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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.

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: 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: To describe the clinical presentation and computed tomographic (CT) features of ascending retrocecal appendicitis., Methods: During the past 8 years, 1670 patients with surgically proven appendicitis were identified by a retrospective investigation. Thirty-three patients who underwent contrast-enhanced abdominal CT before surgery and had ascending retrocecal appendicitis at surgery were included in the patient cohort. The clinical and CT findings of these 33 patients were analyzed., Results: Patients presented with right lower abdominal pain (49%, 16/33), right flank pain (24%, 8/33), right upper abdominal pain (18%, 6/33), and periumbilical pain (15%, 5/33). Inflamed ascending retrocecal appendices were visualized completely in 70% (23/33), partially in 21% (7 of 33), and not detected in the remaining 9% (3/33). Periappendiceal inflammatory changes were most commonly observed in the retrocolic space in 88% (29/33), followed by paracolic gutter (30%, 10/33), pararenal space (27%, 9/33), mesentery (24%, 8/33), perirenal space (18%, 6/33), and subhepatic space (3%, 1/33). Inflammatory thickening of Gerota fascia (70%, 23/33) and the lateroconal fascia (64%, 21/33) was observed as well. Perforation of the appendix with the formation of an abscess was present in 49% (16/33). The abscesses were most commonly located in the retrocolic space (88%, 14/16). Diffuse wall thickenings of the cecum (67%, 22/33) and the ascending colon (64%, 21/33) were often observed also. Appendicoliths were found in 33% (11/33)., Conclusions: More than half of patients with ascending retrocecal appendicitis presented with atypical clinical presentation. At CT, ascending retrocecal appendicitis was associated with a high incidence of retroperitoneal inflammatory changes and appendiceal perforation.

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.