Characterization of Atypical Pheochromocytomas with Correlative MRI and Planar/Hybrid Radionuclide Imaging: A Preliminary Study

Pheochromocytomas may show atypical imaging findings leading to diagnostic pitfalls. We correlated the results of magnetic resonance imaging (MRI) with those of radionuclide studies in patients with pheochromocytomas. T2-weighted (-w), T1-w chemical-shift and T1-w dynamic contrast enhanced (DCE) MRI sequences were evaluated to assess tumor structure. 131Iodine metaiodobenzylguanidine (MIBG) scintigraphy, 18fluoro (F) deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) or FDG PET/MRI were evaluated for direct comparison. Of a total of 80 adrenal lesions in 73 patients, 20 in 18 patients were pheochromocytomas. More than half (55%) of the pheochromocytomas (n = 11) had the typical increased signal intensity on T2-w and T1-w DCE, while the remaining (n = 9) lesions showed atypical findings; of these nine latter atypical lesions, seven (35%) were cystic (two totally, three predominantly and two partially) and two (10%) were hemorrhagic on MRI. In these atypical lesions, MIBG scintigraphy (n = 5), FDG PET/CT (n = 6) or FDG PET/MRI (n = 2) showed inhomogeneous tracer uptake in the residual viable tissue providing tumor characterization; however, one predominantly cystic pheochromocytoma showed false negative MIBG scan. Our preliminary results show that cystic degeneration may be frequent in pheochromocytoma being so marked that only a thin rim of viable cells may residue to disclose the true nature of the tumor. MRI findings together with those of correlative planar/hybrid radionuclide images are helpful to characterize these atypical pheochromocytomas. In particular, tumor accumulation of MIBG and/or FDG is able to classify these lesions as not simple cysts; in detail, the presence of partial MIBG uptake allows the diagnosis of pheochromocytomas, while the presence of partial FDG uptake generically reflects the presence of viable solid tissue of such cystic tumors.

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Head-to-head intra-individual comparison of biodistribution and tumor uptake of 68Ga-FAPI and 18F-FDG PET/CT in cancer patients

European Journal of Nuclear Medicine and Molecular Imaging ◽

10.1007/s00259-021-05307-1 ◽

2021 ◽

Author(s):

Frederik L. Giesel ◽

Clemens Kratochwil ◽

Joel Schlittenhardt ◽

Katharina Dendl ◽

Matthias Eiber ◽

...

Keyword(s):

Fdg Pet ◽

Standard Of Care ◽

Blood Pool ◽

Tracer Uptake ◽

Time Interval ◽

Tumor Uptake ◽

Primary Tumors ◽

Individual Comparison ◽

Pet Ct ◽

Fdg Pet Ct

Abstract Purpose FAPI ligands (fibroblast activation protein inhibitor), a novel class of radiotracers for PET/CT imaging, demonstrated in previous studies rapid and high tumor uptake. The purpose of this study is the head-to-head intra-individual comparison of 68Ga-FAPI versus standard-of-care 18F-FDG in PET/CT in organ biodistribution and tumor uptake in patients with various cancers. Material and Methods This international retrospective multicenter analysis included PET/CT data from 71 patients from 6 centers who underwent both 68Ga-FAPI and 18F-FDG PET/CT within a median time interval of 10 days (range 1–89 days). Volumes of interest (VOIs) were manually drawn in normal organs and tumor lesions to quantify tracer uptake by SUVmax and SUVmean. Furthermore, tumor-to-background ratios (TBR) were generated (SUVmax tumor/ SUVmax organ). Results A total of 71 patients were studied of, which 28 were female and 43 male (median age 60). In 41 of 71 patients, the primary tumor was present. Forty-three of 71 patients exhibited 162 metastatic lesions. 68Ga-FAPI uptake in primary tumors and metastases was comparable to 18F-FDG in most cases. The SUVmax was significantly lower for 68Ga-FAPI than 18F-FDG in background tissues such as the brain, oral mucosa, myocardium, blood pool, liver, pancreas, and colon. Thus, 68Ga-FAPI TBRs were significantly higher than 18F-FDG TBRs in some sites, including liver and bone metastases. Conclusion Quantitative tumor uptake is comparable between 68Ga-FAPI and 18F-FDG, but lower background uptake in most normal organs results in equal or higher TBRs for 68Ga-FAPI. Thus, 68Ga-FAPI PET/CT may yield improved diagnostic information in various cancers and especially in tumor locations with high physiological 18F-FDG uptake.

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The role of 18F-FDG PET/CT in the management of large-vessel vasculitis: applications and limitations in clinical practice

Italian Journal of Medicine ◽

10.4081/itjm.2011.249 ◽

2012 ◽

pp. 249-254

Author(s):

Maria V. Mattoli ◽

Giorgio Treglia ◽

Lucia Leccisotti ◽

Alessandro Giordano

Keyword(s):

Clinical Practice ◽

Fdg Pet ◽

False Negative ◽

Large Vessel Vasculitis ◽

Large Vessel ◽

Metabolic Imaging ◽

Small Vessel Vasculitis ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

Introduction: 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) plays a key role in oncology, and it is now being used increasingly to diagnose, characterize, and monitor disease activity in inflammatory disorders, including vasculitis. Unfortunately, its role in the management of vasculitis is still not well-defined, and clinicians are often unsure how this metabolic imaging technique should be used in these diseases, although its usefulness in diagnosing large-vessel vasculitis has been clearly demonstrated. Materials and methods: We reviewed the literature about the use of PET/CT in the management of vasculitis in an attempt to identify the applications and the limitations of this technique in clinical practice. Results and discussion: Our literature review revealed that 18F-FDG PET/CT is a useful tool for diagnosing vasculitis (especially when the symptoms of the disease are non-specific); guiding biopsy procedures (areas with high glucose consumption); evaluating disease extension; and monitoring treatment responses. The main limitations of this method are the relatively low spatial resolution of the tomograph, which can lead to false-negative results in the presence of small-vessel vasculitis, and risk of false positive results, especially those related to the presence of atherosclerosis and to post-treatment vascular remodeling.

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EVALUATING THE ROLE OF FDG PET-CT SCAN AS A SOLE IMAGING MODALITY IN THE MANAGEMENT OF MUO NECK

10.36106/ijsr/3930114 ◽

2020 ◽

pp. 39-41

Author(s):

Krishnappa Krishnappa ◽

Krishna Prasad ◽

Shruti Satish ◽

Murali R Nadig

Keyword(s):

Ct Scan ◽

Predictive Value ◽

Fdg Pet ◽

Imaging Modality ◽

False Negative ◽

Unknown Primary ◽

Pet Ct ◽

Fdg Pet Ct ◽

Pet Ct Scan

Aim:to study the role of PET- CT SCAN as a single imaging modality in the diagnosis of MUO neck. methodology: retrospective study analysis of 51 cases of clinical unknown primary with cervical metastasis . RESULTS: FDG PET CT tracer uptake was detected in 24/51. true positive in 18 cases out of 24,false positive in 6 cases, false negative in 2 cases with sensitivity of 90%, specificity of 82%,positive predictive value of 75%,negative predictive value of 93% and accuracy of 84.91%. conclusion: FDG PET CT can be used as a sole imaging modality in the diagnosis of MUO neck.it is complimentary to endoscopy.

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Diagnosis of infective endocarditis by 18F-FDG-PET/CT, presentation of a false negative result

Medicina Clínica (English Edition) ◽

10.1016/j.medcle.2018.01.005 ◽

2018 ◽

Vol 150 (6) ◽

pp. 247-248

Author(s):

Beatriz Colina Andrés ◽

Maite Arbulu Tapia ◽

Miguel Ángel Goenaga Sánchez

Keyword(s):

Infective Endocarditis ◽

Fdg Pet ◽

False Negative ◽

False Negative Result ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

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False-Negative and False-Positive Results in FDG-PET and PET/CT in Breast Cancer

PET Clinics ◽

10.1016/j.cpet.2009.09.002 ◽

2009 ◽

Vol 4 (3) ◽

pp. 289-298 ◽

Cited By ~ 10

Author(s):

Rakesh Kumar ◽

Neerja Rani ◽

Chetan Patel ◽

Sandip Basu ◽

Abass Alavi

Keyword(s):

Breast Cancer ◽

False Positive ◽

Fdg Pet ◽

False Negative ◽

Pet Ct ◽

Positive Results

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18F-FDG-PET/CT Imaging in Advanced Glottic Cancer: A Tool for Clinical Decision in Comparison with Conventional Imaging

Contrast Media & Molecular Imaging ◽

10.1155/2019/4051206 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12

Author(s):

G. Paone ◽

F. Martucci ◽

V. Espeli ◽

L. Ceriani ◽

G. Treglia ◽

...

Keyword(s):

Fdg Pet ◽

False Negative ◽

Ct Imaging ◽

Radiotherapy Planning ◽

Glottic Cancer ◽

Conventional Imaging ◽

Prognostic Information ◽

Quantitative Pet ◽

Pet Ct ◽

Fdg Pet Ct

This study assessed the role of 18F-FDG PET-CT (PET/CT) to detect the cartilage and paraglottic infiltration in advanced glottic cancer comparing the results with those of conventional imaging (CI) (contrast-enhanced computed tomography and/or magnetic resonance). In addition, we assessed the prognostic value of quantitative parameters, measured on baseline PET/CT, in terms of event-free survival (EFS) and overall survival (OS). We retrospectively analyzed 27 patients with glottic squamous cell carcinoma stage III and IVA, treated in our institute between 2010 and 2016, comparing PET/CT, performed for staging and radiotherapy planning, and CI findings. Cohen’s K was used to compare concordance between PET/CT and CI. Imaging findings were correlated with endoscopic evaluation and histological reports (gold standard (GS)). All lesions shown by CI were also detected by PET/CT imaging, and in 5 cases, a better definition of local infiltration was achieved with PET/CT than CI (5 CT). Sensitivity, specificity, and accuracy of PET/CT and CT were 95%, 86%, and 93% and 70%, 86%, and 74% for, respectively. MRI showed sensitivity and specificity of 100%. One false-negative (FN) cases and 1 false-positive (FP) case were observed with PET/CT with no difference compared to MRI (10 cases). Six FN cases and 1 FP case were observed with CT. Cohen’s K was 0.60 (PET vs. CI) and 0.80 (PET vs. GS). Patients were followed-up for at least 24 months to calculate EFS and OS. 13 local recurrence and 7 deaths were recorded. Among quantitative PET parameters, baseline MTV was the most powerful predictor of outcome. Our data suggest a reliable sensitivity and accuracy of PET/CT in the evaluation of local extension, proving a useful method for initial local staging in addition to the well-established role in lymph-node and distant sites assessment. Furthermore, pretreatment MTV provides better prognostic information than other PET/CT parameters.

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PS02.064: ACCURACY OF F-18-FDG-PET/CT IN MONITORING TUMOUR RESPONSE AFTER NEOADJUVANT CHEMORADIOTHERAPY IN PATIENTS WITH OESOPHAGEAL CANCER

Diseases of the Esophagus ◽

10.1093/dote/doy089.ps02.064 ◽

2018 ◽

Vol 31 (Supplement_1) ◽

pp. 138-139

Author(s):

Maria Valkema ◽

B Noordman ◽

Bas P L Wijnhoven ◽

M C W Spaander ◽

Sjoerd M Lagarde ◽

...

Keyword(s):

Oesophageal Cancer ◽

Fdg Pet ◽

Conflicts Of Interest ◽

False Negative ◽

Neoadjuvant Chemoradiotherapy ◽

Tumour Response ◽

Distant Metastases ◽

Residual Tumour ◽

Pet Ct ◽

Fdg Pet Ct

Abstract Background Neoadjuvant chemoradiotherapy (nCRT) induces a pathologically complete response in approximately 30% of patients with oesophageal cancer. To explore the possibility of safe postponement of surgery, accurate clinical response evaluations are needed to exclude residual disease. The present study aims to assess the value of F-18-FDG-PET/CT for the detection of residual tumour (> 10% tumour cells = TRG3–4 vs. no vital cells = TRG1) or metastases after nCRT. Methods FDG-PET/CT at baseline and 12 weeks after nCRT was performed according to the European Association of Nuclear Medicine guidelines 1.0 (2.3MBq/kg F-18-FDG; scanning 60 ± 5min.) and the protocol of the preSANO study. Qualitative analysis included sensitive reading of presence of residual tumour and/or metastases. A lesion was considered FDG-positive, when any uptake in the lesion itself was above the adjacent oesophageal background uptake. Quantitatively, SUV/lean body mass (SUL) measurements at tumour, lymph nodes, oesophagus, liver and bloodpool were recorded and compared with pathology (resection specimen: gold standard). Results Some 129 of 207 patients with FDG-avid tumours at baseline proceeded to FDG-PET/CT at around 12 weeks after nCRT just before surgery. Forty-one of 129 patients had TRG3–4, of whom 6 were missed on FDG-PET/CT (15% false negative) with SULmax 2.07 ± 0.25, SUL-ratio tumour/oesophagus (SULR) 1.35 ± 0.14. Sensitivity for TRG2–3-4 vs. TRG1 was 57/71 (80%). SULmax and SULR of FDG-positives were 3.76 ± 1.33 and 1.82 ± 0.69 respectively, compared to SULmax 2.21 ± 0.42 and SULR 1.31 ± 0.22 in FDG-negatives. Distant metastases were detected in 18 of 190 (10%) patients. Of all patients with postponed surgery, 12 had ≥ 1 additional FDG-PET/CT during follow-up (25–49.7 weeks after nCRT). Eventually, 4 patients underwent surgery. Three of 4 had increased FDG-signal and TRG3–4; 1 patient had decreased FDG-signal and no tumour left (TRG1). Conclusion FDG-PET/CT at around 12 weeks after nCRT misses TRG3–4 tumours in 15% and detects residual TRG2–3-4 in 80%. Furthermore, PET-CT detects distant metastases in 10% of patients after nCRT. These data indicate that serial FDG-PET may become valuable in an active surveillance approach. Disclosure All authors have declared no conflicts of interest.

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