Ultra-low dose chest CT with silver filter and deep learning reconstruction significantly reduces radiation dose and retains quantitative information in the investigation and monitoring of lymphangioleiomyomatosis (LAM)

PURPOSE

Frequent CT scans to quantify lung involvement in cystic lung disease increases radiation exposure. Beam shaping energy filters can optimize imaging properties at lower radiation dosages. The aim of this study is to investigate whether use of SilverBeam filter and deep learning reconstruction algorithm allows for reduced radiation dose chest CT scanning in patients with lymphangioleiomyomatosis (LAM).

MATERIAL AND METHODS

In a single-center prospective study, 60 consecutive patients with LAM underwent chest CT at standard and ultra-low radiation doses. Standard dose scan was performed with standard copper filter and ultra-low dose scan was performed with SilverBeam filter. Scans were reconstructed using a soft tissue kernel with deep learning reconstruction (AiCE) technique and using a soft tissue kernel with hybrid iterative reconstruction (AIDR3D). Cyst scores were quantified by semi-automated software. Signal-to-noise ratio (SNR) was calculated for each reconstruction. Data were analyzed by linear correlation, paired t-test, and Bland-Altman plots.

RESULTS

Patients averaged 49.4 years and 100% were female with mean BMI 26.6 ± 6.1 kg/m2. Cyst score measured by AiCE reconstruction with SilverBeam filter correlated well with that of AIDR3D reconstruction with standard filter, with a 1.5% difference, and allowed for an 85.5% median radiation dosage reduction (0.33 mSv vs. 2.27 mSv, respectively, p < 0.001). Compared to standard filter with AIDR3D, SNR for SilverBeam AiCE images was slightly lower (3.2 vs. 3.1, respectively, p = 0.005).

CONCLUSION

SilverBeam filter with deep learning reconstruction reduces radiation dosage of chest CT, while maintaining accuracy of cyst quantification as well as image quality in cystic lung disease.

CLINICAL RELEVANCE STATEMENT

Radiation dosage from chest CT can be significantly reduced without sacrificing image quality by using silver filter in combination with a deep learning reconstructive algorithm.

KEY POINTS

• Deep learning reconstruction in chest CT had no significant effect on cyst quantification when compared to conventional hybrid iterative reconstruction. • SilverBeam filter reduced radiation dosage by 85.5% compared to standard dose chest CT. • SilverBeam filter in coordination with deep learning reconstruction maintained image quality and diagnostic accuracy for cyst quantification when compared to standard dose CT with hybrid iterative reconstruction.

Abstract 2575: Results from the first-in-human phase I trials of recombinant human Interleukin 15 (rhIL-15) administered as a daily 30 minute intravenous infusion (IVB) for 12 consecutive days or as continuous intravenous infusion (CIV) for 240 hours in patients with refractory metastatic cancers

Preclinical laboratory experiments with Interleukin 15 (IL-15) have demonstrated significant immunotherapeutic potential for recombinant human IL-15 (rhIL-15) in cancer patients. We have completed a first-in-human (FIH), phase I dose escalation trial of E. coli produced rhIL-15 administered as a 30 minute intravenous bolus (IVB) infusion given daily for 12 consecutive days to patients with metastatic melanoma (MM) or renal cell carcinoma (mRCC). rhIL-15 treatment produced up to an 8-fold expansion of circulating NK cells, approximately 2 fold expansion of CD8+ CD45RO+ memory T-cells and up to 50 fold increases in serum level for multiple cytokines. Characteristic toxicities associated with cytokine treatment such as fever, rigors or chills, capillary leak, myalgias and blood pressure changes occurred at frequency and severity proportional to the dose of rhIL-15. Laboratory results showed early course transient leukopenia, lymphopenia, modest neutropenia, occasional thrombocytopenia and significant elevations of alanine and asparagine transaminase (ALT, AST) in a number of patients. Antibodies to rhIL-15 antibodies were not detected in any patient. The maximum tolerated dose for this schedule was 0.3 μg/kg/day with dose-limiting toxicities (DLTs) of grade 3 hypotension, thrombocytopenia, grade 3 or 4 ALT and AST elevation. There were no documented objective responses by RECIST criteria, but decreases in the sum of diameters for the marker lesions between 10 and 30% and improvement or clearance of parenchymal lung metastases were observed in several patients suggesting some antitumor activity.

A phase I dose escalation trial evaluating a 10 day (240 hour) continuous intravenous infusion (CIV) of rhIL-15 which is expected to produce greater expansion of CD8 effector cells and immune activation has been initiated. Patients treated at the first two dose levels have demonstrated improved clinical tolerability, immune activation; fewer laboratory abnormalities and no DLTs. Patient accrual and dose escalation to the third dose level are ongoing.

Citation Format: Kevin C. Conlon, Enrico Lugli, Steven A. Rosenberg, John C. Morris, Thomas Fleisher, Hugh Welles, Sigrid Dubois, Liyanage Perera, Carolyn Goldman, Bonita Bryant, Jean Decker, Joanna Shih, Tat'Yana Worthy, William Figg, Cody Peer, Michael Sneller, H. Clifford Lane, Jason Yovandich, Stephen Creekmore, Mario Roederer, Thomas A. Waldmann. Results from the first-in-human phase I trials of recombinant human Interleukin 15 (rhIL-15) administered as a daily 30 minute intravenous infusion (IVB) for 12 consecutive days or as continuous intravenous infusion (CIV) for 240 hours in patients with refractory metastatic cancers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2575. doi:10.1158/1538-7445.AM2014-2575

Polymorphisms in ALOX12, but not ALOX15, are significantly associated with BMD in postmenopausal women

The murine arachidonate 15-lipoxygenase gene (Alox15) has recently been identified as a negative regulator of peak bone mineral density (BMD). The human ALOX15 gene shares significant sequence homology with the murine Alox15 gene; however, the human arachidonate 12-lipoxygenase gene (ALOX12) is functionally more similar to the mouse gene. Multiple single-nucleotide polymorphisms (SNPs) in the human ALOX15 and ALOX12 genes have previously been reported to be significantly associated with BMD in humans. On the basis of these data, we carried out our own investigation of the human ALOX15 and ALOX12 genes and their relationship with hip and spine BMD parameters. The study population consisted of 779 postmenopausal women with a mean (+/- standard deviation) age of 62.5 +/- 5.9 years at BMD measurement and was recruited from a single large general practice in Chingford, northeast London. Three SNPs from ALOX15 and five from ALOX12 were analyzed. None of the SNPs that we analyzed in ALOX15 were significantly associated with any of the BMD parameters or fracture data. However, we found that three SNPs from ALOX12, all previously associated with spine BMD in women, were significantly associated with spine and various hip BMD parameters in our cohort (P = 0.029-0.049). In conclusion, we found no association between polymorphism in ALOX15 and BMD phenotypes but were able to replicate previous findings that genetic variation in ALOX12 seems to play a role in determining bone structure in Caucasian women.