Cheong-Il Shin

Laparoscopy-assisted pylorus-preserving gastrectomy is better than laparoscopy-assisted distal gastrectomy for middle-third early gastric cancer.

Objective:The purpose of this study is to compare the surgical, oncologic safety and the nutritional, functional benefit of laparoscopy-assisted pylorus-preserving gastrectomy (LAPPG) with laparoscopy-assisted distal gastrectomy (LADG) for middle-third early gastric cancers (EGC). Background:Of those patients with middle-third EGC, it is still difficult to determine which procedure is better between LADG and LAPPG despite alleged advantages of LAPPG. Methods:For middle-third EGC, a retrospective analysis was performed comparing those who underwent LADG and those who underwent LAPPG. To evaluate surgical and oncologic safety, clinicopathologic differences including the postoperative morbidity, the pattern of lymph node metastasis and recurrence were analyzed. Postoperative protein, albumin, quantification of abdominal fat area using abdomen computed tomography, and the incidence of postoperative gallstone were compared for the evaluation of functional advantages. Results:The overall postoperative morbidity rate was similar between LADG (n = 176) and LAPPG (n = 116). Delayed gastric emptying was less frequent in LADG than in LAPPG (1.7% vs 7.8%); however, the rates of all the other complications were significantly higher in LADG than in LAPPG (17.0% vs 7.8%). The number of examined lymph nodes and metastatic lymph nodes at each lymph node station was not significantly different and 3-year recurrence-free survival rates were also similar between LADG and LAPPG (98.8% vs 98.2%). Decreases in serum protein and albumin in postoperative 1 to 6 months and abdominal fat area in postoperative 1 year were significantly greater in LADG than in LAPPG. The 3-year cumulative incidence of gallstone was significantly higher in LADG than in LAPPG (6.5% vs 0.0%). Conclusions:For middle-third EGC, LAPPG can be considered as a better treatment option than LADG in terms of nutritional advantage and lower incidence of gallstone.

Evaluation of hepatic fibrosis using intravoxel incoherent motion in diffusion-weighted liver MRI.

Objectives To determine whether intravoxel incoherent motion (IVIM)–diffusion-weighted image (DWI)–derived parameters showed better diagnostic performance than the apparent diffusion coefficient (ADCtotal) for the evaluation of hepatic fibrosis (HF). Methods This retrospective study was approved by institutional review board, and informed consent was waived. Fifty-five patients with chronic liver disease who had undergone IVIM-DWI using 8 b-values at 3 T were included. True diffusion coefficient (Dt), pseudo-diffusion coefficient (Dp), perfusion fraction (f), and ADCtotal were calculated. Receiver operating characteristic analysis was performed for all parameters for the HF staging. Results All parameters showed a significant correlation with the HF stages (−0.31 to −0.72, P < 0.05). All parameters were significantly higher in F0 to F1 than in F4 (P < 0.05). The Dp showed better performance than the ADCtotal in differentiating significant HF (≥F2) from F0 to F1. Conclusions The IVIM-derived parameters and ADCtotal showed significant correlation with HF. The D p showed better diagnostic performance for differentiating significant HF than did ADCtotal.

Unusual Causes of Varicose Veins in the Lower Extremities: CT Venographic and Doppler US Findings

There are various causes of varicose veins in the lower extremities. Among the causes are venous insufficiency of the saphenofemoral junction, saphenopopliteal junction, or usual perforating veins. Traditionally, Doppler ultrasonography (US) has been used for evaluation of varicose veins. Sometimes, varicose veins arise from an unexpected anatomic source; in these cases, computed tomographic (CT) venography can provide an overview of the varicose veins. Doppler US with complementary CT venography is useful for determining the precise cause of varicose veins. Between November 2003 and March 2008, the authors evaluated 1350 cases of varicose veins in the lower extremities with both CT venography and Doppler US. The varicose veins were classified according to their causes; unusual causes were studied and included vulvoperineal varicosity, intraosseous perforating vein incompetence, round ligament varicosity, persistent sciatic vein incompetence, Klippel-Trenaunay syndrome, and portosystemic collateral pathways. Radiologists should be familiar with the complete range of primary causes of varicose veins in the lower extremities and with their radiologic manifestations and should recognize the complementary role of CT venography in their evaluation.

High liver fibrosis index FIB‐4 is highly predictive of hepatocellular carcinoma in chronic hepatitis B carriers

Screening for hepatocellular carcinoma (HCC) is clinically important given that its early detection has remarkable survival benefits. We investigated the possible role of FIB‐4, a recently developed noninvasive marker for liver fibrosis based on routine laboratory tests, as a clinical indicator for predicting future HCC among hepatitis B surface antigen (HBsAg) carriers. Our retrospective cohort study involved 986 Korean HBsAg carriers 40 years of age or older who visited Seoul National University Hospital for a health checkup. National medical service claims data were used to determine HCC incidence. Median follow‐up time was 5.4 years (interquartile range: 4.4 years). Adjusted for age, sex, body mass index, smoking, alcohol, and antiviral medication for hepatitis B, compared to subjects with FIB‐4 <1.25, subjects with 1.7≤ FIB‐4 <2.4 showed an adjusted hazard ratio (aHR) of 4.57 (95% confidence interval [CI]: 1.50‐13.92) and subjects with FIB‐4 ≥2.4 showed an aHR of 21.34 (95% CI: 7.73‐58.92) for HCC incidence. FIB‐4 was shown to have incremental predictive value to ultrasonographic liver cirrhosis for HCC incidence (C‐index: 0.701 vs. 0.831; P = 0.001). FIB‐4 was also better predictive of HCC incidence, compared to that of ultrasonographic liver cirrhosis (C‐index: 0.775 vs. 0.701; P = 0.040). Conclusion: High FIB‐4 is a highly predictive risk factor for HCC incidence among Korean HBsAg carriers. FIB‐4 is a promising, easily applicable, and cost‐effective clinical tool in identifying a subpopulation of HBsAg carriers who are at heightened risk. Our study needs to be replicated in larger future studies on various ethnic groups; nonetheless, our study suggests that FIB‐4 may play a valuable role in HCC screening among HBsAg carriers. (Hepatology 2015;61:1261–1268)

Prospective comparison of 3T MRI with diffusion‐weighted imaging and MDCT for the preoperative TNM staging of gastric cancer

To compare the diagnostic performance of 3T magnetic resonance imaging (MRI) with diffusion‐weighted imaging (DWI) and multidetector‐row computed tomography (MDCT) for the preoperative TNM staging of gastric cancer.

Added value of diffusion‐weighted imaging to MR cholangiopancreatography with unenhanced mr imaging for predicting malignancy or invasiveness of intraductal papillary mucinous neoplasm of the pancreas

To investigate the added value of diffusion‐weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) with unenhanced MR imaging for predicting the malignancy or invasiveness of intraductal papillary mucinous neoplasms (IPMNs).

Diagnostic Performance of Gadoxetic Acid–enhanced Liver MR Imaging in the Detection of HCCs and Allocation of Transplant Recipients on the Basis of the Milan Criteria and UNOS Guidelines: Correlation with Histopathologic Findings

PURPOSE To determine whether hepatobiliary phase ( HBP hepatobiliary phase ) imaging can improve the diagnostic performance of gadoxetic acid-enhanced liver magnetic resonance (MR) imaging in the detection of hepatocellular carcinomas ( HCC hepatocellular carcinoma s) and to investigate the accuracy of gadoxetic acid-enhanced MR imaging in the allocation of transplant recipients on the basis of the Milan criteria and United Network for Organ Sharing ( UNOS United Network for Organ Sharing ) guidelines. MATERIALS AND METHODS This retrospective study had institutional review board approval; the requirement for informed consent was waived. Between June 2008 and June 2011, 63 patients who underwent liver transplantation (LT) were included. All patients underwent a gadoxetic acid-enhanced 3.0-T MR imaging examination of the liver that included HBP hepatobiliary phase images obtained 20 minutes after contrast material administration. Two abdominal radiologists independently assessed two MR imaging data sets to detect HCC hepatocellular carcinoma s: Set 1 included unenhanced and gadoxetic acid-enhanced dynamic images, and set 2 also included HBP hepatobiliary phase images. Patients were allocated into three groups: Those who did not meet the Milan criteria, those who did meet the Milan criteria with additional priority according to UNOS United Network for Organ Sharing guidelines, and those who did meet the Milan criteria without additional priority. Diagnostic performance of each data set in depicting HCC hepatocellular carcinoma s was compared by using jackknife alternative free-response receiver operating characteristics ( JAFROC jackknife alternative free-response receiver operating characteristic s). Sensitivity and accuracy of patient allocation were compared by using generalized estimating equations. RESULTS Sixty-three HCC hepatocellular carcinoma s were found in 36 of 63 patients. Eight patients were classified as not meeting Milan criteria, 12 as meeting Milan criteria with additional priority, and 43 as meeting Milan criteria without additional priority. For the detection of HCC hepatocellular carcinoma s, reader-averaged figures of merit estimated with JAFROC jackknife alternative free-response receiver operating characteristic s were 0.761 for set 1 and 0.791 for set 2 (P < .001). Addition of HBP hepatobiliary phase images significantly improved sensitivity for the detection of HCC hepatocellular carcinoma s, particularly 1-2-cm HCC hepatocellular carcinoma s (six [20.7%] vs 13 [44.8%] of 29 [P = .008] for reader 1 and eight [27.6%] vs 12 [41.4%] of 29 [P = .041] for reader 2). Accuracy of patient allocation was 88.9% for set 1 and 92.1% for set 2 (P = .151). CONCLUSION Addition of HBP hepatobiliary phase images can significantly improve the diagnostic performance of gadoxetic acid-enhanced liver MR imaging in the detection of 1-2-cm HCC hepatocellular carcinoma s in liver transplantation candidates. In addition, gadoxetic acid-enhanced MR imaging showed 92.1% accuracy in patient allocation on the basis of the Milan criteria and UNOS United Network for Organ Sharing guidelines.

Usefulness of a Metal Artifact Reduction Algorithm for Orthopedic Implants in Abdominal CT: Phantom and Clinical Study Results

OBJECTIVE. The purpose of this study was to evaluate the usefulness of a metal artifact reduction (MAR) algorithm for orthopedic prostheses in phantom and clinical CT. MATERIALS AND METHODS. An agar phantom with two sets of spinal screws was scanned at various tube voltage (80-140 kVp) and tube current-time (34-1032 mAs) settings. The orthopedic MAR algorithm was combined with filtered back projection (FBP) or iterative reconstruction. The mean SDs in three ROIs were compared among four datasets (FBP, iterative reconstruction, FBP with orthopedic MAR, and iterative reconstruction with orthopedic MAR). For the clinical study, the mean SDs of three ROIs and 4-point scaled image quality in 52 patients with metallic orthopedic prostheses were compared between CT images acquired with and without orthopedic MAR. The presence and type of image quality improvement with orthopedic MAR and the presence of orthopedic MAR-related new artifacts were also analyzed. RESULTS. In the phantom study, the mean SD with orthopedic MAR was significantly lower than that without orthopedic MAR regardless of dose settings and reconstruction algorithms (FBP versus iterative reconstruction). The mean SD near the metallic prosthesis in 52 patients was significantly lower on CT images with orthopedic MAR (28.04 HU) than those without it (49.21 HU). Image quality regarding metallic artifact was significantly improved with orthopedic MAR (rating of 2.60 versus 1.04). Notable reduction of metallic artifacts and better depiction of abdominal organs were observed in 45 patients. Diagnostic benefit was achieved in six patients, but orthopedic MAR-related new artifacts were seen in 30 patients. CONCLUSION. Use of the orthopedic MAR algorithm significantly reduces metal artifacts in CT of both phantoms and patients and has potential for improving diagnostic performance in patients with severe metallic artifacts.

Effects of Spatial Resolution and Tube Current on Computer-aided Detection of Polyps on CT Colonographic Images: Phantom Study

PURPOSE To prospectively evaluate the effects of z-axis spatial resolution and tube current on the sensitivity of a commercially available computed tomographic (CT) colonography computer-aided diagnosis (CAD) system for polyp detection by using pig colon phantoms. MATERIALS AND METHODS Ninety-six polyps were created and analyzed in 14 pig colon phantoms. CT colonography was performed by using a 16-detector CT scanner at 0.75-mm collimation; 10, 50, 100, and 160 mAs; and a pitch of 1.5. At each milliampere-second setting, the CT images were reconstructed with a section thickness (ST) of 1.5 mm and a reconstruction increment (RI) of 1.3 mm. To evaluate the effect of z-axis spatial resolution, CT images were also reconstructed at 100 mAs with various SI and RI combinations (respectively: 1.0 and 0.7 mm, 3.0 and 2.0 mm, 3.0 and 3.0 mm, 5.0 and 5.0 mm). The phantom data were then analyzed by using a CAD program. CAD performance with different CT parameters was calculated and compared in terms of per-polyp sensitivity and number of false-positive (FP) findings per data set. RESULTS At a constant tube current of 100 mAs, the polyp detection rate was significantly higher in data sets obtained with SI and RI combinations of 1.0 and 0.7 mm, respectively (81% [78/96]), and 1.5 and 1.3 mm, respectively (75% [72/96]), than in those obtained with the three thicker ST-RI settings (27% [26/96] to 64% [61/96]) (P < .01). A similar trend was observed, regardless of polyp size or morphology. However, the number of FP findings at the 1.0 mm and 0.7 mm setting (8.9 per phantom) was also significantly greater than that at the thicker ST-RI settings (4.0-6.1 per phantom) (P < .05). At a constant z-axis spatial resolution (1.5-mm ST, 1.3-mm RI), CAD polyp detection rate and number of FP findings per phantom remained nearly constant-close to 78% (75/96) and 6.1, respectively-at various tube current settings. CONCLUSION CAD performance in polyp detection at CT colonography is highly dependent on z-axis spatial resolution. However, tube current is not an influencing factor in CAD performance at a given z-axis spatial resolution. SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/2482071025/DC1.

Clinical Application of Liver MR Imaging in Wilson’s Disease

Objective To determine whether there is a correlation between liver MR findings and the clinical manifestations and severity of liver dysfunction in patients with Wilsons disease. Materials and Methods Two radiologists retrospectively evaluated MR images of the liver in 50 patients with Wilsons disease. The Institutional Review Board approved this retrospective study and informed consent was waived. MR images were evaluated with a focus on hepatic contour abnormalities and the presence of intrahepatic nodules. By using Fishers exact test, MR findings were compared with clinical presentations (neurological and non-neurological) and hepatic dysfunction, which was categorized by the Child-Pugh classification system (A, B and C). Follow-up MR images were available for 17 patients. Results Contour abnormalities of the liver and intrahepatic nodules were observed in 31 patients (62%) and 25 patients (50%), respectively. Each MR finding showed a statistically significant difference (p < 0.05) among the three groups of Child-Pugh classifications (A, n = 36; B, n = 5; C, n = 9), except for splenomegaly (p = 0.243). The mean age of the patients with positive MR findings was higher than that of patients with negative MR findings. For patients with Child-Pugh class A (n = 36) with neurological presentation, intrahepatic nodules, surface nodularity, and gallbladder fossa widening were more common. Intrahepatic nodules were improved (n = 8, 47%), stationary (n = 5, 29%), or aggravated (n = 4, 24%) on follow-up MR images. Conclusion MR imaging demonstrates the contour abnormalities and parenchymal nodules of the liver in more than half of the patients with Wilsons disease, which correlates with the severity of hepatic dysfunction and clinical manifestations.