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This prospective study aimed to (1) compare the diagnostic performance of 68Ga-PSMA-11 PET/CT with respect to conventional imaging (computed tomography (CT) and bone scintigraphy (BS)) in the primary staging of high-risk prostate cancer (PCa) patients and (2) validate PSMA-PET/CT accuracy in pelvic nodal staging in comparison with postoperative histopathology and assess PSMA-PET/CT's impact on patient management. Sixty castration-sensitive high-risk (ISUP 4–5 and/or PSA > 20 ng/mL and/or cT3) PCa patients eligible for radical prostatectomy were enrolled (median PSA 10.10 [IQR: 6.22–17.95] ng/mL). PSMA-PET/CT, compared with CT, identified nodal (N) and/or distant metastases (M1) in 56.7% (34/60) vs. 13.3% (8/60) (p < 0.001) of patients: N + 45% vs. 13.3% (p < 0.001), M1a 11.7% vs. 1.7% (p = 0.03), M1b 23.3% vs. 1.7% (p < 0.001). Compared with BS, PSMA-PET/CT localized unknown skeletal metastases in 15% (9/60) of cases, with no false negative findings. Overall, PSMA-PET/CT led to a TNM upstaging in 45.0% (27/60) of cases, with no evidence of downstaging, resulting in a change in management in up to 28.8% (17/59) of patients. Compared with histopathology data (n = 32 patients), the per-patient accuracy of PSMA-PET/TC for detecting pelvic nodal metastases was 90.6%. Overall, the above evidence supports the use of PSMA-PET/CT in the diagnostic workup of high-risk prostate cancer staging. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether the favorable characteristics of novel digital PET/CT (dPET) scanners compared to analog systems (aPET) could translate into an improved disease localization in prostate cancer (PCa) patients with early biochemical recurrence/persistence (BCR/BCP). A retrospective analysis was conducted on 440 consecutive analog (n = 311) or digital (n = 129) 68Ga-PSMA-11 PET/CT scans performed in hormone-sensitive ADT-free PCa patients with early-BCR/BCP (PSA at PET ≤ 2.0 ng/mL), previously treated with radical intent (radical-prostatectomy/radiotherapy). dPET showed a higher positivity rate compared to aPET (48.8% [63/129] vs. 37.3% [116/311], p = 0.03), despite the slightly lower median PSA value of the dPET cohort (0.33 [IQR: 0.26–0.61] vs. 0.55 [IQR: 0.40–0.85] ng/mL, p < 0.01). dPET detection rate was higher in both PSA ranges 0.2–0.5 ng/mL (39.0% [32/82] vs. 25.2% [34/135], p = 0.03) and 0.5–1.0 ng/mL (63.2% [24/38] vs. 40.8% [53/130], p = 0.02), but not for PSA ≥ 1.0 ng/mL. dPET detected a higher per patient median number of pathologic findings (PSMA-RADS ≥ 3) and multi-metastatic cases (>3 lesions) among N1/M1-positive scans (21.7% [10/46] vs. 8.6% [9/105], p = 0.03). Moreover, the proportion of uncertain findings among pathological lesions was significantly lower for dPET than aPET (24.4% [39/160] vs. 38.5% [60/156], p = 0.008). Overall, 68Ga-PSMA-11 dPET showed a better performance compared to aPET, resulting in a higher scan-positivity rate, a higher number of detected pathological lesions, and a lower rate of uncertain findings. [ABSTRACT FROM AUTHOR]

High-resolution intraoperative PET/CT specimen imaging, coupled with prostate-specific membrane antigen (PSMA) molecular targeting, holds great potential for the rapid ex vivo identification of disease localizations in high-risk prostate cancer patients undergoing surgery. However, the accurate analysis of radiotracer uptake would require time-consuming manual volumetric segmentation of 3D images. The aim of this study was to test the feasibility of using machine learning to perform automatic nodal segmentation of intraoperative 68Ga-PSMA-11 PET/CT specimen images. Six (n = 6) lymph-nodal specimens were imaged in the operating room after an e.v. injection of 2.1 MBq/kg of 68Ga-PSMA-11. A machine learning-based approach for automatic lymph-nodal segmentation was developed using only open-source Python libraries (Scikit-learn, SciPy, Scikit-image). The implementation of a k-means clustering algorithm (n = 3 clusters) allowed to identify lymph-nodal structures by leveraging differences in tissue density. Refinement of the segmentation masks was performed using morphological operations and 2D/3D-features filtering. Compared to manual segmentation (ITK-SNAP v4.0.1), the automatic segmentation model showed promising results in terms of weighted average precision (97–99%), recall (68–81%), Dice coefficient (80–88%) and Jaccard index (67–79%). Finally, the ML-based segmentation masks allowed to automatically compute semi-quantitative PET metrics (i.e., SUVmax), thus holding promise for facilitating the semi-quantitative analysis of PET/CT images in the operating room. [ABSTRACT FROM AUTHOR]

Primary umbilical melanoma is rare tumor, representing about 5% of all umbilical malignancies.The lymphatic drainage from the tumor is challenging and can be to inguinal, axillary and retroperitoneal nodes. Dynamic and static lymphoscintigraphy with single-photon emission tomography/computed tomography (SPECT/CT) and sentinel lymph node biopsy (SLNB) is a widely validated technique in patients with clinically localized melanoma to search for and quantify nodal spread of cutaneous melanoma. Moreover, it offers the surgeon the preoperative information about the number and location of the sentinel lymph nodes (SLNs), which makes SLNB easier and quicker. This is the first report of an ulcerated thick melanoma of the umbilicus metastasizing only to an external iliac lymph-node without involvement of superficial inguinal SLNs. The preoperative high-resolution ultrasound (HR-US) examination of the regional lymph node field had been normal. This case-report shows how addition of SPECT/CT to planar imaging in a patient with clinically localized umbilical melanoma can help avoid incomplete SLNB when a deep SLN is not removed. A literature review of umbilical melanoma is also provided. [ABSTRACT FROM AUTHOR]

Objective: To identify the impact of segmentation methods and intensity discretization on radiomic features (RFs) extraction from 68Ga-DOTA-TOC PET images in patients with neuroendocrine tumors. Methods: Forty-nine patients were retrospectively analyzed. Tumor contouring was performed manually by four different operators and with a semi-automatic edge-based segmentation (SAEB) algorithm. Three SUVmax fixed thresholds (20, 30, 40%) were applied. Fifty-one RFs were extracted applying two different intensity rescale factors for gray-level discretization: one absolute (AR60 = SUV from 0 to 60) and one relative (RR = min-max of the VOI SUV). Dice similarity coefficient (DSC) was calculated to quantify segmentation agreement between different segmentation methods. The impact of segmentation and discretization on RFs was assessed by intra-class correlation coefficients (ICC) and the coefficient of variance (COVL). The RFs' correlation with volume and SUVmax was analyzed by calculating Pearson's correlation coefficients. Results: DSC mean value was 0.75 ± 0.11 (0.45–0.92) between SAEB and operators and 0.78 ± 0.09 (0.36–0.97), among the four manual segmentations. The study showed high robustness (ICC > 0.9): (a) in 64.7% of RFs for segmentation methods using AR60, improved by applying SUVmax threshold of 40% (86.5%); (b) in 50.9% of RFs for different SUVmax thresholds using AR60; and (c) in 37% of RFs for discretization settings using different segmentation methods. Several RFs were not correlated with volume and SUVmax. Conclusions: RFs robustness to manual segmentation resulted higher in NET 68Ga-DOTA-TOC images compared to 18F-FDG PET/CT images. Forty percent SUVmax thresholds yield superior RFs stability among operators, however leading to a possible loss of biological information. SAEB segmentation appears to be an optimal alternative to manual segmentation, but further validations are needed. Finally, discretization settings highly impacted on RFs robustness and should always be stated. [ABSTRACT FROM AUTHOR]

Background: The identification of factors responsible for false negative (FN) rate at 18F- Fluorodeoxyglucose (FDG) Positron Emission Tomography /Computed Tomography (PET/CT) in para-aortic (PA) lymph nodes in the presurgical staging of patients with locally advanced cervical cancer (LACC) is challenging. The aim of this study was to evaluate the impact of PET/CT technology.Methods: A total of 240 consecutive patients with LACC (International Federation of Gynecology and Obstetrics, FIGO, stage IB2-IVA) and negative Magnetic Resonance Imaging (MRI) and/or Computed Tomography (CT) and negative 18F-FDG PET/CT in the PA region, undergoing laparoscopic PA lymphadenectomy before chemoradiotherapy were included. The FN rate in patients studied with Time of flight (TOF) PET/CT (TOF PET) or non-Time of flight PET/CT (no-TOF PET) technology was retrospectively compared.Results: Patients presented with FIGO stage IB (n = 78), stage IIA-B (n = 134), stage III (n = 18) and stage IVa (n = 10), squamous cell carcinoma (n = 191) and adenocarcinoma (n = 49). 141/240 patients were evaluated with no-TOF PET/CT and 99/240 with TOF PET/CT. Twenty-two patients (9%) had PA nodal involvement at histological analysis and considered PET/CT FN findings. The FN rate was 8.5% for no-TOF PET and 10% for TOF PET subgroup respectively (p = 0.98). Ninety patients (38%) presented with pelvic node uptakes at PET/CT. The FN rate in the PA region was 18% (16/90) and 4% (6/150) in patients with and without pelvic node involvement at PET/CT respectively (19 vs 3% for no-TOF PET and 17 vs 5% for TOF PET subgroup).Conclusions: In LACC, FN rate in PA lymph nodes detection is a clinical issue even for modern PET/CT, especially in patients with pelvic uptake. Surgical lymphadenectomy should be performed in case of negative PET/CT at PA level in these patients, while it could be discussed in the absence of pelvic uptake. [ABSTRACT FROM AUTHOR]

Background: Elevated postoperative serum calcitonin (Ctn) level indicates persistent/recurrent disease in patients with medullary thyroid carcinoma (MTC). Its location is a challenge. The aim of our study was to compare the disease detection rates of F-18-Dopa (fluoro dihydroxyphenylalanine) positron emission tomography (PET)/computed tomography (CT), whole-body (WB) magnetic resonance imaging (MRI), F-18-FDG (fluorodeoxyglucose) PET/CT, WB CT scanning, neck ultrasonography, and bone scintigraphy in MTC patients with increased Ctn levels and unknown localization of the source. Methods: We compared the independent reading of each imaging procedure with a reference assessment for structural disease defined by pathology or concordance between two imagings or with subsequent follow-up. The detection rate of each imaging modality was determined in per patient, per organ, and per lesion analysis. Results: Thirty-six consecutive patients (21 females, mean age: 57 years, sporadic MTC in 26 cases, median serum Ctn level: 760 pg/mL; range: 21–10,121) were analyzed. The reference assessment localized disease in 24 (64%) patients with 74 lesions detected in the thyroid bed (8), in neck lymph nodes (15), mediastinal lymph nodes (6), lungs (1), liver (2), bones (3), and other site (1). At the patient level, the detection rates were 64% (CI 0.48–0.80) for F-18-Dopa PET/CT with early acquisitions, 40% (CI 0.24–0.56) for F-18-FDG PET/CT, 40% (CI 0.24–0.56) for WB MRI, and 48% (CI 0.31–0.66) for WB CT scan. Conclusions: In MTC patients with increased Ctn and no known distant metastases, F-18-Dopa PET/CT is more sensitive to detect structural disease than any other imaging modality, including WB MRI. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the added value of 18F-Fluorocholine (18F-FCH) PET/CT in presurgical imaging of patients with primary hyperparathyroidism (HPT) and challenging localization of the hyper-functioning parathyroid glands.Methods: We included 27 consecutive patients with primary HPT (19 F; median age: 58 years), with either (i) non-conclusive pre-surgical localization with 99mTc-sestaMIBI scintigraphy and neck ultrasonography (US), (ii) recurrence of previously operated HPT, or (iii) familiar HPT with a suspicion of multiple gland disease. Histological findings and resolution of HPT were considered as the gold standard.Results: 18F-FCH PET/CT was positive in 24/27 patients. Twenty-one patients underwent surgery with 27 resected lesions (14 adenomas, 11 hyperplastic glands, two hyper-functioning histologically normal glands), with resolution of HPT in 19/21 patients (90%). 18F-FCH PET/CT localized 22 lesions in 17/21 patients (per patient: sensitivity 81%, positive predictive value (PPV) 94%; per gland: sensitivity 76%, PPV 85%, specificity 91%, negative predictive value (NPV) 86%). 18F-FCH PET/CT found eight lesions which were undetectable on both 99mTc-sestaMIBI scintigraphy and US. In patients with a familial HPT and/or a multiple gland disease, sensitivity was 100 and 79% on a per-patient and a per-gland analysis respectively, while NPV was 63%. In six patients with a persistence or recurrence of previously treated HPT, 18F-FCH PET/CT localized all lesions, both in sporadic and familiar disease.Conclusions: 18F-FCH PET/CT is a promising modality in challenging pre-surgical localization of hyper-functioning parathyroid glands, such as inconclusive standard imaging, recurrence after surgery, or suspected multiple gland disease. [ABSTRACT FROM AUTHOR]

The author comments on an article about I Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) results in comparison with I Positron Emission Tomography/Computed Tomography (PET/CT) in patients with differentiated thyroid cancer (DTC). The said article appeared in the June 2016 issue of the "European Journal of Nuclear Medicine and Molecular Imaging."

Background/Aim: To evaluate the association between baseline [18F]FDG-PET/CT tumor burden parameters and disease progression rate after first-line target therapy or immunotherapy in advanced melanoma patients. Materials and Methods: Forty four melanoma patients, who underwent [18F]FDG-PET/CT before first-line target therapy (28/44) or immunotherapy (16/44), were retrospectively analyzed. Whole-body and per-district metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated. Therapy response was assessed according to RECIST 1.1 on CT scan at 3 (early) and 12 (late) months. PET parameters were compared using the Mann–Whitney test. Optimal cut-offs for predicting progression were defined using the ROC curve. PFS and OS were studied using Kaplan–Meier analysis. Results: Median (IQR) MTVwb and TLGwb were 13.1 mL and 72.4, respectively. Non-responder patients were 38/44, 26/28 and 12/16 at early evaluation, and 33/44, 21/28 and 12/16 at late evaluation in the whole-cohort, target, and immunotherapy subgroup, respectively. At late evaluation, MTVbone and TLGbone were higher in non-responders compared to responder patients (all p < 0.037) in the whole-cohort and target subgroup and MTVwb and TLGwb (all p < 0.022) in target subgroup. No significant differences were found for the immunotherapy subgroup. No metabolic parameters were able to predict PFS. Controversially, MTVlfn, TLGlfn, MTVsoft + lfn, TLGsoft + lfn, MTVwb and TLGwb were significantly associated (all p < 0.05) with OS in both the whole-cohort and target therapy subgroup. Conclusions: Higher values of whole-body and bone metabolic parameters were correlated with poorer outcome, while higher values of whole-body, lymph node and soft tissue metabolic parameters were correlated with OS. [ABSTRACT FROM AUTHOR]

Objectives: (1.1) to evaluate the association between baseline 18F-FDG PET/CT semi-quantitative parameters of the primary lesion with progression free survival (PFS), overall survival (OS) and response to immunotherapy, in advanced non-small cell lung carcinoma (NSCLC) patients eligible for immunotherapy; (1.2) to evaluate the application of radiomics analysis of the primary lesion to identify features predictive of response to immunotherapy; (1.3) to evaluate if tumor burden assessed by 18F-FDG PET/CT (N and M factors) is associated with PFS and OS. Materials and Methods: we retrospectively analyzed clinical records of advanced NCSLC patients (stage IIIb/c or stage IV) candidate to immunotherapy who performed 18F-FDG PET/CT before treatment to stage the disease. Fifty-seven (57) patients were included in the analysis (F:M 17:40; median age = 69 years old). Notably, 38/57 of patients had adenocarcinoma (AC), 10/57 squamous cell carcinoma (SCC) and 9/57 were not otherwise specified (NOS). Overall, 47.4% patients were stage IVA, 42.1% IVB and 8.8% IIIB. Immunotherapy was performed as front-line therapy in 42/57 patients and as second line therapy after chemotherapy platinum-based in 15/57. The median follow up after starting immunotherapy was 10 months (range: 1.5–68.6). Therapy response was assessed by RECIST 1.1 criteria (CT evaluation every 4 cycles of therapy) in 48/57 patients or when not feasible by clinical and laboratory data (fast disease progression or worsening of patient clinical condition in nine patients). Radiomics analysis was performed by applying regions of interest (ROIs) of the primary tumor delineated manually by two operators and semi-automatically applying a threshold at 40% of SUVmax. Results: (1.1) metabolic tumor volume (MTV) (p = 0.028) and total lesion glycolysis (TLG) (p = 0.035) were significantly associated with progressive vs. non-progressive disease status. Patients with higher values of MTV and TLG had higher probability of disease progression, compared to those patients presenting with lower values. SUVmax did not show correlation with PD status, PFS and OS. MTV (p = 0.027) and TLG (p = 0.022) also resulted in being significantly different among PR, SD and PD groups, while SUVmax was confirmed to not be associated with response to therapy (p = 0.427). (1.2) We observed the association of several radiomics features with PD status. Namely, patients with high tumor volume, TLG and heterogeneity expressed by "skewness" and "kurtosis" had a higher probability of failing immunotherapy. (1.3) M status at 18F-FDG PET/CT was significantly associated with PFS (p = 0.002) and OS (p = 0.049). No significant associations were observed for N status. Conclusions: 18F-FDG PET/CT performed before the start of immunotherapy might be an important prognostic tool able to predict the disease progression and response to immunotherapy in patients with advanced NSCLC, since MTV, TLG and radiomics features (volume and heterogeneity) are associated with disease progression. [ABSTRACT FROM AUTHOR]

The article discusses the case of the 53-year-old man who was diagnosed with parathyroid carcinoma. Mentioned is the use of the fluorocholine positron emission tomography/computed tomography (PET/CT) in treating the disease. The distant metastases of parathyroid carcinoma is explored, along with the differences in tumor differentiation.