Assessment of patellar cartilage cross-sectional area in patients with lower grade chondromalacia patella.

Chondromalacia patella (CMP) is abnormal softening of the cartilage of the underside the patella. It is a cause of anterior knee pain. Previous study has demonstrated that the patellar cartilage hypertrophy is correlated with early signs of CMP (Grade 1 or 2). However, no studies have investigated the clinical cutoff value of patella cartilage hypertrophy. Thus, we devised the patellar cartilage cross-sectional area (PCCSA) as a new predictive parameter for diagnosing the CMP. The purpose of this research was to compare MR measured PCCSA between CMP patients and gender matched healthy controls. The PCCSA samples were collected from 50 patients with CMP, and from 50 healthy controls who underwent knee MRI with no evidence of CMP. The T2-weighted turbo spin echo transverse MRI images were acquired. We measured the PCCSA on MRI using a PACS system. The PCCSA was measured on the axial angled sections through the whole images by drawing outlines. The average PCCSA was 104.28 ±â€…23.28 mm2 in the healthy controls and 134.09 ±â€…26.55 mm2 in the CMP group. CMP patients had significantly higher PCCSA (P < .001). Regarding the validity of PCCSA as predictors of CMP, Receiver Operating Characteristic curve analysis showed that the best cutoff point for the PCCSA was 116.24 mm2, with 72.0% sensitivity, 72.0% specificity, and the area under curve (AUC) of 0.79 (0.71-0.88). The PCCSA is a sensitive measurement parameter to predict low grade CMP. Thus, to evaluate CMP patients, the treating physician carefully inspect the PCCSA.

Toward New Assessment of Knee Cartilage Degeneration.

OBJECTIVE: Assessment of human joint cartilage is a crucial tool to detect and diagnose pathological conditions. This exploratory study developed a workflow for 3D modeling of cartilage and bone based on multimodal imaging. New evaluation metrics were created and, a unique set of data was gathered from healthy controls and patients with clinically evaluated degeneration or trauma. DESIGN: We present a novel methodology to evaluate knee bone and cartilage based on features extracted from magnetic resonance imaging (MRI) and computed tomography (CT) data. We developed patient specific 3D models of the tibial, femoral, and patellar bones and cartilages. Forty-seven subjects with a history of degenerative disease, traumatic events, or no symptoms or trauma (control group) were recruited in this study. Ninety-six different measurements were extracted from each knee, 78 2D and 18 3D measurements. We compare the sensitivity of different metrics to classify the cartilage condition and evaluate degeneration. RESULTS: Selected features extracted show significant difference between the 3 groups. We created a cumulative index of bone properties that demonstrated the importance of bone condition to assess cartilage quality, obtaining the greatest sensitivity on femur within medial and femoropatellar compartments. We were able to classify degeneration with a maximum recall value of 95.9 where feature importance analysis showed a significant contribution of the 3D parameters. CONCLUSION: The present work demonstrates the potential for improving sensitivity in cartilage assessment. Indeed, current trends in cartilage research point toward improving treatments and therefore our contribution is a first step toward sensitive and personalized evaluation of cartilage condition.

Sonographic assessment of cartilage damage at the metacarpal head in rheumatoid arthritis: qualitative versus quantitative methods.

OBJECTIVE: To test the validity of the OMERACT semi-quantitative score by comparing with a quantitative method in the US assessment of hyaline cartilage at the metacarpal head (MH) in patients with RA and healthy controls (HCs). METHODS: The hyaline cartilage from the second to fifth MHs of both hands was scanned. Hyaline cartilage was scored semi-quantitatively and quantitatively by measuring cartilage thickness and comparing with reference values. In RA patients, radiographic joint space narrowing (JSN) was scored on the same joints using the Simple Erosion Narrowing Score (SENS). RESULTS: A total of 408 MHs in 51 RA patients and 320 MHs in 40 HSs were evaluated. The OMERACT semi-quantitative score was quicker to perform than the quantitative method [6.0 min (s.d. 0.5) vs 8.0 (1.5); P < 0.01]. A significant correlation between the US scores (R = 0.68) and between the US scores and the JSN-SENS (R = 0.61 and R = 0.63 for the semi-quantitative and quantitative method, respectively) was found. The frequency of cartilage abnormalities was similar between the two US methods in RA patients (58.8% and 51.0% of RA patients for the semi-quantitative and quantitative method, respectively; P = 0.46), while the former revealed more abnormalities in HCs (27.5% and 7.5% of HCs; P = 0.02). CONCLUSION: The higher feasibility of the OMERACT semi-quantitative score suggests its use as a first-choice method in the evaluation of cartilage damage. However, despite its limits, the quantitative assessment of HCs, providing patient-tailored information with age- and sex-corrected cut-off values, may represent a valid supplement for optimizing the evaluation of cartilage damage in selected cases.

Synthetic MRI is not yet ready for morphologic and functional assessment of patellar cartilage at 1.5Tesla.

PURPOSE: The purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5T magnetic resonance imaging (MRI). METHOD: The MRI examinations of the knee obtained at 1.5T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45±17.7 (SD) years (range: 18-88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC). RESULTS: In vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5±2.3 (SD) ms and 58.8±2.6 (SD) ms, respectively (P=0.414) and 6% lower than the expected experimental values (P=0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8±4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P=0.009) and lower chondropathy scores (3.7±4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC>0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2±3.8 [SD] ms; range: 29-46ms) relative to conventional T2 maps (31.8±4.1 [SD] ms; range: 26-49ms) (P<0.0001). CONCLUSION: Despite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences.

Quantitative articular cartilage sub-surface defect assessment using optical coherence tomography: An in-vitro study.

Assessment of structural cartilage damage is of high scientific and clinical interest. Optical Coherence Tomography (OCT) is a light-based cross-sectional imaging modality that allows the real-time assessment of articular cartilage at near-histological resolution. Algorithm routines for the detection, parameterization and quantification of sub-surface defects as assessed by OCT were implemented and validated in this study. Standard defects of 0.9mm, 1.1mm and 1.3mm diameter were created in the sub-surface regions of macroscopically intact human articular cartilage samples (n=60 defects of variable sizes in n=20 samples). Subsequently, samples were scanned by 3D OCT and defect size, height, width and distance to the surface were determined based on the algorithm and related to manual measurements. Histology served as the standard-of-reference. Statistical analysis included one-way ANOVA's and Tukey's post-hoc test. All defects were correctly identified by the algorithm, while five structural tissue inhomogeneities were erroneously marked as defects (sensitivity 100%, specificity: 92.3%). Inter-modality analysis revealed no significant differences in terms of defect area, height or width within the different defect sizes, while the distance to the surface was significantly different. The comprehensive algorithm-based characterization of cartilage defects is consistent and reliable and allows their more objective evaluation. Given further research in this field, OCT and OCT-based quantitative measures may become clinically useful in the arthroscopic detection and evaluation of sub-surface cartilage defects.

Quantitative Assessment of Degenerative Cartilage and Subchondral Bony Lesions in a Preserved Cadaveric Knee: Propagation-Based Phase-Contrast CT Versus Conventional MRI and CT.

OBJECTIVE: The aim of this study was to quantitatively assess hyaline cartilage and subchondral bone conditions in a fully preserved cadaveric human knee joint using high-resolution x-ray propagation-based phase-contrast imaging (PBI) CT and to compare the performance of the new technique with conventional CT and MRI. MATERIALS AND METHODS: A cadaveric human knee was examined using an x-ray beam of 60 keV, a detector with a 90-mm2 FOV, and a pixel size of 46 × 46 µm2. PBI CT images were reconstructed with both the filtered back projection algorithm and the equally sloped tomography method. Conventional 3-T MRI and CT were also performed. Measurements of cartilage thickness, cartilage lesions, International Cartilage Repair Society scoring, and detection of subchondral bone changes were evaluated. Visual inspection of the specimen akin to arthroscopy was conducted and served as a standard of reference for lesion detection. RESULTS: Loss of cartilage height was visible on PBI CT and MRI. Quantification of cartilage thickness showed a strong correlation between the two modalities. Cartilage lesions appeared darker than the adjacent cartilage on PBI CT. PBI CT showed similar agreement to MRI for depicting cartilage substance defects or lesions compared with the visual inspection. The assessment of subchondral bone cysts showed moderate to strong agreement between PBI CT and CT. CONCLUSION: In contrast to the standard clinical methods of MRI and CT, PBI CT is able to simultaneously depict cartilage and bony changes at high resolution. Though still an experimental technique, PBI CT is a promising high-resolution imaging method to evaluate comprehensive changes of osteoarthritic disease in a clinical setting.

The validity and accuracy of MRI arthrogram in the assessment of painful articular disorders of the hip.

The assessment of a patient with chronic hip pain can be challenging. The differential diagnosis of intra-articular pathology causing hip pain can be diverse. These includes conditions such as osteoarthritis, fracture, and avascular necrosis, synovitis, loose bodies, labral tears, articular pathology and, femoro-acetabular impingement. Magnetic resonance imaging (MRI) arthrography of the hip has been widely used now for diagnosis of articular pathology of the hip. A retrospective analysis of 113 patients who had MRI arthrogram and who underwent hip arthroscopy was included in the study. The MRI arthrogram was performed using gadolinium injection and reported by a single radiologist. The findings were then compared to that found on arthroscopy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and 95% confidence interval were calculated for each pathology. Labral tear-sensitivity 84% (74.3-90.5), specificity 64% (40.7-82.8), PPV 91% (82.1-95.8), NPV 48% (29.5-67.5), accuracy 80%. Delamination -sensitivity 7% (0.8-22.1), specificity 98% (91.6-99.7), PPV 50% (6.8-93.2), NPV 74% (65.1-82.2) and accuracy 39%. Chondral changes-sensitivity 25% (13.3-38.9), specificity 83% (71.3-91.1), PPV 52% (30.6-73.2), NPV 59% (48.0-69.2) and accuracy 58%. Femoro-acetabular impingement (CAM deformity)-sensitivity 34% (19.6-51.4), specificity 83% (72.2-90.4), PPV 50% (29.9-70.1), NPV 71% (60.6-80.5) and accuracy 66%. Synovitis-sensitivity 11% (2.3-28.2), specificity 99% (93.6-100), PPV 75% (19.4-99.4), NPV 77% (68.1-84.6) and accuracy 77%. Our study conclusions are MRI arthrogram is a useful investigation tool in detecting labral tears, it is also helpful in the diagnosis of femoro-acetabular impingement. However, when it comes to the diagnosis of chondral changes, defects and cartilage delamination, the sensitivity and accuracy are low.

Qualitative and quantitative assessment of cartilage degeneration using full-field optical coherence tomography ex vivo.

OBJECTIVE: The purpose of this study was to investigate the ability of full-field optical coherence tomography (FFOCT) to qualitatively and quantitatively evaluate cartilage degeneration using the qualitative evaluation of histology sections as the reference. DESIGN: Thirty-three human knee cartilage samples of variable degeneration were included in the study. A closely matching histology and FFOCT image was acquired for each sample. The cartilage degeneration was qualitatively evaluated by assigning a grade to each histology and FFOCT image. The relevance of the performed grading was assessed by calculating the intra- and inter-observer reproducibility and calculating the concordance between the histology and FFOCT grades. A near-automatic algorithm was developed to quantitatively characterize the cartilage surface in each image. The correlation between the quantitative results and the reference qualitative histology was calculated. RESULTS: An almost perfect agreement was achieved for both the intra- and inter-reproducibility of the histology and FFOCT qualitative grading (κ ≥ 0.91). A high and statistically significant level of agreement was measured between the histology and FFOCT grades (W = 0.95, P < 0.05). Strong and statistically significant correlations were measured between the quantitative results and the reference qualitative histology grades (ρ ≥ 0.75, P < 0.05). CONCLUSIONS: We have demonstrated that FFOCT is an alternative approach to conventional optical coherence tomography (OCT) that is as well adapted for the qualitative and quantitative assessment of human cartilage as the reference gold standard - histology. This study constitutes the first promising results towards developing a new diagnostic tool in the field of osteoarthritis.

Five-minute knee MRI for simultaneous morphometry and T2 relaxometry of cartilage and meniscus and for semiquantitative radiological assessment using double-echo in steady-state at 3T.

BACKGROUND: Biomarkers for assessing osteoarthritis activity necessitate multiple MRI sequences with long acquisition times. PURPOSE: To perform 5-minute simultaneous morphometry (thickness/volume measurements) and T2 relaxometry of both cartilage and meniscus, and semiquantitative MRI Osteoarthritis Knee Scoring (MOAKS). STUDY TYPE: Prospective. SUBJECTS: Fifteen healthy volunteers for morphometry and T2 measurements, and 15 patients (five each Kellgren-Lawrence grades 0/2/3) for MOAKS assessment. FIELD STRENGTH/SEQUENCE: A 5-minute double-echo steady-state (DESS) sequence was evaluated for generating quantitative and semiquantitative osteoarthritis biomarkers at 3T. ASSESSMENT: Flip angle simulations evaluated tissue signals and sensitivity of T2 measurements. Morphometry and T2 reproducibility was compared against morphometry-optimized and relaxometry-optimized sequences. Repeatability was assessed by scanning five volunteers twice. MOAKS reproducibility was compared to MOAKS derived from a clinical knee MRI protocol by two readers. STATISTICAL TESTS: Coefficients of variation (CVs), concordance confidence intervals (CCI), and Wilcoxon signed-rank tests compared morphometry and relaxometry measurements with their reference standards. DESS MOAKS positive percent agreement (PPA), negative percentage agreement (NPA), and interreader agreement was calculated using the clinical protocol as a reference. Biomarker variations between Kellgren-Lawrence groups were evaluated using Wilcoxon rank-sum tests. RESULTS: Cartilage thickness (P = 0.65), cartilage T2 (P = 0.69), and meniscus T2 (P = 0.06) did not significantly differ from their reference standard (with a 20° DESS flip angle). DESS slightly overestimated meniscus volume (P < 0.001). Accuracy and repeatability CVs were <3.3%, except the meniscus T2 accuracy (7.6%). DESS MOAKS had substantial interreader agreement and high PPA/NPA values of 87%/90%. Bone marrow lesions and menisci had slightly lower PPAs. Cartilage and meniscus T2 , and MOAKS (cartilage surface area, osteophytes, cysts, and total score) was higher in Kellgren-Lawrence groups 2 and 3 than group 0 (P < 0.05). DATA CONCLUSION: The 5-minute DESS sequence permits MOAKS assessment for a majority of tissues, along with repeatable and reproducible simultaneous cartilage and meniscus T2 relaxometry and morphometry measurements. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1328-1341.

Routine clinical knee MR reports: comparison of diagnostic performance at 1.5 T and 3.0 T for assessment of the articular cartilage.

OBJECTIVE: Accurate assessment of knee articular cartilage is clinically important. Although 3.0 Tesla (T) MRI is reported to offer improved diagnostic performance, literature regarding the clinical impact of MRI field strength is lacking. The purpose of this study is to compare the diagnostic performance of clinical MRI reports for assessment of cartilage at 1.5 and 3.0 T in comparison to arthroscopy. MATERIALS AND METHODS: This IRB-approved retrospective study consisted of 300 consecutive knees in 297 patients who had routine clinical MRI and arthroscopy. Descriptions of cartilage from MRI reports of 165 knees at 1.5 T and 135 at 3.0 T were compared with arthroscopy. The sensitivity, specificity, percent of articular surfaces graded concordantly, and percent of articular surfaces graded within one grade of the arthroscopic grading were calculated for each articular surface at 1.5 and 3.0 T. Agreement between MRI and arthroscopy was calculated with the weighted-kappa statistic. Significance testing was performed utilizing the z-test after bootstrapping to obtain the standard error. RESULTS AND CONCLUSIONS: The sensitivity, specificity, percent of articular surfaces graded concordantly, and percent of articular surfaces graded within one grade were 61.4%, 82.7%, 62.2%, and 77.5% at 1.5 T and 61.8%, 80.6%, 59.5%, and 75.6% at 3.0 T, respectively. The weighted kappa statistic was 0.56 at 1.5 T and 0.55 at 3.0 T. There was no statistically significant difference in any of these parameters between 1.5 and 3.0 T. Factors potentially contributing to the lack of diagnostic advantage of 3.0 T MRI are discussed.

Prestructural cartilage assessment using MRI.

Cartilage loss is irreversible, and to date, no effective pharmacotherapies are available to protect or regenerate cartilage. Quantitative prestructural/compositional MR imaging techniques have been developed to characterize the cartilage matrix quality at a stage where abnormal findings are early and potentially reversible, allowing intervention to halt disease progression. The goal of this article is to critically review currently available technologies, present the basic concept behind these techniques, but also to investigate their suitability as imaging biomarkers including their validity, reproducibility, risk prediction and monitoring of therapy. Moreover, we highlighted important clinical applications. This review article focuses on the currently most relevant and clinically applicable technologies, such as T2 mapping, T2*, T1ρ, delayed gadolinium enhanced MRI of cartilage (dGEMRIC), sodium imaging and glycosaminoglycan chemical exchange saturation transfer (gagCEST). To date, most information is available for T2 and T1ρ mapping. dGEMRIC has also been used in multiple clinical studies, although it requires Gd contrast administration. Sodium imaging and gagCEST are promising technologies but are dependent on high field strength and sophisticated software and hardware. LEVEL OF EVIDENCE: 5 J. Magn. Reson. Imaging 2017;45:949-965.

Microfracture for chondral defects: assessment of the variability of surgical technique in cadavers.

PURPOSE: The purpose of this study was to assess the variability of the microfracture technique when performed by experienced knee arthroscopy surgeons. METHOD: Four surgeons were each asked to perform microfracture on six preformed cartilage defects in fresh human cadaveric knees. Surgeons were instructed on penetration depth, inter-hole distance, and to place the holes perpendicular to the subchondral surface. Micro-computed tomography was used to calculate depth error, inter-hole distance error, and deviation of penetration angles from the perpendicular. RESULTS: All surgeons misjudged depth and inter-hole distance, tending to make microfracture holes too deep (depth error 1.1 mm ± 1.9) and too close together (inter-hole distance error: -0.8 mm ± 0.4). Fifty-one per cent of holes were angled more than 10° from the perpendicular (range 2.6°-19.8°). Both depth and distance errors were significantly lower in the trochlear groove than on the femoral condyle (p < 0.05). Surface shearing was associated with both penetration depth >4 mm and angles >20°. Inter-hole infraction occurred in holes closer than 2.5 mm to each other. CONCLUSION: Even experienced knee arthroscopy surgeons demonstrate inconsistency in surgical technique when performing microfracture. While further research will be required to demonstrate that these variations in surgical technique are associated with poorer clinical outcomes after microfracture, surgeons should attempt to minimizing such variations in order to prevent surface shearing and inter-hole infraction.

Quantitative Ultrasound Assessment of Cartilage Degeneration in Ovariectomized Rats with Low Estrogen Levels.

The aim of this study was to assess quantitatively the site-specific degeneration of articular cartilage in ovariectomized rats with low estrogen levels using a high-frequency ultrasound system. Fourteen female Sprague-Dawley rats were randomly divided into two groups (n = 7 per group): a sham group in which only the peri-ovarian fatty tissue was exteriorized and an ovariectomized group that underwent bilateral ovariectomy to create a menopause model with low estrogen levels. All animals were sacrificed at the end of the third week after ovariectomy. Hindlimbs were harvested. The articular cartilage from five anatomic sites (i.e., femoral caput [FC], medial femoral condyle [MFC], lateral femoral condyle [LFC], medial tibial plateau [MTP] and lateral tibial plateau [LTP]) was examined with ultrasound. Four parameters were extracted from the ultrasound radiofrequency data: reflection coefficient of the cartilage surface (RC1), reflection coefficient of the cartilage-bone interface (RC2), ultrasound roughness index (URI) and thickness of the cartilage tissue. The results indicated significant (p < 0.05) site dependence for cartilage thickness, URI and RC1 in the sham group. The 3-wk post-menopause ovariectomized rats exhibited significant increases (p < 0.05) in the URI at the LFC, MTP and LTP; significant decreases (p < 0.05) in RC1 at the FC, LFC and MTP; and significant decreases (p < 0.05) in cartilage thickness at the MFC, LFC, MTP and LTP. These results of this study suggest that post-menopausal estrogen reduction induces morphologic and acoustic alterations in the articular cartilage of the hip and knee joints in ovariectomized rats.

[Imaging assessment of bone and cartilage destruction in rheumatoid arthritis].

Rheumatoid arthritis (RA) is characterized by synovitis and subsequent joint destruction involving bone and cartilage. Recent therapeutic development have improved outcomes including disease activity and structural progression in RA, and standardized procedures of imaging assessment including modified total Sharp score (mTSS) have contributed largely for the development of therapeutic strategy. In addition, ultrasonography and MRI of joints have been recently emerging as novel imaging methods for RA. Here, we review current imaging assessments of bone and cartilage destruction in RA.

Visualization of small lesions in rat cartilage by means of laboratory-based x-ray phase contrast imaging.

Being able to quantitatively assess articular cartilage in three-dimensions (3D) in small rodent animal models, with a simple laboratory set-up, would prove extremely important for the development of pre-clinical research focusing on cartilage pathologies such as osteoarthritis (OA). These models are becoming essential tools for the development of new drugs for OA, a disease affecting up to 1/3 of the population older than 50 years for which there is no cure except prosthetic surgery. However, due to limitations in imaging technology, high-throughput 3D structural imaging has not been achievable in small rodent models, thereby limiting their translational potential and their efficiency as research tools. We show that a simple laboratory system based on coded-aperture x-ray phase contrast imaging (CAXPCi) can correctly visualize the cartilage layer in slices of an excised rat tibia imaged both in air and in saline solution. Moreover, we show that small, surgically induced lesions are also correctly detected by the CAXPCi system, and we support this finding with histopathology examination. Following these successful proof-of-concept results in rat cartilage, we expect that an upgrade of the system to higher resolutions (currently underway) will enable extending the method to the imaging of mouse cartilage as well. From a technological standpoint, by showing the capability of the system to detect cartilage also in water, we demonstrate phase sensitivity comparable to other lab-based phase methods (e.g. grating interferometry). In conclusion, CAXPCi holds a strong potential for being adopted as a routine laboratory tool for non-destructive, high throughput assessment of 3D structural changes in murine articular cartilage, with a possible impact in the field similar to the revolution that conventional microCT brought into bone research.

Interobserver reliability of ultrasonography in the assessment of cartilage damage in rheumatoid arthritis.

OBJECTIVES: To evaluate the interobserver reliability of ultrasonography (US) in the assessment of cartilage damage at metacarpophalangeal (MCP) joint level in patients with rheumatoid arthritis (RA). METHODS: US examinations were performed on 80 MCP joints of 20 patients with RA using a MyLab70 XVG (Esaote Biomedica, Genoa, Italy), equipped with a broadband linear probe (6-18 MHz). For each patient, second and third MCP joints of both hands were examined independently on the same day by two rheumatologists (an experienced musculoskeletal sonographer and an investigator with limited US training). A multiplanar scanning technique on dorsal, lateral and volar aspects of the MCP joints was adopted. All US pathological findings were documented on at least two perpendicular scanning planes. Each joint was assessed by quadrant for the presence or absence of cartilage damage. Cartilage damage was also scored per quadrant on a five-grade semiquantitative scoring system on which investigators reached a consensus prior to the study. RESULTS: Exact agreement between investigators was found in 173 out of 200 quadrants (86.5%) with regard to presence or absence of cartilage damage. Percentages of exact agreement for cartilage damage semiquantitative assessment at dorsal, lateral and volar quadrants were 72.5%, 52.5% and 85%, respectively, while unweighted κ values were 0.561, 0.366 and 0.766, respectively. CONCLUSIONS: The present study demonstrated moderate to good interobserver reproducibility of a semiquantitative scoring system based on qualitative morphological changes for cartilage damage at MCP joint level in patients with RA.

Knee MR-arthrography in assessment of meniscal and chondral lesions.

INTRODUCTION: No study, so far in France, has investigated the diagnosis value of knee MR-arthrography since the recent approval of intra-articular gadolinium use, by this country's healthcare authorities. This study objective is to verify the MR-arthrography superiority on conventional knee MRI, in meniscus and cartilage knee lesions diagnosing accuracy both in regard to sensitivity and specificity. HYPOTHESIS: MR-arthrography, represents in some pathologic situations, a more accurate source of information than conventional MRI. MATERIALS AND METHODS: Over a 27 months period, 25 patients, scheduled to undergo a knee arthroscopy volunteered, after having been fully informed of the possible interest and risk of the MR-arthrography examination, to participate in this study. Twenty-one of them were finally included since in four cases the surgical indication was not confirmed. The group consisted of 15 males and six females with an average age of 35.7 years. All of them consecutively underwent conventional MRI, MR-arthrography finally followed by arthroscopy. The MRI and MR-arthrograms results were compared to the arthroscopy findings using the nonparametric Kappa test. RESULTS: To diagnose meniscal tears, statistical agreement measure for MRI with arthroscopy was good (K=0.69) but not as good as the MR-arthrography/arthroscopy agreement which, by itself was excellent (K=0.84). As a diagnosis tool, the sensitivity and specificity of MR-arthrography (respectively 100 and 89.6%) were much higher than the corresponding values observed in conventional MRI (92.3 and 82.8%, respectively) which nonetheless remain satisfactory. The meniscal tears characterization seemed to be better interpreted using MR-arthrography. As far as the chondral lesions in this series, they were predominantly located on the patellar surface and in the medial femorotibial compartment. For diagnosing the latter, the MRI/arthroscopy agreement was good (K=0.70) but not as good as the MR-arthrography/arthroscopy agreement (K=0.805) which can be rated excellent. The detection sensitivity thus increased by 10% with gadolinium intra-articular injection. However, assessment accuracy of the lesions depth was mediocre, with frequent errors for the intermediary stages. DISCUSSION: Intra-articular gadolinium injection improved MRI performances for numerous reasons: filling the joint, reinforcing the synovial fluid signal, and enhancing anatomic structures contrast on the T1-weighted sequences images. In this study, MR-arthrography appeared to be superior to conventional MRI in meniscal and cartilaginous lesions diagnosis, confirming the results previously obtained in other countries. In light of these results and other data from the literature, MR-arthrography can be indicated as an alternative to CT-arthrography in various clinical situations: detection of recurrent tears on operated menisci, search for cartilaginous lesions or foreign bodies in the joint space, and preoperative assessment before chondral repair procedures. However, conventional MRI remains the reference examination for studying cartilage, because the low resolution of MR-arthrography limits its performances in quantitative assessment of lesions depth.

Reliability of diffraction enhanced imaging for assessment of cartilage lesions, ex vivo.

OBJECTIVE: The assessment of articular cartilage integrity is of value for the detection of early degenerative joint disease in both the clinical and the research settings. It was the purpose of this study to determine the accuracy and reliability of identifying articular cartilage defects through Diffraction Enhanced Imaging (DEI), a high contrast radiographic imaging technique. DEI provides two new sources of image contrast to radiography: refraction and scatter rejection, besides the absorption of conventional radiography. DESIGN: Cadaveric tali were DEI imaged in the anterior-posterior position at the National Synchrotron Light Source. Two independent observers provided gross score evaluations (on a five point scale) of the trochlear surfaces. The DEI image of each trochlear surface was then graded (on a five point scale) by two additional independent observers who were blinded with regard to the gross evaluation of the articular surfaces. Inter-observer agreement for DEI grades was assessed with the weighted kappa statistic. Correlation of diffraction enhanced image score to the gross score was assessed with Spearman correlation coefficient. RESULTS: The defects of articular cartilage of talar trochleae could be visualized through DEI. The Spearman correlation of gross grades with DEI grades on the 165 talar regions for observers 1 and 2 were 0.91 and 0.91, respectively. The overall weighted kappa value for inter-observer agreement was 0.93, thus considered high agreement. CONCLUSIONS: DEI is accurate and reliable for detection of articular cartilage defects ex vivo. Even early stages of degeneration of cartilage can be visualized with this high contrast technique. Future studies will focus on the application of DEI to the identification of such lesions in vivo.

Comparison of patella cartilage volume and radiography in the assessment of longitudinal joint change at the patellofemoral joint.

OBJECTIVE: To compare radiological assessment of the patellofemoral (PF) joint and cartilage volume as measured by magnetic resonance imaging (MRI) in a longitudinal study. METHODS: One hundred and two subjects with osteoarthritis (OA) had baseline and followup skyline and lateral radiographs and MRI of the same knee. Duration of followup was 1.94 +/- 0.23 years. Mid-patella joint space and narrowest joint space were measured on lateral PF radiographs. Minimum joint space in the lateral and medial facets was measured on skyline radiographs. Rate of progression of PF joint OA was measured quantitatively at each site. Patella cartilage volume was measured from the MRI. The rate of change in each radiographic measure was compared to the rate of change in patella cartilage volume. RESULTS: The average loss of patella cartilage was 133 +/- 143 microm(3)/yr (4.4%). The loss of joint space over the same period on lateral radiographs was 0.7 +/- 2.6 mm at the narrowest joint space and 0.2 +/- 3.8 mm at the mid-patella joint space. On the skyline radiographs, the loss of joint space at the medial facet was 0.4 +/- 3.9 mm and 0.2 +/- 3.4 mm at the lateral facet. Only change in narrowest joint space on the lateral PF radiographs correlated with change in patella cartilage volume (R = 0.22, p = 0.03). CONCLUSION: Our data suggest that narrowest joint space measured on lateral PF radiographs correlates best with loss of patella cartilage. Further work will be needed to determine how different radiological measures of the PF joint relate to the disease process in OA.

Ultrasonography and articular cartilage defects in the knee: an in vitro evaluation of the accuracy of cartilage thickness and defect size assessment.

The purpose of this cadaver study was to test the accuracy of ultrasonography in measuring cartilage thickness, and the extent and depth of induced cartilage defects on the medial and lateral femoral condyles of the knee in a clinically relevant setting. With the knees maximally flexed, cartilage thickness was measured at 24 marked sites in four knees with a 10 MHz probe. The areas of measurement were then excised and the thickness measured with a calliper gauge. In another seven cadaver knees, 21 cartilage defects were produced. The defect diameter varied from 4 to 8 mm. The depths of the defects were either a partial cartilage defect (grade 2), a defect to intact subchondral bone (grade 3), or a defect involving subchondral bone (grade 4) (classification by ICRS). The limits of agreement between ultrasonography and calliper gauge measurement for cartilage thickness were chi(diff)+/-2SD(diff)=0.0+/-0.4 mm. For cartilage defect diameter, the limits of agreement between ultrasonography and the slide ruler measurement were chi(diff)+/-2SD(diff)=-0.2+/-1.0 mm. For the depths of the lesions there was a 100% agreement between radiologist and actual lesion depth for the classification into International Cartilage Repair Society (ICRS) grades 2, 3, and 4. Our conclusion is that ultrasonography is capable of measuring accurately both cartilage thickness and the extent and depth of induced cartilage defects in a cadaver model.