Clinical examination or whole-body magnetic resonance imaging: the Holy Grail of spondyloarthritis imaging

Whole-body magnetic resonance imaging allows acquisition of diagnostic images in the shortest scan time, leading to better patient compliance and artifact-free images. Methods of clinical examination of the anterior chest wall joints vary between physician groups and consideration of the rules of rib motion is suggested. The type of joint and its synovial lining may also aid imaging/clinical correlation. This well-written study by experts in the field with a standardized design and methodology allows good scientific analysis and suggests the advantages of whole-body magnetic resonance imaging in anterior chest wall imaging. Selection of clinical examination criteria and specific joints may have had an influence on the study results and the lack of association reported.

Th e Holy Grail of magnetic resonance imaging (MRI) is the acquisition of diagnostic images in the shortest scan time, leading to better patient compliance and thereby to images without artifacts. Th e Holy Grail of a scientifi c study is a standardized design and a methodological approach. Th e recent study by Weber and colleagues is written by experts in the fi eld who have utilized both these unwritten commandments [1]. Th ey have used a standard ized design and methodology in their selection of whole-body MRI. Th is allows a good scientifi c analysis of the clinical parameters and imaging in the assessment of anterior chest wall fi ndings in spondyloarthropathy (SpA).
It is arguable, however, that conventional MRI at higher fi elds, with cardiorespiratory gating, allows a more accurate assessment of joints by providing better spatial resolution than whole-body MRI, and the selection of this modality could have led to the inclusion of false positive lesions. Th e poor specifi city and the costeff ectiveness of whole-body MRI has led to questioning its value as a screening investigation in the past [2], and this study may help rethink that approach [1].
Th e selection of an important yet traditionally ignored joint involved in SpA is also intriguing [3]. Th e morphoanatomy of the costovertebral joint, its involvement in enthesitis and the importance of standardized MRI proto cols have been previously stressed [4]. It is not just the imaging of the anterior chest wall joints that needs standardization, but the methods used to clinically examine these joints by diff erent physician groups. Th e clinical assessment using the Maastricht Ankylosing Spondylitis Enthesitis Score protocol relies on palpation pressure [5]. Th is protocol does not deal with the rules of rib motion. Ribs 1 to 5 exhibit primarily 'pump-handle motion' , whereas ribs 6 to 10 exhibit 'bucket-handle motion' . Ribs 11 and 12, which do not articulate with the thoracic cage, undergo 'caliper motion' . Th e clinical examination of each set of ribs and diff ering motion requires varying assess ment, as is performed by sports physicians [6]. Th ese variations may account for some of the results reported.
Furthermore, the reduction of the Mander Enthesis Index, with the selection of the fi rst and seventh rib joints, in the Maastricht Ankylosing Spondylitis Enthesitis Score may also account for the lack of association found [7]. Th e fi rst rib is a synchondrosis or a synostosis, with no movement at the anterior joint [8]. To capture the relevant joints, along with varying types of motion, selection of the second and seventh anterior joints may have produced better correlation.
Th e type of joint and its synovial lining also infl uences variations in involvement and patterns of infl ammation that are seen on imaging. Th e second costal cartilage and its articulation with the manubrium and the body of the Abstract Whole-body magnetic resonance imaging allows acquisition of diagnostic images in the shortest scan time, leading to better patient compliance and artifact-free images. Methods of clinical examination of the anterior chest wall joints vary between physician groups and consideration of the rules of rib motion is suggested. The type of joint and its synovial lining may also aid imaging/clinical correlation. This well-written study by experts in the fi eld with a standardized design and methodology allows good scientifi c analysis and suggests the advantages of whole-body magnetic resonance imaging in anterior chest wall imaging. Selection of clinical examination criteria and specifi c joints may have had an infl uence on the study results and the lack of association reported.
sternum is unique in that it has an interarticular ligament and two synovial membranes. Th is arrangement is similar to the costovertebral joints that demonstrate a charac teristic pattern of infl ammation on MRI in SpA [9]. Th e infl am matory patterns may therefore diff er, allowing better specifi city in SpA.
Whilst stimulating much thought, this well-written study by experts in the fi eld, with its standardized design and methodology, allows a good scientifi c analysis of fi ndings and suggests the advantages of a relatively new imaging variation. Whole-body MRI with its holistic screen ing approach may yet help redefi ne the SpA disease process. Th e selection of clinical criteria, however, may have had an infl uence on the study results and the lack of association reported.