Anatomic consideration of the radial nerve in relation to humeral length for unilateral external fixation: a retrospective study using magnetic resonance imaging findings in korean.

BACKGROUND: This study aimed to present a safe zone for distal pin insertion for external fixation using magnetic resonance imaging (MRI) images. METHODS: All patients who took at least one upper arm MRI from June 2003 to July 2021 were searched via a clinical data warehouse. For measuring the humerus length, proximal and distal landmarks were set as the highest protruding point of the humeral head and lowermost margin of ossified bone of the lateral condyle, respectively. For children or adolescents with incomplete ossification, the uppermost and lowermost ossified margin of the ossification centers were set as proximal and distal landmarks respectively. The anterior exit point (AEP) was defined as the location of the radial nerve exiting the lateral intermuscular septum to the anterior humerus and distance between the distal margin of the humerus and AEP was measured. The proportions between the AEP and full humeral length were calculated. RESULTS: A total of 132 patients were enrolled for final analysis. The mean humerus length was 29.4 cm (range 12.9-34.6 cm). The mean distance between the ossified lateral condyle and AEP was 6.6 cm (range 3.0-10.6 cm). The mean ratio of the anterior exit point and humeral length was 22.5% (range 15.1-30.8%). The minimum ratio was 15.1%. CONCLUSION: A percutaneous distal pin insertion for humeral lengthening with an external fixator may be safely done within 15% length of the distal humerus. If pin insertion is required more proximal than distal 15% of the humeral shaft, an open procedure or preoperative radiographic assessment is advised to prevent iatrogenic radial nerve injury.

Characterization of Kikuchi-Fujimoto Disease in Children and Risk Factors Associated with Its Course.

OBJECTIVE: To outline the characteristics of Kikuchi-Fujimoto disease (KFD) in children and analyze factors associated with severe and recurring courses. METHODS: Electronic medical records of children histopathologically diagnosed with KFD at Seoul National University Bundang Hospital from March 2015 to April 2021 were retrospectively reviewed. RESULTS: A total of 114 cases (62 males) were identified. The mean patient age was 12.0 ± 3.5 years. Most patients came to medical attention with cervical lymph node enlargement (97.4%) and fever (85%); 62% had a high-grade fever (≥39°C). Prolonged fever (≥14 days) was seen in 44.3% and was associated with a high-grade fever (P = .004). Splenomegaly, oral ulcer, or rash was present in 10.5%, 9.6%, and 15.8%, respectively. Laboratory findings showed leukopenia, anemia, and thrombocytopenia in 74.1%, 49%, and 24%, respectively. Sixty percent of cases had a self-limited course. Antibiotics were initially prescribed in 20%. A corticosteroid was prescribed in 40% of patients and was associated with oral ulcer (P = .045) and anemia (P = .025). Twelve patients (10.5%) had a recurrence with a median interval of 19 months. No risk factor for recurrence was identified in multivariable analysis. Clinical characteristics of KFD were similar between our current and previous studies. However, antibiotics use decreased (P < .001); nonsteroidal anti-inflammatory drugs use increased (P < .001), and, although statistically not significant, corticosteroid treatment also increased. CONCLUSIONS: Over a span of 18 years, the clinical characteristics of KFD did not change. Patients presenting with high-grade fever, oral ulcer, or anemia may benefit from corticosteroid intervention. All patients should be monitored for recurrence.

Clinical course in children with equivocal appendicitis on computed tomography: a retrospective cohort study.

Purpose: Appendectomy is one of the most common surgeries in children. Although various radiological examinations are performed, they do not always reveal a definitive diagnosis of appendicitis. This study aimed to investigate the clinical course of equivocal appendicitis, identify the factors associated with appendectomy, and suggest appropriate management for these patients. Methods: Patients younger than 19 years who visited Seoul National University Bundang Hospital with a differential diagnosis of appendicitis from January 2013 to December 2017 were included. All participants conducted 'appendiceal CT' with a scoring scale of 1-5. The higher the score, the higher the likelihood of a radiologic diagnosis of appendicitis. We defined the appendicitis CT score of 2-4 as equivocal appendicitis (n = 143). Medical records were reviewed retrospectively for demographics, further examination as abdominal ultrasonography, and appendectomy status (yes or no). The mean follow-up period was 15.6 ± 71 days. Results: Equivocal appendicitis accounted for 16.7%. Additional ultrasonography test was performed in 24.5% (35 of 143). In total, 34 patients (23.8%) underwent appendectomy. Among the patients with appendiceal CT scores 2, 3, and 4, 4.9%, 50.0%, and 87.5% underwent appendectomy, respectively. Higher WBC count, higher appendicitis CT score, and readmission were significantly associated with appendectomy in patients with equivocal appendicitis. Conclusion: Higher appendicitis CT score and WBC level were positively associated with appendectomy. Careful observation can be a treatment option in appendicitis CT score 2 or 3 groups. Appendectomy is the first-line treatment for patients with appendicitis score 4. Additional ultrasonography test is advisable to determine treatment modality for equivocal appendicitis.

Improvement of Lutein and Zeaxanthin Production in Mychonastes sp. 247 by Optimizing Light Intensity and Culture Salinity Conditions.

In this study, we sought to improve lutein and zeaxanthin production in Mychonastes sp. 247 and investigated the effect of environmental factors on lutein and zeaxanthin productivity in Mychonastes sp. The basic medium selection and N:P ratio were adjusted to maximize cell growth in one-stage culture, and lutein and zeaxanthin production conditions were optimized using a central composite design for two-stage culture. The maximum lutein production was observed at a light intensity of 60 µE/m2/s and salinity of 0.49%, and the maximum zeaxanthin production was observed at a light intensity of 532 µE/m2/s and salinity of 0.78%. Lutein and zeaxanthin production in the optimized medium increased by up to 2 and 2.6 folds, respectively, compared to that in the basic medium. Based on these results, we concluded that the optimal conditions for lutein and zeaxanthin production are different and that optimization of light intensity and culture salinity conditions may help increase carotenoid production. This study presents a useful and potential strategy for optimizing microalgal culture conditions to improve the productivity of lutein and zeaxanthin, which has applications in the functional food field.

Transperineal ultrasonography for treatment response evaluation in children with perianal Crohn's disease.

PURPOSE: This study assessed the performance of transperineal ultrasonography (TPUS) in evaluating the treatment response in children with perianal Crohn's disease (PACD) compared with pelvic magnetic resonance imaging (MRI). METHODS: This retrospective study was approved by the Institutional Review Board of our institution, which waived the requirement for informed consent. Twenty-nine patients (19 boys and 10 girls; median age, 14 years [range, 8 to 18 years]) with 56 fistulas were examined. Each fistula's thickness and abscess size were measured using both modalities, and treatment response was classified as positive or negative based on each modality. The concordance of the classifications was compared between TPUS and pelvic MRI. A receiver operating characteristic curve (ROC) was used to evaluate the performance of TPUS. RESULTS: TPUS found 80.4% (45/56) of the fistulas. On MRI, 39 fistulas (70%) were classified as having positive treatment responses, and the remaining 17 as having no response. The agreement of the classifications between TPUS and MRI was moderate (κ=0.486; P<0.001; Spearman ρ=0.573; P<0.001). Based on the ROC analysis with the MRI findings as a reference to distinguish positive from negative treatment responses, TPUS exhibited sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 63.3%, 93.3%, 95.0%, 56.0%, and 73.3%, respectively. CONCLUSION: TPUS can be an appropriate adjuvant imaging modality for pelvic MRI to evaluate the treatment response of PACD in children when initial TPUS detects PACD with a location and imaging features comparable to those visualized on MRI.

A preliminary study of shear-wave elastography for the evaluation of varicocele in adolescents and young adults.

PURPOSE: The purpose of this study was to use shear-wave elastography (SWE) to assess testicular stiffness changes during the Valsalva maneuver in adolescents and young adults with varicocele, to compare these changes according to clinical severity, and to evaluate the role of SWE in the diagnosis of varicocele. METHODS: This study included patients undergoing testicular ultrasonography for the diagnosis of varicocele or for post-varicocelectomy follow-up between June 2016 and February 2017. Fifty-four testicles of 27 consecutive patients (mean age, 15.9 years) were classified by clinical grade (grade 0-3). Using SWE, mean testicular stiffness (Emean) was measured at rest and during the Valsalva maneuver. The correlations between multiple ultrasonographic parameters (volume asymmetry, Emean at rest, and absolute and percentage changes in Emean during the Valsalva maneuver) and clinical grade were assessed using the Spearman correlation test. RESULTS: The Emean at rest was similar across clinical grades. During the Valsalva maneuver, increased testicular stiffness was frequently observed in patients with grade 2 or 3 varicocele but rarely observed in those with grade 0 or 1 varicocele. The changes in Emean were positively correlated with the clinical grade (all P<0.001), whereas the Emean at rest and volume asymmetry were not (all P>0.05). CONCLUSION: A transient, reversible increase in testicular stiffness during the Valsalva maneuver was observed in adolescents with high-grade varicocele, and the degree of stiffness change was correlated with the clinical grade. Stiffness change identified using SWE during the Valsalva maneuver is a potential surrogate indicator of venous congestion.

Posterior Lung Herniation in Pulmonary Agenesis and Aplasia: Chest Radiograph and Cross-Sectional Imaging Correlation.

OBJECTIVE: To describe the anatomic locations and imaging features of posterior lung herniation in unilateral pulmonary agenesis and aplasia, focusing on radiograph-CT/MRI correlation. MATERIALS AND METHODS: A total of 10 patients (seven with pulmonary agenesis and three with pulmonary aplasia, male: female = 1:9, mean age 7.3 years, age range from 1 month to 20 years) were included. Chest radiographs (n = 9), CT (n = 9), and MRI (n = 1) were reviewed to assess the type of lung underdevelopment, presence of anterior and posterior lung herniation, bronchus origin, supplying artery, and draining vein of the herniated lung. RESULTS: Pulmonary agenesis/aplasia more commonly affected the left lung (n = 7) than the right lung (n = 3). Anterior lung herniation was observed in nine of the 10 patients. Posterior lung herniation was observed in seven patients with left pulmonary agenesis/aplasia. Two patients showed posterior lung herniation crossing the midline but not beyond the aorta, and five patients showed the posteriorly herniated right lower lobe crossing the midline to extend into the left hemithorax farther beyond the descending thoracic aorta through the space between the esophagus and the aorta. This anatomical configuration resulted in a characteristic radiographic finding of a radiolucent area with a convex lateral border and a vertical medial border in the left lower lung zone, revealing a tongue-like projection on CT and MRI. CONCLUSION: Posterior lung herniation occurs in unilateral left lung agenesis/aplasia. Approximately 70% of the cases of posterior lung herniation reveal a unique radiolucent tongue-like projection in the left lower lung zone on imaging studies, which is caused by the extension of the posteriorly herniated right lung farther beyond the descending aorta.

Establishment of Local Diagnostic Reference Levels of Pediatric Abdominopelvic and Chest CT Examinations Based on the Body Weight and Size in Korea.

OBJECTIVE: The purposes of this study were to analyze the radiation doses for pediatric abdominopelvic and chest CT examinations from university hospitals in Korea and to establish the local diagnostic reference levels (DRLs) based on the body weight and size. MATERIALS AND METHODS: At seven university hospitals in Korea, 2494 CT examinations of patients aged 15 years or younger (1625 abdominopelvic and 869 chest CT examinations) between January and December 2017 were analyzed in this study. CT scans were transferred to commercial automated dose management software for the analysis after being de-identified. DRLs were calculated after grouping the patients according to the body weight and effective diameter. DRLs were set at the 75th percentile of the distribution of each institution's typical values. RESULTS: For body weights of 5, 15, 30, 50, and 80 kg, DRLs (volume CT dose index [CTDIvol]) were 1.4, 2.2, 2.7, 4.0, and 4.7 mGy, respectively, for abdominopelvic CT and 1.2, 1.5, 2.3, 3.7, and 5.8 mGy, respectively, for chest CT. For effective diameters of < 13 cm, 14-16 cm, 17-20 cm, 21-24 cm, and > 24 cm, DRLs (size-specific dose estimates [SSDE]) were 4.1, 5.0, 5.7, 7.1, and 7.2 mGy, respectively, for abdominopelvic CT and 2.8, 4.6, 4.3, 5.3, and 7.5 mGy, respectively, for chest CT. SSDE was greater than CTDIvol in all age groups. Overall, the local DRL was lower than DRLs in previously conducted dose surveys and other countries. CONCLUSION: Our study set local DRLs in pediatric abdominopelvic and chest CT examinations for the body weight and size. Further research involving more facilities and CT examinations is required to develop national DRLs and update the current DRLs.

Enlarged periventricular space and periventricular lesion extension on baseline brain MRI predicts poor neurological outcomes in cryptococcus meningoencephalitis.

In Cryptococcus neoformans meningoencephalitis, brain MRI findings might reflect the phathomechanism of disease progression that is fungal accumulation in the peri-venular space and consequent invasion into the parenchyma. This study analyzed serial brain MRI findings of 76 patients with cryptococcus meningoencephalitis in association with the disease progression and outcomes. MRI parameters included the enlarged periventricular space (ePVS) score (range 0-8), periventricular lesion extension, cryptococcoma, and hydrocephalus. Clinical outcomes at 2-week, 10-week, and 6-month were evaluated using modified Rankin scale (mRS). At 6 months, 15 (19.7%) patients died and 34 (44.1%) had poor neurological outcomes (mRS scores > 2). At baseline, an ePVS score of ≥ 5 (Odds-ratio [OR]: 94.173, 95% confidence-interval [95%CI]: 7.507-1181.295, P < .001), periventricular lesion extension (OR: 51.965, 95%CI: 2.592-1041.673, P = .010), and presence of encephalitis feature (OR: 44.487, 95%CI: 1.689-1172.082, P = .023) were associated with 6-month poor outcomes. Presence of two or more risk factors among encephalitis feature, ePVS score ≥ 5, and periventricular lesion extension at baseline, was associated with 6-month poor outcomes (area under the curve [AUC]: 0.978, P < .001) and mortality (AUC: 0.836, P < .001). Disease progression was associated with interval development of cryptococcoma and hydrocephalus. Brain MRI findings might be useful in predicting outcomes and monitoring the progression of cryptococcus meningoencephalitis.

Kikuchi Cervical Lymphadenitis in Children: Ultrasound Differentiation From Common Infectious Lymphadenitis.

OBJECTIVES: To investigate ultrasound (US) features of enlarged cervical lymph nodes (LNs) to differentiate between Kikuchi disease (KD) and other common types of infectious lymphadenitis in an East Asian pediatric patient population. METHODS: A total of 142 pediatric patients with KD and 45 patients with infectious lymphadenitis (suppurative lymphadenitis [n = 29], nontuberculous mycobacterial lymphadenitis [n = 9], and tuberculous lymphadenitis [n = 7]) were included. The clinical characteristics, laboratory results, and US features of LNs were reviewed. The area under the curve (AUC) from a receiver operating characteristic curve analysis was used as a diagnostic accuracy measure. RESULTS: A multiple clustered adjacent pattern, bilaterality, an even size, posterior neck involvement, no enlargement, an elongated-to-ovoid shape, homogeneous hypoechogenicity, a well-defined margin, presence of an echogenic fatty hilum, no intranodal gross necrosis, increased perinodal fat echogenicity, and no increased echogenicity of the adjacent sternocleidomastoid muscle were significant US features of the affected LNs to discriminate KD from infectious lymphadenitis (P < .05). Homogeneous hypoechogenicity in KD showed the highest AUC (0.930) as a single variable (95% confidence interval, 0.88-0.96). The AUCs were increased in 3 combination models with 2 US features: homogeneous echogenicity and 1 of 3 other US features (increased perinodal fat echogenicity, 0.935; number of affected LNs, 0.947; and LN shape, 0.949). CONCLUSIONS: Homogeneous hypoechogenicity of LNs was a significant US feature with the highest diagnostic accuracy in differentiating KD from common infectious lymphadenitis on a univariate analysis. In the combination model, US features of an elongated-to-ovoid shape and homogeneous hypoechogenicity showed the highest diagnostic accuracy.

Diagnostic Performance of a New Convolutional Neural Network Algorithm for Detecting Developmental Dysplasia of the Hip on Anteroposterior Radiographs.

OBJECTIVE: To evaluate the diagnostic performance of a deep learning algorithm for the automated detection of developmental dysplasia of the hip (DDH) on anteroposterior (AP) radiographs. MATERIALS AND METHODS: Of 2601 hip AP radiographs, 5076 cropped unilateral hip joint images were used to construct a dataset that was further divided into training (80%), validation (10%), or test sets (10%). Three radiologists were asked to label the hip images as normal or DDH. To investigate the diagnostic performance of the deep learning algorithm, we calculated the receiver operating characteristics (ROC), precision-recall curve (PRC) plots, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) and compared them with the performance of radiologists with different levels of experience. RESULTS: The area under the ROC plot generated by the deep learning algorithm and radiologists was 0.988 and 0.988-0.919, respectively. The area under the PRC plot generated by the deep learning algorithm and radiologists was 0.973 and 0.618-0.958, respectively. The sensitivity, specificity, PPV, and NPV of the proposed deep learning algorithm were 98.0, 98.1, 84.5, and 99.8%, respectively. There was no significant difference in the diagnosis of DDH by the algorithm and the radiologist with experience in pediatric radiology (p = 0.180). However, the proposed model showed higher sensitivity, specificity, and PPV, compared to the radiologist without experience in pediatric radiology (p < 0.001). CONCLUSION: The proposed deep learning algorithm provided an accurate diagnosis of DDH on hip radiographs, which was comparable to the diagnosis by an experienced radiologist.

Echocardiographic index E/e' in association with cerebral white matter hyperintensity progression.

Cerebral white-matter hyperintensities (WMHs) on MRI is associated with reduced compliance of the cerebral arterioles. We hypothesized that an echocardiography index for left ventricular (LV) diastolic function, E/e', might reflect the cerebral arteriolar compliance and evaluated the association between E/e' and long-term progression rate of the cerebral WMH volume. This retrospective study included individuals who were ≥ 50 years of age, with a preserved LV ejection fraction (≥ 50%) and neurological function status (modified Rankin scale score ≤1), and underwent initial and follow-up MRI evaluations within intervals of 34-45 months. Baseline clinical, laboratory, and echocardiography markers such as ejection fraction, LV mass index, and E/e' were obtained. WMH volume progression rate between the baseline and follow-up MRIs was designated as the outcome factor. 392 individuals (57.1% men; mean age: 66.7±8.4 years) were followed-up for 38.2±3.4 months. The mean WMH volume progression rate was 1.35±2.65 mL/year. The log-transformed value of WMH volume progression rate was linearly associated with the log-transformed E/e' (B coefficient = 0.365; 95% confidence interval [CI] 0.180-0.551; P = 0.001), along with the log-transformed values of baseline WMH volume (B = 0.142; 95% CI 0.106-0.179; P<0.001) and glomerular filtration rate (B = -0.182; 95% CI -0.321-0.044; P = 0.010). Additionally, a subgroup with an E/e' ≥15 exhibited a significantly higher WMH progression rate compared to the subgroups with lower E/e' values (P<0.001), especially in the lower quartiles (quartiles 1 and 2) of the baseline WMH volume. We concluded that echocardiographic marker E/e' is associated with the long-term progression rate of cerebral WMHs in population with preserved LV systolic function.

Cervical lymphadenopathy in children: a diagnostic tree analysis model based on ultrasonographic and clinical findings.

OBJECTIVES: To establish a diagnostic tree analysis (DTA) model based on ultrasonography (US) findings and clinical characteristics for differential diagnosis of common causes of cervical lymphadenopathy in children. METHODS: A total of 242 patients (131 boys, 111 girls; mean age, 11.2 ± 0.3 years; range, 1 month-18 years) with pathologically confirmed Kikuchi disease (n = 127), reactive hyperplasia (n = 64), lymphoma (n = 24), or suppurative lymphadenitis (n = 27) who underwent neck US were included. US images were retrospectively reviewed to assess lymph node (LN) characteristics, and clinical information was collected from patient records. DTA models were created using a classification and regression tree algorithm on the basis of US imaging and clinical findings. The patients were randomly divided into training (70%, 170/242) and validation (30%, 72/242) datasets to assess the diagnostic performance of the DTA models. RESULTS: In the DTA model based on all predictors, perinodal fat hyperechogenicity, LN echogenicity, and short diameter of the largest LN were significant predictors for differential diagnosis of cervical lymphadenopathy (overall accuracy, 85.3% and 83.3% in the training and validation datasets). In the model based on categorical parameters alone, perinodal fat hyperechogenicity, LN echogenicity, and loss of fatty hilum were significant predictors (overall accuracy, 84.7% and 86.1% in the training and validation datasets). CONCLUSIONS: Perinodal fat hyperechogenicity, heterogeneous echotexture, short diameter of the largest LN, and loss of fatty hilum were significant US findings in the DTA for differential diagnosis of cervical lymphadenopathy in children. KEY POINTS: • Diagnostic tree analysis model based on ultrasonography and clinical findings would be helpful in differential diagnosis of pediatric cervical lymphadenopathy. • Significant predictors were perinodal fat hyperechogenicity, heterogeneous echotexture, short diameter of the largest LN, and loss of fatty hilum.

Impact of Endothelial Shear Stress on the Bilateral Progression of Unilateral Moyamoya Disease.

Background and Purpose- In unilateral moyamoya disease, altered endothelial shear stress on the intact-side terminal internal carotid artery might trigger the progression to bilateral disease. We analyzed the endothelial shear stress parameters of the normally appearing terminal internal carotid artery in unilateral moyamoya disease and its association with the progression to bilateral disease. Methods- This retrospective cohort study included patients diagnosed with unilateral moyamoya disease by cerebral angiography and followed-up with regular magnetic resonance imaging/magnetic resonance angiography evaluations for >1 year. Endothelial shear stress parameters acquired were mean and maximum signal intensity gradients (SIG) and SIG SD at the vessel boundary in time-of-flight sequences in initial brain magnetic resonance imaging/magnetic resonance angiography. Contralateral disease progression defined as the detection of newly developed vessel steno-occlusion with an magnetic resonance angiography steno-occlusive stage of ≥2, in the previously intact side of the brain on follow-up magnetic resonance imaging/magnetic resonance angiography evaluation. Results- Among 146 patients (66 males [45.2%] and 80 females [54.8%]; 76 pediatric [52.1%]), contralateral disease progression was detected in 43 patients (29.5%) after a mean follow-up of 4.3±2.4 years. Multivariate analysis showed that SIG SD was significantly associated with this progression (odds ratio, 13.001 [95% CI, 1.764-95.794], P=0.012). In receiver operating characteristic curve analysis, SIG SD predicted the contralateral progression with area under the curve values of 0.803 (95% CI, 0.726-0.880, P<0.001). The regression model was reproduced in the external cohort of 31 patients. Conclusions- Increased spatial variability of the endothelial shear stress around the normally appearing terminal internal carotid artery, as measured by SIG SD in time-of-flight sequences, may predict the contralateral progression of unilateral moyamoya disease.

Diagnostic value of computed tomography combined with ultrasonography in detecting cervical recurrence in patients with thyroid cancer.

BACKGROUND: To determine the diagnostic role of CT added to ultrasound for the diagnosis of recurrent differentiated thyroid cancer (DTC) and to evaluate potential benefits for patients. METHODS: A total of 193 patients with recurrent DTC were retrospectively included. The diagnostic performances of ultrasound and combination of ultrasound and CT (ultrasound/CT) in detecting recurrence were compared. Benefits of CT were assessed based on the presence of any recurrence detected only with additional CT. RESULTS: In detecting cervical recurrence, ultrasound/CT showed higher sensitivity (P = .001) and lower specificity (P < .001) than ultrasound alone, overall resulting in higher area under the curve (P < .001). Seventy-nine patients (40.9%) benefited from additional CT in detecting recurrence. CONCLUSION: For reoperation of cervical recurrence in patients with DTC, addition of CT to ultrasound offers better surgical planning by enhancing detection of recurrent cancers that were overlooked with ultrasound alone.

Radiologic evaluation of pulmonary injury following carmustine- and cyclophosphamide-based preparative regimen for autologous peripheral blood stem cell transplantation in children.

BACKGROUND: Toxicity of carmustine and cyclophosphamide can cause pulmonary injury after hematopoietic stem cell transplantation. OBJECTIVE: To evaluate the radiologic findings of pulmonary injuries following carmustine- and cyclophosphamide-based preparative regimens in children. MATERIALS AND METHODS: From 2010 to 2014, 35 children received carmustine- and cyclophosphamide-based preparative regimens. Fourteen of 35 children presented with symptoms and radiologic abnormalities. Eight of 14 children had no evidence of infection, cardiogenic edema, or other explainable causes. We retrospectively analyzed their chest radiographs and CT scans for ground-glass opacity, consolidation, septal thickening and pleural effusion. RESULTS: Major chest radiographic findings were bilateral diffuse ground-glass opacity (n=8) and septal thickening (n=7). CT findings were multifocal patchy (n=4) or inhomogeneously diffuse (n=4) ground-glass opacity, multifocal consolidations (n=7) and septal thickening (n=7). All of these lesions at CT were bilateral, but showed lower lobe predominance in 88, 100, and 63%, respectively. There was no central/peripheral or anterior/posterior predilection. Six children had small pleural effusions, which were bilateral in five children. CONCLUSION: Bilateral ground-glass opacity with or without consolidation, septal thickening and pleural effusion were common radiologic findings in pulmonary injury following carmustine- and cyclophosphamide-based preparative regimens.

Effect of arm position, presence of medical devices, and off-centering during acquisition of scout image on automatic tube voltage selection and current modulation in pediatric chest CT.

PURPOSE: To evaluate the patients' morphologic factors affecting radiation dose in pediatric chest CT. MATERIALS AND METHODS: From November 2013 to May 2015, 315 pediatric chest CT scans were obtained using a CT scanner, and classified into 5 groups according to the patients' age. For each age group, the chest CT scans were divided into two subgroups. A cut-off value used was the 75th percentile of size-specific dose estimates (SSDE), age-specific diagnostic reference level (DRL): less than the 75th percentile of SSDE (Group A, n = 238) and greater than the 75th percentile of SSDE (Group B, n = 77). All CT scans were performed with the same protocol using automatic tube voltage selection and current modulation techniques. The morphologic factors of the patients including body mass index (BMI), arm angles, presence of medical devices in the scan field, and degree of off-centering within the CT gantry were compared between groups A and B. RESULTS: Group B showed narrower arm angles on scout and coronal reformatted images, higher frequency of the presence of devices and higher BMI than group A (P < 0.001, P < 0.001; P = 0.018, and P < 0.001, respectively). In multivariate analysis, narrower arm angles, the presence of devices on the scout images and higher BMI were independently associated with higher SSDE (P = 0.001, P = 0.037, and P < 0.001, respectively). CONCLUSIONS: During acquisition of the scout images, arms-down position and the presence of medical devices were associated with a high radiation dose above age-specific DRLs in pediatric chest CT, regardless of repositioning before the actual scanning. In addition, off-centering had no clinical impact on radiation dose in the routine practice.

Development of Carbon-Based Solid Acid Catalysts Using a Lipid-Extracted Alga, Dunaliella tertiolecta, for Esterification.

Novel carbon-based solid acid catalysts were synthesized through a sustainable route from lipid-extracted microalgal residue of Dunaliella tertiolecta, for biodiesel production. Two carbon-based solid acid catalysts were prepared by surface modification of bio-char with sulfuric acid (H2SO4) and sulfuryl chloride (SO2Cl2), respectively. The treated catalysts were characterized and their catalytic activities were evaluated by esterification of oleic acid. The esterification catalytic activity of the SO2Cl2-treated bio-char was higher (11.5 mmol Prod.∙h⁻¹âˆ™g Cat. ⁻¹) than that of commercial catalyst silica-supported Nafion SAC-13 (2.3 mmol Prod.∙h⁻¹âˆ™g Cat. ⁻¹) and H2SO4-treated bio-char (5.7 mmol Prod.∙h⁻¹âˆ™g Cat. ⁻¹). Reusability of the catalysts was examined. The catalytic activity of the SO2Cl2-modified catalyst was sustained from the second run after the initial activity dropped after the first run and kept the same activity until the fifth run. It was higher than that of first-used Nafion. These experimental results demonstrate that catalysts from lipid-extracted algae have great potential for the economic and environment-friendly production of biodiesel.