Figure 3

Beneficial use of retrospective image fusion in a case of recurrent tumour disease. The presented case (no. 27, rpT2 pNx pMx) has suspected recurrent disease after resection of a squamous cell carcinoma of the floor of the mouth and tongue and reconstruction with a microvascular radial forearm flap and adjuvant radiation. A: The tissue by MRI alone was rated as probably malign, attributable to the abnormal contrast enhancement in the right posterior site of the floor of the mouth (red arrow). The region near the midline of the residual tongue (white arrow) was interpreted as an anatomical alteration after surgery and irradiation. B: PET alone showed a moderate increase of tracer up-take near the midline and both PET alone and the side-by-side analysis were rated as "probably benign". C: Retrospective image fusion provided the correct diagnosis of recurrent tumour disease through the correct alignment of morphological and functional imaging data; however, the disease was present not in the dorso-lateral region (histology: scar fibrosis) but near the midline in the residual tongue (histology: SCC recurrent disease).