Low-dose CT angiography of the lower extremities: a comparison study of image quality and radiation dose

AIM

To investigate the image quality and radiation dose of ultralow-dose (ULD) and low-dose (LD) lower-extremity computed tomography (CT) angiography (LE-CTA) using the advanced modelled iterative reconstruction (ADMIRE) algorithm to detect peripheral arterial disease (PAD) in comparison with standard-dose (SD) CT.

MATERIALS AND METHODS

One hundred and seven consecutive patients were examined using LE-CTA at 70 kVp and a dual-source scanner to achieve three image sets using 30% (ULD), 70% (LD), and 100% (SD) tube loads. Qualitative analysis was conducted by examining the three image sets for overall quality. The image quality of arterial segments was analysed by two independent readers. In addition, the CT dose index (CTDI_vol) was measured in the three image sets.

RESULTS

The mean overall quality scores were 3.4±0.6 for ULD CT, 3.9±0.3 for LD CT, and 3.9±0.2 for SD CT. Both readers scored the arterial segments as 2-4 (adequate-excellent) in the three image sets. In addition, 89.4% (93/104) and 54.8% (57/104) segments of PAD with calcified plaques were scored 4 between SD and LD CT and between SD and ULD CT, respectively, and 45.2% (47/104) segments had a lower score by one point in ULD CT compared with SD CT. The mean CTDI_vol was 4.1±1.1 mGy for SD CT, 2.9±0.8 mGy for LD CT, and 1.2±0.3 mGy for ULD CT.

CONCLUSIONS

LD/ULD CT at 70 kVp using ADMIRE reconstruction enables a reduction in the radiation dose while enabling adequate evaluation or follow-up of PAD based on LE-CTA.

Development and Validation of a Deep Learning-Based Automatic Brain Segmentation and Classification Algorithm for Alzheimer Disease Using 3D T1-Weighted Volumetric Images

BACKGROUND AND PURPOSE

Limited evidence has suggested that a deep learning automatic brain segmentation and classification method, based on T1-weighted brain MR images, can predict Alzheimer disease. Our aim was to develop and validate a deep learning-based automatic brain segmentation and classification algorithm for the diagnosis of Alzheimer disease using 3D T1-weighted brain MR images.

MATERIALS AND METHODS

A deep learning-based algorithm was developed using a dataset of T1-weighted brain MR images in consecutive patients with Alzheimer disease and mild cognitive impairment. We developed a 2-step algorithm using a convolutional neural network to perform brain parcellation followed by 3 classifier techniques including XGBoost for disease prediction. All classification experiments were performed using 5-fold cross-validation. The diagnostic performance of the XGBoost method was compared with logistic regression and a linear Support Vector Machine by calculating their areas under the curve for differentiating Alzheimer disease from mild cognitive impairment and mild cognitive impairment from healthy controls.

RESULTS

In a total of 4 datasets, 1099, 212, 711, and 705 eligible patients were included. Compared with the linear Support Vector Machine and logistic regression, XGBoost significantly improved the prediction of Alzheimer disease (P < .001). In terms of differentiating Alzheimer disease from mild cognitive impairment, the 3 algorithms resulted in areas under the curve of 0.758-0.825. XGBoost had a sensitivity of 68% and a specificity of 70%. In terms of differentiating mild cognitive impairment from the healthy control group, the 3 algorithms resulted in areas under the curve of 0.668-0.870. XGBoost had a sensitivity of 79% and a specificity of 80%.

CONCLUSIONS

The deep learning-based automatic brain segmentation and classification algorithm allowed an accurate diagnosis of Alzheimer disease using T1-weighted brain MR images. The widespread availability of T1-weighted brain MR imaging suggests that this algorithm is a promising and widely applicable method for predicting Alzheimer disease.

Clinical features and predictors of masked uncontrolled hypertension: from Korean ambulatory blood pressure monitoring (Korabp) registry

Background

Clinical characteristics of patients with masked uncontrolled hypertension (MUCH) are poorly defined, and few studies have reported on clinical predictors of MUCH. We investigated demographic, lifestyle, clinical and blood pressure (BP) characteristics in patients with MUCH and proposed a prediction model for MUCH.

Method

We analyzed 2044 subjects taking antihypertensive medication enrolled in the Korean Ambulatory Blood Pressure Monitoring (Kor-ABP) registry, who were categorized into controlled hypertension (n=481, normal office BP, normal 24-hour ABP), pseudo-uncontrolled hypertension (n=131, high office BP, normal 24-hour ABP), MUCH (n=380, normal office BP, high 24-hour ABP), and sustained uncontrolled hypertension (n=1,052; high office BP and high 24-hour ABP).

Result

The prevalence of MUCH increased with office systolic BP (SBP) and diastolic BP (DBP), whereas it was not associated with the numbers of antihypertensive drugs. But in patients with a high office SBP (≥130 mmHg), the prevalence of MUCH increased with decreasing numbers of antihypertensive drugs (interaction p=0.008; Figure 1A). Multiple logistic regression analysis identified high office SBPs and DBPs, prior stroke, dyslipidemia and single anti-hypertensive agent use as independent predictors of MUCH (Table 1). A prediction model using these predictors showed a high diagnostic accuracy (C-index 0.833) and a goodness of fit for the presence of MUCH (Figure 1B).

Conclusion

MUCH is associated with the borderline increase in office BP and the underuse of anti-hypertensive drugs as well as dyslipidemia and prior stroke, which underscores the importance of achieving the optimal BP control level in the high risk patients. The proposed model would accurately predict MUCH in patients with controlled office BP.

Figure 1

Funding Acknowledgement

Type of funding source: None

Empagliflozin treatment does not affect the hypertensive response to Ang II administration to rats but decreases oxidative stress in the arterial wall, and endothelial and cardiac dysfunction

Background

Selective sodium-glucose cotransporter 2 (SGLT2) inhibitors have shown cardiovascular protection in type 2 diabetes patients with established cardiovascular disease independently of glycemic control. Angiotensin II (Ang II) and H2O2 have been shown to be strong inducers of the expression of SGLT2 and 1 in endothelial cells promoting oxidative stress and endothelial dysfunction.

Purpose

This study examined the cardiovascular protective effect of empagliflozin (empa) in a normoglycemic experimental model of hypertension in the rat.

Methods

Male Wistar rats received empa (30 mg/kg/day) provided in the diet for 5 weeks. After 1 week, rats underwent sham surgery (sham rats) or surgery with implantation of an osmotic mini-pump infusing Ang II (0.4 mg/kg/d) for 4 weeks. Systolic blood pressure (SBP) was assessed by sphygmomanometry, the cardiac function using echocardiography, the expression level of target proteins by immunofluorescence staining, and the level of oxidative stress using dihydroethidium staining.

Results

Angiotensin II administration increased systolic blood pressure from about 130 to 180 mmHg, which was not affected by the empa treatment. The 4-week Ang II treatment did not significantly affect the systolic cardiac function (cardiac output, left ventricle ejection fraction) but impaired the diastolic function as indicated by a reduced E' and IVRT values, and an increased E/E' value. The Ang II treatment increased significantly the heart and right ventricle weight whereas the left ventricle + septum weight was slightly but not significantly increased. No such functional and structural changes were observed in the Ang II + empa treatment group. An increased immunofluorescence eNOS signal in the endothelium, and a higher level of ROS throughout the aorta wall were observed in the Ang II-treated group, both of which were significantly reduced in the empa + Ang II-treated group. In the Ang II-treated group, the high level of oxidative stress in the aorta was significantly reduced by the AT1 receptor antagonist losartan, the NADPH oxidase inhibitor VAS-2871, the eNOS inhibitor NG-nitro-L-arginine and also to a greater extent by the selective SGLT2 inhibitor empa compared to the dual SGLT1/2 inhibitor sotagliflozin.

Conclusion(s)

The present findings indicate that although the empa treatment did not affect the hypertensive response of rats to Ang II, the SGLT2 inhibitor prevented the deleterious impact of Ang II on the diastolic cardiac function and remodeling, and the upregulation of eNOS expression and oxidative stress in the aorta wall. Thus, these findings highlight the protective potential of empa on the cardiovascular system in a normoglycemic hypertensive experimental model.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Boehringer Ingelheim Pharma GmbH & Co KG (Biberach an der Riss, Germany)

Differences in the clinical characteristics and long-term outcome of peripartum tako-tsubo cardiomyopathy and peripartum cardiomyopathy

Background

Some peripartum-associated cardiomyopathy patients present similarly to those of tako-tsubo cardiomyopathy (TCM), little is known about the clinical course of peripartum TCM.

Purpose

To know clinicial characteristics and outcomes of peripartum TCM, in comparison with peripartum cardiomyopathy (PPCM)

Methods and results

Of 31 pregnancy-associated cardiomyopathy patients in a tertiary hospital, 10 cases of peripartum TCM and 21 cases of PPCM were found. Maternal near-missed death was significantly more common in the peripartum TCM group than in the PPCM group (100.0% vs. 76.2%, p=0.030). Complete recovery was observed with all peripartum TCM cases, while 23.8% of the PPCM cases had residual left ventricle (LV) dysfunction. LV ejection fraction greater than 30% on the initial echocardiogram independently predicted early echocardiographic recovery of left ventricular systolic function (odds ratio 331.33, 95% confidence interval 3.87–28402.60, p=0.011). There was no difference between the two groups in terms of the rate of adverse clinical events at 3 years of follow-up (PPCM group: 26.3% [5/19] vs. TCM group: 33.3% [3/9], p=0.750).

Conclusions

One-third of pregnancy-associated cardiomyopathy patients had peripartum TCM. With contemporary supportive care, both PPCM and peripartum TCM patients had a low mortality rate and excellent long-term outcomes.

Kaplan-Meier survival curves for death,

Funding Acknowledgement

Type of funding source: None

Associations between Household Water Fluoridation Status and Plain Tap or Bottled Water Consumption

INTRODUCTION

The benefits of community water fluoridation for preventing dental caries are attenuated if people do not consume tap water.

OBJECTIVES

We examined associations between household water fluoride content and consuming plain tap or bottled water among US youth.

METHODS

We used National Health and Nutrition Examination Survey data for 2013 to 2016 for 5,193 youth aged 2 to 19 y. Fluoride content in youth's household tap water samples was measured electrometrically with ion-specific electrodes and designated low (<0.6 mg/L) or about optimal (0.6 to 1.2 mg/L). Plain tap and bottled water consumption was obtained from one 24-h dietary recall. We used binomial regression models to estimate adjusted prevalence ratios (APRs) and 95% CIs for consuming plain tap water (including tap only or both tap and bottled) and consuming only bottled water as related to household water fluoride content (low or about optimal) and sociodemographic characteristics.

RESULTS

On a given day, 52.6% of youth consumed plain tap water (43.8% exclusively and 8.8% both tap and bottled) and 28%, only bottled water. Neither tap water (APR, 0.96; 95% CI, 0.84 to 1.10) nor only bottled water (APR, 1.03; 95% CI, 0.86 to 1.22) consumption was associated with household water fluoride content. Non-Hispanic Black youth and Hispanic youth were about 30% relatively less likely to consume tap water and 60% to 80% relatively more likely to consume only bottled water than non-Hispanic Whites. Low income, low parental education, and no past-year dental visit were associated with not consuming tap water.

CONCLUSION

Half of youth consumed plain tap water on a given day. Consuming plain tap water was not associated with community water fluoridation status. This study is the first to find that up to 50% of the population served by fluoridated water may not receive its full caries-preventive benefits due to not consuming plain tap water.

KNOWLEDGE TRANSFER STATEMENT

Half of US youth consumed plain tap water on a given day. Consuming plain tap water was not associated with community water fluoridation status. This finding suggests that up to 50% of the population served by fluoridated water systems may not receive its full caries-preventive benefits due to not consuming plain tap water. Our findings add support for the need to identify and address barriers to tap water consumption and promote health benefits of fluoridation.

Bronchovascular bundle thickening on CT as a predictor of survival and brain metastasis in patients with stage IA peripheral small cell lung cancer

AIM

To determine if bronchovascular bundle (BVB) thickening on pretreatment computed tomography (CT) images helps predict survival in patients with peripheral small cell lung cancer (pSCLC) ≤3 cm.

MATERIALS AND METHODS

The pretreatment CT examinations of 79 histopathologically proven pSCLC ≤3 cm (TNM stage I, 21; II, 13; III, 22; IV, 23) were reviewed retrospectively. The CT characteristics of the nodule and associated findings, including BVB thickening, were evaluated. Progression-free survival (PFS), overall survival (OS), and brain metastasis-free survival were compared with the presence of BVB thickening using Kaplan-Meier and Cox regression analysis.

RESULTS

Among the 79 patients, 34 (43%) had BVB thickening. BVB thickening was prevalent in patients with mediastinal lymph node metastasis (50.9% versus 22.7%; p=0.024) and distant metastasis (60.9% versus 35.7%; p=0.049). Out of the 21 patients with TNM stage IA disease, the 16 patients (76.2%) without BVB thickening showed better PFS, OS, and brain metastasis-free survival (mean, 1,762 versus 483 days; p=0.019: 2,243 versus 1,328 days; p=0.038: 2,274 versus 1,287 days; p=0.038, respectively). Multivariate Cox regression analysis showed that the absence of BVB thickening (hazard ratio [HR], 7.806; 95% CI, 1.241-49.091; p=0.029) and surgery (HR, 0.075; 95% CI, 0.008-0.746; p=0.027) were independent and useful prognostic factors for PFS.

CONCLUSIONS

BVB thickening was found more frequently in patients with advanced-stage pSCLC ≤3 cm, and the PFS was more favourable in patients without BVB thickening, with a similar tendency to that of OS and brain metastasis-free survival, in stage IA pSCLC.

Treatment of Molar Incisor Malformation and the short term follow-up: Case reports

BACKGROUND

Molar Incisor Malformation (MIM) or Molar Root Incisor malformation (MRIM) is a recently discovered root malformation with constricted pulp and abnormally located furcation presented in permanent first molars and sometimes incisors.

CASE REPORT

Two cases that feature MIM are presented with the description of the characteristic tooth form, clinical/radiographic examination, medical history, the supposed aetiology, treatment procedure and results at the 2-year follow-up. Conservative endodontic treatment was performed in both cases, furcation perforation and canal perforation were filled with MTA (Mineral Trioxide Aggregate), and a good prognosis was observed after 2 years of follow-up. Furthermore, recommended treatment options are discussed to provide a more appropriate treatment for the patients.

CONCLUSION

Patients with MIM need to be treated at the right time to avoid severe infection and other problems. Early diagnosis with appropriate treatment is more likely to lead to a more favourable prognosis.

Potential anti-ageing effect of chondroitin sulphate through skin regeneration

OBJECTIVE

Skin ageing is inevitably exposed through its typical features such as wrinkles and sagging. Therefore, skin anti-ageing is a major issue in cosmetic research to prevent and improve ageing symptoms using effective ingredients. Chondroitin sulphate (CS), a type of glycosaminoglycan, is an important structural component of the extracellular matrix (ECM) and is involved in various biological processes, such as cell proliferation, differentiation and migration. Here, we aimed to investigate the effects of CS on skin regeneration and examine its efficacy as a potential safe and effective skin anti-ageing ingredient.

METHODS

We investigated the effects of CS on cell proliferation in normal human keratinocytes and fibroblasts. Then, cell migration, ECM synthesis and related signalling pathways were examined in fibroblasts through gene and protein expression analysis. Finally, the effect on skin wound healing and regeneration was validated using a full-thickness skin wound model and an aged skin model.

RESULTS

Chondroitin sulphate treatment increased the proliferation of keratinocytes and fibroblasts. It also stimulated the migration and synthesis of ECM components of fibroblasts. Further analysis revealed that CS induced the expression of type I procollagen by activating the extracellular signal-regulated kinase pathway. Using a full-thickness skin wound model and an aged skin model, we confirmed that CS treatment promoted skin wound healing and regeneration.

CONCLUSION

Together, our results indicated that CS has the potential to facilitate skin regeneration, implying that CS could be clinically applied to improve skin ageing.

Surface Point Cloud Ultrasound with Transcranial Doppler: Coregistration of Surface Point Cloud Ultrasound with Magnetic Resonance Angiography for Improved Reproducibility, Visualization, and Navigation in Transcranial Doppler Ultrasound

Transcranial Doppler (TCD) ultrasound is a standard tool used in the setting of recent sub-arachnoid hemorrhage (SAH). By tracking velocity in the circle-of-Willis vessels, vasospasm can be detected as interval velocity increase. For this disease process, repeated TCD velocity measurements over many days is the basis for its usefulness. However, a key limitation to TCD is its user dependence, which is itself largely due to the fact that exact information about probe positioning is lost between subsequent scans. Surface point cloud ultrasound (SPC-US) was recently introduced as a general approach combining ultrasound and three-dimensional surface imaging of patient + probe. In the present proof-of-principle demonstration, we have applied SPC-US to TCD and co-registered the skin surface with that from MRA images to provide a roadmap of the vasculature in 3D space for better speed, accuracy, reproducibility, and potential semi-automation of TCD. Collating the acronyms, we call the combined approach SPC-US-TCD. TCD of the M1 was obtained while three-dimensional photographic images were obtained with the Structure Sensor camera. MRA imaging was also obtained. SPC-US-TCD and corresponding MRA 3D reconstruction images were co-registered in MeshMixer using the skin surfaces for alignment. A cylinder the width of the TCD probe was placed over the fused images and aligned with the direction and orientation of the TCD probe to demonstrate the acoustic beam. In the fused images, the acoustic beam intersects the right M1 segment of the middle cerebral artery (MCA). The angle of insonation is well demonstrated and measurable in various planes. Distance measurements made in Blender localized the TCD probe position based on three skin surface landmarks, and tabulated orientation based on three angles along the corresponding directions. SPC-US-TCD provides valuable information that is otherwise not present in TCD studies. By co-registering SPC-US-TCD data with that from cross sectional vessel imaging, precise probe location relative to external skin surface landmarks as well as 3D vessel location relative to TCD probe placement offers the potential to provide a roadmap that improves exam reproducibility, speed of acquisition, and accuracy. The goal of future work is to demonstrate this improvement statistically by application to multiple patients and scans.

Exploring stories of learning and professional development: interactions between GP personal tutors and medical students

BACKGROUND

The demanding environment at medical school results in some students being prone to a high risk of mental health issues. GMC recommendations include positioning personal tutors for pastoral support and to act as academic role models. Tutors who are clinicians, such as GPs, could help students develop their academic and professional narratives. Our study explores interactions between GP tutors and students and evaluates how personal tutoring can support the ways in which students respond to the medical school culture and its demands.

METHOD

Six pairs of GP tutors and medical students had three personal tutor meetings over 9 months. Twelve meetings were recorded. A dialogical narrative analytical approach was used to assess how students' problems and reflective processes were negotiated with tutors. Three themes were formed to consolidate findings.

RESULTS

Tutors' affirmations helped students develop an alternative narrative to perfectionism focusing on 'doing well' and self-care. Reflection on students' perceptions of a medical career were prompted by tutors who encouraged students to keep an open-minded and enthusiastic outlook. Active participation from students sometimes required tutors to relinquish hierarchical power and share personal experiences.

CONCLUSION

GP tutors can help reframe student narratives of perfectionism and professionalism by expressing their vulnerabilities and working collaboratively. With clear guidance, there is potential for personal tutors working as GPs, to benefit students in the long run both academically and professionally. However, this should go hand in hand with a transformation of medical school culture to prevent sole focus on building student resilience.

Improving treatments for psychotic disorders: beyond cognitive behaviour therapy for psychosis

More effective treatments for people with psychotic disorders are urgently required. Here, we make three suggestions for progress: 1. Targeting the disorders' core phenomenological features ('phenomenological phenotype'), 2. Addressing social disconnection, isolation and loneliness, and 3. Leveraging 'hot' cognitions and using symptom capture approaches that combine psychotherapy with advances in technology and neuroscience.

Probing Few-Body Nuclear Dynamics via ^{3}H and ^{3}He (e,e^{'}p)pn Cross-Section Measurements

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9  (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500  MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350  MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250  MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500  MeV/c.