Incorporation versus infection of retroperitoneal aortic grafts: MR imaging features.

Abstract

The magnetic resonance (MR) imaging characteristics of normal aortic graft healing were compared with those of perigraft infection in 57 patients after aortic graft implantation. Thirty-three patients without postoperative complications underwent MR imaging in a 0.35-T unit 1 week after graft implantation, and 13 of those patients were reexamined 2-3 months after graft implantation. Twenty-four patients with clinically suspected perigraft infection underwent MR imaging 6 weeks to 18 years after graft implantation. Early normal postoperative changes were characterized by a perigraft collar of low to medium signal intensity on T1-weighted images and of high intensity on T2-weighted images in all 33 cases, consistent with perigraft fluid collection. In 10 of 13 patients reexamined 2-3 months postoperatively, the MR images demonstrated a collar of tissue consistent with perigraft fibrosis. In cases of clinical suspicion of retroperitoneal graft infection, MR imaging showed eccentric fluid collections of low to medium signal intensity on T1-weighted images and high intensity on T2-weighted images at more than 3 months after surgery. The MR findings were diagnostic of retroperitoneal perigraft infection in 17 of 20 patients shown to be infected at surgery. Retroperitoneal infection was correctly excluded on the basis of MR findings in four patients. Thus, MR imaging is an accurate imaging method for the diagnosis of aortic graft infection. In the early postoperative phase, resolving perigraft fluid cannot be differentiated from perigraft infection.

Frequency, risk factors, and management of perigraft seroma after open abdominal aortic aneurysm repair

“…The 3-month period was chosen as the upper limit of time for perioperative fluid collections around the graft to resolve based on reports in radiology literature 13 suggesting that with uncomplicated healing, by this time, the aneurysm sac has usually shrunken down completely around the graft. A perigraft collection 3.0-cm or greater in diameter is obviously deviant from a well-healed, incorporated graft.…”

Imaging Modalities for the Diagnosis of Vascular Graft Infections: A Consensus Paper amongst Different Specialists

“…MRI, with its high contrast resolution, can easily demonstrate small perigraft fluid collections but, like CT, it is not able to distinguish the para-physiological perigraft fluid in the early postoperative period from an infected perigraft fluid collection. MRI imaging does not allow for the differentiation of the signal void produced by calcifications of the aortic wall from that of air bubbles in the perigraft infection [23]. In the case of graft infection, MRI can show eccentric fluid collection with low to medium signal intensity on T1-weighted images and high signal intensity on T2-weighted ones.…”

Aortic Prosthetic Graft Infections: Radiologic Manifestations and Implications for Management

“…With MR imaging, it is similarly difficult to distinguish "normal" perigraft fluid in the early postoperative period from an infected perigraft fluid collection (24). With MR imaging, it is similarly difficult to distinguish "normal" perigraft fluid in the early postoperative period from an infected perigraft fluid collection (24).…”