Brian P. Jacob, David C. Chen, Bruce Ramshaw, Shirin Towfigh (eds.) - The SAGES Manual of Groin Pain-Springer International Publishing (2016)

19 Radiologic Evaluation for Postoperative Groin Pain
259
Fig. 19.2. Axial MR T1-weighted, T2-weighted, and fat-saturated T2-weighted
images of bilateral flat mesh repairs. Both mesh are intact; however, large superficial
fluid collections are seen bilaterally ( black arrows ). While simple seroma
would appear bright on T2 sequences only, this fluid is also intermediately bright
on T1 sequences, suggesting the presence of significant blood products. Both
groins were percutaneously drained, demonstrating hematoma.
Subacute blood products should appear bright on T1, differentiating
between hematoma and abscess [ 5 ]. If uncertainty still exists, contrast
may be utilized to demonstrate peripheral enhancement in abscess.
Additionally, diffusion- weighted imaging (DWI) may be used to differentiate
the diffusion-restricting abscess (DWI bright, ADC dark) from
organizing hematoma, although early hematoma may restrict as well
(Fig. 19.2 ) [ 6 ].
Mesh Complications
Mesh complications often present with subtle imaging findings, and
may require knowledge of the operative technique utilized to diagnose
definitively. US does not reliably identify the mesh, especially if it is
folded, balled up, or otherwise complicated (Fig. 19.3 ). As such, US is
not recommended as a first-line imaging modality to evaluate the postoperative
groin after mesh implantation when the integrity of the mesh
itself is in question. Due to the combination of low material density and
minimal profile, normal mesh material is often indistinguishable from
surrounding tissue on CT [ 2 ], requiring the radiologist to discern a postoperative
state from the presence and location of the patient’s surgical
scars (Fig. 19.4 ). Even in states of chronic inflammation (e.g., mesh
reaction), it may be impossible to specifically identify pathology on the
basis of CT alone. On MR, flat mesh materials appear as dark linear
bands on T1 sequences, slightly thicker than normal fascial planes, but
may be more difficult to identify among their surrounding tissues on
fluid-sensitive sequences (Fig. 19.5 ).