Demonstration of a geode by magnetic resonance imaging: a new light on the cause of juxta-articular bone cysts in rheumatoid arthritis

Is subchondral bone cyst formation in non-load-bearing region of osteoarthritic knee a vascular problem?

Subchondral bone cyst is common in the progressive knee osteoarthritis yet its underlying mechanism remains unclear. In addition to the existing theories such as synovial fluid influx and mechanical contusion, we identified the potential link between vascular pathology and osteoarthritic bone pathologies including cystic lesion formation, particularly in the non-load-bearing region. This new hypothesis for SBC formation in non-load-bearing region for knee, which cannot be explained by the existing theories, will provide us a new angle to understand the pathomechanism and pathophysiology of subchondral bone disturbance in osteoarthritis in addition to the classical biomechanical overloading theories. It might guide us to develop a novel diagnostic and therapeutic approach to treat progressive osteoarthritis via targeting vascular pathology.

MRI of Large Intraosseous Lesions in Patients with Inflammatory Arthritis

OBJECTIVE

The purpose of our study was to evaluate on MRI the occurrence of large cystlike intraosseous lesions in patients with inflammatory arthritis.

SUBJECTS AND METHODS

We prospectively reviewed contrast-enhanced MR images of 128 hands and wrists in 44 patients with clinical presentation of inflammatory arthritis. Large lesions (> or = 1 cm) found on MR images were further evaluated for the presence of a cortical break and intraarticular extension. These data were correlated with clinical and laboratory findings and the duration of arthritis.

RESULTS

We found 26 patients with rheumatoid arthritis, seven with psoriatic arthritis, two with systemic lupus erythematosus, one with HIV-associated arthritis, one with mixed connective tissue disorder, one with paraneoplastic-associated arthritis, one with inflammatory bowel disease arthritis, and five patients with early unclassified inflammatory arthritis. Twelve patients had 16 large intraosseous lesions, none of which were detected on available radiographs (availability of radiographs for large erosions was 75%). A cortical break with intraarticular extension of the large lesions was seen in 12 cases. Four lesions were not intraarticular.

CONCLUSION

Even large intraosseous lesions may be occult on radiography. MRI is a superior technique for detecting these lesions in the small joints of the hand and wrist in inflammatory arthritis. Although large intraosseous erosions often communicate with joints, we observed four large purely intraosseous enhancing lesions without intraarticular connection. Patients with large erosions have a longer duration of inflammatory arthritis.

MR evaluation of radiation synovectomy of the knee by means of intra-articular injection of holmium-166-chitosan complex in patients with rheumatoid arthritis: results at 4-month follow-up

OBJECTIVE

To determine whether MRI is able to demonstrate the effect of radiation synovectomy after the intra-articular injection of holmium-166-chitosan complex for the treatment of rheumatoid arthritis of the knee.

MATERIALS AND METHODS

Fourteen patients aged 36-59 years were treated with 10-20 mCi of holmium-166-chitosan complex. A criterion for inclusion in this study was the absence of observable improvement after 3- or more months of treatment of the knee with disease-modifying anti-rheumatic drugs. MR images were acquired both prior to and 4-months after treatment. Clinical evaluation included the use of visual analog scales to assess pain, and the circumference of the knee and its range of motion were also determined. MR evaluation included measurement of the volume of synovial enhancement and wall thickness, the amount of joint effusion, and quantifiable scoring of bone erosion, bone edema and lymph nodes.

RESULTS

Visual analog scale readings decreased significantly after radiation synovectomy (p < 0.05). MRI showed that joint effusion decreased significantly (p < 0.05), and that the volume of synovial enhancement tended to decrease, but to an insignificant extent (p = 0.107).

CONCLUSION

The decreased joint effusion noted at 4-month follow-up resulted from radiation synovectomy of the rheumatoid knee by means of intra-articular injection of holmium-166-chitosan complex.

Advanced imaging of early rheumatoid arthritis

Advances in MR imaging of arthritis include contrast-enhanced, dynamic, and quantitative imaging techniques. These advances may result in MR imaging becoming the gold standard in diagnosing early RA. MR imaging is a useful technique in diagnosis, follow-up, and evaluation of remission in rheumatic diseases of the joints. Early diagnosis of RA, in the first 6 months after the onset of symptoms, may lead to earlier control and prevent future erosions and deformities.

Low-field magnetic resonance imaging of early subchondral cyst-like lesions in induced cranial cruciate ligament deficient dogs

Six healthy adult male mongrel dogs underwent cranial cruciate ligament transection in the left stifle. Survey radiography of both stifles and low-field (0.064 T) MRI of the left stifle were performed preoperatively and at 2, 6, and 12 weeks postoperatively. Focal changes in signal intensity were seen with MRI in the subchondral bone of the medial tibial condyle at 2 and 6 weeks postoperatively. At 12 weeks postoperative, a cyst-like lesion was detected using MRI in the subchondral bone of the medial tibial condyle in 4 of 6 dogs and a less defined lesion at this site in the remaining 2 dogs. The cyst-like lesion was spherical in shape and showed typical characteristics of fluid with low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and high signal intensity on inversion recovery images. The lesion was seen in the subchondral bone of the caudal medial and/or middle region of the tibial plateau slightly cranial to the insertion of the caudal cruciate ligament. No subchondral cysts were seen in the tibia on radiographs. Histopathologically, the tibia was characterized by a loose myxomatous phase of early subchondral cyst formation.

Gadolinium-DTPA enhanced magnetic resonance imaging of bone cysts in patients with rheumatoid arthritis

OBJECTIVES

To examine the contents of intraosseous cysts in patients with rheumatoid arthritis (RA) through the signal intensity characteristics on gadolinium-DTPA (Gd-DTPA) enhanced magnetic resonance imaging.

METHODS

The hand or foot joints of nine patients with the cystic form of RA (where the initial radiological abnormality consisted of intraosseous cysts without erosions) were imaged before and after intravenous administration of Gd-DTPA. A 0.6 unit, T1 weighted spin echo and T2* weighted gradient echo were used to obtain images in at least two perpendicular planes.

RESULTS

Most cysts showed a low signal intensity on the non-enhanced T1 weighted (spin echo) images and a high signal intensity on the T2* weighted (gradient echo) images, consistent with a fluid content. No cyst showed an enhancement of signal intensity on the T1 weighted images after intravenous administration of Gd-DTPA, whereas synovium hyperplasia at the site of bony erosions did show an increased signal intensity after Gd-DTPA. Magnetic resonance imaging detected more cysts (as small as 2 mm) than plain films, and the cysts were located truly intraosseously. In six patients no other joint abnormalities were identified by magnetic resonance imaging; the three other patients also showed, after Gd-DTPA administration, an enhanced synovium at the site of bony erosions.

CONCLUSIONS

It is suggested that intraosseous bone cysts in patients with RA do not contain hyperaemic synovial proliferation. The bone cysts in patients with the cystic form of RA may be the only joint abnormality.

Magnetic resonance imaging in rheumatology

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