The feasibility of medial segment graft in pediatric liver transplantation revisited by three-dimensional printing.

BACKGROUND: The medial segment as a mono-segmental graft was proposed to increase the donor pool for pediatric liver transplantation, but to date, there has been no published case. This study aims to revisit the feasibility of procuring the medial segment graft (MSG) by three-dimensional (3D) printing and ex vivo procedures performed on explanted diseased livers to overcome the gap between theory and clinical implementation. METHODS: From October 2004 to December 2016, we retrospectively analyzed preoperative computed tomography, magnetic resonance cholangiopancreatography, and intraoperative cholangiography images of our previous live liver donors and identified the indicated anatomy for the MSG, then materialized by 3D printing models to simulate the engraftment. Furthermore, we practiced the procurement procedures on selected explanted diseased livers. RESULTS: Among 291 analyzed livers, 96 livers (33%) met the arterial criteria for MSG, and two-thirds of them had ideal portal branches for reconstruction. The proposed right border of the MSG was the Cantlie's line, and the left edge was the right side of the umbilical fissure. The mean estimated volume of the MSG was 234 ± 54 ml. Besides, we suggest implanting the MSG as an auxiliary partial graft in an inverted vertical position or a standalone graft with right-side rotation in the right subphrenic space. CONCLUSION: The procurement of the MSG is feasible based on our results. However, due to the novelty of the procedure, we suggest that the first attempted case of MSG should be implanted as an auxiliary partial graft to maximize patient safety. LEVEL OF EVIDENCE: Type of study: Case series with no comparison groups EVIDENCE LEVEL: Level IV.

Postablation assessment of hepatocellular carcinoma using dual-energy CT: Comparison of half versus standard iodine contrast medium.

This retrospective study was aimed to evaluate the reduced iodine load on image quality and diagnostic performance in multiphasic hepatic CT using a novel monoenergetic reconstruction algorithm (nMERA) in assessment of local tumor progression after radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC). Ninety patients who underwent CT 1 month after RFA of HCC. Forty-five patients had multiphasic hepatic dual-energy CT with a half-reduced contrast medium (HRCM) of 277.5 mg I/kg. The nMERA (40-70-keV) images were reconstructed in each phase. Another 45 patients received a standard contrast medium (SCM) of 555 mg I/kg, and the images were reconstructed as a simulated 120-kVp images. Primary outcome was accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) in assessment of local tumor progression. Additional advanced assessments included the image noise, attenuation value, contrast-to-noise ratio (CNR), and subjective image quality between the groups. The accuracy, sensitivity and specificity of nMERA HRCM images were 95.7%, 100% and 93.9% for 40 keV, 95.7%, 85.7% and 100% for 50 keV, 83.0%, 42.8% and 100% for 60 keV, and 83.0%, 42.9% and 100% for 70 keV. The AUROC was 0.99, 0.99, 0.94, and 0.93 for 40-70 keV nMERA HRCM images, respectively. Compared with simulated 120-kVp SCM images, nMERA HRCM images demonstrated comparable noise at 70-keV (P < 0.05), and comparable CNR at 40- and 50-keV (P < 0.05). nMERA DECT enables the contrast medium to be reduced to up to 50% in multiphasic hepatic CT while preserving diagnostic accuracy.

Attenuation values of renal parenchyma in virtual noncontrast images acquired from multiphase renal dual-energy CT: Comparison with standard noncontrast CT.

OBJECTIVES: To compare the renal parenchyma attenuation of virtual noncontrast (VNC) images derived from multiphase renal dual-energy computed tomography (DECT) with standard noncontrast (SNC) images, and to determine the optimum phase for VNC images. MATERIALS AND METHODS: Twenty-nine men and 16 women (mean age, 61 ±â€¯13 years; range, 37-89 years) underwent dynamic renal DECT (100/Sn140 kVp) were included in this institutional review board-approved retrospective study. There were four phases of the scan, which included noncontrast, corticomedullary (CMP), nephrographic (NP), and excretory phases (EP). The VNC images was generated from CMP, NP and EP. CT numbers of SNC images and VNC images of each phases were measured in the renal cortex and medulla. Mean standard deviation of subcutaneous fat was measured as image noise on SNC and VNC images. Radiation dose was recorded and potential radiation dose reduction was estimated. Results were tested for statistical significance using the unpaired t-test and agreement using Bland-Altman plot analysis. RESULTS: The difference in mean attenuation between SNC and each phase of VNC images were ≤4 HU. The mean attenuation of renal cortex and medulla was 33.2 ±â€¯4.4 HU, and 34.2 ±â€¯4.8 HU in SNC, 33.6 ±â€¯7.6 HU and 31.1 ±â€¯8.3 HU in VNC of CMP, 34.8 ±â€¯8.6 HU and 35.6 ±â€¯8.5 HU in VNC of NP, 31.5 ±â€¯7.6 HU and 32.4 ±â€¯7.5 HU in VNC of EP. In VNC of CMP, the attenuation of the cortex was higher than the medulla (p < 0.05), and the attenuation of medulla was significant lower than that of SNC (p < 0.01). In VNC of NP, the attenuation of renal cortex was higher than SNC (p < 0.05). In VNC of EP, the attenuation of cortex and medulla were lower than SNC (p < 0.05), and inadequate iodine subtraction in collecting system was noted. Image noise was significantly greater in SNC (p < 0.001). Mean radiation dose reduction achievable by removing the SNC was 12.3% ±â€¯0.9%. CONCLUSIONS: VNC images from multiphase renal DECT were similar to SNC images. Using the nephrographic phase can gives more comparable VNC images to SNC images in renal parenchyma than other phases.

Imaging spectrum after pancreas transplantation with enteric drainage.

Since the introduction of pancreas transplantation more than 40 years ago, surgical techniques and immunosuppressive regiments have improved and both have contributed to increase the number and success rate of this procedure. However, graft survival corresponds to early diagnosis of organ-related complications. Thus, knowledge of the transplantation procedure and postoperative image anatomy are basic requirements for radiologists. In this article, we demonstrate the imaging spectrum of pancreas transplantation with enteric exocrine drainage.

Prospective comparison of unenhanced spiral computed tomography and intravenous urography in the evaluation of acute renal colic.

BACKGROUND: The purpose of this prospective study was to evaluate the feasibility of replacing intravenous urography (IVU) with unenhanced computed tomography (CT) as the first line diagnostic modality for acute renal colic in the emergency department. METHODS: In the 1-year study period, 82 patients who presented themselves to the emergency room with acute renal colic and who were suspected to have ureteral stones were included. They received both IVU and unenhanced CT on the same day. RESULTS: Sixty-six patients were proven to have ureteral stone. Four had other urologic pathology (acute pyelonephritis, angiomyolipoma with hemorrhage, ureteropelvic junction stenosis). The remaining 12 had no definite urologic problem. Among the 66 patients with ureteral stone, the sensitivity for detecting ureteral stone was 98.5% for unenhanced CT and 59.1% for IVU. Correct diagnosis could be obtained in most of the patients receiving unenhanced CT, while IVU could provide only limited information about the intra-abdominal pathology other than urologic system, and as many as 31.7% of the patients needed further imaging examination (sonography, CT, magnetic resonance imaging). In 5 patients, the relationship of the calcified spot and ureter were unclear on axial images. With curved multiplanar reformatted reconstruction, the diagnosis of ureter stone could be confidently made. No side effect (renal toxicity, allergic reaction) from intravenous administration of iodine-containing contrast medium should be taken into consideration in CT. Besides, the average examination time was 108 minutes for IVU, which was significantly more than the 30 minutes for CT, including the time for curved multiplanar reformatted reconstruction. CONCLUSION: We consider that unenhanced CT is more effective and efficient than IVU and should replace IVU as the first-line diagnostic tool for ureteral stone in the emergency department.