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.

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

This corrects the article on p. 57 in vol. 25, PMID: 35133093.

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

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. DISCUSSION: The 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 REGISTRATION: ClinicalTrials.gov Identifier: NCT05024591.

Diagnostic Performance of Ultrasound-Based Risk-Stratification Systems for Thyroid Nodules: Comparison of the 2015 American Thyroid Association Guidelines with the 2016 Korean Thyroid Association/Korean Society of Thyroid Radiology and 2017 American College of Radiology Guidelines.

PURPOSE: The aim of this study was to compare the diagnostic performance of ultrasound (US)-based risk-stratification systems for thyroid nodules in the 2015 American Thyroid Association (ATA) guidelines with those of the 2016 Korean Thyroid Association (KTA)/Korean Society of Thyroid Radiology (KSThR) and 2017 American College of Radiology (ACR) guidelines. METHODS: From June 2013 to May 2015, a total of 902 consecutive thyroid nodules were enrolled in four institutions, and their US features were retrospectively reviewed and classified using the categories defined by the three guidelines. The malignancy risk of each category, as defined by all three risk-stratification systems, was calculated, and the diagnostic performance of the fine-needle aspiration (FNA) indications of the ATA guidelines were compared to those of the KTA/KSThR and ACR guidelines. RESULTS: Of all nodules, 636 (70.5%) were benign and 266 (29.5%) malignant. The calculated malignancy risks for ATA categories 5, 4, 3, 2, and 1 nodule(s) were 71.7, 21.5, 2.6, 3.8, and 0%. Of all nodules, 7.6% (69/902) did not meet the ATA pattern criteria, but the malignancy risk was calculated to be 10.1% (7/69). The ATA guidelines afforded significantly higher diagnostic sensitivity (95.0%) than the ACR guidelines (80.2%; p = 0.001) but a lower specificity (38.1 vs. 68.9%; p < 0.001). On the other hand, the ATA guidelines exhibited a lower diagnostic sensitivity than the KTA/KSThR guidelines (100.0%; p = 0.07) but a higher specificity (28.2%; p < 0.001). The unnecessary FNA rate was the lowest when the ACR guidelines were used (25.8%), followed by the ATA (51.2%) and KTA/KSThR (59.4%) guidelines. CONCLUSION: The 2015 ATA guidelines afford relatively moderate sensitivity and an unnecessary FNA rate for thyroid cancer detection compared to the 2016 KTA/KSThR and 2017 ACR guidelines. US practitioners require a deep understanding of the benefits and risks of the US-based FNA criteria of different guidelines and potential impact on the diagnosis of low-risk thyroid cancers.

Mammographic and ultrasound findings in poroid hidradenoma of the breast mimicking intraductal papilloma and papillary carcinoma: A case report.

RATIONALE: Poroid hidradenoma (PH) is a rare variant of benign sweat gland neoplasm without connection to the epidermis. This tumor presents clinically as a solitary lesion with a cystic component located in the subcutaneous layer abutting the skin. On ultrasound, it appears as a circumscribed complex cystic and solid mass abutting the dermis. The occurrence of PH in the breast is very rare. Its features overlap with intraductal papilloma and papillary carcinoma. PATIENT CONCERNS: A 66-year-old woman presented with a palpable lump in her right breast. DIAGNOSES: Clinical examination revealed dark bluish dome-shaped nodule which presented as circumscribed round isodense mass on mammography and oval complex cystic and solid mass abutting the dermis on ultrasound. Clinically, a papillary neoplasm was suspected. INTERVENTIONS: The patient underwent En bloc surgical excision including the overlying epidermis and the surrounding adipose tissue to prevent recurrence. OUTCOMES: A well-demarcated, non-encapsulated grayish white mass composed of a partly solid and partly cystic area was completely removed and histopathologically confirmed as PH. At the 12-month follow-up, no recurrence was evident. LESSONS: PH should be considered in the differential diagnosis of a slowly growing breast mass that is bluish, cystic, and solid and abuts the dermis.

Usefulness of abbreviated breast MRI screening for women with a history of breast cancer surgery.

PURPOSE: We investigated the usefulness of abbreviated breast MRI (AB-MRI), including fat-suppressed T2-weighted imaging, pre- and postcontrast image acquisition, and subtracted maximum-intensity projection imaging, for the screening of women with a history of breast cancer surgery. METHODS: Between October 2014 and March 2016, a total of 799 AB-MRI examinations were performed for 725 women with a history of breast cancer surgery. The image acquisition time was 8.5 min. Screening mammography, ultrasound, and AB-MRI were generally performed around the same time. The cancer detection rate, positive predictive values for recall and biopsy, sensitivity and specificity of screening MRI, and rate of malignancy belonging to each breast imaging reporting and data system (BI-RADS) category were assessed. RESULTS: AB-MRI detected 12 malignancies in 12 women (15.0 cancers per 1000 cases). Seven of these 12 malignancies were initially invisible on ultrasound and mammography, although subsequent targeted ultrasound revealed lesions corresponding to the MRI-detected lesions. The positive predictive values for recall and biopsy and sensitivity and specificity values for screening MRI were 12.4, 61.5, 100, and 89.2%, respectively. The rates of malignancies belonging to categories 1, 2, 3, and 4 of the BI-RADS were 0, 0, 4.8, and 57.1%, respectively. CONCLUSIONS: The diagnostic performance of screening AB-MRI for women with a history of breast cancer surgery is acceptable, with the advantages of short examination and interpretation times and low costs. Thus, it could be used as a main screening modality that may replace conventional imaging in breast cancer survivors.

Correction to: Usefulness of abbreviated breast MRI screening for women with a history of breast cancer surgery.

In the original publication of the article, the acknowledgment section was missed out inadvertently. The acknowledgement section is below.

Adjunctive Breast-Specific Gamma Imaging for Detecting Cancer in Women with Calcifications at Mammography.

BACKGROUND: Mammography detects calcium deposits sensitively, but the specificity for differentiating malignancy from benign calcifications is low. Thus, we investigated whether adjunctive breast-specific gamma imaging (BSGI) has incremental value for detecting cancer in women with suspicious calcifications detected by mammography, and compared BSGI with adjunctive ultrasonography (US). METHODS: The medical records of women without a personal history of breast cancer who underwent mammography for breast evaluation from 2009 to 2014 were reviewed retrospectively. Patients who had calcifications detected by mammography, with a result of Breast Imaging Reporting and Data System (BI-RADS) categories 3-5, underwent adjunctive US and BSGI and were included in this study. A total of 302 breast lesions in 266 women (mean age ± standard deviation 49 ± 9 years) were selected for this study. RESULTS: For detecting breast cancer using mammography plus BSGI, the sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating curve with 95% confidence intervals were 94% (91-96), 90% (86-93), 91% (87-94), 94% (90-96), and 0.92 (0.89-0.95), respectively. For mammography plus US, the respective values were 97% (94-98), 51% (46-57), 68% (63-73), 94% (90-96), and 0.74 (0.70-0.78). CONCLUSIONS: Adjunctive BSGI had higher specificity than adjunctive US without loss of sensitivity. This finding suggests that adjunctive BSGI may be a useful complementary initial imaging method to improve the detection of breast cancer in women who have calcifications with suspicious morphology at mammography.

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.

Screening mammography-detected ductal carcinoma in situ: mammographic features based on breast cancer subtypes.

We evaluated the mammographic and histopathologic features of screening mammography-detected ductal carcinoma in situ (DCIS) based on the breast cancer subtypes determined by immunohistochemistry. A total of 94 patients with 94 screening mammography-detected DCIS were included in this study. Mammographically, human epidermal growth factor receptor 2 (HER2)-positive DCIS was more commonly associated with calcifications than estrogen receptor (ER)-positive and triple-negative DCIS (P=.003). Histopathologically, HER2-positive DCIS and triple-negative DCIS were associated with high nuclear grade (P ≤ .001) and comedo necrosis (P ≤ .001) than ER-positive DCIS.

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.

False positive or negative results of shear-wave elastography in differentiating benign from malignant breast masses: analysis of clinical and ultrasonographic characteristics.

BACKGROUND: Shear-wave elastography (SWE) has the potential to improve diagnostic performance of conventional ultrasound (US) in differentiating benign from malignant breast masses. PURPOSE: To investigate false positive or negative results of SWE in differentiating benign from malignant breast masses and to analyze clinical and imaging characteristics of the masses with false SWE findings. MATERIAL AND METHODS: From May to October 2013, 166 breast lesions of 164 consecutive women (mean age, 45.3 ± 10.1 years) who had been scheduled for biopsy were included. Conventional US and SWE were performed in all women before biopsy. Clinical, ultrasonographic morphologic features and SWE parameters (pattern classification and standard deviation [SD]) were recorded and compared with the histopathology results. Patient and lesion factors in the "true" and "false" groups were compared. RESULTS: Of the 166 masses, 118 (71.1%) were benign and 48 (28.9%) were malignant. False SWE features were more frequently observed in benign masses. False positive rates of benign masses and false negative rates of malignancy were 53% and 8.2%, respectively, using SWE pattern analysis and were 22.4% and 10.3%, respectively, using SD values. A lesion boundary of the masses on US (P = 0.039) and younger patient age (P = 0.047) were significantly associated with false SWE findings. CONCLUSION: These clinical and ultrasonographic features need to be carefully evaluated in performance and interpretation of SWE examinations.

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 < 0.001). The post-camp test scores were higher than the pre-camp test scores for all age groups and all types of attending institutions (p < 0.001). The rate of incorrect answers in the post-camp test decreased compared to the pre-camp test for all suspicious cases, but not for negative cases (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.

T1-T2 breast cancer with nodal metastasis: characteristics of pN2 or higher disease compared to pN1 disease.

AIM: The objective of the present study was to evaluate the clinical and imaging characteristics of T1-T2 breast cancer with nodal metastasis and compare these features of pN2 or higher disease against those of pN1 disease. PATIENTS AND METHODS: The mammographic, ultrasonographic and magnetic resonance imaging MRI features of 163 patients with T1-T2 cancer and nodal metastasis were retrospectively reviewed by two radiologists in consensus and compared between pN1 and pN2, or higher disease. Their clinical features were also compared. RESULTS: T1-T2 cancer with pN2 or higher disease is more likely to present with pleomorphic or linear-branching calcifications (p=0.003) on mammography and have non-parallel orientation on ultrasonography (p=0.008). Invasive tumor size larger than 2 cm (p=0.032), high histological grade (p=0.002) and lymphovascular invasion (p=0.009) were significantly associated with pN2 or higher disease. CONCLUSION: Being familiar with the imaging characteristics of T1-T2 cancer with nodal metastasis may be helpful in preoperatively evaluating the extent of nodal disease.

Complementary role of semiquantitative analysis of breast-specific gamma imaging in the diagnosis of breast cancer.

OBJECTIVE: We investigated whether the interpretation of breast-specific gamma imaging (BSGI) with visual and semiquantitative analyses can improve the diagnosis of breast cancer. MATERIALS AND METHODS: The records of 114 women (mean age±SD, 49.6±9.8 years) who underwent BSGI, mammography, and ultrasound to evaluate a breast lesion or lesions were reviewed retrospectively. The breast lesions identified with BSGI were compared with those identified with mammography and ultrasound. BSGI was first interpreted visually, and then a semiquantitative analysis was performed. For the semiquantitative analysis, the uptake ratio for each breast lesion was calculated by dividing the tumor uptake by the contralateral normal breast uptake. RESULTS: Four of the 114 patients had two breast lesions, so a total of 118 breast lesions (42 malignant lesions and 76 benign lesions) were evaluated. A BSGI uptake ratio cutoff of 1.5, with values less than 1.5 indicating negative for cancer, as determined by receiver operating characteristic curve analysis of our data (area under curve, 0.874), was used for semi-quantitative analysis. The sensitivity and specificity of BSGI with visual analysis alone for assessing malignant breast lesions were 76.2% (32/42) and 81.6% (62/76), respectively. For BSGI with visual and semiquantitative analyses, the sensitivity and specificity were 76.2% (32/42) and 92.1% (70/76), respectively. The sensitivity and specificity for mammography were 57.1% (24/42) and 81.6% (62/76), respectively. For ultrasound, the respective values were 97.6% (41/42) and 61.8% (47/76). BSGI with visual and semiquantitative analyses had a significantly higher specificity than BSGI with visual analysis alone, mammography, and ultrasound (all, p<0.01). CONCLUSION: Semiquantitative analysis of BSGI with visual interpretation may be a useful complementary method for evaluating malignant breast lesions.

Background uptake of breast-specific gamma imaging: correlation with mammographic breast density and background enhancement of breast MRI.

PURPOSE: To investigate the relationship between background uptake of breast-specific gamma imaging (BSGI) mammographic breast density and background enhancement of breast magnetic resonance imaging (MRI). MATERIALS AND METHODS: The level and texture of background uptake of BSGI, mammographic breast density, and background enhancement of breast MRI are retrospectively reviewed in 104 patients. RESULTS: Heterogeneous and increased background uptake of BSGI was significantly correlated with high mammographic breast density (P=.016, P=.001) and increased background enhancement of breast MRI (P=.015, P=.017). CONCLUSION: Interpreting BSGI of women showing high mammographic breast density or background enhancement of breast MRI needs to be carried out with caution.

Mammographic and ultrasonographic features of triple-negative breast cancer: a comparison with other breast cancer subtypes.

BACKGROUND: Triple-negative breast cancer (TNBC) is known to be associated with aggressive biologic features and a poor clinical outcome. Therefore, early detection of TNBC without missing cancer is mandatory to improve prognosis. PURPOSE: To retrospectively evaluate the mammographic and sonographic features of TNBC compared to ER (+) cancers and HER2 (+) cancers. MATERIAL AND METHODS: From June 2011 through June 2012, mammographic and sonographic features of 281 surgically confirmed ER (+) cancers (n = 153), HER2 (+) cancers (n = 83), and TNBC (n = 45) were retrospectively reviewed by two radiologists in consensus. The clinicopathological features were also compared between the three subtypes. Additionally the 45 TNBC cases were analyzed using morphologic criteria of ACR BI-RADS lexicon. RESULTS: Most TNBC (93.3%, 42 of 45) were mammographically seen and presented with mass or focal asymmetry without microcalcifications (P < 0.001). Ultrasonographically TNBC were presented as hypoechoic nodule without microcalcifications (P < 0.001). Palpable symptom (P < 0.001), a lower incidence of ductal carcinoma in situ (P < 0.001), invasive tumor size that is >2 cm (P = 0.028) and high histologic grade (P < 0.001) were significantly associated with TNBC. With regard to morphologic features of 45 TNBC cases, TNBC were most likely to be hyperdense mass (89.3%) with oval (68.9%) or lobular shape (28.6%) and indistinct (42.9%) or circumscribed margin (32.1%) on mammogram. Ultrasonographically TNBC were most likely to be a hypoechoic mass (82.2%) with irregular (68.9%) or oval (28.9%) shape and microlobulated (46.7%), circumscribed (17.8%) or indistinct margin (17.8%) and parallel orientation (68.9%). CONCLUSION: Being familiar with combined mammographic and ultrasonographic features of TNBC may be useful to avoid false-negative cases of TNBC.

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.

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.