Diagnostic Performances of PET/CT Using Fibroblast Activation Protein Inhibitors in Patients with Primary and Metastatic Liver Tumors: A Comprehensive Literature Review.

PET/CT using radiolabeled fibroblast activation protein inhibitors (FAPIs) is a promising diagnostic tool in oncology, especially when non-increased and/or physiologically high [18F]FDG uptake (as in liver parenchyma) is observed. We aimed to review the role of PET/CT using radiolabeled FAPIs in primary and/or metastatic liver lesions, and to compare their performances with more "conventional" radiopharmaceuticals. A search algorithm based on the terms "FAPI" AND ("hepatic" OR "liver") was applied, with the last update on 1st January 2024. Out of 177 articles retrieved, 76 studies reporting on the diagnostic application of radiolabeled FAPI PET/CT in at least one patient harboring primary or metastatic liver lesion(s) were fully analyzed. Although there was some heterogeneity in clinical conditions and/or study methodology, PET/CT with radiolabeled FAPIs showed an excellent performance in common primary liver malignancies (hepatocarcinoma, intrahepatic cholangiocarcinoma) and liver metastases (mostly from the gastrointestinal tract and lungs). A higher tumor-to-background ratio for FAPIs than for [18F]FDG was found in primary and metastatic liver lesions, due to lower background activity. Despite limited clinical evidence, radiolabeled FAPIs may be used to assess the suitability and effectiveness of FAPI-derived therapeutic agents such as [177Lu]Lu-FAPI. However, future prospective research on a wider population is needed to confirm the excellent performance.

The impact of the COVID-19 pandemic on oncological disease extent at FDG PET/CT staging: the ONCOVIPET study.

PURPOSE: To investigate whether the COVID-19 pandemic and national lockdown had an impact on the extent of cancer disease at FDG PET/CT staging as surrogate marker. METHODS: Retrospective observational study including cancer patients submitted to FDG PET/CT staging from June 1 to October 31, 2020, and June 1 to October 31, 2019, respectively. Data regarding primary tumour, nodal (N) status and number of involved nodal stations, and presence and number of distant metastases (M) were collected. Each scan was classified in limited vs advanced status. Data were aggregated across the study population and tumour type. Bi-weekly frequencies of the observed events were analysed. RESULTS: Six hundred eleven patients were included (240 in 2019 vs 371 in 2020, respectively). A significant increase of advanced disease patients (rate 1.56, P < 0.001), N + or M + patients (rate 1.84 and 2.09, respectively, P < 0.001), and patients with a greater number of involved N stations or M (rate 2.01 and 2.06, respectively, P < 0.001) were found in 2020 compared with data of 2019. Analysis by tumour type showed a significant increase of advanced disease in lymphoma and lung cancer in 2020 compared with 2019 (P < 0.001). In addition, a significant increase of nodal involvement was found in lung, gastro-intestinal, and breast cancers, as well as in lymphoma patients (P < 0.02). A significant increase of distant metastases was found in lung cancers (P = 0.002). CONCLUSION: Cancer patients with advanced disease at FDG PET/CT staging increased in 2020 compared with 2019, following the national lockdown due to the COVID-19 pandemic, 1.5-fold with a significant increase of patients with N or M involvement. Targeted health interventions are needed to mitigate the effects of the pandemic on patient outcome.

18F-Fluoroethylcholine PET/CT Radiomic Analysis for Newly Diagnosed Prostate Cancer Patients: A Monocentric Study.

AIM: The aim of this study is to assess whether there are some correlations between radiomics and baseline clinical-biological data of prostate cancer (PC) patients using Fluorine-18 Fluoroethylcholine (18F-FECh) PET/CT. METHODS: Digital rectal examination results (DRE), Prostate-Specific Antigen (PSA) serum levels, and bioptical-Gleason Score (GS) were retrospectively collected in newly diagnosed PC patients and considered as outcomes of PC. Thereafter, Volumes of interest (VOI) encompassing the prostate of each patient were drawn to extract conventional and radiomic PET features. Radiomic bivariate models were set up using the most statistically relevant features and then trained/tested with a cross-fold validation test. The best bivariate models were expressed by mean and standard deviation to the normal area under the receiver operating characteristic curves (mAUC, sdAUC). RESULTS: Semiquantitative and radiomic analyses were performed on 67 consecutive patients. tSUVmean and tSkewness were significant DRE predictors at univariate analysis (OR 1.52 [1.01; 2.29], p = 0.047; OR 0.21 [0.07; 0.65], p = 0.007, respectively); moreover, tKurtosis was an independent DRE predictor at multivariate analysis (OR 0.64 [0.42; 0.96], p = 0.03) Among the most relevant bivariate models, szm_2.5D.z.entr + cm.clust.tend was a predictor of PSA levels (mAUC 0.83 ± 0.19); stat.kurt + stat.entropy predicted DRE (mAUC 0.79 ± 0.10); cm.info.corr.1 + szm_2.5D.szhge predicted GS (mAUC 0.78 ± 0.16). CONCLUSIONS: tSUVmean, tSkewness, and tKurtosis were predictors of DRE results only, while none of the PET parameters predicted PSA or GS significantly; 18F-FECh PET/CT radiomic models should be tested in larger cohort studies of newly diagnosed PC patients.

Prognostic significance of normalized FDG-PET parameters in patients with multiple myeloma undergoing induction chemotherapy and autologous hematopoietic stem cell transplantation: a retrospective single-center evaluation.

PURPOSE: The purpose of this study was to determine retrospectively, through a single-center evaluation, whether FDG PET-CT normalized semi-quantitative parameters may predict response to induction chemotherapy (iChT) and hematopoietic stem cell transplantation (HSCT), as well as disease progression and progression-free survival in multiple myeloma (MM) patients, thus becoming a tool of personalized medicine. METHODS: Patients undergoing iChT and HSCT with baseline and post-treatment FDG PET-CTs from January 2008 to July 2015 were included. The following baseline and post-treatment parameters were obtained: SUVmax, SUVmean, SUVpeak, MTVsum, TLGsum, rPET (lesion SUVmax/liver SUVmax) and qPET (lesion SUVpeak/liver SUVmean). Baseline-to-post-treatment changes (Δ) were also calculated. Metabolic and clinical laboratory progression or response at follow-up were noted; time-to-metabolic-progression (TMP) was defined as the interval from post-treatment scan to eventual progression at follow-up FDG PET-CTs. Possible association between each functional parameter and metabolic/clinical-laboratory progression or response was determined. Kaplan-Meier curves allowed to depict the TMP trend according to FDG PET-CT parameters. RESULTS: Twenty-eight patients were included. Significantly higher ΔrPET and ΔqPET values were observed in ten patients with "metabolic response", with respect to 18 patients having "metabolic progression" (median 0.62 [IQR 0.32 - 1.34] vs median 0.00 [IQR -0.25 - 0.49] for ΔrPET; P = 0.045; median 0.51 [IQR 0.32 - 1.13] vs median 0.00 [IQR -0.31 - 0.67] for ΔqPET; P = 0.035). Neither normalized nor non normalized parameters differed significantly between the 20 patients with "clinical-laboratory response" and the eight patients with "clinical-laboratory progression". ΔrPET value lower than 0.38 and ΔqPET value lower than 0.27 predicted a significantly shorter TMP (P = 0.003 and P = 0.005, respectively). CONCLUSIONS: Normalized semi-quantitative parameters are effective in predicting persistent response to treatment and shorter TMP in patients with MM undergoing iChT and HSCT.

Lung uptake of fluorine-18 fluoroethyl-choline PET-CT in patients with prostate cancer.

BACKGROUND: Metastatic spreading to the lungs is a negative prognostic factor in patients with prostate cancer (PC). Aim of our study was to assess the prevalence of lung PC metastases in patients with fluorine-18 fluoroethyl-choline (F-18-FECh) PET-CT positive lung lesions and the role of Gleason Score (GS) and common biochemical markers in predicting metastatic spreading to the lungs. METHODS: We retrospectively evaluated the scans of 1283 patients ongoing (F-18-FECh) PET-CT for PC between May 2010 and July 2014. Patients with lung lesion with F-18-FECh uptake were included. Data concerning GS at diagnosis, "trigger" prostate-specific antigen (PSAtr), PSA doubling time (PSAdt), PSA velocity (PSAvel) and ongoing androgen deprivation therapy were collected. PET-CT findings were confirmed by histology or follow-up (FU) and classified as follows: inflammation, primary lung cancer or metastases from tumor other than PC, and lung metastases from PC. RESULTS: Twenty-two patients with F-18-FECh positive lung lesion and available histology or FU were identified. PSAdt was significantly (P=0.029) shorter in patients with lung metastases from PC (median PSAdt 1.7 months, interquartile range [IQR] 1.5-4.1 months) than in patients without lung PC relapse (median PSAdt 6.7 months, IQR 3.9-7.8); PSAvel was significantly (P=0.019) higher in patients with lung metastases from PC (median PSAvel 3.2 ng/mL/month, IQR 0.65-6.65 ng/mL/month) than in patients without lung PC relapse (median PSAvel 0.3 ng/mL/month, IQR 0.2-0.5 ng/mL/month). Patients with lung metastases from PC had significantly (P=0.006) higher GS at diagnosis (median GS 8) than the other ones (median GS 7). CONCLUSIONS: Our analysis shows that the prevalence of F-18-FECh positive lung metastases in patients with PC, especially with higher GS at diagnosis, is higher in presence of a steady increase in PSA values, confirmed by higher PSAvel and shorter PSAdt.

The role of 18F-FDG-PET and PET/CT in patients with colorectal liver metastases undergoing selective internal radiation therapy with yttrium-90: a first evidence-based review.

PURPOSE: To provide a first evidence-based review of the literature on the role of fluorine-18-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography (FDG-PET and PET/CT) in patients with colorectal liver metastases (CRLM) undergoing selective internal radiation therapy (SIRT) with yttrium-90 ((90)Y) microspheres. METHODS: A comprehensive computer literature search was conducted to find relevant published articles on whole-body FDG-PET or PET/CT in patients with CRLM undergoing SIRT. RESULTS: We identified 19 studies including 833 patients with CRLM undergoing SIRT. The role of FDG-PET or PET/CT was analysed in treatment planning, treatment response evaluation, and as prognostic tool. CONCLUSION: FDG-PET and PET/CT provide additional information in treatment evaluation of CRLM patients treated with SIRT and may have a role in treatment planning and patient selection. FDG-PET/CT is emerging as good prognostic tool in these patients.

Diagnostic performance of positron emission tomography/computed tomography using fluorine-18 fluorodeoxyglucose in detecting locoregional nodal involvement in patients with anal canal cancer: a systematic review and meta-analysis.

PURPOSE: The diagnostic performance of positron emission tomography using (18)F-fluorodeoxyglucose (FDG-PET) in detecting nodal involvement in patients with anal canal cancer (ACC) has been investigated by several studies with conflicting results. The aim of our study is to systematically review and meta-analyze published data about this topic. METHODS: A comprehensive computer literature search of PubMed/MEDLINE, Scopus, and Embase databases was carried out on July 10 to find relevant articles concerning the diagnostic performance of FDG-PET in detecting locoregional nodal involvement in patients with ACC. No language restriction was used. Pooled diagnostic performance on a lesion-based analysis was calculated. RESULTS: Seven retrospective and five prospective studies have been reviewed. Six studies allowed assessing pooled sensitivity; five studies allowed assessing pooled specificity. Sensitivity and specificity values of FDG-PET/CT on a lesion-based analysis ranged from 31 to 100% and from 53 to 98%, with pooled estimates of 56% (95% CI: 45-67%) and 90% (95% CI: 86-93%), respectively. CONCLUSIONS: Our meta-analysis demonstrates that FDG-PET is a specific diagnostic tool in detecting locoregional lymph node involvement in patients with ACC. Low sensitivity is a major concern; however, higher sensitivity could be reached combining FDG-PET with MR scan.

The role of fluorine-18-fluorodeoxyglucose positron emission tomography in evaluating the response to tyrosine-kinase inhibitors in patients with metastatic primary renal cell carcinoma.

BACKGROUND: Positron emission tomography-computed tomography (PET-CT) using fluorodeoxyglucose (FDG) is increasingly used in the evaluation of patients with advanced renal cell carcinoma (RCC), primarily for staging purposes. The aim of this paper is to perform a systematic review about the usefulness of PET-CT using FDG in response assessment after treatment with tyrosine-kinase inhibitors (TKIs) in patients with advanced RCC. MATERIALS AND METHODS: The scientific literature about the role of PET-CT using FDG in the assessment of response to treatment with TKIs in patients affected by advanced RCC was systematically reviewed. RESULTS: Seven studies about the role of PET-CT using FDG in the response assessment after treatment with TKIs (essentially sunitinib and sorafenib) in advanced RCC were retrieved in full-text and analysed, to determine the predictive role of this morpho-functional imaging method on patient outcome. CONCLUSIONS: To date, the role of PET-CT using FDG in evaluating the response to TKIs in metastatic RCC patients is still not well defined, partly due to heterogeneity of available studies; however, PET-CT reveals potential role for the selection of patients undergoing therapy with TKIs. The use of contrast-enhanced PET-CT appears to be promising for a "multi-dimensional" evaluation of treatment response in these patients.

Role of 18F-FDG PET/CT in Head and Neck Squamous Cell Carcinoma: Current Evidence and Innovative Applications.

This article provides an overview of the use of 18F-FDG PET/CT in various clinical scenarios of head-neck squamous cell carcinoma, ranging from initial staging to treatment-response assessment, and post-therapy follow-up, with a focus on the current evidence, debated issues, and innovative applications. Methodological aspects and the most frequent pitfalls in head-neck imaging interpretation are described. In the initial work-up, 18F-FDG PET/CT is recommended in patients with metastatic cervical lymphadenectomy and occult primary tumor; moreover, it is a well-established imaging tool for detecting cervical nodal involvement, distant metastases, and synchronous primary tumors. Various 18F-FDG pre-treatment parameters show prognostic value in terms of disease progression and overall survival. In this scenario, an emerging role is played by radiomics and machine learning. For radiation-treatment planning, 18F-FDG PET/CT provides an accurate delineation of target volumes and treatment adaptation. Due to its high negative predictive value, 18F-FDG PET/CT, performed at least 12 weeks after the completion of chemoradiotherapy, can prevent unnecessary neck dissections. In addition to radiomics and machine learning, emerging applications include PET/MRI, which combines the high soft-tissue contrast of MRI with the metabolic information of PET, and the use of PET radiopharmaceuticals other than 18F-FDG, which can answer specific clinical needs.

Multidisciplinary management of difficult/aggressive growth-hormone pituitary neuro-endocrine tumors.

Growth Hormone-secreting adenomas exhibits variable biological behavior and heterogeneous natural history, ranging from small adenomas and mild disease, to invasive and aggressive neoplasms with more severe clinical picture. Patients not cured or controlled after neurosurgical and first-generation somatostatin receptor ligands (SRL) therapy could require multiple surgical, medical and/or radiation treatments to achieve disease control. To date, no clinical, laboratory, histopathological, or neuroradiological markers are able to define the aggressiveness or predict the disease prognosis in patients with acromegaly. Therefore, the management of these patients requires careful evaluation of laboratory assessments, diagnostic criteria, neuroradiology examinations, and neurosurgical approaches to choose an effective and patient-tailored medical therapy. A multidisciplinary approach is particularly useful in difficult/aggressive acromegaly to schedule multimodal treatment, which includes radiation therapy, chemotherapy with temozolomide and other, recent emerging treatments. Herein, we describe the role of the different members of the multidisciplinary team according to our personal experience; a flow-chart for the therapeutic approach of difficult/aggressive acromegaly patients is proposed.

Myocardial perfusion single-photon emission tomography (SPET) and positron emission tomography-computed tomography (PET-CT) imaging for congenitally corrected transposition of great arteries.

Congenitally corrected transposition of great arteries (ccTGA) consists of both atrioventricular and ventriculo-arterial discordance. In patients with ccTGA, the pulmonary artery arises from the left ventricle, whereas the aorta arises from the right ventricle. The burden of the systemic blood pressure on the right ventricle involves an increased risk of coronary artery disease (CAD) and, as a long-term consequence, myocardial hypertrophy and gradual failure. This report describes the case of an adult patient affected by ccTGA who was referred for an episode of atypical chest pain while at rest. First-line diagnostic examinations were inconclusive. Myocardial perfusion single-photon emission tomography (SPET) was performed to exclude CAD, but the congenital abnormalities of the patient's heart made interpretation of the images particularly difficult. A perfusion positron emission tomography-computed tomography (PET-CT) scan with (13)N-ammonia then was suggested, which unmasked an unexpected artifact. The case report demonstrates that hybrid imaging techniques such as SPET-CT and PET-CT should be used systematically when CAD is suspected for patients with abnormal anatomy of the heart, including ccTGA.

11C-Methionine PET/CT in patients with primary hyperparathyroidism and inconclusive pre-operative imaging work-up: diagnostic accuracy and role of semi-quantitative analysis.

OBJECTIVE: 11C-Methionine PET/CT (C-MET) is a promising method in detecting abnormal parathyroid glands in patients with primary hyperparathyroidism (PHPT). The first aim of the study was to evaluate which is the diagnostic role of C-MET in patients with PHPT and inconclusive pre-operative imaging. Second, we aimed to investigate whether C-MET semi-quantitative parameters may reflect biochemical and histological characteristics of involved glands. METHODS: Patients with PHPT, undergoing C-MET after an inconclusive pre-operative imaging and having a parathyroid surgery, were retrospectively included. C-MET visual and semi-quantitative assessment was performed. Parameters, as SUVmax, SUVpeak, SUVmean, functional lesion volume (FLV) and total lesion activity (TLA), were measured for each detected lesion; SUVmean, FLV and TLA were calculated on 40-90% thresholds of SUVmax to define SUVmean40-90, FLV40-90 and TLA40-90, respectively. Results were correlated with patients' clinical-laboratory (calcium and PTH values) and histological data (size and weight of excised glands). Mann-Whitney test was used and P value < 0.05 was considered significant. RESULTS: Thirty-eight patients (36 female, age: 57.69 ± 15.13 years) were included. Pre-operative median calcium and PTH values were 11.1 mg/dl [interquartile range (IQR) 10.6-11.5] and 154.6 pg/ml (IQR 101.8-227.0), respectively. C-MET showed a parathyroid uptake in 30 out of thirty-eight patients (78.9%). Among 42 nodules excised, C-MET correctly detected the side of the neck (right/left) in 30/42 with sensitivity, specificity and accuracy of 79, 75 and 79%, respectively. C-MET correctly identified the exact position (superior/inferior) in 27/42 with sensitivity, specificity and accuracy of 75, 50 and 71%, respectively. SUVpeak, FLV50-70 and TLA40-70 were significantly (P < 0.05) higher in patients with higher PTH results. The histological size resulted significantly (P < 0.05) higher in abnormal glands with higher SUVmax, SUVpeak, FLV40-80 and TLA40-90, the weight was higher in glands with higher SUVpeak, SUVmean40-50, FLV40-80 and TLA40-90. CONCLUSIONS: C-MET showed a good performance in detecting hyperfunctioning parathyroid glands in PHPT patients with inconclusive pre-operative imaging. Semi-quantitative PET-derived parameters closely correlated with PTH as well as with size and weight of the excised gland, thus reflecting some biochemical and histological characteristics of involved glands.

Bone Marrow Activation After Chemotherapy Presenting as Diffuse Skeletal Uptake on 18F-Fluorocholine PET/CT.

ABSTRACT: Diffuse 18F-FDG skeletal uptake due to chemotherapy-induced bone marrow activation is well documented, whereas it has never been reported with 18F-fluorocholine. We described a patient with pelvic recurrence of prostate cancer at 18F-fluorocholine PET/CT. A second PET/CT after docetaxel showed minimal residual activity in pelvis, but it revealed diffuse, intense 18F-fluorocholine skeletal uptake. Considering biochemical and metabolic response and absence of morphologically suspected bone lesions, skeletal hyperactivity was interpreted as chemotherapy-related bone marrow rebound rather than diffuse metastatic involvement, as confirmed by its resolution after treatment ended. The occurrence of such 18F-fluorocholine pattern should be considered to avoid imaging misinterpretation.

Progression to Symptomatic Multiple Myeloma Predicted by Texture Analysis-Derived Parameters in Patients Without Focal Disease at 18F-FDG PET/CT.

This retrospective study is focused on the possible clinical implications of texture analysis-derived PET parameters in patients with smoldering multiple myeloma. Several texture features are significantly associated with progression to symptomatic multiple myeloma and with a shorter time to progression. The results of this study may lead to early identification of patients who could benefit from specific therapies. BACKGROUND: The aim of the study was to determine whether positron emission tomography parameters derived from texture analysis of axial and peripheral skeleton predict progression to symptomatic multiple myeloma (MM) in patients undergoing 18F-​fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) without evidence of focal sites of 18F-FDG uptake. PATIENTS AND METHODS: Patients with smoldering MM who underwent 18F-FDG PET/CT from May 2014 to June 2018 were retrospectively reviewed. Volumes of interest (VOIs) were placed on T5-T7 and L2-L4, iliac crests, and femoral diaphyses. Dedicated software (LIFEx) allowed us to obtain PET-derived first-, second-, and higher order texture features. Possible associations between PET parameters and progression to symptomatic MM were determined. Kaplan-Meier curves allowed to assess time to progression (TTP) based on the PET parameters. RESULTS: Forty-five patients were included: 26 patients (58%) did not meet the criteria for symptomatic MM, but 19 patients (42%) progressed to symptomatic MM. Several texture features extracted from VOIs placed on iliac crests and femoral diaphyses were significantly associated with progression to symptomatic MM and with a shorter TTP (P < .05); conversely, the above-mentioned parameters extracted from VOIs placed on T5-T7 and L2-L4 did not significantly differ among the patients with regard to their progression to symptomatic MM and length of TTP, except for the gray-level zone length matrix-short-zone low-gray-level emphasis and gray-level zone length matrix-low gray-level zone emphasis. Particularly, second- and higher order texture features showed a significant association with the above-mentioned outcomes. CONCLUSION: Texture features derived from PET may be an expression of subtle disease distribution in the axial and peripheral bone marrow.

18F-Fluciclovine Positron Emission Tomography in Prostate Cancer: A Systematic Review and Diagnostic Meta-Analysis.

BACKGROUND: to explore the diagnostic accuracy of 18F-Fluciclovine positron-emission tomography (PET) in prostate cancer (PCa), considering both primary staging prior to radical therapy, biochemical recurrence, and advanced setting. METHODS: A systematic web search through Embase and Medline was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies performed from 2011 to 2020 were evaluated. The terms used were "PET" or "positron emission tomography" or "positron emission tomography/computed tomography" or "PET/CT" or "positron emission tomography-computed tomography" or "PET-CT" and "Fluciclovine" or "FACBC" and "prostatic neoplasms" or "prostate cancer" or "prostate carcinoma". Only studies reporting about true positive (TP), true negative (TN), false positive (FP) and false negative (FN) findings of 18F-fluciclovine PET were considered eligible. RESULTS: Fifteen out of 283 studies, and 697 patients, were included in the final analysis. The pooled sensitivity for 18F-Fluciclovine PET/CT for diagnosis of primary PCa was 0.83 (95% CI: 0.80-0.86), the specificity of 0.77 (95% CI: 0.74-0.80). The pooled sensitivity for preoperative LN staging was 0.57 (95% CI: 0.39-0.73) and specificity of 0.99 (95% CI: 0.94-1.00). The pooled sensitivity for the overall detection of recurrence in relapsed patients was 0.68 (95% CI: 0.63-0.73), and specificity of 0.68 (95% CI: 0.60-0.75). CONCLUSION: This meta-analysis showed promising results in term of sensitivity and specificity for 18F-Fluciclovine PET/CT to stage the primary lesion and in the assessment of nodal metastases, and for the detection of PCa locations in the recurrent setting. However, the limited number of studies and the broad heterogeneity in the selected cohorts and in different investigation protocols are limitation affecting the strength of these results.

The Prognostic Value of 18F-FDG PET Imaging at Staging in Patients with Malignant Pleural Mesothelioma: A Literature Review.

Malignant pleural mesothelioma (MPM) is an aggressive malignancy, frequently diagnosed at locally-advanced/metastatic stages. Due to a very poor prognosis and limited treatment options, the need to identify new prognostic markers represents a great clinical challenge. The prognostic role of metabolic information derived from Positron Emission Tomography (PET) with 18F-Fluoro-deoxy-glucose (18F-FDG) has been investigated in different MPM settings, however with no definitive consensus. In this comprehensive review, the prognostic value of FDG-PET imaging exclusively performed at staging in MPM patients was evaluated, conducting a literature search on PubMed/MEDLINE from 2010 to 2020. From the 19 selected studies, despite heterogeneity in several aspects, staging FDG-PET imaging emerges as a valuable prognostic biomarker, with higher tumor uptake predictive of worse prognosis, and with volumetric metabolic parameters like Metabolic Tumor Volume, (MTV) and Total Lesion Glycolisis (TLG) performing better than SUVmax. However, PET uptake parameters were not always confirmed as independent prognostic factors, especially in patients previously treated with pleurodesis and with a non-epithelioid histotype. Future prospective studies in larger and clinically homogeneous populations, and using more standardized methods of PET images analysis, are needed to further validate the value of staging FDG-PET in the prognostic MPM stratification, with a potential impact on better patient-tailored treatment planning, in the perspective of personalized medicine.

Muscle Recurrence of a Primarily Nodal Follicular Lymphoma Studied by Contrast-Enhanced 18F-FDG PET/CT.

We report the case of a 52-year-old woman with follicular lymphoma localized in the left inguinal region without any extranodal involvement and achieving a complete response after radiotherapy. After a 3-year disease-free interval, muscular recurrence at the left arm was shown by contrast-enhanced F-FDG PET/CT. Contrast-enhanced F-FDG PET/CT performed after immunochemotherapy documented complete disease remission. Lymphoid tissue is usually not present in the skeletal muscle, making muscular lymphomatous involvement quite unusual; muscular relapse of a primarily nodal lymphoma is even rarer.

Incidental Finding of an Ovarian Carcinoid on 11C-Methionine PET/CT.

A 68-year-old woman with a history of multiple myeloma on regular hematological follow-up and with no previous relevant gynecological diseases was found to have an incidental focal uptake by the right ovary at C-methionine PET/CT (C-MET). Transvaginal ultrasound was then performed showing a 2-cm solid right ovarian mass with irregular borders and moderate vascularization at color Doppler examination. Therefore, the patient underwent bilateral salpingectomy, and the final histological results revealed a rare presentation of mature teratoma with insular carcinoid tumor arising from the right ovary.

A Case of Primary Localized Small Bowel Amyloidosis Studied by 18F-Choline and Contrast-Enhanced 18F-FDG PET/CT.

Amyloidosis is a rare hereditary or acquired protein deposition disorder with different etiologies, characterized by pathological protein deposition essentially in nearly any organs or tissues. There are 2 major forms: primary and secondary amyloidosis. Moreover, it is possible to have systemic or localized disease. The localized form of amyloidosis affecting the small intestine is rare, and it is characterized by the formation of precursor proteins at the site of the lesion. We report a case of localized small bowel amyloidosis studied by F-choline and F-FDG-iodinated PET/CT performed for staging an aggressive prostatic cancer.