were included in our study. Relevant measurements, including the Cobb angle, deformity angular ratio (DAR), and level of the apex were assessed and calculated using X-ray imaging. Spinal cord morphology at the apex of the major curve was evaluated using preoperative axial T2-weighted magnetic resonance imaging (MRI) to categorize patients into three types based on the spinal cord shape classification system (SCSCS). To identify independent risk factors associated with LONDs, we employed univariate analysis followed by backward stepwise multivariate logistic regression analysis. A nomogram was established based on the identified independent risk factors to predict the likelihood of LONDs in patients with kyphosis or kyphoscoliosis. The mean age of the 244 patients was 46.4±17.8 years, with an observed incidence of LONDs at 57.8%. The backward stepwise multivariate logistic regression analysis indicated that age, etiological diagnosis and SCSCS were independent predictors of LONDs. Utilizing these independent risk factors, we constructed a nomogram model to estimate the probability of LONDs. The concordance index (C-index) of the model was 0.912 (95% CI, 0.876-0.947), indicating a satisfactory level of accuracy in predicting the likelihood of LONDs. The predictive factors for LONDs include age, etiological diagnosis and SCSCS. We developed a nomogram model to predict LONDs, which could be useful for patient counseling and facilitating treatment-related decision-making.

Sex Differences in Fat Distribution and Muscle Fat Infiltration in the Lower Extremity: A Retrospective Diverse-Ethnicity 7T MRI Study in a Research Institute Setting in the USA.

Background: Fat infiltration in skeletal muscle is related to declining muscle strength, whereas excess subcutaneous fat is implicated in the development of metabolic diseases. Methods: Using multi-slice axial T2-weighted (T2w) MR images, this retrospective study characterized muscle fat infiltration (MFI) and fat distribution in the lower extremity of 107 subjects (64M/43F, age 11-79 years) with diverse ethnicities (including White, Black, Latino, and Asian subjects). Results: MRI data analysis shows that MFI, evaluated by the relative intensities of the pixel histogram profile in the calf muscle, tends to increase with both age and BMI. However, statistical significance was found only for the age correlation in women (p < 0.002), and the BMI correlation in men (p = 0.04). Sex disparities were also seen in the fat distribution, which was assessed according to subcutaneous fat thickness (SFT) and the fibula bone marrow cross-sectional area (BMA). SFT tends to decrease with age in men (p < 0.01), whereas SFT tends to increase with BMI only in women (p < 0.01). In contrast, BMA tends to increase with age in women (p < 0.01) and with BMI in men (p = 0.04). Additionally, MFI is positively correlated with BMA but not with SFT, suggesting that compromised bone structure may contribute to fat infiltration in the surrounding skeletal muscle. Conclusions: The findings of this study highlight a sex factor affecting MFI and fat distribution, which may offer valuable insights into effective strategies to prevent and treat MFI in women versus men.

Application of deep learning reconstruction in abdominal magnetic resonance cholangiopancreatography for image quality improvement and acquisition time reduction

PurposeTo compare deep learning (DL)-based and conventional reconstruction through subjective and objective analysis and ascertain whether DL-based reconstruction improves the quality and acquisition speed of clinical abdominal magnetic resonance imaging (MRI). MethodsThe 124 patients who underwent abdominal MRI between January and July 2021 were retrospectively studied. For each patient, two-dimensional axial T2-weighted single-shot fast spin-echo MRI images with or without fat saturation were reconstructed using DL-based and conventional methods. The subjective image quality scores and objective metrics, including signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the images were analysed. An explorative analysis was performed to compare 20 patients’ MRI images with site routine settings, high-resolution settings and high-speed settings. Paired t tests and Wilcoxon signed-rank tests were used for subjective and objective comparisons. ResultsA total of 144 patients were evaluated (mean age, 62.2 ± 14.1 years; 83 men). The MRI images reconstructed using DL-based methods had higher SNRs and CNRs than did those reconstructed using conventional methods (all p < 0.01). The subjective scores of the images reconstructed using DL-based methods were higher than those of the images reconstructed using conventional methods (p < 0.01), with significantly lower variation (p < 0.01). Exploratory analysis revealed that the DL-based reconstructions with thin slice thickness and higher temporal resolution had the highest image quality and were associated with the shortest scan times. ConclusionsDL-based reconstruction methods can be used to improve the quality with higher stability and accelerate the acquisition of abdominal MRI.

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.

Predictors of Hydrocephalus Risk After Stereotactic Radiosurgery for Vestibular Schwannomas: Utility of the Evans Index.

Hydrocephalus after Gamma Knife® stereotactic radiosurgery (SRS) for vestibular schwannomas is a rare but manageable occurrence. Most series report post-SRS communicating hydrocephalus in about 1% of patients, thought to be related to a release of proteinaceous substances into the cerebrospinal fluid. While larger tumor size and older patient age have been associated with post-SRS hydrocephalus, the influence of baseline ventricular anatomy on hydrocephalus risk remains poorly defined. A single-institution retrospective cohort study examining patients who developed symptomatic communicating hydrocephalus after undergoing Gamma Knife® SRS for unilateral vestibular schwannomas from 2011 to 2021 was performed. Patients with prior hydrocephalus and cerebrospinal fluid diversion or prior surgical resection were excluded. Baseline tumor volume, third ventricle width, and Evans Index (EI)-maximum width of the frontal horns of the lateral ventricles/maximum internal diameter of the skull-were measured on axial postcontrast T1-weighted magnetic resonance imaging. A total of 378 patients met the inclusion criteria; 14 patients (3.7%) developed symptomatic communicating hydrocephalus and 10 patients (2.6%) underwent shunt placement and 4 patients (1.1%) were observed with milder symptoms. The median age of patients who developed hydrocephalus was 69 years (IQR, 67-72) and for patients younger than age 65 years, the risk was 1%. For tumor volumes <1 cm3, the risk of requiring shunting was 1.2%. The odds of developing symptomatic hydrocephalus were 5.0 and 7.7 times higher in association with a baseline EI > 0.28 (P = .024) and tumor volume >3 cm3 (P = .007), respectively, in multivariate analysis. Fourth ventricle distortion on pre-SRS imaging was significantly associated with hydrocephalus incidence (P < .001). Patients with vestibular schwannoma with higher baseline EI, larger tumor volumes, and fourth ventricle deformation are at increased odds of developing post-SRS hydrocephalus. These patients should be counseled regarding risk of hydrocephalus and carefully monitored after SRS.

Study on the consistency between CT hounsfield units and MRI evaluation of preoperative cervical paraspinal muscular fat infiltration in patients undergoing ACDF

ObjectiveTo explore the feasibility of applying CT Hounsfield Units (HUs) for the assessment of preoperative paraspinal muscle fat infiltration (FI) in different segments in patients who underwent anterior cervical discectomy and fusion (ACDF). To compare the consistency of preoperative paraspinal muscle FI evaluations using MRI and those via CT HUs in patients who underwent ACDF surgery.MethodsNinety-five patients (45 males and 50 females, aged 37‒71 years) who received CT and MRI examinations and underwent ACDF surgery were retrospectively analyzed. In the axial T2-weighted MR images at the median level of the C3/4, C4/5, and C5/6 segments, regions of interests (ROIs) were delineated along the boundaries of the cervical multifidus (MF) and semispinalis cervicis (Scer) muscles. Using the threshold tool in ImageJ software, areas of fat tissue and intermuscular septa within the ROI were quantified. The effective cross-sectional area (ECSA) for each side was obtained by subtracting the areas of fat tissue and intermuscular septa from the total ROI area. The ratio of the fat tissue area to the CSA was then calculated to determine the initial FI value. The depth of subcutaneous fat from the midline spinous process to the epidermis at the median plane of the C4/5 intervertebral disc was measured. The initial FI values were then divided by the depth of fat to determine the post-correction FI value. Using the Picture Archiving and Communication System (PACS), at identical segments and planes, ROIs were delineated using the same method as in MRI under a standard soft tissue window (width of 500 HU, level of 60 HU). The CT HU values were measured within these defined areas. The CT HU values from both sides are summed to obtain the total HU value for the segment. According to whether the measurement results of two sets of data follow a normal distribution, Pearson’s test or Sperman’s test was used to analyze the correlation.ResultsOn MRI, a statistically significant difference was observed in the post-correction FI only at the C3/4 segment compared to the other two segments (P < 0.05). No significant difference in the post-correction FI between the C4/5 and C5/6 segments was noted (P > 0.05). The CT HU results showed a substantial discrepancy between C3/4 and C4/5 segments and between C3/4 and C5/6 segments (P < 0.05), whereas no statistically significant difference was found in the CT HU value between the C4/5 and C5/6 segments (P > 0.05). The consistency analysis revealed a relatively strong correlation between the post-correction FI and CT HU values of the C3/4 and C4/5 segments. Furthermore, a strong correlation was detected in the variations in the measurement outcomes at the C5/6 segment.ConclusionPatients requiring surgical treatment for the cervical spine exhibit varying degrees of FI in paraspinal muscles across different locations and segments. Evaluating the degree of FI in the paraspinal muscles of the cervical spine through CT HU values is feasible. There is considerable consistency between the post-correction FI assessed under MRI and the measurements of CT HU values in evaluating the FI of paraspinal muscles in the cervical spine.

Changes in Intramedullary Increased Signal Intensity on Axial T2-weighted MRI After Laminoplasty for Cervical Spondylotic Myelopathy: A 10-year Follow-up Study.

A retrospective study. To investigate whether the preoperative classification and changes in the intramedullary increased signal intensity (ISI) on axial T2-weighted magnetic resonance imaging (MRI) reflect the postoperative functional outcome in patients after laminoplasty for cervical spondylotic myelopathy (CSM). Although patients with CSM exhibit ISI on axial MRI, the association between ISI (preoperative classification and changes) and surgical outcomes has not been investigated. We retrospectively included patients with CSM who underwent MRI preoperatively and at least 10 years postoperatively after laminoplasty between January 2009 and December 2010. According to axial images for the cervical compressive myelopathy (Ax-CCM) system, the ISI on axial images was classified as follows: type 0, normal; type 1, diffuse; type 2, fuzzy focal; and type 3, discrete focal. Functional outcomes, as measured by the Japanese Orthopaedic Association (JOA) score and JOA recovery rate, were evaluated based on the Ax-CCM classification. Forty-three patients were enrolled. The mean follow-up time was 11.0±1.0 years. At the final follow-up, postoperative changes in the type of ISI were observed in 62.8% of patients. The type of ISI improved in 5 patients (11.6%), remained unchanged in 16 patients (37.2%), and worsened in 22 patients (51.2%). Patients with preoperative type 2 ISI had worse postoperative JOA scores and JOA recovery rates than those with other types. A worse ISI type was related to a lower postoperative JOA score and a lower recovery rate at the final follow-up. Type 2 ISI was associated with poor postoperative symptoms and low postoperative function improvement. ISI changed after laminoplasty in 27 patients (62.8%), and worsened ISI was related to poor surgical outcomes.

Automatically Detecting Pancreatic Cysts in Autosomal Dominant Polycystic Kidney Disease on MRI Using Deep Learning.

Pancreatic cysts in autosomal dominant polycystic kidney disease (ADPKD) correlate with PKD2 mutations, which have a different phenotype than PKD1 mutations. However, pancreatic cysts are commonly overlooked by radiologists. Here, we automate the detection of pancreatic cysts on abdominal MRI in ADPKD. Eight nnU-Net-based segmentation models with 2D or 3D configuration and various loss functions were trained on positive-only or positive-and-negative datasets, comprising axial and coronal T2-weighted MR images from 254 scans on 146 ADPKD patients with pancreatic cysts labeled independently by two radiologists. Model performance was evaluated on test subjects unseen in training, comprising 40 internal, 40 external, and 23 test-retest reproducibility ADPKD patients. Two radiologists agreed on 52% of cysts labeled on training data, and 33%/25% on internal/external test datasets. The 2D model with a loss of combined dice similarity coefficient and cross-entropy trained with the dataset with both positive and negative cases produced an optimal dice score of 0.7 ± 0.5/0.8 ± 0.4 at the voxel level on internal/external validation and was thus used as the best-performing model. In the test-retest, the optimal model showed superior reproducibility (83% agreement between scan A and B) in segmenting pancreatic cysts compared to six expert observers (77% agreement). In the internal/external validation, the optimal model showed high specificity of 94%/100% but limited sensitivity of 20%/24%. Labeling pancreatic cysts on T2 images of the abdomen in patients with ADPKD is challenging, deep learning can help the automated detection of pancreatic cysts, and further image quality improvement is warranted.

A Characteristic Magnetic Resonance Imaging Finding to Identify Morton Neuroma: The Slug Sign.

Morton neuroma is a common cause of forefoot pain and sensory disturbances, but it is difficult to identify on magnetic resonance imaging (MRI). The aim of this study was to verify the usefulness of a characteristic MRI finding (slug sign) for identifying Morton neuroma and to clarify the relationship between excised neuroma characteristics and preoperative MRI findings. Twenty-two web spaces were retrospectively assessed from the second and third intermetatarsal spaces of 11 feet of 10 patients (7 women and 3 men, aged average 59.5 years) who underwent surgical excision of Morton neuroma between 2017 and 2022. Asymptomatic web spaces were used as control. Neuromas with 2 branches of the plantar digital nerves on axial T1-weighted MRI (MRI-T1WI) were considered the slug sign. We investigated the preoperative presence of the slug sign in Morton neuroma and asymptomatic control web spaces. We also investigated the relationship between the maximum transverse diameter of the excised specimen and that estimated on coronal MRI-T1WI. A total of 15 Morton neuromas were excised and assessed. The slug signs were present in 10 intermetatarsal spaces in 15 web spaces with Morton neuroma whereas the sign was found in 1 intermetatarsal space in 7 asymptomatic web spaces. The sensitivity and specificity for the slug sign to diagnose Morton neuroma was 66.7% and 85.7%, respectively. The positive and negative predictive values were 90.9% and 54.5%, respectively. The mean maximum transverse diameter of excised neuromas was 4.7 mm. The mean maximum transverse diameter of neuromas on coronal MRI-T1WI was 3.4 mm. A significant positive correlation was found between the maximum transverse diameters of excised specimens and diameters estimated on coronal MRI-T1WI (r = 0.799, P < .001). The slug sign may be a useful indicator of Morton neuroma on MRI to confirm nerve involvement after bifurcation. Level IV, retrospective series.

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.

Relationship between facet joint osteoarthritis and lumbar paraspinal muscle atrophy: a cross-sectional study.

The paraspinal muscles play an essential role in the stabilization of the lumbar spine. Lumbar paraspinal muscle atrophy has been linked to chronic back pain and degenerative processes within the spinal motion segment. However, the relationship between the different paraspinal muscle groups and facet joint osteoarthritis (FJOA) has not been fully explored. In this cross-sectional study, the authors analyzed adult patients who underwent lumbar spinal surgery between December 2014 and March 2023 for degenerative spinal conditions and had preoperative MRI and CT scans. The fatty infiltration (FI) and functional cross-sectional area (fCSA) of the psoas, erector spinae, and multifidus muscles were assessed on axial T2-weighted MR images at the level of the upper endplate of L4 based on established studies and calculated using custom-made software. Intervertebral disc degeneration at each lumbar level was evaluated using the Pfirrmann grading system. The grades from each level were summed to report the cumulative lumbar Pfirrmann grade. Weishaupt classification (0-3) was used to assess FJOA at all lumbar levels (L1 to S1) on preoperative CT scans. The total lumbar FJOA score was determined by adding the Weishaupt grades of both sides at all 5 levels. Correlation and linear regression analyses were conducted to assess the relationship between FJOA and paraspinal muscle parameters. A total of 225 patients (49.7% female) with a median age of 61 (IQR 54-70) years and a median BMI of 28.3 (IQR 25.1-33.1) kg/m2 were included. After adjustment for age, sex, BMI, and the cumulative lumbar Pfirrmann grade, only multifidus muscle fCSA (estimate -4.69, 95% CI -6.91 to -2.46; p < 0.001) and FI (estimate 0.64, 95% CI 0.33-0.94; p < 0.001) were independently predicted by the total FJOA score. A similar relation was seen with individual Weishaupt grades of each lumbar level after controlling for age, sex, BMI, and the Pfirrmann grade of the corresponding level. Atrophy of the multifidus muscle is significantly associated with FJOA in the lumbar spine. The absence of such correlation for the erector spinae and psoas muscles highlights the unique link between multifidus muscle quality and the degeneration of the spinal motion segment. Further research is necessary to establish the causal link and the clinical implications of these findings.

Contrast-enhanced pelvic magnetic resonance imaging (MRI) for the prediction of treatment response in mucinous rectal cancer.

In mucinous rectal cancer, it can be difficult to differentiate between cellular and acellular mucin. The purpose of this study was to evaluate, in patients with mucinous rectal cancer, the value of static enhancement (enh) and pharmacokinetic parameters of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in predicting pathologic complete response. This retrospective cross-sectional study performed at Memorial Sloan Kettering Cancer Center included 43 patients (24 males and 19 females; mean age, 57 years) with mucinous rectal cancer who underwent MRI at baseline as well as after neoadjuvant chemoradiotherapy but before surgical resection between 2008 and 2019. Two radiologists independently segmented tumors on contrast-enhanced axial 3D T1-weighted images and sagittal DCE magnetic resonance images. On contrast-enhanced axial T1-weighted images, the static parameters enh and relative enhancement (renh) were estimated. On DCE images, the pharmacokinetic parameters Ktrans, kep, relative Ktrans (rKtrans), and relative kep (rkep) were estimated. Associations between all parameters with pathologic complete response were tested using Wilcoxon signed-rank tests. Receiver operating characteristic (ROC) analysis was performed to assess the area under the curve (AUC) for each parameter. Of the 43 patients who were included in the study, 42/43 (98%) had evaluable contrast-enhanced axial T1-weighted images and 35/43 (81%) had evaluable DCE images. Of the patients with evaluable contrast-enhanced axial T1-weighted images, 9/42 (21%) had pathologic complete response and 33/42 (79%) did not have pathologic complete response. For reader 1, enh(pre-neoadjuvant chemotherapy), enh(post-neoadjuvant chemotherapy), and renh were significant predictors of pathologic complete response [P=0.045 (AUC =0.73), 0.039 (AUC =0.74), and 0.0042, respectively]. For reader 2, enh(pre-neoadjuvant chemotherapy) and renh were significant predictors [P=0.021 (AUC =0.77) and 0.002, respectively]. For renh, the AUC was 0.83 for reader 1, and 0.82 for reader 2. Meanwhile, of those patients with evaluable DCE images, 9/35 (26%) had pathologic complete response and 26/35 (74%) did not have pathologic complete response. Ktrans(pre-neoadjuvant chemotherapy), kep(pre-neoadjuvant chemotherapy), and rkep were significant predictors [P=0.016 (AUC =0.73), 0.00057 (AUC =0.81), and 0.0096 (AUC =0.74), respectively]. Static and pharmacokinetic parameters of contrast-enhanced MRI show promise to predict neoadjuvant treatment response. Static enh parameters, which are simpler to assess, showed the strongest prediction.

Prospective Validation of the Spinal Cord Shape Classification System in the Prediction of Intraoperative Neuromonitoring Data Loss: Assessing the Risk of Spinal Cord Data Loss During Spinal Deformity Correction.

The Spinal Cord Shape Classification System (SCSCS) class has been associated with spinal cord monitoring data loss during spinal deformity surgery. The objective of the current study was to prospectively validate the SCSCS as a predictor of spinal cord monitoring data loss during spinal deformity surgery. A prospective cohort study of consecutive patients who were undergoing primary deformity surgery at a single institution from 2018 to 2023 and whose major curve was in the spinal cord region was undertaken. Spinal cord morphology at the apex of the major curve on preoperative axial T2-weighted magnetic resonance imaging was used to categorize patients into 3 spinal cord shape types based on the SCSCS. The primary outcome was intraoperative neuromonitoring (IONM) data loss related to spinal cord dysfunction. Demographics and surgical and radiographic variables were compared between patients with IONM data loss and those without loss. Predictors of IONM loss were determined using bivariate and multivariable logistic regression analyses. A total of 256 patients (168 adult, 88 pediatric) were included and were separated into 3 SCSCS types: 110 (43.0%) with Type I, 105 (41.0%) with Type II, and 41 (16.0%) with Type III. IONM loss was observed in 30 (11.7%) of the 256 patients, including 7 (6.4%) of 110 with SCSCS Type I, 7 (6.7%) of 105 with Type II, and 16 (39.0%) of 41 with Type III. IONM loss was associated with SCSCS Type III, the preoperative deformity angular ratio, performance of 3-column osteotomies, greater operative time, greater transfusion volume, and greater postoperative sagittal corrections. SCSCS type was the strongest independent predictor of IONM data loss. SCSCS Type III had the greatest odds of IONM loss (odds ratio [OR] = 6.68, 95% confidence interval [CI] = 2.45 to 18.23 compared with Types I and II combined). The overall predictive performance with respect to IONM loss (area under the receiver operating characteristic curve = 0.827) was considered excellent. This prospective cohort study of patients undergoing spinal deformity correction confirmed that patients with a Type-III spinal cord shape had greater odds of IONM loss. Inclusion of the SCSCS in preoperative risk stratification and intraoperative management of spinal deformity corrective surgery is recommended. Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Degeneration of Cervical Multifidus Muscles Negatively Affects Physical Activity-related Quality of Life After Laminoplasty for Degenerative Cervical Myelopathy.

A retrospective cohort study. The study aimed to investigate the related factors affecting physical activity-related quality of life (QOL) after 2 years of cervical laminoplasty for degenerative cervical myelopathy (DCM), focusing on the degree of preoperative degeneration of the cervical multifidus muscles. The association between paraspinal muscle degeneration and clinical outcomes after spinal surgery is being investigated. The effect of preoperative degeneration of the cervical multifidus muscles in patients undergoing cervical laminoplasty is ambiguous. Patients who underwent laminoplasty for DCM and followed up for more than 2 years were reviewed. To evaluate physical QOL, the physical component summary (PCS) of the 36-Item Short-Form Health Survey (SF-36) was recorded at 2 years postoperatively. The degree of preoperative degeneration in the multifidus muscles at the C4 and C7 levels on axial T2-weighted magnetic resonance imaging (MRI) was categorized according to the Goutallier grading system. The correlation between 2-year postoperative PCS and each preoperative clinical outcome, radiographic parameter, and MRI finding, including Goutallier classification, was analyzed. Variables with a P value <0.10 in univariate analysis were included in multiple linear regression analysis. In total, 106 consecutive patients were included. The 2-year postoperative PCS demonstrated significant correlation with age ( R =-0.358, P =0.002), preoperative JOA score ( R =0.286, P =0.021), preoperative PCS ( R =0.603, P <0.001), C2-C7 lordotic angle ( R =-0.284, P =0.017), stenosis severity ( R =-0.271, P =0.019), and Goutallier classification at the C7 level ( R =-0.268, P =0.021). In multiple linear regression analysis, sex (β=-0.334, P =0.002), age (β=-0.299, P =0.013), preoperative PCS (β=0.356, P =0.009), and Goutallier classification at the C7 level (β=-0.280, P =0.018) were significantly related to 2-year postoperative PCS. Increased degeneration of the multifidus muscle at the C7 level negatively affected physical activity-related QOL postoperatively. These results may guide spine surgeons in predicting physical activity-related QOL in patients with DCM after laminoplasty. Level III.

The Success of Deep Learning Modalities in Evaluating Modic Changes

BackgroundModic changes are pathologies that are common in the population and cause low back pain. The aim of the study is to analyze the modic changes detected in magnetic resonance imaging (MRI) using deep learning modalities. MethodsThe sagittal T1, sagittal and axial T2-weighted lumbar MRI images of 307 patients, of which 125 were female and 182 were male, aged 19-86 years, who underwent MRI examination between 2016-2021 were analyzed. Modic changes (MC) were categorized and marked according to signal changes. Our study consists of two independent stages: classification and segmentation. The categorized data was first classified using convolutional neural network (CNN) architectures such as DenseNet-121, DenseNet-169, and VGG-19. In the next stage, masks were removed by segmentation using U-Net, which is the CNN architecture, with image processing programs on the marked images. ResultsDuring the classification stage, the success rates for modic type 1, type 2, and type 3 changes were 98%, 96%, 100% in DenseNet-121, 100%, 94%, 100% in DenseNet-169, and 98%, 92%, 97% in VGG-19, respectively. At the segmentation phase, the success rate was 71% with the U-Net architecture. ConclusionEvaluation of MRI findings of MC in the etiology of lower back pain with deep learning architectures can significantly reduce the workload of the radiologist by providing ease of diagnosis.

Normal diameter of the optic nerve using magnetic resonance imaging: A retrospective Nigerian study.

The variations in the diameter of the optic nerve (ON) are important clinically in the diagnosis of conditions associated with the ON such as raised intracranial pressure, meningioma, optic neuritis, and Grave's orbitopathy. This study determined the normal diameters of the ON in adult Nigerians seen in a Hospital in Delta State. Axial T1-weighted brain magnetic resonance imaging images of 150 patients (75 males and 75 females) aged ≥20 years were retrieved from the hospital's radiological database and retrospectively used to evaluate the diameter of the ON on axial and coronal sections. The data were analyzed and summarized using descriptive statistics. The mean diameters were compared based on gender, side, and age groups and correlated with age using inferential statistics. The significance level was considered at 5%. The diameter of the ON measured 0.45 ± 0.07 cm on the coronal section, besides 0.50 ± 0.07 cm, and 0.46 ± 0.06 cm at 0.3 cm and 0.8 cm from the posterior pole of the globe, respectively, on the axial slices. The diameters were significantly larger in males than in females (P < 0.05) and were symmetrical. However, they lacked significant association with age (P > 0.05). The three diameters measured had a significant positive correlation with each other (P < 0.05). The study provides a normal range of ON diameter in the study center to aid in the diagnosis of raised intracranial pressure and pathologies involving the nerve and its sheath.

An Expanded Surgical Corridor of Oblique Lateral Interbody Fusion at L4-5: A Magnetic Resonance Imaging Study.

We introduced a new preoperative method, the "expanded surgical corridor," to evaluate the actual safety corridor, which may expand the possibility of performing oblique lateral interbody fusion (OLIF). Axial T2-weighted magnetic resonance images at the L4-5 disc level of 511 lumbar degenerative disease patients was evaluated. The distance between the medial edge of the left-sided psoas muscle and the major artery was measured as the conventional surgical corridor (CSc). The distance between the major vein and lumbar plexus was measured as the expanded surgical corridor (ESc). The mean CSc and ESc were 13.9 ± 8.20 and 37.43 ± 10.1 mm, respectively. No surgical corridor was found in 7.05% of CSc and 1.76% of ESc, small corridor ( ≤ 1 cm) was found in 27.40% of CSc and 0.59% of ESc, moderate corridor (1-2 cm) was found in 42.07% of CSc and 1.96% of ESc, and large corridor ( > 2 cm) was found in 23.48% of CSc and 95.69% of ESc. A total of 33.83% (45 of 133) of whom were preoperatively categorized as having a limited surgical corridor by conventional measurement, underwent OLIF L4-5 successfully. By using the ESc, only 2.35% were categorized as having a limited surgical corridor. The other 97.65% of the patients had an approachable corridor that could be successfully operated by experienced spine surgeons who employ meticulous surgical dissection and thorough understanding of the anatomical structures. The ESc may represent true accessibility to the disc space for OLIF, particularly at the L4-5 level.

Unilateral transforaminal lumbar interbody fusion through a modified hemilateral spinous process-splitting approach.

To describe unilateral transforaminal lumbar interbody fusion (TLIF) via a modified hemilateral spinous process-splitting (MHSPS) approach and determine its effectiveness. Sixty-five consecutive patients with the lumbar degenerative disease who underwent MHSPS TLIF between August 2020 and July 2021 were retrospectively analyzed. Japanese Orthopedic Association (JOA) score and visual analog scale (VAS) scores for back and leg pain were evaluated before surgery and at the last follow-up. Postoperative paraspinal muscle atrophy was evaluated on axial T2-weighted magnetic resonance imaging. Mean JOA score increased from 13.6 ± 3.21 before surgery to 24.72 ± 3.34 at last follow-up (p < 0.001). The mean recovery rate was 68.2% ± 5.68%. Clinical outcome was excellent in 22, good in 35, and fair in 8 patients. The VAS score for low back pain was significantly lower at the last follow-up than before surgery (1.18 ± 0.99 vs. 3.09 ± 1.35; p < 0.001). The VAS score for leg pain was also significantly lower at the last follow-up than before surgery (1.13 ± 0.91 vs. 6.61 ± 1.23; p < 0.001). The mean paraspinal muscle atrophy rate did not significantly differ between the symptomatic side (6% ± 3.8%) and asymptomatic side (4.8% ± 3.3%) at last follow -up (p = 0.071). MHSPS TLIF is an effective minimally invasive surgical treatment for selected types of degenerative lumbar disease. This technique can achieve effective spinal decompression and interbody fusion. Its advantages include direct and adequate visualization, vast surgical working space, short operation time, and minimal muscle injury.

A correlation study of preoperative lumbar paraspinal muscle quality and L5-S1 lumbar foraminal stenosis degeneration after L4–5 TLIF

Study designThis was a retrospective study.ObjectivesAdjacent segment degeneration (ASD) is a major complication associated with spinal fusion. The lumbar paraspinal muscle is an essential factor influencing the occurrence of ASD. This study aimed to investigate the effect of preoperative lumbar paraspinal muscle quality on L5-S1 adjacent lumbar foraminal stenosis degeneration (ASLFSD) after L4–5 transforaminal lumbar interbody fusion (TLIF).MethodsA total of 113 patients diagnosed with lumbar spinal stenosis at L4–5 were treated with TLIF. Lumbar paraspinal muscle measurements were obtained preoperatively and bilaterally from axial T2-weighted MR images. The measurements included the total cross-sectional area of psoas (PS-tCSA), of erector spinae (ES-tCSA), and of multifidus (MF-tCSA); and fatty infiltration of psoas (PS-FI), of erector spinae (ES-FI), and of multifidus (MF-FI). Foraminal measurements, including posterior disc height (PDH), disc-to-facet distance (D–F), foraminal height (FH), and foraminal area (FA), were obtained bilaterally using a computed tomography system. The association between lumbar paraspinal muscle quality and changes in foraminal measurements was also studied.ResultsWe observed that the FH and FA significantly reduced at 1 year postoperatively at the mean follow-up period of 41.56 ± 8.38 months (range, 43–50 months), and PDH, D–F, FH, and FA all significantly reduced at final follow-up. These changes in foraminal measurements were significantly and negatively correlated with PS-FI, ES-FI, and MF-FI.ConclusionDuring the clinical follow-up, we found that patients with a higher degree of paraspinal muscle FI were more likely to develop L5-S1 ASLFSD after L4–5 TLIF.

P20.11.A TEMPORAL MUSCLE THICKNESS AS PROGNOSTIC MARKER IN PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA - A VALIDATION STUDY

Abstract BACKGROUND Primary central nervous system lymphoma (PCNSL) is a rare, aggressive diffuse large B-cell lymphoma, confined to the central nervous system. Age and performance status are validated prognostic variables in PCNSL. Frailty may also be a factor but is not easily quantified. Temporal muscle thickness (TMT), as parameter of sarcopenia, is believed to reflect frailty, is easily measurable and may be a valuable additional prognostic factor: mean TMT has been described as an independent prognostic factor in PCNSL patients. This study aims to validate these results in a prospective cohort. MATERIAL AND METHODS All patients from a large phase III trial (HOVON 105/ALLG NHL 24; EudraCT 2009-014722-42) of whom baseline axial T1 weighted magnetic resonance images (MRI) were available were included. Sarcopenia is defined as a mean TMT &amp;lt;6.3mm for men and &amp;lt;5.2mm for women, measured on axial T1-weighted MRI. The TMT was measured by a radiologist (RG) with and a neurologist (MvdM) without correction for angulation of images. Sarcopenia, together with known other prognostic factors were analyzed in a Cox-regression analysis for progression-free (PFS) and overall survival (OS) for both investigators. RESULTS TMT measurements were possible in 164/199 trial patients. The median mean TMT was 7.62mm (IQR: 6.58-9.00; measured by RG) and 5.94mm (IQR: 5.09-7.01; measured by MvdM). The mean TMT was not significantly different between those who used dexamethasone, and those who did not. Sarcopenia was present in 75 patients (46%), measured by MvdM without correction for angulation of the images and in 21 patients (13%), measured by RG with correction for angulation of the images. In univariate analyses, age (&amp;gt;60 years-old) and baseline Mini-Mental State Examination-score &amp;lt;27 were significantly associated with adverse PFS and OS. In multivariate analyses, only age remained as independent prognostic factor for adverse PFS and OS. Sarcopenia, as measured by either of the investigators, was not associated with survival. For measurements by RG, presumed to be most accurate, the Hazard Ratio (95% confidence interval) was 0.68 (0.33-1.40), p=0.30 for PFS, and HR (95% CI): 0.97 (0.42-2.20), p=0.93 for OS in the multivariate analysis. CONCLUSION There was a low interobserver agreement between a neurologist and a radiologist regarding TMT measurements, which questions the use of this parameter in daily practice by non-radiologists. Sarcopenia, based on the mean TMT, was not a prognostic factor in PCNSL patients for PFS and OS. The small number of patients with sarcopenia in this series may have influenced results.