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1.  Measurement of Opening and Closing Angles of Aortic Valve Prostheses In Vivo Using Dual-Source Computed Tomography: Comparison with Those of Manufacturers' in 10 Different Types 
Korean Journal of Radiology  2015;16(5):1012-1023.
The aims of this study were to compare opening and closing angles of normally functioning mechanical aortic valves measured on dual-source computed tomography (CT) with the manufacturers' values and to compare CT-measured opening angles according to valve function.
Materials and Methods
A total of 140 patients with 10 different types of mechanical aortic valves, who underwent dual-source cardiac CT, were included. Opening and closing angles were measured on CT images. Agreement between angles in normally functioning valves and the manufacturer values was assessed using the interclass coefficient and the Bland-Altman method. CT-measured opening angles were compared between normal functioning valves and suspected dysfunctioning valves.
The CT-measured opening angles of normally functioning valves and manufacturers' values showed excellent agreement for seven valve types (intraclass coefficient [ICC], 0.977; 95% confidence interval [CI], 0.962-0.987). The mean differences in opening angles between the CT measurements and the manufacturers' values were 1.2° in seven types of valves, 11.0° in On-X valves, and 15.5° in ATS valves. The manufacturers' closing angles and those measured by CT showed excellent agreement for all valve types (ICC, 0.953; 95% CI, 0.920-0.972). Among valves with suspected dysfunction, those with limitation of motion (LOM) and an increased pressure gradient (PG) had smaller opening angles than those with LOM only (p < 0.05).
Dual-source cardiac CT accurately measures opening and closing angles in most types of mechanical aortic valves, compared with the manufacturers' values. Opening angles on CT differ according to the type of valve dysfunction and a decreased opening angle may suggest an elevated PG.
PMCID: PMC4559772  PMID: 26356549
Mechanical aortic valve; Opening and closing angles; Measurement; Dual-source computed tomography
2.  Myocardial Contrast Defect Associated with Thrombotic Coronary Occlusion: Pre-Autopsy Diagnosis of a Cardiac Death with Post-Mortem CT Angiography 
Korean Journal of Radiology  2015;16(5):1024-1028.
We report the case of a female who died of suspected acute myocardial infarction. Post-mortem CT angiography (PMCTA) was performed with intravascular contrast infusion before the standard autopsy, and it successfully demonstrated the complete thrombotic occlusion of a coronary artery and also a corresponding perfusion defect on myocardium. We herein describe the PMCTA findings of a cardiac death with special emphasis on the potential benefits of this novel CT technique in forensic practice.
PMCID: PMC4559773  PMID: 26357496
Post-mortem radiology; CT angiography; Coronary thrombosis; Myocardial perfusion
3.  Dynamic Contrast-Enhanced MRI Using a Macromolecular MR Contrast Agent (P792): Evaluation of Antivascular Drug Effect in a Rabbit VX2 Liver Tumor Model 
Korean Journal of Radiology  2015;16(5):1029-1037.
To evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using macromolecular contrast agent (P792) for assessment of vascular disrupting drug effect in rabbit VX2 liver tumor models.
Materials and Methods
This study was approved by our Institutional Animal Care and Use Committee. DCE-MRI was performed with 3-T scanner in 13 VX2 liver tumor-bearing rabbits, before, 4 hours after, and 24 hours after administration of vascular disrupting agent (VDA), using gadomelitol (P792, n = 7) or low molecular weight contrast agent (gadoterate meglumine [Gd-DOTA], n = 6). P792 was injected at a of dose 0.05 mmol/kg, while that of Gd-DOTA was 0.2 mmol/kg. DCE-MRI parameters including volume transfer coefficient (Ktrans) and initial area under the gadolinium concentration-time curve until 60 seconds (iAUC) of tumors were compared between the 2 groups at each time point. DCE-MRI parameters were correlated with tumor histopathology. Reproducibility in measurement of DCE-MRI parameters and image quality of source MR were compared between groups.
P792 group showed a more prominent decrease in Ktrans and iAUC at 4 hours and 24 hours, as compared to the Gd-DOTA group. Changes in DCE-MRI parameters showed a weak correlation with histologic parameters (necrotic fraction and microvessel density) in both groups. Reproducibility of DCE-MRI parameters and overall image quality was not significantly better in the P792 group, as compared to the Gd-DOTA group.
Dynamic contrast-enhanced magnetic resonance imaging using a macromolecular contrast agent shows changes of hepatic perfusion more clearly after administration of the VDA. Gadolinium was required at smaller doses than a low molecular contrast agent.
PMCID: PMC4559774  PMID: 26357497
Magnetic resonance imaging; Contrast agents; Antitumor agents; Animal experimentation; Liver neoplasms
4.  T2-Weighted Liver MRI Using the MultiVane Technique at 3T: Comparison with Conventional T2-Weighted MRI 
Korean Journal of Radiology  2015;16(5):1038-1046.
To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions.
Materials and Methods
Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis.
MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001).
Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.
PMCID: PMC4559775  PMID: 26357498
Magnetic resonance imaging; 3T MRI; MultiVane; T2-weighted imaging
5.  Feasibility Study of Radiation Dose Reduction in Adult Female Pelvic CT Scan with Low Tube-Voltage and Adaptive Statistical Iterative Reconstruction 
Korean Journal of Radiology  2015;16(5):1047-1055.
To evaluate image quality of female pelvic computed tomography (CT) scans reconstructed with the adaptive statistical iterative reconstruction (ASIR) technique combined with low tube-voltage and to explore the feasibility of its clinical application.
Materials and Methods
Ninety-four patients were divided into two groups. The study group used 100 kVp, and images were reconstructed with 30%, 50%, 70%, and 90% ASIR. The control group used 120 kVp, and images were reconstructed with 30% ASIR. The noise index was 15 for the study group and 11 for the control group. The CT values and noise levels of different tissues were measured. The contrast to noise ratio (CNR) was calculated. A subjective evaluation was carried out by two experienced radiologists. The CT dose index volume (CTDIvol) was recorded.
A 44.7% reduction in CTDIvol was observed in the study group (8.18 ± 3.58 mGy) compared with that in the control group (14.78 ± 6.15 mGy). No significant differences were observed in the tissue noise levels and CNR values between the 70% ASIR group and the control group (p = 0.068-1.000). The subjective scores indicated that visibility of small structures, diagnostic confidence, and the overall image quality score in the 70% ASIR group was the best, and were similar to those in the control group (1.87 vs. 1.79, 1.26 vs. 1.28, and 4.53 vs. 4.57; p = 0.122-0.585). No significant difference in diagnostic accuracy was detected between the study group and the control group (42/47 vs. 43/47, p = 1.000).
Low tube-voltage combined with automatic tube current modulation and 70% ASIR allowed the low CT radiation dose to be reduced by 44.7% without losing image quality on female pelvic scan.
PMCID: PMC4559776  PMID: 26357499
Adaptive statistical iterative reconstruction; Tube-voltage; CT; Radiation dose
6.  Immunoglobulin G4-Related Kidney Disease: A Comprehensive Pictorial Review of the Imaging Spectrum, Mimickers, and Clinicopathological Characteristics 
Korean Journal of Radiology  2015;16(5):1056-1067.
Immunoglobulin G4 (IgG4)-related kidney disease (IgG4-KD) has recently been demonstrated to be an important part of IgG4-related sclerosing disease (IgG4-SD). However, since IgG4-KD is still relatively unfamiliar to radiologists and physicians as compared to IgG4-SD involving other organs, it could, therefore, be easily missed. In this article, we present a comprehensive pictorial review of IgG4-KD with regards to the imaging spectrum, mimickers, and clinicopathologic characteristics, based on our clinical experience with 48 patients during the past 13 years, as well as a literature review. Awareness of the broad imaging spectrum of IgG4-KD and differential diagnosis from its mimickers will thus facilitate its early diagnosis and treatment.
PMCID: PMC4559777  PMID: 26357500
Immunoglobulin G4-related kidney disease; Immunoglobulin G4-related sclerosing disease; CT; MR Imaging
7.  Does Establishing a Safety Margin Reduce Local Recurrence in Subsegmental Transarterial Chemoembolization for Small Nodular Hepatocellular Carcinomas? 
Korean Journal of Radiology  2015;16(5):1068-1078.
To test the hypothesis that a safety margin may affect local tumor recurrence (LTR) in subsegmental chemoembolization.
Materials and Methods
In 101 patients with 128 hepatocellular carcinoma (HCC) nodules (1-3 cm in size and ≤ 3 in number), cone-beam CT-assisted subsegmental lipiodol chemoembolization was performed. Immediately thereafter, a non-contrast thin-section CT image was obtained to evaluate the presence or absence of intra-tumoral lipiodol uptake defect and safety margin. The effect of lipiodol uptake defect and safety margin on LTR was evaluated. Univariate and multivariate analyses were performed to indentify determinant factors of LTR.
Of the 128 HCC nodules in 101 patients, 49 (38.3%) nodules in 40 patients showed LTR during follow-up period (median, 34.1 months). Cumulative 1- and 2-year LTR rates of nodules with lipiodol uptake defect (n = 27) and those without defect (n = 101) were 58.1% vs. 10.1% and 72.1% vs. 19.5%, respectively (p < 0.001). Among the 101 nodules without a defect, the 1- and 2-year cumulative LTR rates for nodules with complete safety margin (n = 52) and those with incomplete safety margin (n = 49) were 9.8% vs. 12.8% and 18.9% vs. 19.0% (p = 0.912). In multivariate analyses, ascites (p = 0.035), indistinct tumor margin on cone-beam CT (p = 0.039), heterogeneous lipiodol uptake (p = 0.023), and intra-tumoral lipiodol uptake defect (p < 0.001) were determinant factors of higher LTR.
In lipiodol chemoembolization, the safety margin in completely lipiodolized nodule without defect will not affect LTR in small nodular HCCs.
PMCID: PMC4559778  PMID: 26357501
Safety margin; Local tumor recurrence; Subsegmental transarterial chemoembolization; Hepatocellular carcinoma; Cone-beam CT
8.  Complications of Portal Vein Embolization: Evaluation on Cross-Sectional Imaging 
Korean Journal of Radiology  2015;16(5):1079-1085.
Portal vein embolization (PVE) is known as an effective and safe preoperative procedure that increases the future liver remnant (FLR) in patients with insufficient FLR. However, some possible major complications can lead to non-resectability or delayed elective surgery that results in increased morbidity and mortality. Although the majority of these complications are rare, knowledge of the radiologic findings of post-procedural complications facilitate an accurate diagnosis and ensure prompt management. We accordingly reviewed the CT findings of the complications of PVE.
PMCID: PMC4559779  PMID: 26357502
Portal vein embolization; Complication; CT
9.  Comparison of Multi-Echo Dixon Methods with Volume Interpolated Breath-Hold Gradient Echo Magnetic Resonance Imaging in Fat-Signal Fraction Quantification of Paravertebral Muscle 
Korean Journal of Radiology  2015;16(5):1086-1095.
To assess whether multi-echo Dixon magnetic resonance (MR) imaging with simultaneous T2* estimation and correction yields more accurate fat-signal fraction (FF) measurement of the lumbar paravertebral muscles, in comparison with non-T2*-corrected two-echo Dixon or T2*-corrected three-echo Dixon, using the FF measurements from single-voxel MR spectroscopy as the reference standard.
Materials and Methods
Sixty patients with low back pain underwent MR imaging with a 1.5T scanner. FF mapping images automatically obtained using T2*-corrected Dixon technique with two (non-T2*-corrected), three, and six echoes, were compared with images from single-voxel MR spectroscopy at the paravertebral muscles on levels L4 through L5. FFs were measured directly by two radiologists, who independently drew the region of interest on the mapping images from the three sequences.
A total of 117 spectroscopic measurements were performed either bilaterally (57 of 60 subjects) or unilaterally (3 of 60 subjects). The mean spectroscopic FF was 14.3 ± 11.7% (range, 1.9-63.7%). Interobserver agreement was excellent between the two radiologists. Lin's concordance correlation between the spectroscopic findings and all the imaging-based FFs were statistically significant (p < 0.001). FFs obtained from the T2*-corrected six-echo Dixon sequences showed a significantly better concordance with the spectroscopic data, with its concordance correlation coefficient being 0.99 and 0.98 (p < 0.001), as compared with two- or three-echo methods.
T2*-corrected six-echo Dixon sequence would be a better option than two- or three-echo methods for noninvasive quantification of lumbar muscle fat quantification.
PMCID: PMC4559780  PMID: 26357503
Magnetic resonance imaging; Fat-signal fraction; Dixon; Muscle; Spine
10.  Deltoid Ligament and Tibiofibular Syndesmosis Injury in Chronic Lateral Ankle Instability: Magnetic Resonance Imaging Evaluation at 3T and Comparison with Arthroscopy 
Korean Journal of Radiology  2015;16(5):1096-1103.
To evaluate the prevalence of deltoid ligament and distal tibiofibular syndesmosis injury on 3T magnetic resonance imaging (MRI) in patients with chronic lateral ankle instability (CLAI).
Materials and Methods
Fifty patients (mean age, 35 years) who had undergone preoperative 3T MRI and surgical treatment for CLAI were enrolled. The prevalence of deltoid ligament and syndesmosis injury were assessed. The complexity of lateral collateral ligament complex (LCLC) injury was correlated with prevalence of deltoid or syndesmosis injuries. The diagnostic accuracy of ankle ligament imaging at 3T MRI was analyzed using arthroscopy as a reference standard.
On MRI, deltoid ligament injury was identified in 18 (36%) patients as follows: superficial ligament alone, 9 (50%); deep ligament alone 2 (11%); and both ligaments 7 (39%). Syndesmosis abnormality was found in 21 (42%) patients as follows: anterior inferior tibiofibular ligament (AITFL) alone, 19 (90%); and AITFL and interosseous ligament, 2 (10%). There was no correlation between LCLC injury complexity and the prevalence of an accompanying deltoid or syndesmosis injury on both MRI and arthroscopic findings. MRI sensitivity and specificity for detection of deltoid ligament injury were 84% and 93.5%, and those for detection of syndesmosis injury were 91% and 100%, respectively.
Deltoid ligament or syndesmosis injuries were common in patients undergoing surgery for CLAI, regardless of the LCLC injury complexity. 3T MRI is helpful for the detection of all types of ankle ligament injury. Therefore, careful interpretation of pre-operative MRI is essential.
PMCID: PMC4559781  PMID: 26356649
Chronic ankle instability; Lateral collateral ligament; Deltoid ligament; Syndesmosis; Magnetic resonance imaging; 3T
11.  Atypical Unilateral Posterior Reversible Encephalopathy Syndrome Mimicking a Middle Cerebral Artery Infarction 
Korean Journal of Radiology  2015;16(5):1104-1108.
Posterior reversible encephalopathy syndrome (PRES) is usually a reversible clinical and radiological entity associated with typical features on brain MR or CT imaging. However, the not-so-uncommon atypical radiological presentations of the condition are also present and they may go unrecognised as they are confused with other conditions. Here, we report a very rare case of atypical, unilateral PRES in a 49-year-old uremic, post-transplant female patient who presented with seizures. Initial MRI showed high-grade occlusion of the left middle cerebral artery (MCA) and lesions suggestive of subacute infarction in the ipsilateral frontotemporoparietal lobe. Patient symptoms had resolved a day after the onset without any specific treatment but early follow-up CT findings suggested hemorrhagic transformation. Follow-up MRI performed 2 years later showed complete disappearence of the lesions and persisting MCA occlusion.
PMCID: PMC4559782  PMID: 26356795
Posterior reversible encephalopathy syndrome; Atypical; Unilateral; Infarction
12.  Use of Triple Microcatheters for Endovascular Treatment of Wide-Necked Intracranial Aneurysms: A Single Center Experience 
Korean Journal of Radiology  2015;16(5):1109-1118.
The dual microcatheter technique is common practice for coil embolization of a wide-necked aneurysm, due to safety and efficacy. However, technical limitations of some complex configurations may necessitate additional microcatheters to bolster coil stability, compact the coil, or for protection. Described herein is a triple microcatheter technique for endovascular management of wide-necked intracranial aneurysms.
Materials and Methods
Data accruing prospectively between January 2006 and October 2014 on simultaneously executed triple microcatheter coil embolization procedures done in 38 saccular aneurysms were reviewed. Clinical and morphological outcomes were assessed, with emphasis on technical aspects of treatment.
The triple microcatheter technique was successfully applied to all 38 saccular aneurysms, involving the posterior communicating artery (n = 13), the middle cerebral artery (n = 10), the basilar tip (n = 7), the anterior cerebral artery (n = 5), and the internal carotid artery (n = 3). Stent protection was added in four patients and balloon remodeling in one. Dual microcatheters (n = 24) were usually deployed to deliver the coil within sacs of aneurysms, with the additional microcatheter used for protection. Otherwise, triple microcatheters were deployed for coil delivery (n = 11) or coils were delivered via a single microcatheter, with dual microcatheters deployed for protection (n = 3). Successful occlusion of aneurysms was achieved in 89.5% of cases, with no procedure-related morbidity or mortality. Stable occlusion was maintained in 72.2% (26/36) of the aneurysms at the final follow-up (mean interval, 30.2 ± 22.7 months).
The outcomes of this limited study suggest that the triple microcatheter technique may be an effective and safe therapeutic option for wide-necked aneurysms, using technical strategies tailored to complex angio-anatomic configurations.
PMCID: PMC4559783  PMID: 26356992
Aneurysm; Coil; Embolization; Protective; Technique
13.  Spinal Dural Arteriovenous Fistula: Imaging Features and Its Mimics 
Korean Journal of Radiology  2015;16(5):1119-1131.
Spinal dural arteriovenous fistula (SDAVF) is the most common spinal vascular malformation, however it is still rare and underdiagnosed. Magnetic resonance imaging findings such as spinal cord edema and dilated and tortuous perimedullary veins play a pivotal role in the confirmation of the diagnosis. However, spinal angiography remains the gold standard in the diagnosis of SDAVF. Classic angiographic findings of SDAVF are early filling of radicular veins, delayed venous return, and an extensive network of dilated perimedullary venous plexus. A series of angiograms of SDAVF at different locations along the spinal column, and mimics of serpentine perimedullary venous plexus on MR images, are demonstrated. Thorough knowledge of SDAVF aids correct diagnosis and prevents irreversible complications.
PMCID: PMC4559784  PMID: 26357504
Central nervous system vascular malformations; Spinal cord diseases; Spine
14.  Adaptive Statistical Iterative Reconstruction-Applied Ultra-Low-Dose CT with Radiography-Comparable Radiation Dose: Usefulness for Lung Nodule Detection 
Korean Journal of Radiology  2015;16(5):1132-1141.
To assess the performance of adaptive statistical iterative reconstruction (ASIR)-applied ultra-low-dose CT (ULDCT) in detecting small lung nodules.
Materials and Methods
Thirty patients underwent both ULDCT and standard dose CT (SCT). After determining the reference standard nodules, five observers, blinded to the reference standard reading results, independently evaluated SCT and both subsets of ASIR- and filtered back projection (FBP)-driven ULDCT images. Data assessed by observers were compared statistically.
Converted effective doses in SCT and ULDCT were 2.81 ± 0.92 and 0.17 ± 0.02 mSv, respectively. A total of 114 lung nodules were detected on SCT as a standard reference. There was no statistically significant difference in sensitivity between ASIR-driven ULDCT and SCT for three out of the five observers (p = 0.678, 0.735, < 0.01, 0.038, and < 0.868 for observers 1, 2, 3, 4, and 5, respectively). The sensitivity of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT in three out of the five observers (p < 0.01 for three observers, and p = 0.064 and 0.146 for two observers). In jackknife alternative free-response receiver operating characteristic analysis, the mean values of figure-of-merit (FOM) for FBP, ASIR-driven ULDCT, and SCT were 0.682, 0.772, and 0.821, respectively, and there were no significant differences in FOM values between ASIR-driven ULDCT and SCT (p = 0.11), but the FOM value of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT and SCT (p = 0.01 and 0.00).
Adaptive statistical iterative reconstruction-driven ULDCT delivering a radiation dose of only 0.17 mSv offers acceptable sensitivity in nodule detection compared with SCT and has better performance than FBP-driven ULDCT.
PMCID: PMC4559785  PMID: 26357505
Multidetector computed tomography; Image reconstruction; Adaptive statistical iterative reconstruction; Lung; Radiation dosage
15.  CT Characteristics of Pleural Plaques Related to Occupational or Environmental Asbestos Exposure from South Korean Asbestos Mines 
Korean Journal of Radiology  2015;16(5):1142-1152.
This study evaluated the CT characteristics of pleural plaques in asbestos-exposed individuals and compared occupational versus environmental exposure groups.
Materials and Methods
This study enrolled 181 subjects with occupational exposure and 98 with environmental exposure from chrysotile asbestos mines, who had pleural plaques confirmed by a chest CT. The CT scans were analyzed for morphological characteristics, the number and distribution of pleural plaques and combined pulmonary fibrosis. Furthermore, the CT findings were compared between the occupational and environmental exposure groups.
Concerning the 279 subjects, the pleural plaques were single in 2.2% and unilateral in 3.6%, and showed variable widths (range, 1-20 mm; mean, 5.4 ± 2.7 mm) and lengths (5-310 mm; 72.6 ± 54.8 mm). The chest wall was the most commonly involved (98.6%), with an upper predominance on the ventral side (upper, 77.8% vs. lower, 55.9%, p < 0.001) and a lower predominance on the dorsal side (upper, 74.9% vs. lower, 91.8%, p = 0.02). Diaphragmatic involvement (78.1%) showed a right-side predominance (right, 73.8% vs. left, 55.6%, p < 0.001), whereas mediastinal plaques (42.7%) were more frequent on the left (right, 17.6% vs. left, 39.4%, p < 0.001). The extent and maximum length of plaques, and presence and severity of combined asbestosis, were significantly higher in the occupational exposure group (p < 0.05).
Pleural plaques in asbestos-exposed individuals are variable in number and size; and show a predominant distribution in the upper ventral and lower dorsal chest walls, right diaphragm, and left mediastinum. Asbestos mine workers have a higher extent of plaques and pulmonary fibrosis versus environmentally exposed individuals.
PMCID: PMC4559786  PMID: 26357506
Pleural plaques; Asbestos; Computed tomography; Occupational diseases
16.  A Pleural Loose Body Mimicking a Pleural Tumor: A Case Report 
Korean Journal of Radiology  2015;16(5):1163-1165.
We present a rare case of a pleural loose body, thought to be a pedunculated pleural tumor, found incidentally in a 58-year-old female. Computed tomography showed a non-enhancing mass, which migrated along the mediastinum and paravertebral area. Thoracoscopic surgery revealed a 4 cm, soap-like mass that was found to be a fibrin body consisting of hyalinized collagen histopathologically. Mobility and the lack of contrast enhancement of a pleural mass are important clues to diagnosing this benign condition.
PMCID: PMC4559788  PMID: 26355378
Thoracolithiasis; Loose body; Pleural cavity; Computed tomography
17.  Primary Pulmonary Low-Grade Angiosarcoma Characterized by Mismatch between 18F-FDG PET and Dynamic Contrast-Enhanced CT 
Korean Journal of Radiology  2015;16(5):1166-1170.
We report a rare case of primary pulmonary low-grade angiosarcoma on dynamic contrast-enhanced CT and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging. A 38-year-old, asymptomatic woman was hospitalized because of an abnormality on chest radiography. A dynamic contrast-enhanced chest CT showed a 1.2 cm-sized irregular-margined nodule with strong and persistent enhancement in the right lower lobe. The lesion had low metabolic activity on an 18F-FDG PET/CT scan. The patient underwent a wedge resection for the lesion, and pathology revealed a primary pulmonary low-grade angiosarcoma.
PMCID: PMC4559789  PMID: 26357507
Primary pulmonary angiosarcoma; Low-grade; 18F-FDG PET/CT; Dynamic contrast-enhanced CT
18.  RE: Efficacy of Cervical Interlaminar Epidural Steroid Injections 
Korean Journal of Radiology  2015;16(5):1171-1172.
PMCID: PMC4559790  PMID: 26357508
Cervical; Epidural; Radiculopathy
19.  Nuclear Molecular Imaging for Vulnerable Atherosclerotic Plaques 
Korean Journal of Radiology  2015;16(5):955-966.
Atherosclerosis is an inflammatory disease as well as a lipid disorder. Atherosclerotic plaque formed in vessel walls may cause ischemia, and the rupture of vulnerable plaque may result in fatal events, like myocardial infarction or stroke. Because morphological imaging has limitations in diagnosing vulnerable plaque, molecular imaging has been developed, in particular, the use of nuclear imaging probes. Molecular imaging targets various aspects of vulnerable plaque, such as inflammatory cell accumulation, endothelial activation, proteolysis, neoangiogenesis, hypoxia, apoptosis, and calcification. Many preclinical and clinical studies have been conducted with various imaging probes and some of them have exhibited promising results. Despite some limitations in imaging technology, molecular imaging is expected to be used both in the research and clinical fields as imaging instruments become more advanced.
PMCID: PMC4559792  PMID: 26357491
Vulnerable plaque; PET; SPECT; Molecular imaging
20.  Differences in Regional Glucose Metabolism of the Brain Measured with F-18-FDG-PET in Patients with Essential Tremor According to Their Response to Beta-Blockers 
Korean Journal of Radiology  2015;16(5):967-972.
In this study, there was an investigation as to whether there is a functional difference in essential tremor (ET), according to responses to beta-blockers, by evaluating regional changes in cerebral glucose metabolism.
Materials and Methods
Seventeen male patients with ET were recruited and categorized into two groups: 8 that responded to medical therapy (group A); and 9 that did not respond to medical therapy (group B). Eleven age-sex matched healthy control male subjects were also included in this study. All subjects underwent F-18 fluorodeoxyglucose (FDG)-PET, and evaluated for their severity of tremor symptoms, which were measured as a score on the Fahn-Tolosa-Marin tremor rating scale (FTM). The FDG-PET images were analyzed using a statistical parametric mapping program.
The mean FTM score 6 months after the initiation of propranolol therapy was significantly lower in group A (18.13 > 8.13), compared with group B (14.67 = 14.67). The glucose metabolism in group A in the left basal ganglia was seen to be decreased, compared with group B. The ET showed a more significantly decreased glucose metabolism in both the fronto-temporo-occipital lobes, precuneus of right parietal lobe, and both cerebellums compared with the healthy controls.
Essential tremor is caused by electrophysiological disturbances within the cortical-cerebellar networks and degenerative process of the cerebellum. Furthermore, ET may have different pathophysiologies in terms of the origin of disease according to the response to first-line therapy.
PMCID: PMC4559793  PMID: 26357492
Essential tremor; Beta-blockers; FDG-PET
21.  Whole-Body MRI in Children: Current Imaging Techniques and Clinical Applications 
Korean Journal of Radiology  2015;16(5):973-985.
Whole-body magnetic resonance imaging (MRI) is increasingly used in children to evaluate the extent and distribution of various neoplastic and non-neoplastic diseases. Not using ionizing radiation is a major advantage of pediatric whole-body MRI. Coronal and sagittal short tau inversion recovery imaging is most commonly used as the fundamental whole-body MRI protocol. Diffusion-weighted imaging and Dixon-based imaging, which has been recently incorporated into whole-body MRI, are promising pulse sequences, particularly for pediatric oncology. Other pulse sequences may be added to increase diagnostic capability of whole-body MRI. Of importance, the overall whole-body MRI examination time should be less than 30-60 minutes in children, regardless of the imaging protocol. Established and potentially useful clinical applications of pediatric whole-body MRI are described.
PMCID: PMC4559794  PMID: 26355493
Whole-body MRI; Infants and children; Tumor; Systemic disease
22.  Prognostic Significance of a Complete Response on Breast MRI in Patients Who Received Neoadjuvant Chemotherapy According to the Molecular Subtype 
Korean Journal of Radiology  2015;16(5):986-995.
To evaluate the relationship between response categories assessed by magnetic resonance imaging (MRI) or pathology and survival outcomes, and to determine whether there are prognostic differences among molecular subtypes.
Materials and Methods
We evaluated 174 patients with biopsy-confirmed invasive breast cancer who had undergone MRI before and after neoadjuvant chemotherapy, but before surgery. Pathology findings were classified as a pathologic complete response (pCR) or a non-pCR, and MRI findings were designated as a radiologic CR (rCR) or a non-rCR. We evaluated overall and subtype-specific associations between clinicopathological factors including the assessment categories and recurrence, using the Cox proportional hazards model.
There were 41 recurrences (9 locoregional and 32 distant recurrences). There were statistically significant differences in recurrence outcomes between patients who achieved a radiologic or a pCR and patients who did not achieve a radiologic or a pCR (recurrence hazard ratio, 11.02; p = 0.018 and recurrence hazard ratio, 3.93; p = 0.022, respectively). Kaplan-Meier curves for recurrence-free survival showed that triple-negative breast cancer was the only subtype that showed significantly better outcomes in patients who achieved a CR compared to patients who did not achieve a CR by both radiologic and pathologic assessments (p = 0.004 and 0.001, respectively). A multivariate analysis found that patients who achieved a rCR and a pCR did not display significantly different recurrence outcomes (recurrence hazard ratio, 2.02; p = 0.505 and recurrence hazard ratio, 1.12; p = 0.869, respectively).
Outcomes of patients who achieved a rCR were similar to those of patients who achieved a pCR. To evaluate survival difference according to molecular subtypes, a larger study is needed.
PMCID: PMC4559795  PMID: 26357493
Breast cancer; Magnetic resonance imaging; Neoadjuvant chemotherapy; Prognosis; Subtype
23.  Breast Microcalcifications: Diagnostic Outcomes According to Image-Guided Biopsy Method 
Korean Journal of Radiology  2015;16(5):996-1005.
To evaluate the diagnostic outcomes of ultrasonography-guided core needle biopsy (US-CNB), US-guided vacuum-assisted biopsy (US-VAB), and stereotactic-guided vacuum-assisted biopsy (S-VAB) for diagnosing suspicious breast microcalcification.
Materials and Methods
We retrospectively reviewed 336 cases of suspicious breast microcalcification in patients who subsequently underwent image-guided biopsy. US-CNB was performed for US-visible microcalcifications associated with a mass (n = 28), US-VAB for US-visible microcalcifications without an associated mass (n = 59), and S-VAB for mammogram-only visible lesions (n = 249). Mammographic findings, biopsy failure rate, false-negative rate, and underestimation rate were analyzed. Histological diagnoses and the Breast Imaging Reporting and Data System (BI-RADS) categories were reported.
Biopsy failure rates for US-CNB, US-VAB, and S-VAB were 7.1% (2/28), 0% (0/59), and 2.8% (7/249), respectively. Three false-negative cases were detected for US-CNB and two for S-VAB. The rates of biopsy-diagnosed ductal carcinoma in situ that were upgraded to invasive cancer at surgery were 41.7% (5/12), 12.9% (4/31), and 8.6% (3/35) for US-CNB, US-VAB, and S-VAB, respectively. Sonographically visible lesions were more likely to be malignant (66.2% [51/77] vs. 23.2% [46/198]; p < 0.001) or of higher BI-RADS category (61.0% [47/77] vs. 22.2% [44/198]; p < 0.001) than sonographically invisible lesions.
Ultrasonography-guided vacuum-assisted biopsy is more accurate than US-CNB when suspicious microcalcifications are detected on US. Calcifications with malignant pathology are significantly more visible on US than benign lesions.
PMCID: PMC4559796  PMID: 26357494
Mammography; Calcification; Ultrasonography; Core needle biopsy; Image-guided biopsy
24.  Cardiac Magnetic Resonance Scar Imaging for Sudden Cardiac Death Risk Stratification in Patients with Non-Ischemic Cardiomyopathy 
Korean Journal of Radiology  2015;16(4):683-695.
In patients with non-ischemic cardiomyopathy (NICM), risk stratification for sudden cardiac death (SCD) and selection of patients who would benefit from prophylactic implantable cardioverter-defibrillators remains challenging. We aim to discuss the evidence of cardiac magnetic resonance (CMR)-derived myocardial scar for the prediction of adverse cardiovascular outcomes in NICM. From the 15 studies analyzed, with a total of 2747 patients, the average prevalence of myocardial scar was 41%. In patients with myocardial scar, the risk for adverse cardiac events was more than 3-fold higher, and risk for arrhythmic events 5-fold higher, as compared to patients without scar. Based on the available observational, single center studies, CMR scar assessment may be a promising new tool for SCD risk stratification, which merits further investigation.
PMCID: PMC4499533  PMID: 26175568
Non-ischemic cardiomyopathy; Sudden cardiac death; Cardiac magnetic resonance
25.  Korean Guidelines for Interventional Recanalization of Lower Extremity Arteries 
Korean Journal of Radiology  2015;16(4):696-722.
Peripheral arterial occlusive disease caused by atherosclerosis can present with intermittent claudication or critical limb ischemia. Proper diagnosis and management is warranted to improve symptoms and salvage limbs. With the introduction of new techniques and dedicated materials, endovascular recanalization is widely performed for the treatment of peripheral arterial occlusive disease because it is less invasive than surgery. However, there are various opinions regarding the appropriate indications and procedure methods for interventional recanalization according to operator and institution in Korea. Therefore, we intend to provide evidence based guidelines for interventional recanalization by multidisciplinary consensus. These guidelines are the result of a close collaboration between physicians from many different areas of expertise including interventional radiology, interventional cardiology, and vascular surgery. The goal of these guidelines is to ensure better treatment, to serve as a guide to the clinician, and consequently, to contribute to public health care.
PMCID: PMC4499534  PMID: 26175569
Guideline; Peripheral arterial disease; Diagnosis and management; Intervention

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