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We introduce two rare obstetric entities. They show very similar image findings, but the prognosis is different. Prognosis is generally favorable for complete hydatidiform mole with coexisting fetus (CHMCF), but placental mesenchymal dysplasia (PMD) has high fetal and neonatal mortality. Differential diagnosis is essential to management of pregnancy. Twin pregnancies with CHMCF are characterized by the coexistence of complete mole (diploid without fetal parts) and a normal live fetus with a normal placenta. US Findings: 1. Normal fetus and normal placenta with umbilical cord insertion 2. Separated molar placenta, vesicular sonographic pattern Differential Diagnosis: Partial mole (Triploid) Hematoma in placenta (normal β-hCG level) Placental mesenchymal dysplasia Biochemistry: β-hCG concentrations are extremely high • Chorionic villus sampling can be useful to differentiate in early pregnancy between CHMCF and partial hydatidiform mole • Amniocentesis or fetal blood sampling • Genotype of a CHM is entirely of paternal origin • Management of pregnancies with CHMCF has not been standardized • Continuation of CHMCF is an acceptable option: Intensive maternal follow up ultrasonography and β-hCG level monitoring • The chance of a live birth is 7 - 37%. • Complications: Fetal death, vaginal bleeding, preeclampsia, hyperthyroidism, gestational trophoblastic neoplasia Case 1: A 31-year old woman, gravida 2, para 0 CC: IUP at 17 weeks with abnormal placenta. Serum β-hCG levels: 234,358 mIU/mL (elevated) Fetal US: IUP at 17 weeks Twin pregnancy with complete H-mole and coexisting fetus Emergency Cesarian section for fetal distress at 27 wks Delivery: Boy, Apgar score 1'-1, 5'-1 Cytogenetic report: 46, XY, normal Pathological Diagnosis: Complete hydatidiform mole with coexisting fetus Case 2: A 32-year old woman, gravida 1, para 0 CC: IVF pregnancy follow up Serum β-hCG levels: 1,873,485 mIU/mL (elevated) Fetal US: IUP at 8 weeks Twin pregnancy with complete H-mole and coexisting fetus Dilatation and evacuation for vaginal bleeding at 10 weeks Pathological Diagnosis: Complete hydatidiform mole with coexisting fetus Part I: multiple fragments of placental tissue (about 5cc) with variable sized cysts (up to 0.7cm) Part II: multiple fragments of placental tissue (5 × 3cm) without grape like cystic change Developed persistent trophoblastic disease and 18 cycle chemotherapy Case 3: A 34-year old woman, gravida 1, para 0 CC: IVF pregnancy follow up fetus Serum β-hCG levels: 306,645 mIU/mL (elevated) Fetal US: IUP at 17 weeks Twin pregnancy with complete H-mole and coexisting fetus Rare placental lesion estimated to occur in 0.02% of pregnancies. Placental enlargement, dilated and tortuous chorionic vessels, and a focal distribution of cystically enlarged villi. US Findings: Typical large and thickened with multicystic, hypoechoic areas Differential Diagnosis: Partial mole, complete hydatidiform mole with coexisting fetus (CHMCF), chorangioma, intervillous hematoma, infarct or nonspecific hydropic changes • Characteristic morphologic features • Lack of trophoblastic hyperplasia –> maternal serum β-hCG levels are not elevated or only slightly elevated • No known risk of persistent gestational trophoblastic disease • No other specific maternal serum markers • Perinatal demise: not certain, but high as 43% • Cause of fetal death: Massive fetal hemorrhage secondary to rupture of delated periumbilical chorionic vessels Case 4: A 34-year old woman, gravida 1, para 0 CC: IUP at 12 weeks weeks Twin pregnancy with complete H-mole and coexisting fetus Serum β-hCG levels: 39,249 mIU/mL Fetal US: IUP at 12 weeks Twin pregnancy with complete H-mole and coexisting fetus Chorionic Villus Sampling (12 weeks) • Normal appearing placenta: 46, XX Normal • Abnormal appearing placenta: 46, XX Normal QF-PCR: placental mesenchymal dysplasia Pathological Diagnosis: Placental mesenchymal dysplasia Case 5: A 35-year old woman, gravida 2, para 1 CC: IUP 19 weeks, abnormal enlarged and honeycomb shaped placenta Serum β-hCG levels: none Fetal US: IUP at 20 weeks Twin pregnancy with complete H-mole and coexisting fetus R/O Placental mesenchymal dysplasia Amniocenthesis: Mosaicism 47,XY +15[3]/46,XX[31] Pathological Diagnosis: Placental mesenchymal dysplasia Complete Hydatidiform Mole with Coexisting Fetus vs Placental Mesenchymal Dysplasia We proposed two differential diagnosis points 1. Proportion of two patterns of placenta - CHMCF: similar size of two patterns of placenta - PMD: dominant vesicular pattern placenta 2. Umbilical cord insertion - CHMCF: center of normal placenta - PMD: junction of two different patterns of placenta → finally insert into abnormal placenta [ABSTRACT FROM AUTHOR]

Objectives: To investigate ultrasonographic features of focal nodular hyperplasia of the liver with contrast‐enhanced ultrasonography (CEUS) using Sonazoid (perflubutane; GE Healthcare, Oslo, Norway). Methods: Thirty‐one patients with 31 focal nodular hyperplasia nodules who underwent CEUS using Sonazoid between July 2012 and February 2015 were included in this study. After the microbubble contrast agent was injected, intermittent CEUS images were obtained during the following 4 phases: arterial (10–40 seconds), portal venous (60–90 seconds), delayed (3 minutes), and Kupffer (>10 minutes). Three abdominal radiologists retrospectively reviewed the images and achieved consensus for vascular (central artery, stellate vascularity, and centrifugal enhancement) and dynamic enhancement patterns during the late arterial, portal venous, delayed, and Kupffer phases. Results: The patients included 12 men and 19 women (age range, 21–82 years; mean, 47 years). The mean diameter of the lesions ± SD was 2.2 ± 0.9 cm (range, 1.0–4.0 cm). On CEUS, 24 of 31 lesions (77.4%) showed central artery and stellate vascularity in the early arterial phase, and 25 (80.6%) showed centrifugal enhancement. Twenty‐six lesions (83.9%) were hyperechoic during the late arterial phase and showed hyperenhancement or isoenhancement during the serial dynamic phases. Kupffer‐phase images indicated that only 2 lesions (6.5%) were hypoechoic compared with surrounding liver parenchyma, whereas 29 (93.5%) remained either hyperechoic (2 [6.5%]) or isoechoic (27 [87.1%]). Conclusions: Contrast‐enhanced US using Sonazoid for focal nodular hyperplasia showed typical vascular patterns of central artery vascularity, stellate vascularity, and centrifugal enhancement. Most cases were either hyperenhanced or isoenhanced on serial dynamic‐ and Kupffer‐phase imaging. Based on these results, CEUS can provide useful information for noninvasive focal nodular hyperplasia diagnoses. [ABSTRACT FROM AUTHOR]

Purpose: To identify the most reliable imaging features for differentiating hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase (HCCpara ) from focal nodular hyperplasia (FNH)-like nodules using Gd-EOB-DTPA-enhanced MRI.Materials and Methods: This was a retrospective study. Twenty patients with HCCpara and 21 patients with FNH-like nodules were included. The following MRI features were evaluated using 3.0 Tesla unit by two radiologists: signal intensity (SI) on T1-, T2-, and diffusion-weighted imaging (DWI), arterial enhancement pattern, washout appearance on the portal venous phase (PVP) and/or transitional phase (TP), uptake pattern on the hepatobiliary phase (HBP), "T2 scar," "EOB scar," and chemical shift on in- and out-of-phase images. Multivariate logistic regression analysis was performed to assess MRI features for prediction of HCCpara .Results: Compared with FNH-like nodules, HCCpara had significantly more frequent heterogeneous T1 SI (P < 0.0001), T2 hyperintensity (P = 0.032), heterogeneous arterial enhancement (P < 0.0001), washout appearance on the PVP and/or TP (P < 0.0001), heterogeneous uptake on the HBP (P < 0.0001), absence of "EOB scar" (P < 0.0001), and hyperintensity on DWI (P = 0.004). Multivariate logistic regression analysis revealed washout appearance as the only independent imaging feature associated with HCCpara (odds ratio, 7.019; P = 0.042). Washout appearance also showed the best diagnostic performance with a sensitivity of 90% and a specificity of 100%.Conclusion: Washout appearance on the PVP and/or TP is the most reliable imaging feature for differentiating HCCpara from FNH-like nodules.Level Of Evidence: 3 J. MAGN. RESON. IMAGING 2017;45:1599-1608. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To compare the in vivo gastric injury observed during radiofrequency (RF) ablation of the liver abutting the stomach before and after the intragastric administration of chilled saline. Materials and methods: Twenty RF ablation zones were created in the livers of 10 pigs with a 1-cm-exposed active tip of an internally cooled electrode under ultrasound guidance for 10min. Ten RF ablation zones were created before (non-saline group) and after (saline group) the intragastric administration of approximately 1000mL of chilled saline, and 20 RF ablation zones were made in the posterior part of the left lobe abutting the stomach. The frequency and severity of the thermal injury observed in the stomach of the two groups were compared histologically. Results: All the resected gastric specimens showed thermal injuries of varying degrees of severity. The largest diameter of the gastric injury was significantly smaller in the saline group (mean 1.5cm; range 1.3–1.8cm) than in the non-saline group (mean 2.1cm; range 1.8–2.4cm) (p =0.000). The saline group showed significantly less thermal injury to the muscular layer of the gastric wall by the histopathology (p =0.033). Conclusions: The intragastric administration of chilled saline might be a useful technique for reducing the severity of gastric injury during RF ablation of the liver abutting the stomach. [Copyright &y& Elsevier]

Abstract: Purpose: The purpose was to describe magnetic resonance imaging (MRI) findings of breast cancer liver metastasis using gadoxetic acid (Gd-EOB-DTPA) with an emphasis on the added value of the hepatobiliary phase (HBP). Material and methods: Nine patients with 13 liver metastases were included in the study after the medical records of 29 breast cancer patients who underwent Gd-EOB-DTPA-enhanced MRI between February 2008 and June 2010 were reviewed. The diagnoses of liver metastasis were established by percutaneous liver biopsy or surgery and on the basis of image findings. Two radiologists retrospectively evaluated signal intensity (SI) and sizes of metastases and patterns of enhancement in an HBP. The SI ratio was calculated as the SI of the central hyperintense portion in “target” lesions divided by the SI of nearby normal liver parenchyma on the HBP. We also measured apparent diffusion coefficient (ADC) values from Diffusion Weighted Image (DWI). Results: Liver metastases were all hypointense [n=13/13 (100%)] on T1-weighted imaging (WI), and many lesions had a “target” appearance with a central high SI and a peripheral low SI rim (47%) on T2WI. Dynamic study showed rim enhancement on the arterial phase (85%) and a “target” appearance, consisting of a central enhancing portion with peripheral washout or hypointense rim, on the HBP (62%). The mean SI ratio was 0.7. The mean ADC value of “target” appearing metastases was 1.25 (×10−3 mm2/s; range 1.3–1.6) compared with a mean value of 0.8 (×10−3 mm2/s; range 0.8–1.4) in homogeneous defect on the HBP. There was statistically significant difference (P<.05). Conclusion: Breast cancer liver metastases commonly demonstrated as a peripheral ring enhancement on arterial dominant phase and a target sign with a central round enhancing portion and a peripheral hypointense rim on the HBP. [Copyright &y& Elsevier]

Purpose: To evaluate the sensitivity of corticomedullary-phase imaging for detecting urinary stones in patients with renal colic who visited the emergency department., Materials and Methods: This retrospective study included 253 patients with suspected renal colic from two tertiary hospitals in South Korea, who visited the emergency department and underwent CT urography. Two radiologists blinded to the clinical history independently reviewed the corticomedullary-phase images. The sensitivity for identifying urinary stones were evaluated for each reviewer. After the initial evaluation, the images were re-evaluated based on patient history. The sensitivity of re-evaluation were recorded., Results: Of 253 patients, 150 (59%) had urinary stones. Among them, significant stones were observed in 138 patients (92%), and obstructive changes on CT in 124 patients (82.7%). For identifying significant urinary stones, the sensitivity was 98.6% (136/138) for both the reviewers. For identifying significant urinary stones with urinary obstruction, the sensitivity was 99.2% (123/124) for reviewer 1, and 100% (124/124) for reviewer 2. The sensitivity for identifying significant stones increased from 98.6% to 100% for reviewer 1, and from 98.6% to 99.3% for reviewer 2 in the re-evaluation session., Conclusion: The corticomedullary-phase CT urography was sensitive for diagnosing urolithiasis in patients with acute renal colic who visited the emergency department., Competing Interests: Conflicts of Interest: The authors have no potential conflicts of interest to disclose., (Copyrights © 2023 The Korean Society of Radiology.)

Ultrasonography (US) is widely used for abdominal imaging. Its noninvasiveness, extensive range of application, and low cost make US a useful and valuable tool for the detection, diagnosis, and follow-up of splenic abnormalities. Concomitantly with the increasing frequency of imaging, more splenic lesions are being discovered and the requirements for the differential diagnosis are rising. In this pictorial essay, we introduce the representative US findings of many different splenic lesions, including normal sonographic findings, normal variants and congenital anomalies, infectious conditions, benign and malignant neoplasms, and non-neoplastic lesions. Knowledge of the US features of various splenic lesions will help narrow the differential diagnosis and guide clinical decision-making.

Purpose: To evaluate the feasibility of an abbreviated gadoxetic acid-enhanced MRI protocol including second-shot arterial phase (SSAP) imaging for liver metastasis evaluation., Materials and Methods: For this retrospective study, a total of 197 patients with cancer (117 men and 80 women; mean age, 62.9 years) were included who underwent gadoxetic acid-enhanced MRI performed by using a modified injection protocol for liver metastasis evaluation from July to August 2017. The modified injection protocol included routine dynamic imaging after a first injection of 6 mL and SSAP imaging after a second injection of 4 mL. Image set 1 was obtained with the full original protocol. Image set 2 consisted of T2-weighted, diffusion-weighted, hepatobiliary phase, and SSAP images (the simulated abbreviated protocol). Acquisition time was measured in each image set. The diagnostic performance of each image set was compared by using a jackknife alternative free-response receiver operating characteristic analysis. Image quality evaluation and visual assessment of vascularity were performed on the original arterial phase images, the SSAP images, and their subtraction images., Results: The acquisition time was significantly shorter in image set 2 than in image set 1 (18.6 vs 6.2 minutes, P <.0001). The reader-averaged figure-of-merit was not significantly different between image sets 1 and 2 ( P = .197). The mean motion artifact score was significantly lower for the SSAP images than for the original arterial phase images ( P <.001). All hypervascular metastases ( n = 72) showed hyperintensity on the SSAP and/or the second subtraction images., Conclusion: An abbreviated MRI protocol including SSAP is feasible for liver metastasis evaluation, providing faster image acquisition while preserving diagnostic performance, image quality, and visual vascularity. Keywords: Abdomen/GI, Comparative Studies, Liver, MR-Imaging, Metastases© RSNA, 2019 Supplemental material is available for this article., Competing Interests: Disclosures of Conflicts of Interest: J.W.K. disclosed no relevant relationships. C.H.L. disclosed no relevant relationships. Y.S.P. disclosed no relevant relationships. J.L. disclosed no relevant relationships. K.A.K. disclosed no relevant relationships., (2019 by the Radiological Society of North America, Inc.)

Purpose: This study aimed to evaluate the impact of body habitus factors on image quality of low-tube voltage computed tomography (CT) during the hepatic arterial phase., Materials and Methods: Ninety-seven patients (66 men, 31 women; age range, 26-78 years) who underwent clinically indicated liver dynamic CT examination were enrolled in the study. Analysis with 80-kVp CT and intermediate tube current (277-337 mA) was performed in the late hepatic arterial phase using a 320-detector row scanner with adaptive iterative dose reduction 3-dimensional reconstruction. Patient body habitus was measured using body weight (BW), body mass index (BMI), lateral width (LW) of the abdomen, and muscle volume (MV) of the abdominal wall. On hepatic arterial phase, the mean image noise and contrast-to-noise ratio (CNR) for the aorta and liver were assessed. The correlations between body habitus factors and image quality parameters were evaluated., Results: In all patients, MV showed the strongest correlation with image noise, followed by BW and LW (r = 0.684, 0.570, and 0.555, respectively). The BMI showed the fourth strongest correlation with image noise among all body habitus factors (r = 0.377). With respect to CNR of the aorta, MV and BW showed the strongest inverse correlation (r = -0.590 and -0.600, respectively), followed by LW and BMI (r = -0.557 and -0.423, respectively). Regarding the CNR of the liver, MV showed the strongest inverse correlation (r = -0.279), although the correlation efficiency was weak compared with other correlations., Conclusions: Among various body habitus factors, MV showed the strongest association with image noise and CNR in the hepatic arterial phase using 80-kVp CT.

Objective: The aim of this study was to assess whether a short breath-hold technique can improve hepatic arterial phase (HAP) image quality in gadoxetic acid-enhanced magnetic resonance (MR) imaging compared with a conventional long breath-hold technique., Materials and Methods: Institutional review board approval and patient consent were obtained for this prospective randomized control study. One hundred nineteen patients undergoing gadoxetic acid-enhanced MR imaging were randomly assigned to groups A or B. Group A patients underwent an 18-second long breath-hold MR technique (conventional VIBE [volumetric interpolated breath-hold examination] technique with GRAPPA [generalized autocalibrating partially parallel acquisition]), and group B patients underwent a 13-second short breath-hold MR technique (VIBE technique with CAIPIRINHA [controlled aliasing in parallel imaging results in higher acceleration]). Respiratory-related graphs of the precontrast and HAP were acquired. The breath-hold degree was graded based on the standard deviation (SD) value of respiratory waveforms. Gadoxetic acid-related dyspnea was defined as when the SD value of the HAP was 200 greater than that of the precontrast phase without degraded image quality in the portal and transitional phases (SD value of the HAP - SD value of the precontrast phase). The overall image quality and motion artifacts of the precontrast and HAP images were evaluated. The groups were compared using the Student t or Fisher exact test, as appropriate., Results: The incidence of breath-holding difficulty (breath-hold grades 3 and 4) during the HAP was 43.6% (27/62) and 36.8% (21/57) for group A and B, respectively. The SD value during the precontrast phase and the SD value difference between the precontrast and HAP were both significantly higher in group A than in group B (P = 0.047 and P = 0.023, respectively). Gadoxetic acid-related dyspnea was seen in 19.4% (12/62) of group A and 7.0% (4/57) of group B. Group B showed better precontrast and HAP image quality than group A (P < 0.001). Degraded HAP (overall image quality ≥4) was observed in 9.7% (6/62) and 3.5% (2/57) of group A and B, respectively., Conclusions: The short breath-hold MR technique, CAIPIRINHA, showed better HAP image quality with less degraded HAP and a lower incidence of breath-hold difficulty and gadoxetic acid-related dyspnea than the conventional long breath-hold technique.

Objective: The objective of this study was to retrospectively determine the findings of Gd-EOB-DTPA (gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid)-enhanced magnetic resonance imaging (MRI) to distinguish abscess from metastasis of the liver., Methods: Among patients who underwent Gd-EOB-DTPA MRI from March 2008 to December 2011, 32 patients with abscess or metastasis were included, and all lesions showed arterial rim enhancement. Twenty-one abscesses and 19 metastases were included. Two radiologists assessed how the arterial enhancing rim showed in hepatobiliary phase (HBP) and classified the signal intensity of the rim into defect zone, gray zone, and uptake zone. The frequency of showing nondefect, which means gray or uptake zone between both lesions, was compared using Pearson χ test., Results: The rim of arterial enhancement in 3 abscesses (14.3%) and 15 metastases (78.9%) showed defect zone in HBP. Six abscesses (28.6%)and no metastases showed gray zone, and 12 abscesses (57.1%) and 4 metastases (21.1%) showed uptake zone. The frequency of nondefect in the rim of arterial enhancement on HBP was significantly higher in abscesses (85.7% of abscesses, 21.1% of metastases, P < 0.001)., Conclusions: A reliable finding that distinguished abscess from metastasis was nondefect of arterial enhancing rim on HBP in Gd-EOB-DTPA MRI. This is a meaningful feature for differentiating abscess from metastasis, especially when evaluating patients with primary malignancy.

Aim: To evaluate the relationship between hepatic fat infiltration and abdominal fat volume by using computed tomography (CT)., Methods: Three hundred and six patients who visited our obesity clinic between November 2007 and April 2008 underwent fat protocol CT scans. The age range of the patients was 19 to 79 years and the mean age was 49 years. The male to female ratio was 116:190. Liver and spleen attenuation measurements were taken with three regions of interests (ROIs) from the liver and two ROIs from the spleen. Hepatic attenuation indices (HAIs) were measured as follows: (1) hepatic parenchymal attenuation (CT(LP)); (2) liver to spleen attenuation ratio (LS ratio); and (3) difference between hepatic and splenic attenuation (LS(dif)). Abdominal fat volume was measured using a 3 mm slice CT scan starting at the level of the umbilicus and was automatically calculated by a workstation. Abdominal fat was classified into total fat (TF), visceral fat (VF), and subcutaneous fat (SF). We used a bivariate correlation method to assess the relationship between the three HAIs and TF, VF, and SF., Results: There were significant negative correlations between CT(LP), LS ratio, and LS(dif) with TF, VF, and SF, respectively. The CT(LP) showed a strong negative correlation with TF and VF (r = -0.415 and -0.434, respectively, P < 0.001). The correlation between CT(LP) and SF was less significant (r = -0.313, P < 0.001)., Conclusion: Fatty infiltration of the liver was correlated with amount of abdominal fat and VF was more strongly associated with fatty liver than SF.

Objective: This study was designed to compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine-enhanced MRI for preoperatively detecting hepatocellular carcinoma (HCC)., Materials and Methods: Eighteen consecutive patients (17 men and one woman, age range: 31-73 years) with 22 HCCs underwent examinations with gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI on a 3.0-Tesla unit. The diagnosis of HCC was established after surgical resection and pathological conformation. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC was assessed by performing an alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated., Results: The average value of the area under the ROC curve (Az) for gadoxetic acid enhanced MRI (0.887) was not significantly different from the Az (0.899) for gadobenate dimeglumine-enhanced MRI (p > 0.05). The overall sensitivities of gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI were 80% and 83%, respectively, with no significant difference (p > 0.05). The differences of the positive predictive values for the two contrast agents for each observer were not statistically significant (p > 0.05)., Conclusion: The diagnostic performance of gadoxetic acid-enhanced MRI and gadobenate dimeglumine-enhanced MRI for preoperatively detecting HCC is quite similar.

The cystic lesions of the gastrointestinal (GI) tract demonstrate the various pathologic findings. Some lesions may present a diagnostic challenge because of non-specific imaging features; however, other lesions are easily diagnosed using characteristic radiologic features and anatomic locations. Cystic masses from the GI tract can be divided into several categories: congenital lesions, neoplastic lesions (cystic neoplasms, cystic degeneration of solid neoplasms), and other miscellaneous lesions. In this pictorial review, we describe the pathologic findings of various cystic lesions of the GI tract as well as the radiologic features of GI cystic lesions from several imaging modalities including a barium study, transabdominal ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging.

We compared the diagnostic performance of ferucarbotran-enhanced magnetic resonance imaging (MRI) with that of gadoxetic acid-enhanced MRI for the preoperative detection of hepatocellular carcinoma (HCC) of 27 consecutive patients (male-female, 21:6; 33-76 years) with 38 surgically proven HCCs (mean diameter, 2.8 cm; range, 0.8-10.2 cm) on a 3.0-T unit. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC, sensitivity, positive and negative predictive values was evaluated. For each observer, the values of the area under the receiver operating characteristic curve (Az) were 1.000, 1.000, and 0.974 for ferucarbotran-enhanced MRI and 1.000, 0.987, and 1.000 for gadoxetic acid-enhanced MRI, and the differences were not statistically significant between 2 techniques for each observer (P > 0.05). For each observer, sensitivities were 100%, 100%, and 92.1% for ferucarbotran-enhanced MRI and 100%, 94.7%, and 100% for gadoxetic acid-enhanced MRI with no statistical significance (P > 0.005). The differences of the positive and negative predictive values of 2 techniques for each observer were not statistically significant (P > 0.05). Ferucarbotran-enhanced MRI and gadoxetic acid-enhanced MRI show a similar diagnostic performance for the preoperative detection of HCCs.

Objective: The purpose of this article is to describe the "pseudo washout" sign of high-flow hepatic hemangioma that mimics hypervascular tumor on gadoxetic acid-enhanced MRI., Conclusion: High-flow hemangiomas might show relatively low signal intensity because of gadoxetic acid contrast uptake in the surrounding normal liver parenchyma during the equilibrium (3-minute delay) phase. Such findings are called pseudo washout and can mimic hypervascular hepatic tumors. However, high-flow hemangioma can be diagnosed by observing bright signal intensity on T2-weighted imaging, arterial phase-dominant enhancement, pseudo washout sign during the equilibrium phase, and isointense or slightly increased signal intensity on subtraction images.

Objective: We compared the diagnostic performance of gadoxetic acid-enhanced MRI with that of triple-phase 16-, 40-, and 64-MDCT in the preoperative detection of hepatocellular carcinoma (HCC)., Subjects and Methods: Sixty-two consecutively registered patients (54 men, eight women; age range, 31-67 years) with 83 HCCs underwent triple-phase (arterial, portal venous, equilibrium) CT at 16-, 40-, or 64-MDCT and gadoxetic acid-enhanced 3-T MRI. The diagnosis of HCC was established after surgical resection. Three observers independently and randomly reviewed the MR and CT images on a tumor-by-tumor basis. The diagnostic accuracy of these techniques in the detection of HCC was assessed with alternative free response receiver operating characteristic (ROC) analysis. Sensitivity, positive and negative predictive values, and sensitivity according to tumor size were evaluated., Results: For each observer, the areas under the ROC curve were 0.971, 0.959, and 0.967 for MRI and 0.947, 0.950, and 0.943 for CT. The differences were not statistically significant between the two techniques for each observer (p > 0.05). The differences in sensitivity and positive and negative predictive values between the two techniques for each observer were not statistically significant (p > 0.05). Among 10 HCCs 1 cm in diameter or smaller, each of the observers detected seven tumors with MRI. With CT, one observer detected five, one observer detected four, and one observer detected three HCCs with no statistically significant difference (p > 0.05)., Conclusion: Gadoxetic acid-enhanced MRI and triple-phase MDCT have similar diagnostic performance in the preoperative detection of HCC, but MRI may be better than MDCT in the detection of HCC 1 cm in diameter or smaller.

Objective: To evaluate the three-phase helical CT features of early hepatocellular carcinomas, based on the new Japanese classification., Materials and Methods: Over the course of an eight-year period, we collected 16 pathologically proven early hepatocellular carcinomas from 16 patients having undergone a three-phase helical CT prior to surgery. The three-phase CT images were acquired at 20-35 sec (arterial phase), 70 sec (portal phase), and 180 sec (equilibrium phase) from the beginning of intravenous injection of contrast material. All the CT images were retrospectively analyzed by two radiologists in consensus, based on their description of morphologic (size, margin, fibrous capsule and mosaic pattern) and enhancement patterns of tumors., Results: Only seven (44%) of the 16 early hepatocellular carcinomas having undergone a CT were described (mean diameter, 1.2 cm; range, 0.4-2.5 cm). All the tumors had an ill-defined margin with no fibrous capsule. The mosaic pattern was found in only one tumor. Only three (43%) of the seven tumors detected on CT were hyperattenuating during the arterial phase. The four remaining tumors (25%) were hypoattenuating throughout the three phases., Conclusion: Despite the higher resolution provided by the three phase scans, the contrast-enhanced CT provides only limited detection of the variable morphologic and enhancement features of early hepatocellular carcinomas.

Objective: To compare diagnostic performance of ferucarbotran-enhanced 3.0-T magnetic resonance (MR) imaging using parallel imaging technique with that of triple-phase multidetector row computed tomography (MDCT) for the preoperative detection of hepatocellular carcinoma (HCC)., Methods: Eighty-six consecutive patients with a total of 128 surgically proven HCCs were enrolled in this study. All patients underwent ferucarbotran-enhanced 3.0-T MR imaging using parallel imaging technique and triple-phase MDCT before hepatic resection. Three experienced radiologists independently analyzed each images on a segment-by-segment basis. The accuracy of these techniques for the detection of HCC was assessed by performing a receiver operating characteristic (ROC) analysis of 104 resected hepatic segments with at least 1 HCC and 113 resected hepatic segments without HCC., Results: The mean value of the area under the ROC curve (Az) of the ferucarbotran-enhanced 3.0-T MR imaging (0.990) was significantly higher than that of the triple-phase MDCT (0.964) (P = 0.00). The mean sensitivity of the ferucarbotran-enhanced 3.0-T MR imaging (98.1%) was significantly higher than that of the triple-phase MDCT (92.9%) (P = 0.00). The higher sensitivity was largely attributable to a greater ability of the 3.0-T MR imaging to detect small HCC (< or =1 cm) (92.6% in 3.0-T MR imaging and 37.0% in MDCT; P = 0.00). No significant difference was found for their mean specificities (98.2% in 3.0-T MR imaging and 97.6% in MDCT; P = 0.86)., Conclusions: Ferucarbotran-enhanced 3.0-T MR imaging using parallel imaging technique is a more accurate diagnostic tool than triple-phase MDCT for the preoperative detection of HCC. Ferucarbotran-enhanced 3.0-T MR imaging has a higher sensitivity than triple-phase MDCT, especially for small HCCs (< or =1 cm).