Dragon 1 Protocol Manuscript: Training, Accreditation, Implementation and Safety Evaluation of Portal and Hepatic Vein Embolization (PVE/HVE) to Accelerate Future Liver Remnant (FLR) Hypertrophy.

STUDY PURPOSE: The DRAGON 1 trial aims to assess training, implementation, safety and feasibility of combined portal- and hepatic-vein embolization (PVE/HVE) to accelerate future liver remnant (FLR) hypertrophy in patients with borderline resectable colorectal cancer liver metastases. METHODS: The DRAGON 1 trial is a worldwide multicenter prospective single arm trial. The primary endpoint is a composite of the safety of PVE/HVE, 90-day mortality, and one year accrual monitoring of each participating center. Secondary endpoints include: feasibility of resection, the used PVE and HVE techniques, FLR-hypertrophy, liver function (subset of centers), overall survival, and disease-free survival. All complications after the PVE/HVE procedure are documented. Liver volumes will be measured at week 1 and if applicable at week 3 and 6 after PVE/HVE and follow-up visits will be held at 1, 3, 6, and 12 months after the resection. RESULTS: Not applicable. CONCLUSION: DRAGON 1 is a prospective trial to assess the safety and feasibility of PVE/HVE. Participating study centers will be trained, and procedures standardized using Work Instructions (WI) to prepare for the DRAGON 2 randomized controlled trial. Outcomes should reveal the accrual potential of centers, safety profile of combined PVE/HVE and the effect of FLR-hypertrophy induction by PVE/HVE in patients with CRLM and a small FLR. TRIAL REGISTRATION: Clinicaltrials.gov: NCT04272931 (February 17, 2020). Toestingonline.nl: NL71535.068.19 (September 20, 2019).

Computed radiography versus mobile direct radiography for bedside chest radiographs: impact of dose on image quality and reader agreement.

AIM: To asses the image quality and potential for dose reduction of mobile direct detector (DR) chest radiography as compared with computed radiography (CR) for intensive care unit (ICU) chest radiographs (CXR). METHODS AND MATERIALS: Three groups of age-, weight- and disease-matched ICU patients (n=114 patients; 50 CXR per acquisition technique) underwent clinically indicated bedside CXR obtained with either CR (single read-out powder plates) or mobile DR (GOS-TFT detectors) at identical or 50% reduced dose (DR(50%)). Delineation of anatomic structures and devices used for patient monitoring, overall image quality and disease were scored by four readers. In 12 patients pairs of follow-up CR and DR images were available, and in 15 patients pairs of CR and DR(50%) images were available. In these pairs the overall image quality was also compared side-by-side. RESULTS: Delineation of anatomy in the mediastinum was scored better with DR or DR(50%) than with CR. Devices used for patient monitoring were seen best with DR, with DR(50%) being superior to CR. In the side-by-side comparison, the overall image quality of DR and DR(50%) was rated better than CR in 96% (46/48) and 87% (52/60), respectively. Inter-observer agreement for the assessment of pathology was fair for CR and DR(50%) (κ = 0.33 and κ = 0.39, respectively) and moderate for DR (κ = 0.48). CONCLUSION: Mobile DR units offer better image quality than CR for bedside chest radiography and allow for 50% dose reduction. Inter-observer agreement increases with image quality and is superior with DR, while DR(50%) and CR are comparable.

Computer-aided detection (CAD) of lung nodules and small tumours on chest radiographs.

Detection of focal pulmonary lesions is limited by quantum and anatomic noise and highly influenced by variable perception capacity of the reader. Multiple studies have proven that lesions - missed at time of primary interpretation - were visible on the chest radiographs in retrospect. Computer-aided diagnosis (CAD) schemes do not alter the anatomic noise but aim at decreasing the intrinsic limitations and variations of human perception by alerting the reader to suspicious areas in a chest radiograph when used as a 'second reader'. Multiple studies have shown that the detection performance can be improved using CAD especially for less experienced readers at a variable amount of decreased specificity. There seem to be a substantial learning process for both, experienced and inexperienced readers, to be able to optimally differentiate between false positive and true positive lesions and to build up sufficient trust in the capabilities of these systems to be able to use them at their full advantage. Studies so far focussed on stand-alone performance of the CAD schemes to reveal the magnitude of potential impact or on retrospective evaluation of CAD as a second reader for selected study groups. Further research is needed to assess the performance of these systems in clinical routine and to determine the trade-off between performance increase in terms of increased sensitivity and decreased inter-reader variability and loss of specificity and secondary indicated follow-up examinations for further diagnostic workup.

DR and CR: Recent advances in technology.

After some initial reluctance, nowadays transition from conventional analogue-to-digital radiographic technique is realized in the vast majority of institutions. The eventual triumph of digital over conventional technique is related to its undoubted advantages with respect to image quality and improved image handling in the context of a picture archiving and communication system. CR represents the older system, which matured over decades and experienced some important recent improvements with respect to dose efficiency and work-flow efficiency that strengthened its position. It represents a very versatile, economically attractive system that is equally suited for integrated systems as well as for cassette-based imaging at the bedside. DR systems offer superb image quality and realistic options for dose reduction based on their high dose efficiency. While for a long time only integrated systems were on the market suited for a large patient throughput, also mobile DR systems became recently available. While for the next years, it is likely that DR and CR systems will coexist, the long term perspective of CR will depend on further innovations with respect to dose efficiency and signal-to-noise characteristics while for DR economical aspects and broader availability of mobile systems will play a role.