BACKGROUND AND PURPOSE: Aneurysmal subarachnoid hemorrhage is a life-threatening condition associated with angiographic vasospasm, delayed cerebral ischemia, and other complications that may lead to significant morbidity and mortality. Our study evaluated associations of vessel wall enhancement on intracranial vessel wall MRI with rupture status, and predictive value of vessel wall enhancement, conventional imaging, and clinical features for angiographic vasospasm, delayed cerebral ischemia, which encompasses delayed infarction and symptomatic vasospasm. MATERIALS AND METHODS: A retrospective cohort study included patients who underwent endovascular treatment for ruptured or unruptured intracranial aneurysms with immediate post-intervention vessel wall MRI between November 2015 and August 2022. Logistic regression models were used to assess the relationship of vessel wall enhancement with SAH, angiographic vasospasm, and a composite of delayed cerebral ischemia, delayed infarction, and symptomatic vasospasm after adjustment for clinical and traditional imaging factors. We used adjusted vessel wall enhancement segments as a qualitative variable, defined as the proportion of enhanced vessel segments relative to the total number of evaluable segments per patient. RESULTS: Among 128 patients (79 ruptured, 49 unruptured), adjusted vessel wall enhancement was significantly higher among patients with ruptured than unruptured aneurysms (OR=1.62, 95%CI=1.39–1.99, p<0.001). In the rupture cohort, adjusted vessel wall enhancement was the only independent predictor of angiographic vasospasm (OR=1.12, 95%CI=1.03–1.23, p=0.01). In contrast, the modified Fisher grade and hypertension were independent predictors of delayed cerebral ischemia (p<0.05), whereas adjusted vessel wall enhancement was not. CONCLUSIONS: Qualitative adjusted vessel wall enhancement is associated with SAH and is a reliable, independent predictor of angiographic vasospasm, but is not predictive of delayed cerebral ischemia. Given the multifactorial nature of SAH-related complications, integrating vessel wall enhancement with conventional imaging and clinical factors may improve risk stratification and predictive assessment. ABBREVIATIONS: aSAH= Aneurysmal Subarachnoid Hemorrhage. ASVWE= Adjusted Segmental Vessel Wall Enhancement. DCI= Delayed Cerebral Ischemia. DI= Delayed Infarction. IA= Intracranial Aneurysm. IVWM= Intracranial Vessel Wall MRI. mFisher= Modified Fisher Grade. OR=Odds Ratio. VWE= Vessel Wall Enhancement.

Complications of aneurysmal subarachnoid hemorrhage (aSAH), including vasospasm and delayed cerebral ischemia (DCI) substantially contribute to morbidity and mortality. We investigated the correlation between quantitative measurements on MRA performed immediately post-endovascular embolization and subsequent development of DCI or vasospasm. We included consecutive patients scanned between 9/1/2016 and 1/14/2022 with ruptured intracranial aneurysms (IAs) after endovascular treatment. We recorded clinical data including sex, age, BMI, smoking history, vascular risk factors, baseline CTA/CT features, modified Fisher score, and Glasgow Coma Score. We extracted quantitative MRA features, including total arterial length, total branch number, and average tortuosity, using a custom semi-automated software (VesselVoyager). Correlations between baseline quantitative MRA, other imaging and clinical features with DCI and vasospasm were determined using logistic regression analysis. Receiver operating characteristic (ROC) curves were calculated for clinical-only models and for models augmented with quantitative MRA features. 78 patients with ruptured IAs were included, of whom 48 developed vasospasm and 24 developed DCI. Multivariable logistic regression analysis showed that only average tortuosity was significantly and independently associated with subsequent DCI (OR 0.62, 95% CI 0.39-0.91, p=0.02). For vasospasm, total arterial length (0.87, 0.78-0.95, p=0.005), average tortuosity (0.37, 0.18-0.62, p=0.001), and age (0.92, 0.86-0.98, p=0.02) were independently associated with vasospasm incidence on multivariable regression. Adding quantitative MRA features improved ROC performance for both DCI (AUC 0.63 [95% CI 0.51-0.75])vs 0.75 [0.64-0.87]) and vasospasm (0.67 [0.54-0.79] vs 0.85 [0.77-0.94]). In patients with aSAH, average tortuosity is independently inversely associated with future development of DCI. Total branch number and average tortuosity are independently inversely associated with future vasospasm. With further validation, quantitative MRA features may serve as predictive markers for DCI and vasospasm after aSAH.

Gallbladder neuroendocrine tumors (GB-NETs) are rare, accounting for <0.5% of all NETs, and little is known about somatostatin receptor expression (SSTR) and its response to SSTR-targeted treatment such as Lutetium-177 ( ¹⁷⁷ Lu) DOTATATE. ⁶⁸ Ga DOTATATE PET/CT is a valuable imaging modality for SSTR expression and ¹⁷⁷ Lu DOTATATE treatment planning. We present a case of a 74-year-old man with recurrent WHO grade 3 GB-NET. ¹⁷⁷ Lu DOTATATE failed to control hepatic metastases despite high DOTATATE uptake, which led to treatment discontinuation. This case highlights the fact that positive SSTR imaging in GB-NETs does not always lead to a favorable response to ¹⁷⁷ Lu DOTATATE.

Background: Quantitative amyloid PET is increasingly used in clinical practice, but the interchangeability of quantification software remains uncertain. We compared quantitative amyloid PET measurements, diagnostic performance, and platform-specific thresholds between two FDA-cleared software packages, MIMneuro and Neurophet SCALE PET, using clinical Florbetapir ¹⁸ F-PET/CT. Patients and Methods: In this retrospective single-center study, 95 consecutive patients who underwent Florbetapir ¹⁸ F-PET/CT were independently analyzed using MIMneuro and Neurophet SCALE PET. Quantitative measures included standardized uptake value ratios (SUVRs) and global Centiloid values. Cross-platform agreement was evaluated using Pearson correlation, Bland–Altman analysis, and Cohen κ statistics. Receiver operating characteristic analysis was used to determine platform-specific thresholds for predicting visual amyloid positivity. Results: Regional SUVRs showed moderate correlations ( r = 0.414 to 0.674; all P < 0.001), with the strongest correlation observed for global Centiloid values ( r = 0.684). Neurophet yielded significantly higher global SUVR values than MIMneuro (mean bias, −0.20; P < 0.001), whereas the difference in Centiloid values was not significant. The optimal thresholds for predicting visual amyloid positivity were 1.10 versus 1.40 for global SUVR and 20.7 versus 34.4 for global Centiloids for MIMneuro and Neurophet, respectively. Cross-platform agreement was moderate using SUVR (κ = 0.42) and improved with Centiloids (κ = 0.60). Conclusions: Although MIMneuro and Neurophet SCALE PET showed moderate agreement, their quantitative measurements were not directly interchangeable at clinically relevant thresholds. These findings suggest that platform-specific quantitative thresholds may be needed when amyloid PET is used for clinical interpretation, longitudinal follow-up, or selection of patients for antiamyloid therapy.