Correlation of FDG-PET hypometabolism and SEEG epileptogenicity mapping in patients with drug-resistant focal epilepsy.

OBJECTIVE: Interictal [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) is used in the presurgical evaluation of patients with drug-resistant focal epilepsy. We aimed at clarifying its relationships with ictal high-frequency oscillations (iHFOs) shown to be a relevant marker of the seizure-onset zone. METHODS: We studied the correlation between FDG-PET and epileptogenicity maps in an unselected series of 37 successive patients having been explored with stereo-electroencephalography (SEEG). RESULTS: At the group level, we found a significant correlation between iHFOs and FDG-PET interictal hypometabolism only in cases of temporal lobe epilepsy. This correlation was found with HFOs, and the same comparison between FDG-PET and ictal SEEG power of lower frequencies during the same epochs did not show the same significance. SIGNIFICANCE: This finding suggests that interictal FDG-PET and ictal HFOs may share common underlying pathophysiologic mechanisms of ictogenesis in temporal lobe epilepsy, and combining both features may help to identify the seizure-onset zone.

Can the sentinel lymph node technique affect decisions to offer internal mammary chain irradiation?

PURPOSE: Identification of the sentinel lymph node (SLN) for small mammary tumours (cT1N0) sometimes leads to detection of internal mammary chain (IMC) drainage. This information is often ignored by physicians. The present study sought to determine the frequency with which an internal mammary SLN was identified by peritumoral injection of radioactive tracer, and then to determine the patients in whom identification of an internal mammary SLN could have an impact on the radiation treatment plan. MATERIALS: Between March 2002 and March 2008, 622 SLN biopsies performed in a cohort of 608 patients were analysed. Technetium-labelled nanocolloids were administered via three peritumoral injections, completed by a deep prepectoral injection, with the entire procedure performed under echographic guidance. RESULTS: The SLN was identified in 607 of the 622 patients, including 174 (28.7%) in the IMC. A total of 161 successful internal mammary biopsies were performed. Of the 622 patients, 18 showed SLN involvement in the IMC. In 7 of these patients, only the internal mammary SLN was affected. Prophylactic irradiation of the IMC was indicated in 376 patients, but only in 18 (4.8%) of these patients was there effectively IMC involvement; internal mammary SLN biopsy failed in 7 patients (1.9%). CONCLUSION: SLN detection by peritumoral injection, combined with the systematic removal of the internal mammary SLN, enabled the involvement of this region to be found in a nonnegligible number of patients. Such information should make it possible to personalize treatment for patients with stage cT1 mammary cancer and thereby avoid needless internal mammary radiation therapy in a large number of patients (93.4% in our study).

Study of inter- and intra-observer reproducibility in the interpretation of [(18)F]choline PET/CT examinations in patients suffering from biochemically recurrent prostate cancer following curative treatment.

BACKGROUND: The aim of this study was to investigate the reproducibility of intra- and inter-observer interpretation of [(18)F]choline positron emission tomography/computed tomography examinations in patients suffering from biochemically recurrent prostate cancer following curative treatment. METHODS: A total of 60 patients with biochemical recurrence after curative treatment were included in this bicentric study. The interpretations were based on a systematic analysis of several anatomic regions and all the four nuclear medicine physicians used identical result consoles. The examinations were interpreted with no knowledge of the patients' clinical context. Two months later, a second interpretation of all these examinations was performed using the same method, in random order. RESULTS: To evaluate local recurrences, when the prostate is in place, the results showed moderate inter- and intra-observer reproducibility: concordance of all 4 physicians has a Fleiss' kappa coefficient of 0.553 with a confidence interval of (0.425 to 0.693). For patients who had had a prostatectomy, there was excellent concordance for the negative examinations. For the lymphatic basin, inter- and intra-observer reproducibility was excellent with a Fleiss' kappa coefficient of 0.892 with a confidence interval of (0.788 to 0.975). The lymphatic sub-group analysis was also good. For the lymphatic groups in the right or left hemi-pelves, all Fleiss' kappa and Cohen's kappa coefficients are varying from 0.760 to 1 with narrow confidence intervals from (0.536 to 0.984) to (1 to 1) in favour of good/excellent inter-observer reproducibility. To evaluate bone metastasis, inter-observer reproducibility was good with a Fleiss' kappa coefficient of 0.703 and a confidence interval of (0.407 to 0.881). CONCLUSION: Our study is at time the only one on the reproducibility of interpretation of [(18)F]choline positron emission tomography/computed tomography examinations, which is a key examination for the treatment of patients suffering biochemical recurrence of prostate cancer. Interpretation of the [(18)F]choline positron emission tomography/computed tomography examination is not so useful at prostate level in patients not previously treated with prostatectomy but has a great interest on patients treated by prostatectomy. It showed good concordance in the interpretation of sub-diaphragmatic lymphatic recurrences as well as in bone metastasis.