All tumors were histologically well/moderately differentiated and 37/51/3/10 were G1/G2/G3/Unknown, respectively. Results: Among 101 patients, 51/50 were female/male, tumor origins were gastroenteropancreatic (GEP) (75%), Unknown Primary (UP) (13%), lung (8%), thymic (2%), and other (2%). Imaging was reviewed and compared to prior available CT, MRI, and/or In-111 Pentetreotide scans. Methods: Consecutive patients diagnosed with NETs and referred to our institution who received an initial Ga-68 Dotatate PET/CT between 07/2017-09/2018 were included. We describe the impact of initial NETSPOT imaging on diagnosis and management in NET patients at a large urban medical center. The effect of this novel imaging modality on US clinical practice and its usefulness in different types of NETs is not well described. Key pointsīenign hepatic adenomas may be FDG-avid and a cause of a false positive finding for malignancy.Background: Somatostatin analogue functional imaging with Ga-68 Dotatate PET/CT has demonstrated superiority in lesion detection in patients with NETs. Since 111In-DTPA-octreotide has higher affinity for SSTR-2A, while 68Ga-DOTATATE has high affinity for both SSTR-2A and SSTR-2B, this might explain the incidental finding on NETSPOT exam but lack of it on octreoscan. Presence of unlabeled somatostatin, either because of octreotide therapy or resulting from production of somatostatin by the neuroendocrine tumor. Presence of different somatostatin receptor subtypes that have different affinities for the radioligand Two potential reasons for false-negative results on octreoscan are (9) Since meningiomas have a tendency to local osseous invasiveness, this unique capability of PET/CT is particularly helpful for evaluating meningiomas of the skull base where biopsy has a high risk of hemorrhage and the findings of CT and MRI are often unclear (8). Even though many studies have reported 100% sensitivity of detecting all meningioma lesions, a major drawback of 111In-octreotide SPECT is its difficulty in detecting meningiomas with a diameter <2.7 cm or a volume <10 mL (6).Ħ8Ga-DOTATATE PET/CT offers high-contrast images of meningiomas measuring as small as 7-8 mm in diameter and can also be clearly separated from both surrounding brain and bone tissue (7).

111In-DTPA-octreotide binds with high affinity to SSTR2, SSTR3, and SSTR5 overexpression of the SSTR2A receptor may explain the high tracer uptake observed in meningiomas (5). There are two isoforms of SST-2: SSTR-2A and SSTR-2B. There are 5 different subtypes of SSTRs, of which Subtype 2 is most often expressed on the surface (3, 4). Somatostatin receptors (SSTRs) are expressed on the cell membrane of various central nervous and peripheral tissues in high density to a varying extent, including neuroendocrine tumors and intracranial tumors (2). Nuclear medicine studies-SPECT and PET-could provide complementary information to CT and MRI. Conventional imaging modalities like CT and MRI are part of the routine diagnostic workup of patients who are being evaluated for meningiomas. They arise from the meningothelial cells of the arachnoid membranes. Meningiomas are the most common primary intracranial neoplasms and represent about 36.1% of all intracranial tumors (1). A contrast-enhancing, dural-based mass is seen in the right superior frontal lobe, most consistent with meningioma. Coronal slice of T1-weighted brain MRI with contrast image.

Incidental uptake is visualized in the right superior frontal lobe. Figure 2C: Non-enhanced CT and fused PET/CT axial images confirm anatomic location of the hyperdense/tracer-avid focus. Physiological tracer distribution is seen in the pituitary gland, spleen, adrenal glands, kidney and urinary bladder. Findingsįigure 1: Anterior and posterior whole body planar imaging using octreoscan (111In- DTPA-octreotide). Figure 2A: MIP image of the 68Ga-DOTATATE. This was further confirmed on dedicated MRI with contrast of the brain which found a 1.5 x 1.3 x 1.2 cm avidly enhancing, dural-based mass in the right superior frontal lobe consistent with meningioma (Figure 3). Patient subsequently underwent NETSPOT (68Ga DOTATATE) PET/CT imaging in November 2017, which reported an incidental focus of intense uptake in the right superior frontal lobe (Figure 2). Similarly, follow-up CT arterial portography (AP) done in 2015 and octreoscan (111In-DTPA-octreotide) done in May 2017 reported no disease recurrence (Figure 1). This patient was diagnosed with an exophytic GIST tumor in 2013 (images not available) and underwent surgical resection and had follow-up 18F-FDG PET/CT in 2014 to evaluate for recurrence/relapse, which reported no recurrent/residual disease.

Netspot pet