Evaluation of the degenerative pattern of PCL in osteoarthritis patients using UTE-T2 mapping

Abstract

Background: The posterior cruciate ligament (PCL) is one of the essential stabilizers of the knee joint and it was demonstrated that its degenerative change related to the knee osteoarthritis (OA). We aimed to evaluate signal of the PCL in OA patients in comparison with healthy young and elderly volunteers using the ultra-short echo timeenhanced (UTE)-T2∗ mapping, and to validate these findings with histology.

Methods: Thirty asymptomatic volunteers, 13 young people (younger group) and 17 elderly people (elder group), and 27 patients who had undergone total knee arthroplasty (OA group) were enrolled in this study. UTE-T2∗ maps of PCL were obtained from all participants. The PCL was divided into proximal, middle, and distal parts and the UTET2∗ values obtained from each part were compared among the groups. In OA group, the sacrificed PCLs were evaluated histologically in each part corresponding to the part of UTE-T2∗ maps and compared.

Results: The UTE-T2∗ values in OA group were significantly higher than those in other groups except in distal part. In elder group, the UTE-T2∗ values were significantly higher than those in younger group only in the proximal part. Moreover, in OA group, the UTE-T2∗ values in proximal and middle parts were significantly higher than those in distal part. There was a moderate correlation between the UTE-T2∗ values and histological scores.

Conclusions: The specific signal intensity pattern of the PCL in patients with OA was demonstrated using UTE-T2∗ mapping, and these findings were related to histological degenerated status of the PCL.

Keywords: Magnetic resonance image (MRI); Osteoarthritis (OA); Posterior cruciate ligament (PCL); Ultra-short echo time-enhanced (UTE).

Fig. 1

(A) Manually demarcated ROIs dividing the whole length of the PCL into three parts: proximal; middle; and distal part. (B) Image of UTE-T2∗ color mapping. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

(A, B) Whole length of PCL ( × 40) was divided into three parts (Left to right indicate proximal to distal); (C) proximal, (D) middle, and (E) distal ( × 100).

Fig. 3

Color overlaid UTE T2∗ maps of PCL from (A) younger, (B) elder, and (C) OA group. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 4

Relationship between the UTE T2∗ values and the histological scores.

Fig. 5

Representative case of the histological findings. (A) Severe inflammatory changes, cystic changes, and collapse of collagen fiber orientation were observed. The actual UTE T2∗ value was16.7 and the histological score of 10.5. (B) Collagen fiber orientation was normal with minimal inflammatory changes. The actual UTE T2∗ value of 10.7 and the histological score of 6.