There has been no established qualitative system of interpretation for therapy response assessment using PET/CT for head and neck cancers. The objective of this study was to validate the Hopkins interpretation system to assess therapy response and survival outcome in head and neck squamous cell cancer patients (HNSCC). Methods The study included 214 biopsy-proven HNSCC patients who underwent a posttherapy PET/CT study, between 5 and 24 wk after completion of treatment. The median follow-up was 27 mo. PET/CT studies were interpreted by 3 nuclear medicine physicians, independently. The studies were scored using a qualitative 5-point scale, for the primary tumor, for the right and left neck, and for overall assessment. Scores 1, 2, and 3 were considered negative for tumors, and scores 4 and 5 were considered positive for tumors. The Cohen κ coefficient (κ) was calculated to measure interreader agreement. Overall survival (OS) and progression-free survival (PFS) were analyzed by Kaplan–Meier plots with a Mantel–Cox log-rank test and Gehan Breslow Wilcoxon test for comparisons. Results Of the 214 patients, 175 were men and 39 were women. There was 85.98%, 95.33%, 93.46%, and 87.38% agreement between the readers for overall, left neck, right neck, and primary tumor site response scores, respectively. The corresponding κ coefficients for interreader agreement between readers were, 0.69–0.79, 0.68–0.83, 0.69–0.87, and 0.79–0.86 for overall, left neck, right neck, and primary tumor site response, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the therapy assessment were 68.1%, 92.2%, 71.1%, 91.1%, and 86.9%, respectively. Cox multivariate regression analysis showed human papillomavirus (HPV) status and PET/CT interpretation were the only factors associated with PFS and OS. Among the HPV-positive patients (n = 123), there was a significant difference in PFS (hazard ratio [HR], 0.14; 95% confidence interval, 0.03–0.57; P = 0.0063) and OS (HR, 0.01; 95% confidence interval, 0.00–0.13; P = 0.0006) between the patients who had a score negative for residual tumor versus positive for residual tumor. A similar significant difference was observed in PFS and OS for all patients. There was also a significant difference in the PFS of patients with PET-avid residual disease in one site versus multiple sites in the neck (HR, 0.23; log-rank P = 0.004). Conclusion The Hopkins 5-point qualitative therapy response interpretation criteria for head and neck PET/CT has substantial interreader agreement and excellent negative predictive value and predicts OS and PFS in patients with HPV-positive HNSCC.

An incremental stroke protocol that includes CT perfusion increases diagnostic performance for stroke diagnosis and inter- and intraobserver agreement.

Conventional imaging modalities (CIMs) have limited sensitivity and specificity for detection of metastatic prostate cancer. We examined the potential of a first-in-class radiofluorinated small-molecule inhibitor of prostate-specific membrane antigen (PSMA), N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-18F-fluorobenzyl-l-cysteine (18F-DCFBC), to detect metastatic hormone-naïve (HNPC) and castration-resistant prostate cancer (CRPC). Methods Seventeen patients were prospectively enrolled (9 HNPC and 8 CRPC); 16 had CIM evidence of new or progressive metastatic prostate cancer and 1 had high clinical suspicion of metastatic disease. 18F-DCFBC PET/CT imaging was obtained with 2 successive PET scans starting at 2 h after injection. Patients were imaged with CIM at approximately the time of PET. A lesion-by-lesion analysis of PET to CIM was performed in the context of either HNPC or CRPC. The patients were followed with available clinical imaging as a reference standard to determine the true nature of identified lesions on PET and CIM. Results On the lesion-by-lesion analysis, 18F-DCFBC PET was able to detect a larger number of lesions (592 positive with 63 equivocal) than CIM (520 positive with 61 equivocal) overall, in both HNPC and CRPC patients. 18F-DCFBC PET detection of lymph nodes, bone lesions, and visceral lesions was superior to CIM. When intrapatient clustering effects were considered, 18F-DCFBC PET was estimated to be positive in a large proportion of lesions that would be negative or equivocal on CIM (0.45). On follow-up, the sensitivity of 18F-DCFBC PET (0.92) was superior to CIM (0.71). 18F-DCFBC tumor uptake was increased at the later PET time point (∼2.5 h after injection), with background uptake showing a decreasing trend on later PET. Conclusion PET imaging with 18F-DCFBC, a small-molecule PSMA-targeted radiotracer, detected more lesions than CIM and promises to diagnose and stage patients with metastatic prostate cancer more accurately than current imaging methods.

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ImportanceAnti-N-methyl-d-aspartate receptor (anti-NMDAR) autoimmune encephalitis is an increasingly recognized cause of limbic encephalitis (LE). Prolonged LE and limbic status epilepticus (LSE) share many features. The ability to distinguish between the two is crucial in directing appropriate therapy because of the potential iatrogenesis associated with immunosuppression and anesthetic-induced coma.ObservationsA 34-year-old woman with recurrent LE developed behavioral changes, global aphasia, and repetitive focal and generalized tonic–clonic seizures. Because asymmetric rhythmic delta patterns recurred on electroencephalography (EEG) despite treatment with nonsedating antiepileptic drugs followed by anesthetic-induced coma, an investigation to distinguish LSE from LE was undertaken. Implanted limbic/temporal lobe depth electrodes revealed no epileptiform activity. Brain single-photon emission computerized tomography (SPECT) showed no hyperperfusion, and brain fluorodeoxyglucose-positron emission tomography (FDG-PET) showed hypermetabolism in the left frontal, temporal, and parietal cortices. Anti-N-methyl-d-aspartate receptor autoimmune encephalitis was diagnosed based detection of anti-NMDAR antibody in the cerebrospinal fluid (CSF). With chronic immunosuppression, the resolution of brain FDG-PET abnormalities paralleled clinical improvement.Conclusions and relevanceThis case of anti-NMDAR autoimmune encephalitis illustrates the challenges of distinguishing prolonged LE from LSE. We discuss the parallels between these two conditions and propose a management paradigm to optimize evaluation and treatment.