Clinical usefulness of free-breathing navigator-triggered 3D MRCP in non-cooperative patients: comparison with conventional breath-hold 2D MRCP

Purpose

To assess the clinical usefulness of free-breathing 3D MRCP in non-cooperative patients compared conventional breath-hold 2D MRCP.

Materials and methods

We performed FB navigator-triggered 3D MRCP using prospective acquisition correction and BH 2D MRCP in 48 consecutive, non-cooperative patients among 772 patients. Thirteen patients had malignant obstruction. Two radiologists independently graded the likelihood of a malignant obstruction, the overall image quality, and the visibility of ten, individual anatomic segments of both the biliary and pancreatic duct in each sequence. The area under the ROC curve and the repeated measures analyses of variance with multiple comparisons were used for the comparison. The κ statistics were used for interobserver agreement.

Result

The diagnostic performance for detecting malignancy was significantly higher on FB MRCP (A_z = 0.962) than on either BH SS-RARE (A_z = 0.820, P < 0.0185) or MS-HASTE MRCP (A_z = 0.816, P < 0.0067). Interobserver agreement was excellent for FB MRCP (κ = 0.889) and fair for both BH SS-RARE (κ = 0.578) and MS-HASTE MRCP (κ = 0.49). FB MRCP had a significantly higher technical quality than BH MRCP (P < 0.001). FB MRCP was seen to have statistically better visibility of peripheral IHD, right main IHD, CHD, cystic duct, and CBD than BH MRCP (P < 0.001). FB MRCP and BH SS-RARE MRCP had statistically better visibility of both the left main IHD and pancreatic duct than did BH MS-HASTE MRCP (P < 0.001).

Conclusion

FB 3D MRCP is useful for non-cooperative patients in whom conventional BH 2D methods cannot be used successfully.     

Pancreaticobiliary duct changes of periampullary carcinomas: quantitative analysis at MR imaging

Purpose

To quantitatively analyse the pancreaticobiliary duct changes of periampullary carcinomas with volumetric interpolated breath-hold examination (VIBE) and true fast imaging with steady-state precession (true FISP) sequence, and investigate the value of these findings in differentiation and preoperative evaluation.

Materials and methods

Magnetic resonance (MR) images of 71 cases of periampullary carcinomas (34 cases of pancreatic head carcinoma, 16 cases of intrapancreatic bile duct carcinoma and 21 cases of ampullary carcinoma) confirmed histopathologically were analysed. The maximum diameter of the common bile duct (CBD) and main pancreatic duct (MPD), dilated pancreaticobiliary duct angle and the distance from the end of the proximal dilated pancreaticobiliary duct to the major papilla were measured. Analysis of variance and the Chi-squared test were performed.

Results

These findings showed significant differences among the three subtypes: the distance from the end of proximal dilated pancreaticobiliary duct to the major papilla and pancreaticobiliary duct angle. The distance and the pancreaticobiliary duct angle were least for ampullary carcinoma among the three subtypes. The percentage of dilated CBD was 94.1%, 93.8%, and 100% for pancreatic head carcinoma, intrapancreatic bile duct carcinoma and ampullary carcinoma, respectively. And that for the dilated MPD was 58.8%, 43.8%, and 42.9%, respectively.

Conclusion

Quantitative analysis of the pancreaticobiliary ductal system can provide accurate and objective assessment of the pancreaticobiliary duct changes. Although benefit in differential diagnosis is limited, these findings are valuable in preoperative evaluation for both radical resection and palliative surgery.     

Inaccurate preoperative imaging assessment on biliary anatomy not increases biliary complications after living donor liver transplantation

Backgrounds and aims

Accurate assessment of graft bile duct is important to plan surgical procedure. Magnetic resonance cholangiopancreatography (MRCP) has become an important diagnostic procedure in evaluation of pancreaticobiliary ductal abnormalities and has been reported as highly accurate. We aim to estimate the efficacy of preoperative MRCP on depicting biliary anatomy in living donor liver transplantation (LDLT), and to determine whether inaccurate preoperative imaging assessment would increase the biliary complications after LDLT.

Methods

The data of 118 cases LDLT were recorded. Information from preoperative MRCP was assessed using intraoperative cholangiography (IOC) as the gold standard. The possible risk factors of recipient biliary complications were analyzed.

Results

Of 118 donors, 84 had normal anatomy (type A) and 34 had anatomic variants (19 cases of type B, 9 cases of type C, 1 case of type E, 2 cases of type F and 3 cases of type I) confirmed by IOC. MRCP correctly predicted all 84 normal cases and 17 of 34 variant cases, and showed an accuracy of 85.6% (101/118). The incidence of biliary complications was comparable between cases with accurate and inaccurate classification of biliary tree from MRCP, and between cases with normal and variant anatomy of bile duct. While cases with graft duct opening ≤5 mm showed a significant higher incidence of total biliary complications (21.1% vs. 6.6%, P = 0.028) and biliary stricture (10.5% vs. 1.6%, P = 0.041) compared with cases with large duct opening >5 mm.

Conclusion

MRCP could correctly predict normal but not variant biliary anatomy. Inaccurate assessment of biliary anatomy from MRCP not increases the rate of biliary complications, while small-sized graft duct may cause an increase in biliary complications particularly biliary stricture after LDLT.     

High spatial resolution 3D MR cholangiography with high sampling efficiency technique (SPACE): comparison of 3T vs. 1.5T

Purpose

The aim of this study was to evaluate image quality of 3D MR cholangiography (MRC) using high sampling efficiency technique (SPACE) at 3 T compared with 1.5 T.

Methods and materials

An IRB approved prospective study was performed with 17 healthy volunteers using both 3 and 1.5 T MR scanners. MRC images were obtained with free-breathing navigator-triggered 3D T2-weighted turbo spin-echo sequence with SPACE (TR, >2700 ms; TE, 780 ms at 3 T and 801 ms at 1.5 T; echo-train length, 121; voxel size, 1.1 mm × 1.0 mm × 0.84 mm). The common bile duct (CBD) to liver contrast-to-noise ratios (CNRs) were compared between 3 and 1.5 T. A five-point scale was used to compare overall image quality and visualization of the third branches of bile duct (B2, B6, and B8). The depiction of cystic duct insertion and the highest order of bile duct visible were also compared. The results were compared using the Wilcoxon signed-ranks test.

Results

CNR between the CBD and liver was significantly higher at 3 T than 1.5 T (p = 0.0006). MRC at 3 T showed a significantly higher overall image quality (p = 0.0215) and clearer visualization of B2 (p = 0.0183) and B6 (p = 0.0106) than at 1.5 T. In all analyses of duct visibility, 3 T showed higher scores than 1.5 T.

Conclusion

3 T MRC using SPACE offered better image quality than 1.5 T. SPACE technique facilitated high-resolution 3D MRC with excellent image quality at 3 T.     

Imaging features of portal biliopathy: frequency of involvement patterns with emphasis on MRCP

Purpose

To investigate the imaging features of portal biliopathy with emphasis on MR cholangiopancreatography (MRCP). The ancillary vascular findings of portal biliopathy were also evaluated by accompanying MR portography, dynamic contrast-enhanced (CE) CT, and dynamic CE MRI studies.

Materials and methods

Sixteen patients with portal cavernoma were included in the study. Patients had undergone MRCP (n = 16) studies accompanied by MR portography (n = 13), dynamic CE CT (n = 3) or dynamic CE MRI (n = 2) of the liver. Two patients had undergone both dynamic CE CT and dynamic CE MRI. Two radiologists evaluated all the examinations together, retrospectively. MRCP images were analyzed for the presence of biliary stenosis, upstream (prestenotic) dilatation, wavy appearance of the bile ducts, angulation of the common bile duct (CBD), and choledocholithiasis. MR portography, dynamic CE CT and dynamic CE MRI studies were evaluated for the existence of portal cavernomas, and the presence of gall bladder/choledochal varices.

Results

All patients had signs of portal biliopathy on MRCP. Frequencies of the biliary findings on MRCP were as follows: biliary stenosis, 93.7%; upstream dilatation, 68.7%; wavy appearance of the biliary tree, 87.5%; angulation of the CBD, 75%. None of the patients had choledocholithiasis. Frequencies of the ancillary vascular findings detected on CE studies were as follows: gall bladder varices, 100%, choledochal varices, 93.7%.

Conclusion

MRCP features of portal biliopathy in order to their frequencies were as follows: biliary stenosis, wavy appearance of the bile ducts, angulation of the CBD, and upstream dilatation of the bile ducts.     

Biliary anatomy in potential right hepatic lobe living donor liver transplantation (LDLT): the utility of CT cholangiography in the setting of inconclusive MRCP

Objective

To determine the utility of CT cholangiography (CT-Ch) in preoperative evaluation of the biliary anatomy of living-donor liver transplantation (LDLT) donors when magnetic resonance cholangiopancreatography (MRCP) is inconclusive.

Materials and methods

Over a 2-year period, 22 potential living liver donors underwent contrast-enhanced CT-Ch for preoperative evaluating biliary anatomy due to inconclusive results on MRCP and subsequently donated their right hepatic lobe. Nineteen of them underwent intraoperative cholangiography and were included in this study. Two radiologists retrospectively reviewed both MRCP and CT-Ch with 1-month interval and documented the types of bile duct branching patterns and visualization score of intrahepatic bile ducts (4-point scale).

Results

There were no complications associated with CT-Ch examinations. CT-Ch was concordant with the reference standard in 18/19 (95%) including 7/8 typical branching type and 11/11 anomalous branching types. MRCP was concordant with the reference standard in 14/19 (74%) including 4/8 typical branching types and 10/11 anomalous branching types. The discordant case by CT-Ch was the identification of a tiny accessory right intrahepatic duct joining the common bile duct which was not visualized on intraoperative cholangiography. CT-Ch showed higher visualization score (mean, 3.9) than MRCP (mean, 2.6) (P < .001).

Conclusion

CT-Ch can be effectively used for the depiction of the branching pattern of the bile duct at the hepatic hilum when MRCP is inconclusive.     

Diagnostic accuracy of MR sialography in sialolithiasis and salivary ductal stenosis

Objectives

The purpose of this study is to determine the diagnostic accuracy of MR sialography in the examination of patients with salivary duct disease.

Patients and methods

Twenty-eight patients (twenty males and eight females, average age, 47 years), with symptoms related to the salivary glands, underwent both conventional sialography and MR sialography. The latter was performed using heavily T2-weighted, two dimensional, fast spin-echo techniques and a neck coil. Contiguous 3-mm axial images with frequency-selective fat suppression were acquired through the symptomatic gland. The MR sialography findings were compared with the final diagnoses determined by conventional sialography, and with surgery in the case of those who underwent surgical intervention. Ultrasound examination was performed using 7.5 MHz transducer. Conventional sialography was performed with the use of 0.012–0.021 inch sialographic catheter and an injection of 0.3–1.5 ml Ultravist 300 mg/ml.

Results

Final diagnosis included sialolithiasis in eleven cases, sialolithiasis and stenosis in four cases, stenosis without lithiasis in ten cases and normal salivary glands in three cases. (The normal cases were excluded from the study).

Conclusion

It is concluded that MR sialography with a heavily T2-weighted sequence is highly successful in the noninvasive visualization of the ductal system of major salivary glands in cases that could not be examined by conventional sialogram. It is useful for diagnosing sialolithiasis and ductal stenosis. However, normal MR sialographic findings do not allow the exclusion of small calculi. Thus in patients with strong clinical suspicion of calculi and normal MR sialographic findings, conventional sialography should still be performed.     

The added value of diffusion-weighted MR imaging to MR cholangiopancreatography in differentiating malignant from benign extrahepatic biliary strictures

Purpose

To investigate the added value of diffusion-weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) in differentiating benign from malignant extrahepatic biliary strictures.

Methods

Magnetic resonance examination including, T2-weighted imaging, MRCP and DWI using different b-values (0,500,800 s/mm²) were performed in 38 patients with suspicious extrahepatic biliary strictures. Apparent diffusion coefficient (ADC) value was calculated. The signal intensity of the lesions on DWI using b = 500 and 800 s/mm² was examined. Analysis of the DWI and MRCP images for the cause of the extrahepatic biliary stricutre was performed. Patients were further confirmed by histopathological diagnosis and follow up. Sensitivity, specificity, accuracy, positive predictive and negative predictive values were calculated for both the MRCP images and DWI.

Results

Of the 38 cases, 23 cases had malignant extrahepatic biliary strictures and 15 had benign strictures. DWI detected 21 out of the 23 malignant biliary strictures and 14 out of 15 benign biliary strictures. Malignant strictures more frequently appeared hyperintense than benign strictures on DWI using b-values of 500 and 800 s/mm². There was a significant difference in sensitivity (91.3% vs. 73%), specificity (93.3% vs. 64.7%), accuracy (92.1% vs. 73.6%), positive predictive value (95.4% vs. 81%), and negative predictive value (87.5% vs. 64.7%) between DWI and MRCP in differentiating biliary strictures.

Conclusion

Combined evaluation using DWI added to MRCP improves the differentiation of malignant from benign extrahepatic biliary strictures.     

Characterization and staging of central bile duct stenosis—Evaluation of the hepatocyte specific contrast agent gadoxetate disodium

Objective

To assess the value of gadoxetate disodium for characterization and staging of central bile duct stenosis (CBDS).

Materials and methods

This prospective HIPAA-compliant study was IRB approved. 14 patients (8 male, 6 female; 36–80 years) with clinical suspicion of CBDS underwent preoperative MRI. To estimate the value of hepatocyte phase images (10, 20, 120 min p.i.), only T2w images (T2), only post-contrast images (CM), or both image datasets were assessed in three reading sessions by 3 readers. Agreement of each reading session with the intraoperative findings in terms of CBDS etiology and tumor extension (weighted kappa statistic) was calculated.

Results

CBDS was caused by hilar cholangiocarcinoma (n = 9), gallbladder carcinoma (n = 4) and pancreatic carcinoma (n = 1). Characterization of CBDS etiology was correct by use of: T2w images in 57%, 64%, 50%; CM images in 64%, 57%, 50%; both in 71%, 64%, 64%. Agreement comparing reading sessions and intraoperative findings regarding tumor extension was fair up to moderate (κ-range = 0.21–0.54) as a result of common underestimation. Interobserver agreement for tumor extension was fair (κ-range = 0.31–0.33).

Conclusions

By means of combined evaluation of T2 and CM images a more reliable characterization of CBDS was possible. Even though CBDS tended to be underestimated assessment of exact tumor extension was improved by contrast administration.     

Usefulness of free-breathing readout-segmented echo-planar imaging (RESOLVE) for detection of malignant liver tumors: Comparison with single-shot echo-planar imaging (SS-EPI)

Purpose

We aimed to clarify the usefulness of free-breathing readout-segmented echo-planar imaging (RESOLVE), which is multi-shot echo-planar imaging based on a 2D-navigator-based reacquisition technique, for detecting malignant liver tumor.

Materials and methods

In 77 patients with malignant liver tumors, free-breathing RESOLVE and respiratory-triggered single-shot echo-planar imaging (SS-EPI) at 3-T MR unit were performed. We set a scan time up to approximately 5 min (300 s) before examination, measured actual scan time and assessed (1) susceptibility and (2) motion artifacts in the right and left liver lobes (3, no artifact; 1, marked), and (3) detectability of malignant liver tumors (3, good; 1, poor) using a 3-point scale.

Results

The median actual scan time of RESOLVE/SS-EPI was 365/423 s. The median scores of each factor in RESOLVE/SS-EPI were as following in this order: (1) 3/2 (right lobe); 3/3 (left lobe), (2) 2/3 (right lobe); 1/2 (left lobe), and (3) 3/3, respectively. Significant differences were noted between RESOLVE and SS-EPI in all evaluated factors (P < 0.05) except for susceptibility of left lobe and detectability of the lesions.

Conclusion

Despite the effect of motion artifacts, RESOLVE provides a comparable detectability of the lesion and the advantage of reducing scanning time compared with SS-EPI.     

Underestimation of invasive lesions in patients with ductal carcinoma in situ of the breast diagnosed by ultrasound-guided biopsy: A comparison between patients with and without HER2/neu overexpression

Purpose

To determine the rate of underestimation of ductal carcinoma in situ (DCIS) diagnosed at imaging-guided biopsy and to analyze its association with HER2/neu oncogene, an important biomarker in assessing the tumour aggressiveness and guiding hormone therapy for breast cancer.

Methods

We retrospectively reviewed 162 patients with DCIS diagnosed by imaging-guided core needle biopsy between January 2008 and March 2013. All of these patients received surgical excision, and in 25, the diagnosis was upgraded to invasive breast cancer. In this study, we examined the ultrasound, mammographic features and histopathological results for each patient, and compared these parameters between those with and without HER2/neu overexpression.

Results

Of the 162 DCIS lesions, 110 (67.9%) overexpressed HER2/neu. Nineteen patients with HER2/neu overexpressing DCIS (n = 19/110, 17.3%) were upgraded after surgery to a diagnosis of invasive breast cancer. In this group, the upgrade rate was highest in patients with a dilated mammary duct pattern (42.1%, n = 8/19, p = 0.02) and the presence of abnormal axillary nodes (40.0%, n = 12/30, p < 0.01) at ultrasound and was significantly associated with comedo tumour type on pathology.

Conclusions

Biopsy may underestimate the invasive component in DCIS patients. Sonographic findings of dilated mammary ducts and presence of abnormal axillary lymph nodes may help predicting the invasive components and possibly driving more targeted biopsy procedures.     

Hepatobiliary transit times of gadoxetate disodium (Primovist) for protocol optimization of comprehensive MR imaging of the biliary system—What is normal?

Objective

The purpose of this study was to determine transit times for excretion of Gd-EOB-DTPA into different segments of the hepatobiliary system in patients with normal liver function.

Methods

This retrospective study was IRB approved with a waiver of consent granted. 61 patients (39 female, 22 male, mean age 52.5 years) with normal liver and renal function who underwent contrast enhanced hepatic MRI after injection of 10 mLGd-EOB-DTPA at 1.5 T and 3 T were included. Two readers evaluated all delayed images (3-20 min post contrast) for the presence of contrast agent in the intrahepatic bile ducts (IBD), the common bile duct (CBD), the gallbladder and the duodenum. A two-tailed, unpaired Student's t-test with p < 0.05 deemed significant was used to determine whether transit times were affected by patient gender, age or body mass index.

Results

20 min after contrast initiation, Gd-EOB-DTPA could be detected in the IBD and the CBD in all patients (100%); gallbladder reflux was visible in 53 (86.9%), duodenal excretion in 40 patients (65.5%), respectively. Mean transit times for contrast appearance in the various segments were as follows: IBD 12 min 13 s; CBD 12 min 27 s; gallbladder 13 min 32 s. Transit times were not significantly affected by patient gender, age or BMI.

Conclusion

Within 20 min post contrast initiation, Gd-EOB-DTPA can be expected in the IBD and the CBD in patients with normal liver function. However, functional information about the sphincter Oddi complex can be ascertained only in about two thirds of these patients within this timeframe.     

An increased flip angle in late phase Gd-EOB-DTPA MRI shows improved performance in bile duct visualization compared to T2w-MRCP

Objectives

To estimate the additional value of an increased flip angle of 35° in late phase Gd-EOB-DTPA-enhanced magnetic resonance cholangiography, as compared to T2w-MRCP.

Methods

40 adult patients underwent Gd-EOB-DTPA enhanced MRI of the liver including a T2-weighted 3D TSE MRCP (T2w-MRCP) as well as a late phase T1-weighted THRIVE sequences applying a flip angle of 35° (fa35). Two experienced observers evaluated the images regarding the delineation of the different biliary regions using a three-point grading system. A five-point scale was applied to determine the readers’ confidence in identifying anatomical variations of the biliary tree. ROI analysis was performed to compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios.

Results

The quality for visualizing the biliary tree differed between T2w-MRCP and fa35 (p = <0.001). Late phase EOB-MRC was rated as good for delineating the entire biliary system, whereas T2w-MRCP received an overall poor rating. Especially the depiction of the intrahepatic bile ducts was estimated as problematic in T2w-MRCP. T2w-MRCP and fa35 revealed a discordant assessment of anatomical variations in 12.5% of the cases, comprising a generally higher confidence level for fa35 (4.0 ± 1.1 vs. 2.2 ± 1.2, p = <0.001). SNR proofed to be significantly higher in fa35 (p = <0.001), whereas T2w-MRCP revealed a significantly higher CNR (<0.001).

Conclusions

Gd-EOB-DTPA enhanced magnetic resonance cholangiography acquired with a flip angle of 35° revealed a better diagnostic performance compared to T2w-MRCP and might be a valuable adjunct in assessing functional bile duct abnormalities.     

Clinical application of qualitative assessment for breast masses in shear-wave elastography

Purpose

To evaluate the interobserver agreement and the diagnostic performance of various qualitative features in shear-wave elastography (SWE) for breast masses.

Materials and methods

A total of 153 breast lesions in 152 women who underwent B-mode ultrasound and SWE before biopsy were included. Qualitative analysis in SWE was performed using two different classifications: E values (Ecol; 6-point color score, Ehomo; homogeneity score and Esha; shape score) and a four-color pattern classification. Two radiologists reviewed five data sets: B-mode ultrasound, SWE, and combination of both for E values and four-color pattern. The BI-RADS categories were assessed B-mode and combined sets. Interobserver agreement was assessed using weighted κ statistics. Areas under the receiver operating characteristic curve (AUC), sensitivity, and specificity were analyzed.

Results

Interobserver agreement was substantial for Ecol (κ = 0.79), Ehomo (κ = 0.77) and four-color pattern (κ = 0.64), and moderate for Esha (κ = 0.56). Better-performing qualitative features were Ecol and four-color pattern (AUCs, 0.932 and 0.925) compared with Ehomo and Esha (AUCs, 0.857 and 0.864; P < 0.05). The diagnostic performance of B-mode ultrasound (AUC, 0.950) was not significantly different from combined sets with E value and with four color pattern (AUCs, 0.962 and 0.954). When all qualitative values were negative, leading to downgrade the BI-RADS category, the specificity increased significantly from 16.5% to 56.1% (E value) and 57.0% (four-color pattern) (P < 0.001) without improvement in sensitivity.

Conclusion

The qualitative SWE features were highly reproducible and showed good diagnostic performance in suspicious breast masses. Adding qualitative SWE to B-mode ultrasound increased specificity in decision making for biopsy recommendation.     

Intraductal papillary mucinous neoplasms of the pancreas: Correlation of helical CT features with pathologic findings

Objective

To evaluate the CT features of intraductal papillary mucinous neoplasms of the pancreas (IPMNs), and to compare with pathological findings in order to identify CT features that can be helpful in differentiating benign IPMNs from malignant IPMNs.

Materials and methods

The CT findings in 25 patients were reviewed for tumor location, tumor type, dilatation of the main pancreatic duct (MPD), MPD involvement, mural node or solid attenuating component, tumor size in branch duct or mixed duct type, dilatation of common bile duct (CBD) and invasion of surrounding structures. The data was subjected to Chi-Square Tests or Fisher's Exact Test using SPSS13.0 software with p value < 0.05 indicating significant statistical difference.

Results

Presence of mural node or solid enhancing component, size of mural node or solid enhancing component ≥7 mm, dilatation of CBD was more common in malignant IPMNs (p < 0.05). None of tumor location, tumor type, dilatation of MPD, MPD involvement, tumor size, and invasion of surrounding structures was statistically significant in differentiating benign from malignant IPMNs.

Conclusions

CT features suggestive of malignant or invasive IPMNs include presence of mural node or solid enhancing component, size of mural node or solid enhancing component ≥7 mm, and dilatation of CBD.     

Quantitative hepatic CT perfusion measurement: Comparison of Couinaud's hepatic segments with dual-source 128-slice CT

Purpose

To compare the quantitative liver computed tomography perfusion (CTP) differences among eight hepatic segments.

Materials and methods

This retrospective study was based on 72 acquired upper abdomen CTP scans for detecting suspected pancreas tumor. Patients with primary or metastatic liver tumor, any focal liver lesions except simple cyst (<3 cm in diameter), history of liver operation or splenectomy, evidence of liver cirrhosis or invasion of portal vein were excluded. The final analysis included 50 patients (M:F = 21:29, mean age = 43.2 years, 15–76 years). Arterial liver perfusion (ALP), portal-venous perfusion (PVP), total hepatic perfusion (THP = ALP + PVP), and hepatic perfusion index (HPI) of each hepatic segment were calculated and compared by means of one-way analysis of variance (ANOVA) and the Bonferonni correction method.

Results

Compared to hepatic segments 5, 6, 7 and 8, segments 2 and 3 showed a tendency of higher ALPs, lower PVPs, and higher HPIs, most of which were statistically significant (p < 0.05). Hepatic segments 1 and 4 had higher mean values of ALP and HPI and lower mean values of PVP than segments 5, 6, 7 and 8 as well, although no significant differences were detected except for ALP and HPI for liver segments 1 and 7 (p = 0.001 and 0.035 respectively), and ALP for liver segments 1 and 5 (p = 0.039). Higher ALP and HPI were showed in hepatic segment 3 compared to segment 4 (p = 0.000 and 0.000 respectively). No significant differences were found for THP among eight segments.

Conclusions

Intra-hepatic perfusion differences exist in normal hepatic parenchyma especially between lateral sector (segments 2 and 3) and right lobe (segments 5, 6, 7 and 8). This might have potential clinical significance in liver-perfusion-related protocol design and result analysis.     

Effect of saline flush on enhancement of proximal and distal segments using 320-row coronary CT angiography

Objective

To investigate the effect of saline flush on coronary CT angiography of proximal, middle, and distal coronary artery segments, using 320-row CT, and to compare two injection duration protocols as to amount of contrast in the right heart chambers.

Methods

This retrospective study was approved by the local ethics committee, and the requirement for informed consent to participate in this study was waived. The final study group included 108 patients who underwent coronary CT angiography. The first 36 patients received contrast medium without saline flush (group 1); the next 36 patients received contrast medium for 14 s and saline flush (group 2); the last 36 patients received contrast medium for 12 s and saline flush (group 3). The CT number, noise, contrast-to-noise ratio (CNR), and number of segments with a CT number greater than 325 Hounsfield units (HU) were recorded for proximal, middle, and distal segments.

Results

The CT numbers and the CNR in groups 2 and 3 were significantly higher than that in group 1 (p < 0.005); the difference between groups 2 and 3 was not significant. The proportion of segments greater than 325 HU improved with saline flush (p < 0.05), with a larger improvement in the distal segments.

Conclusions

Saline flush improves enhancement and CNR of coronary arteries, particularly of distal segments, in coronary CT angiography using 320-row CT. An average contrast medium injection of 44 mL was feasible using a saline flush.     

Detection of suspected placental invasion by MRI: Do the results depend on observer’ experience?

Purpose

To evaluate the diagnostic value of previously described MR features used for detecting suspected placental invasion according to observers’ experience.

Materials and methods

Our population included 25 pregnant women (mean age 35.16) investigated by prenatal MRI (1.5 T, T1- and T2-weighted MR-sequences without i.v. contrast), among them 12 with histopathologically proven placental invasion and 13 women (52%) without placental invasion used as control group. Two senior and two junior radiologists blindly and independently reviewed MR-examinations in view of 6 previously defined MR-features indicating presence and degree of placental invasion (placenta increta, accreta or percreta). For each reader the sensibility, specificity, and receiver operating curve (ROC) were calculated. Interobserver agreements between senior and junior readers were determined. Stepwise logistic regression was performed including the 6 MR-features predictive of placental invasion.

Results

Demographics between both groups were statistically equivalent. Overall sensitivity and specificity for placental invasion was 90.9% and 75.0% for seniors and 81.8% and 61.8% for juniors, respectively. The best single MR-feature indicating placental invasion was T2-hypointense placental bands (r² = 0.28), followed by focally interrupted myometrial border, infiltration of pelvic organs and tenting of the bladder (r² = 0.36). Interobserver agreement for detecting placental invasion was 0.64 for seniors and 0.41 for juniors, thus substantial and moderate, respectively. Seniors detected placental invasion and depth of infiltration with significantly higher diagnostic certitude than juniors (p = 0.0002 and p = 0.0282, respectively).

Conclusion

MRI can be a reliable and reproducible tool for the detection of suspected placental invasion, but the diagnostic value significantly depends on observers’ experience.     

Contrast-enhanced CT and diffusion-weighted MR imaging: Performance as a prognostic factor in patients with pancreatic ductal adenocarcinoma

Objective

To determine whether contrast enhancement of CT and apparent diffusion coefficient on diffusion-weighted MR imaging are important parameters that can predict outcomes for patients with pancreatic ductal adenocarcinoma.

Materials and methods

Ninety-two patients with histologically confirmed pancreatic ductal adenocarcinoma who underwent quadriphasic CT (including unenhanced, pancreatic parenchymal, portal venous and delayed phases) and fat-suppressed single-shot echo-planar diffusion-weighted MR imaging at 3.0 T were retrospectively analyzed to investigate prognostic factors. Overall survival curves were drawn using the Kaplan–Meier method. Effects on survival of variables including age, sex, tumor location, tumor size, TNM stage, carbohydrate antigen 19-9, carcinoembryonic antigen, treatment, tumor contrast enhancement and apparent diffusion coefficient values were analyzed in univariate analysis using the log-rank test. Variables were analyzed in multivariate analyses using the Cox proportional hazards regression model.

Results

Median survival for the entire patient population was 18.2 months. Higher contrast enhancement during all phases was associated with significantly longer overall survival (P < 0.001 for all phases). The difference in overall survival between groups divided by median apparent diffusion coefficient value was not significant (P = 0.672). TNM stage (P = 0.026) and tumor contrast enhancement on CT (P = 0.027) were significantly related to survival in multivariate analysis.

Conclusions

Poor enhancement of pancreatic adenocarcinomas on enhanced CT is associated with reduced patient survival.     

Diagnostic value of CT features of the gallbladder in the prediction of gallstone pancreatitis

Purpose

The aim of this retrospective study was to evaluate the diagnostic value of CT features of the gallbladder in the prediction of gallstone pancreatitis.

Materials and methods

Eighty-six patients who underwent a diagnostic computed tomography (CT) scan for acute pancreatitis were included. The readers assessed the presence of pericholecystic increased attenuation of the liver parenchyma, enhancement of gallbladder (GB) and common bile duct (CBD) wall, pericholecystic fat strands, GB wall thickening, stone in the GB or CBD, and focal or diffuse manifestations of pancreatitis on abdominal CT scans. In addition, the maximal transverse luminal diameters of the GB and CBD were measured.

Results

The presence of pericholecystic increased attenuation of the liver parenchyma, GB wall enhancement and thickening, pericholecystic fat strands, stone in the GB or CBD, and diffuse manifestations of pancreatitis achieved statistical significance for differentiation of gallstone induced pancreatitis from non-biliary pancreatitis (p < 0.05). The mean values of maximal transverse luminal diameter of GB and CBD were significantly higher in gallstone induced pancreatitis group (39.67 ± 7.26 mm, 10.20 ± 4.13 mm) than non-biliary pancreatitis group (27.01 ± 6.14 mm, 3.85 ± 2.51 mm, p < 0.0001).

Conclusion

Gallbladder features of CT in patients with pancreatitis could be the valuable clues for the diagnosis of gallstone induced pancreatitis.