Development and Evaluation of Deep Learning-Based Automatic Segmentation Model for Skull Zero TE MRI in Children

Purpose@#To develop and evaluate a deep learning technique to automatically segment bone structures in zero echo time (ZTE) for skull magnetic resonance imaging (MRI) in children. @*Materials and Methods@#From January to December 2021, 38 bone ZTE MRIs from infants and children (age range, 1–31 months) were collected for model development.Mask images were generated by manually segmenting the craniofacial bone using a commercial segmentation program. Among them, 35 ZTE series were used to train the three-dimensional (3D)-nnUnet deep learning model and the remaining three series were used for model validation. A temporally different dataset of 19 ZTE bone MRIs obtained in May 2022 from infants and children (age range, 3–168 months) was used to determine the model’s performance. Dice similarity coefficient was calculated for each test case.From 3D volume rendering images, segmentation accuracy, overall image quality, and visibility of cranial sutures were subjectively evaluated on a 5-point scale and compared with ground truth data from manual segmentation. Reasons for segmentation failure were analyzed using axially segmented ZTE images. @*Results@#For the test set, the mean Dice similarity coefficient was 0.985 ± 0.019. The segmentation accuracy was lower than the ground truth without showing a statistically significant difference between the two (3.39 ± 1.11 vs. 3.73 ± 0.77, p = 0.055). The overall image quality and suture visibility showed no significant difference (3.34 ± 0.75 vs.3.42 ± 0.69, p = 0.317; 3.55 ± 0.97 vs. 3.60 ± 0.95, p = 0.157). Common reasons for low segmentation accuracy were well-pneumatized sinuses, metal artifacts, skin at the vertex level, and bones too thin. @*Conclusion@#The deep learning-based automatic segmentation technique of bone ZTE MRIs showed comparable segmentation performance to manual segmentation. Using the deep learning-based segmentation results, acceptable 3D-volume rendering images of craniofacial bones were generated.

Ultrasound findings of subpial hemorrhage in neonates

Purpose@#Subpial hemorrhage (SPH) is a subtype of intracranial hemorrhage characterized by damage to the adjacent brain parenchyma. The aim of this study was to describe the sonographic features of SPH in neonates. @*Methods@#The cranial ultrasound (US) findings of neonates with SPH confirmed by brain magnetic resonance imaging (MRI) were analyzed retrospectively. Initial and follow-up US and MRI scans were reviewed by two pediatric radiologists who were blinded to both clinical history and outcomes. The US features were compared with the MRI findings. @*Results@#Sixteen patients were included (median gestational age, 38 weeks; range, 26 to 40 weeks; 69% term). SPH was detected most often in the temporal lobe (63%), and multiple SPHs were found in seven of 16 neonates, based on MRI. Acute SPH with an underlying venous infarct (UVI) was detected on US in 15 of 16 patients: small or large fan-shaped hyperechoic lesions (n=7 and 4, respectively) and gyriform hyperechoic lesions (n=4). The sonographic yin-yang sign was observed in three of the four large fan-shaped SPH cases. The accompanying findings on US were intraventricular hemorrhage (four out of six MRI-confirmed cases), and concurrent periventricular venous infarcts (five out of nine MRI-confirmed cases). In five patients, subpial cysts were observed on follow-up US or MRI (n=4 and n=4, respectively). @*Conclusion@#Acute SPH with UVI can appear as a peripheral fan-shaped or gyriform hyperechoic lesion on cranial US. SPH can be detected and suspected based on the US features of SPH with the accompanying findings.

Optimal Kiloelectron Volt for Noise-Optimized Virtual Monoenergetic Images of Dual-Energy Pediatric Abdominopelvic Computed Tomography: Preliminary Results

OBJECTIVE: To compare quantitative and qualitative image quality parameters in pediatric abdominopelvic dual-energy CT (DECT) using noise-optimized virtual monoenergetic image (VMI) and conventional VMI at different kiloelectron volt (keV) levels. MATERIALS AND METHODS: Thirty-six consecutive abdominopelvic DECT scans were retrospectively included. Noise-optimized VMI and conventional VMI were reconstructed at seven energy levels, from 40 keV to 100 keV at 10 keV intervals. The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of the liver, pancreas, and aorta were objectively measured and compared. Image quality was evaluated subjectively regarding image noise, image blurring of solid organ, bowel image quality and severity of beam-hardening artifacts. Optimal monoenergetic levels in keV for both algorithms were determined based on overall image quality score. RESULTS: The maximal CNR and SNR values for all investigated organs were observed at 40 keV in noise-optimized VMI (CNR and SNR of liver, pancreas, aorta in order [CNR; 20.93, 17.34, 46.75: SNR; 37.39, 33.80, 63.21]), at 60–70 keV and at 70 keV in conventional VMI (CNR; 8.12, 5.67, 15.97: SNR; 19.57, 16.66, 26.65). In qualitative image analysis, noise-optimized VMI and conventional VMI showed the best overall image quality scores at 60 keV and at 70 keV, respectively. Noise-optimized VMI at 60 keV showed superior CNRs, SNRs, and overall image quality scores compared to conventional VMI at 70 keV (p < 0.001). CONCLUSION: Optimal energy levels for noise-optimized VMI and conventional VMI were 60 keV and at 70 keV, respectively. Noise-optimized VMI shows superior CNRs, SNRs and subjective image quality over conventional VMI, at the optimal energy level.

Influence of glass-based dental ceramic type and thickness with identical shade on the light transmittance and the degree of conversion of resin cement / 国际口腔科学杂志·英文版

The purpose of this study was to assess the influence of the types and thicknesses of glass ceramic plates on light transmittance and compare the degrees of conversion (DC) of resin cement under the ceramic materials. Three ceramic plates with thicknesses of 0.5, 1.0, 2.0, and 4.0 mm were fabricated from each of five commercial ceramic blocks in shade A2: high-translucency and low-translucency IPS Empress CAD (Emp_HT and Emp_LT); high-translucency and low-translucency IPS e.max CAD (Emx_HT and Emx_LT); and Vita Mark II (Vita). The translucency parameter was obtained using a colorimeter. The light transmittance rate was measured using a photodetector attached to an optical power meter. The DC of a resin cement (Variolink N) underneath the ceramic plates was examined by Fourier transform infrared spectroscopy. The translucency parameter, light transmittance rate, and DC showed significant differences by ceramic type and thickness (P  0.05). Both type and thickness of the glass ceramics significantly influenced the light transmittance and DC of the light-cured resin cement beneath the ceramic of the same shade.

Idiopathic Cervicosyringomyelia in 2 year-old Boy / 대한소아신경학회지

Syringomyelia is a disorder in which a cavity has formed within the spinal cord. Idiopathic syringomyelia is not associated with identifiable causes such as Chari type 1 malformation, spinal cord tumor, vascular malformation, tethered cord, arachnoiditis, hydrocephalus, or previous spinal surgery. The main neurologic symptoms of idiopathic syringomyelia are toe-walking, constipation, incontinence, abnormal reflexes, and lower extremity weakness. Patients may present with various symptoms such as scoliosis, cutaneous markers, pain in the lower extremities or back, or may be asymptomatic. Herein, we report a young child with idiopathic syringomyelia presenting with subtle neck pain. A 23-month-old boy visited the neurologic clinic after 3 months of right occipital area neck pain. He had no history of trauma or central nervous system infection, and neurologic examination results were normal except for right posterior neck hyperesthesia. Brain and spinal magnetic resonance imaging showed an ovoid intramedullary cystic lesion (9.7×5.0×4.7 mm) at C6/7 of the spinal cord. There was no evidence of Chiari malformation or other lesions that can be primary pathologies of syringomyelia. Electromyogram/nerve conduction velocity results were normal. The subject was diagnosed as idiopathic syringomyelia. His symptoms and neurologic/radiologic indications showed no change at a 1-year follow-up. Idiopathic syringomyelia symptoms are varied and may be overlooked by physicians. Pediatricians may consider syringomyelia if patients complain about persistent sensory abnormality. All patients who present with syringomyelia should undergo detailed neuroimaging of the entire neuraxis to elucidate the proximate cause of the lesion.

Fatty Degeneration and Atrophy of Rotator Cuffs: Comparison of Immediate Postoperative MRI with Preoperative MRI

PURPOSE: The purpose of this study was to compare the grade of fatty degeneration and atrophy of rotator cuffs on immediate postoperative MRI to those on preoperative MRI in patients with rotator cuff tears. MATERIALS AND METHODS: Seventy patients were included in this study, who received arthroscopic rotator-cuff repair and underwent both preoperative magnetic resonance imaging (MRI) and immediate postoperative MRI in our institution. Fatty degeneration of rotator cuffs and the atrophy of supraspinatus muscles were evaluated with T1 oblique sagittal images in the Y-shaped view. Fatty degeneration was evaluated using a Goutallier classification system, and the atrophy of supraspinatus muscles was evaluated using a modified tangent sign and a visual occupation ratio. RESULTS: From 70 patients, a total of 100 tendons were repaired: 18, 69, and 13 tendons were treated for subscapularis, supraspinatus, and infraspinatus, respectively. The Goutallier grades (P = 0.012), modified tangent signs (P = 0.000), and visual occupation ratios (P = 0.000) of supraspinatus muscles were significantly decreased in immediate postoperative MRIs when compared to preoperative MRIs. In immediate postoperative MRIs, the Goutallier grades of supraspinatus muscles were decreased by one grade in 18.8% (n = 13) of the patients, and the atrophy of supraspinatus muscles was improved by one grade in 26.1% (n = 18) for modified tangent signs and 21.7% (n = 15) for visual occupation ratios. However, fatty infiltration by the Goutallier grades of subscapularis (P = 1.000) and infraspinatus (P = 0.157) muscles were not significantly changed after arthroscopic surgery. CONCLUSION: Immediate postoperative MRIs showed a significant improvement of fatty degeneration and muscle atrophy in supraspinatus muscles when compared to preoperative MRIs.

Brain ultrasonographic findings of late-onset circulatory dysfunction due to adrenal insufficiency in preterm infants

PURPOSE: The aim of this study was to characterize the brain ultrasonographic findings of late-onset circulatory dysfunction (LCD) due to adrenal insufficiency (AI) in preterm infants. METHODS: Among the 257 preterm infants born at <33 weeks of gestation between December 2009 and February 2014 at our institution, 35 preterm infants were diagnosed with AI. Brain ultrasonographic findings were retrospectively analyzed before and after LCD in 14 preterm infants, after exclusion of the other 21 infants with AI due to the following causes: death (n=2), early AI (n=5), sepsis (n=1), and patent ductus arteriosus (n=13). RESULTS: Fourteen of 257 infants (5.4%) were diagnosed with LCD due to AI. The age at LCD was a median of 18.5 days (range, 9 to 32 days). The last ultrasonographic findings before LCD occurred showed grade 1 periventricular echogenicity (PVE) in all 14 patients and germinal matrix hemorrhage (GMH) with focal cystic change in one patient. Ultrasonographic findings after LCD demonstrated no significant change in grade 1 PVE and no new lesions in eight (57%), grade 1 PVE with newly appearing GMH in three (21%), and increased PVE in three (21%) infants. Five infants (36%) showed new development (n=4) or increased size (n=1) of GMH. Two of three infants (14%) with increased PVE developed cystic periventricular leukomalacia (PVL) and rapid progression to macrocystic encephalomalacia. CONCLUSION: LCD due to AI may be associated with the late development of GMH, increased PVE after LCD, and cystic PVL with rapid progression to macrocystic encephalomalacia.

Inhibition of matrix metalloproteinases expression in human dental pulp cells by all-trans retinoic acid / 国际口腔科学杂志·英文版

All-trans retinoic acid (ATRA) inhibits matrix metalloproteinase (MMP)-2 and MMP-9 in synovial fibroblasts, skin fibroblasts, bronchoalveolar lavage cells and cancer cells, but activates MMP-9 in neuroblast and leukemia cells. Very little is known regarding whether ATRA can activate or inhibit MMPs in human dental pulp cells (HDPCs). The purpose of this study was to determine the effects of ATRA on the production and secretion of MMP-2 and -9 in HDPCs. The productions and messenger RNA (mRNA) expressions of MMP-2 and -9 were accessed by gelatin zymography and real-time polymerase chain reaction (PCR), respectively. ATRA was found to decrease MMP-2 level in a dose-dependent manner. Significant reduction in MMP-2 mRNA expression was also observed in HDPCs treated with 25 µmol⋅L(-1) ATRA. However, HDPCs treated with ATRA had no effect on the pattern of MMP-9 produced or secreted in either cell extracts or conditioned medium fractions. Taken together, ATRA had an inhibitory effect on MMP-2 expression in HDPCs, which suggests that ATRA could be a candidate as a medicament which could control the inflammation of pulp tissue in vital pulp therapy and regenerative endodontics.

Bronchopulmonary Dysplasia: New High Resolution Computed Tomography Scoring System and Correlation between the High Resolution Computed Tomography Score and Clinical Severity

OBJECTIVE: To develop an high resolution computed tomography (HRCT) scoring system for the assessment of bronchopulmonary dysplasia (BPD) and determine its usefulness as compared with the chest radiographic score. MATERIALS AND METHODS: Forty-two very low-birth-weight preterm infants with BPD (25 male, 17 female) were prospectively evaluated with HRCT performed at the mean age of 39.1-week postmenstrual age. Clinical severity of BPD was categorized as mild, moderate or severe. The HRCT score (0-36) of each patient was the sum of the number of bronchopulmonary segments with 1) hyperaeration and 2) parenchymal lesions (linear lesions, segmental atelectasis, consolidation and architectural distortion), respectively. We compared the HRCT scores with the chest radiographic scores (the Toce system) in terms of correlation with clinical severity. RESULTS: The HRCT score had good interobserver (r = 0.969, p < 0.001) and intraobserver (r = 0.986, p < 0.001) reproducibility. The HRCT score showed better correlation (r = 0.646, p < 0.001) with the clinical severity of BPD than the chest radiographic score (r = 0.410, p = 0.007). The hyperaeration score showed better correlation (r = 0.738, p < 0.001) with the clinical severity of BPD than the parenchymal score (r = 0.523, p < 0.001). CONCLUSION: We have developed a new HRCT scoring system for BPD based on the quantitative evaluation of pulmonary abnormalities of BPD consisting of the hyperaeration score and the parenchymal score. The HRCT score shows better correlation with the clinical severity of BPD than the radiographic score.

Balloon Dilatation for Corrosive Esophageal Strictures in Children: Radiologic and Clinical Outcomes

OBJECTIVE: We retrospectively evaluated the effectiveness of the esophageal balloon dilatation (EBD) in children with a corrosive esophageal stricture. MATERIALS AND METHODS: The study subjects included 14 patients (M:F = 8:6, age range: 17-85 months) who underwent an EBD due to a corrosive esophageal stricture. The causative agents for the condition were glacial acetic acid (n = 9) and lye (n = 5). RESULTS: A total of 52 EBD sessions were performed in 14 patients (range 1-8 sessions). During the mean 15-month follow-up period (range 1-79 months), 12 patients (86%) underwent additional EBD due to recurrent esophageal stricture. Dysphagia improved after each EBD session and oral feeding was possible between EBD sessions. Long-term success (defined as dysphagia relief for at least 12 months after the last EBD) was achieved in two patients (14%). Temporary success of EBD (defined as dysphagia relief for at least one month after the EBD session) was achieved in 17 out of 52 sessions (33%). A submucosal tear of the esophagus was observed in two (4%) sessions of EBD. CONCLUSION: Only a limited number of children with corrosive esophageal strictures were considered cured by EBD. However, the outcome of repeated EBD was sufficient to allow the children to eat per os prior to surgical management.

Magnetic Resonance Imaging Findings of Portal Biliopathy

PURPOSE: We wanted to evaluate the MR imaging findings of portal biliopathy. MATERIALS AND METHODS: We retrospectively reviewed the MR imaging of twelve patients having biliary abnormalities and portal cavernoma. Two radiologists working in consensus analyzed the presence of extrahepatic portal vein obstruction, cavernous transformation, portosystemic collaterals and bile ducts abnormalities that included irregular contour, stricture, ductal dilatation, wall thickening and enhancement of the ductal wall. RESULTS: Extrahepatic portal vein obstruction was replaced by cavernous transformations in all patients. The cavernous transformations depicted on the MR scans were paracholedochal veins in 12 patients and epicholedochal veins in 6 patients. Three different types of biliary abnormalities were present: 1) the pseudocholangiocarcinoma type (3 patients) that resembled extrahepatic cholangiocarcinoma, 2) the varicoid type (6 patients) that was mainly distinguished by the multiple smooth extrinsic impressions along the common bile duct and 3) the mixed type (3 patients). The highly specific findings for the pseudocholangiocarcinoma type disease were thickening and delayed enhancement of the biliary ductal wall. CONCLUSION: The MR findings of portal biliopathy include cavernous transformation of the portal vein and morphological alterations of the biliary tracts such as irregular contour, biliary stricture with proximal ductal dilatation and thickening of the ductal wall with delayed enhancement. Recognition of these MR findings should facilitate the accurate diagnosis of portal biliopathy and prevent the misinterpretation or inappropriate management of this disease as malignancy or sclerosing chloangitis.