Superb microvascular imaging (SMI) detects increased vascularity of the torn anterior cruciate ligament

Abstract

PurposeUltrasound with superb microvascular imaging (SMI) is a novel microvascular imaging technology which may be useful to assess the vascularity of the torn anterior cruciate ligament (ACL) as a potential measure of healing potential following surgery. This study aimed to quantify the vascularity of the torn and intact ACL using ultrasound with SMI. Methods23 patients (mean age ± standard deviation, 27.1 ± 12.8 years), who were diagnosed with an ACL tear with an intact contralateral ACL were enrolled (ACL injury group). Ten healthy volunteers (36.1 ± 4.9 years) who had intact ACLs in both knees were also recruited (ACL healthy controls). The vascularity of the ACL was assessed using SMI within 15 mm from the tibial insertion in both knees. The amount of the vascular signal was assessed using a semi‐quantitative grading scale (vascularity grade: grade 0–3) and a quantified ratio of vascularized area with respect to total area of the region of interest (vascularity ratio). ResultsIn the ACL injury group, a significantly higher vascularity grade and ratio were observed in the torn ACL (vascularity grade 0–3: 1, 8, 7, and 7 patients, respectively; vascularity ratio: 1.3 ± 1.4%) than the contralateral intact ACL (vascularity grade 0–3: 21, 1, 1, and 0 patients, respectively; vascularity ratio: 0.1 ± 0.5%) (P < 0.001), whereas no significant difference was observed between both ACLs in the ACL healthy control group. ConclusionsSMI was useful to assess the increased vascularity in torn ACL, which may reflect the potential for, or state of, ACL maturation following reconstruction or repair. Level of evidenceLevel III.

Preoperative ultrasound predicts the intraoperative diameter of the quadriceps tendon autograft more accurately than preoperative magnetic resonance imaging for anterior cruciate ligament reconstruction

“…Specifically, in situ QT thickness as measured on preoperative US was the most predictive of intraoperative QT graft diameter size. These findings are similar to a previous retrospective study that found moderate to strong correlation between the intraoperative diameter of the QT autograft and the in situ QT thickness and CSA [41]. However, to assess the actual predictive ability of both modalities, a prospective study was needed.…”

“…Preoperative MRI was performed with a standardized protocol for ACL injury using a 1.5 T open‐bore magnet (GE Signa, GE Healthcare, Chicago, Illinois, USA). All assessments using preoperative MRI were performed based on a previously validated protocol [41]. The maximum QT thickness at 15 mm proximal to the superior pole of the patella was assessed on a T2‐weighted sagittal image (MRI thickness at 15 mm) (Fig.…”

“…The maximum QT thickness at 15 mm proximal to the superior pole of the patella was assessed on a T2‐weighted sagittal image (MRI thickness at 15 mm) (Fig. 3) [41]. The QT CSA was assessed at the central 10 mm of the medial–lateral QT width using a T2‐weighted axial image, again, at 15 mm proximal to the superior pole of the patella (MRI CSA at 15 mm) (Fig.…”

“…The QT CSA was assessed at the central 10 mm of the medial–lateral QT width using a T2‐weighted axial image, again, at 15 mm proximal to the superior pole of the patella (MRI CSA at 15 mm) (Fig. 4) [41]. As the axial MRI slices are not exactly perpendicular to the longitudinal axis of the QT (i.e., the measured CSA is likely to overestimate the true CSA), the angle between the plane of the axial cuts and a line perpendicular to the QT axis was measured on the sagittal image.…”

Entrapment of the index finger radial collateral ligament in the metacarpophalangeal joint: A case report

“…SMI may be used to improve the diagnostic accuracy of low-grade digital collateral ligament injuries where there may not be a clear disruption in the ligament substance. Early research on grading of vascularity using SMI in the musculoskeletal system 12,13 has already seen promising results, and with improvements in the technology and conducting similar studies in the hand, it may be possible to stratify and grade injuries to smaller ligaments such as DCL injuries. There are two important limitations to the usage of this technology.…”