Comprehensive analyses with radiological and biological markers of breast cancer on contrast-enhanced chest CT: a single center experience using dual-layer spectral detector CT.

OBJECTIVES: To evaluate the predictive value of virtual monoenergetic images (VMIs) by assessing tumor conspicuity on dual-layer spectral detector CT (SDCT) and correlate tumor conspicuity on VMI with prognostic biomarkers in patients with breast cancer. METHODS: Sixty-four patients underwent arterial phase and 90-s delayed phase dual-layer SDCT. A retrospective tumor conspicuity analysis of 14 benign tumors and 65 breast cancers was performed using conventional images (CIs) and VMI at 40 keV (VMI40) on arterial and delayed phase scans (CIART, VMI40ART, CIDE, VMI40DE). Mean Hounsfield units (HU) of tumors were measured on VMI40ART and VMI40DE. A receiver operating characteristic (ROC) curve analysis was performed to compare diagnostic accuracy between image sets. Estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki67 levels were evaluated using histopathology. Correlations between VMI analyses and histological characteristics of cancers were analyzed. RESULTS: Cancers on VMI40 had a significantly higher conspicuity score and mean HU than benign tumors (p < 0.001). VMI40DE showed the highest conspicuity for cancers (mean, 3.79) and the greatest area under the ROC curve (0.817; 95% confidence interval 0.745-0.889). VMI40DE yielded significantly higher mean HU for cancers than VMI40ART (p < 0.001). The conspicuity score and mean HU on VMI40ART were significantly higher in cancers with ER negativity, PR negativity, and Ki67 positivity (p < 0.05). CONCLUSIONS: VMI40DE may be useful in the diagnosis of breast cancers due to higher tumor conspicuity and better enhancement than VMI40ART. VMI40ART may be beneficial for the prediction of poor breast cancer prognoses. KEY POINTS: • VMI40 improved conspicuity of breast cancer than CI. • VMI40DEyielded higher diagnostic performance of breast cancer than VMI40ART. • VMI40ARThas an additional benefit in terms of prognosis prediction in patients with breast cancers.

One-Minute Ultrafast Brain MRI With Full Basic Sequences: Can It Be a Promising Way Forward for Pediatric Neuroimaging?

OBJECTIVE. The long scan time of brain MRI is a major drawback that limits its clinical use for evaluating pediatric patients who are inherently prone to motion and frequently require sedatives. This study investigated the clinical feasibility of a 1-minute ultrafast brain MRI protocol in pediatric patients by assessing its image quality in comparison with that of routine brain MRI. MATERIALS AND METHODS. Twenty-three patients were enrolled who underwent 1-minute ultrafast MRI and routine brain MRI protocols including five essential sequences (T1-weighted imaging, T2-weighted imaging, DWI, FLAIR, and T2*-weighted imaging). Total scan time for the same image contrast levels was 1 minute 11 seconds for ultrafast MRI versus 9 minutes 51 seconds for routine brain MRI. Two readers independently reviewed all images from the two MRI protocols and graded the image quality on a 4-point Likert scale. The Wilcoxon signed rank test was used to compare the readers' ratings; interobserver agreement between the readers was also assessed. RESULTS. Although the mean scores of overall image quality and anatomic delineation in ultrafast brain MR images were significantly lower than those in routine brain MR images, ultrafast brain MRI showed sufficient overall image quality and anatomic delineation with more than 2 points on the 4-point scale. CONCLUSION. The 1-minute ultrafast brain MRI protocol showed at least sufficient image quality compared with routine brain MRI. Therefore, 1-minute ultrafast brain MRI can be a viable first-line neuroimaging study for pediatric patients because of its shorter scan time, absence of radiation hazard, and reduced sedation requirements.

Initial clinical experience of synthetic MRI as a routine neuroimaging protocol in daily practice: A single-center study.

BACKGROUND AND PURPOSE: We investigated the clinical feasibility of synthetic MRI with a 4-min single scan using a 48-channel head coil as a routine neuroimaging protocol in daily practice by assessing its diagnostic image quality. METHODS: We retrospectively reviewed the imaging data of 89 patients who underwent routine brain MRI using synthetic MRI acquisition between February 2017 and April 2017. Image quality assessments were performed by two independent readers on synthetic T1 fluid-attenuated inversion recovery (FLAIR), T2-weighted, T2 FLAIR, and phase-sensitive inversion recovery sequences acquired using multiple-dynamic multiple-echo imaging. Interobserver reliability between the two readers was assessed using kappa (κ) statistics. RESULTS: On a 4-point assessment scale, the overall image quality and anatomical delineation provided by synthetic brain MRI were found to be good with scores of more than 3 points for all sequences except for the T2 FLAIR sequence. The synthetic T2 FLAIR sequence provided sufficient image quality but showed more pronounced artifacts, especially the CSF pulsation artifact and linear hyperintensity along the brain surface. Interobserver agreement for evaluating image quality of all synthetic sequences was good to excellent (κ, 0.61-0.99; P < 0.001). CONCLUSION: Synthetic MRI can be acceptable as a routine clinical neuroimaging protocol with a short scan time. It can be helpful to design customized and flexible neuroimaging protocols for each institution.

Preoperative Prophylactic Balloon-Assisted Occlusion of the Internal Iliac Arteries in the Management of Placenta Increta/Percreta.

Background and Objectives: Preoperative prophylactic balloon-assisted occlusion (PBAO) of the internal iliac arteries minimizes blood loss and facilitates surgery performance, through reductions in the rate of uterine perfusion, which allow for better control in hysterectomy performance, with decreased rates of bleeding and surgical complications. We aimed to investigate the maternal and fetal outcomes associated with PBAO use in women with placenta increta or percreta. Material and Methods: The records of 42 consecutive patients with a diagnosis of placenta increta or percreta were retrospectively reviewed. Of 42 patients, 17 patients (40.5%) with placenta increta or percreta underwent cesarean delivery after prophylactic balloon catheter placement in the bilateral internal iliac artery (balloon group). The blood loss volume, transfusion volume, postoperative hemoglobin changes, rates of hysterectomy and hospitalization, and infant Apgar score in this group were compared to those of 25 similar women who underwent cesarean delivery without balloon placement (surgical group). Results: The mean intraoperative blood loss volume in the balloon group (2319 ± 1191 mL, range 1000-4500 mL) was significantly lower than that in the surgical group (4435 ± 1376 mL, range 1500-10,500 mL) (p = 0.037). The mean blood unit volume transfused in the balloon group (2060 ± 1154 mL, range 1200-8000 mL) was significantly lower than that in the surgical group (3840 ± 1464 mL, range 1800-15,200 mL) (p = 0.043). There was no significant difference in the postoperative hemoglobin change, hysterectomy rates, length of hospitalization, or infant Apgar score between the groups. Conclusion: PBAO of the internal iliac artery prior to cesarean delivery in patients with placenta increta or percreta is a safe and minimally invasive technique that reduces the rate of intraoperative blood loss and transfusion requirements.

Comparison of lung imaging using three-dimensional ultrashort echo time and zero echo time sequences: preliminary study.

OBJECTIVE: To determine the feasibility of using high-resolution volumetric zero echo time (ZTE) sequence in routine lung magnetic resonance imaging (MRI) and compare free breathing 3D ultrashort echo time (UTE) and ZTE lung MRI in terms of image quality and small-nodule detection. MATERIALS AND METHODS: Our Institutional Review Board approved this study. Twenty patients underwent both UTE and ZTE sequences during routine lung MR. UTE and ZTE images were compared in terms of subjective image quality and detection of lung parenchymal signal, intrapulmonary structures, and sub-centimeter nodules. Differences between the two sequences were compared through statistical analysis. RESULTS: Lung parenchyma showed significantly (p < 0.05) higher signal-to-noise ratio (SNR) in ZTE than in UTE. The SNR and contrast-to-noise ratio (CNR) of peripheral bronchus and small pulmonary arteries were significantly (all p < 0.05) higher in ZTE. Subjective image quality evaluated by two independent radiologists in terms of depicting normal structures and overall acceptability was superior in ZTE (p < 0.05). The diagnostic accuracy for sub-centimeter nodules was significantly higher for ZTE (reader 1: AUC, 0.972; p = 0.044; reader 2: AUC, 0.946; p = 0.045) than that for UTE (reader 1: AUC, 0.885; reader 2: AUC, 0.855). Mean scan time was 131 s (125-141 s) in ZTE and 467 s (453-508 s) in UTE. ZTE images were obtained with less acoustic noise. CONCLUSION: Implementing ZTE as an additional sequence in routine lung MR is feasible. ZTE can provide high-resolution pulmonary structural information with better SNR and CNR using shorter time than UTE. KEY POINTS: • Both UTE and ZTE techniques use very short TEs to capture signals from very short T2/T2* tissues. • ZTE is superior in capturing lung parenchymal signal than UTE. • ZTE provides high-resolution structural information with better SNR and CNR for normal intrapulmonary structures and small nodules using shorter scan time than UTE.

Cervical Lymph Nodes Detected by F-18 FDG PET/CT in Oncology Patients: Added Value of Subsequent Ultrasonography for Determining Nodal Metastasis.

Background and Objectives: To investigate the diagnostic performance of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and subsequent ultrasonography (US) for determining cervical nodal metastasis in oncology patients. Materials and Methods: Fifty-nine cervical lymph nodes (LNs) initially detected by PET/CT with subsequent neck US were included in this retrospective study. All LNs were subjected to US-guided fine-needle aspiration or core needle biopsy. The maximum standardized uptake value (SUVmax) and sonographic features were assessed. Results: Forty-three of 59 cervical LNs detected by PET/CT were malignant. PET/CT alone showed a highest diagnostic value for metastatic LNs with 81.4% sensitivity, 68.8% specificity, and 78% accuracy when SUVmax ≥5.8 was applied as an optimal cut-off value. Combined PET/CT and subsequent US diagnoses for determining nodal metastasis showed the following diagnostic performance: 81.4% sensitivity, 87.5% specificity, and 83.1% accuracy. There was a significant difference in the diagnostic performance between the two diagnostic imaging approaches (p = 0.006). Conclusions: Combined diagnosis using subsequent US showed a significantly higher diagnostic performance for determining nodal metastasis in the neck. Therefore, we believe that our proposed diagnostic strategy using subsequent US can be helpful in evaluating cervical LNs on PET/CT. Moreover, our results clarify the need for US-guided tissue sampling in oncology patients.

A Novel Non-Apoptotic Role of Procaspase-3 in the Regulation of Mitochondrial Biogenesis Activators.

The executioner caspase-3 has been proposed as a pharmacological intervention target to preserve degenerating dopaminergic (DA) neurons because apoptotic mechanisms involving caspase-3 contribute, at least in part, to the loss of DA neurons in patients and experimental models of Parkinson's disease (PD). Here, we determined that genetic intervention of caspase-3 was sufficient to prevent cell death against oxidative stress (OS), accompanied by unexpected severe mitochondrial dysfunction. Specifically, as we expected, caspase-3-deficient DA neuronal cells were very significantly resistant to OS-induced cell death, while the activation of the initiator caspase-9 by OS was preserved. Moreover, detailed phenotypic characterization of caspase-3-deficient DA cells revealed severe mitochondrial dysfunction, including an accumulation of damaged mitochondria with a characteristic swollen structure and broken cristae, reduced membrane potential, increased levels of reactive oxygen species (ROS), and deficits in mitochondrial oxidative phosphorylation (OXPHOS) enzymes. Of great interest, we found that mitochondrial biogenesis was dramatically decreased in caspase-3-deficient DA cells, whereas their capability of mitophagy was normal. In accordance with this observation, caspase-3 gene knock down (KD) resulted in dramatically decreased expression of the key transcriptional activators of mitochondrial biogenesis, such as Tfam and Nrf-1, implicating a non-apoptotic role of procaspase-3 in mitochondrial biogenesis. Therefore, a prolonged anti-apoptotic intervention targeting caspase-3 should be considered with caution due to the potential adverse effects in mitochondria dynamics resulting from a novel potential functional role of procaspase-3 in mitochondrial biogenesis via regulating the expression of mitochondrial biogenesis activators. J. Cell. Biochem. 119: 347-357, 2018. © 2017 Wiley Periodicals, Inc.

Unenhanced 320-row multidetector computed tomography of the brain in children: comparison of image quality and radiation dose among wide-volume, one-shot volume, and helical scan modes.

BACKGROUND: The 320-row multidetector computed tomography (CT) scanner has multiple scan modes, including volumetric modes. OBJECTIVE: To compare the image quality and radiation dose of 320-row CT in three acquisition modes - helical, one-shot volume, and wide-volume scan - at pediatric brain imaging. MATERIALS AND METHODS: Fifty-seven children underwent unenhanced brain CT using one of three scan modes (helical scan, n=21; one-shot volume scan, n=17; wide-volume scan, n=19). For qualitative analysis, two reviewers evaluated overall image quality and image noise using a 5-point grading system. For quantitative analysis, signal-to-noise ratio, image noise and posterior fossa artifact index were calculated. To measure the radiation dose, adjusted CT dose index per unit volume (CTDIadj) and dose length product (DLP) were compared. RESULTS: Qualitatively, the wide-volume scan showed significantly less image noise than the helical scan (P=0.009), and less streak artifact than the one-shot volume scan (P=0.001). The helical mode showed significantly lower signal-to-noise ratio, with a higher image noise level compared with the one-shot volume and wide-volume modes (all P<0.05). The CTDIadj and DLP were significantly lower in the one-shot volume and wide-volume modes compared with those in the helical scan mode (all P<0.05). CONCLUSION: For pediatric unenhanced brain CT, both the wide-volume and one-shot volume scans reduced radiation dose compared to the helical scan mode, while the wide-volume scan mode showed fewer streak artifacts in the skull vertex and posterior fossa than the one-shot volume scan.

Nitric oxide induction of Parkin translocation in PTEN-induced putative kinase 1 (PINK1) deficiency: functional role of neuronal nitric oxide synthase during mitophagy.

The failure to trigger mitophagy is implicated in the pathogenesis of familial Parkinson disease that is caused by PINK1 or Parkin mutations. According to the prevailing PINK1-Parkin signaling model, mitophagy is promoted by the mitochondrial translocation of Parkin, an essential PINK1-dependent step that occurs via a previously unknown mechanism. Here we determined that critical concentrations of NO was sufficient to induce the mitochondrial translocation of Parkin even in PINK1 deficiency, with apparent increased interaction of full-length PINK1 accumulated during mitophagy, with neuronal nitric oxide synthase (nNOS). Specifically, optimum levels of NO enabled PINK1-null dopaminergic neuronal cells to regain the mitochondrial translocation of Parkin, which appeared to be significantly suppressed by nNOS-null mutation. Moreover, nNOS-null mutation resulted in the same mitochondrial electron transport chain (ETC) enzyme deficits as PINK1-null mutation. The involvement of mitochondrial nNOS activation in mitophagy was further confirmed by the greatly increased interactions of full-length PINK1 with nNOS, accompanied by mitochondrial accumulation of phospho-nNOS (Ser(1412)) during mitophagy. Of great interest is that the L347P PINK1 mutant failed to bind to nNOS. The loss of nNOS phosphorylation and Parkin accumulation on PINK1-deficient mitochondria could be reversed in a PINK1-dependent manner. Finally, non-toxic levels of NO treatment aided in the recovery of PINK1-null dopaminergic neuronal cells from mitochondrial ETC enzyme deficits. In summary, we demonstrated the full-length PINK1-dependent recruitment of nNOS, its activation in the induction of Parkin translocation, and the feasibility of NO-based pharmacotherapy for defective mitophagy and ETC enzyme deficits in Parkinson disease.

Pulmonary Tuberculosis in Patients With Emphysema: Computed Tomography Findings.

OBJECTIVE: To evaluate the computed tomography (CT) findings and clinical characteristics of pulmonary tuberculosis (TB) in patients with emphysema, compared with those without emphysema. MATERIALS AND METHODS: Thirty-nine patients (M:F = 36:3; mean age, 64.8 years) who were diagnosed with chronic obstructive pulmonary disease and had emphysema in pretreatment chest CT scans were included in this study (emphysema group). Their clinical presentation, laboratory findings, and CT findings were compared with those of 57 pulmonary TB patients without chronic obstructive pulmonary disease and emphysema (M:F = 52:5; mean age, 64.3 years) (nonemphysema group). RESULTS: Fever was a more frequent clinical presentation and the C-reactive protein level was higher in the emphysema group. Among CT findings, consolidation and ground-glass opacity were seen more frequently in the emphysema group (82% and 69% vs 42% and 19%, respectively, P < 0.001). Consolidation was more often nonsegmental than lobular or segmental. Tree-in-bud appearance was less frequently noted in the emphysema group (36% vs 79%, P < 0.001). The location of main lesions (upper lung vs middle/lower lung) was not different between the 2 groups. CONCLUSIONS: Pulmonary TB in emphysema patients often shows bacterial pneumonia-like features, that is, presence of consolidation and ground-glass opacity and lack of bronchogenic spread on chest CT scans, combined with the presence of fever and a high C-reactive protein level. Sputum smear for acid-fast bacteria should be performed early in emphysema patients with pneumonia in TB-endemic areas.

Relationships between the effect of sunitinib and immature blood vessels in metastatic renal cell cancer.

INTRODUCTION: This study was conducted to investigate the relationships between the effect of sunitinib and immature microvessels which are not covered by pericytes. MATERIALS AND METHODS: This study involved 29 patients with clear-cell renal cell carcinoma (RCC) who took sunitinib after radical nephrectomy or biopsy due to metastatic RCC. Associations among clinicopathological factors, responses to sunitinib, and patient survival were reviewed. CD31 was used to stain endothelial cells, and anti-α-smooth muscle actin was used to stain pericytes. Immature vessels were defined as vessels that were positive only for CD31 staining. A high pericyte coverage was defined as a rate of pericyte coverage above 40%. RESULTS: Partial responses, disease stabilization, and disease progression constituted 51.7, 10.4, and 37.9% of cases, respectively. Nine cases had a low pericyte coverage (31.0%). In the high-pericyte-coverage group, the number of metastatic sites was smaller (p=0.003). The overall response rate to sunitinib was greater in the high-pericyte-coverage group than in the low-pericyte-coverage group (p=0.027). The median overall survival and the median progression-free survival were not significantly different between the high- and low-pericyte-coverage groups. CONCLUSION: In the high-pericyte-coverage group, the overall response rates to sunitinib were higher, and the numbers of metastatic sites were smaller.

Tnfaip8 l1/Oxi-ß binds to FBXW5, increasing autophagy through activation of TSC2 in a Parkinson's disease model.

Abnormal autophagy may contribute to neurodegeneration in Parkinson's disease (PD). However, it is largely unknown how autophagy is dysregulated by oxidative stress (OS), one of major pathogenic causes of PD. We recently discovered the potential autophagy regulator gene family including Tnfaip8/Oxi-α, which is a mammalian target of rapamycin (mTOR) activator down-regulated by OS in dopaminergic neurons (J. Neurochem., 112, 2010, 366). Here, we demonstrate that the OS-induced Tnfaip8 l1/Oxi-ß could increase autophagy by a unique mechanism that increases the stability of tuberous sclerosis complex 2 (TSC2), a critical negative regulator of mTOR. Tnfaip8 l1/Oxi-ß and Tnfaip8/Oxi-α are the novel regulators of mTOR acting in opposition in dopaminergic (DA) neurons. Specifically, 6-hydroxydopamine (6-OHDA) treatment up-regulated Tnfaip8 l1/Oxi-ß in DA neurons, thus inducing autophagy, while knockdown of Tnfaip8 l1/Oxi-ß prevented significantly activation of autophagic markers by 6-OHDA. FBXW5 was identified as a novel binding protein for Tnfaip8 l1/Oxi-ß. FBXW5 is a TSC2 binding receptor within CUL4 E3 ligase complex, and it promotes proteasomal degradation of TSC2. Thus, Tnfaip8 l1/Oxi-ß competes with TSC2 to bind FBXW5, increasing TSC2 stability by preventing its ubiquitination. Our data show that the OS-induced Tnfaip8 l1/Oxi-ß stabilizes TSC2 protein, decreases mTOR phosphorylation, and enhances autophagy. Therefore, altered regulation of Tnfaip8 l1/Oxi-ß may contribute significantly to dysregulated autophagy observed in dopaminergic neurons under pathogenic OS condition. Dysfunctional autophagy is frequently observed in post-mortem brains of patients and animal models of Parkinson's disease. In dopaminergic neurons of the 6-hydroxydopamine (6-OHDA) model, oxidative stress induces Tnfaip8 l1/Oxi-ß, which results in increased autophagy by its exclusive binding with FBXW5 to stabilize TSC2. Thus, altered regulation of Tnfaip8 l1/Oxi-ß may contribute to dysregulated autophagy in dopaminergic neurons under pathogenic oxidative stress, implicating both Oxi-ß and FBXW5 as potential intervention targets for dysfunctional autophagy in dopaminergic neurons under oxidative stress.

Tnfaip8l1/Oxi-ß binds to FBXW5, increasing autophagy through activation of TSC2 in a Parkinson's disease model.

Abnormal autophagy may contribute to neurodegeneration in Parkinson's disease (PD). However, it is largely unknown how autophagy is dysregulated by oxidative stress (OS), one of major pathogenic causes of PD. We recently discovered the potential autophagy regulator gene family including Tnfaip8/Oxi-α, which is an mTOR activator downregulated by OS in dopaminergic neurons (Choi et al., 2010). Here we demonstrate that the OS-induced Tnfaip8l1/Oxi-ß could increase autophagy by a unique mechanism that increases the stability of TSC2, a critical negative regulator of mTOR. Tnfaip8l1/Oxi-ß and Tnfaip8/Oxi-α are the novel regulators of mTOR acting in opposition in DA neurons. Specifically, 6-hydroxydopamine (6-OHDA) treatment upregulated Tnfaip8l1/Oxi-ß in DA neurons, thus inducing autophagy, while knockdown of Tnfaip8l1/Oxi-ß prevented significantly activation of autophagic markers by 6-OHDA. FBXW5 was identified as a novel binding protein for Tnfaip8l1/Oxi-ß. FBXW5 is a TSC2 binding receptor within CUL4 E3 ligase complex, and it promotes proteasomal degradation of TSC2. Thus, Tnfaip8l1/Oxi-ß competes with TSC2 to bind FBXW5, increasing TSC2 stability by preventing its ubiquitination. Our data show that the OS-induced Tnfaip8l1/Oxi-ß stabilizes TSC2 protein, decreases mTOR phosphorylation and enhances autophagy. Therefore, altered regulation of Tnfaip8l1/Oxi-ß may contribute significantly to dysregulated autophagy observed in dopaminergic neurons under pathogenic OS condition. This article is protected by copyright. All rights reserved.

Electron microscopic analysis of necrotic bone and failed implant surface in a patient with medication-related osteonecrosis of the jaw.

BACKGROUND: Bisphosphonates (BP), a commonly used medication for various bone diseases, have been known to have severe complications such as bisphosphonate-related osteonecrosis of the jaw (BRONJ). Failure of dental implants has also been found in patients with medication-related osteonecrosis of the jaw (MRONJ). In this study, we analyzed the necrotic bone tissues and the surface of the failed implants removed from the jaw in patients treated with BPs and antiresorptive agents. RESULTS: Chronic inflammatory cells with collagen and fibrous tissues and bone sequestrum were shown at 5.0 × , 10.0 × , 20.0 × , and 40.0 × magnified histologic sections in the bone and fibrotic scar tissues removed from patients with MRONJ due to osteonecrosis. Hardened bone tissues with microcracked bony resorbed lacunae were observed in SEM. Unlike the previously published comparative data where immune cells, such as dendritic cells, were found in the failed implant surface, these immune cells were not identified in the BRONJ-related peri-implantitis tissues through the TEM investigations. Furthermore, EDS revealed that in addition to the main titanium element, gold, carbon, oxygen, calcium, phosphorus, silicon, and sulfur elements were found. CONCLUSION: Hardened bone tissues with microcracked bony resorbed lacunae were observed in the SEM findings, which were considered as the main characteristic of the osteonecrosis of the jaw. Immune cells, such as dendritic cells were not identified in the TEM. EDS showed that in addition to the main titanium element, gold, carbon, oxygen, calcium, phosphorus, and silicon elements were found. Furthermore, it was revealed that sulfur was found, which was considered to be one of the complicated causes of implant failure in patients with BRONJ.

Contrast-enhanced voiding ultrasonography to detect intrarenal reflux in children: comparison with 99mTc-DMSA renal scans.

PURPOSE: This study evaluated the diagnostic performance of contrast-enhanced voiding ultrasonography (CeVUS) for detecting intrarenal reflux (IRR) and the correlation between CeVUS-detected IRR sites and photon defect sites in acute 99mTc-dimercaptosuccinic acid (DMSA) renal scans in pediatric patients. METHODS: Fifty-four kidneys from 27 patients (20 males and seven females; mean age, 5.6±4.1 months) who underwent CeVUS and acute DMSA renal scans for recurrent urinary tract infection (UTIs) or pyelonephritis were included. Pediatric experts compared the results of CeVUS with acute DMSA renal scans. RESULTS: Thirteen renal units (13/54, 24.1%) in 10 patients (nine males and one female; mean age, 6.3±3.7 months; age range, 0 to 13 months) showed vesicoureteral reflux and eight renal units (8/54, 14.8%) demonstrated IRR on CeVUS. Ten renal units in eight patients (six males and two females; mean age, 6.9±1.4 months; age range, 2 to 13 months) showed 19 photon defects on acute DMSA renal scans. Fifty-two renal units (96.3%) showed concordant results, and two renal units (3.7%) showed discordant results between CeVUS and acute DMSA renal scans. IRR accounted for 15/19 (78.9%) photon defects in eight renal units of seven patients using CeVUS. In a per-renal-unit analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CeVUS were 80%, 100%, 100%, 95.7%, and 96.3%, respectively. CONCLUSION: CeVUS showed good performance in detecting IRR, and the IRR sites detected by CeVUS closely correlated with photon defect sites in acute DMSA scans. CeVUS may play an important role in managing patients with recurrent UTIs or pyelonephritis with reduced radiation exposure.

Deep Learning-Assisted Diagnosis of Pediatric Skull Fractures on Plain Radiographs.

OBJECTIVE: To develop and evaluate a deep learning-based artificial intelligence (AI) model for detecting skull fractures on plain radiographs in children. MATERIALS AND METHODS: This retrospective multi-center study consisted of a development dataset acquired from two hospitals (n = 149 and 264) and an external test set (n = 95) from a third hospital. Datasets included children with head trauma who underwent both skull radiography and cranial computed tomography (CT). The development dataset was split into training, tuning, and internal test sets in a ratio of 7:1:2. The reference standard for skull fracture was cranial CT. Two radiology residents, a pediatric radiologist, and two emergency physicians participated in a two-session observer study on an external test set with and without AI assistance. We obtained the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity along with their 95% confidence intervals (CIs). RESULTS: The AI model showed an AUROC of 0.922 (95% CI, 0.842-0.969) in the internal test set and 0.870 (95% CI, 0.785-0.930) in the external test set. The model had a sensitivity of 81.1% (95% CI, 64.8%-92.0%) and specificity of 91.3% (95% CI, 79.2%-97.6%) for the internal test set and 78.9% (95% CI, 54.4%-93.9%) and 88.2% (95% CI, 78.7%-94.4%), respectively, for the external test set. With the model's assistance, significant AUROC improvement was observed in radiology residents (pooled results) and emergency physicians (pooled results) with the difference from reading without AI assistance of 0.094 (95% CI, 0.020-0.168; p = 0.012) and 0.069 (95% CI, 0.002-0.136; p = 0.043), respectively, but not in the pediatric radiologist with the difference of 0.008 (95% CI, -0.074-0.090; p = 0.850). CONCLUSION: A deep learning-based AI model improved the performance of inexperienced radiologists and emergency physicians in diagnosing pediatric skull fractures on plain radiographs.

Feasibility study of ultra-low-dose dedicated maxillofacial computed tomography using filter-based spectral shaping in patients with craniofacial trauma: assessment of image quality and radiation dose.

BACKGROUND: In the setting of multiple trauma, radiation exposure is considered a relevant issue because patients may require repeated imaging to evaluate injuries in different body parts. Recently, spectral shaping of the X-ray beam has been shown to be beneficial in reducing radiation exposure. We investigated the clinical feasibility of a tin-filtered 100 kV protocol for the diagnostic use, compared to routine dedicated maxillofacial CT at 120 kVp in patients with craniofacial trauma; we assessed the image quality, radiation dose, and interobserver agreement. METHODS: We retrospectively evaluated 100 consecutive patients who underwent dedicated maxillofacial CT for craniofacial trauma. Fifty patients were examined with a tin-filtered 100 kV protocol performed using a third-generation dual source CT. The other 50 patients were examined with a standard protocol on a different scanner. Two readers independently evaluated image quality subjectively and objectively, and the interobserver agreement was also assessed. CT dose index volume (CTDIvol) and dose-length product (DLP) were recorded to compare radiation exposure. A quality-control phantom was also scanned to prospectively assess the impact of tin filtration. RESULTS: All CT scans showed diagnostic image quality for evaluating craniofacial fractures. The tin-filtered 100 kV protocol showed sufficient-to-good image quality for diagnostic use; however, overall image quality and anatomic delineation from the tin-filtered 100 kV protocol were significantly lower than from the standard protocol. Interobserver agreement was moderate to almost perfect (k=0.56-0.85). Image noises in the air, eye globe, and retrobulbar fat were comparable between the two protocols (P>0.05), whereas both signal-to-noise ratio and contrast-to-noise ratio in the eye globe and retrobulbar fat showed a significant difference (P<0.05). The tin-filtered 100 kV protocol showed a significant reduction in radiation dose compared to the standard protocol: CTDIvol, 3.33 vs. 30.5 mGy (P<0.001); and DLP, 70.70 vs. 669.43 mGy*cm (P<0.001). The phantom study also demonstrated a lower radiation dose for the tin-filter 100 kV protocol compared to the standard protocol. CONCLUSIONS: Dedicated maxillofacial CT using spectral shaping with tin filtration can allow a significant reduction in radiation dose while maintaining sufficient diagnostic image quality, when compared to the standard protocol.

Generating synthetic contrast enhancement from non-contrast chest computed tomography using a generative adversarial network.

This study aimed to evaluate a deep learning model for generating synthetic contrast-enhanced CT (sCECT) from non-contrast chest CT (NCCT). A deep learning model was applied to generate sCECT from NCCT. We collected three separate data sets, the development set (n = 25) for model training and tuning, test set 1 (n = 25) for technical evaluation, and test set 2 (n = 12) for clinical utility evaluation. In test set 1, image similarity metrics were calculated. In test set 2, the lesion contrast-to-noise ratio of the mediastinal lymph nodes was measured, and an observer study was conducted to compare lesion conspicuity. Comparisons were performed using the paired t-test or Wilcoxon signed-rank test. In test set 1, sCECT showed a lower mean absolute error (41.72 vs 48.74; P < .001), higher peak signal-to-noise ratio (17.44 vs 15.97; P < .001), higher multiscale structural similarity index measurement (0.84 vs 0.81; P < .001), and lower learned perceptual image patch similarity metric (0.14 vs 0.15; P < .001) than NCCT. In test set 2, the contrast-to-noise ratio of the mediastinal lymph nodes was higher in the sCECT group than in the NCCT group (6.15 ± 5.18 vs 0.74 ± 0.69; P < .001). The observer study showed for all reviewers higher lesion conspicuity in NCCT with sCECT than in NCCT alone (P ≤ .001). Synthetic CECT generated from NCCT improves the depiction of mediastinal lymph nodes.

A novel mTOR activating protein protects dopamine neurons against oxidative stress by repressing autophagy related cell death.

Our previous microarray analysis identified a neuroprotective protein Oxi-alpha, that was down-regulated during oxidative stress (OS)-induced cell death in dopamine neurons [Neurochem. Res. (2004) vol. 29, pp. 1223]. Here we find that the phylogenetically conserved Oxi-alpha protects against OS by a novel mechanism: activation of the mammalian target of rapamycin (mTOR) kinase and subsequent repression of autophagic vacuole accumulation and cell death. To the best of our knowledge, Oxi-alpha is the first molecule discovered in dopamine neurons, which activates mTOR kinase. Indeed, the down-regulation of Oxi-alpha by OS suppresses the activation of mTOR kinase. The pathogenic effect of down-regulated Oxi-alpha was confirmed by gene-specific knockdown experiment, which resulted in not only the repression of mTOR kinase and the subsequent phosphorylation of p70 S6 kinase and 4E-BP1, but also enhanced susceptibility to OS. In accordance with these observations, treatment with rapamycin, an mTOR inhibitor and autophagy inducer, potentiated OS-induced cell death, while similar treatment with an autophagy inhibitor, 3-methyladenine protected the dopamine cells. Our findings present evidence for the presence of a novel class of molecule involved in autophagic cell death triggered by OS in dopamine neurons.

Pneumothorax after CT-guided transthoracic lung biopsy: A comparison between immediate and delayed occurrence.

BACKGROUND: In CT-guided transthoracic lung biopsy (CTLB), pneumothorax can occur as a late complication (delayed pneumothorax). The incidence, risk factors, and clinical significance of delayed pneumothorax are not well known. OBJECTIVES: To compare the risk factors for immediate and delayed pneumothorax after CTLB and to know their clinical significance. METHODS: Images and medical records of 536 consecutive patients who underwent CTLB were reviewed. All biopsies were performed as inpatient procedures. Follow-up chest radiographs were obtained at least twice at 4 h after procedure and before discharge. Risk factors for immediate and delayed pneumothorax were assessed based on patient-, lesion-, and procedure-related variables. Rates of chest tube insertion were also compared. RESULTS: Pneumothorax developed in 161 patients (30.0%) including 135 (25.2%) immediate and 26 (4.9%) delayed cases. Lesion size was an independent risk factor for both immediate and delayed pneumothorax (OR = 0.813; CI = 0.717-0.922 and OR = 0.610; CI = 0.441-0.844, respectively). While emphysema, lower lobe location, and long intrapulmonary biopsy track were risk factors (OR = 1.981; CI = 1.172-3.344, OR = 3.505; CI = 2.718-5.650, and OR = 1.330; CI = 1.132-1.563, respectively) for immediate pneumothorax, upper lobe location and increased number of pleural punctures were independent risk factors (OR = 5.756; CI = 1.634-20.274 and OR = 3.738; CI = 1.860-7.511, respectively) for delayed pneumothorax. The rate of chest tube insertion was significantly (p < 0.001) higher in delayed pneumothorax. CONCLUSION: Pneumothorax tends to occur immediately after CTLB in patients with emphysema, lower lobe lesion, and long intrapulmonary biopsy track. Further attention and warnings are needed for those with multiple punctures of small lesions involving upper lobes due to the possibility of delayed development of pneumothorax and higher requirement for chest tube drainage.