Yun-Jin Jang

Accuracy of preoperative MRI in predicting pathology stage in rectal cancers: node-for-node matched histopathology validation of MRI features.

BACKGROUND: Few studies that meticulously match individual lymph nodes seen on MRI with their precise histologic counterparts after total mesorectal excision have been reported. OBJECTIVE: The objective of this study was to determine whether preoperative MRI could detect lymph node metastases accurately in the node-by-node analysis. DESIGN: This was a prospective, observational cohort study. SETTINGS: The study was conducted at a tertiary-care hospital. PATIENTS: Forty patients with rectal cancer were enrolled. MAIN OUTCOME MEASURES: Specimens were assessed using MRI for clinical staging. After surgical resection of the tumor, the specimens were again imaged with ex vivo ultrasound scan to localize the perirectal node. The locations of each lymph node were precisely matched with its corresponding magnetic resonance image to enable a node-for-node comparison of magnetic resonance images and histologic findings. RESULTS: Agreement between MRI and histologic assessment of T stage was 82.5%. Of the 341 nodes harvested, 120 were too small (<3 mm) to be depicted on magnetic resonance images, and 18 of these contained metastasis (15%). A correlation between the results of MRI and histopathology was feasible for 205 lymph nodes, and the overall success rate of matching between the 2 techniques was 91.1% (205 of 221). Preoperative MRI revealed a node-by-node sensitivity and positive predictive value of 58.0%, and 61.7%. There was no difference in the diagnostic accuracy between the primary surgery subgroup and preoperative radiation subgroups. LIMITATIONS: The study is limited by its heterogeneity of cohorts including the subgroup with preoperative chemoradiation and the lack of preoperative ultrasound assessment. CONCLUSIONS: Preoperative MRI was moderately accurate for the prediction of mesorectal lymph node metastasis. Moreover, preoperative MRI was insufficient for detecting small lymph nodes (<3 mm) with metastasis.

Locally advanced rectal cancer: post-chemoradiotherapy ADC histogram analysis for predicting a complete response

Background The value of diffusion-weighted imaging (DWI) for reliable differentiation between pathologic complete response (pCR) and residual tumor is still unclear. Recently, a few studies reported that histogram analysis can be helpful to monitor the therapeutic response in various cancer research. Purpose To investigate whether post-chemoradiotherapy (CRT) apparent diffusion coefficient (ADC) histogram analysis can be helpful to predict a pCR in locally advanced rectal cancer (LARC). Material and Methods Fifty patients who underwent preoperative CRT followed by surgery were enrolled in this retrospective study, non-pCR (n = 41) and pCR (n = 9), respectively. ADC histogram analysis encompassing the whole tumor was performed on two post-CRT ADC600 and ADC1000 (b factors 0, 600 vs. 0, 1000 s/mm2) maps. Mean, minimum, maximum, SD, mode, 10th, 25th, 50th, 75th, 90th percentile ADCs, skewness, and kurtosis were derived. Diagnostic performance for predicting pCR was evaluated and compared. Results On both maps, 10th and 25th ADCs showed better diagnostic performance than that using mean ADC. Tenth percentile ADCs revealed the best diagnostic performance on both ADC600 (AZ 0.841, sensitivity 100%, specificity 70.7%) and ADC1000 (AZ 0.821, sensitivity 77.8%, specificity 87.8%) maps. In comparison between 10th percentile and mean ADC, the specificity was significantly improved on both ADC600 (70.7% vs. 53.7%; P = 0.031) and ADC1000 (87.8% vs. 73.2%; P = 0.039) maps. Conclusion Post-CRT ADC histogram analysis is helpful for predicting pCR in LARC, especially, in improving the specificity, compared with mean ADC.

Efficacy of US-guided Percutaneous Cholecystocholangiography for the Early Exclusion and Type Determination of Biliary Atresia

PURPOSE To evaluate the efficacy of ultrasonographically (US)-guided percutaneous cholecystocholangiography (PCC) for early diagnosis and characterization of biliary atresia in infants with cholestatic liver disease. MATERIALS AND METHODS Institutional review board approval was obtained for this study. Parental informed written consent was obtained. From October 2003 to August 2010, 22 infants (12 male, 10 female; age range, 1-138 days) were referred to the radiology department for PCC. Indications for PCC were suspected biliary atresia at 24-hour delayed technetium 99m-diisopropyl-phenylcarbamoylmethyl-iminodiacetic acid (DISIDA) scintigraphy because no excretion was observed in the small bowel (n = 17) or when the results of the scan or liver biopsy could not be obtained within 3 days because of a delay in schedule (n = 5). A diagnosis of biliary atresia was excluded when there was contrast material visualized in the gallbladder, biliary system, and passage to the duodenum. Patients with biliary atresia underwent surgery as the reference standard. RESULTS Among the 18 patients who underwent successful PCC, biliary atresia was excluded in 13, with diagnoses as follows: total parenteral nutrition-associated cholestasis (TPNAC) (n = 6), neonatal hepatitis (n = 4), congenital syphilis (n = 1), neonatal lupus (n = 1), and congenital cytomegalovirus hepatitis (n = 1). Biliary atresia was diagnosed in five patients (four with type IIIb and one with type IIIa) and was confirmed at surgery. In four infants in whom US-guided gallbladder puncture had failed, biliary atresia (n = 2) and TPNAC (n = 2) were diagnosed. CONCLUSION PCC is a safe and useful technique for early exclusion when biliary atresia cannot be ruled out after traditional screening tests; in addition, it may be useful for preoperative type determination of biliary atresia.

Ultrasonographic detection and characterization of asymptomatic ductal carcinoma in situ with histopathologic correlation

Background Most ductal carcinoma in situ (DCIS) of the breast is asymptomatic and usually manifests as calcifications in screening mammography. On the other hand, little is known about ultrasonographic (US) features of asymptomatic DCIS, for US is rarely used for the diagnosis and evaluation of DCIS because of low sensitivity in detecting microcalcifications. Purpose To evaluate US detection and characterization of DCIS in asymptomatic women and correlate these imaging findings with the histopathologic features. Material and Methods This retrospective study evaluated mammographic and US images of 60 DCIS cases from 59 asymptomatic women. US was performed in knowledge of mammographic findings. The following histopathologic parameters were analyzed: Van Nuys classification, architectural pattern, and presence of microinvasion. Image detectability and US features were correlated with these histopathologic parameters. Results Of the 54 cases (90.0%) detected on mammography, 48 cases (88.9%) had microcalcifications only, 5 (9.3%) had microcalcifications with associated density, and 1 (1.9%) had soft tissue density alone. Of the 38 cases (63.3%) identified by US, 29 cases (76.3%) had a mass with or without microcalcifications, six (15.8%) had microcalcifications only, and three (7.9%) had other findings. US identified lesions were associated with higher Van Nuys groups, microinvasion and comedocarcinoma (P = 0.044, P = 0.024, and P = 0.032, respectively). The most common US finding was a not-circumscribed, oval mass with parallel orientation and normal acoustic transmission. Microcalcifications were seen on US in 31 (81.6%) of the 38 US visible cases; this finding showed a trend of association with Van Nuys group 2 and 3 but was not statistically significant (P = 0.063). Conclusion When DCIS was identified on US, it was associated with more aggressive histopathologic type. However, mammographic correlation is essential to differentiate benign from malignant lesion in cases seen by US; US findings of asymptomatic DCIS had a low suspicion of malignancy.

Prognostic Stratification by Extramural Depth of Tumor Invasion of Primary Rectal Cancer Based on the Radiological Society of North America Proposal

OBJECTIVE The purpose of this study was to investigate the diagnostic performance of MRI in stratifying tumors stage III (T3) in patients with rectal cancer by measuring the extramural depth of tumor invasion based on the Radiologic Society of North America (RSNA) proposal and to validate its role as a prognostic indicator. MATERIALS AND METHODS From January 2006 to July 2009, 146 patients with surgically and pathologically confirmed T3 rectal adenocarcinoma who underwent preoperative MRI were enrolled. Two blinded radiologists measured the maximum extramural depth of tumor invasion on T2-weighted images. To evaluate the diagnostic performance of MRI for stratifying subgroups, the study population was assigned into three subgroups (T3a, T3b, and T3c) according to extramural depth of tumor invasion (< 5, 5-10, and > 10 mm).To validate the role of extramural depth of tumor invasion as a prognostic indicator, Cox regression analysis was used for estimation of independent risk factors for postoperative recurrence. Three-year recurrence-free survival was evaluated by the Kaplan-Meier method with a log-rank test. Histopathologic reports were used as the reference standard. RESULTS The overall accuracy of MRI for stratifying subgroups was 71.2% (104/146) and 77.4% (113/146) for reviewers 1 and 2. Extramural depth of tumor invasion was an independent risk factor for 3-year recurrence-free survival (hazard ratio, 2.186; 95% CI, 1.336-3.577; p = 0.002). Kaplan-Meier curves revealed a significant difference in 3-year recurrence-free survival rates for each subgroup (86%, 69%, and 43% for T3a, T3b, and T3c; p < 0.03). CONCLUSION MRI can be used for prognostic stratification according to extramural depth of tumor invasion based on the RSNA proposal for patients with T3 rectal cancer.

Incidental Breast Lesions Identified by 18F-FDG PET/CT: Which Clinical Variables Differentiate between Benign and Malignant Breast Lesions?

Purpose The aim of our study was to evaluate the risk of malignancy and to determine which clinical variables differentiate between benign and malignant focal breast lesions found incidentally on 18F-flourodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT). Methods From March 2005 to October 2011, 21,224 women with no history of breast cancer underwent FDG PET/CT at three university-affiliated hospitals. We retrospectively identified 214 patients with incidental focal hypermetabolic breast lesions and grouped them into benign and malignant lesion groups. Of the 214 patients, 82 patients with 91 lesions were included in this study. All lesions were confirmed histologically or were assessed by follow-up imaging for greater than 2 years. The patient age, maximum standardized uptake value (SUVmax), lesion size on ultrasonography (US), and Breast Imaging-Reporting and Data System (BI-RADS) category on US in conjunction with mammography were compared between the groups. Multivariate logistic regression analysis was used to identify independent factors associated with malignancy. Results The risk of malignancy was 29.7% (27/91) in breast incidentalomas detected by FDG PET/CT. The univariate analysis showed that the patient age, SUVmax, tumor size, and BI-RADS category differed significantly between the malignant and benign groups. The multivariate analysis showed that the BI-RADS category was the only significant factor differentiating benign from malignant lesions (p=0.002). Conclusion BIRADS category based on US in conjunction with mammography was the only useful tool to differentiate between malignant and benign lesions in breast incidentalomas on FDG PET/CT.

Variation in hepatic segmental volume distribution according to different causes of liver cirrhosis: CT volumetric evaluation.

Objective To investigate if there is difference in hepatic segmental volume distribution according to causes of liver cirrhosis (LC) using computed tomography volumetric analysis. Methods On computed tomographic scans, hepatic segmental volumes were measured in 90 patients with LC of 4 different causes (alcohol, hepatitis B virus (HBV), hepatitis C virus (HCV), and cryptogenic cirrhosis). The volumetric indices were compared. Results The volume proportion of the lateral segment in the liver in patients with HBV was significantly higher than in the patients with HCV (P = 0.038). Hepatic volume distribution in alcoholic LC showed differences: larger caudate lobe volume than HBV- and HCV-induced LC (P = 0.029 and P = 0.031), larger right lobe volume (P = 0.043) and smaller proportion of the lateral segment in the liver (P = 0.003) than in HBV-induced LC. Conclusions Computed tomography volumetric analysis showed differences in hepatic segmental volume distribution in cirrhotic patients according to causes of LC.

Eosinophilic gastritis with gastric outlet obstruction mimicking infantile hypertrophic pyloric stenosis.

PATIENT 1 A 1-month-old baby presented with persistent vomiting since birth. Because of his mother’s misbelief that breast-feeding is associated with vomiting, breast-feeding was changed to cow’s milk formula in just a few days after birth. Nevertheless, vomiting became worse and body weight did not increase satisfactorily (25th–50th percentile at birth; 10th–25th percentile 1 month later), which led the patient to be admitted to the hospital. Physical examination was unremarkable at admission. To exclude infantile hypertrophic pyloric stenosis (IHPS), ultrasonography (USG) was performed, demonstrating segmental concentric layered wall thickening in the gastric antrum and intact pylorus and duodenal bulb (Fig. 1A). Following the upper gastrointestinal (GI) series (UGI) showed severe gastric outlet obstruction and little passage of contrast to duodenum on 6 hours’ delayed image (Fig. 1B). Peripheral eosinophil count and serum IgE level were not elevated. Esophagogastroduodenoscopy (EGD) revealed prominent antral swelling with pyloric narrowing. Biopsy was performed and feeding tube (5 Fr, 500 mm, JMS-K, Hankuk Medical Supply, Republic of Korea) was inserted postpylorus. Histopathologic examination showed eosinophilic infiltration (>20 eosinophils/HPF) in the antrum and pylorus (Fig. 1C). Final diagnosis was eosinophilic gastritis. This patient was fed with amino acid–based formula by transpyloric feeding tube, treated with corticosteroid (Solumedrol [methyl prednisolone sodium succinate], through IV side), administered for a duration of 4 to 8 days, depending on the patient’s symptom for five times and then followed by USG, UGI, and EGD. Oral ketotifen was added. Gastric wall thickening had hardly improved on follow-up USG, but barium passage had improved gradually. Transpyloric feeding tube was removed after 3 months. EGD performed 3 days later showed resolved antral swelling. On the last follow-up, the patient was about 1-year old with body weight in the 75th to 90th percentile, and GI symptoms did not relapse.

Serial Ultrasound Findings After Laser Ablation for Benign Breast Lesions on Long-Term Follow-Up: Implications for Evaluation of Procedural Success

OBJECTIVE The purpose if this study was to describe the follow-up ultrasound (US) findings of percutaneous US-guided laser ablation for small benign breast lesions, and to define the procedural success. BACKGROUND DATA There are limited reports on follow-up imaging after laser ablation, because the ablated tumors were generally resected by surgery. MATERIALS AND METHODS US-guided laser ablation was performed on 19 benign breast lesions in 10 patients. The median size of the lesions was 7.8 mm (range, 3-11 mm). The lesions were diagnosed as image-pathology concordant benign by US-guided core biopsy. After ablation, we performed follow-up US with an interval of 3-12 months; the median follow-up period was 32 months (range, 30-36 months). We evaluated the morphologic and size changes by using serial follow-up US. RESULTS US findings of the 13 cases followed within the first 6 months after ablation showed hypoechoic lesions having inner hyperechogenicity with or without a hypoechoic center. The size of these lesions during this period increased in comparison with the initial lesion size, and then decreased or became stable on serial follow-up US. On the last follow-up US examination, in 14 cases (73.6%), the lesions were invisible, 4 cases (21.1%) showed scar changes, and 1 case (5.3%) showed a hypoechoic remnant lesion. CONCLUSIONS US findings within 6 months after laser ablation showed mixed echoic lesions with increased size, followed by gradual decrease in size. Therefore, the success of laser ablation may be evaluated by checking the changes in the lesions by comparing the size of the lesions with the first follow-up US within 6 months and not the original tumor.