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OBJECTIVE: Femoroacetabular impingement (FAI) and hip dysplasia (HD) are frequently evaluated by isotropic CT (3DCT) for preoperative planning at the expense of radiation. The aim was to determine if isotropic MRI (3DMR) imaging can provide similar quantitative and qualitative morphological information as 3DCT. METHODS: 25 consecutive patients with a final diagnosis of FAI or HD were retrospectively selected from December 2016-December 2017. Two readers (R1, R2) performed quantitative angular measurements on 3DCT and 3DMR, blinded to the diagnosis and each other's measurements. 3DMR and 3DCT of the hips were qualitatively and independently evaluated by a radiologist (R3), surgeon (R4), and fellow (R5). Interobserver and intermodality comparisons were performed. RESULTS: The ICC was good to excellent for all measurements between R1 and R2 (ICC:0.60-0.98) and the majority of intermodality measurements for R1 and R2. Average inter-reader and inter-modality PABAK showed good to excellent agreement for qualitative reads. On CT, all alpha angles (AA) were significantly lower in dysplasia patients than in cam patients (p < 0.05). All lateral center-edge angle (LCEA) were significantly lower in dysplasia than in cam patients (p < 0.05). On MR, AA at 12, 1, and 2 o'clock, and LCEA at center were significantly lower in dysplasia patients than in cam patients (p < 0.05). CONCLUSION: 3DMR offers similar qualitative and quantitative analysis as 3DCT in adult painful hip conditions. ADVANCES IN KNOWLEDGE: 3DMR has good potential to replace 3DCT and serve as a one-stop modality for bone and soft tissue characterizations in the pre-operative evaluation of FAI and HD.

To evaluate the relationships between acromial anatomy and developmental alterations with rotator cuff tears in female patients and compare these parameters on radiographs and corresponding MRIs along with inter-reader performance. Patient demographics, symptoms, and acromial characteristics on radiograph (acromial index, lateral acromion angle, subacromial space on AP and Y- views, acromial anterior and lateral downsloping) and MRI (shape, slope, spur, osteoarthrosis, os acromiale) were recorded. Radiographic and MRI findings were compared and correlated with rotator cuff pathology on MRI. Inter-reader analysis was performed. A total of 140 MRIs from 137 female patients were included. No significant correlation (p > 0.05) existed between acromial parameters and rotator cuff tears, except for a smaller subacromial space on the Y view and spurs correlated with subscapularis tendon tear (p = 0.02, p = 0.04). The presence of lateral downsloping on MRI correlated with a smaller lateral acromion angle (p = 0.0002) and the presence of lateral downsloping on radiography (p = 0.0015). Inter-reader agreements were good to excellent (ICC: 0.65–0.89). Subacromial impingement anatomy characteristics have no significant associations with supraspinatus or infraspinatus tears in symptomatic women. Among different measures, supine MRI can be reliably used to identify lateral downsloping of the acromion.

To investigate the reliability of multicompartmental volumetric mesenchymal segmentations on MRI and their correlations with anthropomorphic and clinical parameters.A consecutive series of middle-age (35-50 year old) female volunteers with variable body mass index (BMI) and MRI scans performed as a part of the Dallas Heart Study were included. A semi-automatic segmentation tool was used to partition different mesenchymal tissues- fat, muscle, and bone on MRI of pelvis. Total volumes of each compartment were calculated and compared between overweight/obese (BMI = 25 kg/mThere were statistically significant positive correlations between fat volume and BMI (p 0.0001), muscle volume and height (p = 0.03), and bone volume and height (p 0.0001). Significant inverse correlations were found between bone volume and BMI (p = 0.002). Fair to good interobserver reliability was seen with muscle and fat volumes (ICC = 0.43-0.64) and excellent reliability was seen with bone volumes (ICC = 0.78-0.79). Statistically significant inverse correlations were found between MVPA and age (p = 0.01), and TT with BMI and weight (p = 0.01, 0.03).Multi-compartment mesenchymal tissue volume quantification on pelvic MRI is reliable in females. Inverse correlation of bone volume with BMI has potential implications for future risk of fracture.

Aim To assess inter-reader reliability of metatarsus adductus (MA) using the traditional method and Engel's angle (EA) on radiography and magnetic resonance imaging (MRI) and assess correlations with hallux valgus (HV). Methods and materials Ninety consecutive patients with radiographs and MRI of the foot were included. Two readers measured HV angle (HVA), traditional metatarsus adductus angle (MAA), and EA on radiographs and HVA and EA on MRI. Three- and two-way mixed model analyses were used for reader agreements. Ninety-five percent bootstrap confidence intervals were calculated. The linear mixed model was used for association between HVA and EA/MAA. Results Mean age and male to female ratio was 54.2±15.4 and 0.4:1, respectively. Mean HVA and EA were 20.6±9.4 and 21.2±8, 21.2±8.3 and 22.4±7.5 on radiographs and MRI, respectively. Mean MAA was 18.5±5.7 on radiographs. Inter-reader agreement was good for EA (ICC=0.73, 0.6) and moderate for MAA (ICC=0.41). Positive correlations between HVA, MAA, and EA on radiographs and MRI were found, but none were statistically significant (p=0.44 and 0.87). Conclusion Engel's angle is more reproducible. Although positive correlations exist between the degrees of HV and MA, they are not statistically significant.

The two most widely used measurements for diagnosing and assessing the severity of hallux valgus are the hallux valgus angle (HVA) and the intermetatarsal angle (IMA). Traditionally, these have been measured by using the midaxial lines approximating the axis of each bone. A new simpler point method has been recently suggested for measuring these angles by connecting points along the medial corners of each bone. Interreader reliability of these measurements on X-ray and MRI as well as intermethod and intermodality differences have not been assessed. A series of 56 consecutive patients between 18 and 100 years old with no history of foot trauma or orthopedic hardware in their feet were included. All had AP and lateral X-rays and MRI performed on the same foot between April 27, 2015 and March 9, 2016. Two readers measured HVA and IMA using both the traditional midaxial and new point methods. ICC correlations were obtained. The interreader reliability for HVA was similar on point method (0.92) and traditional method (0.94). For the IMA, the ICC was 0.77 on point method versus 0.76 on traditional method. The intermodality agreement (between X-ray and MRI) was higher for HVA (ICC = 0.85, 0.88) as compared to IMA (0.58, 0.74), respectively on both methods. The mean difference between the methods was larger on traditional method = 5.5 for HVA and 2.5° for IMA. HVA is more reliable than IMA on both methods and modalities and a significant difference exists between the magnitudes of values obtained using the two methods. Level of Clinical Evidence: 3

Malreduction of distal tibiofibular syndesmosis (DTFS) leads to poor functional outcomes after ankle fracture surgery. Difficulty achieving anatomic alignment of the syndesmosis is due to variable morphology of the fibular incisura of the tibia and a paucity of literature regarding its morphologic characteristics. We surveyed 775 consecutive ankle computed tomography (CT) scans performed from June 2008 to December 2011, and 203 (26.2%) were included for evaluation. Two observers performed quantitative measurements and qualitative evaluated fibular incisura morphology. Tang ratios for fibular rotation, anterior and posterior tibiofibular distances, fibular incisura depth, and subjective morphologies on CT were assessed using conventional multiplanar reconstruction (MPR) and maximum intensity projections (MIPs). On conventional CT, the mean Tang ratio was 0.97 ± 0.06; the mean anterior tibiofibular distance was 2.17 ± 0.87 mm; the mean posterior tibiofibular distance was 3.52 ± 0.94 mm; and the mean depth of fibular incisura was 3.29 ± 1.19 mm. Five morphologic variations of the fibular incisura were identified: crescentic, trapezoid, flat, chevron, and widow's peak. The most common fibular incisura morphology was crescentic (61.3%), followed by trapezoid shape (25.1%); the least common morphology was flat (3.1%). Interobserver variability with intraclass correlation coefficient (ICC) was slightly higher for all quantitative measures on MPR (ICC = 0.72 to .81) versus MIP (ICC = 0.64 to 0.75). ICC for incisura shape and depth assessments was poor on both modalities (0.13 to 0.38). This comprehensive CT study reports on quantitative and qualitative descriptive measures to evaluate fibular incisura morphologies and fibular orientation. It also defines the frequency of DTFS measures and the interobserver performance on 2 CT evaluation methods.

The menisci play an important role in knee kinematics. Their unique anatomy allows them to channel forces generated during knee movements through the larger tibio-femoral condylar surfaces while simultaneously resisting deleterious hoop stresses. Although physiologic meniscal extrusion occurs with every knee joint movement, pathologic meniscal extrusion subjects the knee to persistent and excessive load transmission. This renders the knee structures susceptible to injury or exacerbates worsening of existing knee joint internal derangement. Detection and quantification of meniscus extrusion is important given its association with underlying pathological processes and internal derangements such as cartilage loss, osteoarthritis and meniscal tears. The medial and lateral menisci vary in size, attachments and load transmission, and the medial meniscus is more susceptible to injury. In this article, the authors illustrate the role of meniscus kinematics, and the identification and quantification of medial meniscal extrusion. Multimodality imaging appearances and implications of presence of medial meniscal extrusion in different knee joint pathologies are discussed with review of the relevant literature.

Background Cross-sectional imaging is not currently used in planning Total Hip Arthroplasty (THA). The aim of our study is to determine correlations between CT parameters and outcomes following THA. Methods A prospective registry of patients who underwent total joint arthroplasty was reviewed for patients who: (1) underwent THA, (2) had a CT between 1 year before and 6 months after surgery, and (3) completed perioperative WOMAC and Harris Hip Score (HHS) questionnaires. Two readers measured CT parameters, yielding mean Hounsfield Units, area, average diameter, and perimeter of the psoas major, gluteus medius and minimus muscles. A segmentation algorithm determined visceral and subcutaneous fat area, and waist circumference. ICC was calculated for each measurement to examine inter-reader agreement. Regression analyses were performed to select measurements with most impact on outcome scores. Results Twenty-eight patients met inclusion criteria (17 female, 11 male), having mean (+/− standard deviation) age of 54.4 +/− 14.8 years and BMI 29.0 +/− 6.3 kg/m2. Correlations were found between HHS and age (0.650, p = 0.018), height (−1.263, p = 0.009), visceral-to-subcutaneous fat area ratio at the psoas level (0.511, p = 0.018), and waist circumference at the psoas level (1.759, p = 0.002). Inter-reader analysis showed ICC > 0.850 for all measurements. Conclusion Age and height, as well as CT-derived visceral-to-subcutaneous fat area ratio and waist circumference significantly correlate with postsurgical HHS scores following THA. Our study suggests that parameters derived from cross-sectional CT imaging can be useful additional preoperative planning tool for THA.

Peripheral nerve sheath tumors (PNSTs) are neoplasms derived from neoplastic Schwann cells or their precursors. Whereas benign PNSTs are relatively common and considered curable lesions, their malignant counterparts are rare but highly aggressive and require early diagnosis and treatment. MR imaging has been the modality of choice for noninvasive evaluation of PNSTs. This article discusses the features of PNSTs in conventional and advanced MR imaging, and it emphasizes the features that help differentiate benign and malignant variants.

The lumbosacral (LS) plexus is a complicated network of nerves, and the complex anatomy is resolvable using high-resolution three-dimensional (3D) magnetic resonance neurography. This article focuses on 3D imaging evaluation of the anatomy and the pathology of various LS plexus branch nerves.

MR neurography (MRN) techniques continue to evolve, leading to a better demonstration of peripheral nerve anatomy and pathology. This article discusses various technical perspectives and provides recommendations to obtain the best possible high-resolution imaging of the peripheral nerves in various areas of the body. We also discuss technical perspectives of whole-body MRN and its potential utility.

Polyneuropathies can be classified as either primarily demyelinating or axonal, and further as hereditary or acquired. It is important to recognize acquired neuropathies because some are amenable to treatment. Clinical findings and electrophysiology are used in the routine diagnosis of these conditions. Magnetic resonance neurography (MRN) is a helpful supplementary diagnostic tool. This article discusses the typical clinical findings, electrophysiology findings, and MRN appearances of common hereditary or acquired neuropathies such as chronic inflammatory demyelinating neuropathy, multifocal motor neuropathy, diabetic neuropathy, chemotherapy-induced neuropathy, and postsurgical neuropathy.

OBJECTIVE. In this article, we will review the normal anatomy and imaging features of various neuromuscular abnormalities related to suprascapular neuropathy. CONCLUSION. Suprascapular neuropathy can be difficult to distinguish from rotator cuff pathology, plexopathy, and radiculopathy. Electrodiagnostic studies are considered the reference standard for diagnosis; however, high-resolution 3-T MR neurography (MRN) can play an important role. MRN enables direct visualization of the nerve and simultaneous assessment of the cervical spine, brachial plexus, and rotator cuff.

The 3D short tau inversion recovery (STIR) sequence is routinely used in clinical MRI to achieve robust fat suppression. However, the performance of the commonly used adiabatic inversion pulse, hyperbolic secant (HS), is compromised in challenging areas with increased BTo demonstrate the frequency offset corrected inversion (FOCI) pulse as an efficient fat suppression STIR pulse with increased robustness to BProspective.Initial evaluation was performed in phantoms and one healthy volunteer by varying the B3T; 3D TSE-STIR with HS and FOCI pulses.Brachial plexus images were qualitatively evaluated by two musculoskeletal radiologists independently using a four-point grading scale for fat suppression, shading artifacts, and nerve visualization.The Wilcoxon signed-rank test with P 0.05 was considered statistically significant.Simulations and phantom experiments demonstrated broader bandwidth (2.5 kHz vs. 0.83 kHz, increased BThe FOCI pulse has increased robustness to B1 Techinical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;48:1104-1111.

Purpose The clinical neurosensory testing (NST) is currently the reference standard for the diagnosis of traumatic and nontraumatic peripheral trigeminal neuropathies (PTNs), but exhibits both false-positive and false-negative results compared with surgical findings and frequently results in treatment decision delays. We tested the hypothesis that magnetic resonance neurography (MRN) of PTNs can serve as a diagnostic modality by correlating the NST, MRN, and surgical findings. Materials and Methods Sixty patients with traumatic and nontraumatic PTN of varying etiologies and Sunderland classifications underwent NST, followed by MRN using 1.5T and 3.0T scanners. The protocol included 2-dimensional and 3-dimensional (3D) imaging, including diffusion imaging and isotropic 3D PSIF. The MRN findings were read by 2 readers in consensus with the clinical findings but without knowing the side of abnormality. The MRN results were summarized using the Sunderland classification. In 26 patients, surgery was performed, and the Sunderland classification was assigned using the surgical photographs. Agreement between the MRN findings and NST/surgical classification was evaluated using kappa statistics. Pearson's correlation coefficient was used to assess the correlation between continuous measurements of MRN/NST and surgical classification. Results Of the 60 patients, 19 males and 41 females, mean age 41 years (range 12 to 75), with 54 complaints of altered sensation of the lip, chin, or tongue, including 16 with neuropathic pain and 4 with no neurosensory complaint, were included. Third molar surgery (n = 29) represented the most common cause of traumatic PTN. Assuming 1 nerve abnormality per patient, the lower class was accepted, a kappa of 0.57 was observed between the MRN and NST classification. A kappa of 0.5 was found between MRN and surgical findings with a Pearson correlation coefficient of 0.67. Conclusions MRN anatomically maps PTNs and stratifies the nerve injury and neuropathies with moderate to good agreement with NST and surgical findings for clinical use.

This review article reviews muscle function and anatomy, describes normal magnetic resonance (MR) imaging anatomy, and shows a spectrum of abnormal imaging findings. It covers the lumbrical, interosseous, and thenar and hypothenar muscles. The described spectrum of abnormalities includes anatomical variants, exercise-induced MR signal changes, denervation syndromes, and myositis, as well as tumors. Advanced imaging techniques are discussed at the end to provide a look at future hand muscle imaging.

Objective To determine the clinical value of multiparametric whole-body (WBMRI) over whole-spine magnetic resonance imaging (WSMRI) in patients with neurofibromatosis type 1 (NF1). Methods A consecutive series of 30 patients with known NF1 underwent WBMRI screening using anatomic, diffusion, and contrast imaging over a 30-month period. Thirteen of 30 patients also had WSMRI. Tumors were classified per location and morphology and were software segmented to determine numbers and volumes. Extra tumor burden detected by WBMRI was assessed. The comparison was made between WBMRI and WSMRI in 13 patients who had both types of scans. Enhancement characteristics were noted and 2 readers recorded apparent diffusion coefficient (ADC) in 30 patients with WBMRI scans. Interobserver performance was assessed using intraclass correlations. A 2-sample test was used for testing mean differences between tumors. Results The age of 30 patients with WBMRI and 13 patients with WSMRI were 39.4 ± 14.4 and 41.54 ± 10.79 years (mean ± standard deviation) and male/female ratio was 1:1.73 and 1:2.25, respectively. Only 1 patient was found to have a heterogeneously enhancing lumbar paraspinal malignant peripheral nerve sheath tumor, seen on both WBMRI and WSMRI. The additional total number of tumors on WBMRI was 2766 and 2602 tumors were missed on WSMRI. The volume of tumors was 16,053 cm3 and 15,614 cm3 of tumor burden was incrementally detected on WBMRI. Mean ADC of superficial tumors was significantly lower than that of deep tumors (1.93 ± 0.39 × 10−3 mm2/second and 2.26 ± 0.56 × 10−3 mm2/second, respectively; P = 0.009), whereas no ADC differences were seen in plexiform versus discrete tumors (P = 0.64). Interobserver performance for ADC was excellent (intraclass correlation, 0.84). Conclusions Multiparametric WBMRI provides superior determination of tumor burden and should be considered as a preferred method for evaluation of patients with NF1.

Hallux valgus (HV) is a common deformity of the great toe affecting >23% of adults in the United States. The severity of the deformity is traditionally analyzed using radiographs to determine measurements such as the HV and intermetatarsal angles. We sought to determine the relationship between the radiographic and magnetic resonance imaging (MRI) measurements because this is not yet known. Two of us analyzed a series of 56 consecutive patients who had had radiographs and MRI performed on the same foot between April 27, 2015 and March 9, 2016 and who satisfied all other inclusion and exclusion criteria (age 18 to 100 years, no history of recent foot trauma, and no metal hardware in the foot). We found excellent interreader reliability (intraclass correlation 0.89 to 0.96) and intermodality agreement (intraclass correlation 0.83 to 0.91). The HV angle measured 15.0° ± 8.8° on the MRI scans and 13.8° ± 8.7° on the radiographs (mean difference -1.15° ± 3.89°), and the intermetatarsal angle was 9.0° ± 3.1° on the MRI scans and 8.8° ± 2.9° on the radiographs (mean difference -0.22° ± 2.10°). The HV measurements were reliable on both radiographs and MRI for the range of values tested. Small intermodality statistically significant differences in HV angle measurements were found; however, these might not be enough to be clinically significant.

To evaluate inter-reader performance for cross-sectional area and fat quantification of bilateral sciatic nerves on MRI and assess correlations with anthropometrics. In this IRB-approved, HIPPA-compliant study, three readers performed a cross-sectional analysis of 3T lumbosacral plexus MRIs over an 18-month period. Image slices were evaluated at two levels (A and B). The sciatic nerve was outlined using a free hand region of interest tool on PACS. Proton-density fat fraction (FF) and cross-sectional areas were recorded. Inter-reader agreement was assessed using intra-class correlation coefficient (ICC). Spearman correlation coefficients were used for correlations with age, BMI and height and Wilcoxon rank sum test was used to assess gender differences. A total of 67 patients were included in this study with male to female ratio of 1:1. Inter-reader agreement was good to excellent for FF measurements at both levels (ICC=0.71–0.90) and poor for sciatic nerve areas (ICC=0.08–0.27). Positive correlations of sciatic FF and area were seen with age (p value

Magnetic resonance (MR) imaging plays an important role in the evaluation of bacterial and tuberculous spondylodiscitis and associated complications. Owing to its high sensitivity and specificity, it is a powerful diagnostic tool in the early diagnosis of ongoing infections, and thus provides help in prompt initiation of appropriate, therapy which may be medical or surgical, by defining the extent of involvement and detection of complications such as epidural and paraspinal abscesses. More specifically, MR imaging helps in differentiating bacterial from tuberculous infections and enables follow up of progression or resolution after appropriate treatment. However, other non-infectious pathology can demonstrate similar MR imaging appearances and one should be aware of these potential mimickers when interpreting MR images. Radiologists and other clinicians need to be aware of these potential mimics, which include such pathologies as Modic type I degenerative changes, trauma, metastatic disease and amyloidosis. In this pictorial review, we will describe and illustrate imaging findings of bacterial and tuberculous spondylodiscitis, their complications and non-infectious pathologies that mimic these spinal infections.

Melorheostosis is an uncommon, sporadic, sclerosing bone lesion that may affect the adjacent soft tissues. It has been associated with many entities such as osteopoikilosis, soft tissue vascular malformations, bone and soft tissue tumors, nephrotic syndrome, segmental limb contractures, osteosarcoma, desmoid tumor, and mesenteric fibromatosis. Synovial osteochondromatosis is a benign neoplasia of the hyaline cartilage presenting as nodules in the subsynovial tissue of a joint or tendon sheath. The intra-articular extension of melorheostosis mimicking synovial osteochondromatosis has not been reported before. In this article, the authors describe an unusual case mimicking synovial chondromatosis arising as a result of melorheostosis and their characteristic imaging findings.

Bone marrow lesions on magnetic resonance (MR) imaging are common and may be seen with various pathologies. The authors outline a systematic diagnostic approach with proposed categorization of various etiologies of bone marrow lesions. Utilization of typical imaging features on conventional MR imaging techniques and other problem-solving techniques, such as chemical shift imaging and diffusion-weighted imaging (DWI), to achieve accurate final diagnosis has been highlighted.

Superficial soft-tissue masses arising from skin appendages, metastasis, and inflammatory lesions have been widely reported. However, nerve-related superficial mass-like lesions other than peripheral nerve sheath tumors are less commonly described. High resolution magnetic resonance imaging (MRI) is an excellent non-invasive tool for the evaluation of such lesions. In this article, the authors discuss the entire spectrum of these lesions and also outline a systemic diagnostic approach.

The most common sites of nerve entrapment are in the upper extremity, commonly diagnosed based on clinical findings and electrophysiologic studies. Cross-sectional imaging modalities, such as ultrasonography and magnetic resonance (MR) imaging, have been used to enhance diagnostic accuracy and provide anatomic mapping of abnormalities. MR neurography offers multiplanar high-resolution imaging of upper extremity nerves as well as adjacent soft tissues, and provides an objective assessment of the neuromuscular anatomy and related abnormalities. This article reviews the normal 3-T MR neurographic appearance of the upper extremity nerves, and abnormal findings related to injury, entrapment, and other pathologic conditions.

Magnetic resonance neurography (MRN) is a specialized technique that is rapidly becoming part of the diagnostic algorithm of peripheral nerve pathology. However, in order for this modality to be considered appropriate, its value compared with current methods of diagnosis should be established. Therefore, radiologists involved in MRN research should use appropriate methodology to evaluate MRN's effectiveness with a multidisciplinary approach. This article reviews the various tiers of research available to assess the clinical value of a diagnostic modality with an emphasis on how to evaluate the impact of MRN on diagnostic thinking and therapeutic decisions.

Various methods of cross-sectional imaging are used for visualization of the cranial nerves, relying heavily on MR imaging. The success of the MR imaging sequences for visualization of cranial nerves depends on their anatomic context at the point of evaluation. The heterogeneity of opinion regarding optimal evaluation of the cranial nerves is partly a function of the complexity of cranial nerve anatomy. A variety of approaches are advocated and variations in equipment and terminology cloud the field. This article proposes a segmental classification and corresponding nomenclature for imaging evaluation of the cranial nerves and reviews technical considerations and applicable literature.

The magnetic resonance neurography (MRN) examination is rapidly becoming a part of the diagnostic algorithm of patients with peripheral neuropathy; however, because of the technical demands and the lack of required reading skills, the examination is relatively underutilized and is currently limited to a few tertiary care centers. The radiologists with interest in peripheral nerve imaging should be able to perform and interpret this examination to exploit its potential for widespread use. This article outlines the systematic, stepwise approach to its interpretation and a brief discussion of the imaging pitfalls.

Proper performance of magnetic resonance neurography (MRN) is essential not only to make the examination easier to interpret but also for its accurate evaluation. This article outlines the technical considerations of MRN, various imaging pulse sequences available on current scanners, as well as their relative advantages and disadvantages. In addition, a guide to the optimal use of high-resolution and high-contrast MRN technique is provided, which will aid clinicians in attaining a good-quality examination.

Objective This study aimed to investigate whether patellofemoral T2 cartilage changes are associated with lateral patellofemoral friction syndrome (PFS), as indicated by an edema-like signal within the superolateral infrapatellar (Hoffa) fat pad. Methods In this institutional review board-approved retrospective study of 510 consecutive patients, 49 patients with 50 knee magnetic resonance imaging examinations demonstrating normal or low-grade patellofemoral cartilage abnormalities (whole-organ magnetic resonance imaging score [WORMS] score, ≤2) were included. Twenty-two examinations with PFS (cases) were compared with an age- and sex-matched cohort of 28 examinations without PFS (controls). A 3-T magnetic resonance imaging was performed with multi-echo, spin-echo T2 mapping. Two readers measured in consensus malalignment parameters, including patellar height index, tibial tuberosity to trochlear groove distance, and sulcus angle. Bulk T2 cartilage values in the lateral and medial patellofemoral compartment, central weight-bearing medial and lateral femoral condyles were measured independently. Interobserver agreement was quantified using concordance correlation coefficients. Demographics, anatomic measurements, whole-organ magnetic resonance imaging scores, and cartilage T2 values were compared between cases and controls using Fisher exact test, Wilcoxon rank sum test, and mixed-effects models. Results Cases demonstrated higher patellar height index (P = 0.002) and tibial tuberosity to trochlear groove distance (P = 0.02). Interobserver agreement for T2 values was good overall (concordance correlation coefficient range, 0.65-0.93). Cases demonstrated higher medial facet patellar bulk T2 (38.1 [7.5] ms) versus controls (33.6 [7.3] ms) (P = 0.02); otherwise, there were no significant differences in regional T2 values. Conclusions T2 mapping in patients with PFS demonstrates increased cartilage T2 in the medial patellar facet, possibly reflecting collagen alteration from early chondromalacia (softening) or increased water content related to altered contact pressures.

The authors described 2 cases of pisotriquetral instability, which were diagnosed in patients presenting with ulnar wrist clicking and pain. The diagnosis was made first using 4-dimensional computed tomography, which helped further interventions and management in both patients.

Objective: Sesamoid displacement (SD) and rotation are important components in the preoperative assessment of hallux valgus (HV). To date, Inter reader reliability (IRR) of SD on X-rays and MRI, correlations with hallux valgus angle (HVA), and qualitative changes of the hallux-sesamoid complex (HSC) on MRI have not been studied. The aim of this study was to correlate sesamoid malalignment with HV severity and findings of internal joint derangement. Methods: Two readers analyzed a series of 56 consecutive patients who had X-rays and MRI performed on the same foot within 3 months of each other. Multiple measures of SD on X-rays and MRI and the sesamoid rotation angle (SRA) on MRI were assessed and correlated with HVA and various qualitative features at the HSC including cartilage, plantar plate, and collateral ligament abnormalities. Results: We found excellent IRR (ICC = 0.79 – 0.99) for SRA on MR, but poor IRR for lateral sesamoid displacement (LDS) and tibial sesamoid position (TSP) scales on both modalities. Good IRR was also seen for morphologic abnormalities of HSC. The absolute value of the SRA on MR positively correlated with HVA ( p < 0.0001). LDS and TSP on both modalities lacked a significant correlation with HVA ( p > 0.05). No correlation was found between any measure of SD or rotation with HSC morphologic changes ( p > 0.05). Conclusion: Among different measures of sesamoid malalignment, sesamoid rotation angle measured on MRI can be used to judge the severity of HV; however, it does not correlate with qualitative morphologic abnormalities of the HSC. Advances in knowledge: The MRI measurement of SRA is a better indicator of sesamoid displacement relative to the HSC than standard AP radiographic measures of non-rotational sesamoid displacement; however, it should not be used to predict qualitative morphologic abnormalities of the HSC.

Sclerotic (T2 dark) lesions of the spine are infrequent and, as a result, these are often missed or misdiagnosed. Plain films may not be always available during magnetic resonance imaging (MRI) readout. Knowledge of such lesions and their imaging appearances on MRI evaluation is essential for a reader. Additionally, a systematic approach is important to accurately diagnose these lesions. In this article we discuss the various causes of spinal sclerotic lesions, describe their MRI characteristics with relevant case examples, and outline a systematic approach to their evaluation.

The authors report a vascular malformation mimicking a plexiform peripheral nerve sheath tumor. Three Tesla magnetic resonance neurography with high-resolution anatomic and advanced functional diffusion tensor imaging was helpful in evaluating full extent of the lesion and characterizing its internal architecture.

The authors report an unusual case of radial mononeuropathy caused by epithelioid sarcoma and describe the anatomical 3-Tesla MR neurography and the functional diffusion tensor imaging findings of the case, which were subsequently confirmed on surgical excision and histopathology.

To compare lumbar muscle fat-signal fractions derived from three-dimensional dual gradient-echo magnetic resonance (MR) imaging and multiple gradient-echo MR imaging with fractions from single-voxel MR spectroscopy in patients with low back pain.This prospective study had institutional review board approval, and written informed consent was obtained from all study participants. Fifty-six patients (32 women; mean age, 52 years ± 15 [standard deviation]; age range, 20-79 years) with low back pain underwent standard 1.5-T MR imaging, which was supplemented by dual-echo MR imaging, multi-echo MR imaging, and MR spectroscopy to quantify fatty degeneration of bilateral lumbar multifidus muscles in a region of interest at the intervertebral level of L4 through L5. Fat-signal fractions were determined from signal intensities on fat- and water-only images from both imaging data sets (dual-echo and multi-echo fat-signal fractions without T2* correction) or directly obtained, with additional T2* correction, from multi-echo MR imaging. The results were compared with MR spectroscopic fractions. The Student t test and Bland-Altman plots were used to quantify agreement between fat-signal fractions derived from imaging and from spectroscopy.In total, 102 spectroscopic measurements were obtained bilaterally (46 of 56) or unilaterally (10 of 56). Mean spectroscopic fat-signal fraction was 19.6 ± 11.4 (range, 5.4-63.5). Correlation between spectroscopic and all imaging-based fat-signal fractions was statistically significant (R(2) = 0.87-0.92; all P.001). Mean dual-echo fat-signal fractions not corrected for T2* and multi-echo fat-signal fractions corrected for T2* significantly differed from spectroscopic fractions (both P.01), but mean multi-echo fractions not corrected for T2* did not (P = .11). There was a small measurement bias of 0.5% (95% limits of agreement: -6.0%, 7.2%) compared with spectroscopic fractions.Large-volume image-based (dual-echo and multi-echo MR imaging) and spectroscopic fat-signal fractions agree well, thus allowing fast and accurate quantification of muscle fat content in patients with low back pain.

To assess the diagnostic accuracy and observer performance of 3-Tesla magnetic resonance neurography (MRN) in the evaluation of meralgia paresthetica (MP).Two independent readers were blinded to the clinical diagnosis and evaluated the MRN studies of the pelvis of 11 patients with MP and 28 control participants. In each study, the lateral femoral cutaneous nerves were assessed for signal alteration and/or neuroma formation, indicating lateral femoral cutaneous neuropathy, at various levels along their course. Intra- and inter-observer reliability was evaluated.Both readers exhibited substantial intraobserver agreement in detecting signal alterations and neuroma formation of the lateral femoral cutaneous nerve (LFCN). The readers demonstrated moderate interobserver agreement in detecting signal alteration of the LFCN and poor interobserver agreement in diagnosing neuroma formation. Sensitivity, specificity, positive predictive value, and negative predictive value of LFCN neuropathy diagnosis were ≥ 71 % and ≥ 94 % for both readers respectively. The diagnostic test accuracy was ≥ 90 % for both readers.3-Tesla MRN provides reliable and accurate diagnostic evaluation of meralgia paresthetica.

Purpose To develop and evaluate magnetic resonance (MR) neurography of the brachial plexus with robust fat and blood suppression for increased conspicuity of nerves at 3.0 T in clinically feasible acquisition times. Materials and Methods This prospective study was HIPAA compliant, with institutional review board approval and written informed consent. A low-refocusing-flip-angle three-dimensional (3D) turbo spin-echo (TSE) sequence was modified to acquire both in-phase and out-of-phase echoes, required for chemical shift (Dixon) reconstruction, in the same repetition by using partial echoes combined with modified homodyne reconstruction with phase preservation. This multiecho TSE modified Dixon (mDixon) sequence was optimized by using simulations and phantom studies and in three healthy volunteers. The sequence was tested in five healthy volunteers and was evaluated in 10 patients who had been referred for brachial plexopathy at 3.0 T. The images were evaluated against the current standard of care, images acquired with a 3D TSE short inversion time inversion recovery (STIR) sequence, qualitatively by using the Wilcoxon signed-rank test and quantitatively by using the Friedman two-way analysis of variance, with P.05 considered to indicate a statistically significant difference. Results Multiecho TSE-mDixon involving partial-echo and homodyne reconstruction with phase preservation achieved uniform fat suppression in half the imaging time compared with multiacquisition TSE-mDixon. Compared with 3D TSE STIR, fat suppression, venous suppression, and nerve visualization were significantly improved (P.05), while arterial suppression was better but not significantly so (P = .06), with increased apparent signal-to-noise ratio in the dorsal nerve root ganglion and C6 nerve (P.001) with the multiecho TSE-mDixon sequence. Conclusion The multiecho 3D TSE-mDixon sequence provides robust fat and blood suppression, resulting in increased conspicuity of the nerves, in clinically feasible imaging times and can be used for MR neurography of the brachial plexus at 3.0 T.

BACKGROUND AND PURPOSE: The number of centers currently performing 3D fat-suppressed isotropic imaging is limited. If the angular orientations of the major lumbosacral plexus nerves on 3D isotropic MR neurography could be determined, similar planes could be prescribed during acquisition of 2D or 3D nonisotropic techniques for optimal depiction of various nerves. Our aim was to determine oblique sagittal and coronal angular measurements for longitudinal depiction of lumbosacral plexus nerves. Interobserver and intraobserver performance and mean calibers of sciatic and femoral nerves were also determined. MATERIALS AND METHODS: A consecutive series of lumbosacral plexus MR neurography examinations with 3D nerve-selective imaging performed during a 10-month period on a 3T scanner were evaluated. Two observers performed reconstructions and angular measurements. Sciatic and femoral nerve diameters were measured. Descriptive statistics and intraclass correlation coefficient correlations were used. RESULTS: There were 52 subjects, 11 men and 41 women. Mean sagittal thecal sac angles for coronal demonstration of lumbosacral plexus nerve roots from L1 to S1 for 2 independent observers measured 13.58° ± 2.87° and 13.61° ± 2.18°. Mean sagittal femoral nerve angles were 27.78° ± 4.81° and 28.94° ± 4.49°, and mean sagittal sciatic nerve angles were −10.7° ± 3.75° and −11.82° ± 2.87°. Coronal angular measurements of the femoral and sciatic nerves were similar. The intraclass correlation coefficient was moderate (0.582–0.671) for interobserver performance. For intraobserver performance among various angular measurements, the intraclass correlation coefficient was moderate to good (0.586–0.788). Femoral nerve caliber on MR imaging was almost half that of the sciatic nerve. Mean right femoral nerve thickness was 4.52 ± 1.11 mm and 4.85 ± 0.64 mm for the 2 observers, and mean left femoral nerve thickness was 4.48 ± 0.97 mm and 4.94 ± 0.57 mm. Mean right sciatic nerve thickness was 9.71 ± 1.76 mm and 9.94 ± 0.83 mm, and mean left sciatic nerve thickness was 10.03 ± 1.71 mm and 9.98 ± 0.99 mm. CONCLUSIONS: Angular lumbosacral plexus measurements aid in the prescription of different planes on MR imaging for the optimal longitudinal demonstration of nerves.

Chronic pelvic pain is a disabling condition that affects a large number of men and women. It may occur after a known inciting event, or it could be idiopathic. A common cause of pelvic pain syndrome is neuropathy of the pelvic nerves, including the femoral and genitofemoral nerves, ilioinguinal and iliohypogastric nerves, pudendal nerve, obturator nerve, lateral and posterior femoral cutaneous nerves, inferior cluneal nerves, inferior rectal nerve, sciatic nerve, superior gluteal nerve, and the spinal nerve roots. Pelvic neuropathy may result from entrapment, trauma, inflammation, or compression or may be iatrogenic, secondary to surgical procedures. Imaging-guided nerve blocks can be used for diagnostic and therapeutic management of pelvic neuropathies. Ultrasonography (US)-guided injections are useful for superficial locations; however, there can be limitations with US, such as its operator dependence, the required skill, and the difficulty in depicting various superficial and deep pelvic nerves. Magnetic resonance (MR) imaging-guided injections are radiation free and lead to easy depiction of the nerve because of the superior soft-tissue contrast; although the expense, the required skill, and the limited availability of MR imaging are major hindrances to its widespread use for this purpose. Computed tomography (CT)-guided injections are becoming popular because of the wide availability of CT scanners, the lower cost, and the shorter amount of time required to perform these injections. This article outlines the technique of perineural injection of major pelvic nerves, illustrates the different target sites with representative case examples, and discusses the pitfalls. (©)RSNA, 2016.

To evaluate magnetization-prepared 3D TA clinical MR-HIFU system (3T) was used to generate thermal lesions (n = 24) in the skeletal muscles of three pigs. TLesion dimensions on TAfter MR-HIFU exposures, measurements of the acute thermal damage patterns in muscle using a magnetization-prepared 3D T1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:354-364.

Flexor tendon rupture is an unusual complication following collagenase injection to relieve contractures. These patients require a close follow-up and in the event of tendon rupture, a decision has to be made whether to repair the tendon or manage the complication conservatively. The authors report the utility of MRI in the prognostication and management of a patient with Dupuytren’s contracture, who underwent collagenase injection and subsequently developed flexor digitorum profundus tendon rupture.

OBJECTIVES: The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration Whole-Body MRI (WB-MRI) Working Group reviewed the existing literature on WB-MRI, an emerging technology for assessing disease in patients with neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN), to recommend optimal image acquisition and analysis methods to enable WB-MRI as an endpoint in NF clinical trials.METHODS: A systematic process was used to review all published data about WB-MRI in NF syndromes to assess diagnostic accuracy, feasibility and reproducibility, and data about specific techniques for assessment of tumor burden, characterization of neoplasms, and response to therapy.RESULTS: WB-MRI at 1.5T or 3.0T is feasible for image acquisition. Short tau inversion recovery (STIR) sequence is used in all investigations to date, suggesting consensus about the utility of this sequence for detection of WB tumor burden in people with NF. There are insufficient data to support a consensus statement about the optimal imaging planes (axial vs coronal) or 2D vs 3D approaches. Functional imaging, although used in some NF studies, has not been systematically applied or evaluated. There are no comparative studies between regional vs WB-MRI or evaluations of WB-MRI reproducibility.CONCLUSIONS: WB-MRI is feasible for identifying tumors using both 1.5T and 3.0T systems. The STIR sequence is a core sequence. Additional investigation is needed to define the optimal approach for volumetric analysis, the reproducibility of WB-MRI in NF, and the diagnostic performance of WB-MRI vs regional MRI.

Mentoring is an essential part of a resident's career development. It plays an important role in nurturing, and sustaining success along the career path of a young physician. Mentoring is a long-term goal that is development-driven rather than performance-driven. Although specific learning goals may be used as a basis, the focus of mentoring may also include self-confidence, self-perception, and work-life balance. A number of residency programs have implemented mentoring programs in their institutions. This article discusses the importance of mentoring, illustrates "do's and don'ts" for mentees and demonstrates how to choose the ideal mentor. Finally, a "mentoring quiz" is designed to evaluate your mentoring relationship.

Three dimensional (3D) printing can be used to create material models to aid preoperative planning of complex orthopedic procedures as exemplified by this case of total hip arthroplasty failure due to infection with resulting severe acetabular bone stock deficiency. The 3D model allowed for trialing of the acetabular component to determine cup size, position, and screw placement. Most importantly, the model confirmed that there was not a pelvic discontinuity and the revision shell would be sufficient for the reconstruction. Previously, the cost and complexity of utilization of 3D printers were prohibitive. Recent improvements in commercially available 3D printers have made rapid prototype model creation a realistic option, which can facilitate difficult surgery.

Magnetic resonance imaging (MRI) is a noninvasive modality of choice for the detection of static peroneal tendon pathologic features. The depiction of peroneal tendon subluxation using real-time kinematic MRI has not been previously reported. We describe the MRI and intraoperative correlation of peroneal tendon and retinacular pathologic findings, and the novel use of kinematic MRI in the illustration of peroneal tendon subluxation.

The care of patients with musculoskeletal malignancies has increasingly become a multidisciplinary function. Radiologists play an important role in many areas of these patients' care including initial diagnosis, staging, in many cases guiding therapy, and monitoring treatment response. However, the gold standard for the final diagnosis of these diseases remains the histopathologic proof. Intense efforts have been made to develop non-invasive methods of determining the tumor grade, or a surrogate, in order to predict biologic behavior, aid early treatment decisions, and provide prognostic information. Multiple imaging modalities have been employed in this domain-including computed tomography (CT); anatomic magnetic resonance (MR) imaging techniques; functional MR imaging sequences such as dynamic contrast enhancement (DCE), diffusion weighted imaging (DWI), MR spectroscopy (MRS); and positron emission tomography (PET). This article reviews current available literature in this realm and highlights future directions towards the potential of non-invasive imaging in grading of soft tissue sarcomas.