Usefulness and pitfalls of MAA SPECT/CT in identifying digestive extrahepatic uptake when planning liver radioembolization

International audiencePURPOSE: Identifying gastroduodenal uptake of (99m)Tc-macroaggregated albumin (MAA), which is associated with an increased risk of ulcer disease, is a crucial part of the therapeutic management of patients undergoing radioembolization for liver tumours. Given this context, the use of MAA single photon emission computed tomography (SPECT)/CT may be essential, but the procedure has still not been thoroughly evaluated. The aim of this retrospective study was to determine the effectiveness of MAA SPECT/CT in identifying digestive extrahepatic uptake, while determining potential diagnostic pitfalls. METHODS: Overall, 139 MAA SPECT/CT scans were performed on 103 patients with different hepatic tumour types. Patients were followed up for at least 6 months according to standard requirements. RESULTS: Digestive, or digestive-like, uptake other than free pertechnetate was identified in 5.7% of cases using planar imaging and in 36.6% of cases using SPECT/CT. Uptake sites identified by SPECT/CT included the gastroduodenal region (3.6%), gall bladder (12.2%), portal vein thrombosis (6.5%), hepatic artery (6.5%), coil embolization site (2.1%) as well as falciform artery (5.0%). For 2.1% of explorations, a coregistration error between SPECT and CT imaging could have led to a false diagnosis by erroneously attributing an uptake site to the stomach or gall bladder, when the uptake actually occurred in the liver. CONCLUSION: SPECT/CT is more efficacious than planar imaging in identifying digestive extrahepatic uptake sites, with extrahepatic uptake observed in one third of scans using the former procedure. However, more than half of the uptake sites in our study were vascular in nature, without therapeutic implications. The risk of coregistration errors must also be kept in mind

Application of [68Ga]PSMA PET/CT in Diagnosis and Management of Prostate Cancer Patients

Purpose: The early and accurate diagnosis of locoregional recurrence or metastasis in prostate cancer (PC) has a significant impact on treatment options. Prostatic-specific membrane antigen (PSMA) positron emission tomography (PET)/x-ray computed tomograph (CT) imaging has recently been introduced as a novel procedure in managing PC. The aim of this study was to evaluate the efficacy of [68Ga]PSMA PET/CT in managing PC patients and to compare the detection rate of PET/CT and bone scans (BSs) in detecting bone metastasis. Procedures: We evaluated 415 patients with PC who underwent [68Ga]PSMA PET/CT between March 2015 and September 2018. The patients were classified into three groups: staging, biomedical recurrence (BCR), and follow-up or monitoring, based on the intent to perform PET/CT. Results: We evaluated 415 patients aged 41–99 (68.25 ± 9.59). Of these patients, 344 (82.9 %) had at least one localized lesion. The detection rates were 48.3 %, 52.6 %, 74.4 %, 79.6 %, and 93.9 % for a PSA value of 8, respectively (p 1.16 ng/ml was obtained for PSA value, which equates to specificity of 75 % and sensitivity of 77 %. In comparing BSs and PET/CT, a region-based analysis showed the superiority of PET/CT over BSs for all regions expect the skull (p < 0.05). PET/CT detected 258 suspicious regions, 255 of which were metastatic and three of which were equivocal. BSs detected only 223 suspicious regions, 203 of which were metastatic and 20 of which were equivocal. Conclusions: [68Ga]PSMA PET/CT showed a high detection rate for lesions in PC patients. PSA level, GS, and a PSA doubling time of less than 6 months were shown to be the affective variables. In addition, 68Ga-PSMA PET/CT showed better performance in detecting bone lesions than BSs

Prophylactic Embolization of the Cystic Artery Before Radioembolization: Feasibility, Safety, and Outcomes

PurposeTo evaluate the safety and efficacy of two different methods of proximal cystic artery embolization in patients undergoing yttrium-90 radioembolization.Materials and methodsForty-six patients had cystic artery embolization performed immediately before yttrium-90 radioembolization, either by using Gelfoam pledgets (n = 35) or coils (n = 11). Clinical symptomatology during the admission and angiographic findings at 1-month follow-up were retrospectively reviewed. Rates of collateralization or recanalization of the cystic artery were compared, as well as the frequency of postprocedural abdominal pain and need for cholecystectomy.ResultsTechnical success was achieved in all patients, and there were no procedural complications related to cystic artery embolization. Of the 11 coil-embolized patients, 5 (45%) demonstrated collateralization of the cystic artery at 1 month, and 1 (9%) demonstrated recanalization of the cystic artery. Of the 35 Gelfoam-embolized cases, 2 (6%) had collateralized at 1 month, and 14 (40%) had recanalized. Two patients (one from each group) had self-limited right upper quadrant pain after the procedure, and one patient in the coil embolization group required cholecystectomy.ConclusionProximal cystic artery embolization is safe and feasible and may be performed during liver-directed embolotherapy to minimize the exposure of the gallbladder to particulate, chemoembolic, or radioembolic agents

The enigma of in vivo oxidative stress assessment: isoprostanes as an emerging target

Oxidative stress is believed to be one of the major factors behind several acute and chronic diseases, and may also be associated with ageing. Excess formation of free radicals in miscellaneous body environment may originate from endogenous response to cell injury, but also from exposure to a number of exogenous toxins. When the antioxidant defence system is overwhelmed, this leads to cell damage. However, the measurement of free radicals or their endproducts is tricky, since these compounds are reactive and short lived, and have diverse characteristics. Specific evidence for the involvement of free radicals in pathological situations has been difficult to obtain, partly owing to shortcomings in earlier described methods for the measurement of oxidative stress. Isoprostanes, which are prostaglandin-like bioactive compounds synthesized in vivo from oxidation of arachidonic acid, independently of cyclooxygenases, are involved in many human diseases, and their measurement therefore offers a way to assess oxidative stress. Elevated levels of F2-isoprostanes have also been seen in the normal human pregnancy, but their physiological role has not yet been defined. Large amounts of bioactive F2-isoprostanes are excreted in the urine in normal basal situations, with a wide interindividual variation. Their exact role in the regulation of normal physiological functions, however, needs to be explored further. Current understanding suggests that measurement of F2-isoprostanes in body fluids provides a reliable analytical tool to study oxidative stress-related diseases and experimental inflammatory conditions, and also in the evaluation of various dietary antioxidants, as well as drugs with radical-scavenging properties. However, assessment of isoprostanes in plasma or urine does not necessarily reflect any specific tissue damage, nor does it provide information on the oxidation of lipids other than arachidonic acid

68Ga-DOTATATE and 18F-FDG PET/CT for the Management of Esthesioneuroblastoma of the Sphenoclival Region

We present a 48-year-old woman with an olfactory neuroblastoma who was referred for accurate staging using PET/CT. The 68Ga-DOTATATE PET/CT showed a 51 × 32-mm mass with an SUVmax of 7.59 in the sphenoidal sinuses, whereas radiotracer uptake on 18F-FDG PET/CT was similar to that of brain tissue. 68Ga-DOTATATE PET/CT might be especially useful in regions with difficult tumor visualization resulting from high background, such as brain tissue. The results of this case may suggest that somatostatin receptor imaging in patients with esthesioneuroblastoma may facilitate the potential application of radiotheranostic agents for the treatment of this aggressive subtype of tumors