Comparison of cone-beam and fan-beam computed tomography and low-field magnetic resonance imaging for detection of proximal phalanx dorsoproximal osteochondral defects.
Authors: Lin Szu-Ting, Bolas Nicholas M, Sargan David R, Restif Olivier, Peter Vanessa G, Pokora Rachel, Patrick Hayley, Foote Alastair K, Murray Rachel C
Journal: Equine veterinary journal
Summary
# Editorial Summary: Imaging Osteochondral Defects of the Proximal Phalanx Dorsoproximal osteochondral defects are a recognised problem in equine forelimbs, yet diagnostic imaging guidance has been sparse; researchers compared cone-beam CT (CBCT), fan-beam CT (FBCT), and low-field MRI against macroscopic pathology findings in 35 cadaver limbs containing 56 defects across 70 potential lesion sites. Fan-beam CT proved most sensitive at detecting defects (86%), though specificity was moderate at 64%, whilst CBCT and MRI demonstrated lower sensitivities (64% and 52% respectively) but superior specificity (71% for both). All three modalities showed improved detection as defect size increased, and defect dimensions correlated most strongly with CBCT measurements (r = 0.76), though FBCT and MRI showed moderate correlation; importantly, all imaging underestimated lesion size compared to macroscopy, likely because imaging captured bone changes whilst macroscopy included cartilage involvement. Clinically, FBCT offers the best diagnostic yield for detecting osteochondral defects, CBCT provides the most reliable size assessment for surgical planning, and MRI's capacity to reveal fluid signal and bone oedema around defects may help identify active or progressive pathology—making the imaging choice dependent on your specific clinical question and available resources.
Read the full abstract on PubMed
Practical Takeaways
- •Fan-beam CT is the most sensitive imaging modality for detecting osteochondral defects of the proximal phalanx; consider this when diagnostic imaging is critical, though access may be limited.
- •Cone-beam CT provides the most accurate measurement of defect size and may be preferred when available for surgical planning or prognostic assessment.
- •Low-field MRI is less sensitive for detecting these lesions but provides useful complementary information about active pathology (fluid and bone marrow changes); consider combining modalities when diagnosis is unclear.
Key Findings
- •Fan-beam CT demonstrated the highest sensitivity (86%) and specificity (64%) for detecting proximal phalanx osteochondral defects compared to cone-beam CT (64% sensitivity, 71% specificity) and low-field MRI (52% sensitivity, 71% specificity).
- •Cone-beam CT measurements of defect size showed the strongest correlation with macroscopic examination (r = 0.76, p < 0.001), whereas fan-beam CT and MRI showed moderate correlation (r = 0.65, p < 0.001).
- •Sensitivity of all imaging modalities increased with defect size, and MRI provided additional information on fluid signal and subchondral hyperintensity potentially indicating active pathology.
- •All imaging modalities significantly underestimated defect dimensions compared to macroscopic examination (p < 0.001), likely because macroscopy included articular cartilage pathology not fully captured on imaging.