Interobserver reliability in the interpretation of diagnostic lumbar MRI and nuclear imaging

Standardized Classification of Lumbar Spine Degeneration on Magnetic Resonance Imaging Reduces Intra- and Inter-subspecialty Variability

BACKGROUND AND PURPOSE

To determine the efficacy of standardized definitions of degenerative change in reducing variability in interpretation of lumbar spine magnetic resonance imaging within and between groups of subspecialty-trained neuroradiologists (NR) and musculoskeletal radiologists (MSK).

MATERIALS AND METHODS

Six radiologists, three from both NR and MSK groups were trained on a standardized classification system of degenerative change. After an 11-month washout period, they independently re-interpreted fifty exams at the L4-L5 and L5-S1 levels. Responses were converted to a six-point ordinal scale for the assessment of neural foraminal stenosis and spinal canal stenosis (SCS), three-point scale for lateral recess stenosis, and four-point scale for facet osteoarthritis (FO). Intra-subspecialty and inter-subspecialty analysis was performed using the weighted Cohen's kappa with a binary matrix of all reader pairs.

RESULTS

Inter-subspecialty agreement improved from k=0.527 (moderate) to k=0.602 (substantial) for neural foraminal stenosis, from k=0.540 (moderate) to k=0.652 (substantial) for SCS, from k=0.0818 (slight) to k=0.337 (fair) for lateral recess stenosis, and from k=0.176 (slight) to k=0.495 (moderate) for FO. The NR group demonstrated improved intra-subspecialty agreement for the assessment of SCS, from k=0.368 (fair) to k=0.638 (substantial). The MSK group demonstrated improved intra-subspecialty agreement for the assessment of FO, from k=0.134 (slight) to k=0.413 (moderate). Intra-subspecialty agreement was similar for other parameters before and after training.

CONCLUSIONS

As result of the standardized definitions training, the NR and MSK groups each improved in one of the four parameters, while inter-subspecialty variability improved in all four parameters. These definitions may be useful in clinical practice across radiology subspecialties.

Simplified Universal Grading of Lumbar Spine MRI Degenerative Findings: Inter-Reader Agreement of Non-Radiologist Spine Experts

OBJECTIVE

1) To describe a simplified multidisciplinary grading system for the most clinically relevant lumbar spine degenerative changes. 2) To measure the inter-reader variability among non-radiologist spine experts in their use of the classification system for interpretation of a consecutive series of lumbar spine magnetic resonance imaging (MRI) examinations.

METHODS

ATS multidisciplinary and collaborative standardized grading of spinal stenosis, foraminal stenosis, lateral recess stenosis, and facet arthropathy was developed. Our institution's picture archiving and communication system was searched for 50 consecutive patients who underwent non-contrast MRI of the lumbar spine for chronic back pain, radiculopathy, or symptoms of spinal stenosis. Three fellowship-trained spine subspecialists from neurosurgery, orthopedic surgery, and physiatry interpreted the 50 exams using the classification at the L4-L5 and L5-S1 levels. Inter-reader agreement was assessed with Cohen's kappa coefficient.

RESULTS

For spinal stenosis, the readers demonstrated substantial agreement (κ = 0.702). For foraminal stenosis and facet arthropathy, the three readers demonstrated moderate agreement (κ = 0.544, and 0.557, respectively). For lateral recess stenosis, there was fair agreement (κ = 0.323).

CONCLUSIONS

A simplified universal grading system of lumbar spine MRI degenerative findings is newly described. Use of this multidisciplinary grading system in the assessment of clinically relevant degenerative changes revealed moderate to substantial agreement among non-radiologist spine physicians. This standardized grading system could serve as a foundation for interdisciplinary communication.

Detecting lumbar lesions in 99m Tc-MDP SPECT by deep learning: Comparison with physicians

PURPOSE

^99m Tc-MDP single-photon emission computed tomography (SPECT) is an established tool for diagnosing lumbar stress, a common cause of low back pain (LBP) in pediatric patients. However, detection of small stress lesions is complicated by the low quality of SPECT, leading to significant interreader variability. The study objectives were to develop an approach based on a deep convolutional neural network (CNN) for detecting lumbar lesions in ^99m Tc-MDP scans and to compare its performance to that of physicians in a localization receiver operating characteristic (LROC) study.

METHODS

Sixty-five lesion-absent (LA) ^99m Tc-MDP studies performed in pediatric patients for evaluating LBP were retrospectively identified. Projections for an artificial focal lesion were acquired separately by imaging a ^99m Tc capillary tube at multiple distances from the collimator. An approach was developed to automatically insert lesions into LA scans to obtain realistic lesion-present (LP) ^99m Tc-MDP images while ensuring knowledge of the ground truth. A deep CNN was trained using 2.5D views extracted in LP and LA ^99m Tc-MDP image sets. During testing, the CNN was applied in a sliding-window fashion to compute a 3D "heatmap" reporting the probability of a lesion being present at each lumbar location. The algorithm was evaluated using cross-validation on a ^99m Tc-MDP test dataset which was also studied by five physicians in a LROC study. LP images in the test set were obtained by incorporating lesions at sites selected by a physician based on clinical likelihood of injury in this population.

RESULTS

The deep learning (DL) system slightly outperformed human observers, achieving an area under the LROC curve (AUC_LROC ) of 0.830 (95% confidence interval [CI]: [0.758, 0.924]) compared with 0.785 (95% CI: [0.738, 0.830]) for physicians. The AUC_LROC for the DL system was higher than that of two readers (difference in AUC_LROC [ΔAUC_LROC ] = 0.049 and 0.053) who participated to the study and slightly lower than that of two other readers (ΔAUC_LROC  = -0.006 and -0.012). Another reader outperformed DL by a more substantial margin (ΔAUC_LROC  = -0.053).

CONCLUSION

The DL system provides comparable or superior performance than physicians in localizing small ^99m Tc-MDP positive lumbar lesions.

Clinical Use of Quantitative Analysis of Bone Scintigraphy to Assess the Involvement of Arthritis Diseases in Patients with Joint Symptoms

We aimed to compare the diagnostic ability of quantitative analysis of bone scintigraphy with that of visual analysis for identifying arthritis disease involvement in patients with joint symptoms. We retrospectively included 93 patients with joint symptoms who underwent Tc-99m methylene diphosphonate bone scintigraphy for evaluating arthritis disease involvement. Bone scintigraphy images were visually and quantitatively analyzed using an in-house software by two reviewers. On quantitative analysis, joint uptake ratio was measured for 64 joints in 14 joints areas. The inter-rater agreement of visual and quantitative analyses was assessed, and diagnostic abilities were compared based on the area under the receiver operating characteristic (ROC) curve (AUC) values. Regarding visual analysis, there was a moderate degree of inter-rater agreement (kappa coefficient of 0.597), while there was a substantial inter-rater agreement (concordance correlation coefficient of 0.987) in the measurement of the joint uptake ratio. The comparisons of ROC curves for the total 5941 joints revealed that the joint uptake ratio had a significantly higher AUC value (0.789) to detect the affected joint than that of the visual analysis (p < 0.001). Quantitative analysis using joint uptake ratio showed substantial reproducibility and higher diagnostic ability to detect joints involving arthritis diseases than visual analysis on bone scintigraphy.

Degenerative findings in lumbar spine MRI: an inter-rater reliability study involving three raters

BACKGROUND

For diagnostic procedures to be clinically useful, they must be reliable. The interpretation of lumbar spine MRI scans is subject to variability and there is a lack of studies where reliability of multiple degenerative pathologies are rated simultaneously. The objective of our study was to determine the inter-rater reliability of three independent raters evaluating degenerative pathologies seen with lumbar spine MRI.

METHODS

Fifty-nine people, 35 patients with low back pain (LBP) or LBP and leg pain and 24 people without LBP or leg pain, received an MRI of the lumbar spine. Three raters (one radiologist and two chiropractors) evaluated the MRIs for the presence and severity of eight degenerative spinal pathologies using a standardized format: Spondylolisthesis, scoliosis, annular fissure, disc degeneration, disc contour, nerve root compromise, spinal stenosis and facet joint degeneration. Findings were identified and classified at disc level according to type and severity. Raters were instructed to evaluate all study sample persons once to assess inter-rater reliability (fully crossed design). Reliability was calculated using Gwet's Agreement Coefficients (AC1 and AC2) and Cohen's Kappa (κ) and Conger's extension of Cohen's. Gwet's probabilistic benchmarking method to the Landis and Koch scale was used. MRI-findings achieving substantial reliability was considered acceptable.

RESULTS

Inter-rater reliability for all raters combined, ranged from (Gwet's AC1 or AC2): 0.64-0.99 and according to probabilistic benchmarking to the Landis and Koch scale equivalent to moderate to almost perfect reliability. Overall reliability level for individual pathologies was almost perfect reliability for spondylolisthesis, spinal stenosis, scoliosis and annular fissure, substantial for nerve root compromise and disc degeneration, and moderate for facet joint degeneration and disc contour.

CONCLUSION

Inter-rater reliability for 3 raters, evaluating 177 disc levels, was found to be overall acceptable for 6 out of 8 degenerative MRI-findings in the lumbar spine. Ratings of facet joint degeneration and disc contour achieved moderate reliability and was considered unacceptable.

Does bone scintigraphy show Modic changes associated with increased bone turnover?

Purpose

Our purpose was to evaluate whether Modic changes (MC) revealed in lumbar MRI are associated with increased tracer uptake shown in bone scintigraphy. To our knowledge, this has not previously been studied.

Methods

We included patients with MC shown in lumbar MRI and bone scintigraphy performed within six months before or after MRI. Exclusion criteria included metastasis and other specific lesions in the area of interest such as discitis, tumors or fractures. We compared the level and type of MC to the degree of tracer uptake shown in bone scintigraphy. Tracer uptake was assessed both visually and quantitatively. We calculated the lesion-to-normal-bone ratios between the MC area with increased tracer uptake and the vertebra with normal tracer uptake. We used linear mixed models in statistical analyses.

Results

Our study sample consisted of 93 patients (aged 37-86) with 299 MC (28 Type 1 (M1), 50 mixed Type 1/2 (M1/2), 3 mixed Type 1/3 (M1/3), 211 Type 2 (M2), 6 mixed Type 2/3 (M2/3), and 1 Type 3 (M3)). Of all the MC, 26 (93 %) M1, 34 (64 %) in the combined M1/2 and M1/3 group, and 11 (5 %) in the combined M2, M2/3 and M3 group showed increased tracer uptake. The mean lesion-to-normal-bone ratio was higher for lesions with a Type 1 component (M1, M1/2 and M1/3) than for other types, at 1.55 (SD 0.16) for M1; 1.44 (SD 0.21) for combined M1/2 and M1/3; and 1.28 (SD 0.11) for combined M2, M2/3 and M3; p = 0.001).

Conclusion

In most cases, MC with a Type 1 component showed increased tracer uptake in bone scintigraphy. This indicates that bone turnover is accelerated in the M1 area.

Imaging in Spine Surgery: Current Concepts and Future Directions

OBJECTIVE

To review and highlight the historical and recent advances of imaging in spine surgery and to discuss current applications and future directions.

METHODS

A PubMed review of the current literature was performed on all relevant articles that examined historical and recent imaging techniques used in spine surgery. Studies were examined for their thoroughness in description of various modalities and applications in current and future management.

RESULTS

We reviewed 97 articles that discussed past, present, and future applications for imaging in spine surgery. Although most historical approaches relied heavily upon basic radiography, more recent advances have begun to expand upon advanced modalities, including the integration of more sophisticated equipment and artificial intelligence.

CONCLUSIONS

Since the days of conventional radiography, various modalities have emerged and become integral components of the spinal surgeon's diagnostic armamentarium. As such, it behooves the practitioner to remain informed on the current trends and potential developments in spinal imaging, as rapid adoption and interpretation of new techniques may make significant differences in patient management and outcomes. Future directions will likely become increasingly sophisticated as the implementation of machine learning, and artificial intelligence has become more commonplace in clinical practice.

Utility of bone SPECT/CT to identify the primary cause of pain in elderly patients with degenerative lumbar spine disease

Background

Diagnosis of the cause of low back pain in the presence of degenerative spine disease using conventional imaging techniques, especially in elderly individuals, is challenging. Our aim was to describe our use of bone scintigraphy with single photon emission computed tomography (bone SPECT/CT) in the assessment of low back pain in elderly patients with degenerative lumbar spine disease, underlining the clinical utility of bone SPECT/CT imaging in this clinical population to inform diagnosis and treatment.

Methods

Between January 2016 and December 2017, we used bone SPECT/CT to successfully identify the cause of low back pain in five elderly patients. All patients had been scheduled for extensive spinal fusion surgery based on conventional imaging (plain radiography, computed tomography, and magnetic resonance).

Results

After diagnosis using bone SPECT/CT, three patients underwent spinal fusion at 1–2 levels with specific degenerative disk and joint disease, with the other two patients successfully treated using a conservative approach for a non-traumatic insufficiency fracture of the endplate of the L4 vertebral body and a fracture of the transverse process of L3. Clinically meaningful decrease in pain and fracture healing were obtained with conservative treatment.

Conclusion

Bone SPECT/CT was useful to identify the specific cause of pain in elderly patients with lumbar degenerative disease and to provide appropriate treatment, avoiding the unnecessary use of invasive spinal fusion surgery. Therefore, the clinical utility of bone SPECT/CT is potentially high as it improves diagnosis and lowers the risk of inappropriate invasive spinal surgery.

Presence of Modic type 1 change increases risk of postoperative pyogenic discitis following decompression surgery for lumbar canal stenosis

STUDY DESIGN

Multicenter retrospective study.

BACKGROUND

Postoperative surgical site infection is one of the most serious complications following spine surgery. Previous studies do not appear to have investigated pyogenic discitis following lumbar laminectomy without discectomy. This study aimed to identify risk factors for postoperative pyogenic discitis following lumbar decompression surgery.

METHODS

We examined data from 2721 patients undergoing lumbar laminectomy without discectomy in five hospitals from April 2007 to March 2012. Patients who developed postoperative discitis following laminectomy (Group D) and a 4:1 matched cohort (Group C) were included. Fisher's exact test was used to determine risk factors, with values of p < 0.05 considered statistically significant.

RESULTS

The cumulative incidence of postoperative discitis was 0.29% (8/2721 patients). All patients in Group D were male, with a mean age of 71.6 ± 7.2 years. Postoperative discitis was at L1/2 in 1 patient, at L3/4 in 3 patients, and at L4/5 in 4 patients. Except for 1 patient with discitis at L1/2, every patient developed discitis at the level of decompression. The associated pathogens were methicillin-resistant Staphylococcus aureus (n = 3, 37.5%), methicillin-susceptible Staphylococcus epidermidis (n = 1, 12.5%), methicillin-sensitive S. aureus (n = 1, 12.5%), and unknown (n = 3, 37.5%). In the analysis of risk factors for postoperative discitis, Group D showed a significantly lower ratio of patients who underwent surgery in the winter and a significantly higher ratio of patients who had Modic type 1 in the lumbar vertebrae compared to Group C.

CONCLUSIONS

Although further prospective studies, in which other preoperative modalities are used for the evaluation, is needed, our data suggest the presence of Modic type 1 as a risk factor for discitis following laminectomy. Latent pyogenic discitis should be carefully ruled out in patients with Modic type 1. If lumbar laminectomy is performed for such patients, more careful observation is necessary to prevent the development of postoperative discitis.

Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study

BACKGROUND CONTEXT

The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP.

PURPOSE

To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II).

STUDY DESIGN

A prospective comparative study.

PATIENT SAMPLE

Two hundred patients were enrolled: 96 in Group I and 104 in Group II.

OUTCOME MEASURES

Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records.

METHODS

Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest.

RESULTS

The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this score rises to 7.02, indicative of a high sensitivity.

CONCLUSIONS

Single-photon emission computerized tomography with computerized tomography might have potential in the diagnostic workup of patients with ns CLBP, owing to its higher sensitivity when compared with other advanced medical imaging modalities.

Evaluation of Efficacy of Bone Scan With SPECT/CT in the Management of Low Back Pain: A Study Supported by Differential Diagnostic Local Anesthetic Blocks

INTRODUCTION

Conventional radiologic modalities provide details only about the anatomic aspect of the various structures of the spine. Frequently the structures that show abnormal morphology may not be the cause of low back pain (LBP). Functional imaging in the form of bone scan along with single photon emission computerized tomography (SPECT/CT) may be helpful in identifying structures causing pain, whether morphologically normal or not. The objective of this study is to evaluate the role of bone scan with SPECT/CT in management of patients with LBP.

METHODS

This is randomized double-blinded controlled study performed on 80 patients with LBP aged 20 to 80 years, ASA physical status I to III. Patients were randomized into bone scan and control groups consisting of 40 patients each. On the basis of the clinical features and radiologic findings a clinical diagnosis was made. After making a clinical diagnosis, the patients in bone scan group were subjected to bone scan with SPECT/CT. On the basis of the finding of the bone scan and SPECT/CT, a new working diagnosis was made and intervention was performed according to the new working diagnosis. Diagnostic blocks in the control group were given based on clinical diagnosis. Controlled comparative diagnostic blocks were performed with local anesthetic. The pain score just after the diagnostic block and at the time of discharge (approximately 4 h later) was recorded; the pain relief was recorded in percentage.

RESULTS

In both the groups, sacroilitis was the most common diagnosis followed by facet joint arthropathy. The number of patients obtaining pain relief of >50% was significantly higher in the bone scan-positive group as compared with the control group. Three new clinical conditions were identified in the bone scan group. These conditions were multiple myeloma, avascular necrosis of the femoral head, and ankylosing spondylitis.

CONCLUSIONS

Bone scan with SPECT/CT was found to complement the clinical workup of patients with LBP. Inclusion of bone scan with SPECT/CT in LBP management protocol can help in making a correct diagnosis. At times it might bring out some new information that may be vital for further management of the patients with LBP.

Comparison of Outcomes in MRI Confirmed Lumbar Disc Herniation Patients With and Without Modic Changes Treated With High Velocity, Low Amplitude Spinal Manipulation

OBJECTIVE

The purpose of this study was to determine if there is a difference in outcomes between Modic positive and negative lumbar disc herniation (LDH) patients treated with spinal manipulative therapy (SMT).

METHODS

This prospective outcomes study includes 72 MRI confirmed symptomatic LDH patients treated with SMT. Numerical rating scale (NRS) pain and Oswestry disability data were collected at baseline. NRS, patient global impression of change to assess overall improvement, and Oswestry data were collected at 2 weeks, 1, 3, 6 months and 1 year. MRI scans were analyzed for Modic change present/absent and classified as Modic I or II when present. Chi-squared test compared the proportion of patients reporting relevant 'improvement' between patients with and without Modic changes and those with Modic I vs. II. NRS and Oswestry scores were compared at baseline and change scores at all follow-up time points using the unpaired Student t test.

RESULTS

76.5% of Modic positive patients reported 'improvement' compared to 53.3% of Modic negative patients (P = .09) at 2 weeks. Modic positive patients had larger decreases in leg pain (P = .02) and disability scores (P = .012) at 2 weeks. Modic positive patients had larger reductions in disability levels at 3 (P = .049) and 6 months (P = .001). A significant difference (P = .001) between patients with Modic I vs. Modic II was found at 1 year, where Modic II patients did significantly better.

CONCLUSION

Modic positive patients reported higher levels of clinically relevant improvement 2 weeks, 3 and 6 months compared to Modic negative patients. However, at 1 year Modic I patients were significantly less likely to report 'improvement', suggesting they may be prone to relapse.

The Pfirrmann classification of lumbar intervertebral disc degeneration: an independent inter- and intra-observer agreement assessment

PURPOSE

Grading inter-vertebral disc degeneration (IDD) is important in the evaluation of many degenerative conditions, including patients with low back pain. Magnetic resonance imaging (MRI) is considered the best imaging instrument to evaluate IDD. The Pfirrmann classification is commonly used to grade IDD; the authors describing this classification showed an adequate agreement using it; however, there has been a paucity of independent agreement studies using this grading system. The aim of this study was to perform an independent inter- and intra-observer agreement study using the Pfirrmann classification.

METHODS

T2-weighted sagittal images of 79 patients consecutively studied with lumbar spine MRI were classified using the Pfirrmann grading system by six evaluators (three spine surgeons and three radiologists). After a 6-week interval, the 79 cases were presented to the same evaluators in a random sequence for repeat evaluation. The intra-class correlation coefficient (ICC) and the weighted kappa (wκ) were used to determine the inter- and intra-observer agreement.

RESULTS

The inter-observer agreement was excellent, with an ICC = 0.94 (0.93-0.95) and wκ = 0.83 (0.74-0.91). There were no differences between spine surgeons and radiologists. Likewise, there were no differences in agreement evaluating the different lumbar discs. Most differences among observers were only of one grade. Intra-observer agreement was also excellent with ICC = 0.86 (0.83-0.89) and wκ = 0.89 (0.85-0.93).

CONCLUSIONS

In this independent study, the Pfirrmann classification demonstrated an adequate agreement among different observers and by the same observer on separate occasions. Furthermore, it allows communication between radiologists and spine surgeons.

Diagnostic Accuracy of Lumbosacral Spine Magnetic Resonance Image Reading by Chiropractors, Chiropractic Radiologists, and Medical Radiologists

STUDY DESIGN

A cross-sectional diagnostic accuracy study was conducted in 2 sessions.

OBJECTIVE

It is important to know whether it is possible to accurately detect "specific findings" on lumbosacral magnetic resonance (MR) images and whether the results of different observers are comparable.

SUMMARY OF BACKGROUND DATA

Health care providers frequently use magnetic resonance imaging in the diagnostic process of patients with low back pain. The use of MR scans is increasing. This leads to an increase in costs and to an increase in risk of inaccurately labeling patients with an anatomical diagnosis that might not be the actual cause of symptoms.

METHODS

A set of 300 blinded MR images was read by medical radiologists, chiropractors, and chiropractic radiologists in 2 sessions. Each assessor read 100 scans in round 1 and 50 scans in round 2. The reference test was an expert panel.For all analyses, the magnetic resonance imaging findings were dichotomized into "specific findings" or "no specific findings." For the agreement, percentage agreement and κ values were calculated and for validity, sensitivity, and specificity. Sensitivity analysis was done for classifications A and B (prevalence of 31% and 57%, respectively).

RESULTS

The intraobserver κ values for chiropractors, chiropractic radiologists, and medical radiologists were 0.46, 0.49, and 0.69 for A and 0.55, 0.75, and 0.64 for B, respectively.The interobserver κ values were lowest for chiropractors (0.28 for A, 0.37 for B) and highest for chiropractic radiologists (0.50 for A, 0.49 for B).The sensitivities of the medical radiologists, chiropractors, and chiropractic radiologists were 0.62, 0.71, and 0.75 for A and 0.70, 0.74, 0.84 for B, respectively.The specificities of medical radiologists, chiropractic radiologists, and chiropractors were 0.82, 0.77, and 0.70 for A and 0.74, 0.52, and 0.61 for B, respectively.

CONCLUSION

Agreement and validity of MR image readings of chiropractors and chiropractic and medical radiologists is modest at best. This study supports recommendations in clinical guidelines against routine use of magnetic resonance imaging in patients with low back pain.

LEVEL OF EVIDENCE

3.

Reliability of gadolinium-enhanced magnetic resonance imaging findings and their correlation with clinical outcome in patients with sciatica

BACKGROUND CONTEXT

Gadolinium-enhanced magnetic resonance imaging (Gd-MRI) is often performed in the evaluation of patients with persistent sciatica after lumbar disc surgery. However, correlation between enhancement and clinical findings is debated, and limited data are available regarding the reliability of enhancement findings.

PURPOSE

To evaluate the reliability of Gd-MRI findings and their correlation with clinical findings in patients with sciatica.

STUDY DESIGN

Prospective observational evaluation of patients who were enrolled in a randomized trial with 1-year follow-up.

PATIENTS SAMPLE

Patients with 6- to 12-week sciatica, who participated in a multicentre randomized clinical trial comparing an early surgery strategy with prolonged conservative care with surgery if needed. In total 204 patients underwent Gd-MRI at baseline and after 1 year.

OUTCOME MEASURES

Patients were assessed by means of the Roland Disability Questionnaire (RDQ) for sciatica, visual analog scale (VAS) for leg pain, and patient-reported perceived recovery at 1 year. Kappa coefficients were used to assess interobserver reliability.

METHODS

In total, 204 patients underwent Gd-MRI at baseline and after 1 year. Magnetic resonance imaging findings were correlated to the outcome measures using the Mann-Whitney U test for continuous data and Fisher exact tests for categorical data.

RESULTS

Poor-to-moderate agreement was observed regarding Gd enhancement of the herniated disc and compressed nerve root (kappa<0.41), which was in contrast with excellent interobserver agreement of the disc level of the herniated disc and compressed nerve root (kappa>0.95). Of the 59 patients with an enhancing herniated disc at 1 year, 86% reported recovery compared with 100% of the 12 patients with nonenhancing herniated discs (p=.34). Of the 12 patients with enhancement of the most affected nerve root at 1 year, 83% reported recovery compared with 85% of the 192 patients with no enhancement (p=.69). Patients with and without enhancing herniated discs or nerve roots at 1 year reported comparable outcomes on RDQ and VAS-leg pain.

CONCLUSIONS

Reliability of Gd-MRI findings was poor-to-moderate and no correlation was observed between enhancement and clinical findings at 1-year follow-up.

Interrater and intrarater agreements of magnetic resonance imaging findings in the lumbar spine: significant variability across degenerative conditions

BACKGROUND CONTEXT

Magnetic resonance imaging (MRI) is frequently used in the evaluation of degenerative conditions in the lumbar spine. The relative interrater and intrarater agreements of MRI findings across different pathologic conditions are underexplored, as most studies are focused on specific findings.

PURPOSE

The purpose of this study was to characterize the interrater and intrarater agreements of MRI findings used to assess the degenerative lumbar spine.

STUDY DESIGN

A retrospective diagnostic study at a large academic medical center was undertaken with a panel of orthopedic surgeons and musculoskeletal radiologists to assess lumbar MRIs using standardized criteria.

PATIENT SAMPLE

Seventy-five subjects who underwent routine lumbar spine MRI at our institution were included.

OUTCOME MEASURES

Each MRI study was assessed for 10 lumbar degenerative findings using standardized criteria. Lumbar vertebral levels were assessed independently, where applicable, for a total of 52 data points collected per study.

METHODS

T2-weighted axial and sagittal MRI sequences were presented in random order to the four reviewers (two orthopedic spine surgeons and two musculoskeletal radiologists) independently to determine interrater agreement. The first 10 studies were reevaluated at the end to determine intrarater agreement. Images were assessed using standardized and pilot-tested criteria to assess disc degeneration, stenosis, and other degenerative changes. Interrater and intrarater absolute percent agreements were calculated. To highlight the most clinically important MRI disagreements, a modified agreement analysis was also performed (in which disagreements between the lowest two severity grades for applicable conditions were ignored). Fleiss kappa coefficients for interrater agreement were determined.

RESULTS

The overall absolute and modified interrater agreements were 76.9% and 93.5%, respectively. The absolute and modified intrarater agreements were 81.3% and 92.7%, respectively. Average Fleiss kappa coefficient was 0.431, suggesting moderate overall agreement. However, when stratified by condition, absolute interrater agreement ranged from 65.1% to 92.0%. Disc hydration, disc space height, and bone marrow changes exhibited the lowest absolute interrater agreements. The absolute intrarater agreement had a narrower range, from 74.5% to 91.5%. Fleiss kappa coefficients ranged from fair-to-substantial agreement (0.282-0.618).

CONCLUSIONS

Even in a study using standardized evaluation criteria, there was significant variability in the interrater and intrarater agreements of MRI in assessing different degenerative conditions of the lumbar spine. Clinicians should be aware of the condition-specific diagnostic limitations of MRI interpretation.

Spondyloarthritis-related and degenerative MRI changes in the axial skeleton--an inter- and intra-observer agreement study

Background

The Back Pain Cohort of Southern Denmark (BaPa Cohort) was initiated with the aim of evaluating the clinical relevance of magnetic resonance imaging (MRI) in the diagnosis of early spondyloarthritis (SpA). In order to facilitate the collection of MRI data for this study, an electronic evaluation form was developed including both SpA-related and degenerative axial changes. The objective of the current study was to assess the intra- and inter-observer agreement of the MRI changes assessed.

Methods

Three radiologists evaluated 48 MRI scans of the whole spine and the sacroiliac joints from a subsample of the BaPa Cohort, consisting of patients with non-specific low back pain and patients with different stages of SpA features. The spine was evaluated for SpA-related and degenerative MRI changes and the SIJ for SpA-related changes. Inter- and intra-observer agreements were calculated with kappa statistics. In the interpretation of the kappa coefficient, the standards for strength of agreement reported by Landis and Koch were followed.

Results

A total of 48 patients, 40% men and mean age of 31 years (range 18 – 40 years), were evaluated once by all three readers and re-evaluated by two of the readers after 4-12 weeks. For MRI changes in the spine, substantial to almost perfect observer agreement was found for the location and the size of vertebral signal changes and for disc degeneration and disc contour. For the sacroiliac joints, substantial or almost perfect observer agreement was found for the grading of bone marrow oedema and fatty marrow deposition, the depth of bone marrow oedema and for subchondral sclerosis. Global assessment of the SpA diagnosis had substantial to almost perfect observer agreements.

Conclusion

The acceptable agreement for key MRI changes in the spine and sacroiliac joints makes it possible to use these MRI changes in the BaPa Cohort study and other studies investigating MRI changes in patients with non-specific low back pain and suspected SpA.

Magnetic resonance imaging interpretation in patients with sciatica who are potential candidates for lumbar disc surgery

Background

Magnetic Resonance Imaging (MRI) is considered the mainstay imaging investigation in patients suspected of lumbar disc herniations. Both imaging and clinical findings determine the final decision of surgery. The objective of this study was to assess MRI observer variation in patients with sciatica who are potential candidates for lumbar disc surgery.

Methods

Patients for this study were potential candidates (n = 395) for lumbar disc surgery who underwent MRI to assess eligibility for a randomized trial. Two neuroradiologists and one neurosurgeon independently evaluated all MRIs. A four point scale was used for both probability of disc herniation and root compression, ranging from definitely present to definitely absent. Multiple characteristics of the degenerated disc herniation were scored. For inter-agreement analysis absolute agreements and kappa coefficients were used. Kappa coefficients were categorized as poor (<0.00), slight (0.00–0.20), fair (0.21–0.40), moderate (0.41–0.60), substantial (0.61–0.80) and excellent (0.81–1.00) agreement.

Results

Excellent agreement was found on the affected disc level (kappa range 0.81–0.86) and the nerve root that most likely caused the sciatic symptoms (kappa range 0.86–0.89). Interobserver agreement was moderate to substantial for the probability of disc herniation (kappa range 0.57–0.77) and the probability of nerve root compression (kappa range 0.42–0.69). Absolute pairwise agreement among the readers ranged from 90–94% regarding the question whether the probability of disc herniation on MRI was above or below 50%. Generally, moderate agreement was observed regarding the characteristics of the symptomatic disc level and of the herniated disc.

Conclusion

The observer variation of MRI interpretation in potential candidates for lumbar disc surgery is satisfactory regarding characteristics most important in decision for surgery. However, there is considerable variation between observers in specific characteristics of the symptomatic disc level and herniated disc.

Lumbar modic changes-a comparison between findings at low- and high-field magnetic resonance imaging

STUDY DESIGN

A cross-sectional observational study.

OBJECTIVE

To investigate whether there is a difference in findings of lumbar Modic changes in low-field (0.3 T) magnetic resonance imaging (MRI) compared with high-field (1.5 T).

SUMMARY OF BACKGROUND DATA

It is a challenge to give patients with low back pain a specific diagnosis. Modic changes as seen on MRI have been reported to be a possible source of pain. However, it is unclear whether the diagnosis is independent on the field strength.

METHODS

Twenty patients with Modic changes, 11 women and 9 men (mean age, 53.6 yr; range, 29-81 yr), with or without sciatica, seen in a Danish outpatient low back pain clinic were included. All patients obtained MRI scans on both a high-field and a low-field MRI scanner. Two radiologists evaluated all lumbar endplates independently, using a standardized evaluation protocol. Kappa statistics were used to analyze the interobserver reproducibility. We used paired t test to analyze the difference between low- and high-field MRI.

RESULTS

The total number of Modic changes diagnosed with high-field MRI was significantly higher than that with low-field MRI. However, 3 to 4 times as many Modic type 1 changes were found with low-field MRI compared with high-field MRI. Contrarily, with high-field MRI type 2 changes were diagnosed twice as often.

CONCLUSION

There was a significant difference between low- and high-field MRI regarding the overall prevalence of any Modic change, but this had opposite directions for types 1 and 2: type 2 dominated in high field and conversely in high field [corrected]. The type of MRI unit should be taken into consideration when diagnosing patients with Modic changes

A narrative review of evidence-based recommendations for the physical examination of the lumbar spine, sacroiliac and hip joint complex

Non-specific low back pain is a frequent complaint in primary care, but the differential diagnosis for low back pain can be complex. Despite advances in diagnostic imaging, a specific pathoanatomical source of low back pain can remain elusive in up to 85% of individuals. Best practice guidelines recommend that clinicians conduct a focused physical examination to help to identify patients with non-specific low back pain and an evidence-based course of clinical management. The use of sensitive and specific clinical methods to assess the lumbar spine, sacroiliac and hip joints is critical for effective physical examination. Psychosocial factors also play an important role in the evaluation of individuals with low back pain, but are not included in this narrative review of physical examination methods. Physical examination of the lumbar spine, sacroiliac and hip joints is presented, organized around patient position for efficient and effective clinical assessment.

Inexperienced clinicians can extract pathoanatomic information from MRI narrative reports with high reproducibility for use in research/quality assurance

Background

Although reproducibility in reading MRI images amongst radiologists and clinicians has been studied previously, no studies have examined the reproducibility of inexperienced clinicians in extracting pathoanatomic information from magnetic resonance imaging (MRI) narrative reports and transforming that information into quantitative data. However, this process is frequently required in research and quality assurance contexts. The purpose of this study was to examine inter-rater reproducibility (agreement and reliability) among an inexperienced group of clinicians in extracting spinal pathoanatomic information from radiologist-generated MRI narrative reports.

Methods

Twenty MRI narrative reports were randomly extracted from an institutional database. A group of three physiotherapy students independently reviewed the reports and coded the presence of 14 common pathoanatomic findings using a categorical electronic coding matrix. Decision rules were developed after initial coding in an effort to resolve ambiguities in narrative reports. This process was repeated a further three times using separate samples of 20 MRI reports until no further ambiguities were identified (total n = 80). Reproducibility between trainee clinicians and two highly trained raters was examined in an arbitrary coding round, with agreement measured using percentage agreement and reliability measured using unweighted Kappa (k). Reproducibility was then examined in another group of three trainee clinicians who had not participated in the production of the decision rules, using another sample of 20 MRI reports.

Results

The mean percentage agreement for paired comparisons between the initial trainee clinicians improved over the four coding rounds (97.9-99.4%), although the greatest improvement was observed after the first introduction of coding rules. High inter-rater reproducibility was observed between trainee clinicians across 14 pathoanatomic categories over the four coding rounds (agreement range: 80.8-100%; reliability range k = 0.63-1.00). Concurrent validity was high in paired comparisons between trainee clinicians and highly trained raters (agreement 97.8-98.1%, reliability k = 0.83-0.91). Reproducibility was also high in the second sample of trainee clinicians (inter-rater agreement 96.7-100.0% and reliability k = 0.76-1.00; intra-rater agreement 94.3-100.0% and reliability k = 0.61-1.00).

Conclusions

A high level of radiological training is not required in order to transform MRI-derived pathoanatomic information from a narrative format to a quantitative format with high reproducibility for research or quality assurance purposes.

Inter- and intraobserver reliability in radiographic assessment of degenerative disk disease

Clinicians use descriptive classification systems when treating patients with low back pain as an adjunct to surgical decision making. Magnetic resonance imaging (MRI) changes, including Modic changes, the presence of a high-intensity zone, and internal disk desiccation, are commonly used descriptors. The question remains whether different clinicians interpret these terms similarly. This study evaluated the inter- and intraobserver reliability of commonly used MRI classifications in patients presenting with low back pain.Sixty-six patients who underwent lumbar spine fusion surgery at a single multiphysician spine specialty practice for degenerative disk disease were identified. For each surgical level, the following MRI variables were determined independently by 3 fellowship-trained spine surgeons: presence or absence of high-intensity zone and/or internal disk desiccation, presence and classification of disk herniation, Modic grade, and disk height. Each surgeon reviewed the same set of MRI studies a second time at least 2 weeks from the first reading. Inter- and intraobserver reliability was determined using multiobserver Kappa coefficients. Intraobserver reliability ranged from 0.563 to 0.988, with greatest agreement in determining disk height. The greatest interobserver agreement was for determining Modic changes (0.819).Controversy remains on the criteria for diagnosing degenerative disk disease. In patients presenting with low back pain diagnosed with degenerative disk disease, the inter- and intraobserver reliability with use of several common MRI diagnostic tools was substantial. These data imply that clinicians interpret these findings in a reproducible fashion and interpret these terms similarly.

Potential of magnetic resonance imaging findings to refine case definition for mechanical low back pain in epidemiological studies: a systematic review

STUDY DESIGN

systematic review and meta-analysis.

OBJECTIVE

to assess how confidently low back pain (LBP) can be attributed to abnormalities on magnetic resonance imaging (MRI), and thereby explore the potential value of MRI abnormalities in refining case definition for mechanical LBP in epidemiological research.

SUMMARY OF BACKGROUND DATA

most epidemiological studies of mechanical LBP have defined cases only by reported symptoms, but it is possible that the potency of causes differs depending on whether there is demonstrable underlying spinal pathology.

METHODS

we reviewed the published data on MRI abnormalities, looking for data on the repeatability of their assessment, their prevalence in people free from LBP, and their association with LBP. Where data were sufficient, we calculated a summary estimate of prevalence in people without LBP and a meta-estimate of the odds ratio for the association with LBP. A formula was then applied to estimate the corresponding prevalence rate ratio, assuming 3 possible prevalence rates for LBP in the general population.

RESULTS

data were most extensive for disc protrusion, nerve root displacement or compression, disc degeneration, and high intensity zone, all of which could be assessed repeatedly. All were associated with LBP, meta-estimates of odds ratios ranging from 2.3 (nerve root displacement or compression) to 3.6 (disc protrusion). However, even for disc protrusion, estimates of the corresponding prevalence rate ratios were mostly less than 2.

CONCLUSION

MRI findings of disc protrusion, nerve root displacement or compression, disc degeneration, and high intensity zone are all associated with LBP, but individually, none of these abnormalities provides a strong indication that LBP is attributable to underlying pathology. This limits their value in refining epidemiological case definitions for LBP.

Toward a clinical lumbar CAD: herniation diagnosis

PURPOSE

A CAD system for lumbar disc degeneration and herniation based on clinical MR images can aid diagnostic decision-making provided the method is robust, efficient, and accurate.

MATERIAL AND METHODS

A Bayesian-based classifier with a Gibbs distribution was designed and implemented for diagnosing lumbar disc herniation. Each disc is segmented with a gradient vector flow active contour model (GVF-snake) to extract shape features that feed a classifier. The GVF-snake is automatically initialized with an inner boundary of the disc initiated by a point inside the disc. This point is automatically generated by our previous work on lumbar disc labeling. The classifier operates on clinical T2-SPIR weighted sagittal MRI of the lumbar area. The classifier is applied slice-by-slice to tag herniated discs if they are classified as herniated in any of the 2D slices. This technique detects all visible herniated discs regardless of their location (lateral or central). The gold standard for the ground truth was obtained from collaborating radiologists by analyzing the clinical diagnosis report for each case.

RESULTS

An average 92.5% herniation diagnosis accuracy was observed in a cross-validation experiment with 65 clinical cases. The random leave-out experiment runs ten rounds; in each round, 35 cases were used for testing and the remaining 30 cases were used for training.

CONCLUSION

An automatic robust disk herniation diagnostic method for clinical lumbar MRI was developed and tested. The method is intended for clinical practice to support reliable decision-making.

Single photon emission computerized tomography (SPECT) scan-positive facet joints and other spinal structures in a hospital-wide population with spinal pain

BACKGROUND CONTEXT

The current criterion standard for zygapophyseal (facet) joint pain diagnosis is placebo-controlled triple comparative local anesthetic facet joint or medial branch blocks. Single photon emission computerized tomography (SPECT) scanning is a less invasive modality that has been widely used in patients with spinal pain for the diagnosis of facet joint arthritis. Previous studies have shown that SPECT results correlate well with response to facet joints steroid injections.

PURPOSE

To evaluate the prevalence of SPECT scan-positive facet joints and other spinal areas in different age groups in a hospital-wide population with spinal pain.

STUDY DESIGN

Retrospective study.

METHODS

This study included 534 patients who underwent a SPECT scan for spinal pain over 7.5 years in our hospital. All referrals from all doctors for any cervical or lumbar spinal pain were included, and the results were reviewed.

RESULTS

A total of 486 patients (91.1%) had at least one positive abnormality on SPECT scan; 81.3% had increased uptake in different structures and regions of the spine. This included 42.8% increased uptake in the facet joint 29.8% in the vertebral bodies/end plates, and 5.9% in sacroiliac joints. The prevalence of increased uptake in the lumbosacral and cervical spine was 44% and 37%, respectively. When patients were divided into five age groups (below 40, 40-49, 50-59, 60-69, and 70 years and older), there was a significantly higher increased prevalence in advancing age groups.

CONCLUSIONS

In a hospital-wide population with spinal pain, there is a 42.88% prevalence of increased uptake in the facet joint on SPECT. The incidence increases significantly with advancing age. SPECT can play a role in investigating patients with spinal pain.

Characteristics and natural course of vertebral endplate signal (Modic) changes in the Danish general population

BACKGROUND

Vertebral endplate signal changes (VESC) are more common among patients with low back pain (LBP) and/or sciatica than in people who are not seeking care for back pain. The distribution and characteristics of VESC have been described in people from clinical and non-clinical populations. However, while the clinical course of VESC has been studied in patients, the natural course in the general population has not been reported. The objectives of this prospective observational study were to describe: 1) the distribution and characteristics of VESC in the lumbar spine, 2) its association with disc degeneration, and 3) its natural course from 40 to 44 years of age.

METHODS

Three-hundred-and-forty-four individuals (161 men and 183 women) sampled from the Danish general population had MRI at the age of 40 and again at the age of 44. The following MRI findings were evaluated using standardised evaluation protocols: type, location, and size of VESC, disc signal, and disc height. Characteristics and distribution of VESC were analysed by frequency tables. The association between VESC and disc degeneration was analysed by logistic regression analysis. The change in type and size of VESC was analysed by cross-tabulations of variables obtained at age 40 and 44 and tested using McNemar's test of symmetry.

RESULTS

Two-thirds (67%) of VESC found in this study were located in the lower part of the spine (L4-S1). VESC located at disc levels L1-L3 were generally small and located only in the anterior part of the vertebra, whereas those located at disc levels L4-S1 were more likely to extend further into the vertebra and along the endplate. Moreover, the more the VESC extended into the vertebra, the more likely it was that the adjacent disc was degenerated. The prevalence of endplate levels with VESC increased significantly from 6% to 9% from age 40 to 44. Again, VESC that was only observed in the endplate was more likely to come and go over the four-year period compared with those which extended further into the vertebra, where it generally persisted.

CONCLUSION

The prevalence of VESC increased significantly over the four-year period. Furthermore, the results from this study indicate that the distribution of VESC, its association with disc degeneration and its natural course, is dependent on the size of the signal changes.

Lumbar spine: reliability of MR imaging findings

PURPOSE

To characterize the inter- and intraobserver variability of qualitative, non-disk contour degenerative findings of the lumbar spine at magnetic resonance (MR) imaging.

MATERIALS AND METHODS

The case accrual method used to perform this institutional review board-approved, HIPAA-compliant retrospective study was the random selection of 111 interpretable MR examination cases of subjects from the Spine Patient Outcomes Research Trial. The subjects were aged 18-87 years (mean, 53 years +/- 16 [standard deviation]). Four independent readers rated the cases according to defined criteria. A subsample of 40 MR examination cases was selected for reevaluation at least 1 month later. The following findings were assessed: spondylolisthesis, disk degeneration, marrow endplate abnormality (Modic changes), posterior anular hyperintense zone (HIZ), and facet arthropathy. Inter- and intraobserver agreement in rating the data was summarized by using weighted kappa statistics.

RESULTS

Interobserver agreement was good (kappa = 0.66) in rating disk degeneration and moderate in rating spondylolisthesis (kappa = 0.55), Modic changes (kappa = 0.59), facet arthropathy (kappa = 0.54), and posterior HIZ (kappa = 0.44). Interobserver agreement in rating the extent of Modic changes was moderate: kappa Values were 0.43 for determining superior anteroposterior extent, 0.47 for determining superior craniocaudal extent, 0.57 for determining inferior anteroposterior extent, and 0.48 for determining inferior craniocaudal extent. Intraobserver agreement was good in rating spondylolisthesis (kappa = 0.66), disk degeneration (kappa = 0.74), Modic changes (kappa = 0.64), facet arthropathy (kappa = 0.69), and posterior HIZ (kappa = 0.67). Intraobserver agreement in rating the extent of Modic changes was moderate, with kappa values of 0.54 for superior anteroposterior, 0.60 for inferior anteroposterior, 0.50 for superior craniocaudal, and 0.60 for inferior craniocaudal extent determinations.

CONCLUSION

The interpretation of general lumbar spine MR characteristics has sufficient reliability to warrant the further evaluation of these features as potential prognostic indicators.

Vertebral endplate signal changes (Modic change): a systematic literature review of prevalence and association with non-specific low back pain

The prevalence of "vertebral endplate signal changes" (VESC) and its association with low back pain (LBP) varies greatly between studies. This wide range in reported prevalence rates and associations with LBP could be explained by differences in the definitions of VESC, LBP, or study sample. The objectives of this systematic critical review were to investigate the current literature in relation to the prevalence of VESC (including Modic changes) and the association with non-specific low back pain (LBP). The MEDLINE, EMBASE, and SveMED databases were searched for the period 1984 to November 2007. Included were the articles that reported the prevalence of VESC in non-LBP, general, working, and clinical populations. Included were also articles that investigated the association between VESC and LBP. Articles on specific LBP conditions were excluded. A checklist including items related to the research questions and overall quality of the articles was used for data collection and quality assessment. The reported prevalence rates were studied in relation to mean age, gender, study sample, year of publication, country of study, and quality score. To estimate the association between VESC and LBP, 2 x 2 tables were created to calculate the exact odds ratio (OR) with 95% confidence intervals. Eighty-two study samples from 77 original articles were identified and included in the analysis. The median of the reported prevalence rates for any type of VESC was 43% in patients with non-specific LBP and/or sciatica and 6% in non-clinical populations. The prevalence was positively associated with age and was negatively associated with the overall quality of the studies. A positive association between VESC and non-specific LBP was found in seven of ten studies from the general, working, and clinical populations with ORs from 2.0 to 19.9. This systematic review shows that VESC is a common MRI-finding in patients with non-specific LBP and is associated with pain. However, it should be noted that VESC may be present in individuals without LBP.

The reproducibility of quantitative measurements in lumbar magnetic resonance imaging of children from the general population

STUDY DESIGN

Quantitative lumbar magnetic resonance imaging (MRI) measurements in children were taken twice and analyzed for intra- and intertester reproducibility.

OBJECTIVE

To evaluate the reproducibility of a variety of lumbar quantitative measurements taken from MRIs of children from the general population.

SUMMARY OF BACKGROUND DATA

The reproducibility of lumbar quantitative measurements has never been tested on MRIs of children from the general population. This is a prerequisite for a reliable anatomic characterization of the immature spine in normal and pathologic conditions.

METHODS

Lumbar quantitative measurements from 40 T2-weighted lumbar (L1-S1) MRIs of children from the general population were taken twice by 1 tester for intratester reproducibility and compared with the same measurements (L4-S1) of the same MRIs taken by a second tester for intertester reproducibility. The following parameters were measured using the iQ-VIEW system (IMAGE Information Systems Ltd., version 1.2.2, Plauen, Germany): Linear measurements--zygoappophyseal facets and interfacet widths, and vertebral body (VB), pedicle and intervertebral discs heights, widths, and lengths. Angular measurements--zygoappophyseal tranverse superior facet angles, sagittal VB, and disc wedging, lumbar lordosis, and sacral inclination. Statistical analysis included the concordance correlation coefficient (CCC), and Bland and Altman's limits of agreement (LOA).

RESULTS

A total of 6160 measurements were analyzed. Good to excellent intratester reproducibility (0.75 < or =CCC < or =0.99) was indicated for all linear measurements (except for pedicle heights) (LOA: -4.76; 5.74 mm) and for angular measurements related to the facets orientation, lumbar lordosis, and sacral inclination (LOA: 11.22 degrees ; 12.34 degrees). VB and disc sagittal wedging manifested poor intratester reproducibility (CCC < 0.75). Good to excellent intertester reproducibility was indicated for 70% of all linear measurements (LOA: -5.83; 4.59 mm) and for all angular measurements in the lumbar spine (L4-S1) (LOA: -9.96 degrees ; 14.62 degrees) except for VB and disc sagittal wedging at L5 (CCC < 0.75).

CONCLUSION

Quantitative lumbar MRI measurements in children from the general population were found to be reproducible indicating a good visualization of immature vertebral anatomic margins on MRIs and an accurate definition of the measurement protocol.