Radiographic changes of the proximal third metatarsal bone do not predict presence or severity of proximal suspensory desmopathy in a predominately Quarter Horse population

Abstract

Background: Comparison of radiography to magnetic resonance imaging (MRI) can help objectively assess the value and limitations of radiographs in orthopaedic disease processes. The tarsus and proximal suspensory origin of the metatarsus are commonly imaged regions for lameness. The knowledge gained by comparison between imaging modalities will aid in improving accuracy of radiographic interpretation.Objective: To compare the radiographic and MRI findings of the proximal third metatarsal bone (MTIII) and proximal suspensory ligament using MRI as the gold standard. Study design: Retrospective observational study. Methods: Single hindlimbs of 35 horses with radiographic and high-field (3Tesla (3T)) MRI studies were blindly evaluated by two board-certified veterinary radiologists and a radiology resident. Severity and location of the following parameters were assessed: radiographic MTIII sclerosis and lucent regions, MRI endosteal metatarsal sclerosis and bone marrow lesions, plantar cortical proliferation and resorption, and proximal suspensory desmopathy (PSD).Results: Radiographic osseous changes of MTIII were identified in 54% of limbs, whereas 40% limbs had osseous changes on MRI: 43% of limbs had PSD on MRI. No significant association was found between the presence of radiographic changes in MTIII and PSD on MRI (P = .7). A statistically significant association and positive correlation was found between the severity of radiographic changes and MTIII plantar cortical proliferation and resorption on MRI (P = .01). Main limitations:Retrospective study with no histopathology. Ability to correlate findings with lameness was limited by the lack of standardised time intervals between onset of lameness, diagnostic analgesia and advanced imaging. Conclusion:Radiographic bony changes of proximal MTIII do not reliably predict presence or severity of PSD but are associated with osseous changes at the proximal MTIII. The presence of radiographic changes should warrant additional diagnostics in the region prior to making conclusions about the presence or absence of PSD.

When radiography and ultrasonography are not enough: the use of computed tomography and magnetic resonance imaging for equine lameness cases

“…43 MRI is more sensitive for detection and characterization of lesions of the suspensory ligament, and its bony origin as compared with radiography and ultrasonography. 1,3,44,[103][104][105][106] There is good correlation of suspensory ligament lesion detection with MRI and histopathology. 103 Bone marrow lesions, sclerosis, resorption, and enthesophyte formation within the metacarpal or third metacarpal bone associated with the origin of the ligament can be readily identified in addition to pathology within the ligament itself, including enlargement, irregular margins, and abnormal signal intensity patterns.…”

Findings consistent with equine proximal suspensory desmitis can be reliably detected using computed tomography and differ between affected horses and controls

“…For performing this retrospective, observational, controlled study, CT and radiographic assessment of the PSL (Supporting Information S1). 6,8,11,12 The analysis of bone (B) and soft tissue window (ST) CT image series included the severity (grade 0-3) and localization of PSL findings (2/4/6 cm) with an evaluation of the following categories (Supporting Information S1):…”

“…[1][2][3] The pathology is characterized by a varying combination of osseous changes at the proximoplantar metatarsus III (MTIII), enthesopathy, and desmopathy of the suspensory origin that may cause local nerve compression. [4][5][6] The diagnosis of PSD is generally based on regional analgesia and diagnostic imaging including ultrasonography and radiography. 5,7,8 It has, however, been shown that the majority of ultrasonographic measurements are not very precise and radiographic changes do not reliably predict the presence or severity of PSD.…”

“…5,7,8 It has, however, been shown that the majority of ultrasonographic measurements are not very precise and radiographic changes do not reliably predict the presence or severity of PSD. 6,9 High-field MRI is currently considered the most accurate imaging modality for the evaluation of the proximal suspensory ligament (PSL), but the technique is only available in a small number of referral centers. 11 Low-field MRI shows a detailed morphological correlation with the histological picture of PSD and is diagnostically relevant where other modalities fail to identify the reason for proximal MTIII pain.…”

Highlights of recent clinically relevant papers

“…The aim of this retrospective observational study by Frances Hinkle and co‐workers at Colorado State University , USA , was to compare the radiographic and MRI findings of the proximal third metatarsal bone (MtIII) and proximal suspensory ligament , using MRI as the gold standard .…”