gallium-ga-68-dotatate and Neoplasms

68Ga-DOTA-SSTRTs PET/CT has become the most promising noninvasive procedure to study well-differentiated NET. Although the excellent diagnostic accuracy of the procedure is well known, its use is limited to specialized centers in Europe as parts of clinical trials. Literature reports confirm the superiority of 68Ga-DOTA-SSTRTs PET/CT for the assessment of well-differentiated NET over morphologic imaging procedures, SRS, and even PET/CT using metabolic radiotracers. 68Ga-DOTA-SSTRTs provide good visualization of NET lesions at both the primary and the metastatic sites (node, bone, liver, and unusual localizations). The advantages of their use over metabolic tracers (18F-DOPA, 18F-FDG) are not only limited to a better overall detection rate but also to the fact that they also provide data on SSTR expression on target lesions, resulting a fundamental procedure before starting therapy with either hot or cold somatostatin analogues. Moreover, they can be used also in centers without an on-site cyclotron. To interpret 68Ga-DOTA-SSTRTs images correctly, it is crucial to understand the tracer’s biodistribution as well as the conditions that may alter tracer uptake. Considering that SSTR are expressed on activated lymphocytes, all areas of inflammation show 68Ga-DOTA-SSTRTs uptake. Areas of increased uptake in frequent sites of inflammation (eg, thyroid, mediastinal nodes, inguinal nodes, and nodes adjacent to areas of recent surgery/trauma) should be interpreted with care. A detailed clinical history with particular attention to concomitant disorders (eg, sarcoidosis, chronic gastritis, chronic thryoiditis) and recent invasive procedures or trauma may often help image interpretation. The presence of uptake in the head of the pancreas should always be carefully evaluated because it may often be benign. Otherwise, because the pancreas is also a frequent site of NET onset, particular attention should be devoted to the evaluation of the uptake pattern (diffuse more likely to be benign) and to the comparison with other imaging techniques.

Topics: Diagnosis, Differential; Gallium Radioisotopes; Humans; Neoplasms; Octreotide; Organometallic Compounds; Positron-Emission Tomography; Radiopharmaceuticals; Receptors, Somatostatin; Tissue Distribution; Tomography, X-Ray Computed

Ectopic adrenocorticotropic hormone (ACTH) secretion is a less common cause of Cushing syndrome and is seen in 5 to 10% of cases with endogenous hypercortisolemia. We hereby describe our experience of patients with ectopic ACTH syndrome, who have been managed over the past 10 years at a tertiary care center in Southern India.. The inpatient and outpatient records of patients from 2006 to 2015 were retrospectively reviewed. The clinical features, clinical history, biochemical values, imaging features, including radiologic findings and positron emission tomography scans, management, details of follow-up, and outcomes, were documented. We compared the biochemical findings in these patients with 20 consecutive patients with Cushing disease (Cushing syndrome of pituitary origin).. A total of 21 patients were studied. The median age at presentation was 34 years (range, 19 to 55 years). Seven patients had thymic carcinoid, 7 had bronchial carcinoid, 3 had lung malignancies, 2 had medullary carcinoma thyroid, 1 patient had a pancreatic neuroendocrine tumor, and 1 patient had an occult source of ACTH. The most common clinical features at presentation were muscle weakness (95%), hyperpigmentation (90%), facial puffiness (76%), easy bruising (61%), edema (57%), and striae (52%). Extensive acne was seen in a large number of patients (43%). Only 3 patients (14%) had central obesity. The median 8 am cortisol was 55.5 μg/dL (range, 3.8 to 131 μg/dL), median 8 am ACTH was 207 pg/mL (range, 31.1 to 703 pg/mL), and the median 24-hour urinary free cortisol was 2,484 μg (range, 248 to 25,438 μg). Basal cortisol and ACTH, as well as midnight cortisol and ACTH level, were markedly higher in patients with ectopic Cushing syndrome as compared to patients with Cushing disease. Twelve of 21 patients had developed life-threatening infections by follow-up. Nine patients had undergone surgical intervention to address the primary tumor. However, only 1 patient exhibited a complete cure on follow-up.. In our series, ectopic Cushing syndrome was most commonly seen in association with intrathoracic tumors such as bronchial or thymic carcinoid. Hyperpigmentation and proximal myopathy were frequent, while central obesity was uncommon. Early and rapid control of hypercortisolemia was important in order to prevent life-threatening infections and metabolic complications.. ACTH = adrenocorticotropic hormone CT = computed tomography DOTATATE =

Topics: Acne Vulgaris; ACTH Syndrome, Ectopic; Adult; Bronchial Neoplasms; Carcinoid Tumor; Carcinoma, Neuroendocrine; Cushing Syndrome; Edema; Female; Humans; Hydrocortisone; Hyperpigmentation; India; Lung Neoplasms; Male; Middle Aged; Muscle Weakness; Neoplasms; Neuroendocrine Tumors; Obesity, Abdominal; Organometallic Compounds; Pancreatic Neoplasms; Positron-Emission Tomography; Radiopharmaceuticals; Retrospective Studies; Tertiary Care Centers; Thymus Neoplasms; Thyroid Neoplasms; Young Adult

The objective of this study is to determine the range of SUVmax of 68Ga-DOTATATE in normal organs and tumoral lesions and establish uptake unrelated to NET.. One hundred and twenty patients (57 men, 63 women), who underwent (68)Ga-DOTATATE PET/CT imaging in our institution were analyzed. Patients were indicated for (68)Ga-DOTATATE PET/CT imaging to detect primary tumor or metastasis of suspected or previously known NET, to determine SSTR positivity and to detect occult source of ectopic Cushing syndrome. Normal range of uptake was calculated for the organs that were proven to have no pathology by either conventional radiological imaging or clinical follow-up, using SUVmax as a semiquantitative measure. Uptake and tumor to background (T/B) ratios of tumoral lesions in liver, pancreas, bone, brain and lymph nodes were calculated. Uptakes due to lesions unrelated to NET were also documented.. Significant uptake was found in spleen, kidneys, adrenal glands, liver and pituitary gland with mean SUVmax of 24.67, 14.30, 13.73, 9.12 and 9.74 respectively. Uptake was measured separately for the pancreatic head and body separately, however, besides a slightly heterogeneous uptake; the difference was not statistically significant. Uptake in the tumoral lesions had high (T/B) ratios with mean SUVmax of 28.72, 25.21, 18.28, 34.73 and 12.59 for liver, pancreas, bone, brain and lymph nodes, respectively. Incidental benign tumoral lesions were detected in 3 patients (2.5 %) which were meningioma and fibrous dysplasia demonstrating significant and breast fibroadenoma demonstrating mild (68)Ga-DOTATATE uptake. Non-neoplastic processes were detected in 4 patients (14.1 %), including postsurgical inflammation, reactive lymph nodes, arthritis and demonstrated faint to mild (68)Ga-DOTATATE uptake, with the exception of significant uptake in accessory spleen.. (68)Ga-DOTATATE has high T/B ratio with physiological biodistribution comparable to its counterparts. However, the presence of SSTRs in benign and malignant lesions unrelated to NET may be challenging in interpretation particularly where the physiological uptake is variable.

Topics: Biological Transport; Female; Humans; Image Interpretation, Computer-Assisted; Male; Neoplasms; Organometallic Compounds; Positron-Emission Tomography; Tomography, X-Ray Computed