Assessment of the incorporation of revascularized fibula grafts used for mandibular reconstruction with F-18-PET.
OBJECTIVE
Determination of the range of regional blood flow and fluoride influx during normal incorporation of revascularized fibula grafts used for mandibular reconstruction. Evaluation, if healing complications are preceded by typical deviations of these parameters from the normal range. Assessment of the potential influence of using "scaled population-derived" instead of "individually measured" input functions in quantitative analysis.


METHODS
Dynamic F-18-PET images and arterialized venous blood samples were obtained in 11 patients early and late after surgery. Based on kinetic modeling regional blood flow (K1) and fluoride influx (Kmlf) were determined.


RESULTS
In uncomplicated cases, early postoperative graft K1--but not Kmlf--exceeded that of vertebrae as reference region. Kmlf values obtained in graft necrosis (n = 2) were below the ranges of values observed in uncomplicated healing (0.0113-0.0745 ml/min/ml) as well as that of the reference region (0.0154-0.0748). Kmlf values in mobile non-union were in the lower range--and those in rigid non-union in the upper range of values obtained in stable union (0.0211-0.0694). If scaled population-derived instead of measured input functions were used for quantification, mean deviations of 23 +/- 17% in K1 and 12 +/- 16% in Kmlf were observed.


CONCLUSIONS
Normal healing of predominantly cortical bone transplants is characterized by relatively low osteoblastic activity together with increased perfusion. It may be anticipated that transplant necrosis can be identified by showing markedly reduced F- influx. In case that measured input functions are not available, quantification with scaled population-derived input functions is appropriate if expected differences in quantitative parameters exceed 70%.
Berding
G
G
Department of Nuclear Medicine, University Medical School, Hannover, Germany. berding.georg@mh-hannover.de
Schliephake
H
H
van den Hoff
J
J
Knapp
W H
WH
D000328:Adult; D005260:Female; D005360:Fibula / Q000601:surgery*; D005462:Fluorine Radioisotopes; D006801:Humans; D008297:Male; D008334:Mandible / Q000098:blood supply / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D009336:Necrosis; D018919:Neovascularization, Physiologic; D019651:Plastic Surgery Procedures; D012039:Regional Blood Flow; D012189:Retrospective Studies; D014055:Tomography, Emission-Computed; D014182:Transplantation, Autologous; D016896:Treatment Outcome
D005462:Fluorine Radioisotopes