Interlaminar versus transforaminal epidural steroid injections: a review of efficacy and safety.

Spine intervention is an important treatment option for the management of spinal pain, and the numbers of the most representative epidural steroid injection (ESI) procedures performed are expected to increase significantly in the future along with increased life expectancy and the increasing prevalence of spinal disorders. Therefore, it is important to understand the efficacy of ESIs according to each spinal disorder they are administered to treat, and one must be familiar with the possible complications. In fact, although numerous ESI-related articles have been published, there is still considerable controversy regarding the efficacy of ESI procedures. Furthermore, due to the rarity of serious complications, most instances have been recorded in the form of case reports. In this article, we aimed to review the indications of cervical and lumbar ESIs and to compare interlaminar ESI (ILESI) and transforaminal ESI (TFESI) techniques in terms of analgesic efficacy, possible complications, and safety profiles. This article includes opinions based on the authors' experience with ESI indications and efficacy, and presents practical tips for coping with specific situations related to each complication. By combining the dedicated anatomical understanding of radiologists with image-guided interventions, ESI is expected to stand out in the rapidly expanding field of spine intervention.

Statistical analysis of hard X-ray radiation at the PAL-XFEL facility performed by Hanbury Brown and Twiss interferometry.

A Hanbury Brown and Twiss interferometry experiment based on second-order correlations was performed at the PAL-XFEL facility. The statistical properties of the X-ray radiation were studied within this experiment. Measurements were performed at the NCI beamline at 10 keV photon energy under various operation conditions: self-amplified spontaneous emission (SASE), SASE with a monochromator, and self-seeding regimes at 120 pC, 180 pC and 200 pC electron bunch charge. Statistical analysis showed short average pulse duration from 6 fs to 9 fs depending on the operational conditions. A high spatial degree of coherence of about 70-80% was determined in the spatial domain for the SASE beams with the monochromator and self-seeding regime of operation. The obtained values describe the statistical properties of the beams generated at the PAL-XFEL facility.

Effectiveness of epidural steroid injection in patients with lumbar herniated intervertebral disc under a "wait-and-see" policy.

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 (P<0.001). The time interval between the first and second ESIs was longer in the wait-and-see group than in the early repeat-ESI group (97.15 vs. 15.47 days, P<0.001). Seventy-eight patients (62.9%) in the wait-and-see group could control their pain with a single ESI. CONCLUSION: A "wait-and-see" policy could be an effective pain management option for patients with lumbar HIVD who respond to initial ESI.

Morphological changes in the superficial medial collateral ligament on knee MR imaging: association with medial meniscal extrusion and posterior root medial meniscus abnormality.

OBJECTIVE: To assess the association between morphological changes in the superficial medial collateral ligament and meniscal extrusion with medial meniscus posterior root tear. MATERIALS AND METHODS: From January 1, 2018, to December 31, 2019, 124 patients who underwent knee MRI within 90 days prior to knee surgery and whose medial meniscus surgically proved intact, with posterior root tear or posterior horn tear, were enrolled. Two radiologists who were blinded to the surgical results assessed the morphological changes in the superficial medial collateral ligament, including thickness, bowing angle, and presence of signal intensity alteration, and medial meniscus extrusion, according to the presence of tears in the posterior root of the medial meniscus or posterior horn of the medial meniscus using the chi-square test, one-way ANOVA, and Cohen's kappa test. RESULTS: Thirty-six posterior root tears, 31 posterior horn tears, and 57 intact medial menisci were observed surgically. The mean values of thickness showed no significant differences among the three groups. The bowing angle was significantly higher in the posterior root tear than in the posterior horn tear (reader 1 = 0.001, reader 2 = 0.002) and normal meniscus groups (readers 1 and 2 < 0.001). The percentage of superficial medial collateral ligament signal intensity alteration and meniscal extrusion was highest in the group with posterior root of the medial meniscus tear (80.6% and 94.4%, respectively) and lowest in the group with normal medial meniscus (17.5% and 10.5%, respectively). CONCLUSION: Morphological changes in the superficial medial collateral ligament and meniscal extrusion were associated with medial meniscus posterior root tears.

Predicting the clinically significant subscapularis tendon tear: malposition and tear of the long head of the biceps tendon on shoulder magnetic resonance imaging.

BACKGROUND: The diagnostic accuracy of magnetic resonance imaging (MRI) is low for detecting a subscapularis tendon tear. PURPOSE: To identify MRI findings that may predict the presence of a clinically significant subscapularis tendon tear requiring surgical repair. MATERIAL AND METHODS: We 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. RESULTS: The 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 < 0.001 for both readers) of the LHBT were significantly greater in the study group. CONCLUSION: A tear and malposition of the LHBT on MR images may predict the presence of a clinically significant subscapularis tendon tear.

Intra-articular facet joint steroid injection-related adverse events encountered during 11,980 procedures.

OBJECTIVES: To analyze the incidence and characteristics of intra-articular facet joint injection (FJI)-related adverse events requiring hospitalization and emergency room visits. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. KEY POINTS: • 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.

Ruling out rotator cuff tear in shoulder radiograph series using deep learning: redefining the role of conventional radiograph.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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 < 60 years (p < 0.001), non-dominant side (p < 0.001), absence of trauma history (p = 0.001), and ultrasound examination (p < 0.001) were associated with negative test results. NPVs were higher in patients with age < 60 years (p = 0.024) and examined with ultrasound (p < 0.001). CONCLUSION: The deep learning algorithm could accurately rule out significant rotator cuff tear based on shoulder radiographs. KEY POINTS: • The deep learning algorithm can rule out significant rotator cuff tear with a negative likelihood ratio of 0.06 and a negative predictive value of 96.6%. • The deep learning algorithm can guide patients with significant rotator cuff tear to additional shoulder ultrasound or MRI with a sensitivity of 97.3%. • The deep learning algorithm could rule out significant rotator cuff tear in about 30% of patients with clinically suspected rotator cuff tear.

Association of meniscal flounce in the knee with the pattern and location of meniscal tear, concomitant ligamentous injury, amount of knee joint effusion, and flexion and rotation angles: a magnetic resonance evaluation.

OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Hard X-ray self-seeding commissioning at PAL-XFEL.

A wake monochromator based on a large-area diamond single crystal for hard X-ray self-seeding has been successfully installed and commissioned in the hard X-ray free-electron laser (FEL) at the Pohang Accelerator Laboratory with international collaboration. For this commissioning, the self-seeding was demonstrated with a low bunch charge (40 pC) and the nominal bunch charge (180 pC) of self-amplified spontaneous emission (SASE) operation. The FEL pulse lengths were estimated as 7 fs and 29.5 fs, respectively. In both cases, the average spectral brightness increased by more than three times compared with the SASE mode. The self-seeding experiment was demonstrated for the first time using a crystal with a thickness of 30 µm, and a narrow bandwidth of 0.22 eV (full width at half-maximum) was obtained at 8.3 keV, which confirmed the functionality of a crystal with such a small thickness. In the nominal bunch-charge self-seeding experiment, the histogram of the intensity integrated over a 1 eV bandwidth showed a well defined Gaussian profile, which is evidence of the saturated FEL and a minimal electron-energy jitter (∼1.2 × 10-4) effect. The corresponding low photon-energy jitter (∼2.4 × 10-4) of the SASE FEL pulse, which is two times lower than the Pierce parameter, enabled the seeding power to be maximized by maintaining the spectral overlap between SASE FEL gain and the monochromator.

FEL performance achieved at PAL-XFEL using a three-chicane bunch compression scheme.

PAL-XFEL utilizes a three-chicane bunch compression (3-BC) scheme (the very first of its kind in operation) for free-electron laser (FEL) operation. The addition of a third bunch compressor allows for more effective mitigation of coherent synchrotron radiation during bunch compression and an increased flexibility of system configuration. Start-to-end simulations of the effects of radiofrequency jitter on the electron beam performance show that using the 3-BC scheme leads to better performance compared with the two-chicane bunch compression scheme. Together with the high performance of the linac radiofrequency system, it enables reliable operation of PAL-XFEL with unprecedented stability in terms of arrival timing, pointing and intensity; an arrival timing jitter of better than 15 fs, a transverse position jitter of smaller than 10% of the photon beam size, and an FEL intensity jitter of smaller than 5% are consistently achieved.

Performance of a Deep Learning Algorithm in Detecting Osteonecrosis of the Femoral Head on Digital Radiography: A Comparison With Assessments by Radiologists.

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.

Clinical and imaging characteristics of patients with extreme low back pain or sciatica referred for spinal injection.

PURPOSE: To analyze the causes of pain, imaging characteristics, and therapeutic effect of spinal injection in patients with extreme low back pain or sciatica. METHODS: 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. RESULTS: 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 < 50 years of age, while spinal stenosis was the most common in patients ≥ 50 years of age. Women comprised 66.4% of the study population. The majority of lumbar pathologies occurred below L3/4. Spinal injection was found to be effective in 44.2% of cases. Those who responded to the injection showed a significantly lower rate of lumbar surgery within 6 months (P = 0.004). CONCLUSIONS: Those with extreme low back pain or sciatica had clinical and imaging characteristics similar to those with typical low back pain referred for spinal injection. Spinal injection could be an effective method of pain control for patients with extreme low back pain or sciatica.

Non-traumatic ligamentum teres tears: association with MRI morphometry of the hip.

BACKGROUND: The ligamentum teres has been recognized as an important stabilizer of the hip. PURPOSE: We aimed to examine the relationship between non-traumatic ligamentum teres (LT) tear and hip morphometry on magnetic resonance imaging (MRI). MATERIAL AND METHODS: Fifty patients who had undergone hip MRI were included (27 men, 23 women; average age = 54.0 years). The status of the LT and the morphometric hip parameters were assessed, including acetabular anteversion angle (AAA), acetabular depth (AD), acetabular index (AI), lateral center edge angle (LCEA), and extrusion index (EI). The morphometric hip parameters were compared between groups with one-way ANOVA, Student's t-test, and Mann-Whitney U test. RESULTS: A decreased acetabular coverage was noted in the severe tear group compared to the normal group, indicated by a significantly larger AD ( P = 0.001) and smaller LCEA ( P = 0.016). There was a statistically significant difference in the AAA, AD, and LCEA between the normal group and the complete tear group; the AAA was significantly larger ( P = 0.031), the AD was significantly larger ( P = 0.01), and the LCEA was significantly smaller ( P = 0.043) in the complete tear group compared to the normal group. CONCLUSION: There is an association between LT tears and acetabular bony morphology; an insufficient acetabular coverage is associated with complete tear of the LT. As the insufficient acetabular coverage may predispose to ligamentum teres tear, the ligamentum teres should be thoroughly evaluated in those with insufficient acetabular coverage, as a potential cause of hip pain.

The pattern of idiopathic isolated teres minor atrophy with regard to its two-bundle anatomy.

OBJECTIVE: We aimed to analyze the pattern of teres minor atrophy with regard to its two-bundle anatomy and to assess its association with clinical factors. MATERIALS AND METHODS: Shoulder MRIs performed between January and December 2016 were retrospectively reviewed. Images were evaluated for the presence and pattern of isolated teres minor atrophy. Isolated teres minor atrophy was categorized into complete or partial pattern, and partial pattern was further classified according to the portion of the muscle that was predominantly affected. The medical records were reviewed to identify clinical factors associated with teres minor atrophy. RESULTS: Seventy-eight shoulders out of 1,264 (6.2%) showed isolated teres minor atrophy; complete pattern in 41.0%, and partial pattern in 59.0%. Most cases of partial pattern had predominant involvement of the medial-dorsal component (82.6%). There was no significant association between teres minor atrophy and previous trauma, shoulder instability, osteoarthritis, and previous operation. The history of shoulder instability was more frequently found in patients with isolated teres minor atrophy (6.4%), compared with the control group (2.6%), although the difference was not statistically significant. CONCLUSION: Isolated teres minor atrophy may be either complete or partial, and the partial pattern may involve either the medial-dorsal or the lateral-ventral component of the muscle. The imaging findings of partial pattern teres minor atrophy indicate that the two muscle components may have separate innervation.

Epidural steroid injection-related events requiring hospitalisation or emergency room visits among 52,935 procedures performed at a single centre.

OBJECTIVES: To analyse the incidence and type of epidural steroid injection (ESI)-related adverse events, including procedure-related complications and drug-related systemic effects requiring hospitalisation or emergency room (ER) visits. METHODS: This study included 52,935 ESI procedures performed in 22,059 patients in our department from March 2004 to February 2016. Of these, we retrospectively reviewed the cases of 1570 patients (1713 procedures) who were hospitalised or visited the ER within 1 month after ESI. ESI-related events were classified as procedure-related complications, drug-related systemic effects, or of uncertain relationship. Descriptive data are provided; no statistical analysis was performed. RESULTS: There were 244 ESI-related events in 235 patients (males:females = 102:133; mean age: 65.7 years; range: 20-93 years). The incidence of ESI-related events was 0.46% per procedure, including 14 procedure-related complications, 56 drug-related systemic effects, and 174 events of uncertain cause. Of the 52,935 patients, 6 (0.011%) experienced major complications (two spine haematomas and four infections), 1 patient died, and 1 experienced neurological sequelae. CONCLUSIONS: Although major procedure-related complications and drug-related systemic effects of ESI requiring hospitalisation are very rare, infection and haematoma can occur, resulting in serious outcomes. Hence, ESI should be carefully considered in high-risk patients. KEY POINTS: • The incidence of ESI-related events requiring hospitalisation was 0.46%. • The incidence of procedure-related complications was 0.026%. • The incidence of drug-related systemic effects was 0.11%. • The incidence of major complication of ESI was 0.011%. • The major complications were spine infection, haematoma, and sepsis.

Uncovered Medial Meniscus Sign on Knee MRI: Evidence of Lost Brake Stop Mechanism of the Posterior Horn Medial Meniscus.

OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Disproportionate fluid sign as an aid in diagnosing high-grade bursal-sided supraspinatus tendon tear.

Background Deep, high-grade bursal-sided supraspinatus tendon tears are sometimes preoperatively misinterpreted as full-thickness tears on shoulder magnetic resonance imaging (MRI). Purpose To determine the usefulness of disproportionate fluid sign for differentiating high-grade bursal-sided partial-thickness tears from full-thickness tears on conventional MRI. Material and Methods Preoperative MRIs of 198 patients with arthroscopically confirmed high-grade bursal-sided partial-thickness tears and full-thickness tears were independently reviewed by two readers on two occasions. The presence of high-grade bursal-sided partial-thickness tears with a confidence level using a five-point grading scale was assessed based on tear depth alone and also in combination with disproportionate fluid sign, defined as a prominent subdeltoid or subacromial-subdeltoid bursal fluid distension with a relative paucity of effusion in the glenohumeral joint. The sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) were calculated, as well as inter-observer reliability. Results The disproportionate fluid sign was identified in 60/74 (81.2%) bursal-sided partial-thickness tears and 9/124 (7.5%) full-thickness tears. The sensitivity and accuracy of the diagnosis of bursal-sided tear were higher when disproportionate fluid sign was used in conjunction with the tear depth, compared with tear depth alone ( P < 0.001). There was excellent inter-observer agreement for disproportionate fluid sign and deep bursal-sided tear. The AUCs were significantly higher in combination with disproportionate fluid sign. Conclusion The disproportionate fluid sign indicates the presence of a deep, high-grade bursal-sided partial-thickness tear, which can be misinterpreted as a full-thickness tear. Thus, it can provide greater diagnostic assistance to less-experienced radiologists and clinicians.

Efficacy and outcome predictors of fluoroscopy-guided facet joint injection for spondylolysis.

OBJECTIVE: To assess the efficacy of fluoroscopy-guided facet joint injection for symptomatic spondylolysis and to analyze the outcome predictors. MATERIALS AND METHODS: This study included 108 patients who underwent fluoroscopy-guided facet joint steroid injection for symptomatic spondylolysis with follow-up medical records from January 2013 to December 2016. Among them, 47 patients underwent concomitant epidural steroid injection. Response to injection was assessed at the initial follow-up. The symptom-free interval was analyzed using the Kaplan-Meier method. Outcome predictors were statistically analyzed using independent t test and Chi-square test. RESULTS: The facet joint injection was effective in 52 of 108 (48.1%) patients at initial follow-up. Recurrence was reported in 21 of these 52 (40.4%) patients. For the 52 patients in whom facet joint injection was effective, the median symptom-free interval was 298 days (95% confidence interval, 29-567 days). No significant difference was found in the response between the group with facet joint injection only (n = 61) and the group with facet joint injection and additional ESI (n = 47). Additionally, no significant outcome predictors were detected. CONCLUSIONS: Fluoroscopy-guided facet joint injection may potentially be an effective therapy for providing prolonged pain relief and avoiding unnecessary surgery for symptomatic spondylolysis without significant outcome predictors.

MR evaluation of the meniscal ramp lesion in patients with anterior cruciate ligament tear.

OBJECTIVE: To identify the findings on magnetic resonance imaging most strongly associated with meniscal ramp lesions in patients with an anterior cruciate ligament tear. SUBJECTS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: Irregularity at posterior margin and complete fluid filling were most sensitive findings for detecting of a ramp lesion on magnetic resonance imaging.

Delayed Gadolinium-enhanced MR Imaging of Cartilage: A Comparative Analysis of Different Gadolinium-based Contrast Agents in an ex Vivo Porcine Model.

Purpose To compare the delayed gadolinium-enhanced magnetic resonance (MR) imaging of cartilage (dGEMRIC) indexes acquired with different gadolinium-based contrast agents (GBCAs), with emphasis on the difference in electrical charge, and to evaluate the feasibility of the use of GBCAs other than gadopentetate dimeglumine with a double negative charge (Gd-DTPA2-) as alternatives at dGEMRIC. Materials and Methods Intact porcine patellae (n = 44) were divided into four groups according to GBCA used: Gd-DTPA2-, double negative gadobenate dimeglumine (Gd-BOPTA2-), single negative gadoterate meglumine (Gd-DOTA-), and nonionic gadobutrol (Gd-DT-DO3A). Patellae in each group were further assigned to control (n = 3) or trypsin-treated (n = 8) groups and were immersed in GBCA solutions prepared at a concentration of 2.5 mmol/L. T1 maps were acquired at 10-minute intervals at 0-120 minutes. The difference between postcontrast R1 and precontrast R1 (ΔR) and the time ΔR curves were plotted. Patellae were stained with safranin-O to evaluate the proteoglycan content of the cartilage. A linear mixed-effects model was used to analyze the time ΔR curves, and Student t tests and Mann-Whitney U tests were used to compare dGEMRIC indexes between groups. Results The difference in the estimated slopes of the time ΔR curves between control and trypsin-treated groups were greatest with Gd-BOPTA2-, followed by Gd-DTPA2-, Gd-DOTA-, and Gd-DT-DO3A, with differences in the estimated slopes of 0.037, 0.022, 0.018, and 0.011, respectively. The slope difference between control and trypsin-treated groups was significantly greater with Gd-BOPTA2- (P < .001) and significantly smaller with Gd-DT-DO3A (P = .004) in comparison with that with Gd-DTPA2-. Only the GBCAs with double negative charges showed significant differences in both the T1 measured after equilibration of cartilage with GBCA solution and the ΔR at 90 and 120 minutes between the control and trypsin-treated groups. Conclusion Double negative GBCAs produced better contrast between normal and degenerated cartilage than did those with a single negative charge and nonionic GBCAs at the same concentration for dGEMRIC. Because Gd-BOPTA2-, a high-relaxivity GBCA, showed higher contrast than did Gd-DTPA2-, Gd-BOPTA2-may be useful as an alternative GBCA for dGEMRIC. © RSNA, 2016 Online supplemental material is available for this article.