Early prediction of response to chemotherapy in metastatic breast cancer using sequential 18F-FDG PET.

UNLABELLED: Chemotherapy is currently the treatment of choice for patients with high-risk metastatic breast cancer. Clinical response is determined after several cycles of chemotherapy by changes in tumor size as assessed by conventional imaging procedures including CT, MRI, plain film radiography, or ultrasound. The aim of this study was to evaluate the use of sequential 18F-FDG PET to predict response after the first and second cycles of standardized chemotherapy for metastatic breast cancer. METHODS: Eleven patients with 26 metastatic lesions underwent 31 (18)F-FDG PET examinations (240-400 MBq of 18F-FDG; 10-min 2-dimensional emission and transmission scans). Clinical response, as assessed by conventional imaging after completion of chemotherapy, served as the reference. 18F-FDG PET images after the first and second cycles of chemotherapy were analyzed semiquantitatively for each metastatic lesion using standardized uptake values (SUVs) normalized to patients' blood glucose levels. In addition, whole-body 18F-FDG PET images were viewed for overall changes in the 18F-FDG uptake pattern of metastatic lesions within individual patients and compared with conventional imaging results after the third and sixth cycles of chemotherapy. RESULTS: After completion of chemotherapy, 17 metastatic lesions responded, as assessed by conventional imaging procedures. In those lesions, SUV decreased to 72% +/- 21% after the first cycle and 54% +/- 16% after the second cycle, when compared with the baseline PET scan. In contrast, 18F-FDG uptake in lesions not responding to chemotherapy (n = 9) declined only to 94% +/- 19% after the first cycle and 79% +/- 9% after the second cycle. The differences between responding and nonresponding lesions were statistically significant after the first (P = 0.02) and second (P = 0.003) cycles. Visual analysis of 18F-FDG PET images correctly predicted the response in all patients as early as after the first cycle of chemotherapy. As assessed by 18F-FDG PET, the overall survival in nonresponders (n = 5) was 8.8 mo, compared with 19.2 mo in responders (n = 6). CONCLUSION: In patients with metastatic breast cancer, sequential 18F-FDG PET allowed prediction of response to treatment after the first cycle of chemotherapy. The use of 18F-FDG PET as a surrogate endpoint for monitoring therapy response offers improved patient care by individualizing treatment and avoiding ineffective chemotherapy.

Lesion of the dorsorostral midbrain sparing the nigrostriatal tract mimics axial rigidity seen in progressive supranuclear palsy.

We report on a patient with a residual dorsorostral midbrain lesion after resection of a pineal gland tumor. In addition to severe vertical gaze palsy, this patient exhibited other neurological features closely resembling progressive supranuclear palsy. Normal dopamine transporter single-photon emission computed tomography imaging excluded significant dopamine deficiency. We suggest that dorsorostral midbrain pathology rather than dopamine deficiency due to degeneration of nigrostriatal dopaminergic neurons or basal ganglia nuclei might be responsible for axial rigidity in extension.

Recurrent Listeria monocytogenes aortic graft infection: confirmation of relapse by molecular subtyping.

Based on molecular typing methods, we identified a rare case of a recurrent L. monocytogenes infection resulting from an infected aortic prosthesis as detected by 18-F-Fluoro-d-deoxyglucose positron emission tomography (FDG PET). Our case highlights the usefulness of molecular typing and nuclear imaging methods for understanding L. monocytogenes pathogenesis and epidemiology.

Long-term effects of "ecstasy" use on serotonin transporters of the brain investigated by PET.

UNLABELLED: Alterations of the serotonergic system due to ecstasy consumption have been extensively documented in recent literature. However, reversibility of these neurotoxic effects still remains unclear. To address this question, PET was performed using the serotonin transporter (SERT) ligand (11)C-(+)-McN5652 in a total of 117 subjects subdivided into 4 groups: actual ecstasy users (n = 30), former ecstasy users (n = 29), drug-naive control subjects (n = 29), and subjects with abuse of psychoactive agents other than ecstasy (n = 29). METHODS: About 500 MBq (11)C-(+)-McN5652 were injected intravenously. Thirty-five scans were acquired according to a dynamic scan protocol of 90 min using a full-ring whole-body PET system. Transaxial slices were reconstructed using an iterative method. Individual brains were transformed to a template defined earlier. Distribution volume ratios (DVRs) were derived by application of a reference tissue approach for reversible binding. Gray matter of the cerebellum served as reference. SERT-rich brain regions--mesencephalon, putamen, caudate, and thalamus--were selected for the evaluation of SERT availability using volumes of interest predefined in the template. RESULTS: Compared with drug-naive control subjects, the DVR in actual ecstasy users was significantly reduced in the mesencephalon (P = 0.004) and the thalamus (P = 0.044). The DVR in former ecstasy users was very close to the DVR in drug-naive control subjects in all brain regions. The DVR in polydrug users was slightly higher than that in the drug-naive control subjects in all SERT-rich regions (not statistically significant). CONCLUSION: Our findings further support the hypothesis of ecstasy-induced protracted alterations of the SERT. In addition, they might indicate reversibility of the availability of SERT as measured by PET. However, this does not imply full reversibility of the neurotoxic effects.