Radiation Changes Do Not Interfere With Postchemoradiation Restaging of Patients With Rectal Cancer by FDG PET/CT Before Curative Surgical Therapy

Value of diffusion-weighted imaging in the detection of viable tumour after neoadjuvant chemoradiation therapy in patients with locally advanced rectal cancer: comparison withT2weighted and PET/CT imaging

“…Although standardised histological examination procedures were used and detailed pathology reports were provided by an experienced pathologist, exact matching between the MR images and histopathological findings for the viable tumour may have been suboptimal. Second, the percentage of complete histopathological responders in our study was 12%, a rate similar to that found by others [20,23,24,[42][43][44]. The small number of cases with pathological CR might, however, have led to overestimation of diagnostic accuracy.…”

“…Many investigators have reported a substantial decrease in standardised uptake value (SUV) post-CRT in responders compared with nonresponders [19][20][21][22]. However, only a few studies have compared the abilities of MRI and PET/CT to enable prediction of responses to neoadjuvant CRT [23,24].…”

Restaging: Should We PERCIST Without Pattern Recognition?

“…Nevertheless, early detection of recurrence is important, because repeated RFA can be performed and is best performed on small recurrences. The question raised by the current study is whether 18 F-FDG PET could identify residual disease more robustly than CT.…”

“…Nevertheless, because PET enables quantification of 18 F-FDG uptake, correlating with the rate of glycolysis, there is a temptation to use this capability for image interpretation (e.g., using semiquantitative measures such as the standardized uptake value [SUV]). The value of pattern recognition has, at times, been forgotten, as evidenced by the adoption of an arbitrary cutoff SUV of 2.5 for characterization of pulmonary nodules (3).…”

“…Symmetric uptake in hilar nodes is a well-known pattern for differentiating inflammatory from malignant lymphadenopathy (6). The typical distribution of brown fat (7,8), the pattern of intense 18 F-FDG uptake in the bowel of patients treated with metformin (9), or elastofibroma dorsi (10) are surprisingly easy to recognize. Indeed, once you appreciate such a pattern, you wonder how you missed it despite seeing it many times before.…”