Soon Ho Yoon

Intrahepatic Mass-forming Cholangiocarcinomas: Enhancement Patterns at Multiphasic CT, with Special Emphasis on Arterial Enhancement Pattern—Correlation with Clinicopathologic Findings

PURPOSE To evaluate the imaging features of intrahepatic mass-forming cholangiocarcinomas (IMCCs) at computed tomography (CT), with a special emphasis on the degree and pattern of arterial enhancement, and to determine whether the clinicopathologic features of IMCCs with arterial enhancement differ from those of IMCCs with less arterial enhancement. MATERIALS AND METHODS The institutional review board of Seoul National University Hospital approved this retrospective study, and informed patient consent was waived. Sixty-four patients with 70 pathologically confirmed IMCCs after surgical resection underwent multiphasic CT-unenhanced, hepatic arterial phase (HAP), portal venous phase, and/or equilibrium phase imaging. CT images were retrospectively evaluated for tumor morphology and enhancement features. Patients were placed into typical or atypical enhancement groups according to the presence of enhancement in the largest volume (>50%) of the tumors during the HAP. Imaging features of IMCCs were correlated with pathologic features. The typical and atypical enhancement groups were compared with respect to disease-free survival and overall survival. Survival rates were calculated by using the Kaplan-Meier method, and differences in survival were compared by using the log-rank test. A Cox proportional hazards model was used for multivariate survival analysis. RESULTS Fifty (71%) of 70 IMCCs showed typical arterial enhancement, and 20 (29%) showed atypical enhancement. The mean diameter of atypical IMCCs was significantly smaller than that of typical IMCCs (P = .001). Chronic liver disease was more frequent in the group with atypical lesions (P = .021). During the HAP, the prevalent enhancement pattern in this group was a mixed pattern of peripheral rim and internal heterogeneous enhancement. At pathologic evaluation, atypically enhancing IMCCs showed less central stroma and necrosis and larger cellular areas and more frequently had a cholangiolocellular component than typically enhancing IMCCs. Arterial enhancement of IMCCs was found to be an independent prognostic factor for longer disease-free survival. CONCLUSION Arterially enhancing IMCCs were not rare; thus, enhancement pattern analysis of arterially enhancing IMCCs will be helpful in differentiating them from hepatocellular carcinomas. In addition, arterial enhancement of IMCCs appears to correlate with disease-free survival.

Imaging features to distinguish malignant and benign branch-duct type intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis.

Objective:To systematically determine the imaging findings for distinguishing malignant and benign branch-duct type intraductal papillary mucinous neoplasms (BD-IPMNs), including mixed type, and their diagnostic value through meta-analysis of published studies. Background:Management of BD-IPMNs, including mixed type, largely relies on imaging findings. The current knowledge on imaging findings to distinguish malignant and benign BD-IPMNs has weak evidence and is mostly from scattered individual retrospective studies. Methods:Thorough literature search in Ovid-MEDLINE and EMBASE databases was conducted to identify studies where findings of computed tomography, magnetic resonance imaging, and endoscopic ultrasonography of BD-IPMNs with or without main pancreatic duct (MPD) dilatation were correlated with surgical/pathological findings. Review of 1128 article candidates, including full-text review of 102 articles, identified 23 eligible articles with a total of 1373 patients for meta-analysis. Dichotomous data regarding distinction between malignant and benign BD-IPMNs were pooled using random effects model to obtain the diagnostic odds ratios (DORs) and their 95% confidence intervals (CIs) of various individual imaging findings for diagnosing malignant BD-IPMN. Results:Presence of mural nodules revealed the highest pooled DOR (95% CI) of 6.0 (4.1–8.8) followed by MPD dilatation [3.4 (2.3–5.2)], thick septum/wall [unadjusted, 3.3 (1.5–6.9); publication bias-adjusted, 2.3 (0.9–5.5)], and cyst size greater than 3 cm [2.3 (1.5–3.5)]. Multilocularity and multiplicity of the cystic lesions did not reveal statistically significant association with malignancy. Conclusions:Presence of mural nodules should be regarded highly suspicious for malignancy warranting a surgical excision whereas cyst size greater than 3 cm, MPD dilatation (5–9 mm), or thick septum/wall may better be managed by careful observation and/or further evaluation.

Multiphasic MDCT enhancement pattern of hepatocellular carcinoma smaller than 3 cm in diameter: tumor size and cellular differentiation.

OBJECTIVE The purpose of this study was to evaluate according to size and degree of cellular differentiation the multiphasic MDCT enhancement pattern of hepatocellular carcinoma (HCC) smaller than 3 cm in diameter in patients with cirrhosis. MATERIALS AND METHODS In 155 consecutively registered patients (126 men, 29 women; mean age, 58.4 years), 204 pathologically proven HCCs smaller than 3 cm were detected at multiphasic MDCT. Three radiologists in consensus classified the relative attenuation of the tumors compared with the surrounding liver parenchyma as hyperattenuation, isoattenuation, or hypoattenuation on biphasic (n = 86) and triphasic (n = 69) CT scans. RESULTS The prevalent enhancement patterns of HCC differed depending on tumor size. The prevalent pattern of HCC measuring 20-29 mm was arterial hyperattenuation with venous washout (47%, 47/101). The prevalent enhancement patterns of HCC smaller than 10 mm and HCC measuring 10-19 mm were isoattenuation during the arterial and portal venous phases (29%, 6/21) and hyperattenuation and isoattenuation during the arterial and portal venous phases (33%, 27/82). The typical HCC enhancement pattern (arterial hyperattenuation with venous washout) was identified in 48% (67/141) of the moderately and poorly differentiated HCCs and in 13% (8/63) of well-differentiated HCCs. CONCLUSION The prevalent enhancement patterns of HCC smaller than 3 cm on multiphasic MDCT scans differed depending on tumor size and cellular differentiation. HCCs smaller than 2 cm and well-differentiated HCCs frequently had atypical enhancement patterns.

Small (≤20 mm) Pancreatic Adenocarcinomas: Analysis of Enhancement Patterns and Secondary Signs with Multiphasic Multidetector CT

PURPOSE To evaluate the enhancement patterns, prevalence of secondary signs, and histopathologic features of 20-mm-diameter or smaller pancreatic cancers seen on multiphasic multidetector computed tomographic (CT) images. MATERIALS AND METHODS This retrospective study was approved by the institutional review board; the requirement for informed consent was waived. From January 2002 through September 2009, the authors reviewed the clinical and imaging data of 130 consecutive patients (76 men, 54 women; mean age, 64.1 years; age range, 28-82 years) who had surgically proven 30-mm-diameter or smaller pancreatic cancers and underwent preoperative multidetector CT and 33 consecutive patients (17 men, 16 women; mean age, 65.1 years; age range, 48-84 years) who had histopathologically proven pancreatic cancer and underwent incidental multidetector CT before the diagnosis was rendered. Only pancreatic phase CT was performed in two patients, and only hepatic venous phase CT was performed in nine patients. Two radiologists in consensus classified the tumor attenuation as hyper-, iso-, or hypoattenuation during the pancreatic and hepatic venous phases. Accompanying secondary signs, temporal changes in tumor attenuation, and histopathologic findings also were analyzed. The Fisher exact test, χ(2) test, generalized estimating equation, and Student t test were used to compare the variables. RESULTS Seventy tumors were 20 mm or smaller, and 93 were 21-30 mm. Isoattenuating pancreatic cancers were more commonly observed among the 20-mm or smaller tumors (16 of 59, 27%) than among the 21-30-mm tumors (12 of 93, 13%) (P = .033). They were also more common among well-differentiated tumors (seven of 12, 58%) than among moderately differentiated (20 of 124, 16%) and poorly differentiated (one of 10, 10%) tumors (P = .001). The prevalence of secondary signs differed significantly according to tumor size (53 [76%] of 70 ≤20-mm tumors vs 92 [99%] of 93 21-30-mm tumors) (P < .001). The prevalence of secondary signs was high among isoattenuating pancreatic cancers (14 [88%] of 16 ≤20-mm tumors vs all 12 [100%] 21-30-mm tumors). Most of the isoattenuating tumors seen at prediagnostic CT were hypoattenuating after 6 months (100% [four of four] during pancreatic phase, 71% [five of seven] during hepatic venous phase). CONCLUSION The prevalence of isoattenuating pancreatic cancers differed significantly according to tumor size and cellular differentiation. Most small isoattenuating pancreatic cancers showed secondary signs. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101133/-/DC1.

Positron Emission Tomography/Magnetic Resonance Imaging Evaluation of Lung Cancer Current Status and Future Prospects

Various designs of positron emission tomography/magnetic resonance imaging (PET/MRI) systems have been recently introduced to clinical practice, which have overcome preexisting technical challenges concerning the fusion of PET and MRI systems. Although further improvements are still necessary especially for bony lesions, quantification using current MRI-based attenuation correction techniques has been shown to be comparable to that of PET/computed tomography (CT) systems. On the basis of the results of previous whole-body MRI studies, PET/MRI is expected to show even better performance than PET/CT in M-staging especially for brain and liver metastases. Another advantage of PET/MRI over PET/CT, in addition to good soft tissue contrast, is the potential reduction in radiation dose. The next important hurdle to overcome for its clinical application is the development of time-efficient protocols for lung cancer evaluation and interpretation of discordant results from both modalities. Multiparametric imaging through PET/MRI will help radiologists better understand tumor biology and better evaluate treatment response.

Skin tests in patients with hypersensitivity reaction to iodinated contrast media: a meta‐analysis

Patients with a previous history of hypersensitivity reaction (HSR) to iodinated contrast media (ICM) are at high risk of the development of HSR to ICM. Many studies have tried to evaluate the diagnostic potential of skin tests in this population but have not yet reached a common conclusion. We investigated the role of skin tests in patients with HSR to ICM in terms of positive rate, cross‐reactivity rate, and tolerability to skin test‐negative ICM according to the type of HSR.

Pulmonary aspergillosis in immunocompetent patients without air-meniscus sign and underlying lung disease: CT findings and histopathologic features

Background Pulmonary aspergillosis in immunocompetent patients has been described as a saprophytic infection with pre-existing lung lesions showing an air-meniscus sign on chest radiograph or CT scans. There have been rare articles dealing with pulmonary aspergillosis in immunocompetent patients without pre-existing lung lesions. Purpose To evaluate the CT findings of pulmonary aspergillosis in immunocompetent patients without air-meniscus and underlying lung disease and to correlate the CT findings and pathologic features of pulmonary aspergillosis in these patients. Material and Methods A total of seven surgically proven pulmonary aspergillosis found in immunocompetent patients without an air-meniscus and underlying lung disease (M:F = 1:6; mean age 63.4 years) were included. On CT, the lesion shape, margin, type, location, diameter, presence of satellite nodules, presence of CT halo sign or hypodense sign, and interval growth were evaluated. Histopathologic features of each lesion were classified as one of the following; primary aspergilloma, chronic necrotizing pulmonary aspergillosis, or invasive pulmonary aspergillosis. Correlation between CT findings and pathological features was performed. Results All lesions presented as a nodule or mass unable to differentiate from malignancy. Most lesions had well-defined margins (n = 4), appeared as solid lesions (n = 7), and were located in the upper lobe (n = 5). Mean diameter of lesions was 2.3 cm. Satellite nodules (n = 2), CT halo sign (n = 1), and hypodense sign (n = 4) were found. Only one lesion increased in size during follow-up. Lesions were pathologically classified as primary aspergilloma (n = 3) and chronic necrotizing pulmonary aspergillosis (n = 4). The hypodense sign on CT was pathologically proved as dense fungal hyphae filled in bronchus and CT halo sign as parenchymal hemorrhage. Conclusion Pulmonary aspergillosis predominantly presented as a nodule or mass mimicking malignancy in the upper lobes on CT scan in elderly without underlying lung disease and immunosuppressive conditions except for age, and was histopathologically revealed to be either primary aspergilloma or chronic necrotizing pulmonary aspergillosis.

Impact of sputum gross appearance and volume on smear positivity of pulmonary tuberculosis: a prospective cohort study

BackgroundAlthough checking specimen quality upon sputum collection for acid-fast smear of suspected tuberculosis (TB) cases is recommended, this procedure is based on expert opinion. The purpose of this study was to elucidate the impact of sputum gross appearance and volume on smear positivity among patients with suspected pulmonary TB, according to sex.MethodsFrom November 2010 through June 2011, we enrolled consecutive patients suspected to have active pulmonary TB. The association of sputum gross appearance and volume with smear positivity, along with other variables possibly affecting smear positivity such as symptoms, disease extent, and cavity on chest radiograph, were investigated.ResultsAmong 2,439 patients undergoing TB examination, 170 (113 men, 57 women) with active pulmonary TB were enrolled. They submitted 492 sputa. There were 73 smear-positive patients (42.9%) and 164 smear-positive sputa (33.3%). While gross appearance was associated with smear positivity in both sexes (purulent or blood-tinged sputum (rather than mucoid sputum or saliva); odds ratio (OR), 2.05, 95% confidence interval (CI), 1.21–3.47 in men; OR, 2.78, 95% CI, 1.23–6.26 in women), the amount of sputum specimens was associated with smear positivity in only female patients (≥4 ml versus <4 ml; OR, 4.96, 95% CI, 1.98–12.37).ConclusionsSputum gross appearance and volume were associated with smear positivity. A volume of 4 ml seems to be the the minimum sputum volume acceptable for smear microscopy in females suspected of TB. Those suspected of TB should be encouraged to expectorate grossly qualified sputum specimens.

Tumor Heterogeneity in Lung Cancer: Assessment with Dynamic Contrast-enhanced MR Imaging

Purpose To evaluate histogram and texture parameters on pretreatment dynamic contrast material-enhanced (DCE) magnetic resonance (MR) images in lung cancer in terms of temporal change, optimal time for analysis, and prognostic potential. Materials and Methods This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Thirty-eight patients with pathologically proved lung cancer undergoing standard pretreatment DCE MR imaging were included. A fat-suppressed, T1-weighted, volume-interpolated breath-hold MR sequence was performed every 30 seconds for 300 and 480 seconds after contrast material administration. A region of interest was manually drawn in the largest cross-sectional area of the tumor on DCE MR images to extract semiquantitative perfusion, histogram, and texture parameters. Predictability of 2-year progression-free survival (PFS) was analyzed by using the Kaplan-Meier method and Cox regression analysis. Results MR histogram and texture parameters increased rapidly 30-60 seconds after contrast material administration. Standard deviation and entropy then plateaued, whereas skewness and kurtosis rapidly decreased. Univariate Cox regression analysis revealed that standard deviation and entropy were significant predictors of survival; their statistical significance was preserved from 60 to 300 seconds, with the smallest P values (P ≤ .001) occurring from 120 to 180 seconds. At multivariate Cox regression analysis, entropy was the sole significant predictor of 2-year PFS (hazard ratio at 180 seconds, 10.098 [95% confidence interval: 1.579, 64.577], P = .015; hazard ratio at 120 seconds: 11.202 [95% confidence interval: 1.761, 71.260], P = .010). Conclusion Histogram and texture parameter changes varied after contrast material injection. The 120-180-second window after contrast material injection was optimal for MR imaging-derived texture parameter and entropy at DCE MR imaging. (©) RSNA, 2016 Online supplemental material is available for this article.

Computer-aided classification of visual ventilation patterns in patients with chronic obstructive pulmonary disease at two-phase xenon-enhanced CT.

Objective To evaluate the technical feasibility, performance, and interobserver agreement of a computer-aided classification (CAC) system for regional ventilation at two-phase xenon-enhanced CT in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods Thirty-eight patients with COPD underwent two-phase xenon ventilation CT with resulting wash-in (WI) and wash-out (WO) xenon images. The regional ventilation in structural abnormalities was visually categorized into four patterns by consensus of two experienced radiologists who compared the xenon attenuation of structural abnormalities with that of adjacent normal parenchyma in the WI and WO images, and it served as the reference. Two series of image datasets of structural abnormalities were randomly extracted for optimization and validation. The proportion of agreement on a per-lesion basis and receiver operating characteristics on a per-pixel basis between CAC and reference were analyzed for optimization. Thereafter, six readers independently categorized the regional ventilation in structural abnormalities in the validation set without and with a CAC map. Interobserver agreement was also compared between assessments without and with CAC maps using multirater κ statistics. Results Computer-aided classification maps were successfully generated in 31 patients (81.5%). The proportion of agreement and the average area under the curve of optimized CAC maps were 94% (75/80) and 0.994, respectively. Multirater κ value was improved from moderate (κ = 0.59; 95% confidence interval [CI], 0.56-0.62) at the initial assessment to excellent (κ = 0.82; 95% CI, 0.79-0.85) with the CAC map. Conclusion Our proposed CAC system demonstrated the potential for regional ventilation pattern analysis and enhanced interobserver agreement on visual classification of regional ventilation.