Understanding ADC variation by fat content effect using a dual-function MRI phantom.

BACKGROUND: A dual-function phantom designed to quantify the apparent diffusion coefficient (ADC) in different fat contents (FCs) and glass bead densities (GBDs) to simulate the human tissues has not been documented yet. We propose a dual-function phantom to quantify the FC and to measure the ADC at different FCs and different GBDs. METHODS: A fat-containing diffusion phantom comprised by 30 glass-bead-containing fat-water emulsions consisting of six different FCs (0, 10, 20, 30, 40, and 50%) multiplied by five different GBDs (0, 0.1, 0.25, 0.5, and 1.0 g/50 mL). The FC and ADC were measured by the "iterative decomposition of water and fat with echo asymmetry and least squares estimation-IQ," IDEAL-IQ, and single-shot echo-planar diffusion-weighted imaging, SS-EP-DWI, sequences, respectively. Linear regression analysis was used to evaluate the relationship among the fat fraction (FF) measured by IDEAL-IQ, GBD, and ADC. RESULTS: The ADC was significantly, negatively, and linearly associated with the FF (the linear slope ranged from -0.005 to -0.017, R2 = 0.925 to 0.986, all p < 0.001). The slope of the linear relationship between the ADC and the FF, however, varied among different GBDs (the higher the GBD, the lower the slope). ADCs among emulsions across different GBDs and FFs were overlapped. Emulsions with low GBDs plus high FFs shared a same lower ADC range with those with median or high GBDs plus median or lower FFs. CONCLUSIONS: A novel dual-function phantom simulating the human tissues allowed to quantify the influence of FC and GBD on ADC. RELEVANCE STATEMENT: The study developed an innovative dual-function MRI phantom to explore the impact of FC on ADC variation that can affect clinical results. The results revealed the superimposed effect on FF and GBD density on ADC measurements. KEY POINTS: • A dual-function phantom made of glass bead density (GBD) and fat fraction (FF) emulsion has been developed. • Apparent diffusion coefficient (ADC) values are determined by GBD and FF. • The dual-function phantom showed the mutual ADC addition between FF and GBD.

Spleen-preserving distal pancreatectomy from multi-port to reduced-port surgery approach.

BACKGROUND: Minimally invasive pancreatic surgery via the multi-port approach has become a primary surgical method for distal pancreatectomy (DP) due to its advantages of lower wound pain and superior cosmetic results. Some studies have applied reduced-port techniques for DP in an attempt to enhance cosmetic outcomes due to the minimally invasive effects. Numerous recent review studies have compared multi-port laparoscopic DP (LDP) and multi-port robotic DP (RDP); most of these studies concluded multi-port RDP is more beneficial than multi-port LDP for spleen preservation. However, there have been no comprehensive reviews of the value of reduced-port LDP and reduced-port RDP. AIM: To search for and review the studies on spleen preservation and the clinical outcomes of minimally invasive DP that compared reduced-port DP surgery with multi-port DP surgery. METHODS: The PubMed medical database was searched for articles published between 2013 and 2022. The search terms were implemented using the following Boolean search algorithm: ("distal pancreatectomy" OR "left pancreatectomy" OR "peripheral pancreatic resection") AND ("reduced-port" OR "single-site" OR "single-port" OR "dual-incision" OR "single-incision") AND ("spleen-preserving" OR "spleen preservation" OR "splenic preservation"). A literature review was conducted to identify studies that compared the perioperative outcomes of reduced-port LDP and reduced-port RDP. RESULTS: Fifteen articles published in the period from 2013 to 2022 were retrieved using three groups of search terms. Two studies were added after manually searching the related papers. Finally, 10 papers were selected after removing case reports (n = 3), non-English language papers (n = 1), technique papers (n = 1), reviews (n = 1), and animal studies (n = 1). The common items were defined as items reported in more than five papers, and data on these common items were extracted from all papers. The ten studies included a total of 337 patients (females/males: 231/106) who underwent DP. In total, 166 patients (females/males, 106/60) received multi-port LDP, 126 (females/males, 90/36) received reduced-port LDP, and 45 (females/males, 35/10) received reduced-port RDP. CONCLUSION: Reduced-port RDP leads to a lower intraoperative blood loss, a lower postoperative pancreatic fistula rate, and shorter hospital stay and follow-up duration, but has a lower spleen preservation rate.