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Objective The purpose of this study was to examine the relationship between the CT features of the primary-site gastric cancer and the concurrent existence or postoperative recurrence of hepatic metastasis. Materials and methods From January 2013 to July 2016, 125 patients with advanced gastric cancer who were evaluated by gastroscopy and contrast-enhanced CT at our institution were included. Eleven patients had hepatic metastasis at the time of diagnosis (synchronous hepatic metastasis). Five patients had hepatic recurrence after surgery (metachronous hepatic metastasis, median follow-up period of 313 days), and another 56 patients had no hepatic recurrence during follow-up period (negative hepatic metastasis, median follow-up period of 1102 days). Two radiologists independently reviewed the CT images and they determined the peak enhancement phase, and then measured the CT attenuation value of the gastric lesion for each phase. We compared the parameters of synchronous, metachronous and negative hepatic-metastasis. We calculated diagnostic performance of CT for diagnosing synchronous and metachronous hepatic metastasis. Results The peak enhancement was significantly diff ;erent between the three groups for both readers (reader 1, p = 0.0001; reader 2, p = 0.0002). Most of the synchronous and metachronous hepatic metastasis had peak enhancement in the arterial or portal phase. The CT attenuation values of synchronous and metachronous hepatic metastasis were significantly higher than those of negative hepatic metastasis in the delayed phase according to both readers (reader 1, p = 0.0003; reader 2, p = 0.0002). In predicting synchronous hepatic metastasis using peak enhancement, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 72.7%, 89.3%, 57.1%, 94.3%, and 86.6% for reader 1, and 54.5%, 94.6%, 66.7%, 91.4%, and 88.1% for reader 2. In predicting metachronous hepatic metastasis, the sensitivity, specificity, PPV, NPV, and accuracy were 60.0%, 89.3%, 33.0%, 94.3%, and 86.9% for reader 1, and 40.0%, 94.6%, 40.0%, 94.6%, and 90.2% for reader 2. Conclusion Our study showed that gastric cancer with synchronous and metachronous hepatic metastasis tends to show early enhancement with a washout pattern on contrast-enhanced CT. This feature would be helpful in image surveillance for synchronous or metachronous hepatic metastasis of gastric cancer.

Objective To compare the accuracy of acquired diffusion weighted imaging (DWI) ( b = 1000 s/mm 2 ) with that of computed DWI ( b = 1000 s/mm 2 ) for the detection of hepatic metastases. Methods Two hundred and sixty patients underwent abdominal magnetic resonance imaging (MRI) at 3.0 T for the evaluation of hepatic metastasis, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI, DWI with b -values of 0, 500, 1000 s/mm 2 , and three-dimensional dynamic contrast-enhanced MRI with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), and 190 patients were included in the final study. Computed DWI (=1000 s/mm 2 ) was synthesized from lower b -values ( b = 0 and 500 s/mm 2 ). Two groups were assigned and compared: group A (acquired DWI) and group B (computed DWI). Diagnostic performance using each imaging set was evaluated by receiver operating characteristic (ROC) curve analysis. Results A total of 76 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B (Observer 1; 0.919–0.915, Observer 2; 0.926–0.901), but there were no significant differences (observer 1, P = 0.500; observer 2, P = 0.190). There were 5 metastases visualized in group A, but these were difficult to detect in group B. However, there were 2 metastases that were better visualized in group B than in group A. Conclusion There were no significant differences between acquired DWI and computed DWI in the detection of hepatic metastasis.

Aim To determine the T 2 relaxation time of colorectal hepatic metastases and changes in T 2 relaxation times following chemotherapy. Materials and methods 42 patients with 96 hepatic colorectal metastases underwent baseline MRI. Axial T 1 , T 2 and multi-echo GRASE sequences were acquired. ROIs were drawn on T 2 relaxation maps, obtained from GRASE images, encompassing metastasis and normal liver to record T 2 relaxation time values. In 11 patients with 28 metastases, MRI was repeated using same protocol at 6 weeks following chemotherapy. The median pre-treatment T 2 values of metastases and normal liver were compared using the Mann–Whitney test. The pre- and post-treatment median T 2 values of metastases were compared using the Wilcoxon–Rank test for responding ( n =16) and non-responding ( n =12) lesions defined by RECIST criteria. The change in T 2 values (Δ T 2 ) were compared and correlated with percentage change in lesion size. Results There was no difference in the pre-treatment median T 2 of metastases between responding (67.3±8.6) and non-responding metastases (71.4±16.5). At the end of chemotherapy, there was a decrease in the median T 2 of responding lesions (61.6±12.6) p =0.83, and increase in non-responding lesions (76.2±18.4) p =0.03, but these were not significantly different from the pre-treatment values. There was no significant difference in Δ T 2 of responding and non-responding lesions ( p =0.18) and no correlation was seen between size change and Δ T 2 (coefficient=0.3). Conclusion T 2 relaxation time does not appear to predict response of colorectal liver metastasis to chemotherapy.

Purpose To determine specific imaging features of hepatic metastasis from colorectal cancer, focusing on the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI. Materials and methods Over a 2-year period, 79 hepatic metastatic lesions were identified from 32 patients (22 men and 10 women) who proven colorectal cancer and underwent gadoxetic acid-enhanced 3.0 T MRI. Hepatic metastases were proven pathologically in 16 patients: by surgical liver resection ( n = 14) and by US-guided biopsy ( n = 2). The remaining 16 patients were considered to have hepatic metastasis based on imaging studies and clinical information. Two radiologists evaluated the imaging features of each MRI sequence, including high resolution T2WI, dynamic contrast enhancement study with hepatobiliary phase, and diffusion weighted image. We also compared SI of the lesions on T2WI and HBP. Results T2WI showed homogeneous high SI ( n = 25; 31.7%), target appearance ( n = 3; 3.8%), reversed target appearance ( n = 2; 2.6%), and heterogeneously high SI ( n = 49; 62%). On HBP, homogeneous defect were seen in 22 lesions (27.9%), target appearance in five lesions (6.4%), reversed target appearance in two lesions (2.5%), and heterogeneous defect in 50 lesions (63.3%); including reticular (70%), partially globular (26%), and diffuse GGO-like (4%) patterns. According to the imaging features on HBP, the homogeneous defect and heterogeneous defect groups had a mean ADC value of 0.99 × 10 −3 and 1.07 × 10 −3 mm 2 /s, respectively, without statistically significant difference. Conclusion Hepatic metastasis from colorectal cancer usually showed as a heterogeneous defect on HBP and a heterogeneous high SI on T2WI. The generally accepted “true defect” was not a common finding in hepatic metastasis from colorectal cancer.

Purpose To evaluate the magnetic resonance (MR) imaging feature of suspected hepatic metastasis in patients with malignant melanoma which showed intermediate findings on screened contrast-enhanced computed tomography (CECT). Materials and methods MR imaging was performed in 38 patients (22 men, 16 women; mean age, 58 years) whose CECT findings were intermediate. Hepatic metastases had been diagnosed on MR imaging in 23 of the 38 patients. Verification of hepatic metastasis was made by histological examination: ultrasonographic-guided needle biopsy (n = 3), autopsy (n = 3), and surgical resection (n = 1), or by an obvious progression in number and/or size of the lesions on follow-up MR imaging (n = 24). Two diagnostic radiologists reviewed MR images by consensus. The median follow-up duration was 14.2 months. Results Abnormal findings were detected in 31 patients on MR images, and undetected in the remaining seven patients resulting in false-positive on CECT. The mean size of the lesion was 11.0 mm. False-positive results were obtained in two lesions which disappeared on follow-up MR imaging. In six patients, lesions were considered as hepatic cysts on MR images. As a result, a total of 35 hepatic metastases were detected on MR images. Of these, 18 patients demonstrated typical melanotic appearance on MR images which showed shortened T1 and T2 relaxation times, and five patients demonstrated atypical melanotic appearance. In 16 patients, extra-hepatic metastases were also developed. Conclusion MR imaging could rule out hepatic metastasis in patients with malignant melanoma which showed intermediate findings on screened CECT, and could detect additional extra-hepatic metastases.

Purpose To compare the mangafodipir trisodium (MnDPDP)-enhanced and ferucarbotran-enhanced magnetic resonance imaging (MRI) for the detection of hepatic metastases. Material and methods Twenty patients with known hepatic metastasis underwent MR imaging using mangafodipir trisodium and ferucarbotran in at least 1-day intervals. Thirty-eight metastases were confirmed either histologically or clinically. Two radiologists independently reviewed the MnDPDP-enhanced and ferucarbotran-enhanced sets in a random order. The sensitivity and accuracy of lesion detection and the ability to distinguish a benign lesion from a malignant lesion were compared by the areas (Az) under the receiver operating characteristic (ROC) curve. The lesion-liver contrast-to-noise ratios (CNR) were compared by paired t-test. Results The overall accuracy for detecting metastases was not significantly different between the MnDPDP set (Az = 0.912 and 0.913 for reader 1 and 2, respectively) and the SPIO set (Az = 0.920 and 0.950). The CNR at the MnDPDP-enhanced images and the SPIO-enhanced images were not significantly different (P = 0.146). Conclusion Both MnDPDP- and ferucarbotran-enhanced MRI have a comparable accuracy in detecting hepatic metastasis.