[Synchronous Lung Metastasis and Hilar Lymph Node Metastasis from Rectal Cancer-A Case Report].

A 64-year-old male was referred to our hospital with both advanced rectal cancer and lung tumor with swollen lymph nodes in the lung hilum. The patient underwent laparoscopic low anterior resection followed by systematic lobectomy of the lung 2 months later. Postoperative pathological examination revealed a diagnosis of metastatic lung tumor and metastasis in the lung hilum. However, hilar lymph node metastasis is considered a poor prognostic factor for lung metastasis. Herein, we report a case of synchronous lung metastasis and hilar lymph node metastasis from colorectal cancer that achieved 20 months of recurrence free survival with surgical therapy alone.

[A Case Report of Neuroendocrine Carcinoma in the Gall Bladder Showing Recurrence Shortly after Surgery].

A55 -year-old woman with a 10×8mm protuberant gallbladder lesion visited our hospital. To determine possible malignancy, she underwent laparoscopic excision biopsy of the gallbladder, and pathological findings revealed an endocrine carcinoma in the gallbladder. Surgery involved extrahepatic bile duct resection, gallbladder bed resection, and hepatic portal lymph node resection. Recurrence in the peritoneal lymph node was observed in the early postoperative period. Chemotherapy was initiated with cisplatin and irinotecan, and continues 18 months post-operatively. Neuroendocrine carcinoma of the gallbladder is rare and is known to have a poor prognosis, with few confirmed treatments reported for this disease due to its rarity. Therefore, we report this case along with a review of the literature.

[Multicenter trial for optimization of bolus tracking settings and contrast material injection protocol in arterial dominant phase of dynamic computed tomography for diagnosis of hepatocellular carcinoma].

Alongside current improvements in the performance of computer tomography (CT) systems, there has been an increase in the use of bolus tracking (BT) to acquire arterial dominant phase images for dynamic CT at optimal timing for characterization of liver focal lesions. However, optimal BT settings have not been established. In the present study, methods of contrast enhancement and BT setting values were evaluated using a multicenter post-marketing surveillance study on contrast media used in patients with chronic hepatitis and/or cirrhosis who had undergone liver dynamic CT for diagnosis of hepatocellular carcinoma, conducted by Daiichi Sankyo Co., Ltd. The results suggested the contrast injection method to be clinically useful if the amount of iodine per kilogram of body weight is set at 600 mg/kg and the injection duration at 30 s. To achieve a good arterial dominant scan under conditions where the injection duration is fixed at 30 s or the average injection duration is 34 s using the fixed injection rate method, the scan delay time should ideally to be set to longer than 13 s. If using the BT method, we recommend that the BT settings should be revalidated in reference to our results.

Cross-validation of MR elastography and ultrasound transient elastography in liver stiffness measurement: discrepancy in the results of cirrhotic liver.

PURPOSE: To evaluate individual differences in liver stiffness measurement using both MR elastography (MRE) and ultrasound transient elastography (UTE) in patients with chronic liver disease. MATERIALS AND METHODS: This study included 80 patients with chronic liver disease who underwent both UTE and MRE. MRE and UTE were performed using a pneumatic driver (60 Hz) and an ultrasound probe with a vibrator (50 Hz), respectively. Liver stiffness data measured using the two techniques (µ(UTE) and µ(MRE) ) were compared with respect to shear modulus. The patients were subdivided into four quartiles on the basis of average of the µ(UTE) and µ(MRE) values for each patient. RESULTS: The analysis of the 4 quartile groups revealed that µ(UTE) was significantly higher than µ(MRE) in the two most stiff liver groups: µ(UTE) versus µ(MRE) , 7.5 (1.2) versus 6.0 (0.72) kPa for the group with [µ(UTE) + µ(MRE) ]/2 of 5.6-8.0 kPa; 15.1(4.2) versus 6.7 (1.4) kPa for the group with >8.0 kPa. However, in the least stiff liver group (i.e., the group with [µ(UTE) + µ(MRE) ]/2 < 3.2 kPa), µ(UTE) was significantly lower than µ(MRE) . CONCLUSION: The shear modulus measured by UTE and MRE are not equivalent, especially in patients with stiff livers.

Mass-forming autoimmune pancreatitis and pancreatic carcinoma: differential diagnosis on the basis of computed tomography and magnetic resonance cholangiopancreatography, and diffusion-weighted imaging findings.

PURPOSE: To differentiate mass-forming autoimmune pancreatitis (AIP) from pancreatic carcinoma by means of analysis of both computed tomography (CT) and magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS: Ten patients with mass-forming AIP diagnosed by revised clinical criteria of Japan Pancreas Society and 70 patients with pathologically proven pancreatic carcinoma were enrolled in this retrospective study. Two radiologists independently evaluated the CT and MR imaging findings. The sensitivity, specificity, and odds ratio of significant imaging findings and combinations of findings were calculated. RESULTS: Seven findings were more frequently observed in AIP patients: (i) early homogeneous good enhancement, (ii) delayed homogeneous good enhancement, (iii) hypoattenuating capsule-like rim, (iv) absence of distal pancreatic atrophy, (v5) duct penetrating sign, (vi) main pancreatic duct (MPD) upstream dilatation ≤ 4 mm, and (vii) an apparent diffusion coefficient (ADC) ≤ 0.88 × 10(-3) mm(2) /s. When the findings of delayed homogeneous enhancement and ADC ≤ 0.88 × 10(-3) mm(2) /s were both used in diagnosis of mass-forming AIP, a sensitivity of 100% and a specificity of 100% were achieved. When 4 of any of the 7 findings were used in the diagnosis of AIP, a sensitivity of 100% and a specificity of 98% were achieved. CONCLUSION: Analysis of a combination of CT and MR imaging findings allows for highly accurate differentiation between mass-forming AIP and pancreatic carcinoma.

Detection of pancreatic carcinoma and liver metastases with gadoxetic acid-enhanced MR imaging: comparison with contrast-enhanced multi-detector row CT.

PURPOSE: To intraindividually compare gadoxetic acid-enhanced magnetic resonance (MR) imaging with contrast material-enhanced multi-detector row computed tomography (CT) in detection of pancreatic carcinoma and liver metastases. MATERIALS AND METHODS: The ethics committee approved this retrospective study with waiver of informed consent. This study included 100 patients (53 men, 47 women; mean age, 67.8 years) consisting of 54 patients with pathologically confirmed pancreatic carcinoma (mean size, 33 mm) and 46 without a pancreatic lesion. Sixty-two liver metastases (mean size, 10 mm) in 15 patients with pancreatic carcinoma were diagnosed at pathologic examination or multimodality assessment. Three readers blinded to the final diagnosis interpreted all MR (precontrast T1- and T2-weighted and gadoxetic acid-enhanced dynamic and hepatocyte phase MR images) and tetraphasic dynamic contrast-enhanced CT images and graded the presence (or absence) of pancreatic carcinoma and liver metastasis on patient-by-patient and lesion-by-lesion bases. Receiver operating characteristic analysis, McNemar test, and Fisher test were performed to compare the diagnostic performance of CT and MR imaging. RESULTS: No significant differences were observed between CT and MR images in depiction of pancreatic carcinoma. However, MR imaging had greater sensitivity in depicting liver metastasis than did CT for two of the three readers in the MR imaging-versus-CT analysis (85% vs 69%, P = .046) and for all three readers in the lesion-by-lesion analysis (92%-94% vs 74%-76%, P = .030-.044). CONCLUSION: Gadoxetic acid-enhanced MR imaging was equivalent to dynamic contrast-enhanced CT in depicting pancreatic carcinoma and had better sensitivity for depicting liver metastases, suggesting the usefulness of gadoxetic acid-enhanced MR imaging for evaluation of patients with pancreatic carcinoma.

Imaging study of early hepatocellular carcinoma: usefulness of gadoxetic acid-enhanced MR imaging.

PURPOSE: To describe imaging findings of early hepatocellular carcinoma (HCC) at gadoxetic acid-enhanced magnetic resonance (MR) imaging, dynamic contrast material-enhanced computed tomography (CT), CT during arterial portography (CTAP), and CT during hepatic arteriography (CTHA) and to compare the diagnostic performance of each modality for small (≤ 2 cm) HCC. MATERIALS AND METHODS: The institute ethics committee deemed study approval unnecessary. One hundred eight resected small lesions in 64 patients were diagnosed as a dysplastic nodule (DN) (n = 12), progressed HCC (n = 66), or early HCC (n = 30). All but two patients underwent all imaging examinations. The imaging characteristics of the lesions with each modality were determined. To evaluate the diagnostic performance of the modalities, two radiologists graded the presence of HCC with use of a five-point confidence scale. The area under the receiver operating characteristic curve (A(z)), sensitivity, and specificity of each modality were compared. RESULTS: The imaging features that are statistically significant for differentiating an early HCC from a DN include fat-containing lesions at dual-echo T1-weighted MR imaging (seen in 16 of the 30 early HCCs and none of the DNs), low attenuation at unenhanced CT (seen in 13 of the 30 early HCCs and none of the DNs), low attenuation at CTAP (seen in 11 of the 30 early HCCs and none of the DNs), and low signal intensity at hepatocyte phase gadoxetic acid-enhanced MR imaging (seen in 29 of the 30 early HCCs and none of the DNs). The diagnostic performance of gadoxetic acid-enhanced MR imaging (A(z), 0.98 and 0.99) was significantly greater than that of contrast-enhanced CT (A(z), 0.87) and CTHA-CTAP (A(z), 0.85 and 0.86) owing to its significantly higher sensitivity (P < .001). CONCLUSION: Gadoxetic acid-enhanced MR imaging is the most useful imaging technique for evaluating small HCC, including early HCC.

Outcome of hypovascular hepatic nodules revealing no gadoxetic acid uptake in patients with chronic liver disease.

PURPOSE: To elucidate the natural history of hypovascular nodules that appear hypointense on hepatocyte-phase gadoxetic acid-enhanced MR images by focusing on hypervascularization over time. MATERIALS AND METHODS: In this study, 135 hypovascular nodules revealing no gadoxetic acid uptake in 53 patients were examined. All nodules were retrospectively examined using serial follow-up computed tomography (CT) and MRI examinations until hypervascularity was observed on arterial-phase dynamic CT or gadoxetic acid-enhanced MR images, or on CT during hepatic arteriography. Logistic regression analysis was used to investigate the association between hypervascularization and MR findings including a presence of fat assessed by a signal drop on opposed-phase T1-weighted images. RESULTS: Of the 135 nodules, 16 underwent hypervascularization. The size of the nodules and the presence of fat in the nodules were independent indicators of hypervascularization. The 1-year cumulative risk of hypervascularization was 15.6%. This risk was significantly increased in the case of nodules >10 mm (37.6%, P < 0.01) and fat-containing nodules (26.5%, P < 0.01). CONCLUSION: Hypovascular nodules that appear hypointense on hepatocyte-phase gadoxetic acid-enhanced MR images may progress to conventional hypervascular hepatocellular carcinoma. Nodules more than 10 mm in diameter and containing fat are at high risk for developing hypervascularization.

Diagnosis of colorectal hepatic metastases: comparison of contrast-enhanced CT, contrast-enhanced US, superparamagnetic iron oxide-enhanced MRI, and gadoxetic acid-enhanced MRI.

PURPOSE: To compare the diagnostic accuracy of contrast-enhanced computed tomography (CE-CT), contrast-enhanced ultrasonography (CE-US), superparamagnetic iron oxide-enhanced magnetic resonance imaging (SPIO-MRI), and gadoxetic acid-enhanced MRI (Gd-EOB-MRI) in the evaluation of colorectal hepatic metastases. MATERIALS AND METHODS: In all, 111 patients with colorectal cancers were enrolled in this study. Of the 112 metastases identified in 46 patients, 31 in 18 patients were confirmed histologically and the remaining 81 in 28 patients were confirmed by follow-up imaging. CE-CT, CE-US, SPIO-MRI, and Gd-EOB-MRI were evaluated. Mean (of three readers, except for CE-US) area under the receiver operating characteristic curve (A(z) ), sensitivities, and positive predictive values (PPV) were calculated. Each value was compared to the others by variance z-test or chi-square test with Bonferroni correction. RESULTS: For all lesions, mean A(z) and sensitivity of Gd-EOB-MRI (0.992, 95% [56/59]) were significantly greater than those of CE-CT (0.847, 63% [71/112]) and CE-US (0.844, 73% [77/106]). For lesions ≤1 cm, mean A(z) and sensitivity of Gd-EOB-MRI (0.999, 92% [22/24]) were significantly greater than those of CE-CT (0.685, 26% [13/50]) and CE-US (0.7, 41% [18/44]). Mean A(z) (95% CI) of SPIO-MRI for all lesions (0.966 [0.929-0.987]) and lesions ≤ 1 cm (0.961 [0.911-0.988]) were significantly greater than those of CE-CT and CE-US. Mean sensitivity of SPIO-MRI for lesions ≤1 cm (63%, 26/41) was significantly greater than that of CE-CT. CONCLUSION: Gd-EOB-MRI and SPIO-MRI were more accurate than CE-CT and CE-US for evaluation of liver metastasis in patients with colorectal carcinoma.

Diagnosis of peritoneal dissemination: comparison of 18F-FDG PET/CT, diffusion-weighted MRI, and contrast-enhanced MDCT.

OBJECTIVE: The purpose of this study was to compare the diagnostic performance of (18)F-FDG PET/CT, MRI with and without diffusion-weighted imaging (DWI), and contrast-enhanced MDCT in the detection of peritoneal dissemination of malignant tumors. MATERIALS AND METHODS: We retrospectively evaluated the cases of 107 patients who underwent PET/CT and 130 patients who underwent MRI and contrast-enhanced MDCT. Twenty-six patients who underwent PET/CT and 23 who underwent MRI and contrast-enhanced MDCT were found to have peritoneal dissemination. All images were independently evaluated by two radiologists using a 5-point grading system. The results of PET/CT, T1- and T2-weighted MRI without DWI, MRI with DWI (b = 1,000 s/mm(2)), and contrast-enhanced MDCT were compared patient by patient and lesion by lesion by use of receiver operating characteristics analysis. Sensitivity, specificity, and positive predictive value were calculated and compared by use of the chi-square test. RESULTS: Patient by patient, the area under the receiver operating characteristics curve of MRI without DWI (0.88) was significantly less than that of the other modalities (contrast-enhanced MDCT, 0.91; MRI with DWI, 0.93; PET/CT, 0.97). The sensitivity of PET/CT (94%) was significantly higher than that of MRI without DWI (70%). The specificities of the modalities were not significantly different. In lesion-by-lesion analysis, MRI without DWI had significantly lower sensitivity (56%) than the other modalities (contrast-enhanced MDCT, 76%; MRI with DWI, 84%; PET/CT, 89%). The positive predictive value of PET/CT (93%) was significantly higher than that of the other three modalities (contrast-enhanced MDCT, 73%; MRI without DWI, 70%; MRI with DWI, 72%). CONCLUSION: PET/CT is the most useful technique for pathologic staging in the care of patients with malignant disease. If PET/CT is not available, DWI can be used as a screening tool.

Distinguishing hypervascular pseudolesions of the liver from hypervascular hepatocellular carcinomas with gadoxetic acid-enhanced MR imaging.

PURPOSE: To retrospectively determine findings at gadoxetic acid-enhanced magnetic resonance (MR) imaging in hypervascular pseudolesions that were observed at computed tomography (CT) during hepatic arteriography, with special focus on distinguishing these pseudolesions from hypervascular hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: The institute ethics committee deemed study approval unnecessary. The study population comprised 80 patients (55 men, 25 women) with chronic liver disease who underwent CT during hepatic arteriography and arterial portography, gadoxetic acid-enhanced MR imaging, and follow-up dynamic contrast material-enhanced CT. The diagnosis of 104 pseudolesions and 123 HCCs was confirmed by means of histopathologic or multimodality evaluation. Two radiologists assessed the MR imaging findings of HCCs and pseudolesions in consensus, including the signal intensities (SIs) of the lesions on T2-weighted, diffusion-weighted (DW), and contrast-enhanced hepatocyte-phase images. The findings of nodular pseudolesions and HCCs were compared with the Fisher exact test. Additionally, the hepatocyte-phase SI ratio (ratio of lesion SI to liver SI) for HCCs and pseudolesions was compared by means of the Mann-Whitney U test. RESULTS: There were 62 wedge-shaped, 32 nodular, and 10 linear pseudolesions. On gadoxetic acid-enhanced hepatocyte-phase MR images, 15% of pseudolesions (16 of 104) were hypointense compared with surrounding liver tissue. The mean hepatocyte-phase SI ratio of HCCs (0.65 +/- 0.14 [standard deviation]) was significantly lower (P < .01) than that of the nodular pseudolesions (0.95 +/- 0.11). The optimal cutoff value of hepatocyte-phase SI ratio for distinguishing between HCC and nodular pseudolesion was 0.84. No nodular pseudolesions were visible on DW images. CONCLUSION: Gadoxetic acid-enhanced hepatocyte-phase MR imaging and DW imaging could be used to distinguish hypervascular pseudolesions from hypervascular HCCs; a hepatocyte-phase SI ratio below 0.84 and visibility on DW images were findings specific for HCCs rather than pseudolesions.

Diagnosis of colorectal hepatic metastases: Contrast-enhanced ultrasonography versus contrast-enhanced computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging with diffusion-weighted imaging.

PURPOSE: To compare the diagnostic accuracy of contrast-enhanced ultrasonography (CE-US), contrast-enhanced CT (CE-CT), and superparamagnetic iron oxide-enhanced MRI (SPIO-MRI) with diffusion-weighted imaging (DWI) in the evaluation of colorectal hepatic metastases. MATERIALS AND METHODS: Thirty-six patients with colorectal cancers were prospectively enrolled and retrospectively evaluated. Of the 86 metastases identified, 16 were confirmed histologically and the remaining 70 were confirmed by follow-up imaging. CE-CT and SPIO-MRI + DWI were independently evaluated by two readers, whereas CE-US was evaluated by consensus reading of two different readers. Area under receiver operating characteristic curve (A(z)), sensitivities, and positive predictive values (PPVs) were calculated and compared. RESULTS: For both readers, SPIO-MRI+DWI had significantly greater A(z) (0.879 and 0.904) and sensitivity (78% and 87%) for all lesions compared with CE-CT (0.779 and 0.793; 59% and 59%) and CE-US (0.811; 69%), and significantly greater A(z) (0.783 and 0.837) and sensitivity (56% and 73%) for lesions ≤1 cm compared with CE-CT (0.562 and 0.601; 20% and 22%) and CE-US (0.66; 37%). For lesions >1 cm, there was no significant difference in A(z), sensitivity and PPV between all the image sets. CONCLUSION: SPIO-MRI with DWI was the most reliable modality for evaluation of liver metastases particularly for lesions ≤1 cm.

Liver parenchymal enhancement of hepatocyte-phase images in Gd-EOB-DTPA-enhanced MR imaging: which biological markers of the liver function affect the enhancement?

PURPOSE: To clarify the factors that predict enhancement of the liver parenchyma in hepatocyte-phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging. MATERIALS AND METHODS: Gd-EOB-DTPA-enhanced hepatocyte-phase MR images of 198 patients with chronic liver diseases (Child-Pugh class A in 112 patients, class B in 74 patients, and class C in 12 patients) were retrospectively analyzed. The hepatocyte-phase images were obtained using fat-suppressed T1-weighted gradient-echo images with a 3D acquisition sequence 10 min and 20 min after IV administration of Gd-EOB-DTPA (0.025 mmol/kg body weight). The quantitative liver-spleen contrast ratio (Q-LSC) was calculated using the signal intensities of the liver and spleen. Serum albumin levels, total bilirubin levels, prothrombin activity, and the results of indocyanine green clearance tests (ICGs) were recorded and correlated with the Q-LSC. Logistic regression analysis was performed to analyze which factors predict sufficient liver enhancement using a Q-LSC of 1.5 as a cutoff value. RESULTS: Only ICGs and Child-Pugh classifications showed a statistically significant correlation with the Q-LSC. Logistic regression analysis showed that ICGs were the only factors that accurately predicted liver enhancement on hepatocyte-phase images. CONCLUSION: ICGs were found to be predictors of sufficient liver enhancement on hepatocyte-phase images.

Delay before the hepatocyte phase of Gd-EOB-DTPA-enhanced MR imaging: is it possible to shorten the examination time?

AIM: To examine if it is possible to shorten the examination time of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB)-enhanced MRI by omitting hepatocyte-phase images of 20-min delay time (Im-20) for detecting focal liver lesions. MATERIALS AND METHODS: Four hundred ninety-five malignant focal liver lesions observed on Im-20 in 265 patients were included. The hepatocyte phase was obtained 10 min (Im-10) and 20 min (Im-20) after Gd-EOB injection. Liver enhancement was evaluated using a 4-point scale [excellent/good/poor/non-diagnostic; visual liver-spleen contrast (V-LSC)] and a quantitative liver-spleen contrast ratio (Q-LSC). Two radiologists evaluated lesion conspicuity for assessing the sensitivity of lesion detection. As Im-20 was used as the standard of reference for the lesions, Im-20 artificially had 100% sensitivity. RESULTS: The results showed that although sensitivities and Q-LSC significantly increased from Im-10 to Im-20 (sensitivity/mean Q-LSC: Im-5, 81%/1.4 Im-10, 96%/1.7: Im-20, 100%/1.9), the sensitivity of Im-10 achieved 100% (the same as Im-20) in patients with good/excellent V-LSC or Q-LSC of more than 1.5. On Im-10, 202 patients (77%) were assigned as having good/excellent V-LSC (78%), and 161 (61%) were assigned as having Q-LSC of more than 1.5. CONCLUSION: We concluded that Im-20 can be omitted in at least 61% of the patients.

Imaging of small hepatic metastases of colorectal carcinoma: how to use superparamagnetic iron oxide-enhanced magnetic resonance imaging in the multidetector-row computed tomography age?

PURPOSE: To compare the accuracy of dynamic contrast-enhanced multidetector-row computed tomography (CT) and superparamagnetic iron oxide-enhanced magnetic resonance imaging (MRI) in the evaluation of small hepatic metastases of colorectal carcinoma. MATERIALS AND METHODS: Of 94 patients with colorectal carcinoma analyzed, 76 hepatic metastases (<2 cm) were diagnosed in 17 patients. Superparamagnetic iron oxide (SPIO)-magnetic resonance (precontrast and postcontrast MRI) and dynamic contrast-enhanced multidetector-row CT (dynamic CT [precontrast, arterial, portal-venous, and delayed phase]) were evaluated. The alternative free-response receiver operating characteristic analysis was performed, and the sensitivities and positive predictive values were analyzed. RESULTS: The Az values and sensitivities of portal-venous phase CT, dynamic CT, and SPIO-MRI (0.62/59%, 0.69/61%, and 0.67/61%) were identical. The mean positive predictive value of dynamic CT (82%) was inferior to that of SPIO-MRI (91%). CONCLUSIONS: The diagnostic ability of dynamic CT is identical to that of SPIO-MRI in Az value and sensitivity. Superparamagnetic iron oxide-MRI should be recommended only if an equivocal lesion is detected by dynamic CT.

Diffusion-weighted magnetic resonance imaging for characterization of focal liver masses: impact of parallel imaging (SENSE) and b value.

PURPOSE: To evaluate the impact of parallel imaging (sensitivity encoding [SENSE] technique) on diffusion-weighted (DW) magnetic resonance imaging, compare DW imaging techniques with 2 different b values for characterization of focal hepatic lesions, and determine apparent diffusion coefficient cutoff values. MATERIALS AND METHODS: Seventy-eight patients with 86 lesions were examined with 4 different DW techniques with 2 different b values (400 and 1000 s/mm2) and with/without the use of SENSE. The differences in signal-noise ratio values and image quality between DW images obtained with different techniques were compared using repeated-measures analysis of variance and Friedman test, respectively. A receiver operating characteristic analysis was applied to evaluate the apparent diffusion coefficient values as a discriminating variable to differentiate malignant lesions from benign ones; sensitivity and specificity were calculated. RESULTS: There was no significant difference in the signal-noise ratio value and image quality between DW images obtained with b = 400 s/mm2 without SENSE (DW400) and b = 1000 s/mm2 with SENSE (DW1000SENSE). DW1000SENSE had the highest Az values for discriminating malignant from benign hepatic lesions (0.97) and hemangioma from metastasis (0.89). Using 1.63 x 10(-3) mm2/s as the cutoff value, DW1000SENSE had a sensitivity of 95.2% (40/42) and a specificity of 91.0% (40/44) for differentiating benign from malignant hepatic lesions. Using a cutoff value of 1.45 x 10(-3) mm2/s, DW1000SENSE had a sensitivity of 90.5% (19/21) and a specificity of 93.7% (15/16) for differentiating metastases from hemangiomas. CONCLUSIONS: Diffusion-weighted imaging with a b value of 1000 s/mm2 and SENSE has the potential to differentiate hepatic focal lesions with improved sensitivity and specificity.

Detection of hypervascular hepatocellular carcinoma with multidetector-row CT: single arterial-phase imaging with computer-assisted automatic bolus-tracking technique compared with double arterial-phase imaging.

PURPOSE: To compare single arterial-phase (SAP) computed tomography (CT) imaging with bolus tracking (BT) with double arterial-phase (DAP) CT imaging for detecting hypervascular hepatocellular carcinoma. MATERIALS AND METHODS: The DAP images were obtained at 25 (DAP-early) and 40 seconds (DAP-late) after the start of contrast material injection. All patients underwent SAP-BT imaging where images were obtained 10 seconds after the CT attenuation value of the aorta reached the threshold value of 120 Hounsfield unit (HU) in 29 (group 120-HU), 160 HU in 30 (group 160-HU), and 200 HU in 32 patients (group 200-HU). Attenuation conspicuity with SAP-BT technique was compared with that with DAP technique using repeated-measures analysis of variance. Attenuation conspicuity and mean scan delays with SAP-BT images obtained with different threshold values were compared using analysis of variance. The sensitivities were compared using McNemar and Fisher exact tests. RESULTS: Within all groups, mean attenuation conspicuity with SAP-BT and DAP-late was significantly higher than that with DAP-early. Regarding SAP-BT, mean attenuation conspicuity in group 200-HU (42 +/- 18 HU) was significantly higher than those in groups 120-HU (23 +/- 11 HU) and 160-HU (25 +/- 11 HU). Mean scan delays for SAP-BT were 24.2 seconds in group-120 HU, 26.8 seconds in group-160 HU, and 31.1 seconds in group-200 HU (P < 0.001). The mean sensitivity with SAP-BT technique in group 200-HU (92.7%) was significantly higher than those in groups 120-HU (72.4%) and 160-HU (71.1%). CONCLUSIONS: Single arterial-phase CT scanning with bolus tracking can be effectively used to detect hepatocellular carcinoma when a threshold value of 200 HU is used.

High-b value diffusion-weighted MRI for detecting pancreatic adenocarcinoma: preliminary results.

OBJECTIVE: The objective of our study was to evaluate the usefulness of high-b value diffusion-weighted MRI (DWI) in the detection of pancreatic adenocarcinoma. SUBJECTS AND METHODS: Twenty-six patients with pancreatic adenocarcinoma were included in the study. Twenty-three other patients who were being followed up due to pancreatic diseases other than adenocarcinoma were included as control subjects. All patients and subjects underwent DWI, and the images were evaluated by three blinded radiologists. RESULTS: Receiver operating characteristic (ROC) curve analysis yielded A(z) values (i.e., area under the ROC curve) of 0.998, 0.998, and 0.995 for the three radiologists. The mean sensitivity and specificity for the detection of pancreatic adenocarcinoma were 96.2% and 98.6%, respectively. The kappa values indicating interobserver agreement between different pairs of radiologists were in the category of excellent. CONCLUSION: High-b value DWI allows the detection of pancreatic adenocarcinoma with a high sensitivity and specificity.

MDCT of pancreatic adenocarcinoma: optimal imaging phases and multiplanar reformatted imaging.

OBJECTIVE: The objective of our study was to evaluate the individual contributions of arterial, pancreatic parenchymal, and portal venous phase (PVP) images and the utility of coronal and sagittal multiplanar reformatted (MPR) images in the assessment of pancreatic adenocarcinoma using triple-phase MDCT. MATERIALS AND METHODS: Thirty-one patients with and 35 patients without pancreatic adenocarcinoma underwent triple-phase MDCT. Three radiologists independently attempted to detect pancreatic adenocarcinoma and assess local extension using the MDCT images in five sessions. The first three sessions involved sets of images obtained in arterial phase, pancreatic parenchymal phase, and PVP separately and respectively. In the fourth session, a combination of axial images from all phases was evaluated. During the fifth session, radiologists had access to coronal and sagittal MPR images together with the axial images obtained in all phases. Results were compared with surgical findings using receiver operating characteristic (ROC) analysis and kappa statistics. RESULTS: Regarding tumor detection, the image set composed of coronal and sagittal MPR images and of axial images obtained in all phases had a significantly higher value for the area under the ROC curve (A(Z), 0.98 +/- 0.01) than the other image sets and yielded the highest sensitivity (93.5%). The sensitivity of the arterial phase image set (80.6%) was significantly lower than that of all other image sets. Whereas the image set composed of coronal and sagittal MPR images and axial images obtained in all phases yielded the highest kappa values for all local extension factors evaluated, the image set composed of only arterial phase images yielded the lowest kappa values for almost all of the factors. CONCLUSION: A combination of pancreatic parenchymal phase and PVP imaging is necessary and efficient for the assessment of pancreatic adenocarcinoma. The addition of coronal and sagittal MPR images increased the performance of MDCT, especially in the evaluation of local extension.

High-B-value diffusion-weighted MRI in colorectal cancer.

OBJECTIVE: The purpose of this article is to evaluate the usefulness of high-b-value diffusion-weighted MRI (DW-MRI) in the detection of colorectal adenocarcinoma. CONCLUSION: High-b-value DW-MRI allows detection of colorectal adenocarcinoma with a high sensitivity and specificity.