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1.
Clin Imaging ; 35(2): 133-8, 2011.
Article in English | MEDLINE | ID: mdl-21377052

ABSTRACT

Twenty-four volunteers were examined at T1-weighted images with thin sections using gradient-based sequences with a possible short and same TR at 3.0 and 1.5 T. Pancreas-to-spleen contrast measurements and scores for visual assessments of image contrast were significantly worse at 3.0 T than at 1.5 T on both sequences. The image contrast of high-spatial-resolution T1-weighted images at 3.0 T is decreased compared to that of images with the same and possible short TR at 1.5 T.


Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity
2.
Eur J Radiol ; 73(1): 114-8, 2010 Jan.
Article in English | MEDLINE | ID: mdl-18834686

ABSTRACT

PURPOSE: The aim of this study was to evaluate image quality of 3D MR cholangiography (MRC) using high sampling efficiency technique (SPACE) at 3T compared with 1.5T. METHODS AND MATERIALS: An IRB approved prospective study was performed with 17 healthy volunteers using both 3 and 1.5T MR scanners. MRC images were obtained with free-breathing navigator-triggered 3D T2-weighted turbo spin-echo sequence with SPACE (TR, >2700ms; TE, 780ms at 3T and 801ms at 1.5T; echo-train length, 121; voxel size, 1.1mmx1.0mmx0.84mm). The common bile duct (CBD) to liver contrast-to-noise ratios (CNRs) were compared between 3 and 1.5T. A five-point scale was used to compare overall image quality and visualization of the third branches of bile duct (B2, B6, and B8). The depiction of cystic duct insertion and the highest order of bile duct visible were also compared. The results were compared using the Wilcoxon signed-ranks test. RESULTS: CNR between the CBD and liver was significantly higher at 3T than 1.5T (p=0.0006). MRC at 3T showed a significantly higher overall image quality (p=0.0215) and clearer visualization of B2 (p=0.0183) and B6 (p=0.0106) than at 1.5T. In all analyses of duct visibility, 3T showed higher scores than 1.5T. CONCLUSION: 3T MRC using SPACE offered better image quality than 1.5T. SPACE technique facilitated high-resolution 3D MRC with excellent image quality at 3T.


Subject(s)
Biliary Tract/anatomy & histology , Cholangiopancreatography, Magnetic Resonance/methods , Image Enhancement/methods , Imaging, Three-Dimensional/methods , Signal Processing, Computer-Assisted , Adult , Female , Humans , Liver , Male , Middle Aged , Sample Size
3.
Radiology ; 251(2): 388-97, 2009 May.
Article in English | MEDLINE | ID: mdl-19401572

ABSTRACT

PURPOSE: To evaluate the effectiveness of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique for superparamagnetic iron oxide (SPIO)-enhanced T2-weighted magnetic resonance (MR) imaging with respiratory compensation with the prospective acquisition correction (PACE) technique in the detection of hepatic lesions. MATERIALS AND METHODS: The institutional human research committee approved this prospective study, and all patients provided written informed consent. Eighty-one patients (mean age, 58 years) underwent hepatic 1.5-T MR imaging. Fat-saturated T2-weighted turbo spin-echo images were acquired with the PACE technique and with and without the PROPELLER method after administration of SPIO. Images were qualitatively evaluated for image artifacts, depiction of liver edge and intrahepatic vessels, overall image quality, and presence of lesions. Three radiologists independently assessed these characteristics with a five-point confidence scale. Diagnostic performance was assessed with receiver operating characteristic (ROC) curve analysis. Quantitative analysis was conducted by measuring the liver signal-to-noise ratio (SNR) and the lesion-to-liver contrast-to-noise ratio (CNR). The Wilcoxon signed rank test and two-tailed Student t test were used, and P < .05 indicated a significant difference. RESULTS: MR imaging with the PROPELLER and PACE techniques resulted in significantly improved image quality, higher sensitivity, and greater area under the ROC curve for hepatic lesion detection than did MR imaging with the PACE technique alone (P < .001). The mean liver SNR and the lesion-to-liver CNR were higher with the PROPELLER technique than without it (P < .001). CONCLUSION: T2-weighted MR imaging with the PROPELLER and PACE technique and SPIO enhancement is a promising method with which to improve the detection of hepatic lesions. (c) RSNA, 2009.


Subject(s)
Ferrosoferric Oxide , Image Enhancement/methods , Liver Neoplasms/diagnosis , Magnetic Resonance Imaging/methods , Adult , Aged , Aged, 80 and over , Contrast Media , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity
4.
AJR Am J Roentgenol ; 191(4): 1154-8, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18806158

ABSTRACT

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER [BLADE in the MR systems from Siemens Medical Solutions]) with a respiratory compensation technique for motion correction, image noise reduction, improved sharpness of liver edge, and image quality of the upper abdomen. SUBJECTS AND METHODS: Twenty healthy adult volunteers with a mean age of 28 years (age range, 23-42 years) underwent upper abdominal MRI with a 1.5-T scanner. For each subject, fat-saturated T2-weighted turbo spin-echo (TSE) sequences with respiratory compensation (prospective acquisition correction [PACE]) were performed with and without the BLADE technique. Ghosting artifact, artifacts except ghosting artifact such as respiratory motion and bowel movement, sharpness of liver edge, image noise, and overall image quality were evaluated visually by three radiologists using a 5-point scale for qualitative analysis. The Wilcoxon's signed rank test was used to determine whether a significant difference existed between images with and without BLADE. A p value less than 0.05 was considered to be statistically significant. RESULTS: In the BLADE images, image artifacts, sharpness of liver edge, image noise, and overall image quality were significantly improved (p < 0.001). CONCLUSION: With the BLADE technique, T2-weighted TSE images of the upper abdomen could provide reduced image artifacts including ghosting artifact and image noise and provide better image quality.


Subject(s)
Abdomen , Artifacts , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Adult , Female , Humans , Image Processing, Computer-Assisted , Male , Statistics, Nonparametric
5.
J Magn Reson Imaging ; 28(3): 685-90, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18777552

ABSTRACT

PURPOSE: To evaluate the image quality of high-spatial-resolution three-dimensional magnetic resonance cholangiography (MRC) with a high-sampling-efficiency technique (sampling perfection with application optimized contrasts using different flip angle evolutions [SPACE]) in comparison with a conventional constant flip angle (FA) sequence at 3T. MATERIALS AND METHODS: Eighteen volunteers were examined on a 3T MR unit using MRC imaging performed with three different free-breathing three-dimensional T2-weighted turbo spin-echo (TSE) sequences: 1) SPACE (spatial resolution, 1.1x1.0x0.84 mm), 2) constant FA (1.1x1.0x0.84 mm), and 3) SPACE at a higher resolution (SPACE HR; 1.0x0.9x0.644 mm). A five-point scale was used to compare overall image quality and visualization of the third branches of the bile duct (B2, B6, and B8). Depictions of cystic duct insertion and the highest order of bile duct visible were also compared. RESULTS: MRC with SPACE and SPACE HR sequences produced significantly better overall image quality than the constant FA sequence. In all analyses of duct visibility, SPACE and SPACE HR sequences showed higher scores than the constant FA sequence. CONCLUSION: High-resolution three-dimensional MRC with SPACE at 3T allows high-quality imaging of the biliary tract, and has the ability to depict nondilated intrahepatic bile ducts (IHBD) in healthy volunteers.


Subject(s)
Algorithms , Biliary Tract/anatomy & histology , Cholangiopancreatography, Magnetic Resonance/methods , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Signal Processing, Computer-Assisted , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sample Size , Sensitivity and Specificity
6.
J Magn Reson Imaging ; 28(4): 957-62, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18821630

ABSTRACT

PURPOSE: To evaluate motion correction effect and image quality in the upper abdomen with the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) (BLADE) and parallel imaging acquisition technique. MATERIALS AND METHODS: A total of 50 consecutive patients underwent abdominal MR imaging. Fat-saturated T2-weighted turbo spin-echo sequences were obtained by respiratory triggering. The subjects were examined with three different conditions of echo train length (ETL), blade width, and percent k-space coverage in the same scanning time: 19/30/100%, 30/30/100%, and 30/52/175%, which were designated as L/C(1), L/C(2), and L/C(3), respectively. The parallel imaging acquisition technique was used to either reduce ETL from 30 to 19 in L/C(1) or increase k-space coverage from 100% to 175% in L/C(3) compared with L/C(2). Motion and streak artifacts, and overall image quality were evaluated visually by two radiologists, independently. RESULTS: Motion and streak artifacts were mostly reduced in L/C(3) condition. The L/C(3) image also gave the best overall image quality compared with other conditions (P < 0.001). The inter-rater reliability for each evaluation agreed well. CONCLUSION: In upper abdominal BLADE MRI, it was possible to reduce image artifacts and obtain better image quality by increasing the k-space coverage with parallel imaging in the same scanning time.


Subject(s)
Abdomen/pathology , Image Enhancement/methods , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Adult , Aged , Analysis of Variance , Artifacts , Female , Humans , Male , Middle Aged , Quality Control , Statistics, Nonparametric
7.
Intervirology ; 51 Suppl 1: 46-51, 2008.
Article in English | MEDLINE | ID: mdl-18544948

ABSTRACT

OBJECTIVE: To compare 8-detector row helical computed tomography (CT) findings with histopathology in patients with hepatocellular carcinoma (HCC) who had undergone living-donor liver transplantation (LDLT). MATERIALS AND METHODS: This institutional review board-approved prospective study was performed between February 12, 2003 and November 12, 2004; of the 78 candidates for LDLT due to HCC who underwent preoperative multidetector CT (MDCT), 48 transplant recipients met our criteria and in 41 of them, HCCs were diagnosed with <15 lesions on MDCT; these patients represented the study population. Results of preoperative CT were correlated with histopathological results after 5-mm sagittal slicing of the explanted liver. Following the injection of contrast medium (2 ml/kg body weight of 300 mg I/ml), triple-phase contrast-enhanced images were obtained. CT was performed using the following parameters: detector row configuration, 8 x 1 mm, reconstruction interval, 1 mm, 200 mA s and 120 kVp. Image analysis was performed in consensus by three abdominal radiologists using 1-mm-thick slices with 0.5-mm overlap with paging as well as multiplanar reformatting (MPR; i.e. axial, coronal and sagittal images). RESULTS: A total of 134 HCCs were identified by pathological examination. The mean lesion size was 21 mm. Sensitivity, positive predictive value and accuracy for HCC detection were 87, 96 and 84% for all lesions, respectively, and 99, 100 and 97% for lesions >1 cm, respectively, but only 46, 76 and 41% for tumors <1 cm, respectively (n = 28). There were 12 false-negative lesions but only 5 false-positive findings. CONCLUSION: MDCT combined with the paging method and MPR images is very effective in the detection of HCCs >1 cm in diameter with a very low false-positive rate.


Subject(s)
Carcinoma, Hepatocellular/diagnosis , Liver Neoplasms/diagnosis , Liver Transplantation , Liver/diagnostic imaging , Tomography, X-Ray Computed/methods , Carcinoma, Hepatocellular/therapy , Contrast Media , Diagnostic Imaging , False Positive Reactions , Female , Humans , Liver/pathology , Living Donors , Male , Middle Aged , Prospective Studies , Sensitivity and Specificity , Ultrasonography
8.
AJR Am J Roentgenol ; 190(5): 1314-7, 2008 May.
Article in English | MEDLINE | ID: mdl-18430849

ABSTRACT

OBJECTIVE: The purpose of this study was to determine the efficacy of CT laparoscopy in the detection of superficial metastasis of the liver surface. SUBJECTS AND METHODS: From April 1, 2007, to July 1, 2007, a total of 34 consecutively registered patients (19 men, 15 women; median age, 55 years) with various intraabdominal malignant tumors underwent preoperative CT and composed the study population. All patients underwent superparamagnetic iron oxide-enhanced MRI and portal phase contrast-enhanced 64-MDCT, including CT laparoscopy. CT laparoscopy is a form of volume-rendering 3D imaging of the liver that depicts the liver surface in detail. RESULTS: Among 23 patients who underwent surgery for management of a primary tumor, four patients had seven superficial metastatic lesions of the liver surface. None of these lesions had been detected with preoperative axial CT or superparamagnetic iron oxide-enhanced MRI. In contrast, CT laparoscopy revealed four of seven lesions in four patients. On a lesion-by-lesion basis, the sensitivity was 57%, the positive predictive value was 100%, and the accuracy was 57%. CONCLUSION: Our initial experience proves that CT laparoscopy is a promising method for detecting small superficial metastatic lesions of the liver surface. The findings can influence decisions regarding tumor resectability.


Subject(s)
Digestive System Neoplasms/pathology , Laparoscopy , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/secondary , Tomography, X-Ray Computed , Aged , Contrast Media , Female , Follow-Up Studies , Humans , Iopamidol/analogs & derivatives , Liver Neoplasms/surgery , Magnetic Resonance Imaging , Male , Middle Aged , Predictive Value of Tests , Prospective Studies
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