Risto Ojala

Modic changes in endplates of lumbar vertebral bodies: prevalence and association with low back and sciatic pain among middle-aged male workers.

Study Design. Cross-sectional comparison of self-reported low back pain (LBP) symptoms and Modic findings on magnetic resonance imaging (MRI). Objectives. To investigate associations of frequency and intensity of LBP and sciatic pain with Modic changes in a sample of middle-aged male workers with or without whole-body vibration exposure. Summary of Background Data. Vertebral endplate changes are bone marrow lesions visible on MRI and are assumed to be associated with degenerative intervertebral disc disease. Associations of these so-called Modic changes with clinical symptoms are controversial. Furthermore, most of these studies have been performed in selected series of patients. Methods. A total of 228 middle-aged male workers (159 train engineers and 69 sedentary controls) from northern Finland underwent sagittal T1 and T2-weighted MRI. Both endplates of 1140 lumbar interspaces were graded for type and extent of Modic changes. Logistic regression was used to analyze associations of pain variables with Modic changes. Results. Train engineers had on the average higher sciatic pain scores than the sedentary controls, but the prevalence of Modic changes was similar in both occupational groups. Altogether, 178 Modic changes in 128 subjects were recorded: 30% were type I, 66% type II, and 4% both types I and II. Eighty percent of changes occurred at L4–L5 or L5–S1. Modic changes at L5–S1 showed significant association with pain symptoms with increased frequency of LBP (odds ratio [OR] 2.28; 95% confidence interval [CI] 1.44–3.15) and sciatica episodes (OR 1.44; 95% CI 1.01–1.89), and with higher LBP visual analog scores during the past week (OR 1.36; 95% CI 1.06–1.70). Type I lesions and extensive lesions in particular were closely associated with pain. Conclusions. Modic changes at L5–S1 and Modic type I lesions are more likely to be associated with pain symptoms than other types of Modic changes or changes located at other lumbar levels.

Determinants of spontaneous resorption of intervertebral disc herniations

Study Design. A follow-up of disc herniation (herniated nucleus pulposus [HNP]) resorption on magnetic resonance imaging (MRI). Objective. To assess the determinants of resorption of HNP. Summary of Background Data. Neovascularization in the outermost areas of HNP, presenting as an enhancing rim in gadolinium diethylenetriamine pentaacetic acid MR images, is thought to be a major determinant of spontaneous resorption of HNP. Methods. Patients with HNP-induced sciatica at baseline were rescanned at 2 months (N = 74) and after 12 months (N = 53). The volume of HNP (mm3), thickness (mm) and extent (%) of enhancement, and the degree of HNP migration (Komori classification) were analyzed. Repeated measures analysis of covariance was used in statistical analysis. Results. Significant resorption of HNP occurred from baseline to 2 months, although the resorption rate was more pronounced over the whole 1-year follow-up. Higher baseline scores of rim enhancement thickness, higher degree of HNP displacement in the Komori classification, and age category 41–50 years were associated with a higher resorption rate. Thickness of rim enhancement was a stronger determinant of spontaneous resorption than extent of rim enhancement. Clinical symptom alleviation occurs concordantly with a faster resorption rate. Conclusions. MRI is a useful prognostic tool for identifying patients with HNP-induced sciatica with a benign natural course.

Reproducibility of imaging human knee cartilage by delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at 1.5 Tesla

OBJECTIVE The purpose of this study was to investigate the day-to-day reproducibility of the delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) measurement at different knee joint surfaces in healthy subjects at 1.5 Tesla (T). METHODS The dGEMRIC experiment was repeated for 10 asymptomatic volunteers three times with an average interval of 5 days between scans. The measurement was performed from a single sagittal slice through the center of the lateral femoral condyle and from the center of the patella in the axial plane. Cartilage was manually segmented into superficial, deep and full-thickness regions of interests (ROIs) at different topographical locations of the femur, tibia and patella. The reproducibility was evaluated separately for each ROI as well as for the entire bulk cartilage in the slice of each joint surface. RESULTS The reproducibility at various ROIs expressed by root-mean-square average coefficient of variation (CV(RMS)) ranged between 4.7-12.9%. Thirty out of thirty-three ROIs showed a CV(RMS) less than 10%. Intraclass correlation coefficient (ICC) ranged between 0.45 and 0.98. The CV(RMS) and ICC for bulk dGEMRIC were 4.2% and 0.95 for femur, 5.5% and 0.87 for tibia, and 4.8% and 0.97 for patella. CONCLUSIONS The dGEMRIC technique showed good day-to-day reproducibility, on the average 8% for small deep or superficial segments, 7% for full-thickness ROIs and 5% for bulk ROIs covering all visible cartilage in a single joint surface. We conclude that dGEMRIC imaging at field strength 1.5 T can be used as a reliable instrument for the assessment of articular cartilage when staff has been carefully trained.

Are the determinants of vertebral endplate changes and severe disc degeneration in the lumbar spine the same? A magnetic resonance imaging study in middle-aged male workers

BackgroundModic changes are bone marrow lesions visible in magnetic resonance imaging (MRI), and they are assumed to be associated with symptomatic intervertebral disc disease, especially changes located at L5-S1. Only limited information exists about the determinants of Modic changes. The objective of this study was to evaluate the determinants of vertebral endplate (Modic) changes, and whether they are similar for Modic changes and severe disc degeneration focusing on L5-S1 level.Methods228 middle-aged male workers (159 train engineers and 69 sedentary factory workers) from northern Finland underwent sagittal T1- and T2-weighted MRI. Modic changes and disc degeneration were analyzed from the scans. The participants responded to a questionnaire including items of occupational history and lifestyle factors. Logistic regression analysis was used to evaluate the associations between selected determinants (age, lifetime exercise, weight-related factors, fat percentage, smoking, alcohol use, lifetime whole-body vibration) and Modic type I and II changes, and severe disc degeneration (= grade V on Pfirrmanns classification).ResultsThe prevalences of the Modic changes and severe disc degeneration were similar in the occupational groups. Age was significantly associated with all degenerative changes. In the age-adjusted analyses, only weight-related determinants (BMI, waist circumference) were associated with type II changes. Exposure to whole-body vibration, besides age, was the only significant determinant for severe disc degeneration. In the multivariate model, BMI was associated with type II changes at L5-S1 (OR 2.75 per one SD = 3 unit increment in BMI), and vibration exposure with severe disc degeneration at L5-S1 (OR 1.08 per one SD = 11-year increment in vibration exposure).ConclusionBesides age, weight-related factors seem important in the pathogenesis of Modic changes, whereas whole-body vibration was the only significant determinant of severe disc degeneration.

MRI-guided trephine biopsy and fine-needle aspiration in the diagnosis of bone lesions in low-field (0.23 T) MRI system using optical instrument tracking

Abstract. The purpose of this study was to evaluate the feasibility of MRI-guided bone biopsy with optical instrument tracking and evaluate advantage of combined fine-needle aspiration (FNA) with trephine biopsy. Twenty trephine bone biopsies and 13 FNAs were performed under MRI and CT guidance in 14 patients. Informed consent was obtained from all patients. The evaluation of diagnostic accuracy was achieved by comparing the histopathological and cytological diagnosis with current or final diagnosis made during 6-month clinical follow-up. A 0.23-T open MRI scanner with interventional tools (Outlook Proview, Marconi Medical Systems, Cleveland, Ohio) was used. A surface coil was used. For trephine biopsy MRI-compatible bone biopsy set (Daum medical, Schwerin, Germany) was used. The FNA was performed with MRI compatible 20-G needle (Cook, Bloomington, Ind.). The diagnostic accuracy of MRI-guided trephine biopsy was 95%. The FNA sample diagnosis concurred with the histological in 54%. Our results show that MRI guidance in bone biopsies is accurate and safe. It is comparable to CT-guided or open biopsy. The role of combined FNA with bone biopsies remains controversial.

Nerve Root Infiltration of the First Sacral Root With MRI Guidance

The purpose of this clinical trial was to describe the methodology and evaluate the accuracy of optical tracking‐based magnetic resonance (MR)‐guided infiltration of the first sacral (S1) root. Thirty‐five infiltrations were performed on 34 patients with a 0.23‐T open C‐arm magnet installed in a fully equipped operation room with large‐screen (36 inches) display and optical navigator utilizing infrared passive tracking. T1 and T2 fast spin‐echo (FSE) images were used for localizing the target and fast field echo for monitoring the procedure. Saline as contrast agent in single‐shot (SS)FSE images gave sufficient contrast‐to‐noise ratio. Twenty‐four patients had unoperated L5/S1 disc herniation, and 10 had S1 root irritation after failed back surgery. Needle placement was successful in 97% of the cases, and no complications occurred. Outcome was evaluated 1–6 months (mean 2.2 months) after the procedure and was comparable to that of other studies using fluoroscopy or computed tomography guidance. MR‐guided placement of the needle is an accurate technique for first sacral root infiltration. J. Magn. Reson. Imaging 2000;12:556–561.

Topographical variation of T2 relaxation time in the young adult knee cartilage at 1.5 T

OBJECTIVE To assess the normal topographical variation of T2 relaxation time of articular cartilage in different compartments of the knee joint and at different tissue depths in young healthy adults. METHODS Twenty asymptomatic young adult volunteers (age range, 21-27 years; mean age, 22.5 years), were studied at 1.5T. Both axial and sagittal multi-slice multi-echo spin echo measurements were performed to determine the T2 relaxation time of cartilage in the femoral, tibial and patellar compartments. The cartilage surfaces were divided into 24 segments and each segment was divided into deep and superficial regions-of-interest (ROIs) of equal thickness. The reproducibility for ROI analysis was assessed for five patients by determining the interclass correlation coefficient (ICC) and the root-mean-square coefficient of variation (CV(RMS)). RESULTS Cartilage T2 was significantly dependent on joint topography, compartment and tissue depth. For all joint surfaces, superficial T2 values were systematically higher as compared to deep tissue. The data showed a trend toward higher T2 values at the load bearing area of the femoral condyles. The interobserver error varied significantly among different locations and showed mostly good reproducibility with mean ICC of 0.70 and a CV(RMS) of 5.0%. CONCLUSION The normal variation in cartilage T2 within a joint is significant and should be acknowledged when pathology-related T2 changes are investigated. The knowledge on normal variation can be used for power and sample size calculations in further studies, and the T2 values as control data in future patient studies.

Percutaneous MR‐guided discography in a low‐field system using optical instrument tracking: A feasibility study

To evaluate the feasibility of MRI‐guided discography with optical tracking.

MR-guided bone biopsy: Preliminary report of a new guiding method

To evaluate the feasibility of a new MR compatible optical tracking guided bone biopsy system.

Preoperative radiological factors correlated to long-term recurrence of hallux valgus following distal chevron osteotomy.

Background: The purpose of this article was to analyze the long-term radiologic results after distal chevron osteotomy for hallux valgus treatment and to determine the preoperative radiographic factors correlating with radiological recurrence of the deformity. Methods: The study included 100 consecutive patients who received distal chevron osteotomy for hallux valgus. The osteotomy included fixation with an absorbable pin in 50 cases, and no fixation in the other 50. For 6 weeks postoperatively, half of each group used a soft cast and half had a traditional elastic bandage. Weight-bearing radiographs were evaluated at 6 weeks, 6 months, 1 year, and a mean of 7.9 (range, 5.8-9.4) years postoperatively. Results: At the final follow-up, radiological recurrence of hallux valgus deformity (HVA > 15 degrees) was observed in 56 feet (73%). Eleven feet (14%) had mild recurrence (HVA < 20 degrees), 44 (57%) moderate (20 degrees ≥ HVA < 40 degrees), and 1 (1%) severe (HVA ≥ 40 degrees). All recurrences were painless, and thus no revision surgery was required. Long-term hallux valgus recurrence was significantly affected by preoperative congruence, DMAA, sesamoid position, HVA, and I/II IMA. Conclusions: Radiological recurrence of hallux valgus deformity of 15 degrees or more was very common at long-term follow-up after distal chevron osteotomy. Preoperative congruence, DMAA, sesamoid position (LaPorta), HVA, and I/II IMA significantly affected recurrence. Level of Evidence: Level III, comparative case series.