Evaluation of the efficacy and safety of epidural steroid injection using a nonparticulate steroid, dexamethasone or betamethasone:a double-blind, randomized, crossover, clinical trial

Background@#The U.S. Food and Drug Administration has prohibited epidural steroid injection (ESI) with particulate steroids. Thus, this study aimed to compare the efficacy and safety of ESI with two nonparticulate steroids, dexamethasone and betamethasone. @*Methods@#The eligible patients (n = 600) who received ESI (0 week) with dexamethasone (ESI-dexa) or betamethasone (ESI-beta) had follow-up visits at 2, 4, and 8 weeks with a phone interview at 12 weeks. The primary endpoint was the proportion of effective responders without pain or who were much improved at 2 weeks. The secondary endpoints were the proportion of crossover injections at 2 weeks; changes in the visual analog scale (VAS) and disability index scores at 2, 4, and 8 weeks; the number of additional ESIs in 12 weeks; the number of participants having spinal surgery, as well as the incidence of adverse events over the 12 weeks. @*Results@#The proportion of effective responders at 2 weeks was not different between ESI-beta (72/216, 33.3%) and ESI-dexa (63/200, 31.5%; P = 0.670). Adverse events were more common with ESI-dexa (40/200, 20.0%) than with ESI-beta (24/216, 11.1%; P = 0.012). VAS scores decreased more with ESI-beta than with ESI-dexa at 2 weeks (difference, 0.35; P = 0.023) and 4 weeks (difference, 0.42; P = 0.011). The disability score improved significantly more with ESI-beta compared with ESI-dexa at 2 weeks (difference, 3.37; P = 0.009), 4 weeks (difference, 4.01; P = 0.002), and 8 weeks (difference, 3.54; P = 0.007). @*Conclusions@#Betamethasone would be more appropriate for ESI.

Sporadic Intradural Extramedullary Hemangioblastoma Not Associated with von Hippel-Lindau Syndrome: A Case Report and Literature Review

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 HippelLindau 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.

Sonographic Appearance of Steatocystoma: An Analysis of 14 Pathologically Confirmed Lesions

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.

Sporadic Intradural Extramedullary Hemangioblastoma Not Associated with von Hippel-Lindau Syndrome: A Case Report and Literature Review

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 HippelLindau 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.

Sonographic Appearance of Steatocystoma: An Analysis of 14 Pathologically Confirmed Lesions

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.

Percutaneous Sacroplasty : Effectiveness and Long-Term Outcome Predictors

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.

Spinal Intraosseous Hibernoma: A Case Report and Review of Literature

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.

Various MRI Findings of Toxocara canis Myelitis

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.

Diagnosis of Spinal Metastasis: Usefulness of Additional Diffusion-Weighted Imaging

PURPOSE@#To determine the usefulness of diffusion weighted-MRI (DW-MRI) in the evaluation of spinal metastasis.@*MATERIALS AND METHODS@#From July to August 2017, 48 whole-spine DW-MRI to detect metastasis in patients with extra-spinal tumors were retrospectively evaluated by three radiologists. The usefulness of DW-MRI was evaluated in four groups based on the change in confidence rating between two sessions: 1 (T1- and T2-weighted and contrast-enhanced images) and 2 (additional DW-MRI). The associations of the usefulness with age, sex, primary cancer, bone type with metastasis, number of probable metastatic segments in session 1, and anatomic locations were assessed in vertebral body and posterior element cases.@*RESULTS@#According to the readers 1, 2, and 3, there were 18, 19, and 16 vertebral body cases, respectively, and 12, 13, and 9 posterior element cases, respectively. In the group with no excepted metastasis, DW-MRI was useful in 52–59% of vertebral body cases and 39–67% of posterior element cases. There were no significant differences in the usefulness with respect to the number of probable metastatic segments in session 1, age, sex, primary cancer, bone type with metastasis, or anatomic location.@*CONCLUSION@#DW-MRI could be used to evaluate spinal metastasis. However, there were no differences in the usefulness with respect to the anatomic location.

Systemic effects of fluoroscopically guided epidural steroid injection with dexamethasone / 대한통증학회지

BACKGROUND: Epidural steroid injections (ESIs) have been widely used in managing spinal pain. Dexamethasone has recently emerged as a useful drug in this setting, relative to particulate steroids, although the associated systemic effects have not been fully elucidated. This study aimed to investigate the incidences and types of systemic effects after fluoroscopically guided ESI with dexamethasone. METHODS: This retrospective study included 888 ESIs with dexamethasone (fluoroscopically guided at the cervical and lumbosacral levels) performed on 825 patients during January to June 2017. Data regarding systemic effects were collected via telephone interviews using a standardized questionnaire at 2 weeks after the procedure. Data on patient demographic, clinical, and procedural characteristics were collected and analyzed to identify factors that were associated with systemic effects. All statistical analyses were performed using the chi-squared test. RESULTS: Among the 825 patients, 40 patients (4.8%) experienced systemic effects during the 2-week follow-up period. The most common systemic effect was facial flushing (12 patients, 1.5%), which was followed by urticaria (7 patients, 0.8%) and insomnia (7 patients, 0.8%). A history of spine surgery was significantly associated with the occurrence of systemic effects (P = 0.036). Systemic effects were significantly more common for injections at the cervical level than at the lumbar level (P = 0.019). CONCLUSIONS: Approximately 4.8% of the patients who underwent ESI with dexamethasone experienced minor and transient systemic effects. These effects were more common in patients who had undergone a previous spine surgery or received a cervical ESI.

Do Radiology Residents Perform Well in Preliminary Reporting of Emergency MRIs of Spine?

PURPOSE: To evaluate interpretation errors involving spine MRIs by residents in their second to fourth year of training, classified as minor, intermediate and major discrepancies, as well as the types of commonly discordant lesions with or without clinical significance. MATERIALS AND METHODS: A staff radiologist evaluated both preliminary and final reports of 582 spine MRIs performed in the emergency room from March 2011 to February 2013, involving (1) the incidence of report discrepancy, classified as minor if there was sufficient description of the main MR findings without ancillary or incidental lesions not influencing the main diagnosis, treatment, or patients' clinical course; intermediate if the correct diagnosis was made with insufficient or inadequate explanation, potentially influencing treatment or clinical course; and major if the discrepancy affected the main diagnosis; and (2) the common causes of discrepancy. We analyzed the differences in the incidence of discrepancy with respect to the training years of residents, age and sex of patients. RESULTS: Interpretation discrepancy occurred in 229 of the 582 cases (229/582, 39.3%), including 146 minor (146/582, 25.1%), 40 intermediate (40/582, 6.9%), and 43 major cases (43/582, 7.4%). The common causes of major discrepancy were: over-diagnosis of fracture (n = 10), missed cord lesion (n = 9), missed signal abnormalities associated with diffuse marrow (n = 5), and failure to provide differential diagnosis of focal abnormal marrow signal intensity (n = 5). No significant difference was found in the incidence of minor, intermediate, and major discrepancies according to the levels of residency, patients' age or sex. CONCLUSION: A 7.4% rate of major discrepancies was found in preliminary reporting of emergency MRIs of spine interpreted by radiology residents, probably related to a relative lack of clinical experience, indicating the need for additional training, especially involving spine trauma, spinal cord and bone marrow lesions.

Effect of Poly(Lactide-Co-Glycolide) Nanoparticles on Local Retention of Fluorescent Material: An Experimental Study in Mice

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.

The Efficacy of a Fluoroscopy Guided Epidural Autologous Blood Patch In the Treatment of a Post-Dural Puncture Headache

PURPOSE@#To evaluate the efficacy of a fluoroscopy-guided epidural blood patch (EBP) in the treatment of a post-dural puncture headache (PDPH).@*MATERIALS AND METHODS@#From November 2013 to April 2017, a total of 164 patients (76 males, 88 females, mean age 40.7 years, age range 12 to 87 years) underwent a fluoroscopy guided EBP for the treatment of PDPH in the department of radiology. The treatment outcomes were classified as follows: complete relief, incomplete relief, failure, and recurrence. In the case of recurrence, the duration between the date of the first EBP and the date of recurrence was described. The effectiveness of the second EBP was also evaluated.@*RESULTS@#In 164 PDPH patients, complete relief was achieved in 157 patients (95.8%), incomplete relief was achieved in 1 patient (0.6%), failure in 2 patients (1.2%) and recurrence in 4 patients after the first EBP. All 4 recurrence patients and the 2 failure patients were discharged with complete relief after receiving one additional EBP.@*CONCLUSION@#In patients with PDPH, a fluoroscopy-guided EBP is an effective treatment. Moreover, an additional EBP can be considered in the clinical failure or recurrence of PDPH after the first EBP.

A Comprehensive Review of Shoulder CT Morphometry: What Surgeons Wants to Know

A variety of surgical techniques have been employed for shoulder problems, i.e., arthroplasty, arthroscopy, and fracture fixation, etc. A thorough understanding and knowledge of the normal anatomy, physiology, biomechanics, and pathomechanics of the glenohumeral joint can help facilitate a successful pre-operative evaluation of the shoulder. The authors reviewed practical measurement methods of a shoulder computed tomography (CT) with three-dimensional volume-rendered images, from the orthopedic surgeon's viewpoint, to aid radiologists make structured reports. It is important that the radiologist be familiar with the normal and abnormal imaging appearances of the shoulder CT before and after the surgical procedures.

The Incidence of Various Types of Systemic Reactions Related to Epidural Steroid Injections: A Prospective Observational Study

OBJECTIVE: To evaluate the incidence, types and association of systemic reactions after an epidural steroid injection (ESI) with patient demographics, ESI factors and repeated occurrence of an ESI. MATERIALS AND METHODS: This prospective observational study was approved by the Institutional Review Board of our hospital, and written informed consent was obtained from all the participants. From October to December 2011, systemic reactions at 2 weeks after 960 ESIs among 885 patients were measured. Patients were evaluated by phone interviews to obtain the patients' demographics, history of previous ESI, ESI factors, and ESI reoccurrence. Statistical analyses were performed using the chi-square tests, Fisher's exact tests and a binary logistic regression analysis. RESULTS: Overall, 557 types of systemic reactions occurred after 292 injections (30.4%) of a total of 960 ESIs in which facial flushing was most common (131/557, 23.5%) and 144 ESIs were followed by a mixed form of systemic reactions (49.3%). Age of 62 years or younger (odds ratio [OR], 2.361), female sex (OR, 1.674), and history of diabetes mellitus (OR, 1.681) were significant risk factors in the occurrence of systemic reactions after an ESI. In 73 patients with repeated ESI, 14 patients re-experienced systemic reactions (19.2%), of which twelve re-experienced the same systemic reaction as the previous one. CONCLUSION: Systemic reactions followed about 30% of ESIs, and more commonly occurred in patients 62 years of age or younger, women, and diabetic patients. Half of the patients experienced a mixed form of systemic reactions. Patients with recurring systemic reactions tend to re-experience the same systemic reaction as the prior one after an ESI.

Evaluation of the Subscapularis Tendon Tears on 3T Magnetic Resonance Arthrography: Comparison of Diagnostic Performance of T1-Weighted Spectral Presaturation with Inversion-Recovery and T2-Weighted Turbo Spin-Echo Sequences

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.

Texture Analysis of Torn Rotator Cuff on Preoperative Magnetic Resonance Arthrography as a Predictor of Postoperative Tendon Status

OBJECTIVE: To evaluate texture data of the torn supraspinatus tendon (SST) on preoperative T2-weighted magnetic resonance arthrography (MRA) using the gray-level co-occurrence matrix (GLCM) for prediction of post-operative tendon state. MATERIALS AND METHODS: Fifty patients who underwent arthroscopic rotator cuff repair for full-thickness tears of the SST were included in this retrospective study. Based on 1-year follow-up, magnetic resonance imaging showed that 30 patients had intact SSTs, and 20 had rotator cuff retears. Using GLCM, two radiologists measured independantly the highest signal intensity area of the distal end of the torn SST on preoperative T2-weighted MRA, which were compared between two groups.The relationships with other well-known prognostic factors, including age, tear size (anteroposterior dimension), retraction size (mediolateral tear length), grade of fatty degeneration of the SST and infraspinatus tendon, and arthroscopic fixation technique (single or double row), also were evaluated. RESULTS: Of all the GLCM features, the retear group showed significantly higher entropy (p < 0.001 and p = 0.001), variance (p = 0.030 and 0.011), and contrast (p = 0.033 and 0.012), but lower angular second moment (p < 0.001 and p = 0.002) and inverse difference moment (p = 0.027 and 0.027), as well as larger tear size (p = 0.001) and retraction size (p = 0.002) than the intact group. Retraction size (odds ratio [OR] = 3.053) and entropy (OR = 17.095) were significant predictors. CONCLUSION: Texture analysis of torn SSTs on preoperative T2-weighted MRA using the GLCM may be helpful to predict postoperative tendon state after rotator cuff repair.

Intra-Articular Injections in Patients with Femoroacetabular Impingement: a Prospective, Randomized, Double-blind, Cross-over Study

We evaluated and compared the effectiveness of intra-articular injection of hip joint using hyaluronic acid and steroid in patients with femoroacetabular impingement (FAI). Thirty patients with FAI clinically and radiologically were enrolled and underwent hip injection using steroid (TA) or hyaluronic acid (HA) at 0-weeks with cross-over injection at 2-weeks in patients without clinical response of decrease of pain intensity less than 2-point. Patients were followed up to 12-weeks for pain intensity (Numeric rating scale, NRS: 0-10), hip disability score (HOOS), oral medication and adverse events. In 17 patients without cross-over, HOOS at 2-weeks was improved significantly in patients with HA injection (mean increase of HOOS = 13.8 with HA vs. -2.2 with TA, P = 0.031) without difference of NRS (P = 0.943). In 13 patients with cross-over, NRS was significantly improved at 2-weeks with first TA injection (mean decrease of NRS= 1.7 with first TA vs. 0.3 with first HA, P = 0.036), without difference of HOOS (P = 0.431). At 4-weeks, NRS and HOOS were significantly different according to injection drugs (NRS: 0.9 with TA first and HA later vs. 2.7 with HA first and TA later, P = 0.001; mean increase of HOOS: 5.3 with TA first and HA later vs. 10.2 with HA first and TA later, P = 0.032). Intra-articular hip injection may be effective in FAI, with faster effect of pain improvement by TA and more delayed effect of function improvement by HA.

Quantitative Analysis of Disc Degeneration Using Axial T2 Mapping in a Percutaneous Annular Puncture Model in Rabbits

OBJECTIVE: To evaluate T2 relaxation time change using axial T2 mapping in a rabbit degenerated disc model and determine the most correlated variable with histologic score among T2 relaxation time, disc height index, and Pfirrmann grade. MATERIALS AND METHODS: Degenerated disc model was made in 4 lumbar discs of 11 rabbits (n = 44) by percutaneous annular puncture with various severities of an injury. Lumbar spine lateral radiograph, MR T2 sagittal scan and MR axial T2 mapping were obtained at baseline and 2 weeks and 4 weeks after the injury in 7 rabbits and at baseline and 2 weeks, 4 weeks, and 6 weeks after the injury in 4 rabbits. Generalized estimating equations were used for a longitudinal analysis of changes in T2 relaxation time in degenerated disc model. T2 relaxation time, disc height index and Pfirrmann grade were correlated with the histologic scoring of disc degeneration using Spearman's rho test. RESULTS: There was a significant difference in T2 relaxation time between uninjured and injured discs after annular puncture. Progressive decrease in T2 relaxation time was observed in injured discs throughout the study period. Lower T2 relaxation time was observed in the more severely injured discs. T2 relaxation time showed the strongest inverse correlation with the histologic score among the variables investigated (r = -0.811, p < 0.001). CONCLUSION: T2 relaxation time measured with axial T2 mapping in degenerated discs is a potential method to assess disc degeneration.

Factors Affecting Radiation Exposure during Lumbar Epidural Steroid Injection: A Prospective Study in 759 Patients

OBJECTIVE: To estimate and compare radiation exposure and intervention time during lumbar epidural steroid injection (ESI) 1) under different practitioners and methods with continuous fluoroscopic monitoring, and 2) under one practitioner with different methods and monitoring. MATERIALS AND METHODS: We consecutively recruited 804 patients who underwent lumbar ESI and 759 patients who underwent 922 interventions were included for analysis in this investigation. Three different practitioners (a senior faculty member, junior faculty member, trainee) performed lumbar ESI using different methods (caudal, interlaminar, transforaminal). The senior faculty member performed lumbar ESI under two different methods of fluoroscopic monitoring (continuous [CM] and intermittent monitoring [IM]). The dose area product (DAP) fluoroscopy time, and intervention time during lumbar ESI were compared for 1) ESI methods and practitioners under CM, and 2) ESI methods and monitoring. RESULTS: With CM, interaction between the effects of the practitioner and the intervention on DAP was significant (p < 0.001), but not fluoroscopy time (p = 0.672) or intervention time (p = 0.852). The significant main effects included the practitioner and intervention on DAP, fluoroscopy time, and intervention time with CM (p < 0.001). DAPs and fluoroscopy time for caudal, interlaminar, and transforaminal ESI were higher with CM than with IM (p < 0.001). Intervention time did not differ between CM and IM. CONCLUSION: Radiation exposure is dependent on the practitioners and methods and within the established safety limits during lumbar ESIs under CM. With an experienced practitioner, IM leads to less radiation exposure than CM.