Korean Journal of Radiology最新文献

External beam radiation therapy (RT) can induce toxicity in patients surgically treated for breast cancer. Modern irradiation techniques have lowered the incidence and severity of radiation-induced injuries; however, their side effects on normal tissues remain challenging. This review illustrates early and late changes observed using ultrasound (US) imaging, including echocardiography, at the skin, muscle, pleura, lungs, and heart levels. The US findings and the potential role of this technique in detecting and grading early and late complications of RT are highlighted in this article. US has proven useful in the differential diagnosis of post-RT complications, including but not limited to cancer recurrence and toxicity from other sources, such as anticancer drugs. Additionally, considering the progressive nature of RT-induced injury, early detection of toxicity may be helpful in the individual stratification of damage risk and serve as a tool for patient screening and management. In these cases, US can be used as a radiation-free biomarker of RT side effects at the subclinical stage.

Generative artificial intelligence (AI) has been applied to images for image quality enhancement, domain transfer, and augmentation of training data for AI modeling in various medical fields. Image-generative AI can produce large amounts of unannotated imaging data, which facilitates multiple downstream deep-learning tasks. However, their evaluation methods and clinical utility have not been thoroughly reviewed. This article summarizes commonly used generative adversarial networks and diffusion models. In addition, it summarizes their utility in clinical tasks in the field of radiology, such as direct image utilization, lesion detection, segmentation, and diagnosis. This article aims to guide readers regarding radiology practice and research using image-generative AI by 1) reviewing basic theories of image-generative AI, 2) discussing the methods used to evaluate the generated images, 3) outlining the clinical and research utility of generated images, and 4) discussing the issue of hallucinations.

Objective: To assess the role of dynamic contrast-enhanced (DCE)-MRI of the extraocular muscles (EOMs) for determining the activity of thyroid-associated ophthalmopathy (TAO) and treatment response to glucocorticoids (GCs).

Materials and methods: We prospectively enrolled 65 patients with TAO (41 active, 82 eyes; 24 inactive, 48 eyes). Twenty-two active patients completed the GC treatment and follow-up assessment, including 15 patients (30 eyes) and 7 patients (14 eyes), defined as responsive and unresponsive, respectively. Model-free (time to peak [TTP], area under the curve [AUC], and Slope_max) and model-based (K^trans, K_ep, and V_e) parameters of EOMs in embedded simplified histogram analyses were calculated and compared between groups. Multivariable logistic regression analysis was used to identify the independent predictors. The area under the receiver operating characteristic curve (AUROC) was used to evaluate the diagnostic performance.

Results: Active patients exhibited significantly higher TTP at the 10th percentile (-10th), TTP-mean, and TTP at the 90th percentile (-90th); AUC-10th, AUC-mean, AUC-90th, and AUC-max; K^trans-10th and K^trans-mean; and V_e-10th, V_e-mean, V_e-90th, and V_e-max than inactive patients (P < 0.05). Responsive patients exhibited significantly lower TTP-min; higher K^trans-mean and K^trans-max; and higher K_ep-10th, K_ep-mean, and K_ep-max than unresponsive patients (P < 0.05). TTP-mean and V_e-mean were independent variables for determining disease activity (P = 0.017 and 0.022, respectively). A combination of the two parameters could determine active TAO with moderate performance (AUROC = 0.687). TTP-min and K^trans-mean were independent predictors of the response to GCs (P = 0.023 and 0.004, respectively), uniting which could determine the response to GCs with decent performance (AUROC = 0.821).

Conclusion: DCE-MRI-derived model-free and model-based parameters of EOMs can assist in the evaluation of TAO. In particular, TTP-mean and V_e-mean could be useful for determining the activity of TAO, whereas TTP-min and K^trans-mean could be promising biomarkers for determining the response to GCs.

Objective: To develop a nomogram that integrates clinical-pathologic and imaging variables to predict ipsilateral breast tumor recurrence (IBTR) in women with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (BCS).

Materials and methods: This retrospective study included consecutive women with DCIS who underwent BCS at two hospitals. Patients who underwent BCS between 2003 and 2016 in one hospital and between 2005 and 2013 in another were classified into development and validation cohorts, respectively. Twelve clinical-pathologic variables (age, family history, initial presentation, nuclear grade, necrosis, margin width, number of excisions, DCIS size, estrogen receptor, progesterone receptor, radiation therapy, and endocrine therapy) and six mammography and ultrasound variables (breast density, detection modality, mammography and ultrasound patterns, morphology and distribution of calcifications) were analyzed. A nomogram for predicting 10-year IBTR probabilities was constructed using the variables associated with IBTR identified from the Cox proportional hazard regression analysis in the development cohort. The performance of the developed nomogram was evaluated in the external validation cohort using a calibration plot and 10-year area under the receiver operating characteristic curve (AUROC) and compared with the Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram.

Results: The development cohort included 702 women (median age [interquartile range], 50 [44-56] years), of whom 30 (4%) women experienced IBTR. The validation cohort included 182 women (48 [43-54] years), 18 (10%) of whom developed IBTR. A nomogram was constructed using three clinical-pathologic variables (age, margin, and use of adjuvant radiation therapy) and two mammographic variables (breast density and calcification morphology). The nomogram was appropriately calibrated and demonstrated a comparable 10-year AUROC to the MSKCC nomogram (0.73 vs. 0.66, P = 0.534) in the validation cohort.

Conclusion: Our nomogram provided individualized risk estimates for women with DCIS treated with BCS, demonstrating a discriminative ability comparable to that of the MSKCC nomogram.

Objective: To prospectively compare single-shot (SS) echo-planar imaging (EPI) and field-of-view optimized and constrained undistorted single-shot multiplexed sensitivity-encoding (FOCUS MUSE) for diffusion-weighted imaging (DWI) in evaluating thyroid-associated ophthalmopathy (TAO).

Materials and methods: SS EPI and FOCUS MUSE DWIs were obtained from 39 patients with TAO (18 male; mean ± standard deviation: 48.3 ± 13.3 years) and 26 healthy controls (9 male; mean ± standard deviation: 43.0 ± 18.5 years). Two radiologists scored the visual image quality using a 4-point Likert scale. The image quality score, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) of extraocular muscles (EOMs) were compared between the two DWIs. Differences in the ADC of EOMs were also evaluated. The performance of discriminating active from inactive TAO was assessed using receiver operating characteristic curves. The correlation between ADC and clinical activity score (CAS) was analyzed using Spearman correlation.

Results: Compared with SS EPI DWI, FOCUS MUSE DWI demonstrated significantly higher image quality scores (P < 0.001), a higher SNR and CNR on the lateral rectus muscle (LRM) and medial rectus muscle (MRM) (P < 0.05), and a non-significant difference in the ADC of the LRM and MRM. Active TAO showed higher ADC than inactive TAO and healthy controls with both SS EPI and FOCUS MUSE DWIs (P < 0.001). Inactive TAO and healthy controls did not show a significant ADC difference with both DWIs. Compared with SS EPI DWI, FOCUS MUSE DWI demonstrated better discrimination of active from inactive TAO (AUC: 0.925 vs. 0.779; P = 0.007). The ADC was significantly correlated with CAS in SS EPI DWI (r = 0.391, P < 0.001) and FOCUS MUSE DWI (r = 0.645, P < 0.001).

Conclusion: FOCUS MUSE DWI provides better images for evaluating EOMs and better performance in diagnosing active TAO than SS EPI DWI. The application of FOCUS MUSE will facilitate the DWI evaluation of TAO.

Objective: This study aimed to evaluate the performance of an integrated risk stratification system (RSS) based on ultrasound (US) RSSs, nodule size, and cytology subcategory for diagnosing malignancy in thyroid nodules initially identified as Bethesda category III on fine-needle aspiration.

Materials and methods: This retrospective study was conducted at two institutions and included consecutive patients with Bethesda category III nodules, and final diagnoses confirmed by repeat biopsy or surgery. A total of 320 Bethesda category III nodules (≥1 cm) from 309 patients (223 female and 86 male; mean age, 50.9 ± 12.0 years) were included. The malignancy risk of Bethesda category III nodules and predictors of malignancy were assessed according to US RSSs, nodule size, and cytology subcategory. The diagnostic performances of US-size cytology (USC) RSS and US RSS alone for malignancy were compared.

Results: The intermediate or high suspicion US category independently increased the malignancy risk in all US RSSs (P ≤ 0.001). Large nodule size (≥3 cm) independently increased the malignancy risk of low- or intermediate suspicion US category nodules. Additionally, the atypia of undetermined significance cytology subcategory independently increased the malignancy risk of low suspicion US category nodules in most US RSSs. The area under the receiver operating characteristic curve of the USC RSSs was greater than that of the US RSSs alone (P < 0.048). Malignancy was not found in the very low risk category of USC RSS.

Conclusion: The diagnostic performance of USC RSS for malignancy was superior to that of US RSS alone in Bethesda category III nodules. Malignancy can be ruled out in the very low-risk category of USC RSS.