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Metabolic and receptor imaging in patients with neuroendocrine tumors: Comparison of fludeoxyglucose-positron emission tomography and computed tomography with indium in 111 pentetreotide

OBJECTIVE To determine whether positron emission tomography/computed tomography (PET/CT) and indium In 111 pentetreotide, individually or collectively, predict the outcome of patients with neuroendocrine tumors (NETs). METHODS Between July 31, 2002, and May 4, 2007, 29 patients with previously diagnosed NETs underwent both PET/CT and indium In 111 pentetreotide imaging at our institution. The images were evaluated for the presence of abnormalities. Clinical outcomes were classified as survival without major morbidities, survival with severe complications of disease, or death. Time to outcome was measured in months from the imaging date to outcome. Kaplan-Meier survival curves were calculated in which patient outcome was compared with results on PET/CT and indium In 111 pentetreotide imaging. RESULTS Of the 29 patients, 9 had abnormalities on both PET/CT and indium In 111 pentetreotide imaging. Two patients had abnormal findings on PET/CT but normal findings on pentetreotide imaging. In 5 patients, findings were normal on PET/CT but abnormal on pentetreotide imaging. In 13 patients, normal findings were noted on both PET/CT and pentetreotide imaging. Kaplan-Meier analysis demonstrated a significant survival advantage for patients who had normal findings on PET/CT in comparison with abnormal PET/CT findings (P = .01). Patients with normal findings on indium In 111 pentetreotide imaging had a higher but insignificant survival advantage over those with abnormal results on pentetreotide imaging (P = .08). CONCLUSION For evaluation of NETs, PET/CT and indium In 111 pentetreotide are complementary. Increased metabolic activity in tumor cells is reflected by abnormalities on PET/CT. Patients who had abnormal PET/CT findings had a generally poorer prognosis and a more rapid clinical deterioration than those with normal PET/CT findings.

Clinical utility of FDG-PET for diagnosis of adrenal mass: a large single-center experience.

OBJECTIVETo examine the clinical utility of 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) for diagnosing whether an adrenal mass is malignant, in contemporary clinical practice.DESIGNRetrospective medical record review of patients from 2 databases at a large hospital. The first database consisted of patients who underwent FDG-PET between the years 2009 to 2011 while the second database included patients who had histological diagnosis of adrenal mass between the years 1997 to 2011.RESULTS3.4% of 2921 patients had adrenal FDG uptake. Approximately 43% of them did not exhibit corresponding adrenal mass. FDG-PET performance parameters were better if a cutoff of SUV (standardized uptake value) ≥3 was used to define positivity. The imaging characteristics of malignant adrenal masses and pheochromocytoma were similar but differed remarkably compared to those of benign tumors. Serial imaging revealed that the malignant adrenal masses consistently exhibited high CT attenuation, while more than half of them initially exhibited SUV<3 and in some cases FDG uptake indistinguishable from the background. The FDG-PET results were confirmatory in 87% of patients, contributory in 11%, but definitely misleading in 2%.CONCLUSIONSFDG-PET is not required for adrenal mass diagnosis in most patients in contemporary practice but may help clinical decision making in specific situations.

Portable Ventilation/Perfusion Scanning is Useful for Evaluating Clinically Significant Pulmonary Embolism in the ICU Despite Abnormal Chest Radiography

Objective: Computed tomography angiography is limited in the intensive care unit (ICU) due to renal insufficiency, hemodynamic instability, and difficulty transporting unstable patients. A portable ventilation/perfusion (V/Q) scan can be used. However, it is commonly believed that an abnormal chest radiograph can result in a nondiagnostic scan. In this retrospective study, we demonstrate that portable V/Q scans can be helpful in ruling in or out clinically significant pulmonary embolism (PE) despite an abnormal chest x-ray in the ICU. Design: Two physicians conducted chart reviews and original V/Q reports. A staff radiologist, with 40 years of experience, rated chest x-ray abnormalities using predetermined criteria. Setting: The study was conducted in the ICU. Patients: The first 100 consecutive patients with suspected PE who underwent a portable V/Q scan. Interventions: Those with a portable V/Q scan. Results: A normal baseline chest radiograph was found in only 6% of patients. Fifty-three percent had moderate, 24% had severe, and 10% had very-severe radiographic abnormalities. Despite the abnormal x-rays, 88% of the V/Q scans were low probability for a PE despite an average abnormal radiograph rating of moderate. A high-probability V/Q for PE was diagnosed in 3% of the population despite chest x-ray ratings of moderate to severe. Six patients had their empiric anticoagulation discontinued after obtaining the results of the V/Q scan, and no anticoagulation was started for PE after a low-probability V/Q scan. Conclusion: Despite the large percentage of moderate-to-severe x-ray abnormalities, PE can still be diagnosed (high-probability scan) in the ICU with a portable V/Q scan. Although low-probability scans do not rule out acute PE, it appeared less likely that any patient with a low-probability V/Q scan had severe hypoxemia or hemodynamic instability due to a significant PE, which was useful to clinicians and allowed them to either stop or not start anticoagulation.