Type:
Educational Exhibit
Keywords:
Diagnostic procedure, MR, Musculoskeletal joint, Musculoskeletal bone, Education and training
Authors:
G. Freire1, M. H. Valentim2, L. Gargaté1, P. D. Afonso3; 1Loures/PT, 2Lisboa/PT, 3Lisbon/PT
DOI:
10.1594/ecr2018/C-1721
Findings and procedure details
Normal meniscal sutures appear with maintained morphology and high / intermediate signal intensity in T1- and PD-weighted images (WI) but not in T2-WI (that is,
is not “fluid-like”) at the site of repair.
Scar tissue at the repair site frequently leads to linear signal abnormalities on PD-WI,
despite absence of re-tear1.
These findings persist in 50% of the patients,
with a mean follow-up of 12.9 years2.
Different sutures will have distinct imaging features.
Inside-out sutures originate pronounced signal variation and are magnetically susceptible,
producing more MRI artifacts.
(figure 1) All-inside sutures are reabsorbable and produce tenuous signal change on MRI.
Pre-operative MRI and surgical reports for comparison are essential to diagnose new tears,
as most MRI findings of a retear might be specific,
but not sensitive3,4.
Important findings of retorn meniscus are irregular meniscus contour,
high signal intensity extending into the articular surface in T2-WI and a displaced meniscus fragment (meniscal flap - figure 2)5.
The most useful MRI finding for a torn post-operative meniscus is a change in signal pattern compared with baseline MRI5.
The presence of a high signal intensity that contacts the articular surface in T1 and DP and importantly,
on T2-WI (that is,
“fluid-like”) is a specific finding for a retorn meniscus.
The absence of a high signal intensity line through the meniscus on PD- and T2-WI is a sensitive finding for untorn meniscus5.
However,
clinical correlation is always needed.