Liver CT Research Articles

Accuracy of preoperative liver volumetry in living donor liver transplantation—A systematic review and meta-analysis

BackgroundLiver volume measurement plays a critical role in the clinical success of living donor liver transplantation (LDLT). CT liver volumetry is used for volumetric assessment of the donor hepatectomy. However, the degree of accuracy of the preoperative predicted volumetric measurements remains unclear. PurposeThis systematic review will assess the accuracy of CT liver volumetry. Materials and MethodsA systematic literature search was conducted to evaluate the accuracy of the CT based liver volumetry. To assess the difference between the left and right liver lobe the ratio between preoperative estimated graft volume (EGV) and actual graft weight (AGW) was calculated. A meta-analysis was performed to compare the EGV to the AGW of the left and right lobe with automated and manual CT volume prediction. ResultsThirty-one studies met the inclusion criteria and 1336 patients were included in the meta-analysis. The EGV of the right liver is overestimated with a mean of 4.01% and 2.99% for automated and manual volumetry respectively. The left lobe is overestimated with 6.28% and 14.41% for automated and manual volumetry respectively. For a right lobe liver graft automated volume prediction showed a mean difference of 43.9 g (95% confidence interval (CI): 21.21–66.54, p<0.001) between EGV and AGW. For manual volume prediction this was 34.0 g (95% CI: 11.85–56.11, p = 0.003). For a left lobe with automated volume prediction the mean difference was 46.0 g (95% CI: 20.91–71.09, p<0.001) between EGV and AGW. For manual volume prediction this was 39.6 g (95% CI: 8.40–70.74, p = 0.01). ConclusionThe volumes of the right and left liver lobe seem to be overestimated with automated and manual CT volume prediction. Considering the larger estimation error in the prediction of the left liver lobe, special attention should be paid to the volume when performing a LDLT with a left liver lobe to prevent small for size syndrome.

GANs for Medical Image Synthesis: An Empirical Study.

Generative adversarial networks (GANs) have become increasingly powerful, generating mind-blowing photorealistic images that mimic the content of datasets they have been trained to replicate. One recurrent theme in medical imaging, is whether GANs can also be as effective at generating workable medical data, as they are for generating realistic RGB images. In this paper, we perform a multi-GAN and multi-application study, to gauge the benefits of GANs in medical imaging. We tested various GAN architectures, from basic DCGAN to more sophisticated style-based GANs, on three medical imaging modalities and organs, namely: cardiac cine-MRI, liver CT, and RGB retina images. GANs were trained on well-known and widely utilized datasets, from which their FID scores were computed, to measure the visual acuity of their generated images. We further tested their usefulness by measuring the segmentation accuracy of a U-Net trained on these generated images and the original data. The results reveal that GANs are far from being equal, as some are ill-suited for medical imaging applications, while others performed much better. The top-performing GANs are capable of generating realistic-looking medical images by FID standards, that can fool trained experts in a visual Turing test and comply to some metrics. However, segmentation results suggest that no GAN is capable of reproducing the full richness of medical datasets.

"ASSESSING THE EFFECTIVENESS OF OPTIMIZED CONTRAST AGENT USAGE IN CT SCANNING"

Background: To assess individually optimized protocol of contrast medium injection in enhanced CT scan for liver imaging.Materials &amp; methods: 50 patients who underwent liver CT scan were included in the present study.Random division of all the patients was done into two study groups as follows:Group A and group B (25 patients in each group).All the patients were scanned using CT machine.All patients underwent both unenhanced and enhanced CT scans during hepatic arterial phase (HAP) and portal venous phase (PVP).All the enhanced CT scans during HAP and PVP started at thirty-five seconds and sixty-five seconds respectively, after the contrast injection, from the level of diaphragm to inferior hepatic edge. Both groups received the same contrast medium. Group A adopted an individually optimized protocol of the platform, which automatically calculated the contrast medium dose. Patients of group B received a standard contrast medium injection protocol with a contrast medium to weight dose of 1.5 ml/kg. CT values of unenhanced liver parenchyma, CT values of liver parenchyma during HAP and PVP, and CT values of the portal vein during PVP were measured.CT examinations were performed in both group A and group B patients.Analysis of results was done using SPSS software.Results: Mean CT value of liver parenchyma during HAP (HU) among patients of group A and group B was 78.3 and 77.1 respectively. Mean CT value of liver parenchyma during PVP (HU) among patients of group A and group B was 103.1 and 108.3 respectively.Mean CT value of portal vein during PVP (HU) among patients of group A and group B was 145.3 and 158.7 respectively.Mean Contrast medium dose (ml) among patients of group A and group B was 79.2 and 95.3 respectively.Significant results were obtained while comparing the outcome variables among the two study groups. Conclusion: From the above results, the authors concluded that in enhanced CT scan for liver imaging,individualizing the contrast dose on the basis of body weight through contrast medium injection protocol could efficaciously decrease contrast medium dose

On Selecting, Ranking, and Quantifying Features for Building a Liver CT Diagnosis Aiding Computational Intelligence Method

The liver is one of the most common locations for incidental findings during abdominal CT scans. There are multiple types of disease that can arise within the liver and many of them are nodular. The ultimate goal of our research is to develop an expert knowledge-based system using fuzzy signatures, to support decisions during diagnosis of the most frequent of these nodular lesions. Since the literature contains limited information about the graphical properties of CT images that must be taken into consideration and their relationship to one another, in this paper we focused on selecting and ranking the input parameters using expert knowledge and determining their importance. Six visual attributes of lesions (size, shape, density, homogeneity contour, and other features) were selected based on textbooks of radiology and expert opinion. The importance of these attributes was ranked by radiologist experts using questionnaires and a pairwise comparison technique. The most important feature was found to be the density of the lesion on the various CT phases, and the least important was the size, the order of the other attributes was other features, contour, homogeneity, and shape, with a Kendall concordance coefficient of 0.612. Weights for the attributes, to be used in the future fuzzy signatures, were also determined. As a last step, several statistical parameter-based quantities were generated to represent the above abstract attributes and evaluated by comparing them to expert opinions.

Evaluation of liver metastasis in patients with breast cancer: Comparison of single-phase abdominopelvic CT and multi-phase liver CT.

To compare the usefulness of multi-phase liver CT and single-phase abdominopelvic CT (APCT) in evaluating liver metastasis in newly diagnosed breast cancer patients. In this retrospective study, a total of 7621 newly diagnosed breast cancer patients (mean age, 49.7years ± 10.1; 7598 women) who underwent single-phase APCT (n = 5536) or multi-phase liver CT (n = 2085) for staging workup between January 2016 and June 2019 were included. The staging CTs were categorized as having no metastasis, probable metastasis, or indeterminate lesions. MRI referral rate (proportion of patients underwent additional liver MRI), negative MRI rate (patients without true hepatic metastasis / patients underwent liver MRI), true positive CT rate (patients with true metastasis / patients categorized as probable metastasis), true metastasis rate among CT indeterminate (patients with true metastasis / patients categorized as indeterminate lesions), and overall liver metastasis rate were compared between the two groups. Further, the radiation dose was recorded for every patient. The proportions of having no metastasis and indeterminate lesions on the results of CT interpretation were significantly different between the two groups (P = 0.006). However, the MRI referral rate, negative MR rate, true positive CT rate, true metastasis rate among CT indeterminate, and overall liver metastasis rate were not significantly different between the two groups. Radiation dose of multi-phase CT was three times higher than that of single-phase CT. Multi-phase liver CT has little benefit over single-phase APCT in assessing liver metastasis in patients with breast cancer.

Quantitative Analysis of Liver Iron Deposition Based on Dual-Energy CT in Thalassemia Patients.

To explore the feasibility and accuracy of liver iron deposition based on dual-energy CT in thalassemia patients. 105 thalassemia patients were examined with dual-energy CT and MR liver scanning. Dual-energy CT was performed to measure CT values on 80kVp, 140kVp, and virtual iron content (VIC) imaging; ΔH was figured out by the difference in CT values between 80kVp and 140kVp. Using the liver iron concentration (LIC) obtained by FerriScan as a gold standard, the correlation between CT measurements and LIC was evaluated. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance for dual-energy CT in liver iron quantification and stratification. The correlation analysis between CT measurements and LIC showed that 80kVp, 140kVp, VIC, and ΔH all had a high positive correlation with LIC (P<0.001). The correlation analysis among different degree groups of VIC, ΔH, and LIC showed that the normal, moderate, and severe groups of VIC and ΔH had moderate or high positive correlations with that of LIC (P<0.01), but the mild group had no correlation (P>0.05). ROC analysis revealed that the corresponding optimal cutoff value of VIC was -2.8, 6.3,11.9 HU (corresponds to 3.2,7.0,15.0 mg/g dry weight) respectively, while the ΔH were 5.1, 8.4, 17.8HU, respectively. The area under the receiver operating characteristic curves (AUCs) for both VIC and ΔH increased with LIC thresholds. Dual-energy CT can accurately quantify and stratify liver iron deposition, contributing to predicting the status of liver iron deposition in thalassemia patients.

Added Value of Pelvic CT after Treatment of HCC.

Background In patients with hepatocellular carcinoma (HCC) who undergo follow-up with CT after treatment, the benefit of routinely including pelvic coverage is not well substantiated. Purpose To investigate the added value of pelvic coverage at follow-up liver CT in detecting pelvic metastasis or incidental tumors in patients treated for HCC. Materials and Methods This retrospective study included patients who were diagnosed with HCC between January 2016 and December 2017 and followed up with liver CT after treatment. Cumulative rates of extrahepatic metastasis, isolated pelvic metastasis, and incidental pelvic tumor were estimated by using the Kaplan-Meier method. Cox proportional hazard models were used to identify risk factors for extrahepatic and isolated pelvic metastases. Radiation dose from pelvic coverage was also calculated. Results A total of 1122 patients (mean age, 60 years ± 10 [SD]; 896 men) were included. The cumulative rates at 3 years of extrahepatic metastasis, isolated pelvic metastasis, and incidental pelvic tumor were 14.4%, 1.4%, and 0.5%, respectively. At adjusted analysis, protein induced by vitamin K absence or antagonist-II (P = .001), size of the largest tumor (P = .02), T stage (P = .008), and initial treatment method (P < .001) were associated with extrahepatic metastasis. Only T stage was associated with isolated pelvic metastasis (P = .01). Because of pelvic coverage, the radiation dose increased by 29% and 39% in liver CT with and without contrast enhancement, respectively, compared with CT scans without pelvic coverage. Conclusion The incidence of isolated pelvic metastasis or incidental pelvic tumor was low in patients treated for hepatocellular carcinoma. © RSNA, 2023.

Obesity-Associated Hepatic Steatosis, Somatotropic Axis Impairment, and Ferritin Levels Are Strong Predictors of COVID-19 Severity.

The full spectrum of SARS-CoV-2-infected patients has not yet been defined. This study aimed to evaluate which parameters derived from CT, inflammatory, and hormonal markers could explain the clinical variability of COVID-19. We performed a retrospective study including SARS-CoV-2-infected patients hospitalized from March 2020 to May 2021 at the Umberto I Polyclinic of Rome. Patients were divided into four groups according to the degree of respiratory failure. Routine laboratory examinations, BMI, liver steatosis indices, liver CT attenuation, ferritin, and IGF-1 serum levels were assessed and correlated with severity. Analysis of variance between groups showed that patients with worse prognoses had higher BMI and ferritin levels, but lower liver density, albumin, GH, and IGF-1. ROC analysis confirmed the prognostic accuracy of IGF-1 in discriminating between patients who experienced death/severe respiratory failure and those who did not (AUC 0.688, CI: 0.587 to 0.789, p < 0.001). A multivariate analysis considering the degrees of severity of the disease as the dependent variable and ferritin, liver density, and the standard deviation score of IGF-1 as regressors showed that all three parameters were significant predictors. Ferritin, IGF-1, and liver steatosis account for the increased risk of poor prognosis in COVID-19 patients with obesity.

High-resolution MR imaging with gadoxetate disodium for the comprehensive evaluation of potential living liver donors.

Several major transplantation centers have used composite multimodality evaluation for the preoperative evaluation of potential living liver donors. This approach can be time-consuming and, although rare, can cause complications. We aimed to demonstrate the clinical feasibility of our comprehensive preoperative MR protocol for the preoperative assessment of living liver donor candidates instead of composite multimodality evaluation. Thirty-five consecutive living liver donor candidates underwent multiphasic liver CT and comprehensive donor protocol MR examinations for preoperative evaluation in a single large-volume liver transplantation (LT) center. Three blinded abdominal radiologists reviewed the CT and MR images for vascular and biliary variations. The strength of agreement between CT and MR angiography was assessed using the kappa index. The detection rate of biliary anatomical variations was calculated. The sensitivity and specificity for detecting significant steatosis (>5%) were calculated. The estimated total volume and right lobe volumes measured by MR volumetry were compared with the corresponding CT volumetry measurements using the intraclass correlation coefficient (ICC). Among the 35 patients, 26 underwent LT. The measurement of agreement showed a moderate to substantial agreement between CT and MR angiography interpretations (kappa values, 0.47-0.79; p < 0.001). Combining T2-weighted and T1-weighted MR cholangiography techniques detected all biliary anatomical variations in 9 of the 26 patients. MR-proton density fat fraction showed a sensitivity of 100% (3/3) and a specificity of 91.3% (21/23) for detecting pathologically determined steatosis (>5%). MR volumetry reached an excellent agreement with CT volumetry (reviewers 1 and 2: ICC, 0.92; 95% CI, 0.84-0.96). Our one-stop comprehensive liver donor MR imaging protocol can provide complete information regarding hepatic vascular and biliary anatomies, hepatic parenchymal quality, and liver volume for living liver donor candidates and can replace composite multimodality evaluation.

A rare case of neonatal-onset hepatic sinusoidal obstruction syndrome

A male infant, aged 1 month and 14 days, was admitted to the hospital due to abdominal distension lasting for 2 weeks and worsening for 3 days. The infant had a history of omphalitis. Physical examination revealed severe abdominal distension, prominent abdominal wall veins, hepatosplenomegaly, and massive ascites. There was a slight elevation in liver transaminase levels. Liver ultrasound and CT scans demonstrated the absence of visualization of the intrahepatic segment of the portal vein and the left, middle, and right veins of the liver, indicating occlusion of these vessels, along with surrounding fibrous hyperplasia. The clinical diagnosis was hepatic sinusoidal obstruction syndrome resulting from omphalitis. A large amount of bloody ascites developed after 12 days of hospitalization, resulting in hypovolemic shock and respiratory failure. The infant passed away following the family's decision to discontinue treatment. This article focuses on the diagnostic approach and multidisciplinary management of neonatal-onset hepatic sinusoidal obstruction syndrome, as well as provides insights into the differential diagnosis of hepatomegaly and ascites.

Attention Mechanism Trained with Small Datasets for Biomedical Image Segmentation

The understanding of long-range pixel–pixel dependencies plays a vital role in image segmentation. The use of a CNN plus an attention mechanism still has room for improvement, since existing transformer-based architectures require many thousands of annotated training samples to model long-range spatial dependencies. This paper presents a smooth attention branch (SAB), a novel architecture that simplifies the understanding of long-range pixel–pixel dependencies for biomedical image segmentation in small datasets. The SAB is essentially a modified attention operation that implements a subnetwork via reshaped feature maps instead of directly calculating a softmax value over the attention score for each input. The SAB fuses multilayer attentive feature maps to learn visual attention in multilevel features. We also introduce position blurring and inner cropping specifically for small-scale datasets to prevent overfitting. Furthermore, we redesign the skip pathway for the reduction of the semantic gap between every captured feature of the contracting and expansive path. We evaluate the architecture of U-Net with the SAB (SAB-Net) by comparing it with the original U-Net and widely used transformer-based models across multiple biomedical image segmentation tasks related to the Brain MRI, Heart MRI, Liver CT, Spleen CT, and Colonoscopy datasets. Our training set was made of random 100 images of the original training set, since our goal was to adopt attention mechanisms for biomedical image segmentation tasks with small-scale labeled data. An ablation study conducted on the brain MRI test set demonstrated that every proposed method achieved an improvement in biomedical image segmentation. Integrating the proposed methods helped the resulting models consistently achieve outstanding performance on the above five biomedical segmentation tasks. In particular, the proposed method with U-Net improved its segmentation performance over that of the original U-Net by 13.76% on the Brain MRI dataset. We proposed several novel methods to address the need for modeling long-range pixel–pixel dependencies in small-scale biomedical image segmentation. The experimental results illustrated that each method could improve the medical image segmentation accuracy to various degrees. Moreover, SAB-Net, which integrated all proposed methods, consistently achieved outstanding performance on the five biomedical segmentation tasks.

Prospective Multicentric Assessment of 68Ga-DOTANOC PET/CT in Grade 1-2 GEP-NET.

The aim of this multicentric study was to prospectively compare 68Ga-DOTANOC PET/CT versus somatostatin receptor scintigraphy (SRS) with SPECT/CT, combined with multiphasic CT scan and MRI in patients with grade 1 or 2 gastroenteropancreatic neuroendocrine tumors (GEP-NET). Patients with histologically proven grade 1 or 2 GEP-NET with suspicion of recurrence or progression, or with typical aspects of GEP-NET on morphological imaging, were explored with conventional imaging (CI): SRS with SPECT/CT, multiphasic CT scan and/or liver MRI followed by 68Ga-DOTANOC PET/CT. The gold standard was based on histology and imaging follow-up. The data of 105 patients (45 woman and 60 men; median age) were analyzed. 68Ga-DOTANOC PET/CT sensitivity was significantly higher than CI sensitivity in per-patient (98.9% vs. 88.6%, p = 0.016) and per-region (97.6% vs. 75.6%, p &lt; 0.001) analyses, in the detection of the primary (97.9% vs. 78.7%; p = 0.016), peritoneal carcinomatosis (95% vs. 30%, p &lt; 0.001), and bone metastases (100% vs. 33.3%, p = 0.041). 68Ga-DOTANOC PET/CT had an impact on the therapeutic management of 41.9% (44/105) patients compared to decisions based on CI explorations. Our data confirm the superiority of 68Ga-DOTANOC PET/CT over CI in the detection of peritoneal carcinomatosis and bone metastasis, as well as its strong therapeutic impact on the management of patients with grade 1-2 GEP-NETs.

Hepatocellular Carcinoma with Bile Duct Tumor Thrombus: A Case Report and Literature Review of 890 Patients Affected by Uncommon Primary Liver Tumor Presentation.

Bile duct tumor thrombus (BDTT) is an uncommon finding in hepatocellular carcinoma (HCC), potentially mimicking cholangiocarcinoma (CCA). Recent studies have suggested that HCC with BDTT could represent a prognostic factor. We report the case of a 47-year-old male patient admitted to the University Hospital of Bari with abdominal pain. Blood tests revealed the presence of an untreated hepatitis B virus infection (HBV), with normal liver function and without jaundice. Abdominal ultrasonography revealed a cirrhotic liver with a segmental dilatation of the third bile duct segment, confirmed by a CT scan and liver MRI, which also identified a heterologous mass. No other focal hepatic lesions were identified. A percutaneous ultrasound-guided needle biopsy was then performed, detecting a moderately differentiated HCC. Finally, the patient underwent a third hepatic segmentectomy, and the histopathological analysis confirmed the endobiliary localization of HCC. Subsequently, the patient experienced a nodular recurrence in the fourth hepatic segment, which was treated with ultrasound-guided percutaneous radiofrequency ablation (RFA). This case shows that HCC with BDTT can mimic different types of tumors. It also indicates the value of an early multidisciplinary patient assessment to obtain an accurate diagnosis of HCC with BDTT, which may have prognostic value that has not been recognized until now.

Evaluation of Focal Hepatic Lesion and associated changes in Gallbladder and Kidneys using Spiral Computed Tomography

Focal hepatic lesions are the lesions in the liver apart from its usual parenchyma. Objective: To check the efficiency of triphasic computed tomography for diagnosing benign and malignant focal liver lesions and to assess frequencies of both types of liver lesions. Methods: On 60 patients, triphasic CT scan for the liver was performed in Allied Hospital, Faisalabad. The liver was scanned in the arterial, the portal-venous, and the delayed phases followed by contrast injection. During all of these phases evaluation of lesions was made on enhancement patterns and frequencies of each lesion was checked. Results: The results showed that out of 60 patients 26(43.3%) were diagnosed with benign and 34(56.67%) were diagnosed with malignant focal liver lesions. Benign cases had a higher frequency of Haemangioma and malignant cases had a higher frequency of hepatocellular carcinoma. The overall study showed the percentage of incidents in gallbladder and renal system. Conclusions: The triphasic CT liver due to its accuracy provides assured diagnosis for liver lesions and thus reduces biopsy procedures

Predictors of need for endovascular intervention in hepatic trauma.

Non-operative management of hepatic trauma with adjunctive hepatic arterial embolization (HAE) is widely accepted. Despite careful patient selection utilizing CTA, a substantial proportion of angiograms are negative for arterial injury and no HAE is performed. This study aims to determine which CT imaging findings and clinical factors are associated with the presence of active extravasation on subsequent angiography in patients with hepatic trauma. The charts of 243 adults who presented with abdominal trauma and underwent abdominal CTA followed by conventional angiography were retrospectively reviewed. Of these patients, 49 had hepatic injuries on CTA. Hepatic injuries were graded using the American association for the surgery of trauma (AAST) CT classification, and CT images were assessed for active contrast extravasation, arterial pseudoaneurysm, sentinel clot, hemoperitoneum, laceration in-volving more than 2 segments, and laceration involving specific anatomic landmarks (porta hepatis, hepatic veins, and gallbladder fossa). Medical records were reviewed for pre- and post-angiography blood pressures, hemoglobin levels, and transfusion requirements. Angiographic images and reports were reviewed for hepatic arterial injury and performance of HAE. In multivariate analysis, AAST hepatic injury grade was significantly associated with increased odds of HAE (Odds ratio: 2.5, 95% CI 1.1, 7.1, p = 0.049). Univariate analyses demonstrated no significant association between CT liver injury grade, CT characteristics of liver injury, or pre-angiographic clinical data with need for HAE. In patients with hepatic trauma, prediction of need for HAE based on CT findings alone is challenging; such patients require consideration of both clinical factors and imaging findings.

The Role of Computed Tomography Perfusion in Various Focal Liver Lesions.

Background This study aims to identify the potential advantages of quantitative determination of various focal liver pathologies, identify lesion hemodynamics, and distinguish benign and malignant pathologies based on CT perfusion (CTP) parameters. Methodology In this study, we examined 36 patients using contrast-enhanced CT (CECT) and proposed inclusion and exclusion criteria. Of the 36 patients, 18 had malignant lesions and 14 had benign lesions. CTP was performed on patients comprising cases of hepatocellular carcinoma (HCC), metastasis, hemangiomas, hepatic cysts, and hepatic abscess. Images were post-processed and analyzed to calculate various perfusion parameters such as blood flow (BF), blood volume (BV), permeability surface (PS), mean transit time (MTT), the hepatic arterial fraction (HAF), and induced residue fraction time of onset (IRFTO). Parameters were compared between benign and malignant lesions, and descriptive analysis was performed for individual lesions. Results Data were analyzed with IBM SPSS Statistics (IBM Corp., Armonk, NY, USA). IRFTO showed the area of the curve (AOC) = 0.659, P-value = 0.040, sensitivity 66.7%, and specificity 64.3%. BV showed AOC = 0.659, P-value = 0.040, with a cutoff value of 1.26, sensitivity of 66.7%, and specificity of 64.3%. BF showed AOC = 0.786 andP-value = 0.006, with a cutoff value of 171.2, sensitivity of 83.3%, and specificity of 78.6%. MTT showed AOC = 0.778 andP-value = 0.008, with a cutoff value of 6.94, sensitivity of 77.8%, and specificity of 78.6%. Statistically significant changes were observed in the perfusion parameters in the BV, BF, MTT, and IRFTO. Conclusions The noninvasive CT liver perfusion technique makes it possible to compare the hemodynamic changes in healthy and sick liver tissues, identify focal liver lesions, and evaluate the effectiveness of tumor therapy.

The use of CT Liver Volumetry for surgeon liver resection operation planning in Singapore General Hospital (SGH)

The use of CT Liver Volumetry for surgeon liver resection operation planning in Singapore General Hospital (SGH)

Learning Deformable Image Registration From Optimization: Perspective, Modules, Bilevel Training and Beyond.

Conventional deformable registration methods aim at solving an optimization model carefully designed on image pairs and their computational costs are exceptionally high. In contrast, recent deep learning-based approaches can provide fast deformation estimation. These heuristic network architectures are fully data-driven and thus lack explicit geometric constraints which are indispensable to generate plausible deformations, e.g., topology-preserving. Moreover, these learning-based approaches typically pose hyper-parameter learning as a black-box problem and require considerable computational and human effort to perform many training runs. To tackle the aforementioned problems, we propose a new learning-based framework to optimize a diffeomorphic model via multi-scale propagation. Specifically, we introduce a generic optimization model to formulate diffeomorphic registration and develop a series of learnable architectures to obtain propagative updating in the coarse-to-fine feature space. Further, we propose a new bilevel self-tuned training strategy, allowing efficient search of task-specific hyper-parameters. This training strategy increases the flexibility to various types of data while reduces computational and human burdens. We conduct two groups of image registration experiments on 3D volume datasets including image-to-atlas registration on brain MRI data and image-to-image registration on liver CT data. Extensive results demonstrate the state-of-the-art performance of the proposed method with diffeomorphic guarantee and extreme efficiency. We also apply our framework to challenging multi-modal image registration, and investigate how our registration to support the down-streaming tasks for medical image analysis including multi-modal fusion and image segmentation.

A patient-informed approach to predict iodinated-contrast media enhancement in the liver

ObjectiveTo devise a patient-informed time series model that predicts liver contrast enhancement, by integrating clinical data and pharmacokinetics models, and to assess its feasibility to improve enhancement consistency in contrast-enhanced liver CT scans. MethodsThe study included 1577 Chest/Abdomen/Pelvis CT scans, with 70–30% training/validation-testing split. A Gaussian function was used to approximate the early arterial, late arterial, and the portal venous phases of the contrast perfusion curve of each patient using their respective bolus tracking and diagnostic scan data. Machine learning models were built to predict the Gaussian parameters of each patient using the patient attributes (weight, height, age, sex, BMI). Pearson’s coefficient, mean absolute error, and root mean squared error were used to assess the prediction accuracy. ResultsThe integration of the pharmacokinetics model with a two-layered neural network achieved the highest prediction accuracy on the test data (R2 = 0.61), significantly exceeding the performance of the pharmacokinetics model alone (R2 = 0.11). Applying the model demonstrated that adjusting the contrast administration directed by the model may reduce clinical enhancement inconsistency by up to 40 %. ConclusionsA new model using a Gaussian function and supervised machine learning can be used to build liver parenchyma contrast enhancement prediction model. The model can have utility in clinical settings to optimize and improve consistency in contrast-enhanced liver imaging.

The change in the liver volume after direct intrahepatic portocaval shunt in patients with Budd-Chiari syndrome with diffuse hepatic vein occlusion.

To evaluate the changes in the liver volume and function after direct intrahepatic portocaval shunt (DIPS) in patients with Budd-Chiari syndrome (BCS) with diffuse hepatic vein (HV) occlusion. The clinical data of 29 patients with BCS who underwent DIPS for intractable ascites caused by diffuse hepatic vein occlusion in the Affiliated Hospital of Xuzhou Medical University were analysed retrospectively; the patients included 8 males and 21 females, with an average age of 33.3 ± 6.3years. The patients underwent abdominal CT scanning and liver function examinations before DIPS, and 1week, 3months, 6months and 12months after DIPS. The changes of the liver volume and liver function before and after DIPS were compared. All 29 patients underwent DIPS successfully. 28 patients survived during the follow-up of 12-33months, with a median follow-up of 16months. The patients' liver function were significantly improved at 3, 6 and 12months after the operation compared to before the operation (P < 0.05). The liver volumes measured before the operation and 1week, 3months, 6months and 12months after the operation were 2124.586 ± 420.889 cm3, 1926.263 ± 372.268 cm3, 1480.592 ± 183.061 cm3, 1461.904 ± 153.027 cm3 and 1469.286 ± 148.549 cm3, respectively. Compared with the preoperative liver volume, the liver volume had decreased significantly at 1week, 3months, 6months and 12months after the operation (P < 0.05). However, there was no significant difference in the liver volumes at 6 and 12months after the operation (P = 0.35). Direct intrahepatic portocaval shunt has achieved satisfactory clinical results in the treatment of BCS with diffuse hepatic vein occlusion. The congestive hepatomegaly was gradually reduced after the operation. The liver volume (which was defined as the clinical efficacy in this study) remained stable after 6months.