Feasibility of T mapping for the evaluation of hip joint cartilage at 1.5T using a three‐dimensional (3D), gradient‐echo (GRE) sequence: A prospective study

Abstract

This study defines the feasibility of utilizing three-dimensional (3D) gradient-echo (GRE) MRI at 1.5T for T* 2 mapping to assess hip joint cartilage degenerative changes using standard morphological MR grading while comparing it to delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). MRI was obtained from 10 asymptomatic young adult volunteers and 33 patients with symptomatic femoroacetabular impingement (FAI). The protocol included T* 2 mapping without gadolinium-enhancement utilizing a 3D-GRE sequence with six echoes, and after gadolinium injection, routine hip sequences, and a dual-flipangle 3D-GRE sequence for dGEMRIC T 1 mapping. Cartilage was classified as normal, with mild changes, or with severe degenerative changes based on morphological MRI. T 1 and T* 2 findings were subsequently correlated. There were significant differences between volunteers and patients in normally-rated cartilage only for T 1 values. Both T 1 and T* 2 values decreased significantly with the various grades of cartilage damage. There was a statistically significant correlation between standard MRI and T* 2 (T 1 ) (P < 0.05). High intraclass correlation was noted for both T 1 and T* 2 . Correlation factor was 0.860 to 0.954 (T* 2 -T 1 intraobserver) and 0.826 to 0.867 (T* 2 -T 1 interobserver). It is feasible to gather further information about cartilage status within the hip joint using GRE T* 2 mapping at 1.5T. Magn Reson Med 62:896 -901, 2009.

Biochemical MRI Predicts Hip Osteoarthritis in an Experimental Ovine Femoroacetabular Impingement Model

“…We found a normative mean of 25 ms for the T2* relaxation time in sheep. The corresponding reported values in human beings were 23 to 30 ms [13] and 32 ± 4.5 ms [2]. In contrast to the suggested nonlinear T2* response to cartilage degeneration in human beings [3], we found a very linear correlation with a high correlation coefficient.…”

“…Questions/purposes We asked: (1) Does the histological grading of degenerated cartilage correlate with T2 or T2* values in this ovine FAI model? (2) How accurately can zones of degenerated cartilage be predicted with T2 or T2* MRI in this model? Methods A cam-type FAI was induced in eight Swiss alpine sheep by performing a closing wedge intertrochanteric varus osteotomy.…”

Regional Articular Cartilage Abnormalities of the Hip

“…This effect has been used to assess cartilage composition in healthy volunteers and in patients with hip dysplasia, FAI, and hip osteoarthritis [57,59,60]. T2* mapping is a technique similar to T2 mapping, but T2* mapping has shorter scanning times and is more sensitive to susceptibility artifacts [61]. In the hip, Bittersohl et al [34,61] found a significant correlation between T2* relaxation times and dGEMRIC and histologic assessments of the cartilage, respectively.…”

“…T2* mapping is a technique similar to T2 mapping, but T2* mapping has shorter scanning times and is more sensitive to susceptibility artifacts [61]. In the hip, Bittersohl et al [34,61] found a significant correlation between T2* relaxation times and dGEMRIC and histologic assessments of the cartilage, respectively. Other studies have shown that the T2* values of healthy volunteers significantly differed from those of patients with FAI [62,63].…”

Report of Breakout Session: Coxa Profunda/Protrusio Management

“…Several centers have been or still are working on the development of patient-related outcome measures useful for FAI. Advanced imaging techniques such as dGEMRIC and T2 mapping have become available and have been proposed as prognosticators of outcomes of joint-preserving surgery [1]. Well-designed case-control studies using the mentioned tools should identify which treatments allow reduction of symptoms and deceleration of the development of hip OA.…”