title: Power modulation contrast enhanced ultrasound for postoperative perfusion monitoring following free tissue transfer in head and neck surgery.
abstract: This feasibility study evaluated whether contrast enhanced ultrasound (CEU) was able to assess free flap perfusion following free tissue transfer in the head and neck region. Thirty-six patients underwent standard clinical monitoring (SCM) and CEU postoperatively. The time taken for each technique to detect flap failure was recorded. Qualitative CEU analysis by visual assessment predicted survival in 30/30 (100%) and failure in 5/6 (83%) flaps with sensitivity, specificity, positive (PPV) and negative (NPV) predictive values of 100, 86, 97 and 100%, respectively. Quantitative CEU measurement of blood volume (α) values within healthy perfused flaps was over 60 times higher than in failing flaps (8.25±2.82dB vs. 0.12±0.17dB, respectively, P<0.0001). If a cut-off α value of <1.5dB was used to predict future flap failure, the accuracy of the test was 100% (sensitivity, specificity, PPV, NPV). If a cut-off α value of >1.9dB indicated flap success, the PPV and NPV are 100%. Following surgery, SCM took 76 (±15) h to detect flap failure compared with 18 (±38) h with CEU (P<0.05). CEU is highly accurate in its ability to distinguish between perfused and failing flaps. The technique is quick (<10min) and capable of imaging all flap types.
authors.affiliation: Department of Oral & Maxillofacial Surgery, Poole Hospitals NHS Foundation Trust, Dorset, UK.
authors.forename: S
authors.initials: S
authors.lastname: Sharma
authors.forename: R
authors.initials: R
authors.lastname: Anand
authors.forename: M
authors.initials: M
authors.lastname: Hickman
authors.forename: R
authors.initials: R
authors.lastname: Senior
authors.forename: S
authors.initials: S
authors.lastname: Walji
authors.forename: P L
authors.initials: PL
authors.lastname: Ramchandani
authors.forename: D
authors.initials: D
authors.lastname: Culliford
authors.forename: V
authors.initials: V
authors.lastname: Ilankovan
authors.forename: K
authors.initials: K
authors.lastname: Greaves
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001811:Blood Volume Determination / Q000379:methods*; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D058752:Free Tissue Flaps / Q000098:blood supply*; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007511:Ischemia / Q000000981:diagnostic imaging*; D016015:Logistic Models; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D011183:Postoperative Complications; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019651:Plastic Surgery Procedures; D017211:Treatment Failure; D014463:Ultrasonography / Q000379:methods*; D018608:Ultrasonography, Doppler
chemical_list: D003287:Contrast Media