Automated Assessment of T2-Weighted MRI to Differentiate Malignant and Benign Primary Solid Liver Lesions in Noncirrhotic Livers Using Radiomics

Rationale and Objectives: Distinguishing malignant from benign liver lesions based on magnetic resonance imaging (MRI) is an important but often challenging task, especially in noncirrhotic livers. We developed and externally validated a radiomics model to quantitatively assess T2-weighted MRI to distinguish the most common malignant and benign primary solid liver lesions in noncirrhotic livers. Materials and Methods: Data sets were retrospectively collected from three tertiary referral centers (A, B, and C) between 2002 and 2018. Patients with malignant (hepatocellular carcinoma and intrahepatic cholangiocarcinoma) and benign (hepatocellular adenoma and focal nodular hyperplasia) lesions were included. A radiomics model based on T2-weighted MRI was developed in data set A using a combination of machine learning approaches. The model was internally evaluated on data set A through cross-validation, externally validated on data sets B and C, and compared to visual scoring of two experienced abdominal radiologists on data set C. Results: The overall data set included 486 patients (A: 187, B: 98, and C: 201). The radiomics model had a mean area under the curve (AUC) of 0.78 upon internal validation on data set A and a similar AUC in external validation (B: 0.74 and C: 0.76). In data set C, the two radiologists showed moderate agreement (Cohen's κ: 0.61) and achieved AUCs of 0.86 and 0.82. Conclusion: Our T2-weighted MRI radiomics model shows potential for distinguishing malignant from benign primary solid liver lesions. External validation indicated that the model is generalizable despite substantial MRI acquisition protocol differences. Pending further optimization and generalization, this model may aid radiologists in improving the diagnostic workup of patients with liver lesions.</p

Institutional experience in the treatment of colorectal liver metastases with stereotactic body radiation therapy

AimTo investigate whether the impact of dose escalation in our patient population represented an improvement in local control without increasing treatment related toxicity.Materials and methodsA cohort of consecutive patients with colorectal liver metastases treated with stereotactic body radiation therapy (SBRT) between December 2002 and December 2013 were eligible for this study. Inclusion criteria were a Karnofsky performance status ≥80% and, according to the multidisciplinary tumor board, ineligibility for surgery or radiofrequency ablation. Exclusion criteria were a lesion size >6[[ce:hsp sp="0.25"/]]cm, more than 3 metastases, and treatment delivered with other fractionation scheme than 3 times 12.5[[ce:hsp sp="0.25"/]]Gy or 16.75[[ce:hsp sp="0.25"/]]Gy prescribed at the 65–67% isodose. To analyze local control, CT or MRI scans were acquired during follow-up. Toxicity was scored using the Common Toxicity Criteria Adverse Events v4.0.ResultsA total of 40 patients with 55 colorectal liver metastases were included in this study. We delivered 37.5[[ce:hsp sp="0.25"/]]Gy to 32 lesions, and 50.25[[ce:hsp sp="0.25"/]]Gy to 23 lesions. Median follow-up was 26 and 25 months for these two groups. Local control at 2 and 3 years was 74 and 66% in the low dose group while 90 and 81% was reached in the high dose group. No significant difference in local control between the two dose fractionation schemes could be found. Grade 3 toxicity was limited and was not increased in the high dose group.ConclusionsSBRT for colorectal liver metastases offers a high chance of local control at long term. High irradiation doses may contribute to enhance this effect without increasing toxicity

A nationwide assessment of hepatocellular adenoma resection:Indications and pathological discordance

Hepatocellular adenomas (HCAs) are benign liver tumors associated with bleeding or malignant transformation. Data on the indication for surgery are scarce. We analyzed indications and outcome of patients operated for HCAs 50 mm (52%), suspicion of (pre)malignancy (28%), and (previous) bleeding (5.1%). No difference was observed in HCA-subtype distribution between small and large tumors. Ninety-six (43%) patients had a postoperative change in diagnosis. Independent risk factors for change in diagnosis were tumor size <50 mm (adjusted odds ratio [aOR], 3.4; p < 0.01), male sex (aOR, 3.7; p = 0.03), and lack of hepatobiliary contrast-enhanced magnetic resonance imaging (CE-MRI) (aOR, 1.8; p = 0.04). Resection for small (suspected) HCAs was mainly indicated by suspicion of (pre)malignancy, whereas for large (suspected) HCAs, tumor size was the most prevalent indication. Male sex, tumor size <50 mm, and lack of hepatobiliary CE-MRI were independent risk factors for postoperative change in tumor diagnosis

Interstitial laser coagulation for hepatic tumours (multiple letters)

Sir,The valuable comments of Messrs Jiao and Habib allow us to emphasize the aspects of interstitial laser coagulation ILC) essential for the destruction of large volumes of tissue. Resistance of the tissue, pivotal in radiofrequency coagulation, does not cause the carbonization found with conventional laser fibres in ILC. Charringis the result of concentrated light emission at the tip with further absorption of light by the blackened tissue and preventingfurther light emission into the tissue. The argument that the characteristics of the tumour are crucial is not supported by evidence in the literature. The advantage of ILC is the induction of symmetrical and reproducible coagulation which makes the technique particularly suitable for solid intraparenchymal tumours. The lack of success in the patient with cholangiocarcinoma might be related to the diffuse spreadingpattern of the tumour rather than the high fibrous content. As stated in the review ultrasonography has no place in real-time monitoring of ILC as the echogenic area does not correlate with the coagulative damage. This is not because of charring but because the formation of gas bubbles results in a heterogeneous image. We emphasized that the use of a cylindrical light-diffusing tip in an internally water-cooled sheet combined with hepatic vascular in¯ow occlusion duringlaser treatment) results in coagulated volumes of 5 cm diameter. We hypothesize that this combination leads to a higher percentage of successful treatments in a single session when compared with the results of current application of ILC for colorectal metastases and percutaneous ethanol injection for hepatocellular carcinoma. In an ongoing study the safety, feasibility and initial response rate of percutaneous ILC with vascular inflow occlusion is beingassessed in patients with irresectable colorectal metastases or hepatocellular carcinoma largest diameter 4 cm). Triphasic contrast-enhanced spiral computed tomography is used to evaluate tumour response. In nine patients, 11 laser treatments have been performed for 13 tumours. Minor complications were noted in ®ve treatments, but complete coagulation at 24 h was 70 per cent with no failures in the last seven treated tumours. These results encourage us to determine the duration of response in a larger group of patients

Induction of specific inhibition of alloreactivity in beagle dogs by intrathymic injection of donor splenocytes

The aim of this study was to investigate whether intrathymic injection (ITI) of donor splenocytes in dogs might lead to specific immunomodulation as assessed by mixed lymphocyte culture (MLC) tests. Two groups of five beagles each were used. Group 1 contained animals that were 2 years old, group 2 consisted of animals that were 6 months old. One animal was splenectomized per experimental group and 1 x 109 splenocytes were injected into the thymic lobes or thymic remnant of the four remaining dogs. On the day of ITI the dogs were treated subcutaneously with a single dose of 2 ml/kg antilymphocyte serum (ALS). In group 1 the thymus of all dogs was found to be atrophic. ITI in this group did not result in a decreased immunoreactivity but rather in an enhanced immune response. In group 2 the thymus was still clearly present and ITI was easy to perform. ITI induced a significant reduction of specific MLC reactivity at 1 week after treatment. The effect was transient and not significantly further diminished at week 2. These results indicate that ITI is a technically feasible procedure in a preclinical animal model. It may induce temporary sensitization as well as immunosuppression, possibly depending on the age of the recipient.</p