Four-dimensional Flow MRI Assessment of Portal Hemodynamics and Hepatic Regeneration after Portal Vein Embolization.

Background Percutaneous transhepatic portal vein (PV) embolization (PVE) is a standard preoperative procedure for advanced biliary cancer when the future liver remnant (FLR) is insufficient, yet the effect of this procedure on portal hemodynamics is still unclear. Purpose To assess whether four-dimensional (4D) MRI flowmetry can be used to estimate FLR volume and to identify the optimal time for this measurement. Materials and Methods This prospective single-center study enrolled consecutive adult patients with biliary cancer who underwent percutaneous transhepatic PVE for the right liver between June 2020 and November 2022. Portal hemodynamics were assessed using 4D flow MRI before PVE and within 1 day (0-day group) or 3-4 days (3-day group) after PVE. FLR volume was measured using CT before PVE and after PVE but before surgery. Blood flow changes were analyzed with the Wilcoxon signed rank test, and correlations with Spearman rank correlation. Results The 0-day group included 24 participants (median age, 72 years [IQR, 69-77 years]; 17 male participants), and the 3-day group included 13 participants (median age, 71 years [IQR, 68-78 years]; eight male participants). Both groups showed increased left PV (LPV) flow rate after PVE (0-day group: from median 3.72 mL/sec [IQR, 2.83-4.55 mL/sec] to 9.48 mL/sec [IQR, 8.12-10.7 mL/sec], P < .001; 3-day group: from median 3.65 mL/sec [IQR, 2.14-3.79 mL/sec] to 8.16 mL/sec [IQR, 6.82-8.98 mL/sec], P < .001). LPV flow change correlated with FLR volume change relative to the number of days from PVE to presurgery CT only in the 3-day group (ρ = 0.62, P = .02; 0-day group, P = .11). The output of the regression equation for estimating presurgery FLR volume correlated with CT-measured volume (ρ = 0.78; P = .002). Conclusion Four-dimensional flow MRI demonstrated increased blood flow in residual portal branches 3-4 days after PVE, offering insights for estimating presurgery FLR volume. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Roldán-Alzate and Oechtering in this issue.

Development of an x-ray-opaque-marker system for quantitative phantom positioning in patient-specific quality assurance.

PURPOSE: We developed an x-ray-opaque-marker (XOM) system with inserted fiducial markers for patient-specific quality assurance (QA) in CyberKnife (Accuray) and a general-purpose linear accelerator (linac). The XOM system can be easily inserted or removed from the existing patient-specific QA phantom. Our study aimed to assess the utility of the XOM system by evaluating the recognition accuracy of the phantom position error and estimating the dose perturbation around a marker. METHODS: The recognition accuracy of the phantom position error was evaluated by comparing the known error values of the phantom position with the values measured by matching the images with target locating system (TLS; Accuray) and on-board imager (OBI; Varian). The dose perturbation was evaluated for 6 and 10 MV single-photon beams through experimental measurements and Monte Carlo simulations. RESULTS: The root mean squares (RMSs) of the residual position errors for the recognition accuracy evaluation in translations were 0.07 mm with TLS and 0.30 mm with OBI, and those in rotations were 0.13° with TLS and 0.15° with OBI. The dose perturbation was observed within 1.5 mm for 6 MV and 2.0 mm for 10 MV from the marker. CONCLUSIONS: Sufficient recognition accuracy of the phantom position error was achieved using our system. It is unnecessary to consider the dose perturbation in actual patient-specific QA. We concluded that the XOM system can be utilized to ensure quantitative and accurate phantom positioning in patient-specific QA with CyberKnife and a general-purpose linac.

Dosimetric impacts of beam-hardening filter removal for the CyberKnife system.

PURPOSE: Equipment refurbishment was performed to remove the beam-hardening filter (BHF) from the CyberKnife system (CK). This study aimed to confirm the change in the beam characteristics between the conventional CK (present-BHF CK) and CK after the BHF was removed (absent-BHF CK) and evaluate the impact of BHF removal on the beam quality correction factors kQ. METHODS: The experimental measurements of the beam characteristics of the present- and absent-BHF CKs were compared. The CKs were modeled using Monte Carlo simulations (MCs). The energy fluence spectra were calculated using MCs. Finally, kQ were estimated by combining the MC results and analytic calculations based on the TRS-398 and TRS-483 approaches. RESULTS: All gamma values for percent depth doses and beam profiles between each CK were less than 0.5 following the 3%/1 mm criteria. The percentage differences for tissue-phantom ratios at depths of 20 and 10 cm and percentage depth doses at 10 cm between each CK were -1.20% and -0.97%, respectively. The MC results demonstrated that the photon energy fluence spectrum of the absent-BHF CK was softer than that of the present-BHF CK. The kQ values for the absent-BHF CK were in agreement within 0.02% with those for the present-BHF CK. CONCLUSIONS: The photon energy fluence spectrum was softened by the removal of BHF. However, no remarkable impact was observed for the measured beam characteristics and kQ. Therefore, the previous findings of the kQ values for the present-BHF CK can be directly used for the absent-BHF CK.

Incidental findings on computed tomography for preoperative assessment before transcatheter aortic valve implantation in Japanese patients.

Extra-cardiovascular incidental findings (IFs) on preoperative computed tomography (CT) are frequently observed in transcatheter aortic valve implantation (TAVI) candidates. However, the backgrounds of TAVI candidates and comorbidities differ based on the race and/or country, and data on IFs in a specific population are not always applicable to another. The aim of this study was to assess the prevalence, type, and clinical impact of IFs in Japanese TAVI candidates. This was a retrospective, single-center, observational study. CT reports of 257 TAVI candidates were reviewed, and IFs were classified as (a) insignificant: findings that did not require further investigation, treatment, or follow-up; (b) intermediate: findings that needed to be followed up or were considered for further investigation but did not affect the planning of TAVI; and (c) significant: findings that required further investigation immediately or affected the planning of TAVI. At least one IF was found in 254 patients (98.8%). Insignificant, intermediate, and significant IFs were found in 253 (98.4%), 153 (59.5%), and 34 (13.2%) patients, respectively. Newly indicated significant IFs were found in 19 patients (7.4%). In 2 patients (0.8%), TAVI was canceled because of significant IFs. In patients who consequently underwent TAVI, the presence of significant IFs was not associated with the duration from CT performance to TAVI [28 (19-40) days vs. 27 (19-43) days, p = 0.74] and all-cause mortality during the median follow-up period of 413 (223-805) days (p = 0.44). Almost all Japanese TAVI candidates had at least one IF, and the prevalence of significant IFs was not negligible. Although the presence of significant IFs was not associated with mid-term mortality, appropriate management of IFs was considered important.

Abnormal Flow Dynamics Result in Low Wall Shear Stress and High Oscillatory Shear Index in Abdominal Aortic Dilatation: Initial in vivo Assessment with 4D-flow MRI.

PURPOSE: To characterize the non-laminar flow dynamics and resultant decreased wall shear stress (WSS) and high oscillatory shear index (OSI) of the infrarenal abdominal aortic dilatation, cardiac phase-resolved 3D phase-contrast MRI (4D-flow MRI) was performed. METHODS: The prospective single-arm study was approved by the Institutional Review Board and included 18 subjects (median 67.5 years) with the dilated infrarenal aorta (median diameter 35 mm). 4D-flow MRI was conducted on a 1.5T MRI system. On 3D streamline images, laminar and non-laminar (i.e., vortex or helical) flow patterns were visually assessed both for the dilated aorta and for the undilated upstream aorta. Cardiac phase-resolved flow velocities, WSS and OSI, were also measured for the dilated aorta and the upstream undilated aorta. RESULTS: Non-laminar flow represented by vortex or helical flow was more frequent and overt in the dilated aorta than in the undilated upstream aorta (P < 0.0156) with a very good interobserver agreement (weighted kappa: 0.82-1.0). The WSS was lower, and the OSI was higher on the dilated aortic wall compared with the proximal undilated segments. In mid-systole, mean spatially-averaged WSS was 0.20 ± 0.016 Pa for the dilated aorta vs. 0.68 ± 0.071 Pa for undilated upstream aorta (P < 0.0001), and OSI on the dilated aortic wall was 0.093 ± 0.010 vs. 0.041 ± 0.0089 (P = 0.013). The maximum values and the amplitudes of the WSS at the dilated aorta were inversely proportional to the ratio of dilated/undilated aortic diameter (r = -0.694, P = 0.0014). CONCLUSION: 4D-flow can characterize abnormal non-laminar flow dynamics within the dilated aorta in vivo. The wall of the infrarenal aortic dilatation is continuously and increasingly affected by atherogenic stimuli due to the flow disturbances represented by vortex or helical flow, which is reflected by lower WSS and higher OSI.

Assessment of Severity in Chronic Thromboembolic Pulmonary Hypertension by Quantitative Parameters of Dual-Energy Computed Tomography.

OBJECTIVE: The objective of this study was to assess the correlation between dual-energy computed tomography quantitative parameters and hemodynamics in patients with chronic thromboembolic pulmonary hypertension. METHODS: Dual-energy computed tomography of 52 chronic thromboembolic pulmonary hypertension patients were evaluated retrospectively. The mean lung perfused blood volume (lung PBV) and the mean pulmonary artery (PA) enhancement measured at pulmonary parenchymal phase were compared with the hemodynamics by Spearman rank correlation coefficient (rs) and receiver operating characteristic analysis. RESULTS: Lung PBV was correlated with mean pulmonary arterial pressure (rs = 0.47, P < 0.001). Pulmonary artery enhancement was correlated with cardiac index (rs = -0.49, P < 0.001) and pulmonary vascular resistance (rs = 0.48, P < 0.001). The areas under the curves were 0.86 for lung PBV to predict mean pulmonary arterial pressure of >50 mm Hg and 0.86 for PA enhancement to predict pulmonary vascular resistance of >1000 dyne·s/cm. CONCLUSIONS: Lung PBV and PA enhancement could be indicators of hemodynamics.

Evaluation of newly implemented dose calculation algorithms for multileaf collimator-based CyberKnife tumor-tracking radiotherapy.

PURPOSE: In the previous treatment planning system (TPS) for CyberKnife (CK), multileaf collimator (MLC)-based treatment plans could be created only by using the finite-size pencil beam (FSPB) algorithm. Recently, a new TPS, including the FSPB with lateral scaling option (FSPB+) and Monte Carlo (MC) algorithms, was developed. In this study, we performed basic and clinical end-to-end evaluations for MLC-based CK tumor-tracking radiotherapy using the MC, FSPB+, and FSPB. METHODS: Water- and lung-equivalent slab phantoms were combined to obtain the percentage depth dose (PDD) and off-center ratio (OCR). The CK M6 system and Precision TPS were employed, and PDDs and OCRs calculated by the MC, FSPB+, and FSPB were compared with the measured doses obtained for 30.8 × 30.8 mm2 and 60.0 × 61.6 mm2 fields. A lung motion phantom was used for clinical evaluation and MLC-based treatment plans were created using the MC. The doses were subsequently recalculated using the FSPB+ and FSPB, while maintaining the irradiation parameters. The calculated doses were compared with the doses measured using a microchamber (for target doses) or a radiochromic film (for dose profiles). The dose volume histogram (DVH) indices were compared for all plans. RESULTS: In homogeneous and inhomogeneous phantom geometries, the PDDs calculated by the MC and FSPB+ agreed with the measurements within ±2.0% for the region between the surface and a depth of 250 mm, whereas the doses calculated by the FSPB in the lung-equivalent phantom region were noticeably higher than the measurements, and the maximum dose differences were 6.1% and 4.4% for the 30.8 × 30.8 mm2 and 60.0 × 61.6 mm2 fields, respectively. The maximum distance to agreement values of the MC, FSPB+, and FSPB at the penumbra regions of OCRs were 1.0, 0.6, and 1.1 mm, respectively, but the best agreement was obtained between the MC-calculated curve and measurements at the boundary of the water- and lung-equivalent slabs, compared with those of the FSPB+ and FSPB. For clinical evaluations using the lung motion phantom, under the static motion condition, the dose errors measured by the microchamber were -1.0%, -1.9%, and 8.8% for MC, FSPB+, and FSPB, respectively; their gamma pass rates for the 3%/2 mm criterion comparing to film measurement were 98.4%, 87.6%, and 31.4% respectively. Under respiratory motion conditions, there was no noticeable decline in the gamma pass rates. In the DVH indices, for most of the gross tumor volume and planning target volume, significant differences were observed between the MC and FSPB, and between the FSPB+ and FSPB. Furthermore, significant differences were observed for lung Dmean , V15 Gy , and V20 Gy between the MC, FSPB+, and FSPB. CONCLUSIONS: The results indicate that the doses calculated using the MC and FSPB+ differed remarkably in inhomogeneous regions, compared with the FSPB. Because the MC was the most consistent with the measurements, it is recommended for final dose calculations in inhomogeneous regions such as the lung. Furthermore, the sufficient accuracy of dose delivery using MLC-based tumor-tracking radiotherapy by CK was demonstrated for clinical implementation.

Quantitative Follow-Up Assessment of Patients with Interstitial Lung Disease by 3D-Curved High-Resolution CT Imaging Parallel to the Chest Wall.

We evaluated the progression of interstitial lung disease (ILD) by three-dimensional curved high-resolution computed tomography (3D-cHRCT) at a constant depth from the chest wall and compare the results to pulmonary function test (PFT) results on a follow-up assessment. We reviewed the patients with ILD who underwent HRCT and concurrent PFTs at least twice from April 2008 to December 2014. Forty-five patients with ILD were enrolled. 3D-cHRCT images of the lung at various depths from the chest wall were reconstructed, and total area (TA), high-attenuation area (HAA) >-500 HU, and %HAA ([HAA/TA] × 100) were calculated. The TA, HAA, and %HAA ratios (follow-up to baseline) were assessed for use in the diagnosis of physiologically progressive ILD (defined as; forced vital capacity [FVC] ratio <0.9 or %diffusing capacity of the lung for carbon monoxide [%DLCO] ratio <0.85 [follow-up to baseline]). Of all ratios obtained from 3D-cHRCT images at 5-30mm depths, the %HAA ratio at 20-mm had the largest area under the receiver operating characteristic curve (0.815, 95 % confidence interval 0.677-0.953). By univariate logistic regression analysis, TA, HAA, and %HAA ratios at 20-mm showed significant correlations with physiologically progressive ILD. 3D-cHRCT imaging performed in parallel with the chest wall offers novel quantitative parameters that are useful for following ILD.

Dosimetric feasibility of using tungsten-based functional paper for flexible chest wall protectors in intraoperative electron radiotherapy for breast cancer.

Intraoperative electron radiotherapy (IOERT), which is an accelerated partial breast irradiation method, has been used for early-stage breast cancer treatment. In IOERT, a protective disk is inserted behind the target volume to minimize the dose received by normal tissues. However, to use such a disk, the surgical incision must be larger than the field size because the disk is manufactured from stiff and unyielding materials. In this study, the applicability of newly developed tungsten-based functional paper (TFP) was assessed as an alternative to the existing protective disk. The radiation-shielding performance of the TFP was verified through experimental measurements and Monte Carlo simulations. Percentage depth dose curves and lateral dose profiles with and without TFPs were measured and simulated on a dedicated IOERT accelerator. The number of piled-up TFPs was changed from 1 to 40. In the experimental measurements, the relative doses at the exit plane of the TFPs for 9 MeV were 42.7%, 9.2%, 0.2%, and 0.1% with 10, 20, 30, and 40 TFPs, respectively, whereas those for 12 MeV were 63.6%, 27.1%, 8.6%, and 0.2% with 10, 20, 30, and 40 TFPs, respectively. Slight dose enhancements caused by backscatter radiation from the TFPs were observed at the entrance plane of the TFPs at both beam energies. The results of the Monte Carlo simulation indicated the same tendency as the experimental measurements. Based on the experimental and simulated results, the radiation-shielding performances of 30 TFPs for 9 MeV and 40 TFPs for 12 MeV were confirmed to be acceptable and close to those of the existing protective disk. The findings of this study suggest the feasibility of using TFPs as flexible chest wall protectors in IOERT for breast cancer treatment.

Differentiation of focal-type autoimmune pancreatitis from pancreatic carcinoma: assessment by multiphase contrast-enhanced CT.

OBJECTIVES: To evaluate the utility of multiphase contrast-enhanced computed tomography (CT) findings alone and in combination for differentiating focal-type autoimmune pancreatitis (f-AIP) from pancreatic carcinoma (PC). METHODS: The study group comprised 22 f-AIP lesions and 61 PC lesions. Two radiologists independently evaluated CT findings. Frequencies of findings were compared between f-AIP and PC. Statistical, univariate and multivariate analyses were performed. RESULTS: Homogeneous enhancement during the portal phase (AIP, 59 % vs. PC, 3 %; P < 0.001), dotted enhancement during the pancreatic phase (50 % vs. 7 %; P < 0.001), duct-penetrating sign (46 % vs. 2 %; P < 0.001), enhanced duct sign (36 % vs. 2 %; P < 0.001) and capsule-like rim (46 % vs. 3 %; P < 0.001) were more frequently observed in AIP. Ring-like enhancement during the delayed phase (5 % vs. 46 %; P < 0.001) and peripancreatic strands with a length of at least 10 mm (5 % vs. 39 %; P = 0.001) were more frequently observed in PC. AIP was identified with 82 % sensitivity and 98 % specificity using four of these seven findings. Multivariate analysis revealed significant differences in dotted enhancement (P = 0.004), duct-penetrating sign (P < 0.001) and capsule-like rim (P = 0.007). CONCLUSIONS: The combination of CT findings may allow improvements in differentiating f-AIP from PC. KEY POINTS: • f-AIP can mimic PC on imaging findings. • The differentiation of f-AIP from PC is important in patient management. • Some CT findings can be used to identify AIP. • The combination of CT findings will improve differentiation from PC.

Assessment of percutaneous transhepatic portal vein embolization with portal vein stenting for perihilar cholangiocarcinoma with severe portal vein stenosis.

BACKGROUND: The aim of the present study was to assess the clinical efficiency of portal vein (PV) stenting when performed with preoperative percutaneous transhepatic portal vein embolization (PTPVE) in patients with severe PV stenosis due to tumor invasion. METHODS: Between 2007 and 2013, four consecutive patients (one male, three females; mean age, 52 years; age range, 25-73 years) with perihilar cholangiocarcinoma and PV stenosis underwent PTPVE and PV stenting. Patients were analyzed with regard to the procedure, hypertrophy of the future remnant liver (FRL), and plasma clearance rate of indocyanine green by the FRL (ICGK-F). Further, the %FRL volume increase in PTPVE was compared between the stenting group and the usual PTPVE group who have perihilar cholangiocarcinomas without PV stenosis. RESULTS: Preoperative PTPVE with PV stenting was successfully performed and portal flow to the FRL improved after stenting in all four patients. The %FRL volume increase was 18-60% (mean, 34%) in the stenting group and was 12-51% (mean, 21%) in the usual PTPVE group. The ICGK-F value after PTPVE exceeded 0.05 in all four patients. All patients achieved R0 resection. CONCLUSIONS: Preoperative PTPVE with PV stenting appears to be feasible in cases of severe PV tumor invasion and stenosis. This procedure may allow a broader indication for surgery.

Numerical assessment of cholesteatoma by signal intensity on non-EP-DWI and ADC maps.

OBJECTIVE: To establish a methodology for magnetic resonance imaging (MRI) assessment in the diagnosis of cholesteatoma using signal intensity on BLADE diffusion-weighted MRI (BLADE-DWI) and apparent diffusion coefficient (ADC) mapping. STUDY DESIGN: Retrospective case series. SETTING: University hospital. PATIENTS: Participants comprised 29 patients who underwent middle ear surgery and in whom preoperative differential diagnosis between cholesteatoma and other middle ear diseases was difficult using local and computed tomographic findings and required BLADE-DWI. INTERVENTION: Signal intensity ratio (SIR) between the affected region of the middle ear and the pons measured by BLADE-DWI and on ADC maps was evaluated numerically. SIR in an area located near the target lesion in each case was used as a control. Values were compared between both cases in which cholesteatoma was histopathologically confirmed (cholesteatoma group) and cases in which cholesteatoma was excluded on histopathologic examination (noncholesteatoma group). MAIN OUTCOME MEASURES: Imaging and histopathologic findings. RESULTS: SIR on BLADE-DWI was significantly higher in the cholesteatoma group than in the noncholesteatoma group, although both groups showed significantly higher SIR in the target lesion than in the control area. Moreover, SIR on ADC maps was significantly lower in the cholesteatoma group than in the noncholesteatoma group. The clear cutoff value of SIR on ADC maps was 1.5. CONCLUSION: The combination of BLADE-DWI and ADC mapping offers a useful imaging tool for accurate detection of middle ear cholesteatoma. Use of SIR can numerically differentiate between cholesteatoma and noncholesteatoma.

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.

Study of the cost-benefit analysis of electronic medical record systems in general hospital in China.

Electronic medical record (EMR) systems have been proposed as technology to improve the quality of patient care, decrease medical errors, control and reduce medical expenditure, however the financial effects have not yet been as well documented in China. We presented a net financial cost-benefit analysis of implementing electronic medical record systems in general hospital in China. The data, which were obtained from studies of the general hospital and the published literature, collected from 15 consecutive fiscal months from May 1, 2009 to August 30, 2010. We performed a perspective cost-benefit study to analyze the financial effects of EMR system implementing. The reference strategy for comparisons was the traditional paper-based medical record. The net financial benefits or costs for a 6-year period were calculated. All data were adjusted for inflation. The totally assessed net benefit from implementing an EMR system for a 6-year period was $559,025 in the general hospital. Benefits accrue primarily from savings in new medical record creation, decreased full-time-equivalent (FTE) employees, saving of adverse drug events (ADEs) and dose errors, improved charge capture and decreased billing errors. In this model, the time of return on investment is 3.00 years. In one-way sensitivity analysis, the model was most sensitive in new medical record creation; the net benefit varied from $398,057 to $719,992. The five-way sensitivity analysis with the most pessimistic and optimistic assumptions showed results ranging from a $76,970 net cost to a $1,062,122 net benefit; the pessimistic time of return on investment is 5.38 years. An EMR system cost-benefit analysis can rapidly demonstrate a positive return on investment when implemented in hospitals. The magnitude of the return is sensitive to several key factors.

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.