Superficial Radial Neuropathy due to Anatomic Variation: A Case Report.

Superficial radial neuropathy is a purely sensory neuropathy, usually caused by nerve entrapment in the distal forearm. We report a case of superficial radial neuropathy caused by the anomalous course of the superficial radial nerve, which was found to be spirally encircling the brachioradialis tendon in the distal forearm. To the best of our knowledge, this is the first report of an anatomical variant of the superficial radial nerve that causes neuropathy.

Unusual Manifestation of Immunoglobulin G4-Related Disease Involving the Upper Arm: A Case Report.

Immunoglobulin G4 (IgG4)-related disease is a rare systemic fibroinflammatory condition characterized by organomegaly or tumefactive lesions associated with lymphoplasmacytic infiltration rich in IgG4 plasma cells. We report a case of IgG4-related disease involving the subcutaneous layer of the left upper arm in a 48-year-old female presenting with an unusual soft tissue mass. US and MRI showed an irregular infiltrative soft tissue mass, indicating possible malignancy or inflammation. We discuss the diagnostic criteria, histopathologic features, radiological features, and treatment of IgG4-related disease.

Diffuse Large B-Cell Lymphoma Associated with a Chronic Inflammatory Condition Induced by Metallic Implants: A Case Report.

Chronic inflammatory condition associated with metallic implant insertion is a risk factor for diffuse large B-cell lymphoma (DLBCL). Metal ions play a role in the pathogenesis of lymphoma. We report a rare case of DLBCL in a patient who had a metallic implant in the proximal tibia for 15 months. Radiologic studies, including US and MRI, showed disproportionately large extraosseous soft-tissue mass and bone marrow involvement without prominent bone destruction. Multiple complications are associated with metallic implants, and misdiagnosis may lead to inappropriate treatment. Therefore, distinguishing lymphomas caused by a metallic implant-induced chronic inflammatory condition from other periprosthetic benign lesions and malignant soft tissue masses is challenging, but it is critical.

Comparison of MR Findings between Patients with Septic Arthritis and Acute Gouty Arthritis of the Knee.

Purpose: To compare the MR findings of septic and acute gouty arthritis of the knee joint. Materials and Methods: This retrospective study included patients who underwent knee MRI for septic or gouty arthritis at our hospital between October 2012 and October 2018. The MR findings were analyzed for the presence of bone marrow edema, soft tissue edema, abscess, pattern of synovial thickening (frondlike, lamellated, diffuse linear), maximum thickness of the synovium, and joint effusion volume. The gouty (n = 5) and septic arthritis (n = 10) groups were compared using the Wilcoxon rank-sum test and Fisher's exact test. Results: No statistically significant differences were observed for each item. One patient in the gouty arthritis group and seven in the septic arthritis group had bone marrow edema. Soft tissue abscess formation was only observed in the septic group. The incidence of each synovial thickening pattern was as follows: 100% (diffuse linear) in the gouty arthritis group and 20% (frondlike), 50% (lamellated), and 30% (diffuse linear) in the septic arthritis group. Conclusion: Differentiation of gouty arthritis and septic arthritis based on imaging findings is difficult. However, lamellated synovial thickening patterns, bone marrow edema, and soft tissue abscess formation are more commonly observed in patients with septic arthritis than in those with gouty arthritis.

Is Free Breathing Possible During Computed Tomography-Guided Percutaneous Transthoracic Lung Biopsy? The Clinical Experience in 585 Cases.

OBJECTIVE: The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing. METHODS: We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis. RESULTS: Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P < 0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P < 0.001), lower lobe location (P < 0.001), prone position (P = 0.004), and visible motion artifact (P < 0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P < 0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P < 0.001) were risk factors for hemoptysis. CONCLUSIONS: Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

Risk factors and screening timing for developmental dysplasia of the hip in preterm infants.

BACKGROUND: The delayed diagnosis of developmental dysplasia of the hip (DDH) requires complex treatment and sometimes progresses to hip osteoarthritis. PURPOSE: This study aimed to evaluate the risk factors and screening time for DDH in preterm infants. METHODS: A total of 155 preterm infants with a gestational age <32 weeks screened for DDH with ultrasonography were enrolled in this retrospective chart review. RESULTS: The incidence of DDH was 6.45% (10 of 155). Gestational age, birth weight, sex ratio, and breech presentation did not differ significantly between infants treated for DDH (n=10) and nontreated infants (n=145) (gestational age, 29.2±1.4 weeks vs. 29.6±2.0 weeks, P=0.583; birth weight, 1,240±237 g vs. 1,295±335 g, P=0.607; female sex, 7 of 10 (70.0%) vs. 77 of 145 (53.1%), P=0.346; and breech presentation, 5 of 10 (50.0%) vs. 43 of 145 (29.7%), P=0.286, respectively). Performing the first ultrasonography earlier than 38 weeks of postmenstrual age (PMA) increased the risk of an abnormal finding by 3.76 times compared to performing it at ≥38 weeks of PMA. These abnormal findings on ultrasonography resolved spontaneously. Breech presentation increased the risk of minor abnormal findings on the first ultrasonography by 3.11 times versus nonbreech presentation and resolved spontaneously. DDH in preterm infants did not occur predominantly on the left side or in infants born with breech presentation. CONCLUSION: Performing ultrasonography screening earlier than 38 weeks of PMA caused unnecessary subsequent ultrasonography and overtreatment. Breech presentation was not a risk factor for DDH in preterm infants. However, breech presentation could increase the risk of minor abnormal findings at the 1st ultrasonography compared to nonbreech presentation, which resolved spontaneously. The etiology and risk factors for DDH in preterm infants are somewhat different from those for DDH in term infants.

Avulsion injuries: an update on radiologic findings.

Avulsion injuries result from the application of a tensile force to a musculoskeletal unit or ligament. Although injuries tend to occur more commonly in skeletally immature populations due to the weakness of their apophysis, adults may also be subject to avulsion fractures, particularly those with osteoporotic bones. The most common sites of avulsion injuries in adolescents and children are apophyses of the pelvis and knee. In adults, avulsion injuries commonly occur within the tendon due to underlying degeneration or tendinosis. However, any location can be involved in avulsion injuries. Radiography is the first imaging modality to diagnose avulsion injury, although advanced imaging modalities are occasionally required to identify subtle lesions or to fully delineate the extent of the injury. Ultrasonography has a high spatial resolution with a dynamic assessment potential and allows the comparison of a bone avulsion with the opposite side. Computed tomography is more sensitive for depicting a tiny osseous fragment located adjacent to the expected attachment site of a ligament, tendon, or capsule. Moreover, magnetic resonance imaging is the best imaging modality for the evaluation of soft tissue abnormalities, especially the affected muscles, tendons, and ligaments. Acute avulsion injuries usually manifest as avulsed bone fragments. In contrast, chronic injuries can easily mimic other disease processes, such as infections or neoplasms. Therefore, recognizing the vulnerable sites and characteristic imaging features of avulsion fractures would be helpful in ensuring accurate diagnosis and appropriate patient management. To this end, familiarity with musculoskeletal anatomy and mechanism of injury is necessary.

Comparison of the Quality of Various Polychromatic and Monochromatic Dual-Energy CT Images with or without a Metal Artifact Reduction Algorithm to Evaluate Total Knee Arthroplasty.

OBJECTIVE: To compare the quality of various polychromatic and monochromatic images with or without using an iterative metal artifact reduction algorithm (iMAR) obtained from a dual-energy computed tomography (CT) to evaluate total knee arthroplasty. MATERIALS AND METHODS: We included 58 patients (28 male and 30 female; mean age [range], 71.4 [61-83] years) who underwent 74 knee examinations after total knee arthroplasty using dual-energy CT. CT image sets consisted of polychromatic image sets that linearly blended 80 kVp and tin-filtered 140 kVp using weighting factors of 0.4, 0, and -0.3, and monochromatic images at 130, 150, 170, and 190 keV. These image sets were obtained with and without applying iMAR, creating a total of 14 image sets. Two readers qualitatively ranked the image quality (1 [lowest quality] through 14 [highest quality]). Volumes of high- and low-density artifacts and contrast-to-noise ratios (CNRs) between the bone and fat tissue were quantitatively measured in a subset of 25 knees unaffected by metal artifacts. RESULTS: iMAR-applied, polychromatic images using weighting factors of -0.3 and 0.0 (P-0.3i and P0.0i, respectively) showed the highest image-quality rank scores (median of 14 for both by one reader and 13 and 14, respectively, by the other reader; p < 0.001). All iMAR-applied image series showed higher rank scores than the iMAR-unapplied ones. The smallest volumes of low-density artifacts were found in P-0.3i, P0.0i, and iMAR-applied monochromatic images at 130 keV. The smallest volumes of high-density artifacts were noted in P-0.3i. The CNRs were best in polychromatic images using a weighting factor of 0.4 with or without iMAR application, followed by polychromatic images using a weighting factor of 0.0 with or without iMAR application. CONCLUSION: Polychromatic images combined with iMAR application, P-0.3i and P0.0i, provided better image qualities and substantial metal artifact reduction compared with other image sets.

CT Follow-Up of Postoperative Bronchopleural Fistula: Risk Factors for Progression to Chronic Complicated Infection.

Purpose: We evaluated the risk factors for progression to chronic complicated bronchopleural fistula (BPF) after pulmonary resection using follow-up CT. Materials and Methods: We retrospectively reviewed 45 cases with BPF that had undergone pulmonary resection during 2010-2018. We compared the clinical and radiological characteristics of those with complicated BPF (n = 24) and those without complicated (sterilized) BPF (n = 21). The clinical and radiological risk factors for progression to chronic complicated BPF were examined by logistic regression analysis. Results: The thickness of the pleural cavity wall (p = 0.022), the size of the pleural cavity (p = 0.029), and the size increase of BPF on follow-up (p = 0.012) were significantly different between the two groups. The risk factors for progression to chronic complicated BPF were age > 70 years (odds ratio, 6.43; 95% confidence interval, 1.2-33.7), the thickness of the cavity wall > 5 mm (odds ratio, 52.5; 95% confidence interval, 5.1-545.4), and an increase in the size of the pleural cavity on follow-up CT (odds ratio, 12.5; 95% confidence interval, 2.1-73.5), only in the univariate analysis. Conclusion: The risk factors for progression to chronic complicated BPF can be evaluated using follow-up CT.

Usefulness of pointwise encoding time reduction with radial acquisition sequence in subtraction-based magnetic resonance angiography for follow-up of the Neuroform Atlas stent-assisted coil embolization for cerebral aneurysms.

BACKGROUND: Although time-of-flight magnetic resonance angiography (TOF-MRA) is widely used, it has limited usefulness for follow-up after stent-assisted coil embolization. Contrast-enhanced MRA (CE-MRA) and ultrashort echo time MRA have been suggested as alternative methods for visualization after this procedure. PURPOSE: To compare efficacy and usefulness of pointwise encoding time reduction with radial acquisition (PETRA) sequence in subtraction-based MRA (qMRA), TOF-MRA, and CE-MRA during the follow-up after Neuroform Atlas stent-assisted coil embolization for intracranial aneurysms. MATERIAL AND METHODS: This retrospective study included 23 patients with 24 aneurysms who underwent Neuroform Atlas stent-assisted coil embolization for intracranial aneurysms. All patients were evaluated with PETRA qMRA, TOF-MRA, and CE-MRA at the same follow-up session. The flow within stents, occlusion status, and presence of pseudo-stenosis were evaluated; inter-observer and intermodality agreements for the three methods were also graded. RESULTS: The mean score for flow visualization within the stents was significantly higher for PETRA qMRA and CE-MRA than for TOF-MRA (although no significant difference was found between PETRA qMRA and CE-MRA). Good inter-observer agreement was observed for each modality. PETRA qMRA and CE-MRA were more consistent with digital subtraction angiography (DSA) than TOF-MRA for aneurysm occlusion status. The intermodality agreement was better between PETRA qMRA and DSA, and between CE-MRA and DSA, than between DSA and TOF-MRA. Pseudo-stenosis was most frequently observed in TOF-MRA, followed by CE-MRA and PETRA qMRA. CONCLUSION: PETRA qMRA is useful for evaluating the parent artery patency and occlusion status of aneurysms after Neuroform Atlas stent-assisted coil embolization.

Computed tomography arthrography of the shoulder with tin filter-based spectral shaping at 100 kV and 140 kV.

BACKGROUND: Tin filter-based spectral shaping has been used for low-dose and ultra-low-dose computed tomography (CT) in several body parts. However, studies of shoulder CT arthrography with spectral shaping are limited. PURPOSE: To investigate image quality and radiation dose of shoulder CT arthrography with tin filter-based spectral shaping at 100 kV (Sn 100 kV) and 140 kV (Sn 140 kV) in comparison with the conventional protocol. MATERIAL AND METHODS: Ninety-nine shoulder CT arthrographies with protocols of Sn 100 kV (n = 32), Sn 140 kV (n = 25), and conventional 120 kV (n = 42) were retrospectively evaluated. Qualitative image quality, CT attenuations of intra-articular contrast mixture and tissues, background noise, contrast-to-noise ratios (CNRs), and figures of merit were assessed. Radiation doses were compared. RESULTS: CT arthrographies with Sn 100 kV and Sn 140 kV yielded approximately 70% and 60% radiation dose reduction, respectively, compared with the conventional 120 kV (P < 0.001). Qualitative image noise and quantitative background noise of Sn 100 kV and Sn 140 kV were significantly less than those of the conventional protocol. Qualitative image contrast, CT attenuations of intra-articular contrast mixture and tissues, and CNRs for Sn 100 were similar to those of the conventional 120 kV. However, Sn 140 kV showed significantly lower qualitative contrast and CNRs than 120 kV. Sn 100 kV was the most dose efficient among the three protocols. CONCLUSION: Shoulder CT arthrography with Sn 100 kV substantially reduced radiation dose and image noise and maintained image contrast, compared with the conventional protocol.

Comparison of Ultrasonography Features and K-TIRADS for Isthmic and Lobar Papillary Thyroid Carcinomas: A Single-Center Study.

Objective: This study aimed to compare ultrasonography (US) features and the Korean-Thyroid Imaging Reporting and Data System (K-TIRADS) categories for diagnosing isthmic and lobar papillary thyroid carcinomas (PTC). Methods: From January 2009 to December 2012, 163 patients who underwent thyroid surgery and were confirmed with a post-operative histopathological diagnosis of isthmic PTC were retrospectively included. Fifty-nine patients were excluded because their tumor size was <0.5 cm or because of other reasons. The control group comprised of 145 patients who underwent thyroid surgery from January to April 2013 for a classic type of PTC, with the largest diameter being ≥ 0.5 cm and located in the thyroid lobe. A single radiologist retrospectively reviewed the US features and K-TIRADS categories of each nodule using a picture archiving and communication system. Results: Among 104 patients with isthmic PTC, 95 and 9 had primary and secondary cancers, respectively. On the other hand, all 145 patients with lobar PTC had primary cancers. Isthmic PTC showed a lower prevalence of non-parallel orientation than lobar PTC (23.1 and 71%). Nodule orientation was the only US feature statistically different between the two groups (p < 0.0001). However, there was no significant difference in patient age, sex, nodule size, composition, echogenicity, microcalcification, spiculated/microlobulated margin, and K-TIRADS category between the two groups (p > 0.05). Conclusions: K-TIRADS may be useful in the diagnosis of both isthmic and lobar PTC.

Prevalence and Features of Thyroglossal Duct Cyst on Ultrasonography, According to Radioactive Iodine Therapy: A Single-Center Study.

Objective: The relationship between radioactive iodine therapy (RIT) and prevalence of thyroglossal duct cysts (TGDC) on ultrasonography (US) has not been reported. We assessed the prevalence and US features of TGDC according to RIT. Methods: From July 2017 to June 2018, 3,146 subjects underwent thyroid or neck US at our center. The presence or absence of TGDCs was prospectively investigated based on real-time US examination. Among the 3,146 subjects, 261 subjects were excluded because of <18 years of age, unclear information of RIT, or the presence of a radiation therapy history to the neck. Eventually, 2,885 subjects were included in this study. Results: Of the 2,885 subjects finally included, 126 (4.4%) showed a TGDC on US. Those with RIT history showed a higher prevalence of TGDCs than those without (no statistical difference, p = 0.062). In 697 male subjects, there were statistical differences in type of surgery, RIT history, and session number of RIT between those with or without TGDCs (p < 0.0001). In 126 subjects with TGDCs, only sex showed a significant difference between those with or without RIT history (p = 0.015). However, there were no significant differences in the location, size, and shape of TGDCs (p > 0.05). The common US features of TGDC were suprahyoid location, ~1 centimeter, and flat-to-ovoid or round shape. Conclusions: RIT may increase the prevalence of TGDCs, particularly in men.

Asian Oceanian Radiology Forum 2018: International Education of Radiology in Asian Oceanian Countries.

According to the reports presented at the Fourth Asian Oceanian Radiology Forum (AORF) 2018, organized by the Korean Society of Radiology during the Korean Congress of Radiology in September 2018 in Seoul, there is an increasing demand for the Asian Oceanian Society of Radiology and its member societies for international education in radiology in the Asian Oceanian region. In AORF 2018, the national delegates of the Asian Oceanian radiological partner societies primarily discussed their societies' activities and current status of international education in radiology.

[Metallic Artifacts on MR Imaging and Methods for Their Reduction]. / MR 영상에서의 금속 인공물과 감소방법.

Metallic artifacts on MR imaging are typically induced by differences in magnetic susceptibility between the metallic implant and surrounding tissue. Conventional techniques for metal artifact reduction require MR machines with low field strength, shift in the frequency-encoding and phase-encoding directions according to the axis of metallic implant, increased receiver bandwidth and matrix, decreased slice thickness, and utilization of the short tau inversion recovery or Dixon method for fat-suppression. Slice-encoding for metal artifact correction and multi-acquisition variable-resonance image combination can dramatically reduce the number of metallic artifacts. However, these sequences have a considerably long acquisition time. Furthermore, the recently developed acceleration techniques including compressed sensing can solve this problem.

Comparison of Prevalence and Ultrasonography Features of Thyroglossal Duct Cyst in Adults According to Radioactive Iodine Ablation.

BACKGROUND This study aimed to evaluate the prevalence of thyroglossal duct cysts (TGDCs) on ultrasonography (US) and US features of TGDCs in adults, and to assess whether the prevalence or size of TGDCs increases after radioactive iodine ablation (RIA). MATERIAL AND METHODS Between July and December 2018, 2820 patients underwent thyroid or neck US examination, performed by 2 radiologists, at our center. On the basis of real-time US, the presence or absence of TGDCs was prospectively investigated by 2 radiologists. Among the 2820 patients, 54 patients who were <19 years of age or had a radiation therapy history to the neck were excluded. Eventually, 2766 patients were included. RESULTS Of the 2766 patients, 160 (5.8%) showed a TGDC on US. The mean size of TGDCs in RIA history (+) (n=36) and RIA history (-) (n=124) groups was 0.92±0.41 cm and 0.86±0.45 cm, respectively. There was no significant difference in size of TGDCs between RIA history (+) and RIA history (-) groups (p=0.684). Between the TGDC (+) and TGDC (-) groups, there was no significant difference in patient age, gender, reason for thyroid/neck US, type of thyroid surgery, and session number and application/no application of RIA (p>0.05). The prevalence rate of TGDCs in radiologist A and B was 4.9% (70/1427) and 6.7% (90/1339), respectively. TGDCs were more common in the suprahyoid neck, and the common shapes of TGDCs were flat-to-ovoid and round. CONCLUSIONS RIA may not be associated with the prevalence or enlargement of TGDCs.

Thyroid Imaging Reporting and Data System for Detecting Diffuse Thyroid Disease on Ultrasonography: A Single-Center Study.

Objective: This study aimed to compare the ultrasonography (US) features of diffuse thyroid disease (DTD) and normal thyroid parenchyma (NTP), and to propose a structured imaging reporting system for detecting DTD. Methods: This retrospective study assessed the findings for 270 consecutive patients who underwent thyroid US before thyroid surgery. The following US data were analyzed: DTD-specific features, parenchymal echotexture and echogenicity, anteroposterior diameter, glandular margin, and parenchymal vascularity. Univariate and multivariate analyses with generalized estimating equations were performed to investigate the relationship between US features and DTD. The fitted probability of DTD was analyzed by using a regression equation. Results: Of the 270 patients, there were NTP (n = 193), Hashimoto thyroiditis (n = 24), non-Hashimoto lymphocytic thyroiditis (n = 51), Graves' disease (n = 1), and diffuse hyperplasia (n = 1). The following US features were significantly associated with DTD: decreased or increased parenchymal echogenicity, coarse parenchymal echotexture, increased anteroposterior diameter, lobulated glandular margin, and increased parenchymal vascularity. Of these, coarse parenchymal echotexture was the most significant independent predictor of DTD. The numbers of abnormal US features were positively correlated with the fitted probability and risk of DTD. The diagnostic indices were highest when the chosen cut-off criterion was category III with the largest Az value (0.867, 95% confidence interval: 0.820-0.905), yielding a sensitivity of 68.8%, specificity of 92.2%, positive predictive value of 77.9%, negative predictive value of 88.1%, and accuracy of 85.6% (p < 0.001). Conclusions: Our sonographic reporting and data system may be useful for detecting DTD.

Unexpected Lung and Brain Metastases 9 Years After Thyroid Lobectomy for Follicular Adenoma: A Case Report.

Background: Benign thyroid follicular tumors without histological evidence of carcinoma can metastasize. However, the pathogenesis of metastasis remains unclear. Here, the new proposed terminology, "non-invasive follicular thyroid neoplasm with papillary-like nuclear features" should be considered. We present a case of an encapsulated type of follicular variant of papillary thyroid carcinoma (FVPTC) that exhibited distant lung and brain metastases and was initially diagnosed as follicular adenoma. Case Report: In December 2006, a 64-year-old woman underwent ultrasonography-guided fine-needle aspiration of the right thyroid nodule at our hospital because of a palpable right neck mass. Right lobectomy was performed, and a follicular adenoma was diagnosed. In October 2015, she visited our hospital owing to dry cough and mild dyspnea and underwent computed tomography-guided transthoracic core needle biopsy for the lung nodule owing to probably multiple lung metastasis on chest X-ray and computed tomography. Based on retrospective analysis of the primary thyroid tumor and lung nodule specimen, an encapsulated follicular variant of papillary thyroid carcinoma with lung metastasis was confirmed. Conclusion: We report a case of an encapsulated follicular variant of papillary thyroid carcinoma with unexpected metastasis to the lung 9 years after thyroid surgery in a patient who was initially diagnosed as follicular adenoma. A careful close follow-up with re-examination of the histopathology specimen may be needed in patients who were diagnosed with benign thyroid follicular tumors.

Utility of Preoperative Ultrasonography in Transferred Patients with Suspicious Malignancy on Ultrasonography-Guided Fine-Needle Aspiration Cytology of Thyroid Nodules: A Single-Center Retrospective Study.

BACKGROUND This study aimed to assess the utility and characteristics of preoperative ultrasonography (US) in patients transferred to referral hospitals from local clinics with a diagnosis of malignancy on US-guided fine-needle aspiration cytology of thyroid nodules. MATERIAL AND METHODS From January 2018 to June 2018, 109 transferred patients underwent preoperative US in our hospital for suspected thyroid malignancy on cytological analysis after US-guided fine-needle aspiration of thyroid nodules in local clinics. Preoperative US was performed by a single radiologist in all patients. Among them, 6 were excluded from the study because of refusal of thyroid surgery. Preoperative US and histopathological results were compared in all patients. RESULTS After thyroid surgery, pathological examination revealed papillary thyroid carcinoma (PTC) (n=98), follicular adenoma (n=1), and nodular hyperplasia (n=4). Of the 103 patients, 91 exhibited suspicious US findings on the preoperative US, whereas 12 did not. In the 91 patients with suspicious US findings, PTC (n=90) and follicular adenoma (n=1) were confirmed after thyroid surgery. In the 12 patients with no suspicious US findings, PTC (n=8) and nodular hyperplasia (n=4) were confirmed after thyroid surgery. On repeat analysis of the cytological slides of the 4 nodular hyperplasia cases from the local clinics, Bethesda category II (n=1) and III (n=3) were determined. CONCLUSIONS In the transferred patients with a malignant cytology, preoperative US might be helpful to detect false-positive cytology cases.

Ultrasound detection of incidental diffuse parotid disease: A single-center study.

In this study, we compared ultrasound (US) features between normal parotid parenchyma (NPP) and incidental diffuse parotid disease (DPD). From January 2008 to December 2017, 180 patients underwent neck US before parotid surgery at our hospital. From these, 82 were excluded because of the lack of histopathological data concerning the parotid parenchyma or inadequate US images. A single radiologist blinded to the clinicoserological data and histopathological results, retrospectively investigated all US features and categorizations for the parotid glands using a picture archiving and communication system. Retrospective histopathological analysis of the parotid parenchyma was performed by a single pathologist. On the basis of the histopathological analyses, the 98 patients were divided into NPP (n = 70) and DPD (n = 28) groups. Among US features, parenchymal echogenicity and echotexture showed statistically significant differences between the two groups (p < 0.0001), whereas the gland size, margin, and vascularity showed no significant differences (p > 0.05). The US-based categorization significantly differentiated between NPP and DPD (p < 0.0001), and receiver operating characteristic curve analysis revealed that US categorization based on ≥2 abnormal US features showed the best diagnostic performance for detecting DPD. Thus, US can aid in differentiating DPD from NPP.