Piriformis syndrome: muscle thickness or volume does not correlate with response to CT-guided injection.

OBJECTIVE: To determine whether size of the piriformis muscle, as characterized by either the coronal width or a segmented volume, correlates with outcomes after CT-guided injections. MATERIALS AND METHODS: A consecutive series of 81 patients with piriformis syndrome received CT-guided injections of the sciatic nerve and piriformis muscle. Volume and thickness measurements of the piriformis were taken from T1W and T2W pre-injection images by two readers. A logistic regression was used to test volume and size effect on first injection response. A cox proportional hazards model was used to evaluate pain-free survival. Identical analyses were performed to test the effects of muscle mass abnormality, nerve abnormality, body mass index, and presence of a split sciatic nerve. RESULTS: There were 15/94 negative responses, 31/94 possible positive responses, and 48/94 positive responses to CT-guided injection. The average pain-free survival time was 38.91 ± 64.43 days. There was no significant correlation of first injection responses with muscle thickness or volume. There was no significant correlation in pain-free survival for muscle thickness or volume. There was no significant correlation in first injection response or pain-free survival with body mass index, muscle abnormalities, nerve abnormalities, or split sciatic nerves. The intraclass correlation was excellent between the two readers for both muscle volume (0.95-0.98) and thickness (0.92-0.97). CONCLUSION: Piriformis muscle volume or thickness did not significantly correlate with post-injection outcome (first injection response and pain-free survival). Thus, if the patient has clinical symptoms of piriformis syndrome, the size of muscle should not determine whether injection is advisable.

Three-dimensional and 3-Tesla MRI morphometry of knee meniscus in normal and pathologic state.

INTRODUCTION: To conduct a morphometric analysis of intact and torn menisci using isotropic meniscus plane three-dimensional (3D) reconstructions on 3-Tesla MRI and compare 2D versus 3D MRI for meniscus tear characterization. MATERIALS AND METHODS: One hundred thirty three normal menisci from 92 patients (39 male, 53 female), and 38 arthroscopy-proven torn menisci from 36 patients (23 male, 13 female) were evaluated using 3D isotropic multi-planar MRI reconstructions and 2D MRI. Two observers measured the tibial plateau height and area, meniscal height, axial plane cross-sectional areas, and extrusion of intact menisci. Two observers also measured the meniscal tear length, tear area, and residual area of pathological menisci on 2D and 3D MRI. Intraclass correlation coefficients (ICC) were obtained. Institutional Review Board approval was obtained, and the informed consent was waived. RESULTS: Medial meniscus (MM) and lateral meniscus (LM) areas were 503.6 ± 85.1 mm2 and 396.6 ± 72.0 mm2 for Observer 1, and 515.8 ± 82.1 mm2 and 408.0 ± 68.3 mm2 for Observer 2 (ICC:0.86, 0.87). In torn menisci, average tear length, area, and residual area were 36.3 ± 13.6 mm, 182.6 ± 139.3 mm2 , and 235.4 ± 140.3 mm2 , respectively for Observer 1, and 38.9 ± 14.7 mm, 181.2 ± 135.6 mm2 , 238.2 ± 140.5 mm2 for Observer 2. In the MM and LM, bucket-handle and complex tears were largest in areas, respectively. ICCs were excellent (0.91-1.0) on 3D MRI and moderate-good (0.57-0.81) on 2D MRI. CONCLUSION: Meniscus morphometry on 3D MRI shows moderate to excellent inter-observer reliability and meniscus tear extent is more reliably defined on 3D MRI than 2D MRI. Residual meniscus-area calculation can be performed on 3D MRI.

Quantitative assessment of diabetic amyotrophy using magnetic resonance neurography-a case-control analysis.

OBJECTIVES: To quantitatively characterize diabetic amyotrophy (DA), or diabetic lumbosacral radiculoplexopathy, and compare with controls using magnetic resonance neurography (MRN). METHODS: Forty controls and 23 DA cases were analyzed qualitatively and quantitatively. Cross-sectional areas (CSAs) of bilateral L3 through S2 lumbosacral nerve roots, femoral nerves, and sciatic nerves (proximal and distal measurements) were measured. A linear model was used to assess the nerve location and case/control effect on angle-corrected CSAs. Intra- and inter-reader analysis was performed using intraclass correlation (ICC). RESULTS: In DA cases, abnormalities of the lumbosacral nerve roots, sciatic, femoral, and obturator nerves were seen in 21/23, 16/23, 21/23, and 9/23, respectively. Denervation abnormalities of multiple abdominopelvic muscles were seen. Quantitatively, the CSA of all measured LS plexus nerve roots and bilateral femoral nerves were significantly larger in DA cases vs. controls by 45% (95% CI, (30%, 49%); p < 0.001). The ICC was moderate for inter-rater analysis = 0.547 (95% CI, 0.456-0.626) and excellent for intra-rater analysis = 0.90 (95% CI, 0.89-92). CONCLUSIONS: Multifocal neuromuscular lesions related to diabetic amyotrophy were qualitatively and quantitatively detected on MRN. Qualitative abnormalities distinguished cases from controls, and nerve CSAs of cases were significantly larger than those of controls. Therefore, MRN may be employed as a non-invasive diagnostic tool for the evaluation of diabetic amyotrophy. KEY POINTS: • Qualitative abnormalities of lumbosacral nerve roots, their peripheral branches, and muscles are seen in DA. • The lumbosacral nerve roots and their peripheral branches in diabetic amyotrophy cases are significantly larger in cross-sectional area than non-diabetic subjects by 45% (95 CI, 30%, 49%; p < 0.001). • The ICC was moderate for inter-rater analysis = 0.547 (95% CI, 0.456-0.626) and excellent for intra-rater analysis = 0.90 (95% CI, 0.89-92).

The International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine classification of knee meniscus tears: three-dimensional MRI and arthroscopy correlation.

OBJECTIVES: To introduce MRI-based International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification system of meniscal tears and correlate it to the surgical findings from arthroscopy. We hypothesized that the ISAKOS classification will provide good inter-modality and inter-rater reliability for use in the routine clinical practice of radiologists and orthopedic surgeons. METHODS: In this HIPAA-compliant cross-sectional study, there were 44 meniscus tears in 39 patients (26 males, 16 females). Consecutive arthroscopy-proven meniscal tears (March 2017 to December 2017) were evaluated by two board-certified musculoskeletal radiologists using isotropic three-dimensional (3D) MRI user-defined reconstructions. The surgically validated ISAKOS classification of meniscal tears was used to describe medial meniscus (MM) and lateral meniscus (LM) tears. Prevalence-adjusted bias-adjusted kappa (PABAK) and conventional kappa, and paired t test and intra-class correlation coefficient (ICC) were calculated for categorical and numerical variables, respectively. RESULTS: For the MM, the PABAK for location, depth, length (ICC), pattern, quality of meniscus tissue, and zone was 0.7-1, 0.65, 0.57, 0.67, 0.78, and 0.39-0.7, respectively. For the LM, the PABAK for location, depth, length (ICC), pattern, quality of meniscus tissue, zone, and central to popliteus hiatus was 0.57-0.95, 0.57, 0.74, 0.93, 0.38, 0.52-0.67, and 0.48, respectively. The mean tear lengths were larger on MRI than on arthroscopy (mean difference MM 9.74 mm (6.66 mm, 12.81 mm; p < 0.001), mean difference LM 4.04 mm (0.31 mm, 7.76 mm; p = 0.034)). CONCLUSIONS: The ISAKOS classification of meniscal tears on 3D MRI provides mostly moderate agreement, which was similar to the agreement at arthroscopy. KEY POINTS: • There is a fair to good inter-method correlation in most categories of ISAKOS meniscus tear classification. • The tear lengths are significantly larger on MRI than on arthroscopy. • The inter-reader correlation on 3D MRI is moderate to excellent, with the exception of lateral meniscus tear patterns.

Role of MR Neurography in Groin and Genital Pain: Ilioinguinal, Iliohypogastric, and Genitofemoral Neuralgia.

OBJECTIVE: Chronic neuralgia of the border nerves (ilioinguinal, iliohypogastric, and genitofemoral) is difficult to diagnose and treat clinically. We examined the role of MR neurography (MRN) in the evaluation of border nerve abnormalities and the results of treatments directed at the MRN-detected nerve abnormalities. MATERIALS AND METHODS: This retrospective cross-sectional study included 106 subjects with groin or genital pain (mean [± SD] age, 50.7 ± 15.4 years) who showed mono- or multifocal neuropathy of the border nerves at 3-T MRN. Subjects who underwent CT-guided perineural injection were assessed for pain response. Injection responses were categorized as positive, possible positive, and negative. Subjects who received hyaluronidase, continuous radiofrequency ablation, or surgery were also evaluated for treatment outcomes. RESULTS: One hundred forty abnormal nerves were positive for neuropathy in 106 studies. Eighty of 106 subjects had single neuropathy, and 26 had multifocal neuropathy. Fifty-eight subjects underwent CT-guided perineural injections, with five receiving bilateral injections (63 injections). Improvement in subjective pain was seen in 53 of 63 cases (84.2%). A statistically significant improvement in pain response was noted in the isolated ilioinguinal nerve block group as compared with the isolated genitofemoral nerve block group (p = 0.0085). Thirteen of 58 subjects received multiple nerve injections at the same sitting. Both groups receiving single or multiple nerve injections had similar improvement in pain scores of 84% and 85%, respectively, although this difference was not statistically significant. CONCLUSION: Our retrospective analysis showed improved pain relief in subjects who underwent CT-guided nerve blocks on the basis of a positive MRN.

Diffusion tensor imaging of diabetic amyotrophy.

OBJECTIVE: To qualitatively and quantitatively characterize the nerves of patients with diabetic amyotrophy (DA) using magnetic resonance neurography (MRN) with diffusion tensor imaging (DTI). MATERIALS AND METHODS: Forty controls and 13 DA cases were analyzed. 1.5-Tesla and 3.0-Tesla MRN with DTI was used. Qualitative data from 13 patient records were recorded. Region of interest (ROI) measurements were taken of bilateral L3 through S2 lumbosacral nerve roots, femoral nerves, and sciatic nerves. An ANOVA and multiple linear regression analysis were performed. An intraclass correlation coefficient (ICC) was calculated between two readers. RESULTS: In DA cases, abnormalities of the lumbosacral nerve roots (n = 11 patients), sciatic (n = 10), femoral (n = 13), and obturator nerves (n = 4) were seen; denervation changes of the abdominopelvic muscles were also identified. Quantitatively, minimum and mean nerve signals on B600 were significantly less than controls (p < 0.001). Minimum and mean ADC values were significantly greater in cases than in controls (p < 0.001 and p = 0.002 respectively). Mean fractional anisotropy (FA) values were significantly lower in cases than in controls (p = 0.041). There were no significant differences in the minimum FA values between cases and controls. Minimum and mean ADCs correlated positively with highest recorded hemoglobin A1 (HbA1c) while controlling for sex, age, and BMI (ß = 0.518, p < 0.001 and ß = 0.302, p = 0.020 respectively). ICCs were 0.892 (B600), 0.717 (ADC), and 0.730 (FA). CONCLUSION: Neuromuscular lesions secondary to DA are qualitatively and quantitatively identified on MRN with DTI, and a positive correlation of ADC levels with serum HbA1c levels exists. Thus, MRN with DTI can be employed as a non-invasive diagnostic tool, if DA is suspected.

Piriformis syndrome: pain response outcomes following CT-guided injection and incremental value of botulinum toxin injection.

PURPOSE: Piriformis syndrome is a common pain condition affecting the buttock and posterior hip with or without radiation to the leg, and management of the condition involves many treatments. In this study, we hypothesize that a CT-guided injection with botulinum toxin is more effective in providing pain relief than a CT-guided injection without Botox. METHODS: Overall, 97 consecutive patients with piriformis syndrome presented for a CT-guided injection of the piriformis muscle and perineural injection of the sciatic nerve. After the injection, the patients received a visual analog scale pain log to record their pain level until the follow-up appointment. P values of less than 0.2 were considered as confounder and adjusted by inverse probability of treatment weighting (IPTW) via propensity score. The effect of botulinum toxin on 48-hour response and duration of response was tested using weighted chi-square test and weighted Kaplan-Meier analysis. RESULTS: There was a total of 97 patients in the study, and 111 injections, as some patients had bilateral injections. Patients in the Botox group had more 48-hour response than patients in the non-botulinum toxin group (P < 0.001 with IPTW, P = 0.005 without IPTW). Median pain-free survival was 30 days for Botox group and 1 day for non-Botox group (P = 0.059 with IPTW, P = 0.10 without IPTW). CONCLUSION: CT-guided injections with botulinum toxin for patients with piriformis syndrome are more likely to lead to a positive response and a longer duration of response than patients who receive a CT-guided injection without botulinum toxin. We hope that this study facilitates future prospective randomized blind trials for patients with suspected piriformis syndrome.

Upper limb peripheral neuropathy in sickle cell anemia: MR neurography appearances.

Sickle cell anemia is an inherited disorder with many systemic complications. Peripheral neuropathy related to this disorder has been sparsely reported. We report an interesting case of upper limb peripheral neuropathy from sickle cell disease with emphasis on MR neurography appearances and electrophysiology correlation.

Association Between Bone Mineral Density and Depressive Symptoms in a Population-Based Sample.

OBJECTIVE: This analysis was conducted to determine the relationship between bone mineral density (BMD) and depressive symptoms in a population-based cohort. METHODS: Data were extracted from the second phase of the Dallas Heart Study (DHS-2), a large, multiethnic population sample in Dallas County, Texas, from September 1, 2007, to December 31, 2009. Depressive symptom severity was measured with the 16-item Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR16), which is derived from DSM-IV major depressive disorder criteria. BMD was measured using dual-energy x-ray absorptiometry. Multiple linear regressions examined the relationship between QIDS-SR16 score and BMD controlling for age, body mass index, sex, ethnicity, smoking status, alcohol use status, serum 25-hydroxyvitamin D concentration, antidepressant use, and physical activity as measured by total vigorous and moderate metabolic equivalents. Subgroup analyses explored differences related to age. RESULTS: QIDS-SR16 score was not a significant predictor of either lumbar spine or total hip T-score (ß = -0.01, P = .61 and ß = -0.02, P = .39) in the overall population (n = 2,285). There was a significant negative interaction term between age and QIDS-SR16 group (ß = -0.01, P = .01). In participants aged 60 years or older (n = 465), QIDS-SR16 score was a significant predictor of BMD at the lumbar spine and total hip (ß = -0.14, P = .003 and ß = -0.12, P = .006, respectively). CONCLUSIONS: QIDS-SR16 score did not significantly predict BMD in the overall DHS-2 sample. There was, however, a significant association observed in participants aged ≥ 60 years. Results suggest that diagnosis and treatment of depressive symptoms may be of clinical importance in older individuals, a subgroup at high risk for osteoporosis and fractures.

Progress Report on the Generation of Polyfunctional Microscale Particles for Programmed Self-Assembly.

A process for 3D programmed self-assembly of lithographically printable microscale polymer particles using ssDNA hybridization as the associative force is described. We report our progress in establishing the unit processes required for 3D programmed self-assembly and demonstrate the successful fabrication and sequence-specific self-assembly of covalent ssDNA-functionalized parallelepipeds with dimensions in the sub 10 µm regime characterized by optical microscopy and imaging flow cytometry. This technology has the potential to produce parallelepiped particles with different ssDNA on each facet.