[Show abstract][Hide abstract] ABSTRACT: Purpose: To investigate the correlations between parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and prognostic factors in rectal cancer. Materials and Methods: We studied 29 patients with rectal cancer who underwent gadolinium contrast-enhanced, T1-weighted DCE-MRI with a three Tesla scanner prior to surgery. Signal intensity on DCE-MRI was independently measured by two observers to examine reproducibility. A time-signal intensity curve was generated, from which four semiquantitative parameters were calculated: steepest slope (SLP), time to peak (Tp), relative enhancement during a rapid rise (Erise), and maximal enhancement (Emax). Morphologic prognostic factors including T stage, N stage, and histologic grade were identified. Tumor angiogenesis was evaluated in terms of microvessel count (MVC) and microvessel area (MVA) by morphometric study. As molecular factors, the mutation status of the K-ras oncogene and microsatellite instability were assessed. DCE-MRI parameters were correlated with each prognostic factor using bivariate correlation analysis. A p-value of <0.05 was considered significant. Results: Erise was significantly correlated with N stage (r=-0.387 and -0.393, respectively, for two independent data), and Tp was significantly correlated with histologic grade (r=0.466 and 0.489, respectively). MVA was significantly correlated with SLP (r= -0.532 and -0.535, respectively) and Erise (r=-0.511 and -0.446, respectively). MVC was significantly correlated with Emax (r=-0.435 and -0.386, respectively). No significant correlations were found between DCE-MRI parameters and T stage, K-ras mutation, or microsatellite instability. Conclusion: DCE-MRI may provide useful prognostic information in terms of histologic differentiation and angiogenesis in rectal cancer.
Yonsei medical journal 01/2013; 54(1):123-30. · 0.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To define diagnostic criteria for differentiating malignant ampullary carcinoma from benign ampullary obstruction on MR imaging.
Nineteen patients with ampullary carcinoma and 22 patients with benign ampullary obstruction were enrolled. At the first session, two radiologists independently evaluated specific imaging findings, and then reached consensus decisions. At the second session, another two radiologists, who were informed about useful differentiation criteria based on the results from the first session, reviewed images and determined the causes of ampullary obstruction. Sensitivity and specificity were calculated for each interpretation session, and the Cohen κ statistic was used to evaluate interobserver agreement.
Findings of the presence of an ampullary mass (P<0.001), papillary bulging (P<0.001), irregular (P=0.021) and asymmetric (P<0.001) common bile duct (CBD) narrowing, and proportional biliary dilatation (P<0.001) were more commonly seen in patients with an ampullary carcinoma. The sensitivity and specificity of the first session were 84.2% and 86.4% after consensus. The sensitivity increased to 100% for both the readers at the second session, while the specificity decreased to 63.6% and 59.1%, respectively.
Identification of an ampullary mass, papillary bulging, irregular and asymmetric narrowing of the CBD, or proportional biliary dilatation may improve the diagnosis of ampullary carcinoma in patients with ampullary obstruction.
European journal of radiology 11/2011; 80(2):198-203. · 2.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To compare the use of heavily T2-weighted images obtained before and after administration of gadoxetic acid in differentiating hemangiomas from malignant solid hepatic lesions.
Heavily T2-weighted images (TE=150 msec) were obtained for 70 patients (42 men and 28 women) with 74 focal hepatic lesions (25 hepatocellular carcinomas [HCC], 22 metastases, and 27 hemangiomas) ≤3 cm in diameter before and after gadoxetic acid-enhanced dynamic magnetic resonance imaging (MRI). Quantitative analysis was performed using receiver operating characteristic (ROC) curves with lesion-to-liver signal intensity difference-to-noise ratio (SDNR) on precontrast and postcontrast images. Qualitative analysis was also performed by two blinded reviewers.
The SDNR of the solid lesions was significantly higher on the postcontrast (1.66 ± 1.18) than on the precontrast (1.38 ± 1.07) images (P=0.0012), while the SDNR of hemangiomas was comparable for pre- and postcontrast images (P=0.8164). The best SDNR cutoff values for distinguishing solid lesions from hemangiomas were ≤1.85 (Az=0.948) for precontrast and ≤2.58 (Az=0.901) for postcontrast images (P=0.057). Reader performances for distinguishing hemangiomas from solid lesions were comparable between the precontrast (Az=0.975 and 0.970 for readers 1 and 2) and postcontrast (Az=0.977 and 0.972) images (P=0.899 and 0.946).
Heavily T2-weighted images obtained after administration of gadoxetic acid have a diagnostic capability comparable to precontrast images for differentiating between small hemangiomas and malignant solid lesions of the liver.
Journal of Magnetic Resonance Imaging 05/2011; 34(2):310-7. · 2.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To compare the image quality of two variants of a three-dimensional (3D) gradient echo sequence (GRE) for hepatic MRI.
Thirty-nine patients underwent hepatic MRI on a 3.0 Tesla (T) magnet (Intera Achieva; Philips Medical Systems). The clinical protocol included two variants of a 3D GRE with fat suppression: (i) a "centric" approach, with elliptical centric k-space ordering and (ii) an "enhanced" approach using linear sampling and partial Fourier in both the slice and phase encoding direction. "Centric" and "Enhanced" 3D GRE images were obtained both precontrast (n = 32) and after gadoxetic acid injection (n = 39). Two reviewers jointly reviewed MR images for anatomic sharpness, overall contrast, homogeneity, and absence of artifacts. The liver-to-lesion signal difference ratio (SDR) was measured. Paired sample Wilcoxon test and paired t-tests were used.
Enhanced 3D GRE images performed better than centric 3D GRE images with respect to anatomic sharpness (P = 0.0156), overall contrast (P = 0.0195), homogeneity (P < 0.0001), and absence of artifacts (P = 0.0003) on precontrast images. For postcontrast MRI, enhanced 3D GRE images showed better quality in terms of overall contrast (P = 0.0195), homogeneity (P < 0.0001), and absence of artifacts (P = 0.009). Liver-to-lesion SDR on enhanced 3D GRE images (0.48 ± 0.13) was significantly higher than that of conventional 3D GRE images (0.40 ± 0.19, P = 0.0004) on postcontrast images, but not on precontrast images.
The enhanced 3D GRE sequence available on our scanner provided better hepatic image quality than the centric variant, without compromising lesion contrast.
Journal of Magnetic Resonance Imaging 01/2011; 33(1):160-6. · 2.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To assess the utility of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in evaluating pancreatic intraductal papillary mucinous neoplasm (IPMN).
We included 31 patients with pancreatic IPMN who underwent F-18 FDG PET/CT and multidetector CT (MDCT). Each pancreatic lesion was classified as benign or malignant. On PET, the maximal standardized uptake value was measured in each pancreatic lesion.
PET/CT was superior to MDCT in diagnosing malignant IPMN. All 22 concordant results gave accurate diagnoses. Of 9 discordant results, MDCT misdiagnosed 7 IPMNs, whereas PET/CT misinterpreted 2. Malignant IPMNs showed significantly higher maximal standardized uptake values (mean ± standard deviation, 6.7 ± 3.6) than benign IPMNs (mean ± standard deviation, 2.1 ± 1.0) (P < 0.001).
F-18 FDG PET/CT outperformed MDCT in detecting malignant IPMN.
Clinical nuclear medicine 10/2010; 35(10):776-9. · 3.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To compare the image quality and diagnostic performance with T2-weighted magnetic resonance (MR) cholangiopancreatographic images obtained before and after dynamic MR imaging performed with gadoxetic acid.
This retrospective study was approved by the institutional review board, and informed consent was waived. Fifty-six patients suspected of having pancreatic or biliary disease underwent two-dimensional (2D) single-section and three-dimensional (3D) multisection MR cholangiopancreatography before and after dynamic imaging with gadoxetic acid. One radiologist measured the mean signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the common bile duct on precontrast and postcontrast images. Two radiologists independently reviewed the 2D and 3D MR cholangiopancreatographic images in random order. The depiction of each segment of the pancreaticobiliary duct, the presence of artifacts, background suppression, and overall image quality were assessed according to a four-point scale. Paired t, McNemar, and Wilcoxon signed rank tests were performed with a power analysis. Interobserver agreement was assessed by using the kappa statistic.
Mean SNRs at precontrast MR imaging (2D, 50.8 +/- 45.1 [standard deviation]; 3D, 54.7 +/- 25.5) were similar to those at postcontrast MR imaging (2D, 48.5 +/- 45.7; 3D, 51.5 +/- 21.6). Mean CNRs were also similar between precontrast and postcontrast MR imaging (2D, 45.5 +/- 43.0 vs 44.2 +/- 45.2; 3D, 51.4 +/- 24.3 vs 48.7 +/- 21.0). Depiction scores for each segment of the pancreaticobiliary duct were also similar between 2D and 3D precontrast and postcontrast images. Both radiologists found that scores for background suppression were improved on postcontrast 2D MR images (3.79 and 3.84) compared with precontrast images (3.25 and 3.64). One of the two radiologists found that scores for artifacts (precontrast, 1.23; postcontrast, 1.09) and for overall image quality (precontrast, 3.54; postcontrast, 3.71) were improved at 2D postcontrast MR cholangiopancreatography.
Both 2D and 3D MR cholangiopancreatography can be effectively performed immediately after gadoxetic acid-enhanced dynamic MR imaging in patients suspected of having biliary or pancreatic disease.
[Show abstract][Hide abstract] ABSTRACT: To determine the added value of hepatobiliary phase images in gadoxetic acid-enhanced magnetic resonance (MR) imaging in the evaluation of hepatocellular carcinoma (HCC).
Institutional review board approved this retrospective study and waived the informed consent. Fifty-nine patients with 84 HCCs underwent gadoxetic acid-enhanced MR examinations that included 20-minute delayed hepatobiliary phase imaging. MR imaging was performed with a 1.5-T system in 19 patients and a 3.0-T system in 40 patients. A total of 113 hepatic nodules were documented for analysis. Three radiologists independently reviewed two sets of MR images: set 1, unenhanced (T1- and T2-weighted) and gadoxetic acid-enhanced dynamic images; set 2, hepatobiliary phase images and unenhanced and gadoxetic acid-enhanced dynamic images. For each observer, the diagnostic accuracy was compared by using the area under the alternative free-response receiver operating characteristic curve (A(z)). Sensitivity and specificity were also calculated and compared between the two sets.
For all observers, A(z) values were higher with the addition of the hepatobiliary phase. The observer who had the least experience in abdominal imaging (2 years) demonstrated significant improvement in A(z), from 0.895 in set 1 to 0.951 in set 2 (P = .049). Sensitivity increased with the addition of hepatobiliary phase images but did not reach statistical significance. Nine HCCs (10.7%) in six patients (10.1%) were seen only on hepatobiliary phase images.
Hepatobiliary phase images obtained after gadoxetic acid-enhanced dynamic MR imaging may improve diagnosis of HCC and assist in surgical planning.
[Show abstract][Hide abstract] ABSTRACT: To compare two different injection rates for gadoxetic acid-enhanced hepatic arterial phase images on hepatic dynamic MRI.
Hepatic arterial phase images were obtained after an intravenous bolus injection of gadoxetic acid at a rate of 1 mL/second in 62 patients and 2 mL/second in 64 patients on a 3 Tesla MR scanner using a test-bolus injection method. The signal-to-noise ratios (SNR) of the liver, portal vein, hepatic vein, aorta, spleen and pancreas were measured. The contrast-to-noise ratio (CNR) of hypervascular hepatic tumors was calculated. Two radiologists independently scored items to evaluate image quality of hepatic arterial phase and detected hypervascular hepatocellular carcinoma (HCC).
The SNR of the aorta on the arterial phase images was significantly higher in the 1 mL/second group (235.43 +/- 82.59) than in the 2 mL/second group (190.94 +/- 96.90, P < 0.05). The SNRs of the liver, spleen and pancreas, the CNRs of hypervascular hepatic tumors, the detection rate of hypervascular HCC and subjective ratings for the optimal arterial enhancement were comparable between the two groups.
Injection rates of 2 mL/second and 1 mL/second provided comparable image qualities on arterial phase images of hepatic dynamic MRI using gadoxetic acid.
Journal of Magnetic Resonance Imaging 02/2010; 31(2):365-72. · 2.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We examined 20 prediagnostic CTs from 16 patients for whom the diagnosis of pancreatic cancer was delayed until full diagnostic
CT was performed. Three radiologists independently reviewed the prediagnostic CTs along with 50 CTs of control subjects, including
patients without pancreatic disease (n = 38) or with chronic pancreatitis without calcification visible on CT (n = 12). The reviewers recorded the presence of biliary or pancreatic ductal dilation, interruption of the pancreatic duct,
distal parenchymal atrophy, contour abnormality and focal hypoattenuation. Frequency, sensitivity and specificity of the significant
findings were calculated. Logistic regression analysis was performed. Findings indicative of pancreatic cancer were seen on
85% (17/20) of the prediagnostic CTs. Patients with pancreatic cancer were significantly (p < 0.05) more likely to show focal hypoattenuation, pancreatic duct dilation, interruption of the pancreatic duct, and distal
parenchymal atrophy, with sensitivities and specificities of 75%/84%, 50%/78%, 45%/82% and 45%/96%, respectively. Focal hypoattenuation
and distal parenchymal atrophy were the independent predictors of pancreatic cancer with odds ratios of 20.92 and 11.22, respectively.
In conclusion, focal hypoattenuation and pancreatic duct dilation with or without interruption, especially when accompanied
by distal parenchymal atrophy, were the most useful findings for avoiding delayed diagnosis of pancreatic cancer.
European Radiology 10/2009; 19(10):2448-2455. · 4.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to investigate differential imaging features between benign and malignant solid pseudopapillary neoplasms (SPN) of the pancreas on computed tomographic and magnetic resonance imagings.
Between January 2001 and January 2007, we identified 30 patients with confirmed SPN by surgery. The computed tomographic and magnetic resonance images were reviewed by 3 radiologists in consensus. Each tumor was analyzed for the following categories: location of tumor, tumor margin, proportion of solid component, morphology of capsule, growth pattern, calcification, and presence of upstream pancreatic ductal dilatation.
Benign SPN usually had oval/round or smoothly lobulated margins, and malignant SPN more commonly had focal lobulated margins (P = 0.027). Presence of complete encapsulation was more frequently seen in benign SPN, whereas focal discontinuity of capsule was more commonly seen in malignant SPN (P = 0.005). There was no statistical difference between benign and malignant tumors in other imaging findings.
A focal lobulated margin and a focal discontinuity of the capsule may suggest malignant SPN, whereas a round or smoothly lobulated margin and a complete encapsulation were more commonly seen in benign SPN.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the effect of neoadjuvant combined chemotherapy and radiation therapy (CCRT) on preoperative accuracy of multidetector computed tomography (CT) for resectability and tumor staging in patients with pancreatic head cancer.
This retrospective study received institutional review board approval and was exempted from informed consent requirements. From May 2002 to March 2007, 38 patients with pancreatic head adenocarcinoma underwent multidetector CT before surgery. Of these, 12 patients received neoadjuvant CCRT. Imaging findings were evaluated for tumor resectability and tumor staging. Surgical and pathologic results were used as the reference standard. The accuracy of resectability and individual components of each T category were compared between the patients with neoadjuvant CCRT and without it by using the chi(2) test or Fisher exact test. A P of less than .05 was considered as significant.
The accuracy in determining resectability was 83% (10 of 12) in patients who had received neoadjuvant CCRT and 81% (21 of 26) in patients who had not, without significant difference (P > .05). Of 32 patients who underwent pancreaticoduodenectomy, histopathologic tumor staging was reported for T1 (n = 2), T2 (n = 1), and T3 (n = 9) lesions in patents with neoadjuvant CCRT (n = 12), and for T3 in all patients without neoadjuvant CCRT (n = 20). T-staging accuracy was 67% (eight of 12) with neoadjuvant CCRT and 95% (19 of 20) without it, with a significant difference (P = .0185).
Neoadjuvant CCRT reduces the accuracy of tumor restaging after treatment of pancreatic head cancer, but this effect is not so great as to affect the determination of resectability.
[Show abstract][Hide abstract] ABSTRACT: Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a unique disease entity that is characterized by predominant intraductal growth of mucinous cells, copious mucin production, and subsequent cystic dilatation of pancreatic ducts. IPMN shows a spectrum of histologic and imaging findings and possesses as the potential for malignant transformation arising from adenoma to invasive carcinoma. It is important to determine the type, extent of duct involvement, and presence of malignant transformation, and to assess tumor grading prior to surgical resection. Thus, it would be helpful for physicians managing patients with IPMN of the pancreas to have a guideline for the diagnosis and treatment of IPMN. In this review, a role of radiological evaluation for diagnosis and preoperative assessment is described as well as presentation of the guideline for patient management.
The Korean journal of gastroenterology = Taehan Sohwagi Hakhoe chi 11/2008; 52(4):207-13.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the feasibility of single breath-hold, multiarterial MRI of the liver using the THRIVE-CENTRA-keyhole technique.
Twenty-eight patients with 63 focal hepatic lesions underwent liver MR examinations that included the three-dimensional THRIVE-CENTRA-keyhole sequence. Three or six phases were obtained for arterial phase scanning during a single breath-hold. Central k-space data were collected for each phase but the remaining peripheral k-space data were collected only once. The enhancement pattern of each hepatic lesion was analyzed according to the specific diagnosis.
Hepatocellular carcinomas (n = 24) enhancement patterns included: rim enhancing (n = 9), homogeneous (n = 7), nodule-in-nodule (n = 5), or heterogeneous (n = 3). A late peritumoral rim was observed in four (17%) of the hepatocellular carcinomas. Most metastases (17 of 18; 94%) demonstrated peripheral rim enhancement. The progressive centripetal enhancement of hemangiomas (n = 6) was clearly depicted. Focal nodular hyperplasia (n = 4) showed early homogeneous enhancement and one lesion demonstrated a central scar.
The THRIVE-CENTRA-keyhole technique can be used to acquire single breath-hold, multiarterial images depicting improved enhancement characteristics of focal hepatic lesions. This technique will allow accurate timing of arterial scanning with 3D acquisition and high temporal resolution.
Journal of Magnetic Resonance Imaging 09/2008; 28(2):396-402. · 2.57 Impact Factor