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1.
Article | WPRIM | ID: wpr-835531

ABSTRACT

Background@#Differentiation of cerebellopontine angle (CPA) schwannoma from meningioma is often a difficult process to identify.Purpose: To identify imaging features for distinguishing CPA schwannoma from meningioma and to investigate the usefulness of susceptibility-weighted imaging (SWI) in differentiating them. @*Materials and Methods@#Between March 2010 and January 2015, this study pathologically confirmed 11 meningiomas and 20 schwannomas involving CPA with preoperative SWI were retrospectively reviewed. Generally, the following MRI features were evaluated: 1) maximal diameter on axial image, 2) angle between tumor border and adjacent petrous bone, 3) presence of intratumoral dark signal intensity on SWI, 4) tumor consistency, 5) blood-fluid level, 6) involvement of internal auditory canal (IAC), 7) dural tail, and 8) involvement of adjacent intracranial space. On CT, 1) presence of dilatation of IAC, 2) intratumoral calcification, and 3) adjacent hyperostosis were evaluated. All features were compared using Chi-squared tests and Fisher’s exact tests. The univariate and multivariate logistic regression analysis were performed to identify imaging features that differentiate both tumors. @*Results@#The results noted that schwannomas more frequently demonstrated dark spots on SWI (P = 0.025), cystic consistency (P = 0.034), and globular angle (P = 0.008); schwannomas showed more dilatation of internal auditory meatus and lack of calcification (P = 0.008 and P = 0.02, respectively). However, it was shown that dural tail was more common in meningiomas (P < 0.007). In general, dark spots on SWI and dural tail remained significant in multivariate analysis (P = 0.037 and P = 0.012, respectively). In this case, the combination of two features showed a sensitivity and specificity of 80% and 100% respectively, with an area under the receiver operating characteristic curve of 0.9. @*Conclusion@#In conclusion, dark spots on SWI were found to be helpful in differentiating CPA schwannoma from meningioma. It is noted that combining dural tail with dark spots on SWI yielded strong diagnostic value in differentiating both tumors.

2.
Korean Journal of Radiology ; : 1138-1145, 2019.
Article in English | WPRIM | ID: wpr-760287

ABSTRACT

OBJECTIVE: To compare apparent diffusion coefficients (ADCs) of brain segments by using two diffusion-weighted imaging acquisition modes, single-shot echo-planar imaging (ss-EPI) and read-out-segmented echo-planar imaging (rs-EPI), and to assess their correlation and agreement in healthy controls. MATERIALS AND METHODS: T2-weighted (T2W) images, rs-EPI, and ss-EPI of 30 healthy subjects were acquired using a 3T magnetic resonance scanner. The T2W images were co-registered to the rs-EPI and ss-EPI, which were then segmented into the gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) to generate masking templates. ADC maps of rs-EPI and ss-EPI were also segmented into the GM, WM, and CSF by using the generated templates. ADCs of rs-EPI and ss-EPI were compared using Student's t tests and correlated using Pearson's correlation coefficients. Bland-Altman plots were used to assess the agreement between acquisitions.


Subject(s)
Brain , Cerebrospinal Fluid , Diffusion , Echo-Planar Imaging , Gray Matter , Healthy Volunteers , Magnetic Resonance Imaging , Masks , White Matter
3.
Article in English | WPRIM | ID: wpr-719586

ABSTRACT

OBJECTIVE: For localization of the motor cortex, seed-based resting-state functional MRI (rsfMRI) uses the contralateral motor cortex as a seed. However, research has shown that the location of the motor cortex could differ according to anatomical variations. The purpose of this study was to compare the results of rsfMRI using two seeds: a template seed (the anatomically expected location of the contralateral motor cortex) and a functional seed (the actual location of the contralateral motor cortex determined by task-based functional MRI [tbfMRI]). MATERIALS AND METHODS: Eight patients (4 with glioma, 3 with meningioma, and 1 with arteriovenous malformation) and 9 healthy volunteers participated. For the patients, tbfMRI was performed unilaterally to activate the healthy contralateral motor cortex. The affected ipsilateral motor cortices were mapped with rsfMRI using seed-based and independent component analysis (ICA). In the healthy volunteer group, both motor cortices were mapped with both-hands tbfMRI and rsfMRI. We compared the results between template and functional seeds, and between the seed-based analysis and ICA with visual and quantitative analysis. RESULTS: For the visual analysis, the functional seed showed significantly higher scores compared to the template seed in both the patients (p = 0.002) and healthy volunteers (p < 0.001). Although no significant difference was observed between the functional seed and ICA, the ICA results showed significantly higher scores than the template seed in both the patients (p = 0.01) and healthy volunteers (p = 0.005). In the quantitative analysis, the functional seed exhibited greater similarity to tbfMRI than the template seed and ICA. CONCLUSION: Using the contralateral motor cortex determined by tbfMRI as a seed could enhance visual delineation of the motor cortex in seed-based rsfMRI.


Subject(s)
Brain Mapping , Brain Neoplasms , Glioma , Healthy Volunteers , Humans , Magnetic Resonance Imaging , Meningioma , Motor Cortex
4.
Article in English | WPRIM | ID: wpr-785720

ABSTRACT

BACKGROUND: To evaluate the imaging features, clinical manifestations, and prognosis of patients with thyroid nodule rupture after radiofrequency ablation (RFA).METHODS: The records of 12 patients who experienced thyroid nodule rupture after RFA at four Korean thyroid centers between March 2010 and July 2017 were retrospectively reviewed. Clinical data evaluated included baseline patient characteristics, treatment methods, initial presenting symptoms, imaging features, treatment, and prognosis.RESULTS: The most common symptoms of post-RFA nodule rupture were sudden neck bulging and pain. Based on imaging features, the localization of nodule rupture was classified into three types: anterior, posterolateral, and medial types. The anterior type is the most often, followed by posterolateral and medial type. Eight patients recovered completely after conservative treatment. Four patients who did not improve with conservative management required invasive procedures, including incision and drainage or aspiration.CONCLUSION: Thyroid nodule rupture after RFA can be classified into three types based on its localization: anterior, posterolateral, and medial types. Because majority of thyroid nodule ruptures after RFA can be managed conservatively, familiarity with these imaging features is essential in avoiding unnecessary imaging workup or invasive procedures.


Subject(s)
Catheter Ablation , Drainage , Humans , Neck , Prognosis , Recognition, Psychology , Retrospective Studies , Rupture , Thyroid Gland , Thyroid Nodule , Ultrasonography
5.
Article in English | WPRIM | ID: wpr-741439

ABSTRACT

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.


Subject(s)
Advisory Committees , Consensus , Ethanol , Expert Testimony , Thyroid Gland , Thyroid Neoplasms , Thyroid Nodule
6.
Article in English | WPRIM | ID: wpr-741434

ABSTRACT

OBJECTIVE: A developmental venous anomaly (DVA) is a vascular malformation of ambiguous clinical significance. We aimed to quantify the susceptibility of draining veins (χvein) in DVA and determine its significance with respect to oxygen metabolism using quantitative susceptibility mapping (QSM). MATERIALS AND METHODS: Brain magnetic resonance imaging of 27 consecutive patients with incidentally detected DVAs were retrospectively reviewed. Based on the presence of abnormal hyperintensity on T2-weighted images (T2WI) in the brain parenchyma adjacent to DVA, the patients were grouped into edema (E+, n = 9) and non-edema (E−, n = 18) groups. A 3T MR scanner was used to obtain fully flow-compensated gradient echo images for susceptibility-weighted imaging with source images used for QSM processing. The χvein was measured semi-automatically using QSM. The normalized χvein was also estimated. Clinical and MR measurements were compared between the E+ and E− groups using Student's t-test or Mann-Whitney U test. Correlations between the χvein and area of hyperintensity on T2WI and between χvein and diameter of the collecting veins were assessed. The correlation coefficient was also calculated using normalized veins. RESULTS: The DVAs of the E+ group had significantly higher χvein (196.5 ± 27.9 vs. 167.7 ± 33.6, p = 0.036) and larger diameter of the draining veins (p = 0.006), and patients were older (p = 0.006) than those in the E− group. The χvein was also linearly correlated with the hyperintense area on T2WI (r = 0.633, 95% confidence interval 0.333–0.817, p < 0.001). CONCLUSION: DVAs with abnormal hyperintensity on T2WI have higher susceptibility values for draining veins, indicating an increased oxygen extraction fraction that might be associated with venous congestion.


Subject(s)
Brain , Edema , Humans , Hyperemia , Magnetic Resonance Imaging , Metabolism , Oxygen , Retrospective Studies , Vascular Malformations , Veins
7.
Article in English | WPRIM | ID: wpr-716271

ABSTRACT

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.


Subject(s)
Advisory Committees , Catheter Ablation , Consensus , Humans , Thyroid Gland , Thyroid Neoplasms , Thyroid Nodule , Ultrasonography
8.
Article in English | WPRIM | ID: wpr-741371

ABSTRACT

OBJECTIVE: To assess the efficacy and safety of thyroid radiofrequency (RF) ablation for benign thyroid nodules by trained radiologists according to a unified protocol in a multi-center study. MATERIALS AND METHODS: From 2010 to 2011, 345 nodules from 345 patients (M:F = 43:302; mean age ± SD = 46.0 ± 12.7 years, range = 15–79) who met eligibility criteria were enrolled from five institutions. At pre-ablation, the mean volume was 14.2 ± 13.2 mL (1.1–80.8 mL). For 12 months or longer after treatment, 276 lesions, consisting of 248 solid and 28 predominantly cystic nodules, were followed. All operators performed RF ablation with a cool-tip RF system and two standard techniques (a transisthmic approach and the moving-shot technique). Volume reduction at 12 months after RF ablation (the primary outcome), therapeutic success, improvement of symptoms as well as of cosmetic problems, and complications were evaluated. Multiple linear regression analysis was applied to identify factors that were independently predictive of volume reduction. RESULTS: The mean volume reduction at 12 months was 80.3% (n = 276) and at the 24-, 36-, 48-, and 60-month follow-ups 84.3% (n = 198), 89.2% (n = 128), 91.9% (n = 57), and 95.3% (n = 6), respectively. Our therapeutic success was 97.8%. Both mean symptom and cosmetic scores showed significant improvements (p < 0.001). The rate of major complications was 1.0% (3/276). Solidity and applied energy were independent factors that predicted volume reduction. CONCLUSION: Radiofrequency ablation performed by trained radiologists from multiple institutions using a unified protocol and similar devices was effective and safe for treating benign thyroid nodules.


Subject(s)
Catheter Ablation , Follow-Up Studies , Humans , Linear Models , Prospective Studies , Thyroid Gland , Thyroid Nodule , Ultrasonography
9.
Article in English | WPRIM | ID: wpr-740145

ABSTRACT

PURPOSE: To assess associations between morphological characteristics of intracranial arteries in time-of-flight MR angiography (TOF-MRA) and atherosclerotic risk factors. MATERIALS AND METHODS: From January 2014 to October 2015, a total of 129 patients (65 men and 64 women) without intracranial arterial stenosis > 50% were included in this study. All MRIs were performed using a 3T machine with 3D TOF-MRA sequences. We evaluated irregularity, tortuosity, and dilatation of intracranial arteries in maximal intensity projection (MIP) of TOF-MRA. Subjects' risk factors for atherosclerosis including history of hypertension and diabetes were collected by reviewing their medical records. Associations between morphological characteristics and each known atherosclerosis risk factor were examined using univariate regression analysis. Multivariate regression models were built to determine combined association between those risk factors and morphologic changes of intracranial arteries. RESULTS: In multivariate analysis, hypertension (coefficient [95% CI]: 0.162 [0.036, 0.289], P = 0.012) and absence of diabetes (coefficient [95% CI]: −0.159 [−0.296, −0.023], P = 0.022) were associated with large diameter of intracranial arteries. Males (coefficient [95% CI]: 0.11 [−0.006, 0.23], P = 0.062) and higher age (coefficient [95% CI]: 0.003 [−0.001, 0.008], P = 0.138) had marginal association with increased diameter. Tortuosity was associated with old age (OR: 1.04 [1.02, 1.07], P < 0.001). Irregular contour of intracranial arteries was significantly associated with old age (OR: 1.05 [1.02, 1.09], P = 0.004), presence of diabetes (OR: 2.88 [1.36, 6.15], P = 0.0058), and previous ischemic stroke (OR: 3.91 [1.41, 11.16], P = 0.0092). CONCLUSION: Morphological characteristics (irregularity, tortuosity, dilatation) of intracranial arteries seen in TOF-MRA might be associated with atherosclerotic risk factors in subjects with no or mild stenosis.


Subject(s)
Angiography , Arteries , Atherosclerosis , Constriction, Pathologic , Dilatation , Humans , Hypertension , Magnetic Resonance Imaging , Male , Medical Records , Multivariate Analysis , Risk Factors , Stroke
10.
Article in English | WPRIM | ID: wpr-208823

ABSTRACT

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.


Subject(s)
Advisory Committees , Biopsy, Fine-Needle , Biopsy, Large-Core Needle , Consensus , Diagnosis , Humans , Methods , Thyroid Gland , Thyroid Neoplasms , Thyroid Nodule
11.
Article in English | WPRIM | ID: wpr-36759

ABSTRACT

OBJECTIVE: The purpose of this study was to compare the histogram analysis and visual scores in 3T MRI assessment of middle cerebral arterial wall enhancement in patients with acute stroke, for the differentiation of parent artery disease (PAD) from small artery disease (SAD). MATERIALS AND METHODS: Among the 82 consecutive patients in a tertiary hospital for one year, 25 patients with acute infarcts in middle cerebral artery (MCA) territory were included in this study including 15 patients with PAD and 10 patients with SAD. Three-dimensional contrast-enhanced T1-weighted turbo spin echo MR images with black-blood preparation at 3T were analyzed both qualitatively and quantitatively. The degree of MCA stenosis, and visual and histogram assessments on MCA wall enhancement were evaluated. A statistical analysis was performed to compare diagnostic accuracy between qualitative and quantitative metrics. RESULTS: The degree of stenosis, visual enhancement score, geometric mean (GM), and the 90th percentile (90P) value from the histogram analysis were significantly higher in PAD than in SAD (p = 0.006 for stenosis, < 0.001 for others). The receiver operating characteristic curve area of GM and 90P were 1 (95% confidence interval [CI], 0.86–1.00). CONCLUSION: A histogram analysis of a relevant arterial wall enhancement allows differentiation between PAD and SAD in patients with acute stroke within the MCA territory.


Subject(s)
Arteries , Constriction, Pathologic , Humans , Magnetic Resonance Imaging , Middle Cerebral Artery , Parents , ROC Curve , Stroke , Tertiary Care Centers
12.
Ultrasonography ; : 212-219, 2016.
Article in English | WPRIM | ID: wpr-731072

ABSTRACT

PURPOSE: This study was performed to determine the malignancy risk of thyroid nodules with isolated macrocalcification and to evaluate the diagnostic efficacy of fine-needle aspiration (FNA) and core needle biopsy (CNB). METHODS: From May 2008 to December 2014, a total of 44 patients with isolated macrocalcifications were enrolled from 4,081 consecutive patients who underwent FNA or CNB at a single institution. We assessed the malignancy risk of nodules with isolated macrocalcification. We compared the diagnostic results between FNA and CNB, and the diagnostic efficacy of each procedure was evaluated by the rate of inconclusive results. We compared the diagnostic performance for malignancy between FNA and CNB with a criterion of malignant or atypia/follicular lesion of undetermined significance (indeterminate) diagnostic results. We investigated whether the ultrasonographic feature of isolated macrocalcification was predictive of malignancy. RESULTS: The malignancy risk of nodules with isolated macrocalcification was 16.1% in 31 nodules with final diagnoses and 11.4% in all nodules. CNB demonstrated a significantly lower rate of nondiagnostic and inconclusive results than FNA (7.7% vs. 53.8%, P=0.002 and 15.4% vs. 57.7%, P=0.003, respectively) in 26 nodules that underwent both FNA and CNB. CNB showed a marginally higher diagnostic performance for identifying malignancy than FNA (P=0.067). The ultrasonographic features of the anterior margin of isolated macrocalcification were not predictive of malignancy (P>0.999). CONCLUSION: Thyroid nodules with isolated macrocalcification had a low to intermediate malignancy risk and should not be considered benign nodules. CNB showed a higher diagnostic efficacy than FNA in these nodules.


Subject(s)
Biopsy, Fine-Needle , Biopsy, Large-Core Needle , Diagnosis , Humans , Thyroid Gland , Thyroid Nodule , Ultrasonography
13.
Article in English | WPRIM | ID: wpr-82811

ABSTRACT

PURPOSE: To understand clinical significance of irregular interface between meningioma and adjacent brain parenchyma in predicting histological grading of tumor, focusing on brain parenchymal invasion. MATERIALS AND METHODS: Pathologically confirmed 79 cases with meningiomas with pathological reports about the presence of parenchymal invasion were included. We defined the presence of interface irregularity as either spiculations or fuzzy margins between the tumor and brain parenchyma. We counted number of spiculations and measured ratio of fuzzy margin length to whole length of mass with consensus of two neuroradiologists. We classified the patients into Present group and Absent group, and the two groups were compared by using the Mann-Whitney U test. Statistical correlations between the presence of an interface irregularity and brain parenchymal invasion by the tumor as well as meningioma histological grade were tested with chi-square test. The optimal cutoff values of spiculation numbers and the ratio of fuzzy margins were determined. The sensitivity and specificity of number of spiculations, ratio of fuzzy margin and the presence of irregular interface as combined parameters for predicting the parenchymal invasion were calculated using ROC curve analysis. RESULTS: Statistically significant differences were noted between the Present and Absent groups for number of spiculations and ratio of fuzzy margin (P = 0.038 and P = 0.028, respectively). The optimal cutoff value for number of spiculations (> 4.5 with 61.1% sensitivity and 68.9% specificity) and the ratio of fuzzy margin (> 0.24 with 66.7% sensitivity and 65.6% specificity) were determined. The sensitivity and specificity of interface irregularity as the combined parameters were 72% and 59%, respectively. The interface irregularity between tumor and brain parenchyma significantly correlated with not only brain parenchymal invasion (P = 0.001) and but also histological grade (P < 0.001). CONCLUSION: The interface irregularity between tumor and brain parenchyma in MRI can be a strong predictive factor for brain parenchymal invasion and high grade meningioma.


Subject(s)
Brain , Consensus , Humans , Magnetic Resonance Imaging , Meningioma , Pathology , ROC Curve , Sensitivity and Specificity
14.
Article in English | WPRIM | ID: wpr-106784

ABSTRACT

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.


Subject(s)
Ablation Techniques , Advisory Committees , Biopsy , Consensus , Diagnosis , Humans , Korea , Lymph Nodes , Multidetector Computed Tomography , Thyroid Gland , Thyroid Neoplasms , Thyroid Nodule , Ultrasonography
15.
Ultrasonography ; : 304-311, 2015.
Article in English | WPRIM | ID: wpr-731081

ABSTRACT

PURPOSE: The purpose of this study was to determine whether it is possible to differentiate benign from malignant thyroid nodules according to the proportion of sponge-like appearance within the nodules. METHODS: A total of 201 thyroid nodules containing sponge-like appearance from 195 patients (157 women and 38 men) were included this study. Each thyroid nodule was classified into one of three grades by real-time ultrasonography (US) based on the areas with a sponge-like appearance within nodule: grade I had sponge-like areas occupying 75%. We evaluated whether a correlation existed between these grades and cytopathologic diagnoses. RESULTS: Of the 201 nodules, 196 were benign and five were malignant, and according to the US classification, 101 nodules were grade I, 45 were grade II, and 55 were grade III. Of the five malignant nodules, four were grade I, and one was grade II. No statistically significant difference was found in the rate of malignancy between grade III and grades I and II, due to insufficient statistical power. A sponge-like appearance was correlated with follicles filled with colloid and cholesterol granules in benign nodules and with papillary fronds around the dilated cystic spaces in malignant nodules. CONCLUSION: No malignancies were found in thyroid nodules with >75% sponge-like appearance. Due to the overall low incidence of malignancy and the limited number of patients, a statistically significant difference could not be found in the prevalence of malignancy depending on the proportion of sponge-like areas within the nodule.


Subject(s)
Cholesterol , Classification , Colloids , Diagnosis , Diagnosis, Differential , Female , Humans , Incidence , Prevalence , Thyroid Gland , Thyroid Nodule , Ultrasonography
16.
Korean Journal of Radiology ; : 1353-1363, 2015.
Article in English | WPRIM | ID: wpr-172968

ABSTRACT

OBJECTIVE: To evaluate the image characteristics of subtraction magnetic resonance venography (SMRV) from time-resolved contrast-enhanced MR angiography (TRMRA) compared with phase-contrast MR venography (PCMRV) and single-phase contrast-enhanced MR venography (CEMRV). MATERIALS AND METHODS: Twenty-one patients who underwent brain MR venography (MRV) using standard protocols (PCMRV, CEMRV, and TRMRA) were included. SMRV was made by subtracting the arterial phase data from the venous phase data in TRMRA. Co-registration and subtraction of the two volume data was done using commercially available software. Image quality and the degree of arterial contamination of the three MRVs were compared. In the three MRVs, 19 pre-defined venous structures (14 dural sinuses and 5 cerebral veins) were evaluated. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the three MRVs were also compared. RESULTS: Single-phase contrast-enhanced MR venography showed better image quality (median score 4 in both reviewers) than did the other two MRVs (p < 0.001), whereas SMRV (median score 3 in both reviewers) and PCMRV (median score 3 in both reviewers) had similar image quality (p ≥ 0.951). SMRV (median score 0 in both reviewers) suppressed arterial signal better than did the other MRVs (median score 1 in CEMRV, median score 2 in PCMRV, both reviewers) (p < 0.001). The dural sinus score of SMRV (median and interquartile range [IQR] 48, 43-50 for reviewer 1, 47, 43-49 for reviewer 2) was significantly higher than for PCMRV (median and IQR 31, 25-34 for reviewer 1, 30, 23-32 for reviewer 2) (p < 0.01) and did not differ from that of CEMRV (median and IQR 50, 47-52 for reviewer 1, 49, 45-51 for reviewer 2) (p = 0.146 in reviewer 1 and 0.123 in reviewer 2). The SNR and CNR of SMRV (median and IQR 104.5, 83.1-121.2 and 104.1, 74.9-120.5, respectively) were between those of CEMRV (median and IQR 150.3, 111-182.6 and 148.4, 108-178.2) and PCMRV (median and IQR 59.4, 49.2-74.9 and 53.6, 43.8-69.2). CONCLUSION: Subtraction magnetic resonance venography is a promising MRV method, with acceptable image quality and good arterial suppression.


Subject(s)
Adult , Aged , Cerebral Veins/diagnostic imaging , Cranial Sinuses/diagnostic imaging , Female , Humans , Magnetic Resonance Angiography/instrumentation , Male , Middle Aged , Signal-To-Noise Ratio
17.
Article in English | WPRIM | ID: wpr-71456

ABSTRACT

PURPOSE: Susceptibility weighted imaging (SWI) is a new magnetic resonance technique that can exploit the magnetic susceptibility differences of various tissues. Intracranial hemorrhage (ICH) looks a dark blooming on the magnitude images of SWI. However, the pattern of ICH on phase images is not well known. The purpose of this study is to characterize hemorrhagic lesions on the phase images of SWI. MATERIALS AND METHODS: We retrospectively enrolled patients with ICH, who underwent both SWI and precontrast CT, between 2012 and 2013 (n = 95). An SWI was taken, using the 3-tesla system. A phase map was generated after post-processing. Cases with an intracranial hemorrhage were reviewed by an experienced neuroradiologist and a trainee radiologist, with 10 years and 3 years of experience, respectively. The types and stages of the hemorrhages were determined in correlation with the precontrast CT, the T1- and T2-weighted images, and the FLAIR images. The size of the hemorrhage was measured by a one-directional axis on a magnitude image of SWI. The phase values of the ICH were qualitatively evaluated: hypo-, iso-, and hyper-intensity. We summarized the imaging features of the intracranial hemorrhage on the phase map of the SWI. RESULTS: Four types of hemorrhage are observed: subdural and epidural; subarachnoid; parenchymal hemorrhage; and microbleed. The stages of the ICH were classified into 4 groups: acute (n = 34); early subacute (n = 11); late subacute (n = 15); chronic (n = 8); stage-unknown microbleeds (n = 27). The acute and early subacute hemorrhage showed heterogeneous mixed hyper-, iso-, and hypo-signal intensity; the late subacute hemorrhage showed homogeneous hyper-intensity, and the chronic hemorrhage showed a shrunken iso-signal intensity with the hyper-signal rim. All acute subarachnoid hemorrhages showed a homogeneous hyper-signal intensity. All parenchymal hemorrhages (> 3 mm) showed a dipole artifact on the phase images; however, microbleeds of less than 3 mm showed no dipole artifact. Larger hematomas showed a heterogeneous mixture of hyper-, iso-, and hypo-signal intensities. CONCLUSION: The pattern of the phase value of the SWI showed difference, according to the type, stage, and size.


Subject(s)
Artifacts , Axis, Cervical Vertebra , Hematoma , Hemorrhage , Humans , Intracranial Hemorrhages , Magnetic Resonance Imaging , Retrospective Studies , Subarachnoid Hemorrhage
18.
Article in English | WPRIM | ID: wpr-111042

ABSTRACT

Ultrasound (US)-guided fine needle aspiration (US-FNA) has played a crucial role in managing patients with thyroid nodules, owing to its safety and accuracy. However, even with US guidance, nondiagnostic sampling and infrequent complications still occur after FNA. Accordingly, the Task Force on US-FNA of the Korean Society of Thyroid Radiology has provided consensus recommendations for the US-FNA technique and related issues to improve diagnostic yield. These detailed procedures are based on a comprehensive analysis of the current literature and from the consensus of experts.


Subject(s)
Biopsy, Fine-Needle/methods , Consensus , Fibrinolytic Agents/adverse effects , Humans , Radiology , Sensitivity and Specificity , Thyroid Nodule/diagnosis
19.
Article in English | WPRIM | ID: wpr-111041

ABSTRACT

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.


Subject(s)
Adult , Aged , Diagnostic Imaging , Female , Humans , Male , Middle Aged , Neck/diagnostic imaging , Prospective Studies , Retrospective Studies , Sensitivity and Specificity , Thyroid Gland/pathology , Tomography, X-Ray Computed/methods , Young Adult
20.
Article in English | WPRIM | ID: wpr-228623

ABSTRACT

OBJECTIVE: To evaluate the efficacy of radiofrequency ablation (RFA) in the treatment of loco-regional, recurrent, and well-differentiated thyroid carcinoma. MATERIALS AND METHODS: Thirty-five recurrent well-differentiated thyroid carcinomas (RTC) in 32 patients were treated with RFA, between March 2008 and October 2011. RTCs were detected by regular follow-up ultrasound and confirmed by biopsy. All patients had fewer than 3 RTCs in the neck and were at high surgical risk or refused to undergo repeated surgery. Average number of RFA sessions were 1.3 (range 1-3). Post-RFA biopsy and ultrasound were performed. The mean follow-up period was 30 months. Pre- and post-RFA serum thyroglobulin values were evaluated. RESULTS: Thirty-one patients with 33 RTCs were treated with RFA only, whereas 1 patient with 2 RTCs was treated with RFA followed by surgery. At the last follow-up ultrasound, 31 (94%) of the 33 RTCs treated with RFA alone completely disappeared and the remaining 2 (6%) RTCs showed decreased volume. The largest diameter and volume of the 33 RTCs were markedly decreased by 93.2% (from 8.1 +/- 3.4 mm to 0.6 +/- 1.8 mm, p < 0.001) and 96.4% (from 173.9 +/- 198.7 mm3 to 6.2 +/- 27.9 mm3, p < 0.001), respectively. Twenty of the 21 RTCs evaluated with post-RFA biopsies (95%) were negative for malignancy. One (5%) showed remaining tumor that was removed surgically. The serum thyroglobulin was decreased in 19 of 26 patients (73%). Voice change developed immediately after RFA in 6 patients (19%) and was spontaneously recovered in 5 patients (83%). CONCLUSION: Radiofrequency ablation can be effective in treating loco-regional, recurrent, and well-differentiated thyroid carcinoma in patients at high surgical risk.


Subject(s)
Adult , Aged , Aged, 80 and over , Carcinoma/pathology , Catheter Ablation , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Recurrence, Local , Neoplasm Staging , Thyroglobulin/blood , Thyroid Neoplasms/pathology , Tomography, X-Ray Computed
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