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Objectives: Second shot arterial phase (SSAP) imaging is an additional arterial phase image obtained by re-injecting a small amount of contrast medium after routine dynamic imaging in gadoxetic acid-enhanced liver MRI. We aimed to evaluate the feasibility and additional value of a SSAP image in gadoxetic acid-enhanced liver MRI., Methods: One hundred seventy-two patients who underwent SSAP imaging after re-injection of 4 mL of contrast material after routine dynamic imaging (original) in gadoxetic acid-enhanced liver MRIs were included. Motion artifacts on arterial phase (AP) images were rated using a 5-point scale and were compared between the original AP images and SSAP images. We evaluated visual detection rates of arterial hypervascularity on the original AP and SSAP images and their subtraction images in patients with hypervascular hepatocellular carcinoma (HCC)., Results: The motion artifact of the SSAP images was significantly lower than that of the original AP images (mean score, 1.76 vs 2.06; p < 0.001). In particular, motion artifacts reduced significantly in the SSAP images of patients with substantial motion artifacts in their original AP images (2.28 vs 3.28; p < 0.001). Among the 30 HCC lesions showing hypervascularity on original AP images, only four (4/30, 13.3%) appeared hyperintense on SSAP images. However, subtraction images of SSAP clearly demonstrated arterial hypervascularity in all HCCs., Conclusion: SSAP images showed significantly fewer motion artifacts than the original AP images. Subtraction images of SSAP maintained the detectability of arterial hypervascularity, although SSAP images showed poor visual detection of arterial hypervascularity of HCC., Key Points: • Arterial phase images obtained after a second injection of a small amount of contrast medium (second shot arterial phase [SSAP]) improved motion artifacts compared to the original AP images. • The motion artifacts improved significantly in the SSAP images of patients with substantial motion artifacts in their original AP images. • Subtraction images of SSAP demonstrated the arterial hypervascularity characteristic of HCC at a level comparable to that of the original AP image.

Objective: The aim of this study was to describe magnetic resonance imaging findings of newly categorized ovarian seromucinous tumors., Methods: We retrospectively reviewed the images of 29 patients with seromucinous tumor for the following factors: size, configuration, signal intensity (SI), and accompanying ovarian endometriosis., Results: Thirty-two tumors (17 benign, 7 borderline, 8 carcinoma) were found on computed tomography or magnetic resonance imaging. Their mean size was 11.4 cm. Benign tumors appeared as unilocular or multilocular cystic masses. Borderline tumors and carcinomas appeared as complex cystic-solid masses. T2-weighted SI of the solid portion was hyperintense in borderline tumors and intermediate in carcinomas. Endometriosis was present in 18 tumors, and hemorrhage (on images) in 20., Conclusions: The imaging features of seromucinous tumors varied by tumor type. More than half of tumors were accompanied by endometriosis. High T2-weighted SI of the solid portion could be a specific feature of borderline tumors. It is hard to differentiate seromucinous carcinomas from other endometriosis-related carcinomas.

Purpose: To identify the most reliable imaging features for differentiating hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase (HCC para ) from focal nodular hyperplasia (FNH)-like nodules using Gd-EOB-DTPA-enhanced MRI., Materials and Methods: This was a retrospective study. Twenty patients with HCC para 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 HCC para ., Results: Compared with FNH-like nodules, HCC para 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 HCC para (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 HCC para from FNH-like nodules., Level of Evidence: 3 J. MAGN. RESON. IMAGING 2017;45:1599-1608., (© 2016 International Society for Magnetic Resonance in Medicine.)

Objectives: To determine the prognostic value of Gd-EOB-DTPA MRI findings of liver metastasis from breast cancer., Methods: 29 metastatic lesions from 12 breast cancer patients who received chemotherapy were retrospectively reviewed. We evaluated hepatobiliary phase of the lesions and classified them as a "target" or "non-target" appearance. The relationship of appearance or SI ratio with tumor response was analyzed., Results: A non-target appearance was more frequent in disease control group than in non-control group [14/18 (77.8%) vs. 4/18 (22.2%)], and it was associated with a better response [p=0.048]., Conclusion: HBP analysis may be useful to predict the response to chemotherapy and survival., (Copyright © 2017 Elsevier Inc. All rights reserved.)

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.

Objectives: To compare diagnostic accuracy of gadoxetic acid-enhanced magnetic resonance imaging (MRI) (original set) and original MRI combined with the arterial phase of low-tube-voltage computed tomography (CT) (hybrid set)., Methods: In hybrid set, we substituted the CT arterial phase for MRI arterial phase. Three observers independently interpreted. The accuracy of each image set was evaluated using the alternative-free response receiver operating characteristic method., Results: The mean Az values for original set (0.96±0.01) was higher than that for hybrid set (0.94±0.01), but the difference was not significant (P=.10)., Conclusions: In cases with degradation of magnetic resonance arterial phase, reuse of CT arterial phase might be helpful instead of repeating MRI., (Copyright © 2015 Elsevier Inc. All rights reserved.)

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.

Purpose: The purpose of the study was to determine significant imaging features to differentiate between infiltrative hepatocellular carcinoma (HCC) and confluent fibrosis (CF) in liver cirrhosis using Gd-EOB-DTPA-enhanced 3-T magnetic resonance imaging., Material and Methods: Nineteen infiltrative HCCs and eight CFs were included. We evaluated the difference in imaging findings and apparent diffusion coefficient (ADC) between the two entities. We compared T2-weighted image (WI) and hepatobiliary phase (HBP) in terms of the clarity of the lesion outer margin., Results: Seventeen infiltrative HCCs showed lobulated margin, while focal CFs showed either straight (n=3) or irregular margins (n=5) (P=.001). All infiltrative HCCs had intact or bulging contours, and all focal CFs showed capsular retraction (P=.001). Fourteen infiltrative HCCs and two focal CFs showed arterial enhancement (P=.035). The ADC of infiltrative HCCs was significantly lower than that of CFs (P=.001). Satellite nodules were noted in 10 infiltrative HCCs. In terms of outer margin clarity, infiltrative HCCs showed a more distinct margin on HBP than on T2-WI (P=.005), while these two sequences were not significantly different in focal CFs (P=1.000)., Conclusion: HBP improved the imaging characteristics of infiltrative HCC, allowing it to be distinguished from focal CF. Infiltrative HCC showed lower ADC values than focal CF. Lobular configuration, contour bulging, enhancement pattern, associated satellite nodules and portal vein thrombosis were still found to be highly suggestive MR findings for infiltrative HCC., (Copyright © 2013 Elsevier Inc. All rights reserved.)

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 3.0T 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., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

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) mm(2)/s; range 1.3-1.6) compared with a mean value of 0.8 (×10(-3) mm(2)/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 © 2012 Elsevier Inc. All rights reserved.)

Purpose: To assess factors affecting tumor visibility on planning ultrasound (US) for percutaneous radiofrequency (RF) ablation to treat small hepatocellular carcinomas (HCCs) primarily detected on computed tomography (CT) or magnetic resonance (MR) imaging., Materials and Methods: Patients referred for planning US for percutaneous RF ablation between September 2008 and June 2009 were prospectively enrolled from nine institutions in Korea. The first small (≤ 3 cm) single HCC or new single HCC after treatment was included. The study enrolled 898 patients (684 men and 214 women, age range 32-86 years). HCCs that were invisible on planning US were compared with visible HCCs with respect to tumor size, distance between the tumor and the diaphragm, subcapsular location, etiology of liver disease, liver cirrhosis, macronodular cirrhosis on US, ascites, Child-Pugh class, serum alpha fetoprotein (AFP) level, body mass index (BMI), previous treatments for HCC, previous chemoembolization treatments for HCC, institutions, and experience of radiologists., Results: Among 898 HCCs, 671 (74.7%) were visible on the planning US. In multivariate analysis, tumor size, distance between the tumor and the diaphragm, liver cirrhosis, and macronodular cirrhosis were statistically significant factors affecting US detection (each P < .05)., Conclusions: Smaller tumors, subphrenic location of the tumor, liver cirrhosis, and macronodular cirrhosis were independent predictors of invisible tumors on planning US., (Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To validate the diagnostic performance of quadruple phase low tube voltage liver CT through the comparison with Gd-EOB-DTPA enhanced liver MRI for the detection of HCC., Materials and Methods: Non-obese patients (38 men, eight women) with 68 HCCs underwent quadruple-phase CT at 16 MDCT (using low tube voltage, 80kVp; moderately high tube current, 280mAs) and Gd-EOB-DTPA-enhanced 3T MRI. Three observers independently and randomly reviewed the CT and MR images on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for detecting HCC was assessed using alternative free-response receiver operating characteristic analysis. Sensitivity and positive predictive values were evaluated. The mean effective doses for the low dose CT were also evaluated., Results: The areas under the ROC curves were 0.963, 0.959, and 0.941 for low dose CT and 0.981, 0.982, and 0.976 for MRI. Differences in Az of the two techniques for each observer were not statistically significant (P>.05). Differences in sensitivity and positive predictive values between the two techniques for each observer were not also statistically significant: sensitivity (86.8%, 82.4%, 85.3% for CT and 95.6%, 94.1%, 91.2% for MRI) and positive predictive values (92.2%, 90.3%, 89.2% for CT and 92.9%, 92.8%, 92.5% for MRI). Six HCCs (8.8%) in five patients were observed only on hepatobiliary phase of MRI, and all were smaller than 1.5cm. The mean effective dose for CT was approximately 10.2mSv., Conclusions: Quadruple-phase low-dose liver CT (80kVp, 280mAs) had relatively good diagnostic performance for detecting HCC in non-obese patients. Because no significant difference was observed between low-dose CT and MRI, the use of low-dose liver CT can be justified based on its reduced radiation effects., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To describe the paradoxical high signal intensity of hepatocellular carcinoma (HCC) in the hepatobiliary phase on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI)., Materials and Methods: A database search was performed to identify cases of HCC that showed unusual prolonged enhancement in the hepatobiliary phase of Gd-EOB-DTPA MRI. All patients received 3.0-T liver MRI including precontrast T1-weighted images, T2-weighted images and a post Gd-EOB-DTPA-enhanced dynamic study. The signal intensity of HCC was measured at pre-enhanced, arterial, portal, delayed and hepatobiliary phase using regions of interest. Radiologic and pathologic correlation was performed for the paradoxically prolonged enhancing portion of HCC in the hepatobiliary phase., Results: Four patients (all male, age range 44-70; mean 57.5 years) were included in this study. All patients showed HCC lesions that were low signal intensity (SI) on T1-WI, high SI on T2-WI, enhanced in arterial phase, and washed-out in delayed phase. All cases showed paradoxically high SI in hepatobiliary phase, which was unusual for HCC. Pathologically, they were all diagnosed as well-differentiated HCC with prominent cytoplasm and a bile secreting appearance., Conclusion: HCC may demonstrate the prolonged high signal intensity at the hepatobiliary phase on Gd-EOB-DTPA enhanced MRI. These HCCs tended to be highly differentiated and to have prominent bile secretion., (Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to describe magnetic resonance (MR) findings of focal eosinophilic liver disease using gadoxetic acid (Gd-EOB-DTPA)., Materials and Methods: Nineteen patients (M:F=14:5; age range, 26-66 years; mean age, 50 years) with 35 focal eosinophilic liver lesions were included after reviewing the medical records of 482 patients who underwent Gd-EOB-DTPA-enhanced MR imaging (MRI) on a 3.0-T unit between April 2008 and June 2009. The diagnosis of focal eosinophilic liver disease was established by means of percutaneous liver biopsy or surgery and consistent clinical findings. Two radiologists retrospectively reviewed MR images with consensus. Margin, shape and distribution of the lesions were analyzed. We also evaluated signal intensity of focal hepatic lesions on T(1)- and T(2)-weighted images and patterns of enhancement in dynamic contrast study., Results: The mean diameter of the lesions was 1.7 cm (range, 0.7-6.1 cm). Most of the focal eosinophilic liver lesions [n=31/35 (88.6%)] had poorly defined margins. They were usually isointense or slightly hypointense [n=34/35 (97.2%)] on T(1)-weighted images and hyperintense [n=32/35 (91.4%)] on T(2)-weighted images. Dynamic study showed enhancement (rim or homogeneous) on the arterial phase [n=21/35 (60%)] and hypointensity on the late venous phase [n=31/35 (88.6%)]. All the lesions were hypointense on the hepatobiliary phase images., Conclusion: Focal eosinophilic liver lesions tend to be hyperintense on the arterial phase and hypointense on the late venous phase during dynamic study of Gd-EOB-DTPA-enhanced MRI. Although these findings mimic other focal hepatic lesions, poorly defined margins of the lesions and peripheral eosinophilia might help distinguish focal eosinophilic liver disease from other hepatic lesions., (Copyright © 2010 Elsevier Inc. All rights reserved.)

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.

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 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).

Objective: The aim of this study was to compare phased-array 3-T MRI and endorectal sonography in the preoperative staging of rectal cancer., Materials and Methods: During an 8-month period, 24 patients with rectal cancer underwent both 3-T MRI performed with phased-array coils and 7.5- to 10-MHz endorectal sonography in the 3 weeks before surgical resection. Three radiologists independently reviewed the MR and endorectal sonographic images. The histopathologic findings in resected specimens were used to evaluate the sensitivities and specificities of these techniques for invasion of the muscularis propria and perirectal tissue and for lymph node involvement. Receiver operating characteristic (ROC) analysis was used to compare the diagnostic accuracies of the techniques., Results: For muscularis propria invasion, the mean sensitivities of both MRI and endorectal sonography were 100%, and the mean specificities were 66.7% and 61.1%, respectively. The differences in the mean sensitivities and specificities were not statistically significant (p > 0.05 in each case). For perirectal tissue invasion, MRI and endorectal sonography had comparable sensitivities and specificities (91.1% vs 100%, 92.6% vs 81.5%; p > 0.05 in each case). They also had similar sensitivities and specificities for lymph node involvement (63.6% vs 57.6%, 92.3% vs 82.1%; p > 0.05 in each case). ROC curves for muscularis propria invasion and lymph node involvement showed no differences in diagnostic accuracy. The mean area under the ROC curve for endorectal sonography (A(Z) = 0.996) for perirectal tissue invasion, however, showed higher accuracy than that of MRI (A(Z) = 0.938, p = 0.028)., Conclusion: The sensitivity, specificity, and accuracy of 3-T MRI were similar to those of endorectal sonography for muscularis propria invasion and lymph node involvement, but for perirectal tissue invasion, 3-T MRI was less accurate than endorectal sonography.

Purpose: To verify changes in the signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of hypervascular hepatocellular carcinomas (HCCs) on ferucarbotran-enhanced dynamic T1-weighted MR imaging., Materials and Methods: Fifty-two patients with 61 hypervascular HCCs underwent ferucarbotran-enhanced dynamic MR imaging, and then hepatic resection. Hypervascular HCCs were identified when definite enhancement was noted during the arterial dominant phase of three-phase MDCT. Dynamic MR Images with T1-weighted fast multiplanar spoiled gradient-recalled echo sequence (TR200/TE4.2) were obtained before and 20 s, and 1, 3, 5, and 10 min, after bolus injection of ferucarbotran. We estimated the signal intensities of tumors and livers, and calculated the SNRs and CNRs of the tumors., Results: On ferucarbotran-enhanced dynamic MR imaging, SNR measurements showed a fluctuating pattern, namely, an increase in SNR followed by a decrease and a subsequent increase (or a decrease in SNR followed by a increase and a subsequent decrease) in 50 (82.0%) of 61 tumors, a single-peak SNR pattern (highest SNR on 20 s, 1, 3, or 5 min delayed images followed by a decrease) in seven (11.5%), and a decrease in SNR followed by an increase in four (6.6%). Maximum absolute CNRs with positive value were noted on 10 min delayed images in 41 (67.2%) tumors, and maximum absolute CNRs with negative value were observed on 20 s delayed images in 12 (19.7%) and on 1 min delayed images in eight (13.1%)., Conclusion: Despite showing various SNR and CNR changes, the majority of hypervascular HCCs demonstrated a fluctuating SNR pattern on ferucarbotran-enhanced dynamic MR imaging and a highest CNR on 10 min delayed image, which differed from the classic enhancement pattern on multiphasic CT.

Objective: To compare the diagnostic performance of a variety of magnetic resonance imaging (MRI) sequences, in order to identify the most effective ferucarbotran-enhanced sequence for the detection of multiple small hepatic VX2 carcinomas in rabbits., Methods: Fifteen rabbits with experimentally induced 135 VX2 carcinomas in the liver underwent ferucarbotran-enhanced MRI using the following nine pulse sequences: a fat-suppressed fast spin-echo (FSE) sequence with two echo times (TE) (proton density- and T2-weighted images), four different T2*-weighted fast multiplanar GRASS (gradient-recalled acquisition in the steady state) (FMPGR) with the combination of three TEs (9, 12, 15 ms, respectively) and two flip angles (20 degrees , 80 degrees, respectively), T2*-weighted fast multiplanar spoiled GRASS (FMPSPGR), T1-weighted FMPSPGR, and dynamic T1-weighted FMPSPGR. All images were reviewed by three radiologists with quantitative and qualitative analysis., Results: Tumor-to-liver contrast-to-noise ratio of the proton density-weighted FSE sequence was significantly higher than those of the others (p<0.05). The lesion conspicuities of proton density- and T2-weighted FSE and T2*-weighted FMPGR (TE/flip angle, 9/20 degrees and 12/20 degrees ) images were better and the image artifacts of T2*-weighted FMPGR (TE/flip angle, 15/20 degrees and 12/80 degrees ) and T2*-weighted FMPSPGR images were more prominent than those of the others (p<0.05). The lesion detection in T2- and proton density-weighted FSE and T2*-weighted FMPGR (TE/flip angle, 12/20 degrees ) images were superior to those of the others and for the detection of very small hepatic tumors of less than 5 mm, the sensitivities of these sequences were less than 30%., Conclusion: Ferucarbotran-enhanced T2- and proton density-weighted FSE and T2*-weighed FMPGR (TE/flip angle, 12/20 degrees ) images were found to be the most effective pulse sequences for the detection of multiple small hepatic VX2 carcinomas but these sequences were limited in the detection of very small hepatic tumors of less than 5 mm in size.

The purpose of this study was to evaluate the accuracy of 3-Tesla magnetic resonance imaging (MRI) for the preoperative staging of rectal cancer. Thirty-five patients with a primary rectal cancer who underwent preoperative 3-T MRI using a phased-array coil and had a surgical resection were enrolled in the study group. Preoperatively, three experienced radiologists independently assessed the T and N staging. A confidence level scoring system was used to determine if there was any perirectal invasion, and receiver operating characteristic (ROC) curves were generated. The interobserver agreement was estimated using kappa statistics. The overall accuracy rate of T staging for rectal cancer was 92%. The diagnostic accuracy was 97% for T1, 89% for T2 and 91% for T3, respectively. The predictive accuracy for perirectal invasion by the three observers was high (Az>0.92). The interobserver agreement for T staging was moderate to substantial. The overall sensitivity, specificity, and accuracy for the detection of mesorectal nodal metastases were 80%, 98%, and 95%, respectively. In conclusion, preoperative 3-T MRI using a phase-array coil accurately indicates the depth of tumor invasion for rectal cancer with a low variability.

Coronary MR angiography can be useful for noninvasive diagnosis of potentially life-threatening coronary artery anomalies. However, there has been no report to date on MR demonstration of acute myocardial infarction associated with right coronary artery anomaly. A 55-year-old man was admitted with chest pain. Catheter coronary angiography revealed an anomalous origin with compression in the proximal segment of right coronary artery. Breath-hold MR angiography using spiral acquisition technique showed that the right coronary artery originated from the left coronary sinus with a separate os. The proximal segment of the artery was compressed by right ventricle outflow tract during the diastolic phase of cine MR imaging. Contrast-enhanced MR imaging 5 minutes after Gd-DTPA injection showed hyperenhancement suggestive of acute myocardial infarction in the posteroinferior wall of the left ventricle.

Various ectopic lesions occur in the abdomen and pelvis and affect multiple organs including liver, gallbladder, pancreas, spleen, and organs of the genitourinary system. Ectopic organs may be present outside their normal positions, or ectopic tissues may develop while the original organ exists in its normal position. Both benign and malignant lesions can occur in ectopic organs and tissues. Owing to their unusual location, they can often be misdiagnosed as other lesions or even malignant lesions, such as metastasis or seeding. This multimodality pictorial review provides various cases of ectopic lesions in the abdomen and pelvis, which will help narrow the differential diagnosis and guide clinical decision-making. [ABSTRACT FROM AUTHOR]

The purpose of this work was to evaluate cases of benign ovarian mature teratoma (MT) with enhancing solid components on pelvic magnetic resonance imaging (MRI) and to correlate the MRI findings with the pathology reports. We retrospectively reviewed MRI findings and pathologic reports of 126 patients with pathologically confirmed ovarian MT. Enhancing solid components were observed in 24 (18.8%) of 128 benign MTs. The largest diameter ranged from 5.9 to 42.2 mm. The appearance was variable. Of 24 tumors, 19 (79.2%) had regular borders. On pathologic analysis, solid components of benign MTs were identified as glial tissue, thyroid tissue, fibrous stroma, or vessels. [ABSTRACT FROM AUTHOR]