Jong-Young Oh

Acoustic radiation force impulse elastography for hepatocellular carcinoma-associated radiofrequency ablation

AIM To evaluate the potential usefulness of acoustic radiation force impulse (ARFI) images for evaluation of hepatocellular carcinomas (HCC)-associated radiofrequency ablation. METHODS From January 2010 to June 2010, a total of 38 patients with HCC including recurred HCCs after RFA underwent ARFI elastography. The brightness of tumor was checked and the shear wave velocity was measured for the quantification of stiffness. According to the brightness, the tumors were classified as brighter, same color and darker compared with adjacent parenchyma. Using the same methods, 8 patients with recurred HCCs after RFA state were evaluated about the brightness compared with adjacent RFA ablation area. RESULTS In the 38 patients with HCCs, 20 (52.6%) were brighter than surrounding cirrhotic parenchyma. Another 13 (34.2%) were darker. The others (5 cases, 13.2%) were seen as the same color as the adjacent liver parenchyma. Post-RFA lesions were darker than previous tumor and surrounding parenchyma in all 38 cases. However, recurred HCCs were brighter than the treated site in all 8 cases. CONCLUSION Using ARFI technique is helpful for differential diagnosis in order to detect recurred HCCs more easily in patients with confusing status.

Initial phantom study comparing image quality in computed tomography using adaptive statistical iterative reconstruction and new adaptive statistical iterative reconstruction v.

Purpose The purpose of this study was to assess the image quality of a novel advanced iterative reconstruction (IR) method called as “adaptive statistical IR V” (ASIR-V) by comparing the image noise, contrast-to-noise ratio (CNR), and spatial resolution from those of filtered back projection (FBP) and adaptive statistical IR (ASIR) on computed tomography (CT) phantom image. Materials and Methods We performed CT scans at 5 different tube currents (50, 70, 100, 150, and 200 mA) using 3 types of CT phantoms. Scanned images were subsequently reconstructed in 7 different scan settings, such as FBP, and 3 levels of ASIR and ASIR-V (30%, 50%, and 70%). The image noise was measured in the first study using body phantom. The CNR was measured in the second study using contrast phantom and the spatial resolutions were measured in the third study using a high-resolution phantom. We compared the image noise, CNR, and spatial resolution among the 7 reconstructed image scan settings to determine whether noise reduction, high CNR, and high spatial resolution could be achieved at ASIR-V. Results At quantitative analysis of the first and second studies, it showed that the images reconstructed using ASIR-V had reduced image noise and improved CNR compared with those of FBP and ASIR (P < 0.001). At qualitative analysis of the third study, it also showed that the images reconstructed using ASIR-V had significantly improved spatial resolution than those of FBP and ASIR (P < 0.001). Conclusions Our phantom studies showed that ASIR-V provides a significant reduction in image noise and a significant improvement in CNR as well as spatial resolution. Therefore, this technique has the potential to reduce the radiation dose further without compromising image quality.

Omental infarction caused by laparoscopy-assisted gastrectomy for gastric cancer: CT findings.

AIM To investigate the computed tomography (CT) imaging features of omental infarction in patients who underwent laparoscopy-assisted gastrectomy (LAG) for gastric cancer. MATERIALS AND METHODS A retrospective study was performed on 390 patients who underwent LAG for gastric cancer. Two radiologists evaluated the CT images for the presence of omental infarction. The CT pattern was characterized at initial presentation and the evolutional changes were evaluated. The initial CT appearance of omental infarctions were categorized into the following four types: type 1 (ill-defined, heterogeneous, fat density lesion); type 2 (well-defined fat density lesion with rim enhancement); type 3 (well-defined heterogeneous lesion with fat component); and type 4 (well-defined heterogeneous lesion without a fat component). RESULTS Of the 390 patients involved, nine patients (2.3%; six male and three female with a mean age of 57 years) were diagnosed with omental infarction. Infarctions averaged 4.1 cm (range 2-7.3 cm) in diameter. Among nine patients with omental infarction, two patients had type 1 lesions, two had type 2, two had type 3, and three type 4. All infarctions became smaller and better defined with evolution. In two patients who presented with type 1 lesions on initial CT, each lesion was progressed to type 2 and type 3 on follow-up CT. In two patients with type 3 lesions on initial CT, the lesions changed to type 4 on follow-up CT. CONCLUSION An awareness of the various CT features and evolutional changes in omental infarction after LAG for gastric cancer can help ensure the correct diagnosis and to avoid misdiagnosis for omental implants.

Effect of visceral fat area on outcomes of laparoscopyassisted distal gastrectomy for gastric cancer: subgroup analysis by gender and parameters of obesity

Purpose The aim of this study was to investigate the impact of the visceral fat area (VFA) of patients with gastric cancer undergoing laparoscopic surgery on operative outcomes such as number of retrieved lymph nodes (LNs) and operative time. Methods We retrospectively reviewed the medical records and the CT scans of 597 patients with gastric cancer who underwent laparoscopy assisted distal gastrectomy (LADG) with partial omentectomy and LN dissection (>D1 plus beta). Patients were stratified by gender, VFA, and body mass index (BMI), and the clinicopathologic characteristics and operative outcomes were evaluated. Multiple linear regression analysis was used to assess the effects of VFA and BMI on the number of retrieved LNs and operative time in male and female patients. Results The mean number of retrieved LNs was significantly decreased for both male and female patients with high VFA. The operative time was significantly longer for both male and female patients with high VFA. The number of retrieved LNs had a statistically significant negative correlation with VFA in both men and women, but not with BMI. The operative time had a statistically significant positive correlation with VFA in men, whereas the operative time had a statistically significant positive correlation with BMI in women. Conclusion The preoperative VFA of male patients with gastric cancer who undergo LADG may affect the number of retrieved LNs and operative time. VFA was more useful than BMI for predicting outcomes of LADG.

Afferent Loop Syndrome After Subtotal Gastrectomy With Billroth-II Reconstruction: Etiology and Treatment

The aim of this study was to evaluate the clinical characteristics, treatment, and prognosis of afferent loop syndrome (ALS) following radical subtotal gastrectomy with B-II reconstruction in gastr...