2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1–2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Erratum: US-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: Efficacy and Safety in a Large Population

The publisher and authors would like to draw the reader’s attention to an error in the following article. The author name of “Seon Mi Baek” should be changed to “Sun Mi Baek”.

Ethanol Ablation of the Thyroid Nodules: 2018 Consensus Statement by the Korean Society of Thyroid Radiology

Minimally invasive treatment of symptomatic thyroid nodules is now commonplace. Ethanol ablation (EA) of thyroid cystic nodules has been performed since the 1990s, but there is no global consensus or guideline. Although various limitations of EA have been described, recommendations for practical application are necessary. Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology initiated the present consensus statement and here we provide recommendations for the role of EA in the management of symptomatic thyroid nodules. These recommendations are based on evidence to date from the literature and expert opinion.

US-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: Efficacy and Safety in a Large Population

OBJECTIVE: To evaluate the efficacy and safety of radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) in a large population.MATERIALS AND METHODS: Cases of 152 biopsy-proven PTMCs from 133 patients who had undergone RFA for PTMC between May 2008 and January 2017 were included in this study. All patients were either of high surgical risk or refused to undergo surgery. They were followed up for at least 6 months after initial RFA. Ultrasonography (US) and computed tomography were performed to evaluate the PTMC and the presence of neck metastasis before treatment. RFA was conducted using an internally cooled thyroid-dedicated electrode system. Follow-up US was performed at 1 week, and 2, 6, and 12 months, after the initial RFA, and then at every 6–12 months. We evaluated serial changes of ablated tumors, newly developed cancers, lymph node (LN) or distant metastasis and complications.RESULTS: Complete disappearance was found in 91.4% (139/152) of ablated tumors. Among the 13 tumors in patients who did not show complete disappearance, no tumor displayed any regrowth of the residual ablated lesion during the follow-up period. The mean follow-up period was 39 months. During the follow-up period, there were no local recurrence, no LN or distant metastasis, and no newly developed thyroid cancers. No patients were referred to surgery. The overall complication rate was 3% (4/133) of patients, including one voice change. There were no life-threatening complications or procedure-related deaths.CONCLUSION: Our results suggest that RFA is an effective and safe option for treating low-risk PTMC patients who are of high surgical risk or refuse surgery.

Summary of the 2017 thyroid radiofrequency ablation guideline and comparison with the 2012 guideline

Radiofrequency ablation (RFA) is a new, minimally invasive modality that serves as an alternative to surgery in patients with thyroid tumors. The Task Force Committee of the Korean Society of Thyroid Radiology developed recommendations for the optimal use of RFA for thyroid tumors in 2012 and revised them in 2017. Herein, we review and summarize the 2017 thyroid RFA guideline and compare it with the 2012 thyroid RFA guideline.

Craniopharyngioma with Intratumoral Hemorrhage and Superficial Siderosis

Superficial siderosis of the central nervous system (CNS) is a progressive and debilitating neurological disease manifesting sensorineural hearing loss, cerebellar ataxia, and pyramidal tract signs. Chronic extravasation of blood into the subarachnoid space results in the accumulation of hemoglobin derivate in the subpial layer of the CNS, which is toxic to the neural tissues. Craniopharyngioma is a benign third ventricle tumor, which rarely presents with tumor bleeding. We report a rare case of superficial siderosis associated with craniopharyngioma with intratumoral hemorrhage in a patient with no history of prior trauma or CNS surgery.

Primary Imaging Test and Appropriate Biopsy Methods for Thyroid Nodules: Guidelines by Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency

The Korean Society of Radiology and the National Evidence-based Healthcare Collaborating Agency developed guidelines for primary imaging tests and appropriate biopsy methods for thyroid nodules. These guidelines were developed using an adaptation process by collaboration between the development committee and the working group. The development committee, composed of research methodology experts, established the overall plan and provided support about methodological strategies. The working group, composed of radiologist experts in thyroid imaging, wrote the proposals. The guidelines recommend neck ultrasound (US) as a first-line imaging modality for the diagnosis of thyroid nodules in patients with suspected nodules, and US-guided fine-needle aspiration as a primary method for histologic examination of thyroid nodules.

2017 Thyroid Radiofrequency Ablation Guideline: Korean Society of Thyroid Radiology

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology (KSThR) developed recommendations for the optimal use of radiofrequency ablation for thyroid tumors in 2012. As new meaningful evidences have accumulated, KSThR decided to revise the guidelines. The revised guideline is based on a comprehensive analysis of the current literature and expert consensus.

Guidelines for Primary Imaging Test and Biopsy Methods in the Diagnosis of Thyroid Nodules: Joint Report by the Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency

The Korean Society of Radiology and the National Evidence-based Healthcare Collaborating Agency developed the guideline for primary imaging and biopsy methods in the diagnosis of thyroid nodules. The development committee, the working committee, and the advisory committee were formed to develop the recommendation. The development committee mainly plays a role of methodological consulting and overall planning and management of the advisory development stage. The working committee was composed of experts recommended by the Korean Society of Thyroid Radiology and conducted a practical adaptation process from the selection of core questions to the final recommendation. The Advisory Committee consisted of clinical experts recommended by the Korean Thyroid Association and reviewed core questions and draft recommendations and participated in the Expert Panel Survey. This guideline recommends cervical ultrasound as the first imaging modality for diagnosis of suspected thyroid nodules and recommends ultrasound-guided fine needle aspiration for histologic diagnosis of thyroid nodules. This guideline is expected to be of significant benefit to clinicians treating thyroid nodules.

Erratum: Guidelines for Primary Imaging Test and Biopsy Methods in the Diagnosis of Thyroid Nodules: Joint Report by the Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency

The publisher and authors would like to draw the reader’s attention to an error and revised “Figure 8”.

Estimation of Diastolic Filling Pressure with Cardiac CT in Comparison with Echocardiography Using Tissue Doppler Imaging: Determination of Optimal CT Reconstruction Parameters

OBJECTIVE: To determine the optimal CT image reconstruction parameters for the measurement of early transmitral peak velocity (E), early peak mitral septal tissue velocity (E′), and E / E′. MATERIALS AND METHODS: Forty-six patients underwent simultaneous cardiac CT and echocardiography on the same day. Four CT datasets were reconstructed with a slice thickness/interval of 0.9/0.9 mm or 3/3 mm at 10 (10% RR-interval) or 20 (5% RR-interval) RR-intervals. The E was calculated by dividing the peak transmitral flow (mL/s) by the corresponding mitral valve area (cm²). E′ was calculated from the changes in the left ventricular length per cardiac phase. E / E′ was then estimated and compared with that from echocardiography. RESULTS: For assessment of E / E′, CT and echocardiography were more strongly correlated (p < 0.05) with a slice thickness of 0.9 mm and 5% RR-interval (r = 0.77) than with 3 mm or 10% RR-interval. The diagnostic accuracy of predicting elevated filling pressure (E / E′≥ 13, n = 14) was better with a slice thickness of 0.9 mm and 5% RR-interval (87.0%) than with 0.9 mm and 10% RR-interval (71.7%) (p = 0.123) and significantly higher than that with a slice thickness of 3 mm with 5% (67.4%) and 10% RR-interval (63.0%), (p < 0.05), respectively. CONCLUSION: Data reconstruction with a slice thickness of 0.9 mm at 5% RR-interval is superior to that with a slice thickness of 3 mm or 10% RR-interval in terms of the correlation of E / E′ between CT and echocardiography. Thin slices and frequent sampling also allow for more accurate prediction of elevated filling pressure.

Establishing a colorectal cancer liver metastasis patient-derived tumor xenograft model for the evaluation of personalized chemotherapy

PURPOSE: In order to suggest optimal anticancer drugs for patient-tailored chemotherapy, we developed a colorectal cancer (CRC)-liver metastasis patient-derived tumor xenograft (PDTX) model. METHODS: Tissue obtained from a patient with CRC-liver metastasis (F0) was transplanted in a nonobese female mouse with diabetic/severe combined immune deficiency (F1) and the tumor tissue was retransplanted into nude mice (F2). When tumor volumes reached ~500 mm³, the F2 mice were randomly divided into 4 groups (n = 4/group) of doxorubicin, cisplatin, docetaxel, and nontreated control groups. The tumor tissues were investigated using H&E staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assays, and immunohistochemistry. To determine where the mutant allele frequencies varied across the different passages, we isolated genomic DNA from the primary tumor, liver metastasis, and PDTX models (F1/F2). RESULTS: The physiological properties of the tumor were in accord with those of the patient's tumors. Anticancer drugs delayed tumor growth, inhibited proliferation, and caused apoptosis. Histological assessments revealed no observable heterogeneity among the intragenerational PDTX models. Target exon sequencing analysis without high-quality filter conditions revealed some genetic variations in the 83 cancer-related genes across the generations. However, when de novo mutations were defined as a total count of zero in F0 and ≥5 in F2, exactly prognostic impact of clone cancer profiling (EGFR, KRAS, BRAF, PIK3CA, NRAS, APC and TP53) were detected in the paired. CONCLUSION: A CRC liver metastasis PDTX model was established for the evaluation of chemotherapeutic efficacy. This model retained the physiological characters of the patient tumors and potentially provides a powerful means of assessing chemotherapeutic efficacy.

Core Needle Biopsy of the Thyroid: 2016 Consensus Statement and Recommendations from Korean Society of Thyroid Radiology

Core needle biopsy (CNB) has been suggested as a complementary diagnostic method to fine-needle aspiration in patients with thyroid nodules. Many recent CNB studies have suggested a more advanced role for CNB, but there are still no guidelines on its use. Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology has developed the present consensus statement and recommendations for the role of CNB in the diagnosis of thyroid nodules. These recommendations are based on evidence from the current literature and expert consensus.

Ultrasonography Diagnosis and Imaging-Based Management of Thyroid Nodules: Revised Korean Society of Thyroid Radiology Consensus Statement and Recommendations

The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.

Comparison between Ultrasonography and Computed Tomography for Detecting the Pyramidal Lobe of the Thyroid Gland: A Prospective Multicenter Study

OBJECTIVE: To compare the detection rates of the pyramidal lobe of the thyroid gland (TPL) using ultrasonography (US) and computed tomography (CT) in a prospective multi-center study. MATERIALS AND METHODS: We enrolled 582 patients who underwent neck CT at six institutions. Each radiologist prospectively evaluated the presence and features of TPLs on thyroid US. Radiologists were divided into two groups according to their previous experience in detecting TPL on US or CT. The same radiologist also retrospectively assessed CT findings, blinded to the corresponding US findings. RESULTS: The pyramidal lobe of the thyroid glands were detected in 230 cases (39.5%) on US and in 276 cases (47.6%) on CT. The TPL detection rate at the six institutions ranged from 22.0% to 59% for US and from 34.1% to 59% using CT. There were significant differences between US and CT in the detection rate, length, anteroposterior diameter, volume, and superior extent of TPL (p < or = 0.027). The TPL detection rates on both US and CT (p < 0.001) differed significantly according to the experience level of the radiologists. When the CT result was used as a reference standard, the sensitivity, specificity, positive and negative predictive values, as well as the accuracy of US for TPL detection were 72.6%, 91.5%, 89.3%, 77.3%, and 82.1%, respectively. CONCLUSION: Our prospective multicenter study revealed that US could detect TPL with relatively high diagnostic accuracy compared to CT. Because the detection rate of TPL varied significantly according to the radiologists' level of experience, careful inspection is necessary to avoid imaging pitfalls and ensure appropriate evaluation of TPL on both US and CT.

Comparison of effects of intraoperative esmolol and ketamine infusion on acute postoperative pain after remifentanil-based anesthesia in patients undergoing laparoscopic cholecystectomy / 대한마취과학회지

BACKGROUND: Remifentanil is a short-acting drug with a rapid onset that is useful in general anesthesia. Recently, however, it has been suggested that the use of opioids during surgery may cause opioid-induced hyperalgesia (OIH). Researchers have recently reported that esmolol, an ultra-short-acing beta1 receptor antagonist, reduces the postoperative requirement for morphine and provides more effective analgesia than the administration of remifentanil and ketamine. Hence, this study was conducted to determine whether esmolol reduces early postoperative pain in patients who are continuously infused with remifentanil for anesthesia during laparoscopic cholecystectomy. METHODS: Sixty patients scheduled to undergo laparoscopic cholecystectomy were randomly divided into three groups. Anesthesia was maintained with sevoflurane and 4 ng/ml (target-controlled infusion) of remifentanil in all patients. Esmolol (0.5 mg/kg) was injected and followed with a continuous dosage of 10 microg/kg/min in the esmolol group (n = 20). Ketamine (0.3 mg/kg) was injected and followed with a continuous dosage of 3 microg/kg/min in the ketamine group (n = 20), while the control group was injected and infused with an equal amount of normal saline. Postoperative pain score (visual analog scale [VAS]) and analgesic requirements were compared for the first 6 hours of the postoperative period. RESULTS: The pain score (VAS) and fentanyl requirement for 15 minutes after surgery were lower in the esmolol and ketamine groups compared with the control group (P < 0.05). There were no differences between the esmolol and ketamine groups. CONCLUSIONS: Intraoperative esmolol infusion during laparoscopic cholecystectomy reduced opioid requirement and pain score (VAS) during the early postoperative period after remifentanil-based anesthesia.

Endovascular Treatment of Isolated Bilateral Common Iliac Artery Aneurysms Using Iliac Branched Stent Graft

Endovascular treatment of isolated bilateral common iliac artery aneurysm (CIAA) requires salvage of at least one internal iliac artery to prevent complications such as ischemic buttock claudication. We treated a case of bilateral CIAAs using an internal iliac branched stent graft. We report a case of a 58-year-old man who presented with bilateral CIAAs. The left internal iliac artery was occluded with coil embolization. The right internal iliac artery was saved by using a branched stent graft. The aneurysms were excluded with conventional endovascular aneurysm repair. Completion angiography showed technical success. Follow up computed tomography angiogram at three months showed complete exclusion of bilateral CIAAs, no endoleaks, and patent right internal iliac artery. There was no pelvic ischemic complication. We treated successfully a case of isolated bilateral CIAAs using an iliac branched stent graft.

Is Diffusion-Weighted MRI Useful for Differentiation of Small Non-Necrotic Cervical Lymph Nodes in Patients with Head and Neck Malignancies?

OBJECTIVE: To evaluate the usefulness of measuring the apparent diffusion coefficient (ADC) in diffusion-weighted magnetic resonance imaging to distinguish benign from small, non-necrotic metastatic cervical lymph nodes in patients with head and neck cancers. MATERIALS AND METHODS: Twenty-six consecutive patients with head and neck cancer underwent diffusion-weighted imaging (b value, 0 and 800 s/mm2) preoperatively between January 2009 and December 2010. Two readers independently measured the ADC values of each cervical lymph node with a minimum-axial diameter of > or = 5 mm but < 11 mm using manually drawn regions of interest. Necrotic lymph nodes were excluded. Mean ADC values were compared between benign and metastatic lymph nodes after correlating the pathology. RESULTS: A total of 116 lymph nodes (91 benign and 25 metastatic) from 25 patients were included. Metastatic lymph nodes (mean +/- standard deviation [SD], 7.4 +/- 1.6 mm) were larger than benign lymph nodes (mean +/- SD, 6.6 +/- 1.4 mm) (p = 0.018). Mean ADC values for reader 1 were 1.17 +/- 0.31 x 10-3 mm2/s for benign and 1.25 +/- 0.76 x 10-3 mm2/s for metastatic lymph nodes. Mean ADC values for reader 2 were 1.21 +/- 0.46 x 10-3 mm2/s for benign and 1.14 +/- 0.34 x 10-3 mm2/s for metastatic lymph nodes. Mean ADC values between benign and metastatic lymph nodes were not significantly different (p = 0.594 for reader 1, 0.463 for reader 2). CONCLUSION: Measuring mean ADC does not allow differentiating benign from metastatic cervical lymph nodes in patients with head and neck cancer and non-necrotic, small lymph nodes.

Core Needle Biopsy of Thyroid Nodules: Consensus Statement and Recommendations

Core needle biopsy is a complementary diagnostic method of fine needle aspiration for patients with thyroid nodules. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for diagnosis of thyroid nodules and recurrent thyroid cancers using core needle biopsy. These recommendations are based on evidence from the current literature and expert consensus.

Ultrasonographic Evaluation of Acute Appendicitis Superimposed on the Non-rotational Anomaly of the Gastrointestinal Tract

We report on the case of a 29-year-old male with acute appendicitis superimposed on the non-rotational anomaly of the gastrointestinal tract not detected on the computed tomography (CT) scan but correctly diagnosed on ultrasonography (US). This case suggested an additional role of US on the acute abdomen even underlying malrotation of the gastrointestinal tract.