Magnetic Resonance Grading Research Articles

Fat content in lumbar paravertebral muscles: Quantitative and qualitative analysis using dual-energy CT in correlation to MR imaging

PurposeThis study aims to assess the diagnostic performance of dual-energy computed tomography (DECT) on lumbar paravertebral muscles fat infiltration (PMFI) in participants with low back pain (LBP). MethodIn this prospective study, 21 participants with LBP were performed with noncontrast DECT scans within 1 week after magnetic resonance (MR) examinations. The assessment was based on the selected region of interest obtained from the paravertebral L1/L2-L5/S1 muscle. On visual evaluation, PMFI was assessed at DECT virtual monoenergetic images (80 keV) with Goutallier classification system using MR results as a reference. Quantitative parameters fat fraction, CT number, ΔCT number (difference of CT number at 140 and 80 keV), and optimal cutoff values above the indicators between MR adjacent grades were measured. ResultsIn this study, 582 ROIs from 21 participants (mean age, 60 ± 16 years old; 15 females) were evaluated. Sensitivity, specificity, and accuracy of readers 1 and 2 at severe grade (grades 3 and 4) were 67% and 85% (22 and 28 of 33), 99% and 99% (159 and 160 of 161), and 93% and 97% (181 and 188 of 194), respectively. Interobserver reliability was high with κ = 0.85 (p < 0.001). For DECT quantification parameters, significance was all represented between five grades (all p < 0.01). The area under the curve of indicators for discrimination between severe (grades 3 and 4) and normal and moderate (grades 0, 1, and 2) grades were > 0.80 (p < 0.001). ConclusionsDECT was a promising qualitative and quantitative imaging technique to assess lumbar PMFI in participants with LBP and could provide accurate quantification for different fat infiltration (FI) degrees. Moreover, visual DECT assessment could excellently distinguish severe from normal and moderate FI of MR grades.

The Value of Arterial Spin Labeling Imaging in the Classification and Prognostic Evaluation of Neonatal Hypoxic-ischemic Encephalopathy.

This study aims to investigate the correlation between cerebral blood flow (CBF) values and neonatal behavioral neurological assessment (NBNA) in hypoxic-ischemic encephalopathy (HIE), the relationship between early CBF value changes and the prognosis of neonatal HIE, and the consistency between the clinical grading and magnetic resonance (MR) grading of HIE. Forty neonates with HIE were scanned using the three-dimensional arterial spin labeling (ASL) sequencing of the cranial Magnetic Resonance Imaging (MRI). These newborns were classified as having mild, moderate and severe HIE, according to the clinical grading, and as being normal or having mild, moderate, or severe HIE, according to the MRI grading. Then, the consistency of these two grading systems was compared. Afterwards, the differences in the CBF values of neonates in groups with mild, moderate and severe HIE were compared. In addition, these neonates were grouped according to their NBNA scores. A score of ≥35 was considered a good prognosis, while a score of ≤35 was considered a poor prognosis. The differences in CBF values between these two groups were compared, and the correlation between the CBF values and NBNA scores was determined. There was a strong consistency between the evaluation results for the clinical grading and MR grading (kappa value = 0.672, P<0.001). The differences in CBF values for the basal ganglia (BG) area and thalamus, and the differences in NBNA scores for groups with mild, moderate, or severe HIE were statistically significant (P<0.05). The differences between the poor prognosis group and the good prognosis group, in terms of the CBF values for the BG area and thalamus, and the NBNA scores were statistically significant (P<0.05). The CBF values in the BG region and thalamus were closely and negatively correlated with the NBNA scores. Early CBF values in the BG area and thalamus can objectively and visually reflect the severity of the HIE, and be used to predict the outcome of functional brain damage, allowing early neuroprotective treatment to be initiated. The higher the perfusion in the BG region and thalamus, the lower the NBNA score, and the worse the prognosis would likely be. ASL combined with the NBNA score provides a more comprehensive classification for HIE and a more accurate assessment of the clinical prognosis, providing more medical imaging information for early clinical treatment.

Quantitative T2 -mapping magnetic resonance imaging for assessment of muscle motor unit recruitment patterns.

In this study, we aimed to determine whether muscle transverse relaxation time (T2 ) magnetic resonance (MR) mapping results correlate with motor unit loss, as defined by motor unit recruitment patterns on electromyography (EMG). EMG and 3-Tesla MRI exams were acquired no more than 31 days apart in subjects referred for peripheral nerve MRI. Two musculoskeletal radiologists qualitatively graded T2 -weighted, fat-suppressed sequences for severity of muscle edema-like patterns and manually placed regions of interest within muscles to obtain T2 values from T2 -mapping sequences. Concordance was calculated between qualitative and quantitative MR grades and EMG recruitment categories (none, discrete, decreased) as well as interobserver agreement for both MR grades. Thirty-four muscles (21 abnormal, 13 control) were assessed in 13 subjects (5 females and 8 males; mean age, 46 years) with 14 EMG-MRI pairs. T2 -relaxation times were significantly (P < .001) increased in all EMG recruitment categories compared with control muscles. T2 differences were not significant between EMG grades of motor unit recruitment (P = .151-.702). T2 and EMG score concordance was acceptable (Harrell's concordance index [c index]: rater A, 0.71; 95% confidence interval [CI], 0.51-0.87; rater B, 0.77; 95% CI, 0.57-0.91). Qualitative MRI and EMG score concordance was poor to acceptable (c index: rater A, 0.60; 95% CI, 0.50-0.79; rater B, 0.72; 95% CI, 0.55-0.89). T2 values had moderate-to-substantial ability to distinguish between absent vs incomplete (ie, decreased or discrete) motor unit recruitment (c index: rater A, 0.78; 95% CI, 0.50-1.00; rater B, 0.86; 95% CI, 0.57-1.00). Quantitative T2 MR muscle mapping is a promising tool for noninvasive evaluation of the degree of motor unit recruitment loss.

Natural Growth Dynamics of Untreated Skull Base Chordomas In Vivo

To study the natural growth dynamics of skull base chordomas. A retrospective study of skull base chordomas was performed. Patients with ≥2 preoperative magnetic resonance (MR) images and with pathologically confirmed chordomas were enrolled. All clinical data and MR images were studied. Twenty-one patients with pathologically confirmed skull base chordomas were enrolled. The mean volume of the tumors at diagnosis was 19.9 ± 17.0 cm3, with a mean interval examination period of 22.4 ± 26.1 (range, 3-113) months. The mean tumor volume change was approximately 15.4 ± 16.3 cm3. The mean specific growth rate was 8% ± 9% per month, and the mean specific growth volume was 0.8 ± 0.7 cm3 per month. The tumor MR signal index grade, female gender, no dura mater breakthrough, endophytic type, small tumors, and soft tumor texture were related to a higher tumor growth rate (P<0.05), and small tumors showed the greatest growth rate compared with the middle-sized and large tumors. Curveestimation was performed using a power function (R2= 0.545). The skull base chordoma is a slow-growing tumor. The cases involving characteristics of female gender, endophytic type, small tumor size, and MR grade 3 showed a higher growth rate.

Is There A Relationship Between Three-Dimensionally Measured Baker's Cyst Volume and Knee Pathologies?

Baker's cyst (BC) is also known as popliteal cyst. To evaluate its effect on intra-articular pathology, it is important to have the exact volume of the cyst. As BC may change its shape due to mass effect of the surrounding anatomic structures, it is difficult to measure the exact volume of BC. This study examined the relationship between three-dimensionally measured BC volume and symptomatic intra-articular knee pathologies. The magnetic resonance (MR) images of 45 patients with symptomatic knees were retrospectively examined.The BC volumes were measured via volumetric analysis. The joint effusion was examined in the sagittal plane in T2-proton density-weighted images. The medial plicae were assessed in accordance with the modified Sakakibara classification. Using the MR images, the meniscuses were classified in accordance with the meniscus rupture classification of Stoller et al. The cartilaginous lesions were analyzed using an MR grading system.In this study, correlations between the following measures were analyzed: BC volume and effusion level, medial plica presence, medial femoral condyle, medial tibial condyle, lateral femoral condyle and lateral tibial condyle cartilage degeneration, and medial meniscus anterior horn, medial meniscus posterior horn, lateral meniscus anterior and posterior horn ruptures. Cartilage degeneration, medial plicae, increase in intra-articular effusion, and increase in the BC volume were found to be statistically significant (p<0.01). Cartilage degeneration, medial plicae, and increase in intra-articular effusion may increase the BC volume. We believe that this study may contribute to clinicians in understanding the relationship between BC volume changes and pathologies causing intra-articular knee symptoms.

Qualitative grading of disc degeneration by magnetic resonance in the lumbar and cervical spine: lack of correlation with histology in surgical cases

Background: Clinically, magnetic resonance (MR) imaging is the most effective non-invasive tool for assessing IVD degeneration. Histological examination of the IVD provides a more detailed assessment of the pathological changes at a tissue level. However, very few reports have studied the relationship between these techniques. Identifying a relationship may allow more detailed staging of IVD degeneration, of importance in targeting future regenerative therapies. Objectives: To investigate the relationship between MR and histological grading of IVD degeneration in the cervical and lumbar spine in patients undergoing discectomy. Methods: Lumbar (N = 99) and cervical (N = 106) IVD samples were obtained from adult patients undergoing discectomy surgery for symptomatic IVD herniation and graded to ascertain a histological grade of degeneration. The pre-operative MR images from these patients were graded for the degree of IVD (MR grade) and vertebral end-plate degeneration (Modic Changes, MC). The relationship between histological and MR grades of degeneration were studied. Results: In lumbar and cervical IVD the majority of samples (93%) exhibited moderate levels of degeneration (ie MR grades 3-4) on pre-operative MR scans. Histologically, most specimens displayed moderate to severe grades of degeneration in lumbar (99%) and cervical spine (93%). MR grade was weakly correlated with patient age in lumbar and cervical study groups. MR and histological grades of IVD degeneration did not correlate in lumbar or cervical study groups. MC were more common in the lumbar than cervical spine (e.g. 39 versus 20% grade 2 changes; p < 0.05), but failed to correlate with MR or histological grades for degeneration. Conclusions: In this surgical series, the resected IVD tissue displayed moderate to severe degeneration, but there is no correlation between MR and histological grades using a qualitative classification system. There remains a need for a quantitative, non-invasive, pre-clinical measure of IVD degeneration that correlates with histological changes seen in the IVD.

Do low field magnetic resonance imaging abnormalities correlate with macroscopical and histological changes within the equine deep digital flexor tendon?

Correlating magnetic resonance (MR) imaging and histopathological findings is essential to validate low field MR imaging in lame horses. This study aimed to compare signal changes in the deep digital flexor tendon (DDFT) of the distal limb on low field MR imaging with macroscopical and histological findings. Cadaver limbs from lame horses with DDFT lesions were selected. The DDFT MR imaging findings and histopathological results were graded, and macroscopical abnormalities were recorded. There was a strong correlation between MR imaging and histopathology grades (rs = 0.76, p < 0.001) in the foot. There was moderate agreement (Kappa statistic 0.52) between the MR and histopathology grades; agreement was superior further proximal in the foot. The presence and severity of pathology in the DDFT are well represented by the presence and severity of MR imaging signal changes. The study supports the use of low field MR imaging for diagnosis of equine distal limb DDFT lesions.

Magnetic resonance and radiographic diagnosis of osseous resorption of the flexor surface of the distal phalanx in the horse

Osseous resorption of the flexor surface of the distal phalanx of the horse has been identified previously using magnetic resonance (MR) imaging; however, little is known about the prevalence and characteristics of this lesion. To establish the MR prevalence of resorptive lesions in the flexor surface of the distal phalanx and identify concurrent lesions associated with this finding and associations between the MR and radiographic findings. Horses with distal extremity MR and radiographs performed within 2 weeks of each other were included in the study. The flexor surface of the distal phalanx was graded independently on both modalities for the presence of osseous resorption. The sensitivity and specificity of radiography for identifying osseous resorption was calculated using MR as the gold standard. Eighty-two MR studies met the inclusion criteria, 8 of which included osseous resorption of the flexor surface of the distal phalanx. Concurrent injury to the deep digital flexor tendon and the navicular bone was a common finding. An association between MR and radiographic grades was identified. Radiography had a high specificity (0.96) but lower sensitivity (0.45-0.55) for detecting osseous resorption. Osseous resorption of the flexor surface of the distal phalanx can be observed both on MR and radiographic examinations of horses with lameness localised to the foot. This lesion is most often associated with other pathological changes in the podotrochlear apparatus. Focal radiolucency of the flexor surface of the distal phalanx is a newly recognised radiographic sign associated with pathological changes of the podotrochlear apparatus.

Metal-on-Metal Total Hip Arthroplasty: Do Symptoms Correlate with MR Imaging Findings?

To determine the prevalence of magnetic resonance (MR) imaging abnormalities after metal-on-metal total hip arthroplasty and to determine whether presence of symptoms correlates with findings at MR imaging. This HIPAA-compliant study was approved by the institutional review board, and informed consent was waived. MR imaging was performed with conventional sequences and a 1.5-T clinical imager in 192 hips (174 patients) evaluated during a 15-month period. Two observers retrospectively reviewed the images for the presence and size of pseudotumor, communication with the pseudocapsule, wall thickness, synovial hypertrophy, compartmentalization, solid components, foci of wall susceptibility, osteolysis, bone marrow edema, abductor muscle or tendon abnormality, and Anderson MR grade (normal, infection, or varying severity of metal-on-metal disease). These findings were compared between asymptomatic and symptomatic patients by using the Fisher exact test or the Wilcoxon-Mann-Whitney test, as appropriate. Prevalence of pseudotumors per patient and per hip was 69% (120 of 174 patients, 132 of 192 hips). Bone marrow edema (present in six asymptomatic patients and 19 patients with pain, P < .01) and tendon tearing (present in five asymptomatic patients and 13 patients with pain, P < .05) were predictors of pain. Presence of symptoms was not correlated with presence (P = .4151) or size of pseudotumors. Anderson MR grade binarized into normal versus abnormal showed moderate agreement between readers (κ = 0.439) but was also not correlated with symptoms (P = .6648). The presence of bone marrow edema and abductor tendon tears but not the presence or size of pseudotumor was associated with patient pain.

Radiographic grading of facet degeneration, is it reliable?—a comparison of MR or CT grading with histologic grading in lumbar fusion candidates

The current interest in motion-sparing surgery highlights the need for a more accurate radiologic evaluation of the degree of facet degeneration. In the presence of severe facet degeneration, a surgeon cannot ensure a positive outcome, even after successful surgery. To the best of our knowledge, no prospective study has compared the accuracy of grading facet degeneration by computed tomography (CT) or magnetic resonance (MR) scans with that attained from a real histologic evaluation. The purpose of this study was to determine the accuracy and reliability of CT or MR assessments of lumbar facet degeneration by comparing it with the histologic grading of the resected facets during surgery. A prospective study of consecutive patients undergoing posterior lumbar fusion surgery. Forty-four excised facets from 18 patients who received lumbar fusion were evaluated using radiographic and histologic techniques. All patients prospectively underwent CT scanning, routine axial T2-weighted MR scanning, and axial MR using a double echo steady state (DESS) sequence for cartilage imaging. The facets were graded radiologically using four-point scales. The inferior articular processes including the cartilage and subchondral bone of the corresponding facets were resected during surgery and evaluated histologically using a four-point grading system. Radiologic grading revealed a tendency for underestimating facet degeneration than histologic grading. The number of facets undergraded by radiologic evaluations was 24 (55%) facets by CT, 16 (36%) by routine MR, and 22 (49%) by DESS. The weighted kappa coefficients between the histologic and radiologic grading also showed a poor correlation (0.120 for CT, 0.128 for routine MR, and 0.280 for MR using DESS sequence, respectively). The false-negative rates for detecting histologic degeneration by radiologic studies were 41% to 54%. The receiver operating characteristic curve revealed MR using DESS to have a better performance. The degree of facet degeneration can be underestimated by current radiologic modalities, and their ability to detect facet degeneration is quite limited. Surgeons should be aware of these limitations during a preoperative evaluation of patients considered for motion-sparing techniques in lumbar spinal surgery.

Role of Fat-Suppressed T1-Weighted Magnetic Resonance Imaging in Predicting Severity and Prognosis of Acute Pancreatitis

To determine the diagnostic value of magnetic resonance (MR) grading focusing on elevated signal on T1-weighted images in the prediction of severity and prognosis of acute pancreatitis as compared with the Balthazar computed tomography (CT) grading. Thirty-one patients with acute pancreatitis who underwent CT and MR imaging including fat-suppressed T1-weighted images within a 48-hour interval were included in this study. The severity of pancreatitis was evaluated by 2 observers using the Balthazar CT grading system and an MR grading system that is focused on an elevated signal on T1-weighted images. The MR grading was correlated with the CT grading, and each MR or CT grade was compared with patient outcome parameters, including the duration of hospitalization, local and systemic complications, and clinical outcome grading. There was a significant correlation between CT and MR gradings for pancreatic or peripancreatic inflammation (r = 0.688, P < 0.01). However, for all of the outcome parameters and outcome grading, a stronger correlation was seen with the MR grading than with the CT grading. No significant correlation was found between CT grading and infected necrosis (r = 0.316, P = 0.083). Magnetic resonance imaging including fat-suppressed T1-weighted images is more accurate to predict the severity and prognosis of acute pancreatitis in comparison with CT.

Osteochondral defect repair after implantation of biodegradable scaffolds: indirect magnetic resonance arthrography and histopathologic correlation

Biodegradable scaffolds have become an important option in the treatment of osteochondral defects. Therefore, accurate and reproducible monitoring of scaffold repair tissue is crucial. To assess the feasibility of indirect magnetic resonance (MR) arthrography in determining the quality of osteochondral repair after scaffold implantation using an MR imaging (MRI) scoring and grading system with histology as reference. Osteochondral defects created at ovine condylar facets were treated with either a commercial poly (DL-lactide-co-glycolide) (PLG) scaffold or a modified softer one (n=6/group; 87% and 55% of the elastic modulus of ovine subchondral bone, respectively). Empty defects at the contralateral condyle served as control group. A 1.5T MRI scan was performed after 6 months with proton density (PD)-weighted (w) fat-saturated (fs) fast spin-echo (FSE), T1-w two-dimensional (2D), and 3D fs gradient echo (GE) sequences 30 min after intravenous Gd-DTPA administration and passive joint movement. Two independent radiologists evaluated the repair tissue. The MR findings were correlated with histological findings. MRI and histological grading correlated well (10/12 cases). The stiff-scaffold group showed significantly superior repair in comparison to the control group (P<0.05). The 3D fs GE sequence proved to be most valuable in evaluating morphologic status. Complete defect filling and integration, intact surface and isointense signal to the adjacent native cartilage, subchondral incorporation with bone marrow edema, and graft plug enhancement were associated with a good histological outcome. Histologically, we found a smooth fibrocartilaginous layer and osseous replacement of the scaffold. Incomplete cartilage repair and irregular subchondral structures on the MRI correlated histologically with fibrocartilage-like repair and subchondral sclerosis, due to substantial degradation of the scaffold. Indirect MR arthrography is an accurate, noninvasive monitoring tool in the follow-up of scaffold implants. The MRI scoring and grading system allows reliable assessment of normal and pathological repair, with high correlation to histological findings.

In vivo T1ρ and T2 mapping of articular cartilage in osteoarthritis of the knee using 3 T MRI

Evaluation and treatment of patients with early stages of osteoarthritis (OA) is dependent upon an accurate assessment of the cartilage lesions. However, standard cartilage dedicated magnetic resonance (MR) techniques are inconclusive in quantifying early degenerative changes. The objective of this study was to determine the ability of MR T1rho (T(1rho)) and T(2) mapping to detect cartilage matrix degeneration between normal and early OA patients. Sixteen healthy volunteers (mean age 41.3) without clinical or radiological evidence of OA and 10 patients (mean age 55.9) with OA were scanned using a 3Tesla (3T) MR scanner. Cartilage volume and thickness, and T(1rho) and T(2) values were compared between normal and OA patients. The relationship between T(1rho) and T(2) values, and Kellgren-Lawrence scores based on plain radiographs and the cartilage lesion grading based on MR images were studied. The average T(1rho) and T(2) values were significantly increased in OA patients compared with controls (52.04+/-2.97ms vs 45.53+/-3.28ms with P=0.0002 for T(1rho), and 39.63+/-2.69ms vs 34.74+/-2.48ms with P=0.001 for T(2)). Increased T(1rho) and T(2) values were correlated with increased severity in radiographic and MR grading of OA. T(1rho) has a larger range and higher effect size than T(2), 3.7 vs 3.0. Our results suggest that both in vivo T(1rho) and T(2) relaxation times increase with the degree of cartilage degeneration. T(1rho) relaxation time may be a more sensitive indicator for early cartilage degeneration than T(2). The ability to detect early cartilage degeneration prior to morphologic changes may allow us to critically monitor the course of OA and injury progression, and to evaluate the success of treatment to patients with early stages of OA.

Comparison between neuroimaging classifications and histopathological diagnoses using an international multicenter brain tumor magnetic resonance imaging database

The aim of this study was to estimate the accuracy of routine magnetic resonance (MR) imaging studies in the classification of brain tumors in terms of both cell type and grade of malignancy. The authors retrospectively assessed the correlation between neuroimaging classifications and histopathological diagnoses by using multicenter database records from 393 patients with brain tumors. An ontology was devised to establish diagnostic agreement. Each tumor category was compared with the corresponding histopathological diagnoses by dichotomization. Sensitivity, specificity, positive and negative predictive values (PPVs and NPVs, respectively), and the Wilson 95% confidence intervals (CI) for each were calculated. In routine reporting of MR imaging examinations, tumor types and grades were classified with a high specificity (85.2-100%); sensitivity varied, depending on the tumor type and grade, alone or in combination. The recognition of broad diagnostic categories (neuroepithelial or meningeal lesions) was highly sensitive, whereas when both detailed type and grade were considered, sensitivity diverged, being highest in low-grade meningioma (sensitivity 100%, 95% CI 96.2-100.0%) and lowest in high-grade meningioma (sensitivity 0.0%, 95% CI 0.0-65.8%) and low-grade oligodendroglioma (sensitivity 15%, 95% CI 5.2-36.0%). In neuroepithelial tumors, sensitivity was inversely related to the precision in reporting of grade and cellular origin; "glioma" was a frequent neuroimaging classification associated with higher sensitivity in the corresponding category. The PPVs varied among categories, in general being greater than their prevalence in this dataset. The NPV was high in all categories (69.8-100%). The PPVs and NPVs provided in this study may be used as estimates of posttest probabilities of diagnostic accuracy using MR imaging. This study targets the need for noninvasively increasing sensitivity in categorizing most brain tumor types while retaining high specificity, especially in the differentiation of high- and low-grade glial tumor classes.

HOW DOES MAGNETIC RESONANCE IMAGING REPRESENT HISTOLOGIC FINDINGS IN THE EQUINE DIGIT?

Magnetic resonance (MR) imaging is increasingly used in the diagnosis of equine foot pain, but improved understanding of how MR images represent tissue-level changes in the equine foot is required. We hypothesized that alterations in signal intensity and tissue contour would represent changes in tissue structure detected using histologic evaluation. The study objectives were to determine the significance of MR signal alterations in feet from horses with and without lameness, by comparison with histopathologic changes. Fifty-one cadaver feet from horses with a history of lameness improved by palmar digital analgesia (n = 32) or age-matched control horses with no history of lameness (n = 19) were stored frozen before undergoing MR imaging and subsequent histopathological examination at standard sites (deep digital flexor tendon, navicular bone, distal sesamoidean impar ligament, collateral sesamoidean ligament, and navicular bursa). Using MR images, signal intensity and homogeneity, size, definition of anatomic margins, and relationships with other structures were described. Alterations were graded as mild, moderate, or severe for each structure. For each anatomic site examined histologically the structures were described and scored as no changes, mild, moderate, or severe abnormalities, also taking into account adhesion formation within the navicular bursa detected on macroscopic examination. Alterations in MR signal intensity were related to changes at the tissue level detected by histologic examination. A sensitivity and specificity comparison of MR imaging with histologic examination was used to evaluate the significance of MR signal alterations for detection of moderate-to-severe lesions of the deep digital flexor tendon (DDFT), navicular bone, distal sesamoidean impar ligament (DSIL), collateral sesamoidean ligament (CSL) and navicular bursa. Agreement between the MR and histologic grading was assessed for each structure using a weighted kappa agreement. Direct comparison between histology and MR imaging for individual limbs revealed that signal alterations on MR imaging did represent tissue-level changes. These included structural damage, fibroplasia, fibrocartilaginous metaplasia, and hemosiderosis in ligaments and tendons; trabecular damage, osteonecrosis, fibroplasia, cortical defects, and increased vascularity in bone; and fibrocartilage defects. MR imaging had a high sensitivity and specificity for most structures. MR imaging had high specificity for lesions of the DDFT, CSL and navicular bursa, quite high specificity for lesions of the medulla of the navicular bone and its proximal aspect, with moderate specificity for the DSIL, and distal, dorsal and palmar aspects of the navicular bone, and was sensitive for detection of abnormalities in all structures except the dorsal aspect of the navicular bone. When MR and histologic grades alone were compared, there was good agreement between MR and histologic grades for the navicular bursa, DDFT, navicular bone medulla and CSL; moderate-to-good agreement in grades of the distal and palmar aspects of the navicular bone; fair to moderate in grades of the DSIL, and poor agreement for the dorsal and proximal aspects of the navicular bone. The results of this study support our hypothesis and indicate the potential use and limitations of MR imaging for visualization of structural changes within osseous and soft tissue structures of the equine foot.

Temporomandibular joint internal derangement: relationship between joint pain and MR grading of effusion and total protein concentration in the joint fluid

The objective of this study was to determine whether there is any association between the protein concentration in the synovial fluid and (i) the amount of articular hydrops, as graded in magnetic resonance (MR) images, and (ii) joint pain in temporomandibular joints (TMJs) with and without displacement of the disc. This study involved 16 joints in 16 patients referred to our clinic with the complaint of pain and limited mouth opening. The control group consisted of 15 joints in 15 patients with unilaterally normal disc and condyle relationship and no pain while the opposite side had a non-painful joint with disc displacement without reduction (DDwoR). The subjects and controls were different individuals and only a single joint was used for each. Pain and dysfunction were evaluated by visual analogue scale. Bilateral proton density and T2 weighted images of the TMJs of the 31 subjects were analysed for fluid and condyle bony changes as well as disc position. The amount of fluid, identified as an area of high signal intensity in the region of the upper and lower joint spaces, was characterized as none, minimal, moderate or marked. Arthrocentesis was performed both for synovial fluid analysis of total protein concentration and the treatment of the joints with DDwoR. Total protein concentration was measured by using protein dye binding on spectrophotometry. All patients experienced a significant (P<0.01) increase in maximal mouth opening immediately post-arthrocentesis. In the study group, the disc was displaced most frequently in an anteriormedial direction (75%) and deformation of disc form was seen in 13 joints. Condylar bony changes were seen in 27% of joints in the control group and in 81% of joints in the study group. A statistically significant association was found between joints with disc displacement, disc form and condylar bony changes (P<0.05). In the control group, only one joint, which had an osteophyte, showed joint effusion (JE) with moderate fluid. In the study group, only four joints had no fluid (25%). JE was found in 10 (63%) joints with disc displacement on anteromedial direction, in 10 (63%) joints with disc deformation and in 10 (63%) joints with osteophytes and erosion. Mean total protein concentration was 16.87+/-7.9 (range 7.4-34.1 mg dl-1) in control joints, 55.08+/-35.16 (range 21.5-153.9 mg dl-1) in study joints. There were significant differences in the mean total protein concentration between the control and study groups (P<0.01). Significant positive correlation was found between the total protein concentration and JE (r=0.65, P<0.01). No significant correlation was found between the level of pain and dysfunction and JE and total protein concentration in either control or study groups (P>0.05). Pain in the TMJ was not related to MR findings of effusion in internal derangement and synovial fluid aspirate findings of total protein concentration. However, total protein concentration was related to the amount of JE in DDwoR joints and painful joints were more likely to demonstrate the JE.

Synovitis and soft tissue impingement of the ankle: assessment with enhanced three-dimensional FSPGR MR imaging.

To assess soft tissue impingement as well as synovitis of the ankle associated with trauma by using contrast-enhanced (CE), fat-suppressed, three-dimensional, fast gradient-recalled acquisition in the steady state with radiofrequency spoiling (FSPGR) magnetic resonance (MR) imaging. A total of 36 patients who had had chronic ankle pain associated with a traumatic injury undertook fat-suppressed CE three-dimensional FSPGR MR imaging and then arthroscopy of the ankle. The ankle joint was divided into four compartments by anatomic details: the anterolateral gutter, anteromedial gutter, anterior recess, and posterior recess. Synovial enhancement was graded as follows: grade I, no enhancement; grade II, linear enhancement; grade III, focal nodular enhancement; and grade IV, irregular nodular enhancement. MR grading of the synovial enhancement (synovitis, grade III or IV; soft tissue impingement, grade III or IV with its intrusion from the capsular reflection) was compared with arthroscopic findings. A control study of twenty asymptomatic ankles was done for determining enhancement. Arthroscopy confirmed synovitis in 47 compartments of 27 patients. Of the 27 patients, 15 revealed soft tissue impingement in 17 compartments. For the assessment of synovitis, fat-suppressed CE three-dimensional FSPGR MR imaging had an accuracy of 72.9%, sensitivity of 91.5%, and specificity of 63.9%; whereas for that of soft tissue impingement it had an accuracy of 94.4%, sensitivity of 76.5%, and specificity of 96.9%. All of the asymptomatic subjects showed grade I (81%) or II (19%) synovial enhancement. Fat-suppressed CE three-dimensional FSPGR MR imaging was sensitive for the evaluation of synovitis of the ankle associated with trauma, whereas it was specific for soft tissue impingement evaluation.

Dynamic MR imaging and stress testing in glenohumeral instability: Comparison with normal shoulders and clinical/surgical findings

Our objectives were to test the hypotheses that: 1) during shoulder motion, glenohumeral alignment differs between asymptomatic shoulders and those with symptomatic instability; 2) during magnetic resonance (MR)-monitored physical exam or stress testing, glenohumeral alignment differs between asymptomatic shoulders and those with instability; and 3) glenohumeral translation during MR stress testing correlates with findings of shoulder instability by clinical exam and exam under anesthesia (EUA). Using an open-configuration 0.5 T MR imaging (MRI) system, we studied symptomatic shoulders in 11 subjects and compared them to their contralateral asymptomatic shoulders. Each shoulder was studied during abduction/adduction and internal/external rotation to determine the humeral head position on the glenoid. An examiner also performed the MR stress test on each shoulder by applying manual force on the humeral head during imaging. All shoulders were assigned an instability grade from the MR stress test, and this grade was correlated with: 1) clinical exam grade assigned during preoperative assessment by an orthopedic surgeon and 2) intraoperative instability grade by EUA immediately preceding arthroscopy. With dynamic abduction and internal/external rotation, the humeral head remained centered on the glenoid in 9 of 11 shoulders, but in two subjects there were dramatic demonstrations of subluxation. With stress testing, a trend toward more joint laxity was demonstrated in symptomatic than in asymptomatic joints (P = 0.11). MR grading of instability correlated directly with clinical grading in six cases and underestimated the degree of instability relative to clinical exam in the other cases. MR instability grading systematically underestimated instability compared with EUA in 7 of the 10 cases that underwent surgical repair. We concluded that dynamic MR evaluation of glenohumeral alignment did not demonstrate abnormalities in symptomatic shoulders in 8 of 10 patients, whereas 2 patients showed dramatic findings of subluxation. Manual stress testing during dynamic MR examination showed a strong correlation with clinical instability grading. Dynamic shoulder MR examination during stress testing could, with further validation, become a useful adjunct to shoulder instability evaluations. J. Magn. Reson. Imaging 2001;13:748-756.

Hepatic iron deposition on MR imaging in patients with chronic liver disease: correlation with serial serum ferritin concentration.

To evaluate the relationship between magnetic resonance (MR) imaging grading of iron deposition and serial serum ferritin concentration in patients with chronic viral liver diseases. In 80 patients with viral hepatitis and cirrhosis, MR images including T2*-weighted gradient echo images (echo time > or = 6.5 ms) were reviewed. The grades of parenchymal iron deposition and iron-containing nodules in the liver and spleen and the liver-to-muscle and spleen-to-muscle signal intensity ratios were compared with the most recent, the mean, the lowest, and the highest values from all available serum ferritin levels. The serum ferritin concentration was significantly correlated with the grades of iron deposition in liver and spleen and with the grades of iron-containing nodules seen on MR images (p < 0.05). Liver-to-muscle signal intensity ratio was weakly correlated with the ferritin concentrations. Among categories of ferritin concentration, correlation with MR grades was highest for mean ferritin concentration (r = 0.487, p < 0.001). MR imaging grades of hepatic iron and siderotic nodules correlate with serum ferritin, especially with the mean levels.

Medial collateral ligament injuries: evaluation of multiple signs, prevalence and location of associated bone bruises, and assessment with MR imaging.

To investigate the multiple signs of medial collateral ligament (MCL) sprains, including the location and prevalence of associated bone bruises, and evaluate the accuracy of the criteria proposed for magnetic resonance (MR) imaging in grading these sprains. MR images were evaluated for signs of MCL injury in 76 patients with MCL sprains and 25 asymptomatic volunteers. These signs were then correlated with standards used to determine MCL injury at clinical evaluation. The grade of MCL injury as determined with MR imaging criteria was compared with clinical findings. All signs demonstrated little interobserver variability and were specific. The most sensitive signs were fascial edema and loss of demarcation from adjacent fat. This MR imaging grading system was inaccurate for classification of grade 3 MCL tears and was only questionably accurate for grades 1 and 2. Multiple signs of MCL sprains on MR images have varying sensitivities. MR grading systems may not be accurate for classification of MCL injuries.