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An understanding of the common MRI findings observed after decompression surgery is important. However, to date, no study addressing this has been published. The aim of this study was to analyze and describe the immediate postoperative MRI findings after lumbar decompression surgery. We retrospectively analyzed the immediate postoperative MRIs of 121 consecutive patients who underwent lumbar decompression surgery between July 2017 and June 2018. Changes in stenosis at the decompressed and adjacent levels, epidural fat edema, epidural and subdural fluid collections, nerve root swelling, facet joint effusions, intervertebral disc signal, and paravertebral muscle edema were correlated with clinical characteristics. Both groups had reduced central canal stenosis postoperatively (p 0.001) but worsened stenosis at adjacent segments. Fluid collection, hemorrhagic or non-hemorrhagic, at the laminectomy site was the commonest finding (one-level: 73.8%, two-level: 88.5%), with a higher percentage of severe central canal compromise in the two-level decompression group (p = 0.003). Other postoperative MRI findings, such as epidural fat edema, nerve root swelling, subdural fluid collection, and facet joint effusion, were noted without statistical significance. In conclusion, even with successful decompression for lumbar canal stenosis, increased central canal stenosis at adjacent segments is common on immediate postoperative MRI scans, showing no statistically significant correlation with the immediate postoperative outcome. Postoperative fluid collection at the laminectomy site is the commonest imaging finding, and higher rates of hemorrhagic fluid and more severe central canal compromise occur in two-level decompression, but rarely cause clinical problems.

Background/Aims: Sacroiliitis is a frequent extraintestinal manifestation of in flammatory bowel diseases (IBDs). This study aimed to assess the prevalence of sacroiliitis using a validated screening tool based on abdominopelvic computed tomography (APCT) in Korean patients with Crohn’s disease (CD) and examine potential associations between clinical characteristics and sacroiliitis. Methods: One hundred five patients with CD undergoing APCT for any indica tion at an IBD clinic were matched 1:1 for age and sex with 105 controls without underlying chronic illnesses. Using a validated APCT screening tool that defines sacroiliitis as either ankylosis or a total erosion score (TES) ≥ 3, all computed to mography scans were assessed by two independent, blinded radiologists. We com pared the prevalence of sacroiliitis between CD patients and controls and clinical characteristics between CD patients with and without sacroiliitis. Results: The prevalence of sacroiliitis was significantly higher in CD patients than in controls (13.3% vs. 4.8%, p = 0.030). All subjects with sacroiliitis had a TES ≥ 3, but no ankylosis. The assessment of sacroiliitis in APCT showed excellent in terreader reliability (Cohen’s kappa = 0.933 for presence of sacroiliitis). Sacroiliitis in CD patients was bilateral and asymptomatic. There were no significant associ ations between sacroiliitis and any demographic data or clinical characteristics in these patients. Conclusions: The prevalence of APCT-detected sacroiliitis in CD patients was higher than that in controls, but the condition was asymptomatic. The clinical significance of asymptomatic sacroiliitis in Korean CD patients remains unclear.

We evaluated magnetic resonance imaging (MRI) findings in patients with clinically diagnosed medial epicondylitis (ME) and determined whether any of the MRI findings correlated with the follow-up pain level after nonoperative treatment. We retrospectively reviewed 83 patients who had undergone elbow MRI examinations for clinically diagnosed ME and who were followed-up for more than 6 months. Five categories of MRI findings were selected for qualitative grading: common flexor tendon (CFT) origin signal changes, ulnar collateral ligament (UCL) insufficiency, ulnar neuritis, bony changes of the medial epicondyle, and calcification. The mean follow-up after MRI examination was 21 months. We performed multivariate regression analysis to analyze whether any of these MRI findings were associated with the follow-up pain level after nonoperative treatment. Positive MRI findings included CFT origin signal changes (66%), ulnar neuritis (40%), UCL insufficiency (30%), calcification (27%), and bony changes (18%). Multivariate analysis indicated that CFT origin signal changes were independently associated with the follow-up pain level (β = 3.387; p = 0.004). In patients with clinically diagnosed ME, MRI demonstrated diverse abnormal findings in the CFT origin, ulnar collateral ligament, ulnar nerve, and bone. Among the findings, the severity CFT origin signal changes, which indicates the severity of tendon degeneration in ME, was associated with the follow-up pain level. This information can be helpful in consulting on the prognosis of nonoperative treatment in patients with clinically diagnosed ME.

Background: Malposition of the femoral stem is a risk factor for dislocation after total hip arthroplasty (THA). Currently, two radiological methods are available for the measurement of stem anteversion. However, one method is not applicable in patients with a stiff hip, and the other one cannot differentiate the anteversion and retroversion of the stem. Therefore, we developed a method to measure the stem anteversion and assessed its reliability as well as validity. Methods: Trans-lateral decubitus view of the proximal femur was taken with the patient in lateral decubitus position, the hip in extension and the knee in 90° flexion. Hip anteroposterior (AP) view, trans-lateral decubitus view and CT scan of the hip were taken in 36 patients, who underwent THA. Their mean age was 59.8 (27–84) years and the mean body mass index was 25.2 (18.8–30.9) kg/m2. The stem neck-femoral shaft angle was measured on hip AP view and the trans-lateral decubitus view. Then, the stem anteversion was calculated using the Ogata-Goldsand formula. We assessed the intra- and inter-observer reliabilities and evaluated the validity by comparing with the measurements on CT scan. Results: The intra- and inter-observer reliabilities were 0.934 and 0.935, respectively. The calculated stem anteversion (23.72°±8.17°) correlated well with the stem anteversion on CT scan (23.91°±10.25°), especially when the radiological anteversion was

Hibernoma is a rare benign tumor that arises from vestiges of brown fat. Spinal intraosseous hibernoma has only recently been described in the literature, and only 12 cases have been reported to date due to its extreme rarity. Here, we report the case of a patient who was incidentally diagnosed with an intraosseous hibernoma in the thoracic spine, following a diverse imaging work-up and pathologic confirmation. We correlate the clinical presentation and imaging features of our case with those of previously reported cases during our review of the literature.

Deep gluteal syndrome is an increasingly recognized disease entity, caused by compression of the sciatic or pudendal nerve due to non-discogenic pelvic lesions. It includes the piriformis syndrome, the gemelli-obturator internus syndrome, the ischiofemoral impingement syndrome, and the proximal hamstring syndrome. The concept of the deep gluteal syndrome extends our understanding of posterior hip pain due to nerve entrapment beyond the traditional model of the piriformis syndrome. Nevertheless, there has been terminological confusion and the deep gluteal syndrome has often been undiagnosed or mistaken for other conditions. Careful history-taking, a physical examination including provocation tests, an electrodiagnostic study, and imaging are necessary for an accurate diagnosis. After excluding spinal lesions, MRI scans of the pelvis are helpful in diagnosing deep gluteal syndrome and identifying pathological conditions entrapping the nerves. It can be conservatively treated with multidisciplinary treatment including rest, the avoidance of provoking activities, medication, injections, and physiotherapy. Endoscopic or open surgical decompression is recommended in patients with persistent or recurrent symptoms after conservative treatment or in those who may have masses compressing the sciatic nerve. Many physicians remain unfamiliar with this syndrome and there is a lack of relevant literature. This comprehensive review aims to provide the latest information about the epidemiology, aetiology, pathology, clinical features, diagnosis, and treatment. Cite this article: Bone Joint J 2020;102-B(5):556–567.

Objective To evaluate the effectiveness and long-term outcome predictors of percutaneous sacroplasty (PSP). Methods This single-center study assessed 40 patients with sacral insufficiency fractures using the short-axis technique under C-arm flat-panel detector computed tomography (CT). Two radiologists reviewed the patients' magnetic resonance and CT images to obtain imaging findings before PSP and determine technical success, respectively. The short-term outcomes were visual analog scale score changes and opioid usage reductions. Long-term outcomes were determined using telephone interviews and the North American Spine Society (NASS) patient-satisfaction index at least one year after PSP. Results Technical success was achieved without any significant complications in 39 patients (97.5%). Telephone interviews were possible with 12 patients and failed in 10 patients; death was confirmed in 18 patients. Fifteen patients (50%) re-visited the hospital and received conservative treatment, including spinal injections. Nine patients reported positive satisfaction (NASS patient-satisfaction index 1 or 2), while the negative satisfaction group (NASS patient-satisfaction index 3 or 4, n=3) showed a higher incidence of compression fractures at the thoracolumbar spine level (66.7% vs. 22.2%) and previous spinal injection history (66.7% vs. 33.3%). The poor response group also showed higher incidences of facet joint arthrosis (100% vs. 55.6%), central canal stenosis (100% vs. 22.2%), neural foraminal stenosis (33.3% vs. 22.2%), scoliosis (100% vs. 33.3%), and sagittal malalignment (100% vs. 44.4%). Conclusion PSP was effective for sacral insufficiency fractures and showed good long-term outcomes. Combined compression fractures in the thoracolumbar spine and degenerative lumbar pathologies could be possible poor outcome predictors.

To determine the association of meniscal flounce with the pattern and location of the meniscal tear, concomitant ligamentous injury, amount of knee joint effusion, and flexion and rotation angles. A total of 283 knees of 280 patients were retrospectively reviewed over a 9-month period. Thirty-one magnetic resonance images of patients with meniscal flounce were compared with those of age- and sex-matched control group (n = 62) without meniscal flounce. The presence of meniscal tear was evaluated and, if present, its location and pattern were recorded. The amount of joint effusion was graded, and the joint angle was measured. The Fisher’s exact, Cochran-Armitage trend, and t tests were performed to compare the findings between the two groups. The decision tree analysis was employed to determine the most significant factor of meniscal flounce. Meniscal flounce was present in 11.0% (31/283) of the adult population. Approximately 80.6% of meniscal flounce occurred in the torn medial menisci. The presence of meniscal flounce was significantly associated with tears at the body (p = 0.007), posterior horn (p = 0.001), and meniscocapsular junction (p = 0.002) of the medial meniscus. The decision tree analysis revealed that the posterior horn tear of the medial meniscus was the most significant predictor of meniscal flounce. The most significant factor associated with meniscal flounce is tear at the posterior horn of the medial meniscus, followed by tear at the meniscocapsular junction.

To analyze the incidence and characteristics of intra-articular facet joint injection (FJI)–related adverse events requiring hospitalization and emergency room visits. From January 2007 to December 2017, a total of 11,980 FJI procedures in 6066 patients (mean age 66.8 years, range 15–97 years, M:F = 2004:4062) were performed in our department. Of these, we retrospectively reviewed 489 cases in 432 patients who were hospitalized or visited the emergency room within a month of FJI. FJI-related adverse events were classified as procedure-related complications, drug-related systemic events, or uncertain etiology events, on the basis of consensus of two spine radiologists. This is a descriptive study without statistical analysis. There were 101 FJI-related adverse event cases in 99 patients (mean age 71.8 years, range 39–97 years, M:F = 39:60). The overall incidence of FJI-related adverse events was 0.84% (101/11,980) per case and 1.63% (99/6066) per patient. The incidence of procedure-related complications and drug-related systemic adverse events was 0.07% (8/11,980) and 0.15% (18/11,980), respectively; the rate of uncertain etiology events was 0.63% (75/11,980). All eight procedure-related complication cases involved major complications. There are seven cases of infectious spondylitis and one was progression of systemic aspergillosis to the spine. One patient died of an uncontrolled infection with infective endocarditis, and two patients experienced partial recovery with neurological sequelae. The overall incidence of FJI-related adverse events is low, and procedure-related major complications are rare without dural puncture or epidural hematoma. Nevertheless, infection can occur, resulting in serious outcomes. • The incidence of FJI-related adverse events requiring hospitalization or ER visit was 0.84%. • The incidence of major procedure-related complications was 0.07%. • All major complications were associated with infection and there were no cases of epidural hematoma.

Sagittal parameters of the spine are closely related to the evaluation and treatment of spine disease. However, there has been little research on variations in preoperative sagittal spinal alignment. This study was conducted to assess the variation in sagittal spinal alignment on serial antero-posterior and latero-lateral projections (EOS imaging) in adult patients before spine surgery. The sagittal parameters of 66 patients were collected from two serial images. Comparison between the first and second sagittal parameters was evaluated using the Wilcoxon signed-rank test. Subgroup analysis was performed based on the time interval between radiographs, patient’s age, and type of surgery. The sagittal vertical axis (SVA) exhibited statistically significant changes (p = 0.023), with the mean SVA increasing statistically (61.7 mm vs. 73.6 mm) and standard deviation increasing (51.5 mm vs. 61.6 mm) in the second image. Subgroup analysis showed significant differences in SVA (p = 0.034) in patients with an interval of &gt, 3 months, statistical differences in borderline levels in the SVA (p = 0.049) were observed in patients aged &gt, 65 years. Other parameters did not show statistically significant differences, except for SVA. Furthermore, SVA differences were statistically significant with increases in the EOS interval (&gt, 3 months) and patient age (&gt, 65 years).

OBJECTIVE. The objective of our study was to compare the sensitivity of a deep learning (DL) algorithm with the assessments by radiologists in diagnosing osteonecrosis of the femoral head (ONFH) using digital radiography. MATERIALS AND METHODS. We performed a two-center, retrospective, noninferiority study of consecutive patients (≥ 16 years old) with a diagnosis of ONFH based on MR images. We investigated the following four datasets of unilaterally cropped hip anteroposterior radiographs: training (n = 1346), internal validation (n = 148), temporal external test (n = 148), and geographic external test (n = 250). Diagnostic performance was measured for a DL algorithm, a less experienced radiologist, and an experienced radiologist. Noninferiority analyses for sensitivity were performed for the DL algorithm and both radiologists. Subgroup analysis for precollapse and postcollapse ONFH was done. RESULTS. Overall, 1892 hips (1037 diseased and 855 normal) were included. Sensitivity and specificity for the temporal external test set were 84.8% and 91.3% for the DL algorithm, 77.6% and 100.0% for the less experienced radiologist, and 82.4% and 100.0% for the experienced radiologist. Sensitivity and specificity for the geographic external test set were 75.2% and 97.2% for the DL algorithm, 77.6% and 75.0% for the less experienced radiologist, and 78.0% and 86.1% for the experienced radiologist. The sensitivity of the DL algorithm was noninferior to that of the assessments by both radiologists. The DL algorithm was more sensitive for precollapse ONFH than the assessment by the less experienced radiologist in the temporal external test set (75.9% vs 57.4%; 95% CI of the difference, 4.5-32.8%). CONCLUSION. The sensitivity of the DL algorithm for diagnosing ONFH using digital radiography was noninferior to that of both less experienced and experienced radiologist assessments.

To analyze the causes of pain, imaging characteristics, and therapeutic effect of spinal injection in patients with extreme low back pain or sciatica. We analyzed 381 consecutive patients with extreme low back pain or sciatica visiting our spinal intervention center between January and December 2017. Clinical and imaging characteristics were analyzed. The treatment response, defined as a numerical pain rating scale decrease of ≥ 30%, was measured. Fisher’s exact test was performed to identify the association between the injection response and subsequent lumbar surgery rate. The most frequent cause of pain was spinal stenosis, followed by herniated intervertebral disc, facet osteoarthritis, and osteoporotic compression fracture. A herniated intervertebral disc was the most common disorder in patients

Objective To determine the usefulness of adding contrast-enhanced (CE) magnetic resonance imaging (MRI) to conventional MRI for evaluation of spinal metastases. Materials and methods One-hundred-and-two whole spine MR examinations, obtained for metastasis work-up within a 2-month period, from 65 men and 37 women (mean age, 64 years) with extra-spinal tumor, who also underwent CE-MRI, were retrospectively evaluated by three radiologists. The number of spine segments with bone marrow involvement was interpreted using a 3-point confidence scale (probable metastasis, equivocal, probably benign) during session 1 (conventional imaging) and session 2 (addition of CE-MRI to conventional imaging). The patients were assigned to 14 categories based on the changes in confidence rating between sessions 1 and 2; these were aggregated to four groups indicating the degree of usefulness of CE-MRI: definitely useful, equivocal, not useful, and presumed non-metastatic groups. Clinical information, metastatic bone type, the number of probably metastatic segments, and anatomical level and position were compared among the former three groups. Results The readers assigned 39–53% of cases to the definitely useful group. The number of probably metastatic segments differed significantly among the three groups for all readers (p ≤ 0.046). Age, sex, primary cancer, metastatic bone type, and anatomical level and position were similar. Conclusion Adding CE-MRI to conventional MRI was useful for objectively detecting and characterizing spinal segments with metastases in 39–53% of cases. However, there were no clinical or radiological factors that could predict the usefulness of CE-MRI in evaluating spinal metastases, except for the number of metastatic segments.

To develop and validate a scoring system integrating MRI and laboratory findings to differentiate necrotizing fasciitis (NF) from non-necrotizing fasciitis (non-NF). This retrospective study included 144 subjects who underwent surgery in one of three tertiary referral centers for NF or cellulitis with non-NF. The development cohort consisted of 96 subjects (NF = 47; non-NF = 49) from one center, and the validation cohort consisted of 48 subjects (NF = 23; cellulitis with non-NF = 25) from two different centers. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system and five MRI findings (thickening of the intermuscular deep fascia ≥ 3 mm, extensive involvement of the deep fascia, multi-compartmental involvement in one extremity, presence of gas, and contrast-enhancement pattern) were included in univariate and multivariate logistic regression analysis to identify independent predictors of NF. An additive scoring system was developed using the coefficients of the final regression model. Model performance was assessed for discrimination and calibration. The scoring system was externally validated. The final scoring system consisted of three variables: thickening of the deep fascia ≥ 3 mm, multi-compartmental involvement, and LRINEC score. The new predictive model showed improved performance (area under the receiver operating characteristic curve [AUC], 0.862; positive and negative predictive values, 82% and 79%, respectively), compared with the LRINEC score alone (0.814, 77% and 67%, respectively). The model also showed good discrimination with the external validation dataset (AUC, 0.933). Differentiation of NF from severe cellulitis with non-NF can be achieved with the new predictive scoring system. • The new predictive scoring system integrating two MRI findings with the LRINEC score can help in the differentiation of necrotizing fasciitis from severe cellulitis with non-necrotizing fasciitis. • Thickening of the deep fascia ≥ 3 mm and multi-compartmental involvement were the most important MRI findings for the differentiation.

Ultrasound diathermy is widely used for the treatment of musculoskeletal disorders and other soft tissue injuries. Its use as a therapeutic modality is believed to be safe, with very few reported complications. Here, we report two patients who developed focal bone marrow abnormalities after receiving ultrasound diathermy. Both patients’ magnetic resonance (MR) evaluations revealed linear subchondral bone lesions of the superolateral humeral head similar to those in osteonecrosis. The patients’ symptoms subsequently improved, and available follow-up MR evaluation revealed near complete resolution of bone lesions. These findings suggest that ultrasound diathermy, and its interaction with bone tissue through thermal mechanisms, can cause focal bone marrow abnormalities. Furthermore, the bone marrow abnormalities seem to be transient, resolving upon cessation of ultrasound diathermy, therefore osteonecrosis should be differentiated from this temporal lesion.

The objective of our study was to evaluate the association between anterior tibial translation and injuries on the posterior horn medial meniscus (PHMM) and the integrity of the brake stop mechanism of the PHMM in the anterior cruciate ligament (ACL)-deficient knee.This retrospective study included 85 consecutive patients with an arthroscopically confirmed complete ACL tear. Anterior tibial translation was quantitatively measured using sagittal MRI at the midpoint of the lateral femoral condyle. The "uncovered medial meniscus" sign was considered positive if a vertical line tangent to the posteriormost margin of the medial tibial plateau intersected the PHMM at the midpoint of the medial femoral condyle on sagittal MRI. Concomitant injuries on the structures of the posteromedial and posterolateral corners of the knee, including PHMM tear and meniscal ramp lesion, were recorded. Stratified subgroup analysis and multivariable regression analysis were performed to identify factors associated with anterior tibial translation.The uncovered medial meniscus sign was positive in 21.2% (18/85) of patients and was significantly associated with anterior tibial translation. In the stratified subgroup analysis and multivariable regression analysis, positive uncovered medial meniscus sign consistently showed a significant association with anterior tibial translation and generated an additional 2.8 mm of anterior tibial translation. Other injuries, including PHMM tear and meniscal ramp lesion, were not associated with anterior tibial translation.The uncovered medial meniscus sign showed a statistically significant correlation with anterior tibial translation and could be a useful marker for the lost brake stop mechanism of PHMM in the ACL-deficient knee.

Although T2-weighted axial magnetic resonance imaging (MRI) has strength in demonstrating morphologic characteristics of the spinal cord in cervical spondylotic myelopathy (CSM), no study has investigated postoperative changes. We aimed to assess postoperative changes on T2-weighted axial MRI using the classification system based on axial imaging in cervical compressive myelopathy (Ax-CCM) and associated impact on outcome in CSM. In total, 250 patients with CSM who underwent decompressive surgery with preoperative and postoperative MRI were included. At first, we investigated the presence of increased signal intensity (SI) in cervical spinal cord on T2-weighted sagittal images. Next, the increased SI was assessed using Ax-CCM on T2weighted axial images. The classifications were type 0, no-signal abnormality; single-level type 1, diffuse; single-level type 2, fuzzy focal; single-level type 3, discrete focal; and two-level. The recovery rates (RRs) of modified Japanese Orthopaedic Association (mJOA) score were evaluated from 5 to 10 months postoperatively. Eighty-seven patients (34.8%) exhibited postoperative changes. Most of postoperative changes were in single-level type 1 and 2. Patterns of changes were resolution, reduced extent, or transition to discrete margin. The most common pattern was resolution in type 1 (23.9%) and transition to discrete margin in type 2 (46.5%). In each group, resolution showed the best RR, but insignificantly (p > 0.05).

Background There are no consensus and guidelines on the optimal interval of repeat epidural steroid injections (ESI) for patients with lumbar herniated intervertebral disc (HIVD) who respond to initial ESI. Purpose To evaluate the effectiveness of ESI in patients with HIVD under a “wait-and-see” policy, i.e. as-needed injections not on a predetermined schedule. Material and Methods A total of 592 patients with lumbar HIVD received spine injections between January and December 2017. After excluding patients with excellent (no pain) or poor (>70% residual symptoms) response in the two- or three-week pain assessment, the data of 141 responders were analyzed (60 men, 73 women; age = 50.55±17.25 years). We divided patients into wait-and-see (n=124) and early repeat-ESI (n=17) groups, who received repeat ESIs within three weeks. Evaluations of characteristics and outcomes were performed with the chi-square test or independent Student’s t-test. Results Six patients (4.8%) in the wait-and-see group and 1 (5.9%) in the early repeat-ESI group underwent operation within one year ( P=0.85). A mean of 1.52±0.82 ESIs was performed in the wait-and-see and a mean of 2.29±0.47 ESIs in the early repeat-ESI group over one year ( PConclusion A “wait-and-see” policy could be an effective pain management option for patients with lumbar HIVD who respond to initial ESI.

BackgroundThe diagnostic accuracy of magnetic resonance imaging (MRI) is low for detecting a subscapularis tendon tear.PurposeTo identify MRI findings that may predict the presence of a clinically significant subscapularis tendon tear requiring surgical repair.Material and MethodsWe reviewed shoulder MR images of patients who had undergone arthroscopic rotator cuff repair at our institution between June 2018 and May 2019. Patients were divided into two groups: the study group (n = 51), with an intermediate- to high-grade partial thickness tear of the subscapularis tendon suspected on preoperative MRI and intermediate or higher grade of the tendon tear proven on arthroscopy; and the control group (n = 18), with an intermediate- to high-grade partial thickness tear of the subscapularis tendon suspected on preoperative MRI but no tear or low-grade partial thickness tear of the tendon shown on arthroscopy. Preoperative MR images were retrospectively evaluated by two readers for the size of the subscapularis tendon tear, bone reactions at the lesser tuberosity, and long head of the biceps tendon (LHBT) pathology.ResultsThe subscapularis tendon tear measured by reader 2 was larger in the study group than in the control group. The prevalence of a tear ( P = 0.006 for reader 1; P = 0.011 for reader 2) and malposition ( P ConclusionA tear and malposition of the LHBT on MR images may predict the presence of a clinically significant subscapularis tendon tear.

The present study assessed test–retest and inter-observer reliability of diffusion tensor imaging (DTI) in cervical spondylotic myelopathy (CSM), as well as the agreement among measurement methods. A total 34 patients (12 men, 22 women; mean age, 58.7 [range 45–79] years) who underwent surgical decompression for CSM, with pre-operative DTI scans available, were retrospectively enrolled. Four observers independently measured fractional anisotropy (FA) values twice, using three different measurement methods. Test–retest and inter-observer reliability was assessed using intraclass correlation coefficients (ICCs). Overall, inter-observer agreements varied according to spinal cord level and the measurement methods used, and ranged from poor to excellent agreement (ICC = 0.374–0.821), with relatively less agreement for the sagittal region of interest (ROI) method. The radiology resident and neuro-radiologist group showed excellent test–retest reliability at almost every spinal cord level (ICC = 0.887–0.997), but inter-observer agreements varied from fair to good (ICC = 0.404–0.747). Despite excellent test–retest reliability of the ROI measurements, FA measurements in patients with CSM varied widely in terms of inter-observer reliability. Therefore, DTI parameter data should be interpreted carefully when applied clinically.

Heavily T2-weighted MR myelography (HT2W-MRM) is emerging as an alternative approach for detection and follow up of CSF leaks. We aimed to assess epidural blood patch (EBP) treatment outcome when using HT2W-MRM as the primary modality for detecting CSF leak and planning EBP placement in routine clinical practice. Since 2018, patients at our institute suspected of having CSF leak, routinely HT2W-MRM instead of CT myelography to determine presence of the leak and identify the EBP target site. Fifty-nine consecutive patients suspected of having a CSF leak underwent HT2W-MRM. After excluding patients with subdural hematoma and poor image quality, 26 (10 men, 16 women; mean age 44.92 ± 12.6 years) patients were included in this study. Patients received EBP on the basis of HT2W-MRM assessments and clinical assessment. Imaging findings and clinical outcome were evaluated. CSF leak was identified in 21 patients (80.8%, 21/26) based HT2W-MRM. Most cases were graded on a confidence scale as CSF leak definitely (n = 13) or probably (n = 3) present. Successful clinical EBP treatment was achieved in 14 of 17 patients (82.4%) after first targeted EBP, and patient symptoms significantly improved after treatment (numerical rating score 6.4 before EBP, 1.3 after EBP, P 0.001). HT2W-MRM based EBP are the rational and effective choices for CSF leak treatment in routine clinical practice.

Purpose To evaluate the ultrasonographic characteristics of steatocystomas focusing on the features that aid in differentiating them from epidermal inclusion cysts and lipomas. Materials and Methods The ultrasonographic findings of 14 histologically proven steatocystomas in 10 patients were retrospectively reviewed. The following features were assessed: the layer of involvement, shape, margin, echogenicity, posterior acoustic features, and the presence of a visible wall or intralesional striations. The findings were compared with those of subcutaneous lipomas and epidermal inclusion cysts to identify those findings that aid in the differential diagnosis of steatocystomas. Results The majority of steatocystomas appeared as a subcutaneous mass (n = 6, 42.9%) or a mass involving both the dermal and subcutaneous layers (n = 6, 42.9%). Steatocystomas exhibited a well-defined smooth margin (n = 12, 85.7%) and homogeneous echogenicity (n = 9, 64.3%), and showed no specific posterior acoustic features (n = 9, 64.3%). The most important features that differentiated steatocystomas from epidermal inclusion cysts were a homogeneous internal echotexture (p = 0.009) and absent or less prominent posterior acoustic enhancement (p < 0.001). The features that distinguished steatocystomas from lipomas were the margin (p < 0.001), echogenicity (p = 0.034), internal echotexture (p = 0.004), and the absence of intralesional striations (p < 0.001). Conclusion Steatocystomas appeared as well-defined homogeneous masses with mild or absent posterior acoustic enhancement.

Objective Poly(lactide-co-glycolide) (PLGA) nanoparticles are promising materials for the development of new drug-releasing systems. The purpose of this study was to evaluate the in vivo retention time of materials loaded in nanoparticles as compared with that of the material alone by in vivo imaging in nude mice. Materials and Methods Mice (n = 20) were injected with 0.1 mL fluorescent material 1,1'-dioctadecyl-3,3,3',3' tetramethylindotricarbocyanine iodide (DiR)-loaded PLGA nanoparticles (200 nm) into the right paraspinal muscle, and the same volume of pure DiR solution was injected into the left paraspinal muscle. Fluorescence images were obtained using an in vivo optical imaging system. Fluorescent images were taken 1 day after the injection, and seven more images were taken at 1-week intervals. Image analysis was done with ImageJ program, and one region of interest was chosen manually, which corresponded to the highest signal-intensity area of fluorescence signal intensity. Results After 7 weeks, 12 mice showed a right-sided dominant signal, representing the DiR loaded PLGA nanoparticles; 5 mice showed a left-side dominant signal, representing the free DiR solution; and 3 mice showed no signal at all beginning 1 day after the injection. During the 7-week period, the mean signal intensities of the free DiR solution and DiR-loaded PLGA nanoparticles diverged gradually. On day 1, the mean signal intensity of free DiR solution was significantly higher than that of DiR-loaded PLGA (p < 0.001). Finally, by week 7, DiR-loaded PLGA express significantly high signal intensity compared with free DiR solution (p = 0.031). Conclusion The results of the current study suggested that therapeutic agents bound to PLGA nanoparticles may exhibit prolonged retention times.

We retrospectively evaluated the technical success rate and long-term efficacy of fluoroscopy-guided synovial cyst rupture followed by an intra-articular steroid injection at the post-laminectomy lumbar facet.We selected subjects who had undergone a fluoroscopy-guided synovial cyst rupture with simultaneous intra-articular steroid injection within 6 months of MRI and demonstrated a symptomatic facet joint synovial cyst at the level of a previous lumbar laminectomy. Fourteen patients were enrolled, and we determined whether cyst rupture and symptom improvement were achieved after each procedure. The degrees of symptom improvement were categorized into 4: 1) symptoms improved (30% or more reduction, based on pre-procedural and post-procedural Numerical Pain Rating Scale scores), 2) symptoms not improved, 3) patient underwent surgery after injection, and 4) loss of follow-up.The success rate of percutaneous synovial cyst rupture decreased with repeated procedures (62.5% for the first procedure and 0% to 33.3% for additional procedures). However, 80% of the patients had symptom improvement with the procedures, overall. The surgery rate was 14.3% in 14 patients.For patients with post-laminectomy symptomatic lumbar facet joint synovial cysts, fluoroscopy-guided synovial cyst rupture with intra-articular steroid injection may be an effective and less invasive treatment before considering a surgical approach.요추 후궁절제술 시행 부위 후관절 활액낭에 대해 투시유도 하 경피적 낭종파열술 및 스테로이드 주입술을 시행 받은 환자에 관하여 후향적으로 시술의 성공률 및 임상적 효과를 분석하였다.투시유도 하 경피적 후관절 낭종파열술과 관절 내 스테로이드 주입술을 시행 받은 환자이면서, 시술 전 6개월 이내 촬영한 요추 자기공명영상 상 이전 후궁절제술 부위와 후 관절 활액낭종의 위치가 일치하는 것이 증명된 환자, 그리고 그 낭종의 위치가 신경학적 증상을 설명하는 것으로 판단되는 환자를 대상(14명)으로 하였으며 시술 후 낭종파열의 성공 유무와 증상의 호전 정도를 조사하였다.시술이 반복될수록 낭종파열의 성공률은 감소하였지만(첫 시술에서는 62.5%, 그 이후의 시술에서는 0~33%), 80%의 환자가 시술 후 증상 호전을 보였다. 추적관찰 기간 내 낭종에 대한 수술률은 14.3%였다.요추 후궁절제술 시행 부위 후관절 활액낭에 대한 투시유도 하 경피적 낭종파열술 및 스테로이드 주입술은 효과적인 치료 방법으로서, 수술적 치료를 고려하기 전에 먼저 시도해 볼 수 있다.

To identify the findings on magnetic resonance imaging most strongly associated with meniscal ramp lesions in patients with an anterior cruciate ligament tear. Seventy-eight consecutive patients (mean age, 33.7 years; 64 male, 14 female) with an arthroscopically proven anterior cruciate ligament tear were included in this retrospective study. The presence of the following six features on magnetic resonance images were recorded: complete fluid filling between the posterior horn of the medial meniscus and the capsule margin; edema affecting the posterior capsule; irregularity of the medial meniscus at the posterior margin; fluid at the periphery of the medial meniscus; the corner notch sign; and a vertical tear at the medial meniscus. Findings at arthroscopy served as the reference standard. Diagnostic accuracy, sensitivity, and interobserver agreement were calculated. Seven ramp lesions were noted on arthroscopy (9%). Findings of irregularity at the posterior margin (p = 0.001) and complete fluid filling between the posterior horn of the medial meniscus and the capsule margin (p = 0.004) on magnetic resonance imaging were significantly associated with the presence of a ramp lesion. With the irregularity at the posterior margin, sensitivity was 86% and specificity was 79%. Complete fluid filling sign showed sensitivity of 57% and specificity of 92%. Concordance of the two readers for the six magnetic resonance imaging features was fair to very good (k = 0.38–0.91). Irregularity at posterior margin and complete fluid filling were most sensitive findings for detecting of a ramp lesion on magnetic resonance imaging.

Objective To compare the T1-weighted spectral presaturation with inversion-recovery sequences (T1 SPIR) with T2-weighted turbo spin-echo sequences (T2 TSE) on 3T magnetic resonance arthrography (MRA) in the evaluation of the subscapularis (SSC) tendon tear with arthroscopic findings as the reference standard. Materials and methods This retrospective study included 120 consecutive patients who had undergone MRA within 3 months between April and December 2015. Two musculoskeletal radiologists blinded to the arthroscopic results evaluated T1 SPIR and T2 TSE images in separate sessions for the integrity of the SSC tendon, examining normal/articular-surface partial-thickness tear (PTTa)/full-thickness tear (FTT). Diagnostic performance of T1 SPIR and T2 TSE was calculated with arthroscopic results as the reference standard, and sensitivity, specificity, and accuracy were compared using the McNemar test. Interobserver agreement was measured with kappa (κ) statistics. Results There were 74 SSC tendon tears (36 PTTa and 38 FTT) confirmed by arthroscopy. Significant differences were found in the sensitivity and accuracy between T1 SPIR and T2 TSE using the McNemar test, with respective rates of 95.9-94.6% vs. 71.6-75.7% and 90.8-91.7% vs. 79.2-83.3% for detecting tear; 55.3% vs. 31.6-34.2% and 85.8% vs. 78.3-79.2%, respectively, for FTT; and 91.7-97.2% vs. 58.3-61.1% and 89% vs. 78-79.3%, respectively, for PTTa. Interobserver agreement for T1 SPIR was almost perfect for T1 SPIR (κ = 0.839) and substantial for T2 TSE (κ = 0.769). Conclusion T1-weighted spectral presaturation with inversion-recovery sequences is more sensitive and accurate compared to T2 TSE in detecting SSC tendon tear on 3T MRA.

Study design Case series study. Objective The aim was to investigate the incidence of retro-odontoid pseudotumor in patients with atlantoaxial instability (AAI) and evaluate pseudotumor regression after posterior fixation. Summary of background data The incidence of retro-odontoid pseudotumor in atlantoaxial instability patients remains uncertain. Moreover, the regression of retro-odontoid pseudotumor after posterior fixation in patients with various underlying diseases needs to be further investigated. Methods From July 2004 to August 2015, 175 patients with AAI underwent posterior fixation operations at our institution. After excluding 11 patients (previous operation, n = 4; history of tumor, n = 7), the final study population comprised 164 patients. The final study population was categorized according to their underlying diseases (rheumatoid arthritis [RA], os odontoideum, atlanto-occipital assimilation, dens fracture, AAI of unknown cause, etc.) and age (adult and pediatric groups). The incidence of retro-odontoid pseudotumor in each group was analyzed. Pre- and postoperative magnetic resonance or computed tomography images were reviewed to assess its regression following surgery. Results Of the 164 patients included, 38 had retro-odontoid pseudotumor (23.2%). Three were diagnosed with RA and the rest were non-RA patients including os odontoideum (n = 12), dens fracture (n = 6), atlanto-occipital assimilation (n = 4), Morquio syndrome (n = 1), and AAI of unknown cause (n = 12). Pseudotumor size regressed in all 38 patients after atlantoaxial posterior fixation. There was a statistically significant decrease in pseudotumor size (the length between the anterior border of the odontoid process to the posterior border of the pseudotumor) from a mean length of 17.7 to 14.9 mm (P Conclusions The patients had various underlying diseases and the overall incidence of retro-odontoid pseudotumor in patients with symptomatic AAI was 23.2% at our institution during the past 11 years. All patients who underwent posterior fixation for AAI showed a statistically significant decrease in pseudotumor size. Level of evidence 4.

The objective of this study is to evaluate the effect of the metal artifact reduction algorithm for orthopedic implants (O-MAR) on CT image quality for patients with reverse total shoulder arthroplasty (RTSA), with emphasis placed on the evaluation of bone in the vicinity of prostheses.Sixty-five patients who underwent CT scanning after RTSA were enrolled in the study. Two radiologists analyzed the images reconstructed with filtered back projection (FBP) with or without O-MAR processing. Images were evaluated to determine the degree of streaking artifacts, the confidence in depicting various structures around the prosthesis, and the presence of pseudolesions. The mean CT number and SD of the selected ROIs placed in the greater tuberosity, glenoid bone, and deltoid muscle were recorded. For measurements from the greater tuberosity and glenoid bone, the frequency with which the measurement met the typical CT number of bone was calculated.O-MAR images showed less metal streak artifact and noise and provided better visualization of the axillary neurovascular bundle compared with FBP images, with a statistically significant difference (p0.001 for all). FBP images were found to be statistically significantly better than O-MAR images, offering better visualization of bone cortex, bone trabeculae, and the bone-prosthesis interface (p0.001 for all). Scapular pseudonotching was observed on 4.6% of FBP images and 36.9% of O-MAR images. The pseudocemented appearance was noted on 47.7% of O-MAR images but was not seen on FBP images.The use of O-MAR improved CT image quality for patients with RTSA in the aspect of metal artifact reduction and soft-tissue profile. However, O-MAR tends to degrade depiction of the bone trabeculae and bone cortex and generate new artifacts, including a pseudocemented appearance and scapular pseudonotching.

To evaluate the correlation between the maximum standardised uptake value (SUVmax) from bone single-photon-emission computed tomography/computed tomography (SPECT/CT) and other imaging parameters for medial compartment osteoarthritis (OA) of the knee.Patients (n=26; male:female=2:24; age, 55.3±5.8 years) underwent quantitative knee SPECT/CT using technetium-99m (Tc-99m) hydroxymethylene diphosphonate (HDP) before surgical operation for medial OA of the knee. SUVmax was calculated using dedicated quantitative software. Visual grades of tracer uptake on bone SPECT/CT and Kellgren-Lawrence (KL) OA scores on plain radiographs were assessed using a five-point scale. Magnetic resonance imaging (MRI) scores (n=22) and patient symptom scores were also assessed.The operated knees (n=34) had a greater SUVmax than the non-operated knees (n=18) in the medial compartment (14.1±6.1 versus 5.3±4.4, p0.0001). In the medial compartment, the SUVmax was significantly correlated with SPECT/CT visual grades (rho=0.794, p0.0001), KL scores (rho=0.703, p0.0001), and MRI scores (rho=0.714-0.808, p≤0.0002); however, SUVmax and other imaging parameters were not correlated with patient symptom scores (p0.05).The SUVmax of quantitative bone SPECT/CT was highly correlated with traditional imaging parameters for medial compartment OA severity of the knee. Quantitative bone SPECT/CT is a promising imaging technique for the objective assessment of knee OA.

To evaluate the diagnostic value of MR arthrography (MRA) in diagnosing instability of the LHBT in patients with rotator cuff tendon tear. The MR arthrograms of 101 patients were retrospectively reviewed and correlated with arthroscopic findings as the standard reference. Images were evaluated for (1) the integrity of the LHBT, (2) the position of the LHBT (subluxation/dislocation on axial images, inferior displacement on oblique sagittal image) and (3) the integrity of the biceps pulley (SGHL, supraspinatus and subscapularis tendon adjacent to the rotator interval). The integrity of the LHBT was correctly classified in 74.3% (75/101) and 66.3% (67/101) by readers 1 and 2, respectively. The diagnosis of LHBT instability could be made on axial images with a sensitivity of 82.6% and 73.9% and specificity of 69.9% and 87.7%, whereas the displacement sign on sagittal images had a sensitivity of 73.9% and 78.3% and a specificity of 64.4% and 61.6%, respectively. Assessing the integrity of the SGHL had a sensitivity of 60.9 and 93.3% and a specificity of 70.4 and 75.0%, respectively. By combining the different image findings, the accuracy in assessing LHBT instability was 80.9 and 90.5% with a sensitivity of 60.9 and 86.7% and specificity of 83.1 and 91.8%, respectively. Individual image findings may have a limited role in diagnosing LHBT instability in patients with rotator cuff tendon tear. The accuracy of MRA may be improved by assessing the integrity of the biceps pulley structures along with the position of the LHBT on both axial and sagittal images.

Advances in imaging and the development of injection techniques have enabled spinal intervention to become an important tool in managing chronic spinal pain. Epidural steroid injection (ESI) is one of the most widely used spinal interventions; it directly delivers drugs into the epidural space to relieve pain originating from degenerative spine disorders-central canal stenoses and neural foraminal stenoses-or disk herniations. Knowledge of the normal anatomy of the epidural space is essential to perform an effective and safe ESI and to recognize possible complications. Although computed tomographic (CT) or combined CT-fluoroscopic guidance has been increasingly used in ESI, conventional fluoroscopic guidance is generally performed. In ESI, drugs are delivered into the epidural space by interlaminar or transforaminal routes in the cervical spine or by interlaminar, transforaminal, or caudal routes in the lumbar spine. Epidurography is usually performed before drug delivery to verify the proper position of the needle in the epidural space. A small amount of contrast agent is injected with fluoroscopic guidance. Familiarity with the findings on a typical "true" epidurogram (demonstrating correct needle placement in the epidural space) permits proper performance of ESI. Findings on "false" epidurograms (demonstrating incorrect needle placement) include muscular staining and evidence of intravascular injection, inadvertent facet joint injection, dural puncture, subdural injection, and intraneural or intradiscal injection. ©RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on December 22, 2016.

Gadolinium-based contrast agents with a double negative charge produced better contrast between normal and degenerated cartilage on delayed gadolinium-enhanced MR images than did those with a single negative charge and nonionic gadolinium-based contrast agents at the same concentration, and gadobenate dimeglumine may be useful as an alternative to gadopentetate dimeglumine for delayed gadolinium-enhanced MR imaging of cartilage.

Purpose Inflammatory and neoplastic intramedullary spinal cord lesions have overlapping clinical features, and it is occasionally difficult to distinguish one from the other on conventional magnetic resonance imaging. We aimed to compare diffusion tensor imaging findings between inflammatory and neoplastic intramedullary spinal cord lesions, with a specific focus on patterns of fiber tracking. Materials and Methods Diffusion tensor imaging was performed in patients with either inflammatory or neoplastic intramedullary spinal cord lesions. The fiber tracking patterns (categorized as “intact,” “displaced,” or “interrupted”) were compared between these two groups. Results Eight patients were included in the study: 5 patients with pathologically or clinically confirmed inflammatory lesions and 3 patients with pathologically or clinically confirmed neoplastic lesions. Among the 5 patients with inflammatory lesions, 2 patients exhibited the displaced pattern and 3 patients exhibited the intact pattern. Among the 3 patients with neoplastic lesions, 1 patient exhibited the intact pattern, 1 patient exhibited the displaced pattern, and 1 patient exhibited the interrupted pattern. Conclusion In this study, inflammatory and neoplastic intramedullary spinal cord lesions were not clearly differentiated by fiber tracking; both conditions can present with overlapping features such as displaced fibers. The exclusion of inflammatory conditions based on the presence of displaced fibers in fiber tracking images should be avoided.

We used magnetic resonance imaging (MRI) to evaluate where articular degeneration begins and which ligaments are most often involved in the early clinical stage first carpometacarpal joint (CMCJ-1) osteoarthritis. We retrospectively analyzed the MRI findings of 26 patients with early clinical stage CMCJ-1 osteoarthritis and no radiologic abnormalities and 19 control patients without CMCJ-1 pain or osteoarthritis who underwent MRI for dorsal or ulnar wrist pain. Two observers blinded to group and clinical findings independently assessed the presence of chondral defects in four quadrants of the CMCJ-1: volar-ulnar (VU), volar-radial (VR), dorso-ulnar (DU), and dorso-radial (DR). The integrity of the four major ligaments of the CMCJ-1, i.e., the anterior oblique ligament (AOL), the intermetacarpal ligament (IML), the posterior oblique ligament (POL), and the dorsal radial ligament (DRL), was assessed. The observer reliability was analyzed using Cohen’s kappa coefficient. The prevalence of cartilage lesions and ligament abnormalities in the osteoarthritic and control patients was compared using Fisher’s exact test. Cartilage lesions were significantly more common in the VU quadrant of the trapezium in the osteoarthritic patients than in the control patients (17/26 vs. 2/19; P = 0.002). AOL abnormalities were more common in the osteoarthritic patients than in the control patients (14/26 vs. 3/19; P = 0.009). The MRI findings of early clinical stage CMCJ-1 osteoarthritis commonly demonstrated cartilage lesions in the VU quadrant of the trapezium and ligament abnormalities in the AOL.

To develop a deep learning algorithm that can rule out significant rotator cuff tear based on conventional shoulder radiographs in patients suspected of rotator cuff tear. The algorithm was developed using 6793 shoulder radiograph series performed between January 2015 and June 2018, which were labeled based on ultrasound or MRI conducted within 90 days, and clinical information (age, sex, dominant side, history of trauma, degree of pain). The output was the probability of significant rotator cuff tear (supraspinatus/infraspinatus complex tear with > 50% of tendon thickness). An operating point corresponding to sensitivity of 98% was set to achieve high negative predictive value (NPV) and low negative likelihood ratio (LR−). The performance of the algorithm was tested with 1095 radiograph series performed between July and December 2018. Subgroup analysis using Fisher’s exact test was performed to identify factors (clinical information, radiography vendor, advanced imaging modality) associated with negative test results and NPV. Sensitivity, NPV, and LR− were 97.3%, 96.6%, and 0.06, respectively. The deep learning algorithm could rule out significant rotator cuff tear in about 30% of patients suspected of rotator cuff tear. The subgroup analysis showed that age

Background: To develop a rabbit epidural steroid injection (ESI) model for analyzing steroid retention in the tissue, and to assess the difference in steroid retention in the model according to the location and time elapsed after ESI. Methods: Fluoroscopy-guided ESI was performed using the interlaminar approach between the lowest two lumbar segments in 13 female New Zealand white rabbits. Four rabbits were allocated to each of three different groups according to the time of sacrifice: 3, 7, and 15 days post-ESI; the remaining rabbit was sacrificed immediately post-ESI to obtain baseline data. After sacrifice, two segments were harvested: the lowest two lumbar vertebrae and another two lumbar vertebrae immediately above these. The residual steroid amount (RSA) and residual steroid concentration (RSC) in the collected spinal columns were analyzed. A linear mixed model was used to compare RSAs and RSCs between the injected and adjacent segments, and among the number of days until sacrifice; P < 0.05 was considered statistically significant. Results: Both RSA and RSC of the injected segment were significantly higher than those of the adjacent segment (P < 0.001, both). The RSA and RSC significantly decreased over time (P = 0.009 and P = 0.016, respectively). Conclusions: The developed rabbit ESI model verified that significantly more steroid was retained at the injected segment than at the adjacent segment and the residual steroid decreased over time. This model could be useful not only for comparing current steroid medications, but also for developing new, better steroid formulations.

BackgroundAlthough both 1.5-Tesla (T) and 3-T magnetic resonance imaging (MRI) are widely used for the diagnosis of cervical spondylotic myelopathy (CSM), there have been no comparative studies.Pur...

Hemangioblastomas are low-grade, highly vascular tumors that are usually associated with von Hippel-Lindau syndrome. Hemangioblastomas most commonly occur in the cerebellum, and intradural extramedullary hemangioblastoma of the cauda equina is very rare, especially in patients without von Hippel-Lindau syndrome. Herein, we report a case of intradural extramedullary hemangioblastoma of the cauda equina that was not associated with von Hippel- Lindau syndrome, with a focus on its imaging characteristics and differential diagnoses. We compared the clinical presentation and imaging features of our case with those of previously reported cases in the review of the literature.

Purpose To investigate the effect of fat suppression on T2 mapping of the articular cartilage in the porcine knee joint using magnetic resonance imaging (MRI). Materials and Methods Eleven porcine knee joints were harvested en bloc with intact capsules. We performed T2 mapping of the articular cartilage in the medial femoral condyle at 3T either with (fat-suppressed T2 mapping) or without (conventional T2 mapping) fat suppression in the sagittal plane under two frequency-encoding directions: from superior to inferior (SI) and inferior to superior (IS). Two observers measured the T2 values of the medial femoral condyle cartilage in four regions: in the anterior oblique, central horizontal, posterior oblique, and posterior vertical portions. We evaluated reproducibility of the fat-suppressed and conventional T2 mapping by changing the frequency-encoding direction. Results The mean T2 values of fat-suppressed T2 mapping were significantly lower than those of conventional T2 mapping for five of eight comparisons (P < 0.017). The mean T2 values between fat-suppressed T2-SI and fat-suppressed T2-IS did not differ significantly in any region (P = 0.077–0.873). However, the mean T2 values of conventional T2-SI were significantly lower compared with conventional T2-IS in three of the regions (P < 0.05). The intraclass correlation coefficient (ICC) between the two fat-suppressed T2 maps was higher than the ICC between the two conventional T2 maps (0.276–0.800 vs. –0.032–0.455) for three regions. Conclusion Compared with conventional T2 mapping, fat-suppressed T2 mapping provides lower T2 values of the articular cartilage and more reproducible results for the porcine knee joint. J. Magn. Reson. Imaging 2016.

Objective To assess the learnability of two magnetic resonance imaging (MRI) grading systems for lumbar central canal stenosis based on inter-observer agreement and test-retest reliability of doctors with no prior knowledge of the two systems. Materials and methods Two clinical fellows, one novice radiology resident, one neurosurgeon, and one orthopedic surgeon, who were unaware of the two qualitative MRI grading systems prior to this study, acquainted themselves with the teaching files. All five observers independently assessed the LCCS grade of 70 patients using T2-weighted axial magnetic resonance images at the L2-3, L3-4, L3-4, and L5-S1 disc levels. Analysis was performed twice at an interval of two months. Results The inter-observer agreement among all five readers was excellent and test-retest reliability was moderate to excellent for both the Schizas and Lee systems. Positive percentage agreements were found to be over 0.8 in almost all observers with relatively narrow 95% confidence limits. Conclusion Both Schizas and Lee MRI grading systems for LCCS are reliable grading systems, and can be used as a learnable method for both clinicians and radiologists.

Purpose To explore the feasibility of postoperative high-tesla DTI in CSM and optimize its acquisition parameters using both single-shot (SS) echo-planar imaging (EPI) and multi-shot (MS) EPI, and to evaluate correlation between image degradation and operative methods. Method We enrolled twenty-seven patients with CSM scheduled for MRI at one month after cervical operations who were divided into three groups; 11 patients in group 1; 11 in group 2; and 5 in group 3. The patient in each group underwent two sets of DTI using both SS-EPI and MS-EPI with different diffusion gradient directions. Qualitative and quantitative analysis of fractional anisotropy (FA) and color-coding maps were performed to evaluate image distortion and spinal cord visualization and were compared between SS- and MS-EPI. DTI indices, including the number of reconstructed fibers, mean apparent diffusion coefficient (ADC) values, and mean FA values, were acquired. Results In the metallic segment, MS-EPI with 6 diffusion gradients showed significantly less distortion and better cord visualization than SS-EPI. Fiber tracking was also superior with MS-EPI sequences. Scores in the subjective motor improvement scale showed a moderately positive correlation correlated only with the mean ADC at 1 month postoperatively. Regarding the operation methods, DTI in patients who underwent anterior cervical discectomy and fusion showed the least image distortion and 100 % success rate of fiber tractography. Conclusions Compared with SS-EPI, MS-EPI with motion correction significantly improves image distortions and increases the success rate of fiber tractography in CSM patients with metal implants.

Purpose To describe magnetic resonance imaging (MRI) findings in 10 cases of Toxocara canis myelitis and to analyze these findings to aid in the diagnosis of this condition. Materials and Methods From June 2015 to March 2018, we retrospectively analyzed the electronic medical records and MR images of patients who were diagnosed with Toxocara canis myelitis. The analysis of the MR images was based on a discussion between an experienced spinal radiologist and a radiology resident. Results This study classified MRI findings into the following two types. Type 1 was defined as central and diffuse T2 high signal intensity on the axial plane, which was observed in 50% of all cases. All lesions showed avid enhancement, mostly in the posterolateral or posterior region (4 cases, 80%). Type 2 was defined as wedge-shaped or focal T2 high signal intensity in the posterolateral or posterior region and corresponded to the remaining 50% of the cases. In this case, the extent of the lesion was relatively small and contrast enhancement was observed in only one case. Conclusion This study revealed that various imaging findings could be observed in cases of Toxocara canis myelitis, and the findings were classified into two types.

Spontaneous intracranial hypotension (SIH), caused by CSF leaks, can trigger headaches, and is treated using epidural blood patch (EBP) procedures. We aimed to determine the effectiveness of a newly devised two-site blind EBP procedure as the initial treatment for SIH and compare its effectiveness with that of conventional targeted EBP. We retrospectively reviewed data for 116 patients who underwent EBP for SIH between November 2013 and April 2017. Patients were divided into two groups: those who initially received two-site blind EBP (n = 28) at the cervicothoracic (C7/T1) and thoracolumbar junctions (T12/L1) for sealing CSF leaks at all levels, and those who received targeted EBP after CT myelography (n = 88). The initial recovery status and the need for additional blood patches were evaluated. In total, 71.4% and 69.3% patients in the two-site blind EBP and targeted EBP groups, respectively, experienced complete relief after the first patch (p > .05); collectively, 89.3% and 96.6% patients, respectively, experienced complete or partial relief after the first patch (p > .05). A second EBP was required by 35.7% and 29.5% patients in the two-site blind EBP and targeted EBP groups, respectively, with no significant between-group difference (p > .05). All patients ultimately experienced relief; a few required up to four patches. We observed similar outcomes after initial two-site blind EBP and targeted EBP. Therefore, two-site blind EBP is an effective alternative to conventional targeted EBP and a potential initial patch of choice for SIH treatment.