Hyun Sil Lee

Perfusion Parameters in Dynamic Contrast-enhanced MRI and Apparent Diffusion Coefficient Value in Diffusion-weighted MRI:: Association with Prognostic Factors in Breast Cancer

RATIONALE AND OBJECTIVES To evaluate the association of prognostic factors and subtypes of breast cancer with perfusion parameters in dynamic contrast-enhanced magnetic resonance imaging and apparent diffusion coefficient (ADC) values in diffusion-weighted magnetic resonance imaging. MATERIALS AND METHODS Quantitative perfusion parameters (constant of transfer from plasma to interstitium, constant of transfer from the interstitium to the plasma, extravascular/extracellular volume per unit of volume of tissue [ve], and initial area under the concentration curve [iAUC]) and ADC values in the entire tumor volume of 52 invasive ductal carcinomas were obtained using histogram analysis. Four measures (25th percentile, mean, median, 75th percentile) were calculated for each parameter and the ADC value. Associations of perfusion parameters and ADC values with prognostic factors and tumor subtypes were analyzed. RESULTS Among perfusion parameters, iAUCmean and iAUCmedian were greater in tumors larger than 2 cm (8.23 ± 2.33, 8.64 ± 2.67 × 10(4)) than in those smaller than 2 cm (6.99 ± 1.92, 7.04 ± 2.15 × 10(4); P = 0.046, 0.023). Ve median was higher in tumors with progesterone receptor (PR) positivity (0.54 ± 0.18) than in those with PR negativity (0.44 ± 0.1, P = 0.041). There were higher ADCmean and ADCmedian in tumors with human epidermal growth factor receptor 2 (HER2) positivity (1.306 and 1.278 × 10(-3)mm(2)/s) than in those with HER2 negativity (1.078 and 1.053 × 10(-3)mm(2)/s; P = 0.012 and 0.020). Higher ADCmean and ADCmedian were observed in HER2-enriched type (1.404 and 1.378 × 10(-3)mm(2)/s) than in luminal type (1.096 and 1.073 × 10(-3)mm(2)/s; P = 0.030 and 0.045). CONCLUSIONS Among perfusion parameters, iAUC was associated with tumor size and ve median was associated with PR positivity. Mean and median ADC values showed positive correlation with HER2-positive and HER2-enriched tumors.

Clinical Features and Prognosis of Invasive Pulmonary Aspergillosis in Korean Children with Hematologic/Oncologic Diseases

Invasive pulmonary aspergillosis (IPA) is the most frequent form of invasive fungal diseases in immunocompromised patients. However, there are only a few studies on IPA in immunocompromised children in Korea. This study was designed to characterize IPA in Korean children with hematologic/oncologic diseases. Medical records of children with hematologic/oncologic diseases receiving antifungal therapy were reviewed. The enrolled children were divided into the IPA group (proven and probable IPA) and non-IPA group, and the clinical characteristics and prognosis were compared between the two groups. During the study period, 265 courses of antifungal therapy were administered to 166 children. Among them, two (0.8%) episodes of proven IPA, 35 (13.2%) of probable IPA, and 52 (19.6%) of possible IPA were diagnosed. More children in the IPA group suffered from neutropenia lasting for more than two weeks (51.4% vs. 21.9%, P<0.001) and showed halo signs on the chest computed tomography (78.4% vs. 40.7%, P<0.001) than in the non-IPA group. No other clinical factors showed significant differences between the two groups. Amphotericin B deoxycholate was administered as a first line antifungal agent in 33 (89.2%) IPA group episodes, and eventually voriconazole was administered in 27 (73.0%) episodes. Ten (27.0%) children in the IPA group died within 12 weeks of antifungal therapy. In conclusion, early use of chest computed tomography to identify halo signs in immunocompromised children who are expected to have prolonged neutropenia can be helpful for early diagnosis of IPA and improving prognosis of children with IPA. Graphical Abstract

Diagnostic Performance of and Breast Tissue Changes at Early Breast MR Imaging Surveillance in Women after Breast Conservation Therapy

Purpose To investigate the diagnostic performance and tissue changes in early (1 year or less) breast magnetic resonance (MR) imaging surveillance in women who underwent breast conservation therapy for breast cancer. Materials and Methods This prospective study was approved by the institutional review board, and written informed consent was obtained. Between April 2014 and June 2016, 414 women (mean age, 51.5 years; range, 21-81 years) who underwent 422 early surveillance breast MR imaging examinations (median, 6.0 months; range, 2-12 months) after breast conservation therapy were studied. The cancer detection rate, positive predictive value of biopsy, sensitivity, specificity, accuracy, and area under the curve of surveillance MR imaging, mammography, and ultrasonography (US) were assessed. Follow-up was also obtained in 95 women by using positron emission tomography (PET)/computed tomography (CT). Background parenchymal enhancement (BPE) changes in the contralateral breast were assessed according to adjuvant therapy by using the McNemar test. Results Of 11 detected cancers, six were seen at MR imaging only, one was seen at MR imaging and mammography, two were seen at MR imaging and US, one was seen at mammography only, and one was seen at PET/CT only. Three MR imaging-depicted cancers were observed at the original tumor bed, and two MR imaging-depicted cancers were observed adjacent to the original tumor. Among two false-negative MR imaging diagnoses (two cases of ductal carcinoma in situ), one cancer had manifested as calcifications at mammography without differentiated enhancement at MR imaging, and the other cancer was detected at PET/CT, but MR imaging results were negative because of marked BPE, which resulted in focal lesion masking. The positive predictive value of biopsy and the sensitivity, specificity, accuracy, and area under the curve for MR imaging were 32.1% (nine of 28), 81.8% (nine of 11), 95.1% (391 of 411), 94.7% (400 of 422), and 0.88, respectively. The sensitivity of surveillance MR imaging (81.8%; 95% confidence interval [CI]: 48.2%, 97.7%) was higher than that of mammography (18.2%; 95% CI: 2.3%, 51.8%) and US (18.2%; 95% CI: 2.3%, 51.8%), with an overlap in CIs. The BPE showed a significant decrease in the group of patients who received adjuvant chemotherapy (43 BPE decreases and four BPE increases) and the group of patients who received hormone therapy (55 BPE decreases and two BPE increases) (P < .0001 for both). Conclusion Early MR imaging surveillance after breast conservation therapy can be useful in patients who have breast cancer, with superior sensitivity compared with that of mammography and US. The BPE tends to be decreased at short-term follow-up MR imaging in patients who receive adjuvant therapy.

USPIO enhanced lymph node MRI using 3D multi-echo GRE in a rabbit model

Ultrasmallsuperparamagnetic iron oxide (USPIO) has been suggested to be a negative MR contrast agent to detect metastatic lymph nodes. Previously reported studies have evaluated the diagnostic performance of USPIO-enhanced MR lymph node imaging based on signal intensity. In this study, we investigate the specific performance of three different parametric approaches (normalized signal intensity, R2 * and susceptibility) using 3D multi-echo gradient echo to quantify the USPIO particles in lymph nodes. Nine rabbits with VX2 tumor implants were scanned before and after USPIO injection. From 3D multi-echo GRE magnitude and phase data, we generated multi-echo combined T2 *-weighted images, an R2 * map, and a quantitative susceptibility map. Eighteen lymph nodes (nine reactive and nine metastatic) were evaluated and showed remarkable signal drops in the area of USPIO accumulation. On parametric analysis, the R2 * difference before and after USPIO injection was significantly different (p < 0.05) between reactive and metastatic lymph nodes; in contrast, the normalized signal intensity and susceptibility were not significantly different between the nodes. Our study showed the potential utility of USPIO-enhanced MRI using R2* mapping from 3D multi-echo GRE for the detection of lymph node metastasis and parametric analysis of lymph node status in a rabbit model. Copyright

Application of computer-aided diagnosis in breast ultrasound interpretation: Improvement in diagnostic performances according to reader experience

Purpose The purpose of this study was to evaluate the usefulness of applying computer-aided diagnosis (CAD) to breast ultrasound (US), depending on the readers experience with breast imaging. Methods Between October 2015 and January 2016, two experienced readers obtained and analyzed the grayscale US images of 200 cases according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon and categories. They additionally applied CAD (S-Detect) to analyze the lesions and made a diagnostic decision subjectively, based on grayscale US with CAD. For the same cases, two inexperienced readers analyzed the grayscale US images using the BI-RADS lexicon and categories, added CAD, and came to a subjective diagnostic conclusion. We then compared the diagnostic performance depending on the readers experience with breast imaging. Results The sensitivity values for the experienced readers, inexperienced readers, and CAD (for experienced and inexperienced readers) were 91.7%, 75.0%, 75.0%, and 66.7%, respectively. The specificity values for the experienced readers, inexperienced readers, and CAD (for experienced and inexperienced readers) were 76.6%, 71.8%, 78.2%, and 76.1%, respectively. When diagnoses were made subjectively in combination with CAD, the specificity significantly improved (76.6% to 80.3%) without a change in the sensitivity (91.7%) in the experienced readers. After subjective combination with CAD, both of the sensitivity and specificity improved in the inexperienced readers (75.0% to 83.3% and 71.8% to 77.1%). In addition, the area under the curve improved for both the experienced and inexperienced readers (0.84 to 0.86 and 0.73 to 0.80) after the addition of CAD. Conclusion CAD is more useful for less experienced readers. Combining CAD with breast US led to improved specificity for both experienced and inexperienced readers.

Clinical utility of the radiation dose management system for full field digital mammography (FFDM): In Asian women with dense breast tissue.

70 Background: In the perspectives on radiation dose, there are consensus of importance on radiation dose management for patient safety and trends to reduce radiation dose for patient safety. Radiation dose management system like Radimetrics helps radiologists optimize protocols and reduce radiation dose. There is no previous data applying the radiation dose management system in mammography.We investigated the clinical usefulness of the radiation dose management system in full field digital mammography (FFDM) using commercial Radiation dose management system. METHODS We did radiation dose tracking, monitoring, and statistics through the existed radiation dose management system (Radimetrics). The utilization data, parameter, and dose report were sent to the conventional picture archiving and communication system (PACS) and the Radimetrics enterprise flat form. And we could review the data including age, kVp, mAs, breast thickness, and compression force under the web base. We analyzed the breast composition depending on the BI-RADS assessment categories. We evaluated the correlation of the age, kVp, mAs, breast thickness, compression force, and breast composition with organ dose of breast. Additionally, in patients with above diagnostic reference level ( ≥ 75%) of radiation dose, the causes were analyzed. RESULTS From February to May 2015, 3076 sets of FFDM were performed and sent to PACS and the radiation dose management system (Radimetrics). In total 3076 sets, 2520 were routine bilateral FFDM with 4 views. The mean glandular dose was 6.59± 2.87 mGy (2.63-18.46). In the correlation analysis, the age had moderate negative linear relationship with organ dose. The mAs and breast composition had moderate positive linear relationship with organ dose. The kVp, breast thickness, and compression force had weak positive linear relationship with organ dose. Patients with above diagnostic reference level ( ≥ 75%) of radiation dose showed dense breast composition and thicker breast. CONCLUSIONS The radiation dose management system is useful in FFDM. Especially in Asian women with thick and dense breasts, radiation dose should be carefully managed.

Imaging features of bilateral breast plasmacytoma as unusual initial presentation of multiple myeloma: case report and literature review.

Breast plasmacytoma (BP) is an extremely rare extramedullary manifestation of multiple myeloma (MM). We report the imaging findings of an unusual case in which BP was the initial presentation of MM. A 53-year-old woman with no contributory medical history underwent chest computed tomography to evaluate intermittent nocturnal anterior chest pain, and bilateral multiple breast masses were found. Following an ultrasound-guided core needle biopsy, these lesions were confirmed to be BP.