Improved Resolution and Image Quality of Musculoskeletal Magnetic Resonance Imaging using Deep Learning-based Denoising Reconstruction: A Prospective Clinical Study.

OBJECTIVE: To prospectively evaluate a deep learning-based denoising reconstruction (DLR) for improved resolution and image quality in musculoskeletal (MSK) magnetic resonance imaging (MRI). METHODS: Images from 137 contrast-weighted sequences in 40 MSK patients were evaluated. Each sequence was performed twice, first with the routine parameters and reconstructed with a routine reconstruction filter (REF), then with higher resolution and reconstructed with DLR, and with three conventional reconstruction filters (NL2, GA43, GA53). The five reconstructions (REF, DLR, NL2, GA43, and GA53) were de-identified, randomized, and blindly reviewed by three MSK radiologists using eight scoring criteria and a forced ranking. Quantitative SNR, CNR, and structure's full width at half maximum (FWHM) for resolution assessment were measured and compared. To account for repeated measures, Generalized Estimating Equations (GEE) with Bonferroni adjustment was used to compare the reader's scores, SNR, CNR, and FWHM between DLR vs. NL2, GA43, GA53, and REF. RESULTS: Compared to the routine REF images, the resolution was improved by 47.61% with DLR from 0.39 ± 0.15 mm2 to 0.20 ± 0.06 mm2 (p < 0.001). Per-sequence average scan time was shortened by 7.93% with DLR from 165.58 ± 21.86 s to 152.45 ± 25.65 s (p < 0.001). Based on the average scores, DLR images were rated significantly higher in all image quality criteria and the forced ranking (p < 0.001). CONCLUSION: This prospective clinical evaluation demonstrated that DLR allows approximately two times finer resolution and improved image quality compared to the standard-of-care images.

Association between headache and suicidality: An analysis of universal suicide screening data at a large urban county hospital.

BACKGROUND: Identifying individuals at increased risk of suicide is important, particularly those who present for treatment for nonpsychiatric chief complaints who may go undetected. It has been found that pain symptoms, such as headache, are associated with suicide, although this association requires further characterization. This study examined specific components of suicidality in relation to headache subtypes. METHODS: This study retrospectively reviewed 2,832,835 nonpsychiatric adult clinical encounters at a large county hospital, where a standardized suicide risk screening tool, the Columbia-Suicide Severity Rating Scale (C-SSRS), was universally implemented. The C-SSRS assesses specific components of suicidality: wish to be dead and suicidal ideation, method, intent, plan, and action. Multivariate logistic regressions were performed to assess the association between headache, as well as headache subtype (migraine, tension, or cluster), and each component of suicidality. RESULTS: There were significant positive associations between presenting with a headache and 2 specific components of suicidality: wish to be dead and suicidal action. Individuals with tension headache may have a lower risk of wishing to be dead compared to those with migraine and cluster headaches. CONCLUSIONS: The association of headaches with specific elements of sui-cidality demonstrates the potential yield of identification of suicide risk among individuals with nonpsychiatric presentations.

Two-year outcomes with a bioinductive collagen implant used in augmentation of arthroscopic repair of full-thickness rotator cuff tears: final results of a prospective multicenter study.

BACKGROUND: Full-thickness rotator cuff tears (FTRCTs) represent a common shoulder injury that, if untreated, can progress in size, become increasingly painful, and inhibit function. These lesions are often surgically repaired, with double-row arthroscopic repair often preferred for larger tears. Biological augmentation technologies have been developed to improve rates of postoperative radiographic retear and enhance patient-reported outcomes after surgical FTRCT repair. This study sought to confirm that augmented repair with a bioinductive bovine collagen implant results in favorable retear rates and patient outcomes with follow-up to 2 years. METHODS: A prospective multicenter cohort study was undertaken to determine the efficacy and safety of augmenting single- or double-row arthroscopic repair of FTRCTs with a bioinductive bovine collagen implant. Of 115 adult patients participating, 66 (57.4%) had medium (1-3-cm) tears and 49 (42.6%) had large (3-5-cm) tears. Magnetic resonance imaging and patient-reported outcomes (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES] and Constant-Murley Score [CMS]) were performed and recorded at baseline, 3 months, 1 year, and 2 years. RESULTS: Mean duration of follow-up was 2.1 years (range, 1.5-2.9 years). Between baseline and 2-year follow-up, mean total thickness of the supraspinatus tendon increased by 12.5% for medium tears and by 17.1% for large tears. Radiographic retear was noted in 7 of 61 available patients (11.5%) with medium tears, and in 14 of 40 patients (35.0%) with large tears. In both groups, these tears primarily occurred before the 3-month follow-up visit (13 of 21 [61.9%]). Radiographic retear with the supplemented double-row (DR) repair technique was 13.2% overall (12 of 91 DR patients; 11.3% for medium tears and 15.8% for large tears). The minimal clinically important difference was achieved by >90% of patients with both medium and large tears for both ASES and CMS. There were 2 serious adverse events classified by the treating surgeon as being possibly related to the device and/or procedure (1 case of swelling/drainage and 1 case of intermittent pain). Nine patients (7.8%; 4 medium tears and 5 large tears) required reoperation of the index rotator cuff surgery. CONCLUSION: Final 2-year data from this study confirm that using this implant in augmentation of arthroscopic double-row repair of FTRCTs provides favorable rates of radiographic retear and substantial functional recovery. The relative safety of the device is also further supported.

Genes Associated with Calcium Signaling are Involved in Alcohol-Induced Breast Cancer Growth.

BACKGROUND: Alcohol consumption is a risk factor for breast cancer, contributing to up to nearly 23,000 new cases each year. Mechanistic studies show that alcohol increases tumor aggressiveness and metastatic potential, promotes angiogenesis, induces chronic inflammation, and dysregulates RNA polymerase III-related genes. Alcohol has also been shown to affect estrogen signaling in breast cancer, including in our study of the transcriptomic effects of alcohol in breast cancer cells. METHODS: To elucidate mechanisms of action of alcohol in breast cancer, we carried out secondary analyses of our alcohol-responsive transcriptome data using gene ontology and pathway databases and analysis tools and cistromic data analysis of candidate transcription factors which may mediate the transcriptomic alterations. Predicted alcohol-responsive pathways and mechanisms were perturbed and examined experimentally in breast cancer cells. The clinical relevance of identified genes was determined by expression profiles in patient samples and correlation with disease outcomes and alcohol consumption in previously published study cohorts. RESULTS: Gene ontology analysis showed that alcohol alters the expression of many metabolism-related genes, and cistromic data of differentially expressed genes revealed the potential involvement of nuclear factor of activated T cells 3 (NFATC3) in mediating the transcriptomic effects of alcohol. Pathway analysis also predicted regulation of calcium signaling by alcohol in breast cancer cells. Chemical perturbation of this pathway reversed the effect of alcohol on breast cancer cell growth and reduced the elevated cytosolic Ca2+ levels induced by alcohol. Expression levels of alcohol-responsive genes in tumor samples from breast cancer patients are associated with poor disease outcomes. Moreover, expression of some of these genes was altered in breast cancer patients who consumed alcohol previously as compared to those who did not drink. CONCLUSION: Alcohol alters expression of genes that regulate intracellular calcium levels and downstream signaling pathways which drive breast cancer cell proliferation and disease progression.

Isolated bioinductive repair of partial-thickness rotator cuff tears using a resorbable bovine collagen implant: two-year radiologic and clinical outcomes from a prospective multicenter study.

BACKGROUND: Current surgical treatment options for partial-thickness tears (eg, takedown and repair, in situ repair) are limited by the degenerative nature of the underlying tendon and may require extensive intervention that can alter the anatomic footprint. The complexity of available techniques to address these issues led to the development of a resorbable collagen implant, which can be used to create a bioinductive repair of partial-thickness tears. METHODS: We prospectively enrolled 33 patients with chronic, degenerative, intermediate-grade (n = 12), or high-grade (n = 21) partial-thickness tears (11 articular, 10 bursal, 4 intrasubstance, and 8 hybrid) of the supraspinatus tendon in a multicenter study. After arthroscopic subacromial decompression without a traditional rotator cuff repair, a bioinductive implant was secured over the bursal surface of the tendon. Clinical outcomes were assessed using American Shoulder and Elbow Surgeons (ASES) and Constant-Murley scores (CMS) preoperatively and at 3 months, 1 year, and 2 years postoperatively. Magnetic resonance imaging was performed to assess postoperative tendon healing and thickness at the original tear site. RESULTS: At 2-year follow-up, mean ASES and CMS scores improved both clinically and statistically at 1 and 2 years, compared with baseline, for intermediate- and high-grade tears. There was magnetic resonance imaging evidence of new tissue fill-in within the original baseline tear in 100% of the intermediate-grade tears and 95% of the high-grade tears. In 90.9% of the intermediate-grade tears and 84.2% of the high-grade tears, this new tissue fill-in represented at least an additional 50% of the volume of the initial lesion. From baseline to 2-year follow-up, the mean tendon thickness increased by 1.2 mm (standard deviation, 1.3; P = .012) and 1.8 mm (standard deviation, 2.2; P = .003) in the intermediate- and high-grade tears, respectively. The analysis of tear grade and location revealed no statistically significant difference in the change in mean tendon thickness at any time point. One patient with a high-grade articular lesion demonstrated progression to a full-thickness tear; however, the patient was noncompliant and the injury occurred while shoveling snow 1 month after surgery. Neither tear location nor treatment of bicep pathology affected the ASES or CMS scores at any follow-up point. No serious adverse events related to the implant were reported. CONCLUSION: Final results from this 2-year prospective study indicate that the use of this resorbable bovine collagen implant for isolated bioinductive repair of intermediate- and high-grade partial-thickness rotator cuff tears of the supraspinatus is safe and effective, regardless of tear grade and location.

Novel Liver X Receptor Ligand GAC0001E5 Disrupts Glutamine Metabolism and Induces Oxidative Stress in Pancreatic Cancer Cells.

Pancreatic ductal adenocarcinoma (PDAC) is the predominant form of pancreatic cancer with a high mortality rate due to the lack of early detection and effective treatment options for advanced diseases. Metabolic reprogramming, a common hallmark of malignant transformation in pancreatic cancer, is critical for the growth and survival of cancer cells and a potential target mechanism for the treatment of pancreatic cancer. PDAC cells have upregulated glutamine metabolism to meet their biosynthetic and oxidative demands. Liver X receptors (LXRs) are ligand-dependent transcription factors involved in maintaining metabolic homeostasis. LXRs regulate critical cancer-related processes and pathways, including cholesterol, glucose and lipid metabolism, and inflammatory and immune responses. Analysis of transcriptomic data from PDAC clinical samples reveals overexpression of LXRs and their target genes in tumors as compared to normal tissue controls. Targeting LXRs with the novel LXR inverse agonist and degrader GAC0001E5 inhibited PDAC cell proliferation. Using a metabolomics approach, we discovered that 1E5 inhibits glutamine anaplerosis and induces oxidative stress, which are detrimental to PDAC cells. These findings highlight a novel role for LXR in regulating cancer metabolism and the potential application of LXR modulators in targeting cancer metabolism in pancreatic cancer and other malignancies.

Quantitative mapping of glenohumeral cartilage in asymptomatic subjects using 3 T magnetic resonance imaging.

OBJECTIVE: The purpose of this study was to develop quantitative T2 mapping methodology in asymptomatic shoulders for the entire mappable region of the glenohumeral cartilage in the coronal and sagittal planes, to assess the feasibility and limitations of the development of a diagnostic tool for future application in symptomatic patients. MATERIALS AND METHODS: Twenty-one asymptomatic volunteers underwent sagittal and coronal glenohumeral T2 mapping, as the spherical geometry of the humeral head obviates the need to evaluate the entire glenohumeral cartilage in a single plane. The humeral head cartilage orthogonal to the mapping plane was manually segmented in the sagittal and coronal planes, whereas the glenoid cartilage was segmented in the coronal plane. Cartilage T2 summary statistics were calculated and coverage in each mapping plane was qualitatively assessed. RESULTS: The mean ± standard deviation of the glenoid cartilage T2 was 38 ± 2 ms. The coronal and sagittal mapping planes captured different regions of the humeral head with some overlap: inferior-medial to superior-lateral versus superior/superior-lateral to anterior-lateral and posterior-lateral respectively. The mean humeral head cartilage T2 in the coronal plane was 41 ± 3 ms, which was significantly different (p < 0.05) from the sagittal plane mean of 34 ± 2 ms. CONCLUSION: This study measured characteristic glenoid and humeral head cartilage T2 values over the area mappable with two planes. Importantly, this study demonstrated that two-dimensional mapping in a single plane or two combined planes cannot capture the entirety of the semi-spherical humeral head cartilage. This highlights the need for three-dimensional T2 mapping techniques in the shoulder.

Radiologic and clinical evaluation of a bioabsorbable collagen implant to treat partial-thickness tears: a prospective multicenter study.

BACKGROUND: Treatment of partial-thickness cuff tears remains controversial. Although conservative therapy may treat symptoms, these defects do not spontaneously heal and conversion to a full-thickness lesion with subsequent repair may alter the tendon footprint. The ability to induce new tissue formation and limit tear progression in intermediate- and high-grade partial-thickness tears without surgical repair may represent a significant advancement in the treatment paradigm for these lesions. METHODS: We prospectively enrolled 33 patients with chronic, degenerative, intermediate-grade (n = 12) or high-grade (n = 21) partial-thickness tears (11 articular, 10 bursal, 4 intrasubstance, and 8 hybrid) of the supraspinatus tendon in a multicenter study. Following arthroscopic subacromial decompression without repair, a bioinductive implant was attached over the bursal surface of the tendon. Clinical outcomes were assessed using American Shoulder and Elbow Surgeons and Constant-Murley scores preoperatively and at 3 and 12 months postoperatively. Magnetic resonance imaging was performed to assess postoperative tendon healing and thickness at the original tear site. RESULTS: At 1-year follow-up, clinical scores improved significantly (P <.0001) and the mean tendon thickness increased by 2.0 mm (P <.0001). Magnetic resonance imaging evidence of complete healing was found in 8 patients and a considerable reduction in defect size was shown in 23, whereas 1 lesion remained stable. In 1 noncompliant patient with a high-grade articular lesion, progression to a full-thickness tear occurred while shoveling snow 1 month after surgery. No serious adverse events related to the implant were reported. CONCLUSIONS: Arthroscopic implantation of a bioinductive collagen scaffold is a safe and effective treatment for intermediate- to high-grade partial-thickness rotator cuff tears of the supraspinatus tendon.

Factors Influencing Postoperative Complications in Reconstructive Microsurgery for Head and Neck Cancer.

PURPOSE: The present study aimed to analyze multiple variables and to determine the factors influencing postoperative complications in reconstructive microsurgeries for head and neck cancer. MATERIALS AND METHODS: This was a retrospective review of the medical records of patients with head and neck cancer who underwent free flap reconstruction after ablation surgery at the Cathay General Hospital (Taipei, Taiwan) from January 2010 to December 2014. Clinical and surgical procedure-related factors were retrieved from a database and analyzed. Major complications included flap failure and life-threatening events. Minor complications were defined as requiring only routine wound care or conservative treatments. To evaluate group differences, the χ2 test was applied for categorical variables and the Mann-Whitney U test was used for continuous variables. RESULTS: In total, 158 patients (145 men [91.8%], 13 women [8.2%]) were included in this study. The mean age of the study population was 52.4 years (range, 34 to 84 yr). The mean body mass index (BMI) was 23.71 kg/m2. Most patients (93.7%) had a history of cigarette smoking. Some patients had diabetes (20.3%) and hypertension (31.6%). The percentage of patients who underwent radiotherapy before surgery was 19.6%. The percentage whose flap required a salvage operation was 8.9%. The success rate of the microvascular surgeries was 95.6%. The major complication rate was 6.3% and the minor complication rate was 27.8%. No surgical mortality was noted. CONCLUSION: In these patients, poor nutrition status, indicated by low BMI and low albumin level, was associated with a greater tendency to develop postoperative complications. Patients who had diabetes or who had received radiotherapy before surgery had a high risk for major complications. A large skin paddle seemed to be an influencing factor for minor complications, such as wound dehiscence and superficial loss of flaps.

Predictors of outcomes after arthroscopic transosseous equivalent rotator cuff repair in 155 cases: a propensity score weighted analysis of knotted and knotless self-reinforcing repair techniques at a minimum of 2 years.

PURPOSE: To evaluate the outcomes of two commonly used transosseous-equivalent (TOE) arthroscopic rotator cuff repair (RCR) techniques for full-thickness supraspinatus tendon tears (FTST) using a robust multi-predictor model. METHODS: 155 shoulders in 151 patients (109 men, 42 women; mean age 59 ± 10 years) who underwent arthroscopic RCR of FTST, using either a knotted suture bridging (KSB) or a knotless tape bridging (KTB) TOE technique were included. ASES and SF-12 PCS scores assessed at a minimum of 2 years postoperatively were modeled using propensity score weighting in a multiple linear regression model. Patients able to return to the study center underwent a follow-up MRI for evaluation of rotator cuff integrity. RESULTS: The outcome data were available for 137 shoulders (88%; n = 35/41 KSB; n = 102/114 KTB). Seven patients (5.1%) that underwent revision rotator cuff surgery were considered failures. The median postoperative ASES score of the remaining 130 shoulders was 98 at a mean follow-up of 2.9 years (range 2.0-5.4 years). A higher preoperative baseline outcome score and a longer follow-up had a positive effect, whereas a previous RCR and workers' compensation claims (WCC) had a negative effect on final ASES or SF 12 PCS scores. The repair technique, age, gender and the number of anchors used for the RCR had no significant influence. Fifty-two patients returned for a follow-up MRI at a mean of 4.4 years postoperatively. Patients with a KSB RCR were significantly more likely to have an MRI-diagnosed full-thickness rotator cuff re-tear (p < 0.05). CONCLUSIONS: Excellent outcomes can be achieved at a minimum of 2 years following arthroscopic KSB or KTB TOE RCR of FTST. The preoperative baseline outcome score, a prior RCR, WCC and the length of follow-up significantly influenced the outcome scores. The repair technique did not affect the final functional outcomes, but patients with KTB TOE RCR were less likely to have a full-thickness rotator cuff re-tear. LEVEL OF EVIDENCE: Level III, Retrospective Comparative Study.

Correction to: Predictors of outcomes after arthroscopic transosseous equivalent rotator cuff repair in 155 cases: a propensity score weighted analysis of knotted and knotless self-reinforcing repair techniques at a minimum of 2 years.

The author claims that his name is wrongly listed on PubMed. It seems, that first and last name have been mixed up. Correct first name is: J. Christoph (on PubMed: J.).

No degeneration found in focal cartilage defects evaluated with dGEMRIC at 12-year follow-up.

Background and purpose - The natural history of focal cartilage defects (FCDs) is still unresolved, as is the long-term cartilage quality after cartilage surgery. It has been suggested that delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a biomarker of early OA. We aimed to quantitatively evaluate the articular cartilage in knees with FCDs, 12 years after arthroscopic diagnosis. Patients and methods - We included 21 patients from a cohort of patients with knee pain who underwent arthroscopy in 1999. Patients with a full-thickness cartilage defect, stable knees, and at least 50% of both their menisci intact at baseline were eligible. 10 patients had cartilage repair performed at baseline (microfracture or autologous chondrocyte implantation), whereas 11 patients had either no additional surgery or simple debridement performed. Mean follow-up time was 12 (10-13) years. The morphology and biochemical features were evaluated with dGEMRIC and T2 mapping. Standing radiographs for Kellgren and Lawrence (K&L) classification of osteoarthritis (OA) were obtained. Knee function was assessed with VAS, Tegner, Lysholm, and KOOS. Results - The dGEMRIC showed varying results but, overall, no increased degeneration of the injured knees. Degenerative changes (K&L above 0) were, however, evident in 13 of the 21 knees. Interpretation - The natural history of untreated FCDs shows large dGEMRIC variations, as does the knee articular cartilage of surgically treated patients. In this study, radiographic OA changes did not correlate with cartilage quality, as assessed with dGEMRIC.

Automated analysis of hip joint cartilage combining MR T2 and three-dimensional fast-spin-echo images.

PURPOSE: To validate a fully automated scheme to extract biochemical information from the hip joint cartilages using MR T2 mapping images incorporating segmentation of co-registered three-dimensional Fast-Spin-Echo (3D-SPACE) images. METHODS: Manual analyses of unilateral hip (3 Tesla) MR images of 24 asymptomatic volunteers were used to validate a 3D deformable model method for automated cartilage segmentation of SPACE scans, partitioning of the individual femoral and acetabular cartilage plates into clinically defined sub-regions and propagating these results to T2 maps to calculate region-wise T2 value statistics. Analyses were completed on a desktop computer (∼ 10 min per case). RESULTS: The mean voxel overlap between automated A and manual M segmentations of the cartilage volumes in the (clinically based) SPACE images was 73% (100 × 2|A∩M|/[|A|+|M|]). The automated and manual analyses demonstrated a relative difference error <10% in the median "T2 average signal" for each cartilage plate. The automated and manual analyses showed consistent patterns between significant differences in T2 data across the hip cartilage sub-regions. CONCLUSION: The good agreement between the manual and automatic analyses of T2 values indicates the use of structural 3D-SPACE MR images with the proposed method provides a promising approach for automated quantitative T2 assessment of hip joint cartilages.

Prospective In Vivo Comparison of Damaged and Healthy-Appearing Articular Cartilage Specimens in Patients With Femoroacetabular Impingement: Comparison of T2 Mapping, Histologic Endpoints, and Arthroscopic Grading.

PURPOSE: To describe T2 mapping values in arthroscopically determined International Cartilage Repair Society (ICRS) grades in damaged and healthy-appearing articular cartilage waste specimens from arthroscopic femoroacetabular impingement (FAI) treatment. Furthermore, we sought to compare ICRS grades of the specimens with biochemical, immunohistochemistry and histologic endpoints and assess correlations with T2 mapping. METHODS: Twenty-four patients were prospectively enrolled, consecutively, between December 2011 and August 2012. Patients were included if they were aged 18 years or older and met criteria that followed the clinical indications for arthroscopy to treat FAI. Patients with prior hip trauma including fracture or dislocation or who have undergone prior hip surgery were excluded. All patients received a preoperative sagittal T2 mapping scan of the hip joint. Cartilage was graded intraoperatively using the ICRS grading system, and graded specimens were collected as cartilage waste for histologic, biochemical, and immunohistochemistry analysis. RESULTS: Forty-four cartilage specimens (22 healthy-appearing, 22 damaged) were analyzed. Median T2 values were significantly higher among damaged specimens (55.7 ± 14.9 ms) than healthy-appearing specimens (49.3 ± 12.3 ms; P = .043), which was most exaggerated among mild (grade 1 or 2) defects where the damaged specimens (58.1 ± 16.4 ms) were significantly higher than their paired healthy-appearing specimens (48.7 ± 15.4 ms; P = .026). Severely damaged specimens (grade 3 or 4) had significantly lower cumulative H&E than their paired healthy-appearing counterparts (P = .02) but was not statistically significant among damaged specimens with mild (grade 1 or 2) defects (P = .198). Among healthy-appearing specimens, median T2 and the percentage of collagen fibers oriented parallel were significantly correlated (rho = 0.425, P = .048). CONCLUSIONS: This study outlines the potential for T2 mapping to identify early cartilage degeneration in patients undergoing arthroscopy to treat FAI. Findings in ICRS grade 1 and 2 degeneration corresponded to an increase in T2 values. Further biochemical evaluation revealed a significant difference between healthy-appearing cartilage and late degeneration in cumulative H&E as well as significantly lower percentage of collagen fibers oriented parallel and a higher percentage of collagen fibers oriented randomly when considering all grades of cartilage damage. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Predictive Value of 3-T Magnetic Resonance Imaging in Diagnosing Grade 3 and 4 Chondral Lesions in the Hip.

PURPOSE: To assess the diagnostic capability and predictive value of 3-T magnetic resonance imaging (MRI) in detecting grade 3 and 4 cartilage lesions in the hip. METHODS: From August 2010 to April 2015, patients who underwent 3-T MRI and hip arthroscopy were included in the study. Data were prospectively collected and retrospectively reviewed. A radiologist prospectively documented MRI findings, and the surgeon documented cartilage damage at arthroscopy using the Outerbridge grading system. Arthroscopy was considered the diagnostic gold standard. This study was approved by the institutional review board. RESULTS: The study group comprised 606 patients, with 354 men (58%) and 252 women (42%). The mean patient age was 34 years (range, 18 to 71 years). For femoral head defects, the sensitivity was 61% (95% confidence interval [CI], 53% to 68%), specificity was 58% (95% CI, 55% to 62%), positive predictive value was 29% (95% CI, 25% to 33%), and negative predictive value was 84% (95% CI, 81% to 87%). For chondral defects of the acetabulum, the sensitivity was 80% (95% CI, 75% to 84%), specificity was 41% (95% CI, 38% to 44%), positive predictive value was 42% (95% CI, 39% to 45%), and negative predictive value was 79% (95% CI, 74% to 84%). CONCLUSIONS: The results of this study showed that 3-T MRI had sensitivity, as well as specificity, for identifying chondral defects that is similar to what has been previously reported. MRI showed increased sensitivity when identifying acetabular defects compared with femoral head defects. With a low positive predictive value, MRI may be most useful in ruling out cartilage lesions. LEVEL OF EVIDENCE: Level III, diagnostic study.

The critical shoulder angle is associated with rotator cuff tears and shoulder osteoarthritis and is better assessed with radiographs over MRI.

PURPOSE: The purpose of this study was to determine whether there is an association between the critical shoulder angle (CSA) and rotator cuff tears (RCT) as well as osteoarthritis (OA), and to compare the reproducibility and accuracy of CSA values as measured with radiograph and MRI. METHODS: Based on a pre hoc power analysis, three independent reviewers measured CSAs for three groups of 10 age-matched patients each (RCT group, OA group, and non-RCT/non-OA group) using radiographs and MRIs. Inter- and intra-observer agreements of CSAs were determined with intraclass correlation coefficients. ANOVA analysis was performed. RESULTS: Interobserver and intra-observer agreements on radiographs were 0.87 (95 % CI 0.78-0.93) and 0.91 (95 % CI 0.82-0.96), respectively. Significant differences in mean CSAs by radiographs were found between the groups (RCT 37.3° ± 2.6°; OA 28.7° ± 2.2°; non-RCT/non-OA 32.7° ± 2.5°; p < 0.001). CSAs obtained from MRI scans had interobserver agreement of 0.62 (95 % CI 0.43-0.78) and intra-observer agreement of 0.68 (95 % CI 0.50-0.80). There was a significant correlation between the patients' pathologies and CSAs measured by radiographs (r = 0.44; p = 0.02) and MRI (r = 0.50; p = 0.01). A significant difference in mean CSAs measured on radiograph versus MRI was seen in the OA group (28.7° ± 2.2° vs. 31.3° ± 4.4°; p = 0.01). CONCLUSION: CSA measurements obtained from radiographs demonstrated excellent interobserver agreement with less variability than CSAs from MRI, especially in OA patients. This study confirms an association between the CSA and RCTs as well as OA pathology. Assessing the CSA may be helpful during diagnostic evaluation of patients with shoulder pain and can help predict pathology. LEVEL OF EVIDENCE: Retrospective cohort study, Level IV.

Quantitative MRI characterization of arthroscopically verified supraspinatus pathology: comparison of tendon tears, tendinosis and asymptomatic supraspinatus tendons with T2 mapping.

PURPOSE: Quantitative MRI T2 mapping is a non-invasive imaging technique sensitive to biochemical changes, but no studies have evaluated T2 mapping in pathologic rotator cuff tendons. It was sought to evaluate the efficacy of T2 mapping in detecting differences in the supraspinatus tendon (SST) among patients with tendinosis, partial tears and minimally retracted full-thickness tears, relative to asymptomatic volunteers. METHODS: The pathologic cohort consisted of two arthroscopically verified groups: tendinosis and a tear group of partial tears or minimally retracted full-thickness tears, and was compared to an asymptomatic cohort with no prior history of shoulder pathology. The SST was manually segmented from the footprint to the medial humeral head in the coronal and sagittal planes and divided into six clinically relevant subregions. Mean T2 values and inter- and intra-rater reliability were assessed. RESULTS: In the anterolateral subregion, the tear group exhibited significantly higher mean T2 values (43.9 ± 12.7 ms) than the tendinosis (34.9 ± 3.9 ms; p = 0.006) and asymptomatic (33.6 ± 5.3 ms; p = 0.015) groups. In the posterolateral subregion, the tear group had higher mean T2 values (45.2 ± 13.7) than the asymptomatic group (34.7 ± 6.7; p = 0.012). Inter- and intra-rater reliability was mostly excellent (ICC > 0.75). CONCLUSION: T2 mapping is an accurate non-invasive method to identify quantitatively early rotator cuff pathology. The lateral region in the coronal plane in particular may differentiate partial and small minimally retracted full-thickness tears from tendinosis and asymptomatic tendons. Understanding and being able to measure quantitatively the process of tendon degeneration and subsequent tearing may help clinicians to better predict at-risk groups and to stratify treatment options. LEVEL OF EVIDENCE: III.

Magnetic resonance imaging characterization of individual ankle syndesmosis structures in asymptomatic and surgically treated cohorts.

PURPOSE: Historically, syndesmosis injuries have been underdiagnosed. The purpose of this study was to characterize the 3.0-T MRI presentations of the distal tibiofibular syndesmosis and its individual structures in both asymptomatic and injured cohorts. METHODS: Ten age-matched asymptomatic volunteers were imaged to characterize the asymptomatic syndesmotic anatomy. A series of 21 consecutive patients with a pre-operative 3.0-T ankle MRI and subsequent arthroscopic evaluation for suspected syndesmotic injury were reviewed and analysed. Prospectively collected pre-operative MRI findings were correlated with arthroscopy to assess diagnostic accuracy [sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)]. RESULTS: Pathology diagnosed on pre-operative MRI correlated strongly with arthroscopic findings. Syndesmotic ligament disruption was prospectively diagnosed on MRI with excellent sensitivity, specificity, PPV, NPV, and accuracy: anterior inferior tibiofibular ligament (87.5, 100, 100, 71.4, 90.5 %); posterior inferior tibiofibular ligament (N/A, 95.2, 0.0, 100, 95.2 %); and interosseous tibiofibular ligament (66.7, 86.7, 66.7, 86.7, 81.0 %). CONCLUSIONS: Pre-operative 3.0-T MRI demonstrated excellent accuracy in the diagnosis of syndesmotic ligament tears and allowed for the visualization of relevant individual syndesmosis structures. Using a standard clinical ankle MRI protocol at 3.0-T, associated ligament injuries could be readily identified. Clinical implementation of optimal high-field MRI sequences in a standard clinical ankle MRI exam can aid in the diagnosis of syndesmotic injuries, augment pre-operative planning, and facilitate anatomic repair by providing additional details regarding the integrity of individual syndesmotic structures not discernible through physical examination and radiographic assessments. LEVEL OF EVIDENCE: II.

Automatic detection of anatomical landmarks on the knee joint using MRI data.

PURPOSE: To propose a new automated learning-based scheme for locating anatomical landmarks on the knee joint using three-dimensional (3D) MR image data. MATERIALS AND METHODS: This method makes use of interest points as candidates for landmarks. All candidates are evaluated by a "coarse to fine" 3D feature descriptor computed from manually placed landmarks in training datasets. The results are refined using a multi-classifier boosting system. We demonstrate our method by the detection of 24 landmarks on the knee joint of 35 subjects. To verify the robustness, the test datasets differ in contrast, resolution, patient positioning, and health condition of the knee joint. The proposed method is evaluated by measuring the distance between manually placed landmarks and automatically detected landmarks and the computational cost for detecting one landmark in a 3D dataset. RESULTS: The results reveal that the method is capable of localizing landmarks with a reasonable accuracy (1.64 ± 1.03 mm [mean ± standard deviation]), sensitivity (97%) and run time efficiency (4.82 s). CONCLUSION: This study suggests that the proposed method is an accurate and robust approach for the automated landmark detection in various MR datasets. The proposed method can be used as the initialization or constraint in higher level medical image processing workflows such as in kinematic description, segmentation and registration.

Automatic model-based semantic registration of multimodal MRI knee data.

PURPOSE: To propose a robust and automated model-based semantic registration for the multimodal alignment of the knee bone and cartilage from three-dimensional (3D) MR image data. MATERIALS AND METHODS: The movement of the knee joint can be semantically interpreted as a combination of movements of each bone. A semantic registration of the knee joint was implemented by separately reconstructing the rigid movements of the three bones. The proposed method was validated by registering 3D morphological MR datasets of 25 subjects into the corresponding T2 map datasets, and was compared with rigid and elastic methods using two criteria: the spatial overlap of the manually segmented cartilage and the distance between the same landmarks in the reference and target datasets. RESULTS: The mean Dice Similarity Coefficient (DSC) of the overlapped cartilage segmentation was increased to 0.68 ± 0.1 (mean ± SD) and the landmark distance was reduced to 1.3 ± 0.3 mm after the proposed registration method. Both metrics were statistically superior to using rigid (DSC: 0.59 ± 0.12; landmark distance: 2.1 ± 0.4 mm) and elastic (DSC: 0.64 ± 0.11; landmark distance: 1.5 ± 0.5 mm) registrations. CONCLUSION: The proposed method is an efficient and robust approach for the automated registration between morphological knee datasets and T2 MRI relaxation maps.