68ga-dotanoc and Intestinal-Neoplasms

The aim of this study was to compare retrospectively 18F-DOPA PET/CT versus 68Ga-DOTANOC PET/CT in a group of patients affected by midgut NET.. Patients with histologically proven grade 1 or grade 2 midgut NET were explored after injection of 150 MBq of 68Ga-DOTANOC and 210 MBq of 18F-DOPA. The PET/CTs were analyzed visually and semiquantitatively at the patient level, regional level (7 defined regions), and lesion level (maximum of 5 lesions/organ). The criterion standard was determined on the basis of histology and imaging follow-up.. Thirty patients (17 males and 13 females; median age, 63.5 years [37-82 years]) were included. Both PET/CTs were negative in 3 patients and positive in 25 patients. PET/CTs were discordant in 2 patients, with 18F-DOPA positive and 68Ga-DOTANOC negative. 18F-DOPA PET/CT detected more involved regions and more metastatic lesions than 68Ga-DOTANOC PET/CT in 6 (20%) and 10 (33.3%) patients, respectively. Of the 81 confirmed affected regions, 77 (95%) were detected by 18F-DOPA PET/CT and 71 (87.7%) by 68Ga-DOTANOC PET/CT (P < 0.0001). 18F-DOPA PET/CT detected significantly more lesions (211/221) than 68Ga-DOTANOC PET/CT (195/221), corresponding to a sensitivity of 95.5% and 88.2%, respectively (P < 0.0001). Tumor-to-background ratios were more favorable in liver for 18F-DOPA than for 68Ga-DOTANOC. Interestingly, a correlation was found between 18F-DOPA SUVmax and tumor burden and especially with the number of regions involved by the disease (P = 0.019).. 18F-DOPA PET/CT is superior to 68Ga-DOTANOC PET/CT for the detection of lesions, and when available, this tracer may be recommended as the first-line examination for an accurate staging of midgut NET.

Topics: Adult; Aged; Aged, 80 and over; Dihydroxyphenylalanine; Female; Humans; Intestinal Neoplasms; Male; Middle Aged; Neuroendocrine Tumors; Organometallic Compounds; Pancreatic Neoplasms; Positron Emission Tomography Computed Tomography; Retrospective Studies; Stomach Neoplasms

Increase in incidence of neuroendocrine tumors (NETs) has been attributed in part to the availability of sensitive diagnostic modalities, such as Ga-DOTA-peptide PET/CT. However, it suffers from problems such as obscurement of tracer-avid lesions by physiological gut activity and collapsed gut lumen. Contrast-enhanced CT and CT enterography (CTE) do not have these drawbacks.. The aim of this study was to compare the diagnostic performances of contrast-enhanced CT + CTE and the Ga-DOTA-peptide PET/noncontrast CT in GEP-NETs.. Fifty-six patients (mean age, 57.8 ± 13.3 years [male:female, 1.95:1]), with histopathologically proven gastroenteropancreatic NETs, who had undergone both Ga-DOTANOC-PET/NCCT (60 minutes, post-IV injection of 111-185 MBq) and contrast-enhanced CT (CECT) + CTE (using 1.5-2 L isotonic mannitol solution and 1-2 mg/kg of IV contrast), were retrospectively selected. Twenty-three patients had been referred for identification of primary lesions and 33 for staging/restaging. The scans were independently evaluated by 2 blinded physicians, who documented the number and site of lesions, with reporting confidence (3 = high confidence, 2 = equivocal confidence, 1 = low confidence). Reference standard was created using clinical, biochemical, and imaging parameters (ie, uptake and contrast enhancement), along with corroboration from previous or follow-up scans. Finally, PET images coregistered to the CECT + CTE were independently evaluated for any additional benefit.. The numbers of primary lesions detected by CECT + CTE and PET/CT were 69 and 57, respectively. Lesion-wise sensitivities for patients with unknown primary in CECT + CTE and PET/CT were 57.7% (95% confidence interval [CI], 39.0%-74.5%) and 71.4% (95% CI, 52.9%-84.7%), respectively. Corresponding numbers in patients who had come for staging/restaging were 73.2% (95% CI, 58.1%-84.3%) and 73.8% (95% CI, 58.9%-84.7%). Lesions missed in CECT + CTE were gastrointestinal (n = 14), lymph nodes (n = 25), mesenteric (n = 1), and pancreatic (n = 7), whereas corresponding numbers for PET/CT were 14, 5, 3, and 2. Contrast-enhanced CT + CTE showed more false-positives (n = 26) than PET/CT (n = 9). Lesions missed by CECT + CTE were smaller than detected lesions (median, 9.7 mm [interquartile range, 7.5-31.1] vs 17.7 mm [interquartile range, 12.2-30.0]; P = 0.062), and lesions missed by PET had significantly lower tumor/background (liver) SUVmax ratio (median, 1.3 [interquartile range, 0.6-3.8] vs 4.7 [interquartile range, 2.7-10.8]). The ratio of true-positives to false-positives dropped markedly, when reporting confidence in CECT + CTE was low (4/15 [for rating 1 or 2] vs 93/11 [rating 3]). Corresponding numbers for PET/CT were (40/7 [for rating 1 or 2] vs 80/2 [rating 3]). Combination of these 2 modalities would have increased the lesion-wise sensitivities in patients with unknown primaries to 89.7% (95% CI, 73.6%-96.4%) and the confidence rating of soft tissue lesions to predominantly high (134 lesions rated 3, and 10 rated 1 or 2).. PET/CT is a sensitive modality for staging and restaging well-differentiated NETs. Use of CECT + CTE as a complementary modality in patients with uncertain uptake or high clinical suspicion of gastroenteropancreatic NETs should be considered, as it improves the lesion detection and reporting confidence.

Topics: Adult; Aged; Female; Humans; Intestinal Neoplasms; Male; Middle Aged; Neuroendocrine Tumors; Organometallic Compounds; Pancreatic Neoplasms; Positron Emission Tomography Computed Tomography; Retrospective Studies; Stomach Neoplasms

A 58-year-old woman with 5-year history of grade 1 progressive metastatic intestinal neuroendocrine tumor with metachronous liver metastases initially treated by surgery and liver embolization underwent Ga-DOTANOC PET/CT before Lu-DOTATATE therapy. Ga-DOTANOC PET/CT revealed increased uptake in several liver metastases and right iliac lymph nodes, consistent with radiopeptide therapy, including a hypodense isthmic thyroid nodule. Fine needle ultrasound-guided biopsy of the thyroid nodule was realized. Immunohistochemistry was positive for CD56, chromogranin, and synaptophysin and negative for calcitonin, confirming neuroendocrine tumor intrathyroid metastasis. Lu-DOTATATE SPECT/CT showed therapeutic uptake on the thyroid metastasis.

Topics: Female; Humans; Intestinal Neoplasms; Middle Aged; Neuroendocrine Tumors; Octreotide; Organometallic Compounds; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals; Thyroid Neoplasms

This study aimed to compare the diagnostic performance of Ga-DOTANOC PET/CT with F-FDG PET/CT in the patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs).. Data of 51 patients with definite histological diagnosis of GEP-NET who underwent both Ga-DOTA-NOC PET-CT and F-FDG PET-CT within a span of 15 days were selected for this retrospective analysis. Sensitivity, specificity, and predictive values were calculated for Ga-DOTA-NOC PET-CT and F-FDG PET-CT, and results were compared both on patientwise and regionwise analysis.. Ga-DOTA-NOC PET-CT is superior to F-FDG PET-CT on patientwise analysis (P < 0.0001). On regionwise analysis, Ga-DOTA-NOC PET-CT is superior to F-FDG PET-CT only for lymph node metastases (P < 0.003). Although Ga-DOTA-NOC PET-CT detected more liver and skeletal lesions compared with F-FDG PET-CT, the difference was not statistically significant. In addition, the results of combined imaging helped in selecting candidates who would undergo the appropriate mode of treatment, whether octreotide therapy or conventional chemotherapy. Ga-DOTA-NOC PET-CT seems to be superior to F-FDG PET-CT for imaging GEP-NETs. However, their role seems to be complementary because combination of Ga-DOTA-NOC PET-CT and F-FDG PET-CT in such patients helps demonstrate the total disease burden and segregate them to proper therapeutic groups.

Topics: Adolescent; Adult; Aged; Female; Fluorodeoxyglucose F18; Humans; Intestinal Neoplasms; Male; Middle Aged; Multimodal Imaging; Neoplasm Metastasis; Neuroendocrine Tumors; Organometallic Compounds; Pancreatic Neoplasms; Positron-Emission Tomography; Radioactive Tracers; Retrospective Studies; Stomach Neoplasms; Tomography, X-Ray Computed