Low-field MRI versus ultrasound: which is more sensitive in detecting inflammation and bone damage in MCP and MTP joints in mild or moderate rheumatoid arthritis?

OBJECTIVES

The aim of the present paper is to determine if the ultrasound of hands and feet is comparable to the MRI of the dominant hand to detect erosive disease and inflammation in mild or moderate rheumatoid arthritis (RA).

METHODS

Twenty-six patients (14 females; mean age, 48 years) with active mild or moderate RA (mean DAS28, 3.9; mean disease duration, 19 months) were examined clinically, by ultrasound and by gadolinium-enhanced low-field MRI at baseline, after 6 and 12 months (78 examinations). Radiographs from hands and forefeet were taken at baseline and after 12 months. MRI was performed at the clinically most active (dominant) hand or forefoot evaluating the MCP 1-5 or MTP 1-5 joints. Ultrasound examination additionally included all other 2nd, 5th MCP and 5th MTP joints.

RESULTS

MRI and ultrasound detected erosive disease in 67 and 56 of 78 examinations, respectively (p<0.01); radiography only in 8 of 52 examinations (p<0.001). MRI and ultrasound were equally sensitive to detect synovitis (in 64 and 66 examinations). Synovial power Doppler signals were present in 38 ultrasound examinations. Bone marrow oedema was present in 37 MRI examinations. Ultrasound was more sensitive than MRI to detect tenosynovitis (in 30 vs. 15 examinations; p=0.001).

CONCLUSIONS

MRI of the dominant hand and bilateral ultrasound of MCP and MTP joints are superior to x-ray to detect erosive disease in mild and moderate RA. MRI is slightly, but significantly more sensitive than ultrasound for erosive disease, while ultrasound is more sensitive to detect tenosynovitis. Ultrasound and MRI are comparably sensitive to detect synovitis.

Synovitis and bone inflammation in early rheumatoid arthritis: high-resolution multi-pinhole SPECT versus MRI

PURPOSE

We aimed to assess the relationship between bone inflammation in multi-pinhole single-photon emission computed tomography (MPH-SPECT) and synovitis detected by magnetic resonance imaging (MRI) in early rheumatoid arthritis patients.

MATERIALS AND METHODS

MPH-SPECT with technetium dicarboxypropanedisphosphonate (Tc-99mDPD) and 3 Tesla MRI were performed in 10 early rheumatoid arthritis patients. Eighty finger joint sites were assessed for increased osteoblastic activity using visual and region-of-interest (ROI) analysis. Presence of joint inflammation in MRI was investigated using the subscores of the rheumatoid arthritis MRI score.

RESULTS

Tc-99mDPD uptake was increased in 38 (47.5%) and 22 (27.5%) joint sites as determined by visual and ROI analysis, respectively. A total of 32 (84.2%) sites with increased bone metabolism showed a normal MRI bone signal. The MPH-SPECT uptake ratio was elevated only in the subgroup with severe synovitis (P < 0.001).

CONCLUSION

In early rheumatoid arthritis, molecular imaging with MPH-SPECT detects higher rates of inflammatory bone involvement compared to MRI. Our preliminary data suggest that osteitis is related to severe synovitis.

Utility of combined high-resolution bone SPECT and MRI for the identification of rheumatoid arthritis patients with high-risk for erosive progression

OBJECTIVES

To evaluate the utility of sequentially acquired, post hoc fused, magnetic resonance imaging (MRI) and multi-pinhole single photon emission computed tomography (MPH-SPECT) with technetium-99m-labeled disphosphonates (Tc99m-DPD) for the identification of finger joints with later erosive progression in early rheumatoid arthritis (ERA) patients.

METHODS

Ten consecutive ERA patients prospectively underwent MPH-SPECT and MRI of metacarpophalangeal (MCP) joints prior to and after 6 months methotrexate therapy. Tc99m-DPD uptake was measured at proximal and distal MCP sites using regional analysis. The course of joint pathologies was scored according to the Rheumatoid Arthritis MRI Score (RAMRIS) criteria.

RESULTS

The frequency of increased Tc99m-DPD uptake, synovitis and bone marrow edemadecreased under MTX therapy; but the number of bone erosions increased. Joints with progressive and new erosions on follow-up had a higher baseline Tc99m-DPD uptake (2.64 ± 1.23 vs. 1.43 ± 0.91) (p=0.02).

CONCLUSIONS

Joints with erosive progression are characterized by an early increased Tc99m-DPD uptake, even in absence of MRI bone pathologies. Tc99m-DPD MPH-SPECT might thus be of additional value to morphological MRI for the identification of RA patients with a high risk for erosive progression.

Molecular imaging of cartilage damage of finger joints in early rheumatoid arthritis with delayed gadolinium-enhanced magnetic resonance imaging

OBJECTIVE

To assess cartilage glycosaminoglycan content and cartilage thickness in the metacarpophalangeal (MCP) joints of patients with early rheumatoid arthritis (RA) and healthy volunteers.

METHODS

After review board approval and informed consent were obtained, 22 subjects were prospectively enrolled (9 patients with early RA [7 women and 2 men with a mean ± SD age of 49 ± 13 years; range 25-68 years] and 13 healthy volunteers [10 women and 3 men with a mean ± SD age of 51 ± 12 years; range 25-66 years). In a total of 44 MCP joints of the index and middle fingers, measurements of cartilage thickness and delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) index (T1 [msec]) were obtained using the variable flip-angle method and a 3T MR scanner. MRIs were evaluated for bone edema, erosions, and synovitis (using the RA MRI Scoring criteria). Student's t-test was used to test the significance of differences between groups.

RESULTS

The mean ± SD dGEMRIC index was 497 ± 86 msec in healthy volunteers and was significantly lower in the early RA group (421 ± 76 msec) (P = 0.042). There was no joint space narrowing seen on standard radiographs. No significant difference was found between cartilage thickness in patients with early RA and that in controls (index finger mean ± SD 1.27 ± 0.23 mm in RA patients versus 1.46 ± 0.34 mm in controls [P = 0.16] and middle finger 1.26 ± 0.23 mm in RA patients versus 0.97 ± 0.47 mm in controls [P = 0.10]). No significant correlation was noted between cartilage thickness and dGEMRIC index (R = 0.36, P = 0.88 in RA patients; R = 0.156, P = 0.445 in controls).

CONCLUSION

Our findings indicate that cartilage damage is present in the MCP joints of patients with early RA despite the absence of joint space narrowing on standard radiographs and MRI. Cartilage damage in RA can be imaged with dGEMRIC.

[Case-based interactive PACS learning: introduction of a new concept for radiological education of students]

PURPOSE

Medical curricula are currently being reformed in order to establish superordinated learning objectives, including, e.g., diagnostic, therapeutic and preventive competences. This requires a shifting from traditional teaching methods towards interactive and case-based teaching concepts. Conceptions, initial experiences and student evaluations of a novel radiological course Co-operative Learning In Clinical Radiology (CLICR) are presented in this article.

MATERIALS AND METHODS

A novel radiological teaching course (CLICR course), which combines different innovative teaching elements, was established and integrated into the medical curriculum. Radiological case vignettes were created for three clinical teaching modules. By using a PC with PACS (Picture Archiving and Communication System) access, web-based databases and the CASUS platform, a problem-oriented, case-based and independent way of learning was supported as an adjunct to the well established radiological courses and lectures. Student evaluations of the novel CLICR course and the radiological block course were compared.

RESULTS

Student evaluations of the novel CLICR course were significantly better compared to the conventional radiological block course. Of the participating students 52% gave the highest rating for the novel CLICR course concerning the endpoint overall satisfaction as compared to 3% of students for the conventional block course. The innovative interactive concept of the course and the opportunity to use a web-based database were favorably accepted by the students. Of the students 95% rated the novel course concept as a substantial gain for the medical curriculum and 95% also commented that interactive working with the PACS and a web-based database (82%) promoted learning and understanding.

CONCLUSION

Interactive, case-based teaching concepts such as the presented CLICR course are considered by both students and teachers as useful extensions to the radiological course program. These concepts fit well into competence-oriented curricula.

Hybrid 18F-FDG PET-MRI of the hand in rheumatoid arthritis: initial results

18F-fluorodeoxyglucose PET (18F-FDG PET) is highly sensitive to inflammatory changes within the synovial tissue in rheumatoid arthritis (RA). However, the highest spatial resolution for soft tissue can be achieved with MRI. Here, we report on the first true hybrid PET-MRI examination of the hand in early RA exploiting the advantages of both modalities. PET-MRI was performed with a prototype of an APD-based magneto-insensitive BrainPET detector (Siemens Healthcare, Erlangen, Germany) operated within a standard 3T MR scanner (MAGNETOM Trio, Siemens). PET images were normalized, random, attenuation and scatter-corrected, iteratively reconstructed and calibrated to yield standardized uptake values (SUV) of 18F-FDG uptake. T1-weighted TSE in coronal as well as sagittal orientation prior to and following Gadolinium administration were acquired. Increased 18F-FDG uptake was present in synovitis and tenovaginitis as identified on contrast-enhanced MRI. The tracer distribution was surrounding the metacarpophalangeal joints II and III. Maximum SUV of 3.1 was noted. In RA, true hybrid 18F-FDG PET-MRI of the hand is technically feasible and bears the potential to directly visualize inflammation.

Motion correction improves image quality of dGEMRIC in finger joints

PURPOSE

To assess motion artifacts in dGEMRIC of finger joints and to evaluate the effectiveness of motion correction.

MATERIALS AND METHODS

In 40 subjects (26 patients with finger arthritis and 14 healthy volunteers) dGEMRIC of metacarpophalangeal joint II was performed. Imaging used a dual flip angle approach (TE 3.72 ms, TR 15 ms, flip angles 5° and 26°). Two sets of T1 maps were calculated for dGEMRIC analysis from the imaging data for each subject: one with and one without motion correction. To compare image quality, visual grading analysis and precision of dGEMRIC measurement of both dGEMRIC maps for each case were evaluated.

RESULTS

Motion artifacts were present in 82% (33/40) of uncorrected dGEMRIC maps. Motion artifacts were graded as severe or as rendering evaluation impossible in 43% (17/40) of uncorrected dGEMRIC maps. Motion corrected maps showed significantly less motion artifacts (P<0.001) and were graded as evaluable in 97% (39/40) of cases. Precision was significantly higher in motion corrected images (coefficient of variation (CV=.176±.077), compared to uncorrected images (CV .445±.347) (P<.001). Motion corrected dGERMIC was different in volunteers and patients (P=.044), whereas uncorrected dGEMRIC was not (P=.234).

CONCLUSION

Motion correction improves image quality, dGEMRIC measurement precision and diagnostic performance in dGEMRIC of finger joints.

Utility of synovial biopsy

Synovial biopsies, gained either by blind needle biopsy or minimally invasive arthroscopy, offer additional information in certain clinical situations where routine assessment has not permitted a certain diagnosis. In research settings, synovial histology and modern applications of molecular biology increase our insight into pathogenesis and enable responses to treatment with new therapeutic agents to be assessed directly at the pathophysiological level. This review focuses on the diagnostic usefulness of synovial biopsies in the light of actual developments.