Mathieu Gauthé

Role of fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography in gastrointestinal cancers

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a routine imaging modality for many malignancies and its use is currently increasing. In the present review article, we will summarize the evidence for FDG-PET/CT use in digestive cancers (excluding neuroendocrine tumours), and review the existing recommendations. While PET/CT is nowadays considered to be an important tool in the initial workup of oesophageal and anal cancers, new data are emerging regarding its use in assessing therapeutic efficacy, radiotherapy treatment planning, and detection of recurrence in case of isolated tumour marker elevation. Moreover, PET/CT may help decision making by detecting distant metastatic sites especially in potentially resectable metastatic colorectal cancer and, to a lesser extent, in localized gastric and pancreatic cancers. Finally, incidental focal colonic FDG uptakes require exploration by colonoscopy, as they are often associated with premalignant or malignant lesions.

Diagnosis of sinusoidal obstruction syndrome by positron emission tomography/computed tomography: Report of two cases treated by defibrotide

Sinusoidal obstruction syndrome (SOS) is a potentially fatal liver injury that mainly occurs after myeloablative chemotherapy. We report two cases of SOS investigated by 18F‐fluorodeoxyglucose positron emission tomography/computed tomography and treated with defibrotide. (Hepatology 2014;60:1789–1791)

Incidental scintigraphic finding of ovarian teratoma containing normal thyroid tissue on post-radioactive iodine therapy for papillary thyroid cancer.

Abnormal focal uptakes are often visualized on I post-treatment scintigraphy in case of differentiated thyroid carcinoma. For some of these, especially on atypical localization, it can be difficult to affirm the benign or malignant nature. A high serum thyroglubulin value after surgery may suggest the presence of metastatic disease. We report a case of an abnormal ovarian uptake on post-treatment scintigraphy associated with an elevated thyroglobulin value revealing finally an ovarian mature cystic teratoma containing normal thyroid tissue.

18F-Fluorocholine PET/CT of Incidental Male Breast Cancer.

Breast cancer is approximately 100 times less common among men. Estrogen-related receptor α was detected in human prostate cancer tissue, and androgen receptors are expressed in both normal and malignant breast tissue. Thus, prostate cancer hormonal therapy may increase breast cancer risk. A 67-year-old man with prostate cancer history presented with rising prostate-specific antigen level. F-Fluorocholine PET/CT showed intense uptake in his right breast and moderate uptake in right axillary lymph node. Complementary F-FDG PET/CT demonstrated more intense tracer uptakes in both the right breast and axillary lymph node. Breast histological findings were invasive ductal cancer, with axillary lymph node invasion.

Uterine leiomyosarcoma metastatic to thyroid shown by 18F-FDG PET/CT imaging

About one third of focal thyroid uptakes in a fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) study are malignant, the most frequent histological type being papillary carcinoma. Metastases to the thyroid account for approximately 7.5% of thyroid malignancies and come mainly from kidney, lung, head and neck, and breast cancers. We report the case of a 64-year-old woman presenting a fast growing thyroid nodule whose primitive or metastatic origin was not obvious, for which 18F-FDG PET/CT helped in the diagnostic process and in the later management of the patient. Histopathologic findings finally revealed a metastasis of uterine leiomyosarcoma.

Primary Neuroendocrine Tumor in a Horseshoe Kidney With Positive 111In-Pentetreotide Somatostatin Receptor Scintigraphy and Negative 18F-DOPA PET/CT.

Primary renal neuroendocrine tumors (NETs) are low-grade tumors with neuroendocrine differentiation and have been reported to arise most commonly in renal abnormalities such as horseshoe kidney. We report a case of a 54-year-old woman with history of invasive ductal breast carcinoma presenting several liver lesions. Histological findings finally revealed liver locations of a well-differentiated NET. Imaging workup combining somatostatin receptor scintigraphy and F-DOPA PET/CT finally enable proper diagnosis of primary renal NET located on the isthmus of a horseshoe kidney.

Visualization of Macroprolactinoma by 18F-Fluorocholine PET/CT in a Patient With Multiple Endocrine Neoplasia Type 1

Department of Endocrinology, CochinHospital, Assistance PubliqueHôpitaux de Paris, Paris Descartes University, 75014 Paris, France; Department of Endocrine Surgery, Cochin Hospital, Assistance Publique Hôpitaux de Paris, Paris Descartes University, 75014 Paris, France; Department of Nuclear Medicine, Cochin Hospital, Assistance Publique Hôpitaux de Paris, Paris Descartes University, 75014 Paris, France; and Department of Nuclear Medicine, Tenon Hospital, Assistance Publique Hôpitaux de Paris, 75020 Paris, France

Vertebral metastases from neuroendocrine tumours: How to avoid false positives on 68 Ga-DOTA-TOC PET using CT pattern analysis?

ObjectivesTo develop criteria to improve discrimination between vertebral metastases from neuroendocrine tumours (NETs) and benign bone lesions on PET combined with CT using DOTA-D-Phe1-Tyr3-octreotide labelled with gallium-68 (68Ga-DOTA-TOC).MethodsIn 535 NET patients, 68Ga-DOTA-TOC PET/CT examinations were reviewed retrospectively for vertebral CT lesions and/or PET foci. For each vertebral PET abnormality, appearance on CT, biological volume (BV), standardized uptake value (SUVmax) and ratios to those of reference organs were determined. All vertebral abnormalities were characterized as a metastasis, a typical vertebral haemangioma (VH) or other benign lesion.ResultsIn 79 patients (14.8 %), we found 107 metastases, 34 VHs and 31 other benign lesions in the spine. The optimal cut-off values to differentiate metastases from benign lesions were BV ≥0.72 cm3, SUVmax ≥2, SUVmax ratio to a reference vertebra ≥2.1, to liver ≥0.28 and to spleen ≥0.14. They corresponded to lesion-based 68Ga-DOTA-TOC PET/CT sensitivity of 87 %, 98 %, 97 %, 99 % and 94 %, and specificity of 55 %, 100 %, 90 %, 97 %, 100 %, respectively.ConclusionsThe high sensitivity of 68Ga-DOTA-TOC-PET/CT in detecting NET vertebral metastases was confirmed; this study showed that specificity could be improved by combining CT features and quantifying 68Ga-DOTA-TOC uptake.Key Points• Bone metastases in neuroendocrine tumours correlate with prognosis.• Benign bone lesions may mimic metastases on68Ga-DOTA-TOC PET/CT imaging.• The specific polka-dot CT pattern may be missing in some vertebral haemangiomas.• Lesion atypical for haemangiomas can be better characterized by quantifying68Ga-DOTA-TOC uptake.

Une innovation dans l’imagerie du cancer de la prostate : la tomographie par émission de positons

L’imagerie utilisant la tomographie par emission de positons (TEP) dans le cadre du cancer de la prostate (CP) n’est pas mentionnee ou est meme deconseillee dans la plupart des referentiels actuels des societes savantes, sauf ceux du National Comprehensive Cancer Network (NCCN) aux Etats-Unis. Cela est contraire a l’evolution des recommandations pour l’imagerie de la plupart des autres cancers. La cause principale est la moindre performance dans le CP du traceur TEP le plus repandu : le [18F] fluorodesoxyglucose (FDG). D’autres traceurs sont donc a considerer comme des innovations, meme si deux d’entre eux, le fluorure de sodium (FNa) et la fluorocholine (FCH), ont deja une autorisation de mise sur le marche (AMM) en France. Ils sont utiles pour deceler les metastases osseuses et aussi, dans le cas de la FCH, les recidives locales, ganglionnaires et a distance dans les parties molles. La FCH permet aussi le suivi therapeutique rapproche au stade de CP resistant a la castration. Depuis quelques annees, de nouveaux traceurs innovants sont en cours d’evaluation avec des performances diagnostiques qui seraient, selon des etudes pilotes, superieures a celles de la FCH. Cet article fait le point sur les resultats de la TEP dans les divers stades du CP, en se limitant aux traceurs innovants dont l’emploi chez l’homme a ete rapporte.

Differential diagnosis of trampoline fracture from osteomyelitis by bone scan with pinhole collimator

Abstract A 2-year-old girl with recent history of trampoline fall presented to the A&E Department for complete functional impairment of the left lower extremity and fever. Blood examination revealed an inflammatory syndrome, while plain radiographs were normal. As magnetic resonance imaging was unavailable, a bone scintigraphy was performed. While standard acquisition found an intense uptake focused on the left proximal tibial metaphysis whose appearance was suggestive of acute hematogenous osteomyelitis, complementary acquisition with the pinhole collimator demonstrated that this abnormal uptake was clearly distinct from the cartilage growth plate. One month follow-up radiographs showed a fracture that confirmed the diagnosis of trampoline fracture.