Background/Purpose: To investigate the ability of whole-body magnetic resonance imaging (WBMRI) to visualize synovitis, bone marrow edema and erosions in patients with rheumatoid arthritis (RA) and to examine the agreement between findings from WBMRI and clinical examination.

Methods:

3 Tesla WBMR images were acquired in a head-to-toe scan using an integrated quadrature body coil and 6 imaging stations in 20 patients with RA (14/6 women/men, aged median 54 [range 21–76] years, disease duration 6 [1–20] years) and at least 1 swollen or tender joint. Imaging time was 1 hour 25 min. STIR and pre- and post contrast T1-weighted images were evaluated for the presence/absence of disease manifestations in 76 joints, 30 entheses and in the spine by one experienced reader (IE). Each location was assessed as not imaged, imaged but not readable or readable. Clinical tender and swollen joint counts of 66 joints were performed. 

Results:

Signs of disease activity were more frequently found by MRI evaluation than by clinical evaluation, table 1.

Table 1. Proportions of joints with signs of synovitis, bone marrow edema, erosions and readable images, and clinical signs of joint involvement.

	Whole-body MRI Evaluation						Clinical Evaluation
	Synovitis		Bone marrow edema		Erosions		Tender joints	Swollen joints
Joints evaluated	% with synovitis*	% Readable	% BME*	% Readable	% with erosions*	% Readable	% (N=18)	% (N=18)
Sternoclavicular	0	60	0	50	0	67.5	11	0
Acromioclavicular	50	85	35	85	0	87.5	ND	ND
Shoulder	61	90	33	90	10	97.5	33	6
Elbow	23	32.5	8	30	0	40	17	8
Wrist	67	82.5	45	82.5	19	80	36	19
1 CMC	92	60	65	50	16	92.5	19	0
1-5 MCP	28 (27–39)	84 (75-90)	12 (7–27)	79.5 (70-85)	3 (0–16)	89.5 (82.5-95)	25 (17–33)	25 (6–33)
1-5 PIP hands	15 (3–25)	77 (63–83)	7 (4–13)	71 (58–78)	3 (3–6)	83 (75-87.5)	31 (19–39)	11 (0–17)
2-5 DIP hands	0	63 (58–70)	0	56 (50–63)	0	72 (70–82.5)	13 (8–17)	0 (0–3)
Hip	25	100	10	100	0	100	17	NA
Knee	32	95	26	95	8	95	52	3
Ankles	50	100	7.5	100	5	100	52	22
TMT	62.5	100	37.5	100	10	100	ND	ND
MTP	35 (31–49)	95 (93–98)	31 (13–47)	92 (90–98)	18 (8–31)	99 (98–100)	36 (22–44)	11 (0–14)
PIP feet	10 (0–15)	79 (65–85)	9 (0–20)	60 (50–75)	0	94 (93–95)	2 (0–6) [0]	0 (0)
DIP feet	0 (0–3)	78 (68–78)	0	48 (48)	0	93 (93–95)	ND	ND
*Numbers given as % of the total number of readable joints, median (range). CMC: carpometacarpal joints; MCP: metacarpophalangeal joints; PIP: proximal interphalangeal joints; DIP: distal interphalangeal joints; TMT: tarsometatarsal joints; NA: not applicable;ND: not done

Synovitis was most frequent in 1^stcarpometacarpal joints (CMC), wrist, the tarsometatarsal (TMT) and shoulder joints (92%, 67%, 63% and 61%, respectively). BME was most frequently present in CMC, wrist, shoulder and  the acromio-clavicular joints (65%, 45%, 33% and 35%, respectively). Erosions were seen primarily in the wrist, MTP, CMC, shoulder and TMT joints (19%, 18%, 16%, 10% and 10%, respectively).

In the spine abnormal findings were less frequent. BME was seen in all cervical disco-vertebral units (DVUs) (7% of evaluated cervical DVUs), and in a few DVUs in the thoracic-lumbar spine (3% of evaluated thoracic- and lumbar DVUs). Fat infiltrations were found in the cervical and lumbar (but not thoracic) spine (3% of evaluated cervical and lumbar DVUs), and erosions were only seen in a single patient in the lumbar spine.

The most frequently involved entheses were those at greater trochanter, calcaneus, greater tuberosity of the humerus, medial condyle of the femur, and upper patella (60%, 26%, 26%, 16% and 13%, respectively, readability 75–100%). The entheses at costo-sternal joints 1 and 7, elbow, lower patella and tubers of the tibia were only readable in 40%, 10%, 25-35%, 5% and 0% of cases, respectively).

MRI findings (synovitis and BME) and clinical findings (tenderness and swelling) were not correlated, neither on the patient level (counts of involved joints) nor consistently on the level of individual joints.

Conclusion: Inflammation (synovitis and BME) in peripheral and axial joints and entheses could be identified by WBMRI, and was more frequent than detected clinically. 3T WB-MRI is a promising tool for evaluation of disease manifestations in RA patients. Optimization of positioning of the feet and hands and acquisition of images is needed.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/whole-body-magnetic-resonance-imaging-of-disease-manifestations-in-axial-and-peripheral-joints-and-entheses-in-rheumatoid-arthritis-patients/