Hepatobiliary-specific contrast agents are one of several classes of contrast agents available for magnetic resonance (MR) imaging of the liver. These agents are taken up by functioning hepatocytes and excreted in the bile, and their paramagnetic properties cause shortening of the longitudinal relaxation time (T1) of the liver and biliary tree. The three contrast agents that have been developed are mangafodipir trisodium (Mn-DPDP), gadobenate dimeglumine (Gd-BOPTA), and gadoxetic acid (Gd-EOB-DTPA). These three MR contrast agents vary in mode of administration and dose, mechanism of cellular uptake, degree of excretion through the biliary pathway, and imaging characteristics. In the liver, hepatobiliary-specific agents can be used to improve lesion detection, to characterize lesions as hepatocellular or nonhepatocellular, and to specifically characterize some hepatocellular lesions, notably focal nodular hyperplasia. Biliary excretion of these agents can be used to evaluate the anatomic structure and function of the biliary tree. In the future, hepatobiliary-specific contrast agents may have wider applications, such as grading of cirrhosis and quantification of liver function.

https://pubs.rsna.org/doi/pdf/10.1148/rg.296095515

Hepatobiliary-specific MR Contrast Agents: Role in Imaging the Liver and Biliary Tree

https://aasldpubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lt.23729

Three‐dimensional print of a liver for preoperative planning in living donor liver transplantation

Objectives:The aim of this prospective study was to evaluate the diagnostic performance of magnetic resonance imaging (MRI) of the liver with the hepatocellular-specific contrast agent gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) in comparison to precontrast MRI and spir

Diagnostic performance and description of morphological features of focal nodular hyperplasia in Gd-EOB-DTPA-enhanced liver magnetic resonance imaging: results of a multicenter trial.

Visualization in Medicine is the first book on visualization and its application to problems in medical diagnosis, education, and treatment. The book describes the algorithms, the applications and their validation (how reliable are the results?), and the clinical evaluation of the applications (are the techniques useful?). It discusses visualization techniques from research literature as well as the compromises required to solve practical clinical problems. 

The book covers image acquisition, image analysis, and interaction techniques designed to explore and analyze the data. The final chapter shows how visualization is used for planning liver surgery, one of the most demanding surgical disciplines. The book is based on several years of the authors' teaching and research experience. Both authors have initiated and lead a variety of interdisciplinary projects involving computer scientists and medical doctors, primarily radiologists and surgeons.

* A core field of visualization and graphics missing a dedicated book until now
* Written by pioneers in the field and illustrated in full color
* Covers theory as well as practice

Visualization in Medicine: Theory, Algorithms, and Applications

A method and system of compensation for intra-operative organ shift of a living subject usable in image guide surgery. In one embodiment, the method includes the steps of generating a first geometric surface of the organ of the living subject from intra- operatively acquired images of the organ of the living subject, constructing an atlas of organ deformations of the living subject from pre-operatively acquired organ images from the pre-operatively acquired organ images, generating a second geometric surface of the organ from the atlas of organ deformations, aligning the second geometric surface of the organ to the first geometric surface of the organ of the living subject to determine at least one difference between a point of the first geometric surface and a corresponding point of the second geometric surface of the organ of the living subject, which is related to organ shift, and compensating for the intra-operative organ shift.

Apparatus and methods of compensating for organ deformation, registration of internal structures to images, and applications of same

The aim of this study was to evaluate a software tool for non-invasive preoperative volumetric assessment of potential donors in living donated liver transplantation (LDLT). Biphasic helical CT was performed in 56 potential donors. Data sets were post-processed using a non-commercial software tool for segmentation, volumetric analysis and visualisation of liver segments. Semi-automatic definition of liver margins allowed the segmentation of parenchyma. Hepatic vessels were delineated using a region-growing algorithm with automatically determined thresholds. Volumes and shapes of liver segments were calculated automatically based on individual portal-venous branches. Results were visualised three-dimensionally and statistically compared with conventional volumetry and the intraoperative findings in 27 transplanted cases. Image processing was easy to perform within 23 min. Of the 56 potential donors, 27 were excluded from LDLT because of inappropriate liver parenchyma or vascular architecture. Two recipients were not transplanted due to poor clinical conditions. In the 27 transplanted cases, preoperatively visualised vessels were confirmed, and only one undetected accessory hepatic vein was revealed. Calculated graft volumes were 1110 +/- 180 ml for right lobes, 820 ml for the left lobe and 270 +/- 30 ml for segments II+III. The calculated volumes and intraoperatively measured graft volumes correlated significantly. No significant differences between the presented automatic volumetry and the conventional volumetry were observed. A novel image processing technique was evaluated which allows a semi-automatic volume calculation and 3D visualisation of the different liver segments.

3D CT modeling of hepatic vessel architecture and volume calculation in living donated liver transplantation.

The purpose of this study was to develop a software tool for the insertion of virtual lung nodules into CT data. Forty software-generated nodules were inserted at random locations and sizes on 20 multi-detector row CT studies of the chest (4×1-2.5-mm slice collimation). On each scan, two virtual nodules were inserted. The size, shape, margin and attenuation could arbitrarily vary and were individually adjusted to match real lesions of each patient (real nodules: 6.5±3.1 mm; virtual nodules: 6.1±3.2 mm). Additionally, noise and a random pattern simulating local density variations were added to virtual nodules. Three blinded readers evaluated 40 real and 40 simulated nodules according to a 5-point confidence scale ranging from 1 (definitely simulated) to 5 (definitely real). A multivariate analysis of covariance was performed for statistical assessment (SPSS 11.5, Chicago, IL). Real and simulated lesions were indistinguishable for all three readers (Pillai’s trace statistic: P=0.881). However, nodule size was a statistically significant covariable regarding the differentiation of virtual compared to real nodules. Larger simulated nodules were easier to detect than smaller ones (Pillai’s trace statistic: P<0.05). The developed algorithm allowed for the synthetic generation of lung nodules that were indistinguishable from real nodules.

Insertion of virtual pulmonary nodules in CT data of the chest: development of a software tool.

Rationale and Objectives: Sequential contrast changes of mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance imaging (MRI) were evaluated in the differentiation of focal nodular hyperplasias (FNH) and hepatocellular carcinomas (HCC). Methods: Patients with FNH (n = 16) or HCC (n = 12) underwent MRI: T 2 -weighted fast spin echo before and T 1 -weighted gradient echo before and 1, 4, 14, and 22 hours after 5 μmol/kg Mn-DPDP. Homogeneity of enhancement and delineation of fibrous scars of FNHs were assessed qualitatively. Lesion-to-liver contrast changes of FNHs and HCCs were compared quantitatively (Mann-Whitney U). Results: Mn-DPDP improved detection of characteristic scars of FNHs from 50% before to 90% after contrast agent. Apart from fibrous tissue enhancement of FNHs was mostly homogeneous (90%). Time-dependent contrast changes were up to 20 times higher (after 4 hours) for FNHs than HCCs (P < 0.0001). Conclusions: Mn-DPDP-enhanced MRI helps to delineate characteristic morphologic features of FNHs and can provide quantitative data differentiating FNH and HCC.

Dagmar Högemann Savellano

Papers

3D CT modeling of hepatic vessel architecture and volume calculation in living donated liver transplantation.

Insertion of virtual pulmonary nodules in CT data of the chest: development of a software tool.

Assessment of sequential enhancement patterns of focal nodular hyperplasia and hepatocellular carcinoma on mangafodipir trisodium enhanced MR imaging.