The Calcium Versus Hemorrhage Trial: Developing Diagnostic Criteria for Chronic Intracranial Susceptibility Lesions Using Single-Energy Computed Tomography, Dual-Energy Computed Tomography, and Quantitative Susceptibility Mapping

PURPOSE

Chronic susceptibility lesions in the brain can be either hemorrhagic (potentially dangerous) or calcific (usually not dangerous) but are difficult to discriminate on routine imaging. We proposed to develop quantitative diagnostic criteria for single-energy computed tomography (SECT), dual-energy computed tomography (DECT), and quantitative susceptibility mapping (QSM) to distinguish hemorrhage from calcium.

MATERIALS AND METHODS

Patients with positive susceptibility lesions on routine T2*-weighted magnetic resonance of the brain were recruited into this prospective imaging clinical trial, under institutional review board approval and with informed consent. The SECT, DECT, and QSM images were obtained, the lesions were identified, and the regions of interest were defined, with the mean values recorded. Criteria for quantitative interpretation were developed on the first 50 patients, and then applied to the next 45 patients. Contingency tables, scatter plots, and McNemar test were applied to compare classifiers.

RESULTS

There were 95 evaluable patients, divided into a training set of 50 patients (328 lesions) and a validation set of 45 patients (281 lesions). We found the following classifiers to best differentiate hemorrhagic from calcific lesions: less than 68 Hounsfield units for SECT, calcium level of less than 15 mg/mL (material decomposition value) for DECT, and greater than 38 ppb for QSM. There was general mutual agreement among the proposed criteria. The proposed criteria outperformed the current published criteria.

CONCLUSIONS

We provide the updated criteria for the classification of chronic positive susceptibility brain lesions as hemorrhagic versus calcific for each major clinically available imaging modality. These proposed criteria have greater internal consistency than the current criteria and should likely replace it as gold standard.

Hyperpolarized Pyruvate MR Spectroscopy Depicts Glycolytic Inhibition in a Mouse Model of Glioma

BackgroundA generation of therapies targeting tumor metabolism is becoming available for treating glioma. Hyperpolarized MRI is uniquely suited to directly measure the metabolic effects of these emerging treatments.PurposeTo explore the feasibility of the use of hyperpolarized [1-carbon 13 {¹³C}]-pyruvate for real-time measurement of metabolism and response to treatment with a glycolytic inhibitor in an orthotopic mouse model of glioma.Materials and MethodsIn this animal study, anatomic MRI and dynamic ¹³C MR spectroscopy were performed at 7 T during intravenous injection of hyperpolarized [1-¹³C]-pyruvate on mice with orthotopic U87MG glioma and healthy control mice. Anatomic MRI and dynamic ¹³C MR spectroscopy were repeated after administration of the glycolytic inhibitor WP1122, a prodrug of 2-deoxy-d-glucose. All experiments were conducted in athymic nude mice between October 2016 and March 2017. Hyperpolarized lactate production was quantified as an apparent reaction rate, or k_PL, and normalized lactate ratio (nLac). The Wilcoxon signed-rank test was used to assess changes in paired measures of lactate production before and after treatment.ResultsThirteen 12-16-week-old female mice and five healthy female mice underwent anatomic MRI and hyperpolarized [1-¹³C]-pyruvate spectroscopy. Large contrast agent-enhanced tumors were shown in mice with glioma at T2-weighted and T1-weighted postcontrast MRI by postimplantation day 40. After treatment with WP1122, a decrease in lactate was observed in mice with glioma (baseline and treatment mean k_PL, 0.027 and 0.018 sec^-1, respectively, P = .01; baseline and posttreatment mean nLac, 0.28 and 0.22, respectively, P = .01) whereas no significant decrease was observed in healthy control mice (baseline and posttreatment mean k_PL, 0.011 and 0.017 sec^-1, respectively, P = .91; baseline and posttreatment mean nLac, 0.16 and 0.21, respectively, P = .84).ConclusionHyperpolarized carbon 13 measurements of pyruvate metabolism can provide rapid feedback for monitoring treatment response in glioma.© RSNA, 2019.

Abstract 5260: Prevention of oxaliplatin-induced neuropathy by using minocycline as a chemoprotectant: demonstration by imaging and behavioral assessment

Purpose: To utilize neurography, a novel imaging method based on retrograde transport of a molecular nerve imaging tracer, to assess the protective effect of minocycline on the development of Oxaliplatin-induced neuropathy.

Materials and Methods: Female BALB/c mice received one of four treatments vehicle/vehicle, vehicle/minocycline, Oxaliplatin/vehicle, or Oxaliplatin/minocycline (n = 8/group). A 30 mg/kg cumulative dose of Oxaliplatin or dextrose vehicle was given in 10 divided intra-peritoneal doses across 3 weeks using two 5 days cycles. Animals were treated daily with 50 mg/kg minocycline or 0.9% saline vehicle by oral gavage beginning 48 h prior to the first Oxaliplatin treatment. Both imaging and behavioral data were collected at baseline and weekly for 3 weeks. For each imaging session, animals received fluorescently labeled TTc-Alexa790 (15 ug/20 uL) via intramuscular injection into the calf muscles. Fluorescent imaging (Xenogen IVIS 200) was used to image the distribution of TTc over 60 minutes, with ROI measurements taken over the lumbo-thoracic junction of the spine to quantitate fluorescent uptake. Neurobehavioral assessment for mechanical sensitivity was assessed through the use of von Frey nylon filaments to exert calibrated force on the footpads. The 50% hind paw withdrawal threshold was calculated.

Results: Oxaliplatin/vehicle treated animals showed a significant decrease in transport of TTc during the second week of treatment (F (1,12) = 39.604, p<0.001), while the TTc transport of the vehicle/vehicle and oxaliplatin/minocycline remained stable across the experiment. The vehicle/minocycline group saw an increase in transport of TTc during the second week of treatments (F (1,12) = 42.533, p<0.001). Behavioral data indicated that Oxaliplatin treatment resulted in increased mechanical sensitivity, while minocycline treatment abrogated this effect, such that animals in the Oxaliplatin/vehicle group showed increased sensitivity compared to all other groups. This effect emerged within the first week of treatment and remained throughout the study. A linear correlation between paw withdrawal threshold and TTc transport at week 3 was found, with r = 0.7939, p<0.01, such that subjects with reduced TTc transport also displayed reduced mechanical thresholds.

Conclusion: Oxaliplatin causes a decrease in retrograde axonal transport, and this reduction in transport correlates with neurobehavioral impairment due to neuropathy. We show that this effect can be attenuated by a chemo-protectant, minocycline, and that the protectant effect was apparent with both behavioral and imaging readouts. This suggests that minocycline can prevent the neuropathy induced by Oxaliplatin and that the mechanism of both the pathological effect and its prevention are related to retrograde axonal transport.

Citation Format: Dawid Schellingerhout, Elizabeth Vichaya, Leo G. Flores, Daniela Ramos, Lucia Le Roux. Prevention of oxaliplatin-induced neuropathy by using minocycline as a chemoprotectant: demonstration by imaging and behavioral assessment. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5260.