Faculty Bibliography

PURPOSE/OBJECTIVE:To prospectively assess and compare the measurement variability of volume and mass for pure and part-solid ground-glass nodules (GGNs) with solid portions less than or equal to 5 mm by using a commercially available volumetric software program. MATERIALS AND METHODS/METHODS:This prospective study was approved by the institutional review board. Written informed consent was obtained. From November 2011 to June 2012, 73 patients (26 men and 47 women) with 94 GGNs (>5 mm and <20 mm; 72 pure and 22 part-solid GGNs) were prospectively enrolled and underwent two consecutive computed tomographic (CT) examinations. Both the volume and mass of GGNs were measured with volumetric software by two radiologists. Intraobserver, interobserver, and interscan variability were analyzed and compared by using the Bland-Altman method and coefficients of variation. The influence of the solid portion of GGNs and GGN size on interscan variability was investigated with multiple linear regression analysis and analysis of variance. RESULTS:Nodule segmentation was successful in 420 of 438 (95.9%) segmentations. As for volume measurement, interscan variability ranged from -17.3% to 18.5%, while intraobserver and interobserver variability ranged from -7.6% to 8.5% and from -11.7% to 18.1%, respectively. Interscan variability in mass measurement ranged from -17.7% to 18.6%, while intraobserver and interobserver variability ranged from -8.4% to 9.4% and from -17.5% to 11.8%, respectively. In the coefficient of variation comparison, there were no significant differences in volume and mass measurements for intraobserver, interscan, and interobserver variability. Measurement variability of volume and mass was not significantly influenced by the presence of a solid portion, solid portion size, or GGN size. CONCLUSION/CONCLUSIONS:Mass measurement of GGNs showed measurement variability from -17.7% to 18.6% and may be a useful method in the follow-up of GGNs with solid portions less than or equal to 5 mm.

OBJECTIVE:The purpose of this article is to assess the usefulness of segmental enhancement inversion on biphasic MDCT in differentiating small (<4 cm) renal oncocytomas from chromophobe renal cell carcinomas (CRCCs). MATERIALS AND METHODS/METHODS:Eighty-two patients (40 men and 42 women) with a mean (±SD) age of 54±12 years (range, 21-75 years) with 27 renal oncocytomas and 55 CRCCs diagnosed by surgery who underwent contrast-enhanced biphasic CT between January 2000 and December 2011 were included. CT scans were interpreted by two radiologists who were blinded to the pathologic findings. The tumors were evaluated for size and segmental enhancement inversion. After independent evaluation, a consensus was reached by measuring the attenuation. Pathologic analysis determined the presence of fibrous septa, cystic change, hemorrhage, and necrosis. The Fisher exact test was used to evaluate the relationship between segmental enhancement inversion, tumor type, and specific pathologic changes. Interobserver concordance was evaluated with kappa statistics. RESULTS:There were no significant differences in size between renal oncocytomas and CRCCs (p=0.458). Segmental enhancement inversion was present in 23, 20, and 21 (25.6%) of the 82 tumors according to reader 1, reader 2, and the consensus, respectively. The agreement was almost perfect (κ=0.843; p<0.001). Segmental enhancement inversion was more common in renal oncocytomas (63% [17/27]) than in CRCCs (7.3% [4/55]; p<0.001). There were no significant relationships between the four pathologic changes and tumor type or segmental enhancement inversion (p=0.351 and p=0.126, respectively). CONCLUSION/CONCLUSIONS:Our study findings suggest that segmental enhancement inversion on biphasic MDCT may be useful in differentiating small renal oncocytomas from CRCCs.

PURPOSE/OBJECTIVE:To prospectively assess the safety and mid-term therapeutic effectiveness of monopolar radiofrequency (RF) ablation with a multiple-electrode switching system for treating small- and medium-sized (≤ 5 cm) hepatocellular carcinomas (HCCs). MATERIALS AND METHODS/METHODS:The institutional review board approved this prospective study, and all patients gave informed consent. From February 2009 to January 2010, 166 patients (110 men and 56 women; age range, 38-86 years; mean age, 62 years ± 10 [standard deviation]) with 166 HCCs less than or equal to 5 cm in diameter were treated with monopolar RF ablation with a multiple-electrode switching system. One of three experienced radiologists performed the RF ablation. Technique effectiveness, ablation volume and time, and major complications were evaluated by means of computed tomography (CT) immediately after RF ablation and at follow-up CT examinations at 1 month and then every 3 months after the procedure. The overall survival, disease-free survival, and local tumor progression-free survival rates were evaluated by using the Kaplan-Meier method. RESULTS:The technique effectiveness rate determined 1 month after RF ablation was 99.4%. Mean ablation parameters were as follows: volume, 85 cm(3) ± 54; maximum diameter, 61 mm ± 13; and minimum diameter, 43 mm ± 11. The major complication rate was 4.8%. The 6-month and 1-, 2-, and 3-year local tumor progression rates were 2%, 6%, 10%, and 11%, respectively. The overall survival rates at 1, 2, and 3 years after RF ablation were 99%, 97%, and 96%, and corresponding local tumor progression-free survival rates were 94%, 90%, and 89%, respectively. The disease-free survival rates at 1, 2, and 3 years after RF ablation were 75%, 60%, and 54%, respectively. CONCLUSION/CONCLUSIONS:Monopolar RF ablation with a multiple-electrode switching system in small- and medium-sized HCCs was safe and efficient, and it provided successful local tumor control and high local tumor progression-free survival rates because an adequate ablation volume was obtained.

OBJECTIVE:The purpose of this study was to clarify the frequency of and risk factors for liver abscess formation after transarterial chemoembolization (TACE) in patients with hepatocellular carcinoma or metastatic hepatic tumors after undergoing bilioenteric anastomosis. MATERIALS AND METHODS/METHODS:From January 1996 to June 2012, 25 patients (21 men, four women; age range, 34-74 years) with hepatocellular carcinoma (n = 12) or metastatic hepatic tumors (n = 13) with an underlying bilioenteric anastomosis underwent 65 TACE procedures. The incidence of liver abscess, predisposing factors (diabetes, Child-Pugh class, leukopenia, tumor number, tumor size, tumor burden, tumor type, portal vein thrombus, lipiodol dose, particulate embolization, embolization selectivity, oily portogram, antibiotic prophylaxis, and occurrence of liver abscess at initial TACE), and clinical outcome were evaluated. Statistical analysis for relations between liver abscess and predisposing factors was performed by Fisher exact test and linear-by-linear association. RESULTS:Liver abscess developed after 17 of 65 (26.2%) TACE procedures performed on 12 of 25 (48%) patients. Two patients died of progression of liver abscess into sepsis. Univariate and multivariate analyses showed that leukopenia (p = 0.029), occurrence of liver abscess at initial TACE (p = 0.082), and particulate embolization or oily portogram (grade 2) (p = 0.001) were associated with a higher incidence of liver abscess. CONCLUSION/CONCLUSIONS:The incidence of liver abscess was high among patients with bilioenteric anastomoses who underwent TACE. Leukopenia, occurrence of liver abscess at initial session of TACE, and particulate embolization or oily portogram (grade 2) were associated with the development of liver abscess.

OBJECTIVE:The purpose of this study was to retrospectively assess the prevalence of segmental enhancement inversion of small renal oncocytomas according to tumor size. MATERIALS AND METHODS/METHODS:Thirty-three patients (19 men, 14 women; mean age, 61 years; range, 40-74 years) with 33 oncocytomas diagnosed at surgical resection who had undergone contrast-enhanced biphasic CT between January 2000 and December 2011 were included. CT scans were analyzed by two radiologists blinded to the specifics of the pathology report for size, presence of segmental enhancement inversion, enhancement pattern, and homogeneity. Segmental enhancement inversion was present when a renal mass was divided into two differently enhanced segments in the corticomedullary phase (30-40 seconds after contrast injection) with the degree of enhancement reversed in the nephrographic phase (120-180 seconds after contrast injection). The masses were further assessed for fibrous septa, cystic change, hemorrhage, and necrosis. For statistical analysis, the Pearson chi-square test and linear regression were used to evaluate the relation between the prevalence of segmental enhancement inversion and tumor size or pathologic changes. RESULTS:The mean diameter of 33 renal oncocytomas was 2.65 cm (range, 0.8-4.8 cm). There was no significant linear trend according to size (p = 0.762), although segmental enhancement inversion was significantly (p = 0.006) more common (10/12) in tumors measuring 1.5-2.9 cm. Pathologic change was present in 14 oncocytomas. There was no significant linear trend according to size (p = 0.068), but 2.5-cm and larger tumors had a significantly higher prevalence (57.9%) (p = 0.036). Segmental enhancement inversion was more common (13/19) in tumors without pathologic change (p = 0.024). CONCLUSION/CONCLUSIONS:Segmental enhancement inversion was a characteristic finding in our series of small renal oncocytomas and was more common in tumors measuring 1.5-2.9 cm. Pathologic changes such as central scar were more common in oncocytomas larger than 2.5 cm and may be related to the low occurrence of segmental enhancement inversion.

OBJECTIVE:We aimed to investigate the biological significance of signal transducers and activators of transcription 3 (STAT3) in gastric carcinoma. METHODS:Immunohistochemistry was performed on tissue array slides containing 285 gastric carcinoma specimens. The relationship between the nuclear expression of phospho-Tyr705-STAT3 (pSTAT3), an active form of STAT3, and prognosis, clinicopathological factors, proliferation, cell cycle regulators, apoptosis regulators, or angiogenesis-related proteins was evaluated. RESULTS:In nonneoplastic gastric mucosa, pSTAT3 was observed primarily in the nuclei of cells in the proliferative zone and intestinal metaplasia. In gastric carcinomas, nuclear STAT3 activation was observed in 36% of cases and was positively correlated with the Ki-67 labeling index and earlier tumor stage, whereas it was inversely correlated with lymphatic metastasis and distant metastasis (p< 0.05). Moreover, survival analyses showed that pSTAT3 expression was an independent prognostic factor of good survival. In addition, the expression of nuclear pSTAT3 positively correlated with that of cyclin D1, p21, p27, hypoxia-inducible factor-1α, or vascular endothelial growth factor (p< 0.05). CONCLUSIONS:STAT3 activation is an early event in gastric tumorigenesis and significantly correlates with better prognosis, proliferation and angiogenesis. Thus, STAT3 activation may be a valuable prognostic variable and therapeutic target in gastric carcinoma.