pediatric 13:30 - 18:00 grand ballroom 104kcr2018/down/abstract_book/scientific... ·...

Pediatric 411

Pediatric Sep 12, Wed

Pediatric 13:30 - 18:00 Grand Ballroom 104

Essential of pediatric radiology

Chairperson(s)Gye Yeon Lim The Catholic University of Korea,

Yoeuido St. Mary's Hospital, KoreaYong-Woo Kim Pusan National University Yangsan

Hospital, Korea

MC 03 PD-01 13:30-14:00

Congenital anomalies of kidneys and urinary tract

François Chalard Hospital Armand Trousseau, France.

[email protected]

MC 03 PD-02 14:00-14:20

Imaging UTI in children: Is VUR still relevant?

MichaelDitchfield MonashChildren’sHospital,MonashUniversity,

[email protected]

MC 03 PD-03 14:20 Value of structured report form for appendix US in pediatric patients: Can we reduce negative appendectomy and additional CT?Hyunjin Kim Bundang Jesaeng General Hospital, Korea. [email protected]

PURPOSE: To eva luate the ra te o f negat ive (unnecessary) appendectomy and additional CT exams after structured report (SR) versus free text report (FTR) for ultrasound (US) exams in pediatric patients with suspected appendicitis.MATERIALS AND METHODS: Between January 2009 to June 2016, 1150 pediatric patients with suspected appendicitis who underwent appendix US were included. On November 2012, we deployed a SR form delivering

the likelihood of appendicitis in a 5-point Likert scale forappendixUS.Thepatientswereclassified intotwogroups according to the US report form (SR and FTR). The patients of each groups were categorized into three grades according to the likelihood of appendicitis (1 = not appendicitis, 2 = equivocal appendix, and 3 = acute appendicitis) based on described US report. Primary outcome (negative appendectomy rate) and secondary outcome (percentage of additional CT exam following US to diagnose appendicitis) were compared between two groups.RESULTS: We identified 550 patients in the FTR group and 600 patients in the SR group. Negative appendectomy rates was decreased by 8.4% between two groups; 16.2% (19 of 117 patients) in FTR and 7.8% (8 of 102 patients) in SR (p = 0.028). And there was also decrease in the proportion of additional CT exam by 5.3% between two groups; 13.5% (74 of 550 patients) in FTR and 8.2% (49 of 600 patients) in SR (p = 0.003).CONCLUSION: Using the SR based on the likelihood of appendicitis for pediatric appendix US can decrease the rate of negative appendectomy and additional CT exam.

MC 03 PD-04 14:30Quantitative assessment of liver stiffness and perfusion using shear wave elastography and dual energy CT in hepatic veno-occlusive disease in rabbit modelJaeseung Shin1, Haesung Yoon1, Myung Joon Kim1, Mi-Jung Lee1, Yoon Jin Cha2, Kyunghwa Han1, Hyun Joo Shin1 1Severance Hospital, 2Gangnam Severance Hospital, Korea. [email protected]

PURPOSE: To know the usefulness of shear wave elastography (SWE) and dual energy computed tomography (DECT) for the diagnosis of hepatic veno-occlusive disease (VOD) in rabbit model.MATERIALS AND METHODS: Among six New Zealand white rabbits (3-4 kg, male), three rabbits had normal saline ingestion throughout 20 days and grouped as normal group. Another three rabbits had 6-thioguanine (6-TG, 5 mg/kg/day) ingestion throughout 20 days and grouped as VOD group. Liver stiffness was measured using supersonic shear wave imaging (SSI) on baseline, 3, 10, and 20th days. Liver perfusion was evaluated using DECT with fast kVp switching (80/140 kVp) on the same days. Three region-of-interests (ROIs) were drawn in liver parenchyma using monoenergetic images of 55, 70 keVs, water, and iodine maps. Morphologic changes of liver including periportal, gallbladder wall edema, or diameter change of hepatic veins were assessed on 20th day using CT. Final histologic score of VOD was

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evaluatedonthe21stdayaftersacrificeandcomparedbetween two groups using Mann-Whitney U test. Linear mixed model was used to know the differences of liver stiffness and perfusion parameters between two groups.RESULTS: Final histologic scores were significantly higher in VOD group than in normal group (median 22, 2, p = 0.046). There were no gross morphologic changes in the livers in CT. Using SWE, liver stiffness values were significantlyhigherinVODgroupcomparedwithnormalgroup (p = 0.003). Compared to baseline, liver stiffness values became significantly different from 3rd day in VOD group (p = 0.026), while it were not different during 20 days in normal group. Using DECT, CT attenuations, water, and iodine contents were significantly higher in VODgroupcomparedwithnormalgroup(allps<0.01).CONCLUSION: SWE and DECT could aid the diagnosis of hepatic VOD, while morphologic change was not apparent in the liver of animal model.

MC 03 PD-05 14:40Diagnostic value of gray-scale and Doppler US in venoocclusive disease after pediatric hematopoietic stem cell transplantation using the European Society for Blood and Marrow Transplantation CriteriaHeeyoung Chung, Soo Ah Im, Seongkoo Kim TheCatholicUniversityofKorea,SeoulSt.Mary’sHospital, Korea. [email protected]

PURPOSE: To determine the diagnostic value of gray-scale and Doppler ultrasonography (US) in hepatic veno-occlusive disease (HVOD) after hematopoietic stem cell transplantation (HSCT) using the new criteria from the European Society for Blood and Marrow Transplantation (EBMT).MATERIALS AND METHODS: Ninety-eight US exams of 62 pediatric patients who had gray-scale and Doppler US within 60 days of HSCT were studied retrospectively. Diagnose of HVOD was done clinically in both Baltimore and Seattle criteria and EBMT criteria. Patients were classified into two groups for further analysis: “high” group with EBMT grade 3/4 and “low or none” group with EBMT grade 0/1/2. For patients with multiple exams, firsttwoexamswereincluded.Portalveinvelocity,peaksystolic velocity (PSV) of hepatic artery, resistance index (RI) of hepatic artery, GB wall thickening, periportal edema and presence of splenomegaly and ascites were recorded and their relationship with development and severity of HVOD according to the EBMT criteria was analyzed. A scoring system was developed, appointing one point for each of portal vein velocity lower than 10 cm/s, PSV of HA exceeding 100 cm/s, RI of HA over 0.75, GB wall thickening of more than 4 mm, and the

presence of ascites.RESULTS: The incidence of HVOD was 54.8% (34/62) according to the Baltimore and Seattle criteria and 61.3% (38/62) according to the EBMT criteria, with all of the four additionally diagnosed patients in grade three in the EBMT criteria. In both criteria, non-HVOD group andHVODgroupshowedsignificantdifferenceinportalvein velocity, PSV of hepatic artery, RI of hepatic artery, GB wall thickening and presence of ascites. There was nosignificantdifferenceinsplenomegalyandperiportaledema. All patients with portal vein velocity less than 10 cm/s was in EBMT 3/4 grades. The scoring system had good (0.813) area under the curve (AUC) for diagnosing HVOD, and fair (0.734) AUC for detecting EBMT grade 3/4 in ROC curve. With cut-off value of 1.5, the positive predictive value (PPV) for diagnosing HVOD was 87.5%, and PPV for EBMT grade 3/4 was 75.4%.CONCLUSION: Gray-scale and Doppler US is useful in diagnosing and detecting more severe form of HVOD in pediatric HSCT patients.

MC 03 PD-06 14:50Quantitative evaluation of denervated muscles in brachial plexus birth injury (BPBI) using T2 relaxation time mappingMi-Jung Lee1, Alexandra Plemmons2, Roger Cornwall3, Kendra Eckstein3, Hee Kyung Kim3 1Severance Hospital, Yonsei University College of Medicine, Korea, 2University of Cincinnati College of Medicine, USA, 3CincinnatiChildren’sHospitalMedicalCenter, USA. [email protected]

PURPOSE: To evaluate the T2 relaxation times of shoulder muscles in children with brachial plexus birth injury (BPBI) as they relate to glenohumeral dysplasia and shoulder function.MATERIALS AND METHODS: This retrospective study included children with unilateral BPBI who underwent bilateral shoulder 1.5T or 3T MRI. On axial images, mean T2 relaxation times were measured in the deltoid, subscapularis, and infraspinatus muscles. Glenoid retroversion and posterior humeral head displacement were measured, and glenohumeral dysplasia was classifiedbymodifiedWatersgrade.Shoulderfunctionmeasured by the Mallet Scale and Active Movement Scale (AMS) was evaluated in the subset of patients in whom an MRI and clinical examination were available prior to any surgery and less than 4 months apart. Relationships among all imaging and clinical data were assessed with Pearson correlations for continuous variablesandKendall’sTau-bforcategoricalvariables.T2 values were compared between sides with paired t-tests.

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RESULTS: 74 children (age, 5-216 months; mean, 66 months) were included. Age did not correlate with muscle T2 values in both sides. T2 values of all shoulder muscles were significantly higher on the affected side (allps<0.001)andpositivelycorrelatedwithmodifiedWaters grade (tau = 0.22, p = 0.016 in deltoid; tau = 0.21, p = 0.019 in subscapularis; and tau = 0.18, p = 0.039 in infraspinatus). In the clinical subset (n = 24), muscle T2 values did not correlate with global shoulder function on the Mallet scale, but individual muscle T2 values correlated inversely with corresponding specific AMS shoulder functions (tau = -0.33, p = 0.036 for deltoid/abduction; tau= -0.55,p<0.001 for infraspinatus/external rotation).CONCLUSION: Shoulder muscle T2 relaxation time does not change with age, but is affected by BPBI and correlates with glenohumeral dysplasia and clinical muscle function.


Essential of pediatric radiology

Chairperson(s)Ji Hye Kim Samsung Medical Center, Sungkyunkwan

University School of Medicine, KoreaChoon Sik Yoon Gangnam Severance Hospital,

Yonsei University College of Medicine, Korea

MC 03 PD-07 15:20-15:50

Imaging bone marrow in children

MichaelDitchfield MonashChildren’sHospital,MonashUniversity,

[email protected]

MC 03 PD-08 15:50 Kimura’s disease in children and young adults: Clinical and radiologic featuresHaewon Kim, So-Young Yoo, Ji Hye Kim, Tae Yeon Jeon, Saelin Oh Samsung Medical Center, Korea. [email protected]

PURPOSE: To describe the clinical and radiologic featuresofKimura’sdisease(KD)inchildrenandyoungadults,whichisararechronicinflammatorydisorderandoften presents as a diagnostic challenge.MATERIALS AND METHODS: We retrospectively reviewed 17 patients (M:F = 16:1, mean age, 13.5; range, 9-20 years) with pathologically confirmed KD over 18 years in a tertiary center in South Korea. Lesion characteristics were assessed in terms of location, laterality, multiplicity, margin and presence of regional lymphadenopathy in the available imaging studies including US, CT and MR. Clinical features were also reviewed.RESULTS: All patients presented with a palpable, non-tender soft tissue mass or localized swelling. The majority was located in the head and neck (n = 14), while the upper extremity (n = 4) and the inguinal area (n = 1) were also affected. Out of the head and neck lesions (n = 14), the parotid gland (n = 7, 50%) was the most commonly involved, followed by the lacrimal gland (n = 3, 21%), cheek (n = 3, 21%), retroauricular area (n = 2, 14%) and scalp (n = 1, 4%). Bilaterality (41%) and multiplicity (53%) was a common feature as well as regional lymphadenopathy (47%). The margin of the masses was well-defined in 12 (71%); ill-defined in 5 (29%)withadjacentfatinfiltration.ThediagnosisofKDwas radiologically suspected only in 6 (35%), and the differential included lymphoma, venous malformation and pseudotumor. Varying degree of peripheral eosinophilia was present in most of the patients as well as increased serum IgE. Treatment was done by surgical resection in all, with additional chemoradiation in 3 (18%). Recurrence was noted in 9 (53%).CONCLUSION: Although rare, awareness of clinical and imaging features in KD can help early diagnosis and appropriate management in the patients presented with palpable masses.

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MC 03 PD-09 16:00Phase-sensitive inversion recovery using multiparametric quantitative MRI improves the evaluation of myelination in infantsHyun Gi Kim1, Jin Wook Choi1, Miran Han1, Sung-Min Gho2 1Ajou University Hospital, 2GE Healthcare Korea, Korea. [email protected]

PURPOSE: Phase-sensit ive inversion recovery (PSIR) is a T1-weighted inversion recovery sequence with phase-sensitive reconstruction. Multiparametric quantitative MRI can create PSIR in addition to other contrast-weighted images. The purpose of this study was to show the usefulness of PSIR in evaluating myelination degree in infants.MATERIALS AND METHODS: Infants without visible brain parenchymal abnormality on MRI were included in this retrospective study. The brain MRI protocol included PSIR, T1-weighted image (T1WI), and fast spoiled gradient-echo (FSPGR). PSIR and T1WI were created from multiparametric quantitative MRI. By drawing region of interests, signal intensity values of unmyelinated white matter (uWM), myelinated WM (mWM), and cortical gray matter (GM) were measured. With the values, the contrast between uWM-mWM and uWM-GM were calculated using Michelson Contrast equation. Visual assessment of the degree of myelination was done between the sequences.RESULTS: Total of 91 infants (age, 51 ± 47 days; range, 1-180 days) were included. The means and standard deviations of uWM-mWM contrast values using PSIR, T1WI, and FSPGR were 0.510 ± 0.016, 0.190 ± 0.009, and 0.253 ± 0.008, respectively. The contrast values ofuWM-mWMweresignificantlydifferent,showingthehighestcontrast inPSIR(p<0.001).Themeansandstandard deviations of uWM-GM contrast values using PSIR, T1WI, and FSPGR were 0.360 ± 0.021, 0.094 ± 0.006, and 0.098 ± 0.011, respectively. The contrast valuesofuWM-GMweresignificantlydifferent,showingthehighestcontrast inPSIR (p<0.001).Onvisualassessment, there was improved visualization of the myelination using PSIR.CONCLUSION: PSIR, which can be created from multiparametric quantitative MRI, improves contrast between myelinated and unmyelinated structures. PSIR may enhance our diagnostic performance to detect myelination patterns in the infants' brain.

MC 03 PD-10 16:10-16:30

Organelle-based leukodystrophy

In-One KimSeoul National University College of Medicine, Korea.

[email protected]

MC 03 PD-11 16:30Brain alteration in neonates with congenital heart disease using apparent diffusion coefficient histogramsMeiJiao Zhu Children’sHospitalofNanjingMedical,[email protected]

PURPOSE: To evaluate the value of quantitative analysis of apparent diffusion coefficient (ADC) histogram in brain in neonates with congenital heart disease (CHD).MATERIALS AND METHODS: Pre-operative ADC maps of MR imaging of newborns confirmed with septal defect CHD were retrospectively analyzed in our Hospital (60 cases; 38 male; mean age, 10.45 days; range, 1-15 days). ADC maps of normal neonates were enrolled as normal control (22 cases; 14 male; mean age, 8.64 days; range, 1-15 days). ADC map slice was chosen at the level of the anterior and posterior horn of lateral ventricle, and the whole brain area ADC histogram was calculated on the same slice using MRIcron and Python softwares. The histogram features were analyzed and the histogram parameters were obtained, including the ADC values for each percentage, ADC mean, ADC min, ADC peak, as well as the ADC histogram Curve skewness, kurtosis, entropy and variance. The correlation between the gestational age of two groups and ADC histogram values were calculated respectively. Then independent-samples t test was used to differentiate two groups using histogram metrics. Finally, the diagnostic efficacy of different parameters was analyzed using the receiver operating characteristic curve.RESULTS:Therewasasignificantcorrelationbetweenthe histogram metrics and neonatal gestational age in the two groups, except for ADC mean, ADC min andADCpeak (p<0.05).Andwith the increaseofgestational age, the values of all parameters decreased linearly. At the same time, the ADC parameters excluding ADC min of CHD groups were greater than those of the control group, and there was a statistical

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difference in the 70th-95th ADC, skewness, kurtosis and variance(p<0.05)betweenthetwogroups.Theareaunder the curve for the 90th ADC value was the largest, which was 0.698.CONCLUSION: The ADC histogram can quantify and objectively provide more quantitative information of brain development in neonates with CHD. It is a rapid and clinically feasible quantitative method to identify their brain changes. The 90th ADC is the most effective.

MC 03 PD-12 16:40Neural mechanism of second language processing in Korean-English bilingual childrenYun Young Lee1, Woong Yoon1, Seul Kee Kim2, Byung Hyun Baek1, Chung-Man Moon3 1Chonnam National University Hospital, 2Chonnam National University Hwasun Hospital, 3Chonnam National University Advanced Institute of Aging Science, Korea. [email protected]

PURPOSE: To evaluate the neural mechanism associated with second language processing in Korean-English bilingual children by comparing neurofunctional areasand its’ activitiesduringL1 (Korean)andL2(English) processing using functional magnetic resonance imaging.MATERIALS AND METHODS: Twenty Korean

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elementary school chi ldren (4-6th grade) were participated in this study. All were native speaker of Korean and were learning English as a foreign language. Functional brain images were acquired during a short passage comprehension task in each of Korean and English languages of high, intermediate and low taskdifficulty.Thebrainactivationareaswereanalyzedaccording to the languages, task difficulty and English proficiency.RESULTS: Significantly increasedactivitieswerenotedduring performance of English passage comprehension task in the regions of the dorsolateral prefrontal cortex, supplementary motor area, precentral gyrus, left basal ganglia, left parietotemporal lobe and occipital lobe compared to Korean passage comprehension task. Low English proficiency group showed significantly higher activities in frontotemporal cortical region including prefrontalcortexcomparedwithhighproficiencygroup.More brain activities were noted in right inferior frontal gyrus and right temporoparietal lobe during performance ofintermediatelevelofEnglishtaskdifficultycomparedwith low level of task difficulty. However, there were significantly decreased brain activities in case of high leveloftaskdifficulty.CONCLUSION:Brainactivation increasedsignificantlywhen performing English task compared to Korean task, inlowerEnglishproficiencygroup,andwhenperforminghigher level of task difficulty. However, it was found that the level of brain activity decreased when the task difficulty exceeds appropriate level of comprehender. These results suggest that proper level of education is important to learn second language in an EFL environment.

MC 03 PD-13 17:10In vivo proton MR spectroscopic imaging in pediatric brain: A virtual biopsy using metabolites to differentiate neoplastic and non-neoplastic intracranial lesionsDhananjaya Kotebagilu Narayana Vamyanmane1, Dayanath Srinivasan2, Nidhi Leekha3, Chinky Patel4, Sindu Gowdar5, Ranjana Rajendra6 1Abhayahasta Multispeciality Hospital PVT Ltd., 2Medall Clumax Diagnostic Center, 3Ruby Hall Clinic Pune/Student of Texila American University, 4Sparsh Hospital, Bangalore, 5Mahaveer Jain Hospital, 6Manipal Hospital, [email protected]

PURPOSE: Differentiating and categorizing neoplastic lesionfromnon-neoplastic inflammatory/granulomatouslesions with the help of metabolites in magnetic resonance spectroscopic (MRS) imaging using single voxel or multivoxel at spin echo 30 ms and 135 ms.

MATERIALS AND METHODS: Pediatric patients with clinically suspected intracranial lesions underwent MRI and high-resolution proton MRS imaging before undergoing treatment. All intracranial lesions studied, showed abnormal signal intensity on MR imaging compared with normal parenchyma. MRS imaging applied on intracranial lesions.RESULTS: Intracranial neoplastic lesions studied, showed abnormal MR spectra compared with normal parenchyma. The pattern of MRS metabolites consisted of abnormally increased choline and decreased N-acetyl aspartate (NAA) resonances. The intracranial non-neoplastic lesions showed metabolites consisted of increased choline, inverted lactate or doublet peak, increased lipid, no reduction in N-acetyl aspartate (NAA) peak and decreased amino acids and creatinine (Cr).CONCLUSION: In vivo MRS imaging is noninvasive technique that gives relative concentrations of certain intracranial biochemical compounds. Intracranial neoplastic and non-neoplastic lesions are characterized by using spectrum of different metabolites and its ratios - virtual biopsy.

MC 03 PD-14 17:20Brain herniation into the transverse sinuses arachnoid granulations in the pediatric population investigated with 3T MRRecep Sade, Hayri Ogul, Gokhan Polat, BerhanPirimoglu,MecitKantarcıAtaturk University, Turkey. [email protected]

PURPOSE: To evaluate the frequency, radiological-clinical findings of brain herniation into arachnoid granulation (BHAG) in pediatric age group using 3 Tesla magnetic resonance imaging (MRI).MATERIALS AND METHODS: Patients who were under 18 age and underwent brain MRI examination which consist of 3D T1, 3D T2 FLAIR and 3D T2 sequences. A

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total 2320 patients enrolled in the study. All cases of AG into transverse sinus were included. The location of the AG, the deep, transverse, vertical and neck diameters andvolumeofAGwererecorded.Clinicalfindingsandimaging findings of patients were also recorded. The patients categorized as BHAG and AG without brain herniation (AGWBH). The mean diameters and volume of AG, age, sex, clinical findings and imaging findings were evaluated and compared in each group. RESULTS: 135 patients (71 female, 64 male) had AG in total 2320 patients (prevalence 5.81%). Fifteen patients (10.7%) had BHAG. The mean diameters (deep, transverse, vertical and neck) and volume of AGWBH were 5.23 ± 1.91 mm, 4.07 ± 1.58 mm, 4.99 ± 1.68 mm, 3.64 ± 1.84 mm and 85.05 ± 89.10 mm3, respectively. The mean diameters (deep, transverse, vertical and neck) and volume of BHAG were 7.46 ± 2.6 mm, 6.85 ± 2.34 mm, 8.32 ± 2.35 mm, 5.41 ± 1.79 mm and 331 ± 361.26 mm3, respectively. The mean diameters, and volumeofBHAGweresignificantlylargerthanAGWBH(p<0.001forallparameters).Therewasnosignificantdifference related to clinical and imaging findings between groups (p > 0.05). CONCLUSION: BHAG is seen in pediatric age group as frequently as adults. Its frequency is not related to age. It is not significantly associated with neurological symptoms. As the AG size increases, the risk of BHAG increases.

MC 03 PD-15 17:30Added values of bone unfolding images for detection of skull fracture in childrenSae Jin Park, Tae-Hyung Kim, Young Hun Choi Seoul National University Hospital, Korea. [email protected]

PURPOSE: Skull fracture could be a common finding after head trauma. It has a significant impact on prognosis. Various methods have been proposed to defect the skull fracture. This study was retrospectively conducted to see additional effect of the "unfolds" imaging technique.MATERIALS AND METHODS: 56 admitted patients with brain skull injury who underwent computed tomography (CT) between April 2010 and May 2017 were analyzed. Retrospectively, post processing procedure was performed. McNemar test and Mann-Whitney U-test were used for statistical analysis.RESULTS: For al l readers, sensit ivi ty was not statisticallysignificant,althoughonereaderhadahigherpercentage in routing bone window (RBW) images plus bone unfolding images than the RBW images (p = 0.755). Also, there was no statistically difference in accuracy between the two (p = 0.954). However, RBW plus bone unfoldingimagesweresignificantlyhigherinconfidencescore and less time taken (p = 0.001) than RBW images, regardless of the presence or absence of fracture.CONCLUSION: Bone unfolding images could help in reducing the interpretation time and also enhancing theconfidencelevelof theradiologisttodeterminethepresence or absence of fracture in the pediatric age group.

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MC 03 PD-16 17:40Frequency selective non-linear blending technique can improve detection of acute infarcts on pre-enhanced brain CT in childrenSeunghyun Lee1, Young Hun Choi1, Yeon-Jin Cho1, Jung-Eun Cheon1, Woo Sun Kim2, In-One Kim2 1Seoul National University Hospital, 2Seoul National University College of Medicine, Korea. [email protected]

PURPOSE: To evaluate whether the frequency selective non-linear blending (“best contrast”/BC) technique can improve the detection of acute infarction on non-enhanced brain CT (NECT) in children.MATERIALS AND METHODS: From January 2014 to December 2017, 44 children with moyamoya disease (18 boys and 26 girls; mean age, 8.8 ± 3.6 years) underwent NECT followed by diffusion MRI for suspected postoperative ischemic complications. NECT images were post-processed using BC for enhanced delineation of infarction. Subjective detection rates of hypodense infarctions were calculated with original NECT images and processed BC images. Contrast-to-noise ratios (CNRs) between infarcted area and gray matter and between normal cortex and white matter were calculated.RESULTS: Twenty-one of 44 children was confirmed with acute infarction through diffusion MRI. Detection rate of infarction was 61.9% (13/21) and 38.1% (8/21) on BC and NECT images, respectively. CNR was improved with BC (BC vs. NECT; 6.7 ± 1.8 vs. 2.9 ±

0.8 for infarcted area, and 5.6 ± 1.1 vs. 2.8 ± 0.6 for the normalgrayandwhitematter,allps<0.05).CONCLUSION: BC technique can improve the detectability of infarction on NECT by improving tissue contrast in children.CLINICAL RELEVANCE: Frequency-selective non-linear blending technique improves detection of brain infarction in moyamoya disease patients and it seems to be particularly valuable for implementation in CT systems not equipped for dual-energy or spectral CT imaging.

MC 03 PD-17 17:50 Virtual standard dose CT images from low-dose CT through generative adversarial network-based deep learning approachSun Kyoung You1, Jeong Eun Lee1, Hyoung Suk Park2, Kiwan Jeon2 1Chungnam National University Hospital, 2National Institute for Mathematical Sciences, Korea. [email protected]

PURPOSE: To evaluate the clinical feasibility of a virtual 120 kilovoltage (kVp) image made from an 80 kVp image of pediatric abdominal and pelvic computed tomography (APCT) through a generative adversarial network (GAN)-based deep learning approach.MATERIALS AND METHODS: We train a GAN based model that enables the 80 kVp image-to-120 kVp image

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transformation with unpaired 80 kVp and 120 kVp images. To preserve the morphological structure of 80 kVp image, the proposed model includes an additional penalty that enforces similarities between 80 kVp and corresponding virtual 120 image. We retrospectively reviewed the clinical data and imaging findings of children who underwent APCT using 64-channel multidetector CT scanner in the emergency room. Total 82lowdoseAPCT(fixed80kVpand100mAsreferencetubecurrent)and65conventionalAPCT(CCT;fixed120kVp and 200 mAs reference tube current) were included in our study. We prepared a data set by selecting 20 dicomfilesthatcontaintheportalveinandliverforeachpatients. The dataset of 42 patients from LDCT and 42 patients from CCT were used for training of GAN. Other datasets of 41 patients from LDCT were used for create virtual 120 kVp images (VI) as original 80 kVp images (OI). Quantitative and qualitative image analyses were performed by two radiologists to compare the OI and VI.RESULTS: The mean CT number of the portal vein, liver, psoas muscles and the mean image noise in ROI werehigher than inVI (p<0.001, respectively).Themean CNR of the main portal vein, the mean SNR of the portal vein and the liver of VI were higher than in OI (p <0.001,p<0.001,p=0.001,respectively).Qualitativeanalysis showed no significant difference between the two groups with substantial agreement between the reviewers.CONCLUSION: GAN-created virtual image can be applied to conventional CT scanner, which cannot be applied high-end dose reducing program, and this is expected to be able to be extended to other areas of low dose CT. Our study suggest new direction of low dose CT research using deep learning algorithm.


Current issues in pediatric imaging

Chairperson(s)Yun woo Chang Soonchunhyang University College

of Medicine, KoreaHong Eo Samsung Medical Center, Sungkyunkwan

University School of Medicine, Korea

SS 06 PD-01 08:00Predicting portal hypertension and esophageal varices using spleen MR elastography in pediatric liver fibrosisHaesung Yoon, Mi-Jung Lee, Hyun Joo Shin, Myung Joon Kim Severance Hospital, Korea. [email protected]

PURPOSE: To assess the utility of spleen stiffness measurement by MR elastography (MRE) to evaluate portal hypertension and predict esophageal varices in children compared with laboratory index (aspartate aminotransferase to platelet ratio index, APRI) and spleen size.MATERIALS AND METHODS: We retrospectively reviewed abdominal MRE images underwent on a 3T system in pediatric patients and selected patients with previous Kasai operation from biliary atresia as a Kasai group and patients with normal liver and spleen as a normal group. Two-dimensional spin-echo echo-planar MRE acquisition was performed centered on the liver with a pneumatic driver using 60 Hz with low amplitude. Laboratory results within six months interval with MRE and normalized spleen size ratio using upper normal size limit were also evaluated. All Kasai group patients underwent gastroesophageal endoscopy during routine follow-up. Mann-Whitney U test, Spearman correlation and diagnostic performance analysis using area under the curve (AUC) were performed for statistical analysis.RESULTS: The median value of spleen MRE was 6.1 kPa in the normal group (n = 9, age 9-18 years, range 4.9-6.8 kPa) and 9.2 kPa in the Kasai group (n = 22, age 4-18 years, range 4.9-17.3 kPa). In the Kasai group, spleen size ratio, APRI and spleen MRE values were higher in patients with portal hypertension (n = 11) comparedtopatientswithout(n=11)(allps<0.001)and in patient with esophageal varices (n = 7) compared topatientswithout(n=15)(allps<0.03),eventhoughliver MRE values were not different. Spleen MRE values correlatedwithspleensizeratio(r=0.715,p<0.001)andAPRI(r=0.769,p<0.001),butnotwithliverMRE

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values. The AUC of spleen MRE in predicting portal hypertension was 0.938 with cut-off value of 8.8 kPa, 91%sensitivityand82%specificityandthatinpredictingesophageal varices was 0.852 with cut-off of 10.3 kPa, 86%sensitivityand80%specificity.CONCLUSION: The median value of normal spleen MRE was 6.1 kPa with maximum of 6.8 kPa in children. Spleen MRE could predict portal hypertension using cut-off of 8.8 kPa and esophageal varices using cut-off of 10.3 kPa in biliary atresia patients after Kasai operation.

SS 06 PD-02 08:10Diagnostic performance of transient elastography and supersonic shear wave elastography for monitoring of hepatic fibrosis in children with biliary atresia after Kasai operationJisun Hwang, Hee Mang Yoon, Ah Young Jung, Jin Seong Lee, Young Ah Cho Asan Medical Center, [email protected]

PURPOSE: To evaluate diagnostic performance of liver stiffness (LS) measured by supersonic shear wave elastography (SWE), and transient elastography (TE) formonitoringhepaticfibrosisinpatientswhounderwentKasai operation for biliary atresia (BA).MATERIALS AND METHODS: We retrospectively identified47patients(mean±standarddeviation,9.76±6.68 years old; range, 11 months-21 years old) who had Kasai operation for BA underwent SWE and TE in the sameday.Thedegreeofhepaticfibrosiswasclassifiedinto three stages (I-III) according to the laboratory findings,morphologicchangeof livercirrhosis(LC)onUS, and clinical symptoms of cirrhosis (I: no evidence of LC, II: US or clinical signs of LC with compensated state; Child Pugh A, and III: decompensated LC; Child Pugh B, C).RESULTS: There were 13 patients in stage I, 17 patients in stage II, 17 patients in stage III. Median time interval between operation and US was 7.8 years. LS values measured by SWE and TE showed an increased tendency according to the clinical stage of the hepatic fibrosis.Asignificantpositivecorrelation(ρ=0.819,p<0.001)andamoderateagreement(ICC0.677,p<0.001)were found between LS values measured by SWE and TE. On Bland Altman analysis, mean difference and 95% limit-of-agreement between LS values measured by SWE and TE was 11.2% and ± 80.7% of mean LS values. On ROC analysis, TE and SWE showed comparable diagnostic performance for diagnosing LC (AUC 0.973 vs. 0.863; p = 0.06). For diagnosing decompensated LC, TE showed significantly higher diagnostic performance than SWE (AUC 0.910 vs. 0.800: p = 0.022).

CONCLUSION: Diagnostic performance of TE and SSWE for detection of compensated and decompensated LC was excellent, but TE showed significantly higher performance in diagnosing decompensated LC than SWE. The LS measurement using US elastography are potential noninvasive marker for postoperative monitoring in patients with BA. However, LS values measured by TE and SWE showed a wide range of difference; therefore, two techniques may not be used interchangeably.

SS 06 PD-03 08:20Reference T1 values of pediatric liver using a T1 mapping with MOLLI sequence at 1.5-T MRYeon-Jin Cho1, Younghun Choi1, SeungHyun Lee1, Jung-Eun Cheon1, Woo Sun Kim2, In-One Kim2 1Seoul National University Hospital, 2Seoul National University College of Medicine, Korea. [email protected]

PURPOSE: To determine T1 values of normal pediatric liver using Modified look-locker inversion recovery (MOLLI) sequence.MATERIALS AND METHODS: From March 2017 to February 2018, children with normal liver who underwent liver MRI including MOLLI sequence were included (n = 34). Children were considered to have normal liver, when patients had normal liver function tests and no evidence of fat or iron deposition in the liver nor focal liver lesions on MRI. The mean T1 relaxation time of the liver was obtained by drawing a region of interest in the right lobe of the liver on the T1 map. The measured T1 values were plotted against age and a regression equation that best explained the age dependence of T1 valueoftheliverwasidentified.RESULTS: The mean T1 relaxation time of 34 children (M:F = 12:22; median age, 6.8 ± 4.9 years; range, 2 month to 16 years) was 601.56 ± 70.22 ms (range, 499.15 to 833.21 ms). The T1 value of the liver decreased with increasing age (Pearson correlation coefficient,0.521;95%CI,-0.731to-0.223,p=0.002).The negative association was best explained by the logarithmic equation (T1 relation time = 653.434-83.537 × log (age, year) The T1 value of the liver changed the mostdynamicallywithinthefirstyearoflife.CONCLUSION: Our study demonstrated an age-related change in the T1 value of the liver and provided the equation to predict the T1 relaxation time of the liver in relation to age, which may serve as the basis for assessment of hepatic parenchymal disease in children.

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SS 06 PD-04 08:30Usefulness of mono-, bi-, and stretched exponential model diffusion-weighted imaging for the differentiation of biliary atresia and non-biliary atresia in neonatal liver MRIJisoo Kim, Myung Joon Kim, Mi-Jung Lee, Haesung Yoon, Hyun Joo Shin Severance Hospital, Korea. [email protected]

PURPOSE: To know the usefulness of mono, bi, and stretched exponential model diffusion weighted imaging (DWI) for the differentiation of biliary atresia (BA) from non-biliary atresia (non-BA) in neonatal liver MRI.MATERIALS AND METHODS: Neonates who underwent liver MRI in the suspicion of BA due to hyperbilirubinemia from November 2017 to May 2018 were retrospectively included and divided as BA and non-BA groups. Liver MRI included DWI using 10 b-values (0, 25, 50, 75, 100, 150, 200, 400, 600, 800 s/mm2) at 1.5T. Free hand ROIs in the two representative axial images of liver avoiding major vessels were drawn to calculate the parameters using software and mean values were used. From monoexponential model,apparentdiffusioncoefficient(ADC)1usingtwob-values (0, 800 s/mm2) and ADC 2 using 10 b-values were obtained. From biexponential model, true diffusion coefficient (D), pseudo diffusion coefficient (D*), and perfusion fraction (f) were obtained. From stretched exponentialmodel,distributeddiffusioncoefficient(DDC)andwatermoleculardiffusionheterogeneity index(α)were obtained. Parameters were compared between BA and non-BA groups using Mann-Whitney U test. The diagnostic performances were assessed and compared using area under the curve (AUC) analysis.RESULTS: From fourteen neonates (mean 8.8 ± 3.1 weeks old, M:F = 7:7), ten neonates were in BA (mean 9.1 ± 3.3 weeks) and four neonates were in non-BA

groups (mean 8 ± 2.9 weeks). The ages of children in twogroupswerenotsignificantlydifferent(p=0.517).Among the parameters, ADC 1, ADC 2, D* and DDC values inthe liverweresignificantly lower inBAgroupcompared with non-BA group (p = 0.007, 0.011, 0.034, 0.011, respectively). Diagnostic performances of these parameters were all above 0.87, using ADC 1 (AUC 0.972,95%confidence interval [CI]0.728-1.000),ADC2 (AUC 0.950, 95% CI 0.691-1.000), D* (AUC 0.875, 0.593-0.988), and DDC (AUC 0.950, 0.691-1.000), withoutsignificantdifferences.CONCLUSION: NeonatesinBAgrouphadsignificantlylower ADC 1, ADC 2, D* and DDC values in the liver than in non-BA group. ADC value obtained with two b-values could sufficiently aid the differentiation of BA and non-BA, because the diagnostic performances of theses parameters were all good and not significantly different.

SS 06 PD-05 08:40Prospective role of plain radiography in intussusceptionEun Taeg Hwang, Hee Jung Lee, Mi Jeong Kim, Soo Hyun Yeo Keimyung University Dongsan Medical Center, Korea. [email protected]

PURPOSE: To evaluate role of plain radiograph in diagnosis of intussusceptions.MATERIALS AND METHODS: We evaluated abdominal radiograph of 228 children (mean 25.3 months, range 1-121 months) who underwent ultrasonography (113) or barium enema (115) under clinical assessment of intussusception. Radiographic analysis included the presence of the target sign, crescent sign, fecalith in the colon, and mechanical or paralytic ileus.RESULTS: Intussusception was diagnosed in 120 (52.6%) by ultrasonography (46, 40.7%) or barium enema (74, 64.3%). Radiographic f ind ings in intussusception were as follows; the target sign in 71 (59.2%), crescent sign in 28 (23.3%), fecalith in the colon in 5 (4.2%), and paralytic or mechanical ileus in 2 (1.7%). The most abnormal common findings in patients without intussusception were fecalilth in colon in 26 (24.1%) and target sign in 12 (11.1%), paralytic or mechanical ileus in 5 (4.6%). Diagnostic values of the target sign were sensitivity of 59%, specificity of 89%, positive predictive value of 86%, negative predictive value of 34%, and accuracy of 73%.CONCLUSION: Thetargetsignprovideshighspecificityof 89% and positive predictive value of 86% in diagnosis of intussusception.

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SS 06 PD-06 08:50Ipsilateral hypertrophy of the mastoid process in surgical cases of congenital muscular torticollisHyun Gi Kim, Shin-Young Yim Ajou University Hospital, Korea. [email protected]

PURPOSE: Congenital muscular torticollis (CMT) is one of the most common musculoskeletal diseases in newborns and secondary complication due to CMT is common. The purpose of this study was to show ipsilateral hypertrophy of the mastoid process in CMT subjects.MATERIALS AND METHODS: Preoperative CT of surgically treated CMT subjects and age- and gender-matched controls were collected. The volume of mastoid processes of both groups was calculated by drawing region of interests in the mastoid on CT axial images. Intra- and inter-group comparison of the mastoid process volume was done. In CMT group, linear regression test between the volume difference of the mastoid processes ([ipsilateral mastoid volume] - [contralateral mastoid volume]) and age was done.RESULTS: Total of 212 CMT subjects (age, 50.9 ± 44.3 months) and 212 controls (age, 50.4 ± 44.2 months) were included. In the CMT group, the ipsilateral mastoid process volume was significantly larger than the contralateral side (32.2 ± 30.3 cm3 vs. 21.8 ± 22.8 cm3, p<0.001).Inthecontrolgroup,therewasnosignificantdifference between the right and left mastoid process volume (21.6 ± 24.6 cm3 vs. 21.2 ± 23.8 cm3, p = 0.472). Theinter-groupcomparisonshowedsignificantly largeripsilateral mastoid process volume in the CMT group compared to mastoid process volumes of both sides inthecontrolgroup(p<0.001).Thepercentageofthevolumetric asymmetry was 9.3 (75/8) times greater in the CMT group compared to the control group. Regression analysisshowedthesignificantcorrelationbetweenthevolume difference of the mastoid processes and age in the CMT group (adjusted R2=0.286,p<0.001).CONCLUSION: CMT subjects showed ipsilateral hypertrophy of the mastoid process and the volumetric asymmetry increased with age. Ipsilateral hypertrophy of the mastoid process should be considered one of the skeletal complications of CMT.

Fig. 1a. TE results according to stages.

Fig. 1b. SWE results according to stages.

Fig. 2. Correlation analysis between TE and SWE.

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Fig. 3. Bland-Altman analysis: Agreement between LS values between TE and SWE.

Fig. 4. AUROC for TE and SWE in assessing liver cirrhosis(Stage≥2).

Fig. 5. AUROC for TE and SWE in assessing decompensatedlivercirrhosis(Stage≥3).

SS 06 PD-07 09:00Is it better to enter a volume CT dose index value before or after scan range adjustment for radiation dose optimization of pediatric cardiothoracic CT with tube current modulation?Hyun Woo Goo Asan Medical Center, University of Ulsan College of Medicine, [email protected]

PURPOSE: To determine whether the body size-adapted volume CT dose index (CTDIvol) in pediatric cardiothoracic CT with tube current modulation is better to be entered before or after scan range adjustment for radiation dose optimization.MATERIALS AND METHODS: In 83 pat ients, cardiothoracic CT with tube current modulation was performed with the body size-adapted CTDIvol entered after (group 1, n = 42) or before (group 2, n = 41) scan range adjustment. Patient-related, radiation dose, and image quality parameters were compared and correlated between the two groups.RESULTS: The CTDIvol after the CT scan in group 1 wassignificantlyhigherthanthat ingroup2(1.7±0.1mGyvs.1.4±0.3mGy;p<0.0001.Imagenoise(4.6± 0.5 HU vs. 4.5 ± 0.7 HU) and image quality (1.5 ± 0.6 vs.1.5±0.6)showednosignificantdifferencesbetweenthe two (p > 0.05). In both groups, all patient-related parameters, except body density, showed positive correlations (r=0.49-0.94;p<0.01)with theCTDIvol

before and after the CT scan. The CTDIvol after the CT scan showed modest positive correlation (r = 0.49; p ≤0.001)with imagenoiseingroup1butnosignificant

pediatric 13:30 - 18:00 grand ballroom 104kcr2018/down/abstract_book/scientific... ·...

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