Our objective was to evaluate the association of arterial 18 F-FDG uptake and calcifications in large arteries as detected by 18 F-FDG PET/CT with the subsequent occurrence of vascular events in otherwise asymptomatic cancer patients. Methods: Clinical follow-up information was obtained for 932 cancer patients examined with whole-body 18 F-FDG PET/CT (median follow-up time, 29 mo). Among this cohort, 279 patients had died from their oncologic disease. In 15 of 932 patients (1.6%), a vascular event, defined as ischemic stroke, myocardial infarction, or revascularization, was registered. The maximal standardized uptake value (SUV) was divided by the blood-pool SUV, yielding a target-to-background ratio (TBR) for each arterial segment. The mean TBR as well as a calcified plaque sum score per patient were calculated in the major vessels: ascending, descending, and abdominal aorta, aortic arch, as well as iliac and carotid arteries. Results: A significant correlation was observed between mean TBR and calcified plaque sum (P , 0.001). Although calcified plaque sum significantly correlated with all conventional risk factors for vascular events, mean TBR correlated only with age, the male sex, and hypertension. The Cox regression hazard model identified a mean TBR $ 1.7 and a calcified plaque sum $ 15 as independent predictors for the occurrence of a vascular event. Patients with both mean TBR and calcified plaque sum above these thresholds were identified as having the highest risk for a future vascular event. However, a mean TBR $ 1.7 had greater prognostic value than did a calcified plaque sum $ 15. Conclusion: In a large cohort of cancer patients, increased 18 F-FDG uptake in major arteries emerged as the strongest predictor of a subsequent vascular event. Concomitant severe vascular calcifications seemed to impart a particularly high risk. Given the small event rate in the present study, larger, prospective trials of patients without cancer are required to substantiate these promising results.

This pilot study suggests that arterio-arterial embolism from complicated, nonstenosing carotid atherosclerotic plaques may play a role in a subgroup of patients previously diagnosed with cryptogenic stroke. To further evaluate the significance of AHA type VI plaques in cryptogenic stroke, future studies will have to analyze both clinical and imaging follow-up data, including event rates for secondary strokes.

No abstract

Ga-DOTATATE PET/CT enables detection of meningioma tissue based on somatostatin receptor 2 expression. Transosseous extension of intracranial meningiomas is known to be an important risk factor for tumor recurrence and patient mortality. We analyzed the diagnostic performance of Ga-DOTATATE PET/CT and contrast-enhanced MRI (CE-MRI) for the detection of osseous infiltration using qualitative and quantitative imaging parameters. In this institutional review board-approved retrospective study, subjects were selected from 327 consecutive Ga-DOTATATE PET/CT examinations for evaluation of confirmed or suspected meningioma. Inclusion criteria were CE-MRI within 30 d and pathology-confirmed meningioma diagnosis with inclusion or exclusion of transosseous extension as the standard of reference. Imaging was analyzed by two readers. Tracer uptake values and meningioma volumes were determined. χ, Mann-Whitney U, Wilcoxon signed rank, and McNemar tests, as well as receiver-operating-characteristic analyses, were performed to compare variables and diagnostic performance. Eighty-two patients fulfilled the inclusion criteria. Patients with transosseous extension of meningioma ( = 67) showed significantly larger lesions (median, 12.8 vs. 3.3 mL; < 0.001) and significantly higher tracer uptake values (median SUV, 14.2 vs. 7.6; = 0.011) than patients with extraosseous meningiomas ( = 15). Ga-DOTATATE PET/CT in comparison to CE-MRI performed at a higher sensitivity (98.5% vs. 53.7%) while maintaining high specificity (86.7% vs. 93.3%) in the detection of osseous involvement ( < 0.001). In receiver-operating-characteristic analysis, PET/CT assessment performed better than CE-MRI (area under the curve, 0.932 vs. 0.773). PET/CT- and CE-MRI-based volume estimation yielded comparable results for extraosseous meningiomas ( = 0.132) and the extraosseous part of transosseous meningiomas ( = 0.636), whereas the volume of the intraosseous part was assessed as significantly larger by PET/CT ( < 0.001). Ga-DOTATATE PET/CT enables improved detection of the transosseous extension of intracranial meningiomas compared with CE-MRI.

No abstract

The tumor-homing property of mesenchymal stem cells (MSCs) allows targeted delivery of therapeutic genes into the tumor microenvironment. The application of sodium iodide symporter (NIS) as a theranostic gene allows noninvasive imaging of MSC biodistribution and transgene expression before therapeutic radioiodine application. We have previously shown that linking therapeutic transgene expression to induction of the chemokine CCL5/ RANTES allows a more focused expression within primary tumors, as the adoptively transferred MSC develop carcinoma-associated fibroblast-like characteristics. Although RANTES/CCL5-NIS targeting has shown efficacy in the treatment of primary tumors, it was not clear if it would also be effective in controlling the growth of metastatic disease. Methods: To expand the potential range of tumor targets, we investigated the biodistribution and tumor recruitment of MSCs transfected with NIS under control of the RANTES/ CCL5 promoter (RANTES-NIS-MSC) in a colon cancer liver metastasis mouse model established by intrasplenic injection of the human colon cancer cell line LS174t. RANTES-NIS-MSCs were injected intravenously, followed by 123 I scintigraphy, 124 I PET imaging, and 131 I therapy. Results: Results show robust MSC recruitment with RANTES/CCL5-promoter activation within the stroma of liver metastases as evidenced by tumor-selective iodide accumulation, immunohistochemistry, and real-time polymerase chain reaction. Therapeutic application of 131 I in RANTES-NIS-MSC-treated mice resulted in a significant delay in tumor growth and improved overall survival. Conclusion: This novel gene therapy approach opens the prospect of NIS-mediated radionuclide therapy of metastatic cancer after MSC-mediated gene delivery.

[(18)F]FDG PET is able to identify with high sensitivity the presence of osteomyelitis in orthopaedic surgery patients with nonspecific clinical symptoms of infection.

BackgroundPreviously proposed classifications for carotid plaque and cerebral parenchymal hemorrhages are used to estimate the age of hematoma according to its signal intensities on T1w and T2w MR images. Using these classifications, we systematically investigated the value of cardiovascular magnetic resonance (CMR) in determining the age of vessel wall hematoma (VWH) in patients with spontaneous cervical artery dissection (sCAD).Methods35 consecutive patients (mean age 43.6 ± 9.8 years) with sCAD received a cervical multi-sequence 3T CMR with fat-saturated black-blood T1w-, T2w- and TOF images. Age of sCAD was defined as time between onset of symptoms (stroke, TIA or Horner's syndrome) and the CMR scan. VWH were categorized into hyperacute, acute, early subacute, late subacute and chronic based on their signal intensities on T1w- and T2w images.ResultsThe mean age of sCAD was 2.0, 5.8, 15.7 and 58.7 days in patients with acute, early subacute, late subacute and chronic VWH as classified by CMR (p < 0.001 for trend). Agreement was moderate between VWH types in our study and the previously proposed time scheme of signal evolution for cerebral hemorrhage, Cohen's kappa 0.43 (p < 0.001). There was a strong agreement of CMR VWH classification compared to the time scheme which was proposed for carotid intraplaque hematomas with Cohen's kappa of 0.74 (p < 0.001).ConclusionsSignal intensities of VWH in sCAD vary over time and multi-sequence CMR can help to determine the age of an arterial dissection. Furthermore, findings of this study suggest that the time course of carotid hematomas differs from that of cerebral hematomas.