Janine Rennert MD, Presenter: Nothing to Disclose

Lukas Prantl MD, Abstract Co-Author: Nothing to Disclose

Ernst Michael Jung MD, Abstract Co-Author: Nothing to Disclose

Postsurgical evaluation of bone microcirculation in osseous and osteocutaneus free flaps by contrast enhanced ultrasound (CEUS) with time intensity curve (TIC) analysis and [18F]-positron emission tomography / computed tomography (Fluoride-PET/CT).

20 patients with osseous or osteocutaneus microvascular flaps were evaluated using CEUS. Ultrasound was carried out by an experienced examiner with a high resolution linear probe (6-9 MHz) after intravenous bolus injection of 2.4 ml SonoVue® (BRACCO, Germany). Time intensity curves (TIC) in selected regions of interest (ROI) were analyzed and compared with [18F]-positron emission tomography / computed tomography and the clinical course over at least 2 month.

In 18/20 patients soft tissue and osseous microcirculation of the transplants could be visualized in CEUS correlating with the clinical course. The maximum enhancement of the soft tissue transplant compared to the feeding vessels was mean 84% (range 51% - 98%) and the bone tissue mean 39% (range 11% - 75%) for the Area under the curve (AuC). Mean values for time to peak (TTP) were 27.1 s (range 8.7 – 52 s) for the anastomotic vessels, 29.3 s (range 7.9 – 62 s) for the soft tissue of and 32 s (range 7.4 – 69.0 s) for the bone transplant. In 2/20 patients failure of the osseous flap occurred, following denudation of the bone, thus being an avascular transplant. AuC in the osseous flap was less than 5 % compared with the vessel region. Fluoride-PET/CT assessed bone vitality in 14 patients as “good” in 4 patient as “indefinite” and in 2 patient as “poor”. CEUS assessment was corresponding with Fluoride-PET/CT in 8 patients, clinical assessment in 6 patients.

Fluoride-PET/CT is a valuable tool for evaluationg the perfusion of the transplanted bone and was used as control in this study. CEUS is a new and promising method for the evaluation of microcirculation of osseous and osteocutaneous free flaps and may be used for a steady monitoring in the first postoperative days.

Vascular complications of free osseous and osteocutaneus flaps for mandibular reconstruction can lead to potentially life-threatening sequelae including graft loss.

Rennert, J, Prantl, L, Jung, E, Assessment of Bone Microcirculation by Contrast-enhanced Ultrasound (CEUS) and [18F]-Positron Emission Tomography/Computed Tomography in Free Osseous and Osteocutaneus Flaps for Mandibular Reconstruction – Preliminary Results.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043421.html