Enhancement In Portal Venous Phase Research Articles

The application of dual-phase enhanced CT scan in distinguishing adrenal ganglioneuromas from adrenal lipid-poor adenomas

BackgroundThe utility of dual-phase enhanced computerized tomography (CT) scan in distinguishing adrenal ganglioneuromas from lipid-poor adenomas has not been reported. We aimed to retrospectively compare dual-phase enhanced CT findings which were helpful in distinguishing adrenal ganglioneuromas from adrenal lipid-poor adenomas.MethodsWe estimated the dual-phase enhanced CT findings of 258 adrenal masses (42 ganglioneuromas, 216 lipid-poor adenomas) in 258 patients from July 2008 to July 2020 with ganglioneuromas and July 2016 to July 2020 with lipid-poor adenomas. The CT features between ganglioneuromas and lipid-poor adenomas were compared using independent two-sample t test, Mann–Whitney test, and ROC analysis.ResultsSignificant differences were detected in CT value of unenhanced (CTU), CT value of arterial phase (CTA), CT value of venous phase (CTV), degree of enhancement in arterial phase, degree of enhancement in portal venous phase, age, tumor size [longest dimension, shortest dimension, mean dimension], shape, calcification between the ganglioneuroma and lipid-poor adenoma groups (P < 0.05). The results of receiver operating characteristics (ROC) analyses showed that areas under ROC curves of CTU, CTA and CTV were 0.713, 0.878, and 0.914, respectively. When the cut-off values were set at 22.5 HU, 51.5 HU, and 53.5 HU for CTU, CTA, and CTV, respectively, the three parameters had a sensitivity of 46.8%, 67.6%, and 88.0% and a specificity of 100%, 100%, and 88.1% in distinguishing ganglioneuromas from lipid-poor adenomas.ConclusionsDual-phase enhanced abdominal CT can exhibit some of the primary imaging characteristics of ganglioneuromas and lipid-poor adenomas used to distinguish between these two entities.

The Relationship between Ultrasonographic Features of Hepatocellular Carcinoma and the Severity of Hepatocellular Carcinoma and the Expression of PTEN and Tg737.

To investigate the relationship between the ultrasonographic features of hepatocellular carcinoma (HCC) and the severity of HCC and the expression of tumor suppressor genes PTEN and Tg737, 90 patients with primary liver cancer are selected as the study subjects. The enhancement of liver tumor in arterial phase, portal venous phase, and delayed phase is observed by contrast-enhanced ultrasound (CEUS) before operation, and the echo intensity is compared with that of surrounding liver parenchyma. Immunohistochemistry is used to detect the expression of PTEN and Tg737 in hepatocellular carcinoma and paracancerous tissues. (1) In HCC, CEUS enhancement is characterized by rapid enhancement in arterial phase, enhancement in portal venous phase and delayed phase, and decreased hypoechoic changes. About 78.0% of the stage I-II liver cancer and 85.0% of the stage III-IV liver cancer show rapid enhancement and high echo in the arterial phase; only 8.0% of the stage I-II liver cancer shows moderate echo changes in the portal venous phase, while 32.5% (13/40) stage III-IV liver cancer shows moderate echo changes in the portal venous phase. (2) The positive rates of PTEN in liver cancer tissues and paracancerous tissues are 21.1% (19/90) and 70.0% (63/90), respectively, and the difference is statistically significant. The positive rates of Tg737 in liver cancer tissues and paracancerous tissues are 17.8% (16/90) and 75.6% (68/90), respectively, and the difference is statistically significant. Compared with PTEN and Tg737 negative groups, the ascending slope (RS) and initial elimination time (WT) of PTEN and Tg737 positive groups are significantly higher, indicating that the inflow velocity of contrast medium in the positive group is higher, the outflow time is shorter, and the lesions shows low enhancement rapidly. However, the expression of PTEN and Tg737 had no significant difference in maximal intensity (IMAX), peak time (TTP), and mean transit time (mTT). (3) Correlation analysis shows that the immunohistochemical scores of PTEN and Tg737 are not significantly correlated with IMAX, mTT, and TTP but positively correlated with RS (r = 0.359,P < 0.05), suggesting that the positive expressions of PTEN and Tg737 are negatively correlated with the inflow velocity of contrast medium. The immunohistochemical scores of PTEN and Tg737 are negatively correlated with WT, which indicated that the higher the expression intensity of PTEN is, the longer the outflow time of contrast medium is and the slower the outflow of contrast medium is. There is a significant correlation between the expression of PTEN and Tg737 proteins and CEUS parameters in hepatocellular carcinoma.

Contrast-Enhanced Ultrasound of Congenital and Infantile Hemangiomas: Preliminary Results From a Case Series.

OBJECTIVE. The contrast-enhanced ultrasound (CEUS) imaging features of hepatic vascular tumors in infants, including infantile hemangioma (IH) and congenital hemangioma (CH), are not well reported. Frequent inaccurate use of lesion terminology in the literature has created diagnostic confusion. The purpose of this study is to describe the CEUS features of IH and CH. MATERIALS AND METHODS. Ten patients, ranging in age from 8 days to 16 months, with hepatic vascular tumors were included for retrospective analysis. Gray-scale ultrasound, color Doppler ultrasound, and CEUS features were reviewed, and interobserver kappa coefficients were calculated. Final diagnoses were clinically determined by a pediatrician with expertise in vascular anomalies except in one patient who underwent surgical excision. RESULTS. Of the 10 patients, five had CHs and five had IHs. All 10 lesions were hyperenhancing in the early arterial phase. In the portal venous phase, four of five (80%) CHs showed hyperenhancement relative to normal liver parenchyma, whereas four of five (80%) IHs showed isoenhancement. In the late phase, washout of contrast material was seen in three of five (60%) IHs, whereas one IH remained isoenhancing and one IH was hyperenhancing. None of the CHs showed late washout. Interobserver kappa coefficients for CEUS features ranged from 0.60 to 1.00. CONCLUSION. Except for the CEUS feature portal venous phase enhancement (κ = 0.60), good to excellent (κ = 0.74-1.00) agreement about CEUS features of IHs and CHs was observed. A significant proportion of IHs (60%) showed washout at delayed phase imaging, which has also been reported with malignancies. Recognition of the overlap in imaging appearance of these two entities is vital to preventing misdiagnosis of malignancy.

Preoperative Computed Tomography Features of Intrahepatic Cholangiocarcinoma for Predicting Lymph Node Metastasis and Overall Survival.

The aims of this study were to compare the difference of computed tomography (CT) features between intrahepatic cholangiocarcinomas (ICCs) with and without lymph node metastasis (LNM) and to construct a nomogram to predict LNM and overall survival preoperatively. Clinicopathological and contrast-enhanced CT features of 63 patients with ICC were analyzed. Multivariate logistic regression analysis was performed to construct a nomogram to predict LNM preoperatively. Survival curves were drawn with the Kaplan-Meier method, and survival difference was compared. Intrahepatic cholangiocarcinomas with and without LNM differed significantly in clinical symptoms, tumor location, morphologic classification, arterial phase enhancement degree-mean, arterial phase enhancement degree-max, portal venous phase enhancement degree-max, equilibrium phase (EP) enhancement ratio, EP CT value-max, and EP CT value-max/liver. A nomogram based on morphologic classification, EP CT value-max, and EP enhancement ratio was constructed to predict LNM with an area under curve of 0.814 (P < 0.001). Patients with ICC with LNM risk of 0.20 or greater based on the nomogram showed a significantly poorer overall survival than those with LNM risk less than 0.20 (39.5 ± 5.2 vs 51.1 ± 4.7 months). Preoperative CT features of ICCs differed significantly between those with and without LNM. Nomogram based on those features could predict LNM and overall survival even better than the N stage.

MRI feature of hepatic epithelioid hemangioendothelioma

Objective To discuss the MRI findings of hepatic epithelioid hemangioendothelioma (EHE). Methods MRI and clinical data of 8 EHE patients confirmed by pathology in PLA General Hospital were retrospectively analyzed. Results 8 patients included 3 male and 5 female. 1 patient had single lesion and 7 patients had multiple lesions. A total of 162 lesions were detected and most of the lesions were in the peripheral liver. For T1WI, 100 lesions (61.7%) showed slightly low signal, and 62 lesions (38.3%) showed lower signal intensity in the center of the lesion and appeared as target sign . For T2WI, the center of 29 lesions (17.9%) showed two-loop target sign , 66 lesions (40.7%) showed three-loop target sign , and 67 lesions (41.4%) showed slightly homogeneous higher signal. For DWI, 116 lesions (71.6%) showed halo-like high signal and 46 lesions (28.4%) showed uniform high signal. For dynamic enhancement, the lesions showed slightly enhancement in the arterial phase, and persistent enhancement in portal venous phase, the center of 122 lesions (about 75.3%) showed enhancement and 40 lesions (24.7%) showed no enhancement in delayed phase. 1 patient with hepatobiliary specific contrast was enhanced in hepatobiliary phase. Hepatic capsule depression was observed in 30 lesions. 7 lesions appeared as lollipop sign , and were enveloped in 16 lesions. Conclusion MRI, DWI and dynamic contrast-enhanced scanning of EHE in liver are characteristic, which is helpful for qualitative diagnosis before surgery. Key words: Epithelioid hemangioendothelioma; Magnetic resonance imaging (MRI); Diffusion weighted imaging (DWI)

Correlation between the CT features and malignancy risk of small (≤5 cm) gastric stromal tumors

Objective: To evaluate the correlation between computed tomography (CT) features and malignancy risk category of small (≤5 cm) gastric stromal tumors (GST), in order to provide an image reference for preoperative assessment and intraoperative pathological diagnosis. Methods: Eighty-three patients with surgically and pathologically proven GST (≤5 cm) between January 2011 and November 2015 were recruited, and their clinical, pathological and CT data were retrospectively analyzed. According to the pathological results and malignancy risk category, the patients were divided into 2 groups, the benign biological behavior group (very low and low risk) and malignant biological behavior group (intermediate and high risk). The clinical, pathological and CT imaging findings of the two groups were analyzed. Based on the tumor diameter, the receiver operating characteristic curve (ROC) was applied to evaluate the sensitivity, specificity and the best cut-off point for distinguishing the malignancy risk between the two groups. Results: The lobulation and ulceration of the tumors presented statistically significant difference for the malignancy risk between the two groups (χ(2)=6.273 and 4.163, respectively; all P<0.05), but there was no significant difference in the sex, clinical symptoms, serum ferritin, tumor site, growth pattern, cystis degeneration and calcification (all P>0.05). No statistically significant differences were detected for the tumor CT value, arterial CT value, venous CT value, degrees of enhancement in arterial phase (DEAP), enhancement in portal venous phase (DEPP), and patient's age for distinguishing the malignancy risk between the two groups (all P>0.05). On the other hand, significant differences were found in the maximum diameter (Dmax) of tumor and the minimum diameter (Dmin) of tumor (t=-3.256 and -3.466, respectively; all P<0.05). When the cut-off point of Dmax was 1.6 cm, the area under the ROC curve, sensitivity and specificity were 0.704, 92.3% and 75.4%, respectively. When the cut-off point of Dmin was 1.5 cm, the area under the ROC curve, sensitivity and specificity were 0.713, 88.5% and 71.9%, respectively. Conclusion: CT features of the GST (≤5 cm) may predict, before surgery, the malignancy risk of small gastric stromal tumors, and provide the an image reference for preoperative assessment and intraoperative pathological diagnosis of the disease.

Can MDCT or EUS features predict the histopathological grading scheme of pancreatic neuroendocrine neoplasms?

To identify whether the features of preoperative MDCT or EUS could predict the histopathological grading scheme of pancreatic neuroendocrine neoplasms (pNENs). A total of 25 patients with pNENs were enrolled in the present study. The qualitative and quantitative variables were reviewed. The qualitative variables included location, contour, border, necrosis, intratumoral vessel, homogeneity, calcification, peripancreatic fat/vessel infiltration, pancreatic duct dilatation, mass within pancreas, lymphadenopathy and hepatic metastasis on MDCT and border, echogenicity, cystic/solid and blood flow on EUS. The quantitative variables included long diameter (LD), short diameter (SD), unenhanced mass attenuation (UMA), unenhanced pancreatic attenuation (UPA), arterial phase mass attenuation (APMA), arterial phase pancreatic attenuation (APPA), portal venous phase mass attenuation (PVPMA), portal venous phase pancreatic attenuation (PVPPA), arterial phase enhancement degree (APED) and portal venous phase enhancement degree (PVPED). In addition, sex and age were also evaluated. Histopathological classifications met the criterion of 2010 edition WHO Histopathological Classifications. Kruskal-Wallis test and Boruta algorithm were conducted. Lymphadenopathy and peripancreatic fat or vascular invasion foretold higher histopathological grading level while well-defined border on EUS image lower grading level. Lymphadenopathy, border on EUS image and peripancreatic fat or vascular invasion can predict the histopathological grading scheme of pNENs.

3:18 PMAbstract No. 338 - Pre and post-procedural evaluation of imaging biomarkers after radioembolization for hepatocellular carcinoma as an indicator of progression

The purpose of this study is to evaluate possible imaging biomarkers on contrast-enhanced CT and MRI exams that predict local progression per modified Response Evaluation Criteria in solid tumors (mRECIST) criteria post radioembolization of hepatocellular carcinoma (HCC). Among patients who underwent radioembolization for HCC between May 1, 2005 and May 1, 2015 at a single institution, 34 patients had adequate pre and at least 2 post-procedural exams. Local response to treatment was classified as progressive (PD) or stable disease (SD) using mRECIST. Imaging markers, including portal venous phase enhancement (PVE), lobulated enhancement (LE), presence of arterioportal shunting (APS), and portal vein thrombosis (PVT) were assessed in each imaging examination. Wilcoxen Rank-Sum (WRS) and log-rank analyses were performed to establish statistically significant differences in local progression free survival (LPFS). The mean imaging follow-up time was 12.64 months. Local progression was seen in 25 patients (73.5%) following radioembolization. Average time to progression was 2.9 months. PVT, APS, and PVE seen on pre or post-procedural imaging were not significant predictors of LPFS. LE on immediate post-procedural imaging was a significant predictor of progression by WRS (p=0.039) and log-rank analysis (p=0.037), however LE on pre-procedural imaging was not a significant predictor. 9 patients with and 0 patients without progression showed LE on pre or post-procedural imaging, respectively. PVT, APS, and portal venous enhancement were not statistically significant predictors of local progression, whereas immediate post-procedural LE demonstrated a statistically significant decrease in LPFS in patients with hepatocellular carcinoma treated with radioembolization.

Differentiation of mass-forming intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma: based on the multivariate analysis of contrast-enhanced computed tomography findings.

We aim to gain further insight into identifying differential radiological features of mass-forming intrahepatic cholangiocarcinoma (mICC) from poorly differentiated hepatocellular carcinoma (pHCC) on contrast-enhanced computed tomography (CT). 107 patients with pathologically confirmed mICC (n=48) and pHCC (n=59) who had undergone preoperative contrast-enhanced CT were enrolled. Qualitative analysis of CT images were evaluated for tumor demarcation, shape, presence of satellite nodules, capsular retraction, biliary involvement, intratumoral arteries, tortuous tumoral vessels, vascular invasion, portal vein tumor thrombus, arterial enhancement pattern, portal venous phase enhancement, and washout pattern. Quantitative analysis was performed for mean attenuation of tumor and tumor-to-liver contrast during each phase. The degree of arterial enhancement was graded based on quantitative measurements. A lobulated shape, indistinct margin, peripheral rim enhancement in the arterial phase, and the presence of bile duct dilatation were CT features favoring mICC, whereas a round shape, partially indistinct margin, heterogeneous enhancement in the arterial phase, washout pattern and the presence of tortuous tumoral vessels were CT features favoring pHCC in the univariate analysis (P<0.05). Tumor-to-liver contrast of pHCC was greater than that of mICC during the arterial phase (P=0.015). In the multivariate analysis, bile duct dilatation, tortuous tumoral vessels, and a washout pattern were independent CT features for distinguishing between the two types. (P=0.003, P=0.003, P=0.044, respectively). The absence of a washout pattern and tortuous tumoral vessels and presence of bile duct dilatation are more indicative of mICC than of pHCC on contrast-enhanced CT.

Detection of small (≤ 2 cm) pancreatic adenocarcinoma and surrounding parenchyma: correlations between enhancement patterns at triphasic MDCT and histologic features

BackgroundThe aim is to assess the time-density curves (TDCs) and correlate the histologic results for small (≤ 2 cm) PDA and surrounding parenchyma at triphasic Multidetector-row CT (MDCT).MethodsTriphasic MDCT scans of 38 consecutive patients who underwent surgery for a small PDA were retrospectively reviewed. The TDCs were analyzed and compared with histologic examination of the PDA and pancreas upstream/downstream in all cases. Three enhancement patterns were identified: 1) enhancement peak during pancreatic parenchymal phase (PPP) followed by a rapid decline on portal venous phase (PVP) and delayed phase (DP) at 5 minutes (type 1 pattern: normal pancreas); 2) maximum enhancement in PVP that gradually decreases in DP (type 2 pattern: mild chronic pancreatitis or PDA with mild fibrous stroma); 3) progressive enhancement with maximum peak in DP (type 3 pattern: severe chronic pancreatitis or PDA with severe fibrous stroma). A p value less than 0.05 was considered statistically significant. Sensitivity was calculated for PDA detection and an attenuation difference with the surrounding tissue of at least 10 HU was considered.ResultsPDA showed type 2 pattern in 5/38 cases (13.2%) and type 3 pattern in 33/38 cases (86,8%). Pancreas upstream to the tumor had type 2 pattern in 20/38 cases (52,6%) and type 3 pattern in 18/38 cases (47,4%). Pancreas downstream to the tumor had type 1 pattern in 19/25 cases (76%) and type 2 pattern in 6/25 cases (24%). Attenuation difference between tumor and parenchyma upstream was higher of 10 UH on PPP in 31/38 patients (sensitivity = 81.6%), on PVP in 29/38 (sensitivity = 76.3%) and on DP in 17/38 (sensitivity = 44.7%). Attenuation difference between tumor and parenchyma downstream was higher of 10 UH on PPP in 25/25 patients (sensitivity = 100%), on PVP in 22/25 (sensitivity = 88%) and on DP in 20/25 (sensitivity = 80%). Small PDAs were isodense to the pancreas upstream to the tumor, and therefore unrecognizable, in 8 cases (8/38; 21%) at qualitative analysis and in 4 cases (4/38; 10,5%) at quantitative analysis.ConclusionsThe quantitative analysis increases the sensitivity for detection of small PDA at triphasic MDCT.

Interobserver agreement of semi-automated and manual measurements of functional MRI metrics of treatment response in hepatocellular carcinoma

PurposeTo assess the interobserver agreement in 50 patients with hepatocellular carcinoma (HCC) before and 1 month after intra-arterial therapy (IAT) using two semi-automated methods and a manual approach for the following functional, volumetric and morphologic parameters: (1) apparent diffusion coefficient (ADC), (2) arterial phase enhancement (AE), (3) portal venous phase enhancement (VE), (4) tumor volume, and assessment according to (5) the Response Evaluation Criteria in Solid Tumors (RECIST), and (6) the European Association for the Study of the Liver (EASL). Materials and methodsThis HIPAA-compliant retrospective study had institutional review board approval. The requirement for patient informed consent was waived. Tumor ADC, AE, VE, volume, RECIST, and EASL in 50 index lesions was measured by three observers. Interobserver reproducibility was evaluated using intraclass correlation coefficients (ICC). P<0.05 was considered to indicate a significant difference. ResultsSemi-automated volumetric measurements of functional parameters (ADC, AE, and VE) before and after IAT as well as change in tumor ADC, AE, or VE had better interobserver agreement (ICC=0.830–0.974) compared with manual ROI-based axial measurements (ICC=0.157–0.799). Semi-automated measurements of tumor volume and size in the axial plane before and after IAT had better interobserver agreement (ICC=0.854–0.996) compared with manual size measurements (ICC=0.543–0.596), and interobserver agreement for change in tumor RECIST size was also higher using semi-automated measurements (ICC=0.655) compared with manual measurements (ICC=0.169). EASL measurements of tumor enhancement in the axial plane before and after IAT ((ICC=0.758–0.809), and changes in EASL after IAT (ICC=0.653) had good interobserver agreement. ConclusionSemi-automated measurements of functional changes assessed by ADC and VE based on whole-lesion segmentation demonstrated better reproducibility than ROI-based axial measurements, or RECIST or EASL measurements.

Abstract No. 239: Magnetic resonance imaging biomarkers predicting survivals after doxorubicin drug eluting beads transarterial chemoembolization (DEB TACE) in patients with unresectable hepatocellular carcinoma (HCC)

lesion was also segmented using a semi automatic segmentation software to provide 3D volumetric ADC and 3D volumetric enhancement in hepatic arterial (HAP) and portal venous phases (PVP). AFP levels (patients with baseline AFP 200ng/mL) were also utilized for assessing response. Overall patient Survival (OS) from the date of first treatment was used as primary endpoint. Statistical analysis include kaplan-Meier survival curves and Cox proportional hazards model. Results: Overall median survival for 141 patients with HCC was 20.7 months (76 deaths, 54%). Responders survived longer than nonresponders based on EASL (HR 0.39, p 0.008), 25% increase in volumetric ADC (HR 0.39, p 0.001), 50% decrease in volumetric enhancement in PVP (HR 0.35, p 0.001) and 15% decrease in AFP (HR 0.32, p 0.003), but not based on RECIST, mRECIST, decrease in tumor volume or HAP assessed 3-4 weeks after TACE. Decrease in AFP could only be analyzed in a subset of 55 (39%) patients, since the remaining 86 (61%) patients had normal AFP levels at baseline. In Multivariate analysis 25% increase in ADC and 50% decrease in PVP more consistently predicted survival times than EASL or AFP decrease. Conclusion: Treatment response by volumetric functional ADC and CE-MR in PVP consistently predicted patient survival early (3-4 weeks) post treatment and could be used as oncologic imaging biomarkers of early treatment response, progression and survival.

Behavior of Hepatocellular Adenoma on Real-time Low-Mechanical Index Contrast-Enhanced Ultrasonography With a Second-Generation Contrast Agent

The purpose of this study was to describe the behavior of histologically proven hepatocellular adenoma (HCA) on low-mechanical index (MI) contrast-enhanced ultrasonography (CEUS). A review of the databases from 4 academic hospitals revealed 18 patients (15 female and 3 male; mean age, 40 years; range, 25-71 years) with 25 histologically proven HCA lesions who were studied with CEUS at a low MI (0.04-0.1). Twenty-four of 25 lesions (96%; 95% confidence interval [CI], 80.5%-99.3%) showed high-intensity enhancement, scored as 3 on a scale of 0 to 3, whereas only 1 lesion (4%; 95% CI, 0.7%-19.5%) was scored as 2. The time of peak enhancement ranged between 10 and 19 seconds (average, 13 seconds). All but 1 of the 25 lesions (96%; 95% CI, 80.5%-99.3%) showed early homogeneous and centripetal enhancement during the hepatic arterial phase. No portal venous phase enhancement was observed in any lesion because all showed rapid wash-out (100%; 95% CI, 86.7%-100%). Twenty lesions (80%; 95% CI, 60.9%-91.1%) were found to be isoechoic to slightly hypoechoic during the portal phase, and 19 (76%; 95% CI, 56.6%-88.5%) were isoechoic to mildly hypoechoic, whereas 7 (24%; 95% CI, 11.5%-43.4%) were hypoechoic during the late phase. Contrast-enhanced ultrasonography is an effective technique for identifying the microvascular and macrovascular characteristics of HCA. Typically, HCA shows early (10-19 seconds) and centripetal enhancement during the arterial phase and isoechogenicity or mild hypoechogenicity during the portal phase, remaining slightly hypoechoic or isoechoic during the late phase in most cases.

Spectrum of Functioning Islet Cell Tumor on Multislice Computed Tomography: Experience on 70 Patients

To review experience in preoperative detection of islet cell tumors using multislice computed tomography (MSCT) and summarize various imaging features of functioning islet cell tumors on enhanced MSCT. Seventy patients with clinical or pathological diagnosis of functioning pancreatic islet cell tumor between October 2003 and February 2007 were included in this retrospective study. Seventy-four enhanced MSCT scans in these patients were identified. All MSCT scans were interpreted by two experienced radiologists by consensus interpretation. Surgery and pathology reports were used to confirm the diagnosis, localization, and size of tumors. Totally, 73 functioning islet cell tumors including 65 benign insulinomas, 2 benign glucagonomas, 3 malignant insulinomas, and 3 malignant glucagonomas were pathologically diagnosed. Tumors in only two cases were not found by MSCT. In 67 benign lesions, 32 showed typical enhancement style, 21 showed prolonged enhancement in portal venous phase, 4 showed delayed enhancement, 4 had iso-dense enhancement with normal pancreatic parenchyma, 2 had no enhancement at all in arterial phase and portal venous phase, and 4 had inhomogeneous enhancement with necrosis or cyst-formation. Patchy or spotty calcifications were found in 3 of the 67 tumors. In 6 malignant islet cell tumors, vessel invasion (2/6) and bowel invasion (1/6) were seen. Different enhancement patterns were shown. All hepatic metastases showed hyper-enhancement during their arterial phase. Pancreatic islet cell tumor may display a wide spectrum of presentations in MSCT. Tumors with unusual appearances often present as diagnostic challenges. Non-contrast and post-contrast multiphase scans are recommended for the localization of functioning islet cell tumors.

Enhancement Patterns of Hepatocellular Carcinoma at Contrast-enhanced US: Comparison with Histologic Differentiation

To retrospectively compare the arterial and portal venous phase enhancement patterns of hepatocellular carcinoma (HCC) at contrast material-enhanced ultrasonography (US) with the degree of HCC histologic differentiation. This study was approved by the research ethics board, and informed consent was obtained. The study population included 112 consecutive patients (91 men, 21 women; aged 25-86 years) with 112 histologically proved HCCs: 23 well differentiated, 77 moderately differentiated, and 12 poorly differentiated. All underwent continuous real-time low-mechanical-index contrast-enhanced US from wash-in of contrast material to 300 seconds by using a blood-pool microbubble agent. Initial image interpretation included arterial enhancement, dysmorphic intratumor arteries, and presence and time of negative enhancement (washout). Enhancement patterns were compared with histologic differentiation by using the Fisher exact test. In the arterial phase, 97 of 112 (87%) HCCs showed hypervascularity, with a significantly higher proportion in moderately differentiated HCCs (74 of 77, 96%) when compared with well- (14 of 23, 61%; P<.001) and poorly differentiated HCC (nine of 12, 75%; P<.004). Eight of 112 (7%) were isovascular and seven (6%) were hypovascular. Dysmorphic arteries were seen in 81 (72%) HCCs. Of 97 hypervascular tumors, only 42 (43%) showed typical washout by 90 seconds. Late washout appeared in 25 (26%) HCCs in the 91-180 seconds phase and in 21 (22%) in the 181-300 seconds phase. The remaining nine showed no washout up to 300 seconds and seven (78%) were well-differentiated HCCs. Moderately differentiated HCC generally shows classic enhancement features, while well- and poorly differentiated tumors account for most atypical variations. Extended observation in the portal phase is important as late washout occurs with slightly more frequency than washout in the conventionally defined portal venous phase.

Optimization of automatic bolus tracking for timing of the arterial phase of helical liver CT.

The aim of this study was to optimize bolus tracking for timing of the arterial phase of biphasic helical liver CT and to compare optimized bolus tracking to a standard delay. One hundred fifty patients were examined with six protocols: 5- or 10-s delay after triggering at a threshold of 50 or 75 or 100 HU enhancement in the aorta at the origin of the celiac arteries after injection of 120 ml contrast material at 3 ml/s. Optimal arterial enhancement was defined as 20-30% of hepatic enhancement in portal venous phase. Another 50 patients were examined with the optimized protocol and compared to 50 gender- and age-matched patients who underwent a 25-s standard delay. A 10-s delay after the 75-HU threshold resulted in the most patients with an optimal arterial phase (p < 0.01). Thirty-one of 75 patients examined with this protocol showed optimal early liver enhancement. Bolus tracking compared with standard delay revealed only a trend for a difference (p = 0.07). The outcome of automatic bolus tracking differs depending on the protocol used; however, optimal arterial phase imaging was seen in only 41% of patients, indicating only a trend for superior timing compared with a standard delay.

Alterations in hepatic perfusion resulting from splanchnic venous luminal compromise caused by pancreatic carcinoma.

We determined whether alterations in hepatic enhancement exist on dual phase helical CT of the liver in patients with splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma. We examined the extent of hepatic enhancement on dual phase helical CT in 22 patients with pancreatic adenocarcinoma. Eleven patients had splanchnic venous luminal narrowing (flattening along at least 120 degrees of the circumference) of the superior mesenteric vein with (n = 3) or without (n = 8) portal vein involvement caused by tumor. In the remaining patients, splanchnic vasculature appeared normal. An additional 16 patients without pancreatic or hepatic abnormality who underwent dual phase helical CT served as control subjects. We compared the extent of arterial phase and portal venous phase enhancement among the three groups. The group of patients with splanchnic venous luminal compromise had significantly higher hepatic enhancement during the arterial phase (p < 0.01) and lower enhancement during the portal venous phase (p < 0.05) compared with the other two groups of patients. No significant difference in hepatic enhancement during either phase was noted between the control subjects and the patients with normal vasculature. Because hepatic enhancement correlates with perfusion, splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma likely causes decreased portal venous flow and compensatory increased hepatic arterial flow. This finding supports other evidence of a homeostatic mechanism that maintains hepatic perfusion.