The dignosis of colorectal cancer by FDG-PET and PET-3DCT angiography

In this chapter, we give an outline about usefulness and limitation for evaluating colorectal cancer by FDG-PET, according to the fields such as detection of primary lesion, lymph node metastasis and recurrence. For the evaluation of primary lesion of colorectal cancer, colonoscopy is enough though evaluation of lymphnode metastasis is not enough by using conventional imaging modalities. We intend to clarify the efficacy of preoperative staging by FDG-PET. Sixty-eight patients who had colorectal cancer histologically proven by biopsy under the colonoscopy were enrolled in this study. Lymphnodes of 68 cases except for paraintestinal area were involved by cancer in 8 patients (12.3%) . The sensitivity, specificity of PET-CT were 60.4%,100%, respectively. For the diagnosis of recurrence, PET can detect lesions with good contrast resolution compared with CT or MRI. 3D imaging reconstructed by fused contrast enhanced CT and FDG-PET are applied for navigation image which have a feature to detect hypermetabolic tumor and vascular structure simultaneously. This kind of image is useful for preoperative mapping by clarifying corelationship between tumor and vessels.