Histological validation of barium-filled vascular channels detected by high-resolution peripheral quantitative computed tomography in rheumatoid arthritis: an exploratory cadaveric study.

BACKGROUND

High-resolution peripheral quantitative computed tomography (HR-pQCT) enables visualization of erosions and vascular channels (VCs); however, precise characterization of VCs remains challenging. Barium sulfate, an established contrast agent for microvascular imaging, may enhance VC detection on HR-pQCT. However, no study has systematically investigated barium-filled vessels in rheumatoid arthritis (RA) using both histology and HR-pQCT.

METHODS

We examined the 2nd and 3rd metacarpophalangeal joints from a deceased patient with RA, which were perfused with barium sulfate, scanned using first-generation HR-pQCT, and subsequently analyzed histologically.

RESULTS

Histological analysis identified 96 cortical breaks, of which 79 (82%) were confirmed as VCs. HR-pQCT identified 48 VCs in the two fingers. Thirty-three of 51 (65%) histological barium-filled channels were visible on HR-pQCT compared to 15 of 28 (54%) non-barium-filled channels. Barium perfusion was associated with increased VC detectability on HR-pQCT, particularly for larger, collar-shaped cortical breaks. However, smaller or angled VCs were frequently missed due to resolution and preparation constraints, reflecting incomplete vascular perfusion.

CONCLUSION

The findings from this single-specimen exploratory cadaveric study highlight the difficulties of defining VCs on HR-pQCT. Although HR-pQCT provides high spatial resolution, further advancements in imaging techniques are needed to improve the identification of VCs in inflammatory joint diseases. Key Points • HR-pQCT detected only a subset of histologically confirmed vascular channels in rheumatoid arthritis. • A greater proportion of barium-filled vascular channels were visible on HR-pQCT in this specimen with RA. • Despite barium perfusion, small and angled vascular channels were frequently missed by HR-pQCT, and some histologically confirmed VCs did not fulfil the current SPECTRA morphological criteria. • Given that this study is based on a single-specimen, the findings should be considered descriptive and hypothesis-generating rather than confirmatory.