Radiolabelled somatostatin analogues detect neuroendocrine tumours (NETs), but may reveal other tumour types. We examined the prevalence of possible meningioma in patients with known or suspected NETs imaged with 68Ga-DOTATATE PET-computed tomography (CT) on the basis of central nervous system uptake and compared with findings on magnetic resonance and contrast-enhanced CT imaging. Retrospective imaging reports from 313 patients who had undergone 68Ga-DOTATATE PET imaging for primary or repeat NET staging were searched to identify suspected meningiomas on PET. Images were then compared with findings on subsequent complementary MRI or contrast-enhanced CT scanning (performed within mean±112 days of PET-CT) if available. Of 313 patients, 22 had regions of uptake suggestive of meningioma. MRI was available for 12 patients and contrast-enhanced CT was available for one patient. Of these, one patient with known von Hippel-Lindau syndrome had probable cerebellar NET metastasis. Six patient scans indicated lesions consistent with PET. Two of these reported initially did not comment on meningioma. No obvious lesion was found in the remaining six patients; however, five showed a possible correlation to venous structures. The mean maximum standardized uptake value±SEM for lesions in all 21 probable meningioma patients was 4.90±0.45. 68Ga-DOTATATE is a sensitive marker of probable meningioma and may identify small lesions not reported on subsequent MRI. Lesions clearly observed on PET were identified on review in half of patients where complementary MR or CT imaging was available. Haemangioblastoma and metastatic NETs may have focal peripheral uptake similar to meningioma on 68Ga-DOTATATE PET and should be considered in the differential.

The development of long axial field of view (LAFOV) positron emission tomography coupled with computed tomography (PET/CT) scanners might be considered the biggest step forward in PET imaging since it became a mainstream clinical modality. Despite increased capital and maintenance costs and data storage requirements, the improvement in image quality, significantly faster acquisition times and lower radiopharmaceutical administered activities, allow a high quality and more efficient clinical service. This step change in technology overcomes some of the limitations of standard short axial field of view scanners. It allows simultaneous imaging of all body systems, and with the ability to obtain high temporal resolution data, it increases potential research applications, particularly in multisystem disease or for dosimetry measurements of novel radiopharmaceuticals. The improvements in sensitivity and signal-to-noise facilitates the use of tracers with long half-lives and low administered activity (e.g. [⁸⁹Zr]-labelled monoclonal antibodies) or very short half-lives (e.g. [⁸²Rb]), opening up applications that hitherto have been challenging. It is early in the evolution of LAFOV PET/CT and the advantages these systems offer have still to be fully realised in providing additional impact in clinical practice. In this article we describe the potential advantages of LAFOV PET technology and some of the clinical and research applications where it has been applied as well as some of the future developments that may enhance the modality further.

Objective To compare the diagnostic interpretation of traditional ventilation/perfusion (V/Q) planar images with that of planar-like images reprojected from single-photon emission computed tomography (SPECT) data sets. Methods Retrospective data from patients who had undergone both planar and SPECT imaging were used to generate anonymized reprojected planar images, which were compared with traditional planar V/Q images. Two consultants interpreted both sets of images for 81 patients following a proforma. We assessed the agreement in the final diagnosis between the two imaging methods and between the two clinicians. We also compared the number, nature, and localization of defects, as well as image quality. Finally, we compared the diagnosis made using planar methods with the original diagnosis made using SPECT. Results There was excellent agreement in diagnosis both between the two planar methods (κ=0.93) and between the two consultants (κ=0.91). Similar numbers of defects were detected, with fewer matched defects being reported in the reprojected group by one of the clinicians. Localization of defects and image quality were similar for the two imaging methods. Six additional pulmonary embolisms were diagnosed using SPECT data. Conclusion We have shown that the performance of reprojected planars from SPECT V/Q was similar to that of traditional planars. These results have potential important implications for patient workflow in busy nuclear medicine departments, as well as for patient comfort.