The Impact of 68Ga-DOTATATE PET/CT Imaging on Management of Patients with Neuroendocrine Tumors: Experience from a National Referral Center in the United Kingdom.

UNLABELLED: (68)Ga-DOTATATE PET/CT scanning is a widely accepted method for imaging of neuroendocrine tumors. This cross-sectional study was performed to review the first 8 y of patient data from a large (68)Ga-DOTATATE PET/CT database in order to establish the impact of the modality on patient treatment and survival. METHODS: Demographic data, clinical outcome, survival, and change in management after (68)Ga-DOTATATE PET/CT were evaluated. RESULTS: Between May 2005 and August 2013, 1,258 (68)Ga-DOTATATE PET/CT scans were obtained in 728 patients with confirmed or suspected neuroendocrine tumors. In most patients, the primary site was located in the midgut (26.4%). Analysis of NET grading in patients with known histopathologic data revealed that 35.7% had NET grade G1, 12.2% G2, and 8.7% G3. The most common indications for (68)Ga-DOTATATE PET/CT were follow-up (24.4%) and initial tumor staging (23.4%). Of the 1,258 (68)Ga-DOTATATE PET/CT scans completed, 75.7% were positive and 24.3% negative; there were 14 false-positive and 29 false-negative scans. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 97%, 95.1%, 96.6%, 98.5%, and 90.4%, respectively. In 40.9% of patients, the treatment plan was changed after the scans, owing mainly to new, unexpected findings. Statistically significant differences in survival were shown between patients with G1, G2, and G3 grade tumors (P < 0.0001) and also between patients with bone metastasis versus patients with soft-tissue metastasis (P < 0.0001). CONCLUSION: (68)Ga-DOTATATE PET/CT scanning is safe and influences management in a large proportion of patients. Prognosis was dependent on tumor grade, and the presence of bone metastasis was associated with worse overall survival.

Clinical value of supine and upright myocardial perfusion imaging in obese patients using the D-SPECT camera.

PURPOSE: We have assessed whether additional upright imaging increases the confidence of interpretation of stress only supine myocardial perfusion imaging (MPI) in obese patients. METHODS AND RESULTS: Tc-MIBI stress MPI of 101 consecutive patients (M = 49, 62 ± 12 years) with BMI ≥30 scanned on the D-SPECT cardiac camera were assessed. Images were interpreted as diagnostic or equivocal and the need for a rest study was recorded. Stress supine MPI was interpreted first, then gated and finally upright data were added. Defects on supine but not on upright were defined as artefacts and defects seen on both as abnormal. The total perfusion deficit (TPD) was also quantified. There were 27 normal, 22 abnormal, and 52 equivocal supine scans. The median EF was 52%, unaffecting the need for rest imaging. Upright imaging reclassified 32/52 (62%) equivocal studies as normal and 6/52 (11%) as abnormal (P < 0.001). Rest scan was deemed needed in 74/101 patients on supine vs 42/101 on supine/upright (P < 0.001). Supine TPD was normal in 53 and supine/upright TPD was normal in 70 patients (P < 0.001). CONCLUSION: Supine stress MPI is inadequate in obese patients. The addition of upright imaging significantly increases the ability to interpret scans as diagnostic and may reduce considerably the need for rest imaging.

Flare response versus disease progression in patients with non-small cell lung cancer.

We present a case report of a patient with metastatic non-small cell lung cancer (NSCLC) who had a series of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans for assessment of response to treatment. A restaging 18F-FDG PET/CT scan after six cycles showed increased FDG activity in the bone lesions with reduced activity in the lung and liver lesions. The increased bone activity was considered to be due to flare phenomenon rather than metastasis. A short interval follow up scan after 1 month was advised to confirm this interpretation but this repeat scan showed disease relapse. Although the flare phenomenon does exist, caution should be exercised in attributing increased tracer uptake in the lesions in patients with adenocarcinoma of lung and especially those who have received erlotinib during the course of their treatment. Distinguishing the 'flare phenomenon' and 'disease progression' is at times difficult but is important since misdiagnosis may result in an unnecessary delay in patient management.