Assessment of bone microcirculation by contrast-enhanced ultrasound (CEUS) and [18F]-positron emission tomography/computed tomography in free osseous and osseocutaneus flaps for mandibular reconstruction: preliminary results.
OBJECTIVE
Postsurgical evaluation of bone microcirculation in osseous and osseocutaneus free flaps by contrast enhanced ultrasound (CEUS) with time intensity curve (TIC) analysis and [18F]-positron emission tomography/computed tomography (Fluoride-PET/CT).


METHODS
10 patients with osseous or osseocutaneus microvascular flaps were evaluated with CEUS. Ultrasound was carried out by an experienced examiner with a high resolution linear probe (6-9 MHz, LOGIQ E9, GE) 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 the evaluation of [18F]-positron emission tomography/computed tomography and the clinical course for at least 2 month.


RESULTS
9/10 patients showed evidence for soft tissue and osseous microcirculation of the transplants in CEUS correlating with the clinical course. The soft tissue parts of the transplant showed a mean value of 84% (range 51-98%) and the bone parts a mean value of 39% (range 11-75%) for the Area under the curve (AuC) compared with the AuC for the anastomotic vessel region. Mean values for time to peak (TTP) were 27,1 sec (range 8.7-52.0 sec) for the anastomotic vessels, 29.3 sec (range 7.9-62.0 sec) for the soft tissue of and 32.0 sec (range 7.4-69.0 sec) for the transplant bone. In 1/10 patients flap failure occurred, after denudation the bone was left as an avascular transplant. AuC showed a mean value of 0.5 % for the bone region compared with the vessel region. Fluoride-PET/CT assessed bone vitality in 7 patients as "good" in 1 patient as "uncertain" and in 1 patient as "poor". CEUS assessment was corresponding with Fluoride-PET/CT in 4 patients, clinical assessment in 6 patients.


CONCLUSIONS
Fluoride-PET/CT is a valuable tool to make an indirect statement about 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 buried free microvascular bone grafts and the osseous part of osseocutaneous flaps and may be used for a steady monitoring in the first postoperative days.
Department of Cranio-Maxillofacial Surgery, Universitätsklinikum Regensburg, Regensburg, Germany. steffen.mueller@klinik.uni-regensburg.de.
S
S
Müller
M
M
Gosau
D
D
Strobel
S
S
Gehmert
A
A
Moralis
T E
TE
Reichert
L
L
Prantl
E M
EM
Jung
D000368:Aged; D000369:Aged, 80 and over; D016025:Bone Transplantation; D003287:Contrast Media; D005260:Female; D005459:Fluorides; D005462:Fluorine Radioisotopes; D058752:Free Tissue Flaps / Q000098:blood supply*; D006085:Graft Survival; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging; D008297:Male; D008334:Mandible / Q000098:blood supply / Q000601:surgery*; D008339:Mandibular Neoplasms / Q000601:surgery; D045423:Microbubbles; D008833:Microcirculation; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D010019:Osteomyelitis / Q000601:surgery; D010743:Phospholipids; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D019651:Plastic Surgery Procedures / Q000379:methods*; D016038:Skin Transplantation / Q000379:methods; D013459:Sulfur Hexafluoride; D014057:Tomography, X-Ray Computed; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D014656:Vascular Surgical Procedures
D003287:Contrast Media; D005462:Fluorine Radioisotopes; D010743:Phospholipids; C420843:contrast agent BR1; D005459:Fluorides; D013459:Sulfur Hexafluoride