Clinical significance of SUVmax on preoperative 18F-fluorodeoxyglucose positron emission tomography in patients who underwent R0-esophagectomy for esophageal cancer.

The standardized uptake value (SUV) is a marker of tumor glucose metabolism, detected using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and may reflect tumor aggressiveness. The purpose of this study was to evaluate the clinical significance of maximum SUV (SUVmax) of primary esophageal cancer (EC) lesions. A total of 86 patients with EC who underwent pre-treatment FDG-PET and R0-resection were included in our study. The mean patient age was 65 years, and 87% were men. Histologically, cancers included squamous cell carcinomas, adenocarcinomas, and other tumors in 72, 3, and 11 patients, respectively. Preoperative chemotherapy with or without radiotherapy was performed in 4 and 37 patients, respectively. Measured patient outcomes included the correlation between the SUVmax of the primary EC lesion and clinicopathological factors in patients who did not undergo preoperative treatment (n = 45), and the investigation of relapse-free survival (RFS) according to SUVmax and the relationship between SUVmax and recurrence sites in all patients (n=86). The mean SUVmax was 8.9 ± 4.6, and SUVmax values significantly correlated with tumor invasion depth and stage. The 5-year RFS for the enrolled patients was 57%, and the RFS of patients with SUVmax < 7.0 was better than that of patients with SUVmax ≥ 7.0, with a marginal difference (p = 0.0892). Lymph node recurrences were significantly more common in patients with SUVmax ≥ 7.0, compared to patients with SUVmax < 7.0. Therefore, the SUVmax value of the primary EC lesion before preoperative treatment may be predictive of RFS and lymph node recurrence.

A case of undifferentiated carcinoma of the pancreas mimicking main-duct intraductal papillary mucinous neoplasm (IPMN).

We report here a rare case of undifferentiated carcinoma of the pancreas mimicking main-duct intraductal papillary mucinous neoplasm. In an 80-year-old woman, an approximately 8-mm papillary mass was incidentally detected at the downstream edge of a dilatated main pancreatic duct lumen on CT and MRI. Main pancreatic duct dilatation in the pancreatic body and tail and parenchymal atrophy were observed in the upstream of the mass. Histopathologically, the tumor protruded into the downstream edge of the dilatated main pancreatic duct lumen in the pancreatic body. The tumor cells had highly atypical nuclei and abundant polymorphic structures, and showed positive staining for granulocyte colony-stimulating factor, which led to the diagnosis of undifferentiated carcinoma. A total of 13 cases of undifferentiated carcinoma with intraductal tumor growth have been reported to date. The case report by Bergmann et al. has been the smallest in histopathological specimen, and the present case is the smallest in size detected by radiological images. Since early undifferentiated carcinoma of the pancreas can resemble those of main-duct intraductal papillary mucinous neoplasm in cross-sectional images, we have to consider undifferentiated carcinoma in the differential diagnosis of the solitary and papillary mass with low contrast enhancement in early phase in the main pancreatic duct.

Limited efficacy of (18)F-FDG PET/CT for differentiation between metastasis-free pancreatic cancer and mass-forming pancreatitis.

OBJECTIVE: Differentiation between metastasis-free pancreatic cancer and mass-forming pancreatitis is important to avoid unnecessary operative procedures. This study was aimed at evaluating the efficacy of PET/CT with F-FDG (FDG PET/CT) for the differential diagnosis between them. PATIENTS AND METHODS: FDG-PET/CT was performed in 47 study patients with pancreatic masses and without any detectable metastases, 33 of which cases were finally diagnosed as pancreatic cancer and the other 14 as pancreatitis, and the corresponding imaging data were evaluated retrospectively. The maximal SUV (SUVmax) within the masses were determined at 1 hour and mostly at 2 hours after intravenous injection of FDG. RESULTS: SUVmax at 1 hour in pancreatic cancer was significantly higher than that in mass-forming pancreatitis, and the change in SUVmax from 1- to 2-hour time points was more consistent with pancreatic cancer than with mass-forming pancreatitis. However, there remained considerable overlapping between the SUVmax values of both diseases except either at the higher range for pancreatic cancer (> 7.7 at 1 hour or > 9.98 at 2 hours) or at the lower range for mass-forming pancreatitis (<3.37 at 1 hour or <3.53 at 2 hours). No obvious difference was found in the FDG uptake patterns of the mass areas between both diseases. CONCLUSIONS: Differentiation between metastasis-free pancreatic cancer and mass-forming pancreatitis is difficult by FDG-PET/CT due to considerable overlapping between the SUVmax values of the two diseases, although the differential diagnosis may be possible either at the higher range of SUVmax (> 7.7 at 1 hour or > 9.98 at 2 hours) for pancreatic cancer or at the lower range of SUVmax (<3.37 at 1 hour or <3.53 at 2 hours) for mass-forming pancreatitis.

Autoimmune pancreatitis: assessment of the enhanced duct sign on multiphase contrast-enhanced computed tomography.

PURPOSE: To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the "enhanced duct sign", for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis. MATERIALS AND METHODS: Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n=55), pancreatic carcinoma (n=50), and chronic pancreatitis (n=50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus. RESULTS: The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P<0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%). CONCLUSION: The enhanced duct sign is highly specific of AIP.

Diagnostic value of SPIO-mediated breath-hold, black-blood, fluid-attenuated, inversion recovery (BH-BB-FLAIR) imaging in patients with hepatocellular carcinomas.

PURPOSE: We assessed the value of adding a breath-hold, black-blood, fluid-attenuated, inversion recovery (BH-BB-FLAIR) sequence with a small motion-probing gradient (b=10 s/mm(2)) using superparamagnetic iron oxide (SPIO) to our present studies that utilize SPIO to detect hepatocellular carcinoma (HCC). We used inversion recovery (IR) in a FLAIR sequence to suppress signals from cysts and a low b-value to suppress vessel signals and provide higher signal to noise than that using high b-value diffusion-weighted imaging. Use of SPIO is expected to reduce the signal in both normal liver parenchyma and in most benign lesions. MATERIALS AND METHODS: In 19 patients, we reviewed 38 HCC nodules diagnosed by CT arterioportography (CTAP) and CT during hepatic arteriography (CTHA). We divided SPIO-mediated images into sets, those obtained with and without BH-BB-FLAIR. Six radiologists individually interpreted the 2 image sets and sorted them by their confidence levels for the presence of HCC, and we calculated the area under the receiver operating characteristic (ROC) curve (Az) for each image set. RESULTS: On images obtained with BH-BB-FLAIR after SPIO administration, 33 of the 38 HCC nodules appeared as areas of high signal and cyst signal was extinguished. The ROC analysis showed significantly higher Az values in the set with BH-BB-FLAIR (0.89) than in the set without (0.83). CONCLUSIONS: Adding BH-BB-FLAIR to existing SPIO-mediated imaging protocols improved detection of HCC nodules and added only 24 s to the scan time.

Stenosis of the third portion of the duodenum due to bleeding from the anterior pancreaticoduodenal artery: assessment by multiphase contrast-enhanced examination with multislice CT.

BACKGROUND: This study was undertaken to analyze the CT findings for the rare pathological process that stenosis of the third portion of the duodenum was presumed to be caused by bleeding from the anterior pancreaticoduodenal artery. METHODS: Four consecutive patients presenting with frequent vomiting, who did not have well-known underlying disorders causing duodenal stenosis, were retrospectively recruited. Multiphase contrast-enhanced CT examinations were performed with 0.5- or 1-mm collimation. Two radiologists evaluated 2-mm axial and multiplanar reformatted images. RESULTS: In all patients, endoscopy demonstrated severe edematous stenosis of the third portion of the duodenum not associated with ulcer, bleeding, or neoplasm. The following CT findings were observed in all patients: homogenous swelling of the third portion of the duodenum associated with luminal stenosis in un-enhanced images, a band-like area of lower contrast-enhancement surrounding the walls of the third portion of the duodenum in pancreatic-phase images, and stenosis of the celiac axis. In three patients, aneurysms of the anterior pancreaticoduodenal artery in arterial-phase images were depicted. In the remaining patient, the diameter of the artery was irregular. CONCLUSIONS: Multiphase contrast-enhanced CT examination using a multislice CT scanner helps to establish the diagnosis of this pathological process.

Arteriovenous malformation of the pancreas: assessment of clinical and multislice CT features.

BACKGROUND: This study was undertaken to analyze the clinical and CT features of arteriovenous malformation (AVM) of the pancreas. METHODS: Seven lesions in six consecutive patients (one woman and five men, mean age 51 years) with AVM of the pancreas who underwent multiphase contrast-enhanced CT with 0.5 or 1-mm collimation were retrospectively studied. CT images were evaluated and correlated with angiographic findings by two radiologists. RESULTS: In four patients, the lesions were incidental findings. Two patients presented with abdominal pain and gastrointestinal bleeding, respectively. Serum amylase levels were within normal limits in all patients. The mean size of the lesions was 32.1 mm (3.0-97.3 mm). Conglomeration of strong nodular stains and early enhancement of the portal venous system were observed for all the lesions. The diagnosis of AVM of the pancreas was retrospectively established for all lesions, but was prospectively established for four lesions. The feeding arteries of all lesions were depicted, showing agreement with those observed by angiography performed for four lesions. One lesion showed pseudocyst formation, haziness around the lesion, and strong enhancement of the duodenal wall. CONCLUSION: Multiphase CT examination using multislice CT is useful for diagnosis of AVM of the pancreas, including identification of the feeding arteries.

Intraductal papillary mucinous neoplasm of the pancreas: assessment of the likelihood of invasiveness with multisection CT.

PURPOSE: To evaluate the capabilities of multisection computed tomography (CT) in determining the likelihood of invasiveness of intraductal papillary mucinous neoplasm (IPMN). MATERIALS AND METHODS: The institutional review board approved this research and waived informed consent from the patients. Two radiologists blinded to the pathologic assessment of malignancy or parenchymal invasion of IPMN retrospectively evaluated CT images of 61 consecutive surgically resected tumors (26 adenomas, 15 noninvasive carcinomas, and 20 invasive carcinomas) in patients who underwent multiphase contrast material-enhanced CT with 0.5- or 1-mm collimation. The findings were statistically analyzed by using univariate and multivariate analyses, with the optimal cutoff levels of each continuous parameter determined by generating receiver operating characteristic curves. RESULTS: The following findings showed significant differences among the three groups: maximum diameter of the main pancreatic duct (MPD), size (length of major axis) of the largest mural nodule in the MPD or in any associated cystic lesion, abnormal attenuating area in the surrounding parenchyma, calcification in the lesion, protrusion of the MPD into the ampulla of Vater, and bile duct dilatation. An MPD diameter of 6 mm or larger, a mural nodule of 3 mm or larger, and an abnormal attenuating area were independently predictive of malignancy. A mural nodule of 6.3 mm or larger in the MPD and an abnormal attenuating area were independently predictive of parenchymal invasion. According to these criteria, the sensitivity, specificity, and accuracy for identifying malignancy were 83%, 81%, and 82% and for identifying parenchymal invasion were 90%, 88%, and 89%, respectively. CONCLUSION: Multisection CT is useful for distinguishing among adenoma, noninvasive carcinoma, and invasive carcinoma in patients with IPMN.

CT depiction of small arteries in the pancreatic head: assessment using coronal reformatted images with 16-channel multislice CT.

BACKGROUND: To assess the capabilities of 16-channel multislice CT in acquiring almost exclusively arterial-phase images of the pancreas and depicting small pancreatic arteries in coronal reformatted images. MATERIALS AND METHODS: In 45 consecutive patients, arterial-phase contrast enhancement was measured in the aorta and its branches, portal venous system, and pancreas. Coronal reformatted images of 1.2- or 1.3-mm slice thickness at 0.8- or 0.9-mm intervals were generated from axial images acquired with 0.5-mm collimation. Two radiologists evaluated the quality of imaging in the arterial phase and the visibility of the pancreatic arteries in coronal reformatted images. RESULTS: Mean enhancement in the aorta and its branches was greater than 300 HU, while that in the portal venous system and pancreas was less than 100 HU. The images were judged to be suitable for delineating the pancreatic arteries in all patients. The following arteries were visualized: anterior superior pancreaticoduodenal (39 patients), posterior superior pancreaticoduodenal (41), anterior inferior pancreaticoduodenal (39), posterior inferior pancreaticoduodenal (33), dorsal pancreatic (42), its right branch (34), and transverse pancreatic (37). CONCLUSION: Multislice CT can depict small pancreatic arteries using coronal reformatted images generated from almost exclusively arterial-phase axial images acquired with 0.5-mm collimation.

Application of subsecond rotation scan to helical CT for lung cancer screening.

PURPOSE: To clarify whether the benefit of a reduced effective scan width obtained using a smaller pitch outweighs the disadvantage of increased noise in the application of a subsecond helical CT to mass screenings for lung cancer. MATERIALS AND METHODS: Twenty-two helical CT scans of the lung were obtained in 11 healthy subjects using the following parameters: 1) scan 1 was performed at 120 kVp, 50 mA, 10-mm collimation, 1-second/rotation, helical pitch of 2.0; and 2) scan 2 was performed at 120 kVp, 50 mA, 10-mm collimation, 0.75-second/rotation, helical pitch of 1.5. Computer-generated nodules measuring 10 mm and 6 mm in diameter showing ground-glass opacity were superimposed on these images. The detectability of each nodule was evaluated by six blinded readers using ROC analysis. RESULTS: Detectability of the 6-mm nodules was significantly higher in scan 2 than in scan 1. Detectability of the 10-mm nodules was not significantly different between scans 1 and 2. CONCLUSION: The use of a smaller pitch by employing a subsecond rotation scan in a helical CT for lung cancer screenings improves the detection of small lesions without increasing either the scanning time or radiation dose.

Assessment of anomalous pancreaticobiliary ductal junction with high-resolution multiplanar reformatted images in MDCT.

OBJECTIVE: The objective of our study was to assess the capabilities of MDCT for the diagnosis of an anomalous pancreaticobiliary ductal junction using high-resolution multiplanar reformatted (multiplanar reconstruction) images. MATERIALS AND METHODS: This study included nine patients with and 54 without an anomalous pancreaticobiliary ductal junction confirmed on direct cholangiopancreatography. Multiplanar reconstruction images with 0.5-mm continuous slices were generated from isotropic or nearly isotropic pancreatic phase images. By mainly interpreting the multiplanar reconstruction images using the Scrolling mode, two blinded reviewers independently determined whether the confluence of the pancreatic and biliary ducts joined in the pancreatic parenchyma (in other words, outside the duodenal wall). The results were correlated with the findings of direct cholangiopancreatography. The diagnostic capabilities of CT for revealing associated pancreatobiliary diseases were assessed in patients with this anomaly. RESULTS: Interobserver agreement in the classification of the duct confluence was high (kappa = 0.804). The duct confluence was identified in all patients except four without an anomalous pancreaticobiliary ductal junction. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CT for diagnosing an anomalous pancreaticobiliary ductal junction were 100% (9 of 9 patients), 87% (47 of 54 patients), 89% (56 of 63 patients), 75% (9 of 12 patients), and 100% (47 of 47 patients) in the final decisions, respectively. CT showed all associated pancreatobiliary diseases except bile duct stones in two patients. CONCLUSION: MDCT enabled the diagnosis of an anomalous pancreaticobiliary ductal junction by showing whether the pancreatic and biliary ducts join within the pancreatic parenchyma on high-resolution multiplanar reconstruction images.

The effect of patient age on contrast enhancement during CT of the pancreatobiliary region.

OBJECTIVE: The objective of our study was to assess whether it is possible to reduce the dose and rate of contrast material injection in elderly patients in triple-phase contrast-enhanced CT of the pancreatobiliary region with an MDCT scanner. SUBJECTS AND METHODS: One hundred twelve patients were divided into three groups: contrast injection at 0.08 mL/kg body weight/s (an upper limit of 5 mL/s) over 30 seconds in patients 60 years old or younger (group 1, n = 49), the same contrast injection as group 1 in patients more than 60 years old (group 2, n = 32), and contrast injection at 0.07 mL/kg body weight/s (an upper limit of 4.5 mL/s) over 30 seconds in patients more than 60 years old (group 3, n = 31). Contrast enhancement in the aorta, portal venous system, pancreas, and liver was assessed quantitatively. Two radiologists blinded to the patients' clinical information and the injection protocol used to acquire the CT images graded the degree of contrast enhancement using a 5-point scoring system. The results for the different groups were statistically compared. RESULTS: Contrast enhancement in the main phases for all organs was significantly more intense in group 2 than in groups 1 and 3. Cases in which pancreatic enhancement in the pancreatic phase was graded as excessive were more frequently observed in group 2. No statistically significant differences were observed between groups 1 and 3 in either quantitative or visual assessment for enhancement of any organ in any phase. CONCLUSION: We recommend reducing the dose and rate of contrast material injection by at least 10% for elderly patients undergoing MDCT examination of the pancreatobiliary region.

Diagnostic value of curved multiplanar reformatted images in multislice CT for the detection of resectable pancreatic ductal adenocarcinoma.

The purpose of this study was to assess the usefulness of curved multiplanar reformatted (MPR) images obtained by multislice CT for the depiction of the main pancreatic duct (MPD) and detection of resectable pancreatic ductal adenocarcinoma. This study included 28 patients with pancreatic carcinoma (size range 12-40 mm) and 22 without. Curved MPR images with 0.5-mm continuous slices were generated along the long axis of the pancreas from pancreatic-phase images with a 0.5- or 1-mm slice thickness. Seven blinded readers independently interpreted three sets of images (axial images, curved MPR images, and both axial and curved MPR images) in scrolling mode. The depiction of the MPD and the diagnostic performance for the detection of carcinoma were statistically compared among these images. MPR images were significantly superior to axial images in depicting the MPD, and the use of both axial and MPR images resulted in further significant improvements. For the detection of carcinoma, MPR images were equivalent to axial images, and the diagnostic performance was significantly improved by the use of both axial and MPR images. High-resolution curved MPR images can improve the depiction of the MPD and the diagnostic performance for the detection of carcinoma compared with axial images alone.

Influence of rib structure on detection of subtle lung nodules.

PURPOSE: To access the influence of anatomic noise on the detectability of subtle lung nodules depicted on chest radiographs. MATERIAL AND METHODS: From normal chest radiography images, 132 square regions were extracted, of which the centers were on the upper margin of a rib, the inside of a rib, the lower margin of a rib, and the central region between two adjoining ribs. Simulated nodules were digitally superimposed at the centers of these extracted square images. Twelve radiologists viewed 50 soft-copy images consisting of these 792 processed images, including the noise-added images. The observer's confidence level for the square images containing single nodules was used as an index of observer performance. RESULTS: Results indicated statistically reliable effects of the relationship between rib structures and nodule positions on the detection performance (P < 0.001). The nodule detectability on the images with a center located between two adjoining ribs was significantly the best, whereas it was significantly the worst on the noise-added images with a center located between two adjoining ribs. CONCLUSION: The rib structures overlying a subtle lung nodule on chest X-ray images have a detrimental effect on nodule detection performance as anatomic noise, regardless of the nodule location on ribs.

[Evaluation of change in the optimal image reconstruction phase in retrospective ECG-gated reconstruction].

The purpose of this study was to optimize the reconstruction phase in order to improve depiction of the coronary artery in the relative delay method of the retrospective electrocardiogram (ECG)-gated reconstruction technique using a multi-slice computed tomography (MSCT) scanner with four channels. The following items were evaluated; 1) image quality of the coronary arteriogram, 2) degree of difference between the standard phase corresponding to the diastasis period and the selected phase, which was determined in each case to obtain the best image, and 3) the factors causing the phase difference. The image quality in the selected phase was better than that in the standard phase. A positive correlation was observed between the degree of phase difference and the median value and standard deviation of the heart rate. The degradation of image quality was remarkable in cases showing a large degree of phase difference. A negative correlation was observed between image quality in the selected phase and the degree of phase difference. Individualizing the reconstruction phase is required to improve the image quality of coronary arteriograms with MSCT. It should be noted that the condition of a low and stable heart rate results in reduction in the degree of phase difference, which is useful for the acquisition of better images.

Diagnostic value of multislice computed tomography for pancreas divisum: assessment with oblique coronal reconstruction images.

OBJECTIVES: To assess the capabilities of high-resolution oblique coronal reconstruction images obtained by multislice computed tomography (CT) in diagnosing pancreas divisum. METHODS: This study included 11 patients with and 53 without pancreas divisum confirmed by direct cholangiopancreatography. Two blinded readers retrospectively interpreted oblique coronal reconstruction images with 0.5-mm continuous slices generated from isotropic or nearly isotropic pancreatic phase images with the scrolling mode and assessed the continuity of the ventral pancreatic duct, dorsal pancreatic duct, and main pancreatic duct in the body. The results were correlated with the findings of direct cholangiopancreatography. Other abnormal findings of the pancreatobiliary region on CT were also recorded in patients with pancreas divisum. RESULTS: The sensitivity and specificity of CT for diagnosing pancreas divisum were 100% and 89%, respectively. Computed tomography demonstrated all associated pancreatobiliary diseases. CONCLUSION: High-resolution oblique coronal reconstruction images allow us to make a diagnosis of pancreas divisum by depicting the continuity of the pancreatic ducts.

Three-phase CT examination of the pancreatobiliary region using multislice CT with 1-mm collimation.

PURPOSE: To evaluate the degree of contrast enhancement and accuracy of imaging of the circulatory phase in the first-pass, second-pass, and third-pass acquisitions in the pancreato-biliary region with 1-mm collimation obtained by multislice computed tomography (CT). MATERIALS AND METHODS: In 53 patients, two sequential acquisitions from the porta hepatis to the pancreas were performed during a single breath-hold, followed by a third-pass acquisition including the liver beginning 15 sec after the second-pass acquisition. Contrast enhancement in each acquisition was measured in the aorta, portal vein and its branches, and pancreas. Four experienced radiologists graded using four-point scoring whether or not each acquisition was appropriate for imaging of the arterial phase, pancreatic phase, and portal venous phase. RESULTS: Aortic enhancement was highest at the beginning of the second-pass acquisition. The portal and splenic veins and pancreas showed maximum enhancement in the second-pass acquisition, while the superior mesenteric vein showed maximum enhancement in the third-pass acquisition. In the visual assessment, significantly higher grades were achieved in the first-pass, second-pass, and third-pass acquisitions with regard to imaging of the arterial phase, pancreatic phase, and portal venous phase, respectively. CONCLUSION: Multislice CT permits the acquisition of three distinct circulatory phases (arterial, pancreatic, and portal venous phases) in the pancreatobiliary region with 1-mm collimation.

Multiphase contrast-enhanced CT of the liver with a multislice CT scanner: effects of iodine concentration and delivery rate.

PURPOSE: To determine whether or not high-concentration contrast material is useful in multiphase contrast-enhanced CT of the liver with a multislice CT scanner. MATERIALS AND METHODS: One hundred twenty-four examinations, in which first- and second-pass acquisitions (double arterial phase imaging) were performed during a single breath-hold followed by third-pass acquisition, were randomized into three protocols: contrast injection at 0.07 mL/kg body weight/sec over 30 sec at an iodine concentration of 300 mgI/mL in group 1, contrast injection at 0.06 mL/kg body weight/sec over 30 sec at an iodine concentration of 350 mgI/mL in group 2, and contrast injection at 0.07 mL/kg body weight/sec over 25.7 sec at an iodine concentration of 350 mgI/mL in group 3. Each group received an equivalent iodine dose per kg body weight (2.1 mL/kg of contrast material of 300 mgI/mL). Contrast enhancement in each acquisition was measured in the aorta, portal vein, and liver. RESULTS: No statistically significant differences were seen between groups 1 and 2 in any enhancement in any acquisition. In group 3, aortic enhancement in the first-pass acquisition was significantly more intense than in groups 1 and 2, while portal venous enhancement and hepatic enhancement were equivalent. CONCLUSION: Shortening the injection duration for a given iodine dose with high-concentration contrast material (group 3) can achieve improved arterial enhancement on arterial phase images.

Branch duct-type intraductal papillary mucinous tumor: diagnostic value of multiplanar reformatted images in multislice CT.

The object of this study was to evaluate the usefulness of high-resolution multiplanar reformatted (MPR) images obtained by multislice CT in demonstrating connection between pancreatic cystic lesions and the main pancreatic duct. The study included 27 lesions with connection to the main pancreatic duct and 12 lesions without. All but one of the former lesions were branch duct-type intraductal papillary mucinous tumors (IPMTs). Oblique and curved MPR images with 0.5 mm continuous slices were generated from pancreatic-phase axial images reconstructed with 0.5 mm or 1 mm thickness at 0.5 mm intervals over a 260 mm field of view. The diagnostic capabilities for demonstrating connection with the main pancreatic duct were compared among axial images, MPR images, and both axial and MPR images in combination using the Brier score. The diagnosis in MPR images for demonstrating connection was more certain than that in axial images (P<0.05). Compared with MPR images alone, the use of both axial and MPR images resulted in further improvements in diagnostic performance, although the difference was not statistically significant. The use of high-resolution MPR images significantly improves diagnostic performance for demonstrating connection between pancreatic cystic lesions and the main pancreatic duct, which is useful for the diagnosis of branch duct-type IPMT.

Multi-slice CT of thyroid nodules: comparison with ultrasonography.

PURPOSE: To evaluate the usefulness of multi-slice computed tomography (MSCT) in comparison with ultrasonography (US) for the differentiation of benign from malignant thyroid nodules and the evaluation of tumor extension. MATERIALS AND METHODS: Thirty patients with thyroid nodules (14 malignant, 16 benign) who underwent both MSCT and US participated in the present study. MSCT with contrast enhancement was performed, and 3D shaded volume rendering (SVR) and multiplanar reconstruction (MPR) were employed to differentiate benign from malignant nodules and to evaluate tumor extension. US images were obtained using a 7.5 MHz annular array probe. A three-point rating scale was used for image interpretation, and the kappa statistic was employed to evaluate agreement between MSCT and US. RESULTS: Sensitivity in differentiating benign from malignant nodules was found to be 85.7% for US and 78.6% for MSCT. Disagreement between MSCT and US occurred in assessing the homogeneity of the solid component and the presence of fibrous capsule. In two of seven T4 cases, MPR provided a more accurate diagnosis than US examination in detecting extracapsular invasion. CONCLUSION: For differential diagnosis of thyroid nodules, US was found to be better than MSCT. However, MSCT could be useful for the evaluation of advanced cases with suspicion of extracapsular extension.