Search

OBJECTIVE: The current standard imaging recommended for primary staging of intermediate- and high-risk prostate cancer (PCa) consists of bone scintigraphy (BS) and computed tomography (CT). Some patients will have equivocal lesions or divergent findings on BS and CT, leading to inconclusive disease staging. Our aim was to investigate the value of 68Ga-PSMA-11 PET/CT in PCa with inconclusive disease stage based on standard imaging.METHODS: We made a single-center study of patients with newly diagnosed PCa who underwent a 68Ga-PSMA-11 PET/CT due to equivocal findings or discrepancies between BS and CT from 1 January 2017 to 31 December 2020. The value of 68Ga-PSMA-11 PET/CT was evaluated for each location of equivocal findings (regional lymphnode, nonregional lymphnodes, bones and other metastases) and on a patient level.RESULTS: Seventy-six patients were included in the study (62 patients with 72 equivocal lesions, 14 with discrepancy between BS and CT). Equivocal lesions were predominately in the bones (61%, 44/72), or in the regional lymph nodes (17%, 12/72). 68Ga-PSMA-11 PET/CT provided a conclusive diagnosis in 90% (65/72) of the equivocal lesions. All patients with discrepancies between BS and CT had definite answers after 68Ga-PSMA-11 PET/CT. 68Ga-PSMA-11 PET/CT also uncovered 32 additional sites of metastasis in 25 patients not visible by standard imaging.CONCLUSION: 68Ga-PSMA-11 PET/CT provides a definite disease stage in more than 90% of newly diagnosed patients with inconclusive standard imaging. Furthermore, it revealed additional sites of metastasis in 25 patients not detected by standard imaging.

Objective: Patients with indeterminate thyroid cytology often have a diagnostic hemithyroidectomy. The role of molecular imaging, particularly fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET), is controversial, and demographic variations in tumor prevalence and histology influence test performance and clinical utility. We retrospectively assessed the prevalence of indeterminate thyroid cytology and the malignancy rate in patients from an iodine deficient area, and evaluated the diagnostic value of preoperative thyroid scintigraphy and 18F-FDG PET/CT among operated patients.Subjects and methods: From 2006-2018, all patients with indeterminate thyroid cytology from the North Denmark region were included in the study (population 600,000).Clinical data, including operation rate, preoperative molecular imaging, and histopathological diagnosis, were retrieved. The results from preoperative thyroid scintigraphy and 18F-FDG PET/CT-scanning were compared to the final histopathological diagnosis.Results: Four hundred and thirty-three patients were found with indeterminate thyroid cytology.The main registered reasons for conducting a fine needle aspiration biopsy (FNAB) were "cold nodule", goiter or a palpable nodule (n=312). In 40 patients (9%), FNAB was registered as conducted due to a PET incidentaloma. Four hundred and two patients (93%) underwent diagnostic lobectomy, and this population formed the study population for the following explorative study: One-hundred and two patients (25%) had a malignant diagnosis. In 226 (56%) and 51 (25%) patients, respectively, preoperative thyroid scintigraphy and 18F-FDG PET/computed tomography (CT) was performed. Among patients with a final malignant disease who had a thyroid scintigraphy (40 patients), a cold nodule was seen in 90% of cases; one (atypical) patient presented a warm nodule. Among patients with a final malignant disease 16 patients (16%) had a 18F-FDG PET (incl. 3 missing PET scans). Among the 51 patients with preoperative 18F-FDG PET/CT, no difference in the PET-derived parameters was found between benign (n=33) and malignant tumors (n=13).Conclusion: The prevalence of malignancy (25%) was comparable with that in other studies. In patients with a preoperative thyroid scintigraphy, 90% of malignant cases had a cold nodule on scintigraphy. In patients with a preoperative PET/CT-scanning presenting focal 18F-FDG-uptake, PET-derived parameters had no diagnostic value. However, the diagnostic value of 18F-FDG-avidity vs. non-avidity needs to be addressed prospectively. Objective: Patients with indeterminate thyroid cytology often have a diagnostic hemithyroidectomy. The role of molecular imaging, particularly fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET), is controversial, and demographic variations in tumor prevalence and histology influence test performance and clinical utility. We retrospectively assessed the prevalence of indeterminate thyroid cytology and the malignancy rate in patients from an iodine deficient area, and evaluated the diagnostic value of preoperative thyroid scintigraphy and 18F-FDG PET/CT among operated patients.Subjects and methods: From 2006-2018, all patients with indeterminate thyroid cytology from the North Denmark region were included in the study (population 600,000).Clinical data, including operation rate, preoperative molecular imaging, and histopathological diagnosis, were retrieved. The results from preoperative thyroid scintigraphy and 18F-FDG PET/CT-scanning were compared to the final histopathological diagnosis.Results: Four hundred and thirty-three patients were found with indeterminate thyroid cytology.The main registered reasons for conducting a fine needle aspiration biopsy (FNAB) were "cold nodule", goiter or a palpable nodule (n=312). In 40 patients (9%), FNAB was registered as conducted due to a PET incidentaloma. Four hundred and two patients (93%) underwent diagnostic lobectomy, and this population formed the study population for the following explorative study: One-hundred and two patients (25%) had a malignant diagnosis. In 226 (56%) and 51 (25%) patients, respectively, preoperative thyroid scintigraphy and 18F-FDG PET/computed tomography (CT) was performed. Among patients with a final malignant disease who had a thyroid scintigraphy (40 patients), a cold nodule was seen in 90% of cases; one (atypical) patient presented a warm nodule. Among patients with a final malignant disease 16 patients (16%) had a 18F-FDG PET (incl. 3 missing PET scans). Among the 51 patients with preoperative 18F-FDG PET/CT, no difference in the PET-derived parameters was found between benign (n=33) and malignant tumors (n=13).Conclusion: The prevalence of malignancy (25%) was comparable with that in other studies. In patients with a preoperative thyroid scintigraphy, 90% of malignant cases had a cold nodule on scintigraphy. In patients with a preoperative PET/CT-scanning presenting focal 18F-FDG-uptake, PET-derived parameters had no diagnostic value. However, the diagnostic value of 18F-FDG-avidity vs. non-avidity needs to be addressed prospectively.

Additional file 1.

OBJECTIVE: To evaluate the diagnostic accuracy of observers with different levels of experience in reading 18F-sodium fluoride (NaF) PET/CT images for the diagnosis of bone metastases in prostate cancer (PCa) patients.METHODS: Nine observers with varying NaF PET/CT experience, ranging from no experience to 2000+ examinations, evaluated 211 NaF PET/CT scans from PCa patients participating in one of four prospective trials. Each observer evaluated each NaF PET/CT on a patient level using a trichotomous scale: M0 (no bone metastases), Me (equivocal for bone metastases) and M1 (bone metastases). Subsequently, a dichotomous evaluation was conducted (M0/M1). The final diagnosis was retrieved from the original study. For each observer, ROC curves and the diagnostic accuracy were calculated based on dichotomous and trichotomous scales; in the latter case, Me was first regarded as M1 and then M0.RESULTS: Across all experience levels, the sensitivity, specificity and accuracy using the dichotomous scale ranged from 0.81 to 0.89, 0.93 to 1.00 and 0.91 to 0.94, respectively. Employing the trichotomous scale, novice and experienced observers chose Me in up to 20 vs. 10% of cases, respectively. Considering Me as M0, the sensitivity, specificity and accuracy ranged from 0.78 to 0.89, 0.95 to 1.00 and 0.91 to 0.95, respectively. Considering Me as M1, the sensitivity, specificity and accuracy ranged from 0.86 to 0.92, 0.71 to 0.96 and 0.77 to 0.94, respectively.CONCLUSION: Novice observers used the equivocal option more frequently than observers with NaF PET/CT experience. However, on the dichotomous scale, all observers exhibited high and satisfactory accuracy for the detection of bone metastases, making NaF PET/CT an effective imaging modality even in unexperienced hands.