Radiation Dose Reduction in Digital Mammography by Deep-Learning Algorithm Image Reconstruction: A Preliminary Study

Purpose@#To develop a denoising convolutional neural network-based image processing technique and investigate its efficacy in diagnosing breast cancer using low-dose mammography imaging. @*Materials and Methods@#A total of 6 breast radiologists were included in this prospective study. All radiologists independently evaluated low-dose images for lesion detection and rated them for diagnostic quality using a qualitative scale. After application of the denoising network, the same radiologists evaluated lesion detectability and image quality. For clinical application, a consensus on lesion type and localization on preoperative mammographic examinations of breast cancer patients was reached after discussion. Thereafter, coded low-dose, reconstructed full-dose, and full-dose images were presented and assessed in a random order. @*Results@#Lesions on 40% reconstructed full-dose images were better perceived when compared with low-dose images of mastectomy specimens as a reference. In clinical application, as compared to 40% reconstructed images, higher values were given on full-dose images for resolution (p < 0.001); diagnostic quality for calcifications (p < 0.001); and for masses, asymmetry, or architectural distortion (p = 0.037). The 40% reconstructed images showed comparable values to 100% full-dose images for overall quality (p = 0.547), lesion visibility (p = 0.120), and contrast (p = 0.083), without significant differences. @*Conclusion@#Effective denoising and image reconstruction processing techniques can enable breast cancer diagnosis with substantial radiation dose reduction.

Artificial Intelligence for Breast Cancer Screening in Mammography (AI-STREAM): A Prospective Multicenter Study Design in Korea Using AI-Based CADe/x / 한국유방암학회지

Purpose@#Artificial intelligence (AI)-based computer-aided detection/diagnosis (CADe/x) has helped improve radiologists’ performance and provides results equivalent or superior to those of radiologists’ alone. This prospective multicenter cohort study aims to generate real-world evidence on the overall benefits and disadvantages of using AI-based CADe/x for breast cancer detection in a population-based breast cancer screening program comprising Korean women aged ≥ 40 years. The purpose of this report is to compare the diagnostic accuracy of radiologists with and without the use of AI-based CADe/x in mammography readings for breast cancer screening of Korean women with average breast cancer risk. @*Methods@#Approximately 32,714 participants will be enrolled between February 2021 and December 2022 at 5 study sites in Korea. A radiologist specializing in breast imaging will interpret the mammography readings with or without the use of AI-based CADe/x. If recall is required, further diagnostic workup will be conducted to confirm the cancer detected on screening. The findings will be recorded for all participants regardless of their screening status to identify study participants with breast cancer diagnosis within both 1 year and 2 years of screening. The national cancer registry database will be reviewed in 2026 and 2027, and the results of this study are expected to be published in 2027. In addition, the diagnostic accuracy of general radiologists and radiologists specializing in breast imaging from another hospital with or without the use of AI-based CADe/x will be compared considering mammography readings for breast cancer screening.DiscussionThe Artificial Intelligence for Breast Cancer Screening in Mammography (AI-STREAM) study is a prospective multicenter study that aims to compare the diagnostic accuracy of radiologists with and without the use of AI-based CADe/x in mammography readings for breast cancer screening of women with average breast cancer risk. AI-STREAM is currently in the patient enrollment phase.Trial RegistrationClinicalTrials.gov Identifier: NCT05024591

A Multicenter Prospective Validation Study for the Korean Thyroid Imaging Reporting and Data System in Patients with Thyroid Nodules

OBJECTIVE: To validate a new risk stratification system for thyroid nodules, the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), using a prospective design. MATERIALS AND METHODS: From June 2013 to May 2015, 902 thyroid nodules were enrolled from four institutions. The type and predictive value of ultrasonography (US) predictors were analyzed according to the combination of the solidity and echogenicity of nodules; in addition, we determined malignancy risk and diagnostic performance for each category of K-TIRADS, and compared the efficacy of fine-needle aspiration (FNA) with a three-tier risk categorization system published in 2011. RESULTS: The malignancy risk was significantly higher in solid hypoechoic nodules, as compared to partially cystic or isohyperechoic nodules (each p < 0.001). The presence of any suspicious US features had a significantly higher malignancy risk (73.4%) in solid hypoechoic nodules than in partially cystic or isohyperechoic nodules (4.3-38.5%; p < 0.001). The calculated malignancy risk in K-TIRADS categories 5, 4, 3, and 2 nodules were 73.4, 19.0, 3.5, and 0.0%, respectively; and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for malignancy were 95.5, 58.6, 44.5, 96.9, and 69.5%, respectively, in K-TIRADS categories 4 and 5. The efficacy of FNA for detecting malignancy based on K-TIRADS was increased from 18.6% (101/544) to 22.5% (101/449), as compared with the three-tier risk categorization system (p < 0.001). CONCLUSION: The proposed new risk stratification system based on solidity and echogenicity was useful for risk stratification of thyroid nodules and the decision for FNA. The malignancy risk of K-TIRADS was in agreement with the findings of a previous retrospective study.

Validity of breast-specific gamma imaging for Breast Imaging Reporting and Data System 4 lesions on mammography and/or ultrasound

PURPOSE: The purpose of this study was to assess the breast-specific gamma imaging (BSGI) in Breast Imaging Reporting and Data System (BI-RADS) 4 lesions on mammography and/or ultrasound. METHODS: We performed a retrospective review of 162 patients who underwent BSGI in BI-RADS 4 lesions on mammography and/or ultrasound. RESULTS: Of the 162 breast lesions, 66 were malignant tumors and 96 were benign tumors. Sensitivity and specificity of BSGI were 90.9% and 78.1%, and positive predictive value and negative predictive value were 74.1% and 92.6%. The sensitivity or specificity of mammography and ultrasound were 74.2% and 56.3% and 87.9% and 19.8%, respectively. The sensitivity and specificity of BSGI for breast lesions ≤1 cm were 88.0% and 86.8%, while the values of beast lesions >1 cm were 92.7% and 61.5%. The sensitivity or specificity of BSGI and mammography for patients with dense breasts were 92.0% and 81.3% and 72.0% and 50.0%, respectively. 26 patients showed neither a nodule nor microcalcification on ultrasound, but showed suspicious calcification on mammography. The sensitivity and specificity of BSGI with microcalcification only lesion were 75.0% and 94.4%. CONCLUSION: This study demonstrated that BSGI had shown high sensitivity and specificity, as well as positive and negative predictive values in BI-RADS 4 lesions on ultrasound and/or mammography. BSGI showed excellent results in dense breasts, in lesions that are less than 1 cm in size and lesions with suspicious microcalcification only.

Charcoal-Induced Granuloma That Mimicked a Nodal Metastasis on Ultrasonography and FDG-PET/CT after Neck Dissection

Charcoal can be used for preoperative localization of metastatic lymph nodes in the neck. Charcoal remains stable without causing foreign body reactions during as hort period. However, foreign body reactions may develop if charcoal is left in situ for more than 6 months. We reported a case of charcoal granuloma mimicking local recurrence on fluorodeoxyglucose-positron emission tomography/computed tomography and ultrasonography in a 47-year-old woman who had cervical lymph node dissection due to metastatic invasive ductal carcinoma of the breast.

The Korean guideline for breast cancer screening

Breast cancer is the second most common malignancy among Korean women. The 2002 National Cancer Center screening guideline breast cancer was revised via an evidence-based approach to provide medical personnel with a standard protocol of screening breast cancer. There is moderate-level evidence that biennial screening mammography in asymptomatic women aged 40 to 69 reduces breast cancer mortality, while low-level evidence suggests that screening mammography in women 70 years or older does not reduce breast cancer mortality. The committee concluded that the current evidence is insufficient to assess the benefits and harms of either ultrasonography or clinical breast examination as screening modalities for breast cancer. Future researches about the benefits and harms of the National Breast Cancer Screening Program in Korea are strongly required because the characteristics of breast cancer in Korea are different from those in the West, especially regarding dense breast. In conclusion, the committee recommends biennial screening mammography in asymptomatic women aged 40 to 69 years (grade B recommendation). The committee recommends selective screening mammography in women 70 years or older according to individual risk and preference (grade C recommendation). The committee neither recommends nor opposes ultrasonography and clinical breast examination as screening modalities (grade I recommendation). Symptomatic and high-risk women, however, should be offered complementary measures including ultrasonography and clinical breast examination under clinical supervision.

The Efficacy of Mammography Boot Camp to Improve the Performance of Radiologists

OBJECTIVE: To evaluate the efficacy of a mammography boot camp (MBC) to improve radiologists' performance in interpreting mammograms in the National Cancer Screening Program (NCSP) in Korea. MATERIALS AND METHODS: Between January and July of 2013, 141 radiologists were invited to a 3-day educational program composed of lectures and group practice readings using 250 digital mammography cases. The radiologists' performance in interpreting mammograms were evaluated using a pre- and post-camp test set of 25 cases validated prior to the camp by experienced breast radiologists. Factors affecting the radiologists' performance, including age, type of attending institution, and type of test set cases, were analyzed. RESULTS: The average scores of the pre- and post-camp tests were 56.0 +/- 12.2 and 78.3 +/- 9.2, respectively (p 0.05). CONCLUSION: The MBC improves radiologists' performance in interpreting mammograms irrespective of age and type of attending institution. Improved interpretation is observed for suspicious cases, but not for negative cases.

Image Reporting and Characterization System for Ultrasound Features of Thyroid Nodules: Multicentric Korean Retrospective Study

OBJECTIVE: The objective of this retrospective study was to develop and validate a simple diagnostic prediction model by using ultrasound (US) features of thyroid nodules obtained from multicenter retrospective data. MATERIALS AND METHODS: Patient data were collected from 20 different institutions and the data included 2000 thyroid nodules from 1796 patients. For developing a diagnostic prediction model to estimate the malignant risk of thyroid nodules using suspicious malignant US features, we developed a training model in a subset of 1402 nodules from 1260 patients. Several suspicious malignant US features were evaluated to create the prediction model using a scoring tool. The scores for such US features were estimated by calculating odds ratios, and the risk score of malignancy for each thyroid nodule was defined as the sum of these individual scores. Later, we verified the usefulness of developed scoring system by applying into the remaining 598 nodules from 536 patients. RESULTS: Among 2000 tumors, 1268 were benign and 732 were malignant. In our multiple regression analysis models, the following US features were statistically significant for malignant nodules when using the training data set: hypoechogenicity, marked hypoechogenicity, non-parallel orientation, microlobulated or spiculated margin, ill-defined margins, and microcalcifications. The malignancy rate was 7.3% in thyroid nodules that did not have suspicious-malignant features on US. Area under the receiver operating characteristic (ROC) curve was 0.867, which shows that the US risk score help predict thyroid malignancy well. In the test data set, the malignancy rates were 6.2% in thyroid nodules without malignant features on US. Area under the ROC curve of the test set was 0.872 when using the prediction model. CONCLUSION: The predictor model using suspicious malignant US features may be helpful in risk stratification of thyroid nodules.

Erratum: Image Reporting and Characterization System for Ultrasound Features of Thyroid Nodules: Multicentric Korean Retrospective Study

On page 110, the author (Won-Jin Moon)'s affiliation has been incorrectly marked as 6Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University, Seoul 143-729, Korea. The correct affiliation is 5Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul 143-729, Korea.

Thyroid Incidentaloma Detected by Time-Resolved Magnetic Resonance Angiography at 3T: Prevalence and Clinical Significance

OBJECTIVE: To determine the prevalence of thyroid incidentalomas detected by time-resolved magnetic resonance angiography (TRMRA) and to evaluate their clinical significance by using an ultrasonographic (US) and cytologic correlation. MATERIALS AND METHODS: We retrospectively reviewed 2010 consecutive TRMRA examinations performed at our institution between August 2006 and April 2010. The TRMRA findings of thyroid incidentalomas were analyzed according to location, size, as well as vascularity, and were correlated with the US findings and cytologic results. Each nodule was classified as suspiciously malignant, indeterminate or probably benign according to the US criteria recommended by the Korean Society of Thyroid Radiology. RESULTS: A total of 102 incidentalomas were detected in 90 of 2010 patients (5%). TRMRA showed homogenous hypervascularity in 48 (47%), inhomogeneous hypervascularity in 46 (45%), and hypovascularity in 8 (8%) thyroid nodules. At follow-up study, out of 26 patients with 30 incidentalomas on TRMRA, 27 nodules were identified on US. Of the 27 nodules, 24 (89%) nodule were classified as indeterminate, two (7%) as probably benign, and one (4%) as suspiciously malignant. Among the 16 nodules with available cytopathologic results, 14 (82%) were benign, one (6%) was indeterminate, and one (6%) was malignant. CONCLUSION: Thyroid incidentalomas are found in 5% of TRMRA examinations. Although their presence does not necessarily indicate malignancy, nonspecific findings of detected incidentalomas on TRMRA require further evaluation by US.

Invasive Ductal Carcinoma in a Mammary Hamartoma: Case Report and Review of the Literature

Mammary hamartomas are typically a benign condition and rarely develop into malignant lesions. Only 14 cases of carcinomas associated with a hamartoma have been documented in the literature. In this case report, we describe a case of invasive ductal carcinoma within a hamartoma in a 72-year-old woman. Mammography, ultrasonography, and magnetic resonance imaging showed the features of a typical hamartoma with a suspicious mass arising in it. This case illustrates the importance of identification of unusual findings in a typical mammary hamartoma on radiologic examinations.

Early Hepatocellular Carcinoma: Three-Phase Helical CT Features of 16 Patients

OBJECTIVE: To evaluate the three-phase helical CT features of early hepatocellular carcinomas, based on the new Japanese classification. MATERIALS AND METHODS: Over the course of an eight-year period, we collected 16 pathologically proven early hepatocellular carcinomas from 16 patients having undergone a three-phase helical CT prior to surgery. The three-phase CT images were acquired at 20-35 sec (arterial phase), 70 sec (portal phase), and 180 sec (equilibrium phase) from the begining of intravenous injection of contrast material. All the CT images were retrospectively analyzed by two radiologists in consensus, based on their description of morphologic (size, margin, fibrous capsule and mosaic pattern) and enhancement patterns of tumors. RESULTS: Only seven (44%) of the 16 early hepatocellular carcinomas having undergone a CT were described (mean diameter, 1.2 cm; range, 0.4-2.5 cm). All the tumors had an ill-defined margin with no fibrous capsule. The mosaic pattern was found in only one tumor. Only three (43%) of the seven tumors detected on CT were hyperattenuating during the arterial phase. The four remaining tumors (25%) were hypoattenuating throughout the three phases. CONCLUSION: Despite the higher resolution provided by the three phase scans, the contrast-enhanced CT provides only limited detection of the variable morphologic and enhancement features of early hepatocellular carcinomas.

Targeted Ultrasound for MR-Detected Lesions in Breast Cancer Patients

OBJECTIVE: To investigate the usefulness of targeted ultrasound (US) in the identification of additional suspicious lesions found by magnetic resonance (MR) imaging in breast cancer patients and the changes in treatment based on the identification of the lesions by the use of targeted US. MATERIALS AND METHODS: One-hundred forty nine patients who underwent breast MR imaging for a preoperative evaluation of breast cancer between January 2002 and July 2004 were included in the study. We searched all cases for any additional lesions that were found initially by MR imaging and investigated the performance of targeted US in identifying the lesions. We also investigated their pathological outcomes and changes in treatment as a result of lesion identification. RESULTS: Of the 149 patients with breast cancer, additional suspicious lesions were detected with MR imaging in 62 patients (42%). Of the 69 additional lesions found in those 62 patients, 26 (38%) were confirmed as cancers by histology. Thirty-eight lesions in 31 patients were examined with targeted US and were histologically revealed as cancers in 18 (47%), high risk lesions in two (5%), benign lesions in 15 (39%), and unidentified lesions in three (8%). The cancer rate was statistically higher in lesions with a US correlate than in lesions without a US correlate (p = 0.028). Of 31 patients, the surgical plan was altered in 27 (87%). The use of targeted US justified a change in treatment for 22 patients (81%) and misled five patients (19%) into having an unnecessary surgical excision. CONCLUSION: Targeted US can play a useful role in the evaluation of additional suspicious lesions detected by MR imaging in breast cancer patients, but is limited in lesions without a US correlate.

A Metastatic Paraganglioma presenting as Multiple Intrapulmonary Nodules

A 24-year-old man that had previously undergone a complete resection of a cervical paraganglioma presented with multiple well-defined intrapulmonary nodules on contrast-enhanced computed tomography. All of the nodules showed homogeneously intense enhancement. The largest nodule was a hot spot on F-18 fluorodeoxyglucose positron emission tomography. It was diagnosed as a paraganglioma using wedge resection via video-assisted thoracoscopic resection. Paragangliomas are rare neuroendocrine tumors and are exceedingly rare in the lung parenchyma. A few reports have described one or two intrapulmonary lesions, including primary tumors and metastases. We report a unique case of a multiple metastatic paraganglioma in the parenchyma of both lungs.

US Diagnosis of Mature Cystic Teratomas of the Ovary: Morphologic Analysis of 112 Pathologically Proven Cases

n in 93 of the 112 tumors (83.0%), with pure cystic masses (types I-III) accounted for the remaining 19 tumors (17.1 %). Of the 112 tumors, 68 (67.1%) showed posterior sonic shadowing which was demonstrated only in the hyperechoic area of types IV-VI. CONCLUSION: Any adnexal masses representing a hyperechoic area within a cyst, solid and cystic tumors containing hyperechogenicity or diffusely hyperechoic mass, especially when accompanied by posterior sonic shadowing, should be suspected as indicative of mature cystic teratoma.

Comparative study of STIR image with SE image in diagnosis of the orbital disease

To evaluate the efficacy of STIR (short tau inversio recovery) image in the diagnosis of orbital diseases, we compared the STIR images with conventional SE(spin-echo) images in 17 patients. The fat signal was reliably nulled at inversion time of approximately 160-170 msec in all cases. We analyzed all the cases in the aspects of the detection of lesion and the lesion-to-back ground contrast retrospectively. Regarding lesion, the detection rates of STIR, T1 and T2-weighted images were 89, 88 and 83% respectively. In the aspect of lesion-to-background contrast, the contrast ratios of STIR and T1, T2-weighted image were 87% and 64, 56%, respectively. In conclusion, STIR images were similar to T1-and T2-weighted images in the detection of lesion, but superior in the aspect of lesion-to-background contrast. So the STIR images may be a useful adjunct to conventional SE images for the diagnosis of orbital disease.