Predicting FDG-PET Images From Multi-Contrast MRI Using Deep Learning in Patients With Brain Neoplasms

BACKGROUND

18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is valuable for determining presence of viable tumor, but is limited by geographical restrictions, radiation exposure, and high cost.

PURPOSE

To generate diagnostic-quality PET equivalent imaging for patients with brain neoplasms by deep learning with multi-contrast MRI.

STUDY TYPE

Retrospective.

SUBJECTS

Patients (59 studies from 51 subjects; age 56 ± 13 years; 29 males) who underwent 18 F-FDG PET and MRI for determining recurrent brain tumor.

FIELD STRENGTH/SEQUENCE

3T; 3D GRE T1, 3D GRE T1c, 3D FSE T2-FLAIR, and 3D FSE ASL, 18 F-FDG PET imaging.

ASSESSMENT

Convolutional neural networks were trained using four MRIs as inputs and acquired FDG PET images as output. The agreement between the acquired and synthesized PET was evaluated by quality metrics and Bland-Altman plots for standardized uptake value ratio. Three physicians scored image quality on a 5-point scale, with score ≥3 as high-quality. They assessed the lesions on a 5-point scale, which was binarized to analyze diagnostic consistency of the synthesized PET compared to the acquired PET.

STATISTICAL TESTS

The agreement in ratings between the acquired and synthesized PET were tested with Gwet's AC and exact Bowker test of symmetry. Agreement of the readers was assessed by Gwet's AC. P = 0.05 was used as the cutoff for statistical significance.

RESULTS

The synthesized PET visually resembled the acquired PET and showed significant improvement in quality metrics (+21.7% on PSNR, +22.2% on SSIM, -31.8% on RSME) compared with ASL. A total of 49.7% of the synthesized PET were considered as high-quality compared to 73.4% of the acquired PET which was statistically significant, but with distinct variability between readers. For the positive/negative lesion assessment, the synthesized PET had an accuracy of 87% but had a tendency to overcall.

CONCLUSION

The proposed deep learning model has the potential of synthesizing diagnostic quality FDG PET images without the use of radiotracers.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Early-Frame [18F]Florbetaben PET/MRI for Cerebral Blood Flow Quantification in Patients with Cognitive Impairment: Comparison to an [15O]Water Gold Standard

Cerebral blood flow (CBF) may be estimated from early-frame PET imaging of lipophilic tracers, such as amyloid agents, enabling measurement of this important biomarker in participants with dementia and memory decline. Although previous methods could map relative CBF, quantitative measurement in absolute units (mL/100 g/min) remained challenging and has not been evaluated against the gold standard method of [15O]water PET. The purpose of this study was to develop and validate a minimally invasive quantitative CBF imaging method combining early [18F]florbetaben (eFBB) with phase-contrast MRI using simultaneous PET/MRI. Methods: Twenty participants (11 men and 9 women; 8 cognitively normal, 9 with mild cognitive impairment, and 3 with dementia; 10 β-amyloid negative and 10 β-amyloid positive; 69 ± 9 y old) underwent [15O]water PET, phase-contract MRI, and eFBB imaging in a single session on a 3-T PET/MRI scanner. Quantitative CBF images were created from the first 2 min of brain activity after [18F]florbetaben injection combined with phase-contrast MRI measurement of total brain blood flow. These maps were compared with [15O]water CBF using concordance correlation (CC) and Bland-Altman statistics for gray matter, white matter, and individual regions derived from the automated anatomic labeling (AAL) atlas. Results: The 2 methods showed similar results in gray matter ([15O]water, 55.2 ± 14.7 mL/100 g/min; eFBB, 55.9 ± 14.2 mL/100 g/min; difference, 0.7 ± 2.4 mL/100 g/min; P = 0.2) and white matter ([15O]water, 21.4 ± 5.6 mL/100 g/min; eFBB, 21.2 ± 5.3 mL/100 g/min; difference, -0.2 ± 1.0 mL/100 g/min; P = 0.4). The intrasubject CC for AAL-derived regions was high (0.91 ± 0.04). Intersubject CC in different AAL-derived regions was similarly high, ranging from 0.86 for midfrontal regions to 0.98 for temporal regions. There were no significant differences in performance between the methods in the amyloid-positive and amyloid-negative groups as well as participants with different cognitive statuses. Conclusion: We conclude that eFBB PET/MRI can provide robust CBF measurements, highlighting the capability of simultaneous PET/MRI to provide measurements of both CBF and amyloid burden in a single imaging session in participants with memory disorders.

Generative Adversarial Network-Enhanced Ultra-Low-Dose [18F]-PI-2620 τ PET/MRI in Aging and Neurodegenerative Populations

BACKGROUND AND PURPOSE

With the utility of hybrid τ PET/MR imaging in the screening, diagnosis, and follow-up of individuals with neurodegenerative diseases, we investigated whether deep learning techniques can be used in enhancing ultra-low-dose [18F]-PI-2620 τ PET/MR images to produce diagnostic-quality images.

MATERIALS AND METHODS

Forty-four healthy aging participants and patients with neurodegenerative diseases were recruited for this study, and [18F]-PI-2620 τ PET/MR data were simultaneously acquired. A generative adversarial network was trained to enhance ultra-low-dose τ images, which were reconstructed from a random sampling of 1/20 (approximately 5% of original count level) of the original full-dose data. MR images were also used as additional input channels. Region-based analyses as well as a reader study were conducted to assess the image quality of the enhanced images compared with their full-dose counterparts.

RESULTS

The enhanced ultra-low-dose τ images showed apparent noise reduction compared with the ultra-low-dose images. The regional standard uptake value ratios showed that while, in general, there is an underestimation for both image types, especially in regions with higher uptake, when focusing on the healthy-but-amyloid-positive population (with relatively lower τ uptake), this bias was reduced in the enhanced ultra-low-dose images. The radiotracer uptake patterns in the enhanced images were read accurately compared with their full-dose counterparts.

CONCLUSIONS

The clinical readings of deep learning-enhanced ultra-low-dose τ PET images were consistent with those performed with full-dose imaging, suggesting the possibility of reducing the dose and enabling more frequent examinations for dementia monitoring.

Exposure to Metalworking Fluids and Cancer Incidence in the United Auto Workers-General Motors Cohort

In previous studies, investigators have reported increased risks of specific cancers associated with exposure to metalworking fluids (MWFs). In this report we broadly examine the incidence of 14 types of cancer, with a focus on digestive, respiratory, and hormonal cancers, in the United Auto Workers-General Motors (UAW-GM) cohort, a cohort of workers exposed to MWFs (1973-2015). The cohort included 39,132 workers followed for cancer incidence. Cox models yielded estimates of adjusted hazard ratios, with categorical variables for lagged cumulative exposure to 3 types of MWF (straight, soluble, and synthetic). We fitted penalized splines to examine the shape of the exposure-response relationships. There were 7,809 incident cancer cases of interest. Oil-based straight and soluble MWFs were each modestly associated with all cancers combined. Exposure-response patterns were consistent with prior reports from this cohort, and results for splined exposures generally reflected their categorically modeled counterparts. We found significantly increased incidence of stomach and kidney cancer with higher levels of straight MWF exposure and increased rectal and prostate cancer with increasing water-based synthetic MWF exposure. Only non-Hodgkin lymphoma and prostate cancer were associated with soluble MWF. All results for colon and lung cancers were null. Our results provide updated evidence for associations between MWF exposure and incidence of several types of cancer.

Assessment of motion and model bias on the detection of dopamine response to behavioral challenge

Compartmental modeling analysis of ¹¹C-raclopride (RAC) PET data can be used to measure the dopaminergic response to intra-scan behavioral tasks. Bias in estimates of binding potential (BP_ND) and its dynamic changes (ΔBP_ND) can arise both when head motion is present and when the compartmental model used for parameter estimation deviates from the underlying biology. The purpose of this study was to characterize the effects of motion and model bias within the context of a behavioral task challenge, examining the impacts of different mitigation strategies. Seventy healthy adults were administered bolus plus constant infusion RAC during a simultaneous PET/magnetic resonance (MR) scan with a reward task experiment. BP_ND and ΔBP_ND were estimated using an extension of the Multilinear Reference Tissue Model (E-MRTM2) and a new method (DE-MRTM2) was proposed to selectively discount the contribution of the initial uptake period. Motion was effectively corrected with a standard frame-based approach, which performed equivalently to a more complex reconstruction-based approach. DE-MRTM2 produced estimates of ΔBP_ND in putamen and nucleus accumbens that were significantly different from those estimated from E-MRTM2, while also decoupling ΔBP_ND values from first-pass k₂' estimation and removing skew in the spatial bias distribution of parametric ΔBP_ND estimates within the striatum.

The Impact of Job Loss on Self-injury Mortality in a Cohort of Autoworkers: Application of a Novel Causal Approach

BACKGROUND

Recent increases in national rates of suicide and fatal overdose have been linked to a deterioration of economic and social stability. The American auto industry experienced comparable pressures beginning in the 1980s with the emergence of a competitive global market.

METHODS

Using the United Autoworkers-General Motors (GM) cohort as a case study, we examine the impact of employment loss on these self-injury mortality events. For 29,538 autoworkers employed on or after 1 January 1970, we apply incremental propensity score interventions, a novel causal inference approach, to examine how proportional shifts in the odds of leaving active GM employment affect the cumulative incidence of self-injury mortality.

RESULTS

Cumulative incidence of self-injury mortality was 0.87% (255 cases) at the observed odds of leaving active GM employment (δ = 1) over a 45-year period. A 10% decrease in the odds of leaving active GM employment (δ = 0.9) results in an estimated 8% drop in self-injury mortality (234 cases) while a 10% increase (δ = 1.1) results in a 19% increase in self-injury mortality (303 cases).

CONCLUSIONS

These results are consistent with the hypothesis that leaving active employment at GM increases the risk of death due to suicide or drug overdose.

Reproducibility of cerebrovascular reactivity measurements: A systematic review of neuroimaging techniques. J Cereb Blood Flow Metab 2022;42:700-717. [PMID: 34806918 PMCID: PMC9254040 DOI: 10.1177/0271678x211056702]

Cerebrovascular reactivity (CVR), the capacity of the brain to increase cerebral blood flow (CBF) to meet changes in physiological demand, is an important biomarker to evaluate brain health. Typically, this brain "stress test" is performed by using a medical imaging modality to measure the CBF change between two states: at baseline and after vasodilation. However, since there are many imaging modalities and many ways to augment CBF, a wide range of CVR values have been reported. An understanding of CVR reproducibility is critical to determine the most reliable methods to measure CVR as a clinical biomarker. This review focuses on CVR reproducibility studies using neuroimaging techniques in 32 articles comprising 427 total subjects. The literature search was performed in PubMed, Embase, and Scopus. The review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We identified 5 factors of the experimental subjects (such as sex, blood characteristics, and smoking) and 9 factors of the measuring technique (such as the imaging modality, the type of the vasodilator, and the quantification method) that have strong effects on CVR reproducibility. Based on this review, we recommend several best practices to improve the reproducibility of CVR quantification in neuroimaging studies.

Metalworking Fluid Exposure and Stroke Mortality Among US Autoworkers

Although air pollution is an important risk factor for stroke, few studies have considered the impact of workplace exposure to particulate matter (PM). We examined implications of exposure to PM composed of metalworking fluids (MWFs) for stroke mortality in the United Autoworkers-General Motors cohort. Cox proportional hazards models with age as the timescale were used to estimate the association of cumulative straight, soluble, and synthetic MWF exposure with stroke mortality, controlling for sex, race, plant, calendar year, and hire year. Among 38,553 autoworkers followed during 1941-1995, we identified 114 ischemic stroke deaths and 113 hemorrhagic stroke deaths. Overall stroke mortality risk was increased among workers in the middle exposure category for straight MWF (hazard ratio (HR) = 1.31, 95% confidence interval (CI): 0.87, 1.98) and workers in the highest exposure category for synthetic MWF (HR = 1.94, 95% CI: 1.13, 3.16) compared with workers who had no direct exposure. Ischemic stroke mortality risk was increased among workers in the highest exposure categories for straight MWF (HR = 1.45, 95% CI: 0.83, 2.52) and synthetic MWF (HR = 2.39, 95% CI: 1.39, 4.50). We observed no clear relationship between MWF exposure and hemorrhagic stroke mortality. Our results support a potentially important role for occupational PM exposures in stroke mortality and indicate the need for further studies of PM exposure and stroke in varied occupational settings.

True ultra-low-dose amyloid PET/MRI enhanced with deep learning for clinical interpretation

PURPOSE

While sampled or short-frame realizations have shown the potential power of deep learning to reduce radiation dose for PET images, evidence in true injected ultra-low-dose cases is lacking. Therefore, we evaluated deep learning enhancement using a significantly reduced injected radiotracer protocol for amyloid PET/MRI.

METHODS

Eighteen participants underwent two separate ¹⁸F-florbetaben PET/MRI studies in which an ultra-low-dose (6.64 ± 3.57 MBq, 2.2 ± 1.3% of standard) or a standard-dose (300 ± 14 MBq) was injected. The PET counts from the standard-dose list-mode data were also undersampled to approximate an ultra-low-dose session. A pre-trained convolutional neural network was fine-tuned using MR images and either the injected or sampled ultra-low-dose PET as inputs. Image quality of the enhanced images was evaluated using three metrics (peak signal-to-noise ratio, structural similarity, and root mean square error), as well as the coefficient of variation (CV) for regional standard uptake value ratios (SUVRs). Mean cerebral uptake was correlated across image types to assess the validity of the sampled realizations. To judge clinical performance, four trained readers scored image quality on a five-point scale (using 15% non-inferiority limits for proportion of studies rated 3 or better) and classified cases into amyloid-positive and negative studies.

RESULTS

The deep learning-enhanced PET images showed marked improvement on all quality metrics compared with the low-dose images as well as having generally similar regional CVs as the standard-dose. All enhanced images were non-inferior to their standard-dose counterparts. Accuracy for amyloid status was high (97.2% and 91.7% for images enhanced from injected and sampled ultra-low-dose data, respectively) which was similar to intra-reader reproducibility of standard-dose images (98.6%).

CONCLUSION

Deep learning methods can synthesize diagnostic-quality PET images from ultra-low injected dose simultaneous PET/MRI data, demonstrating the general validity of sampled realizations and the potential to reduce dose significantly for amyloid imaging.

Persistently Elevated mTOR Complex 1-S6 Kinase 1 Disrupts DARPP-32-Dependent D1 Dopamine Receptor Signaling and Behaviors

BACKGROUND

The serine-threonine kinase mTORC1 (mechanistic target of rapamycin complex 1) is essential for normal cell function but is aberrantly activated in the brain in both genetic-developmental and sporadic diseases and is associated with a spectrum of neuropsychiatric symptoms. The underlying molecular mechanisms of cognitive and neuropsychiatric symptoms remain controversial.

METHODS

The present study examines behaviors in transgenic models that express Rheb, the most proximal known activator of mTORC1, and profiles striatal phosphoproteomics in a model with persistently elevated mTORC1 signaling. Biochemistry, immunohistochemistry, electrophysiology, and behavior approaches are used to examine the impact of persistently elevated mTORC1 on D₁ dopamine receptor (D1R) signaling. The effect of persistently elevated mTORC1 was confirmed using D1-Cre to elevate mTORC1 activity in D1R neurons.

RESULTS

We report that persistently elevated mTORC1 signaling blocks canonical D1R signaling that is dependent on DARPP-32 (dopamine- and cAMP-regulated neuronal phosphoprotein). The immediate downstream effector of mTORC1, ribosomal S6 kinase 1 (S6K1), phosphorylates and activates DARPP-32. Persistent elevation of mTORC1-S6K1 occludes dynamic D1R signaling downstream of DARPP-32 and blocks multiple D1R responses, including dynamic gene expression, D1R-dependent corticostriatal plasticity, and D1R behavioral responses including sociability. Candidate biomarkers of mTORC1-DARPP-32 occlusion are increased in the brain of human disease subjects in association with elevated mTORC1-S6K1, supporting a role for this mechanism in cognitive disease.

CONCLUSIONS

The mTORC1-S6K1 intersection with D1R signaling provides a molecular framework to understand the effects of pathological mTORC1 activation on behavioral symptoms in neuropsychiatric disease.

Generalization of deep learning models for ultra-low-count amyloid PET/MRI using transfer learning

PURPOSE

We aimed to evaluate the performance of deep learning-based generalization of ultra-low-count amyloid PET/MRI enhancement when applied to studies acquired with different scanning hardware and protocols.

METHODS

Eighty simultaneous [18F]florbetaben PET/MRI studies were acquired, split equally between two sites (site 1: Signa PET/MRI, GE Healthcare, 39 participants, 67 ± 8 years, 23 females; site 2: mMR, Siemens Healthineers, 64 ± 11 years, 23 females) with different MRI protocols. Twenty minutes of list-mode PET data (90-110 min post-injection) were reconstructed as ground-truth. Ultra-low-count data obtained from undersampling by a factor of 100 (site 1) or the first minute of PET acquisition (site 2) were reconstructed for ultra-low-dose/ultra-short-time (1% dose and 5% time, respectively) PET images. A deep convolution neural network was pre-trained with site 1 data and either (A) directly applied or (B) trained further on site 2 data using transfer learning. Networks were also trained from scratch based on (C) site 2 data or (D) all data. Certified physicians determined amyloid uptake (+/-) status for accuracy and scored the image quality. The peak signal-to-noise ratio, structural similarity, and root-mean-squared error were calculated between images and their ground-truth counterparts. Mean regional standardized uptake value ratios (SUVR, reference region: cerebellar cortex) from 37 successful site 2 FreeSurfer segmentations were analyzed.

RESULTS

All network-synthesized images had reduced noise than their ultra-low-count reconstructions. Quantitatively, image metrics improved the most using method B, where SUVRs had the least variability from the ground-truth and the highest effect size to differentiate between positive and negative images. Method A images had lower accuracy and image quality than other methods; images synthesized from methods B-D scored similarly or better than the ground-truth images.

CONCLUSIONS

Deep learning can successfully produce diagnostic amyloid PET images from short frame reconstructions. Data bias should be considered when applying pre-trained deep ultra-low-count amyloid PET/MRI networks for generalization.

Suicide, overdose and worker exit in a cohort of Michigan autoworkers

BACKGROUND

In recent decades, suicide and fatal overdose rates have increased in the US, particularly for working-age adults with no college education. The coincident decline in manufacturing has limited stable employment options for this population. Erosion of the Michigan automobile industry provides a striking case study.

METHODS

We used individual-level data from a retrospective cohort study of 26 804 autoworkers in the United Autoworkers-General Motors cohort, using employment records from 1970 to 1994 and mortality follow-up from 1970 to 2015. We estimated HRs for suicide or fatal overdose in relation to leaving work, measured as active or inactive employment status and age at worker exit.

RESULTS

There were 257 deaths due to either suicide (n=202) or overdose (n=55); all but 21 events occurred after leaving work. The hazard rate for suicide was 16.1 times higher for inactive versus active workers (95% CI 9.8 to 26.5). HRs for suicide were elevated for all younger age groups relative to those leaving work after age 55. Those 30-39 years old at exit had the highest HR for suicide, 1.9 (95% CI 1.2 to 3.0). When overdose was included, the rate increased by twofold for both 19- to 29-year-olds and 30- to 39-year-olds at exit. Risks remained elevated when follow-up was restricted to 5 years after exit.

CONCLUSIONS

Autoworkers who left work had a higher risk of suicide or overdose than active employees. Those who left before retirement age had higher rates than those who left after, suggesting that leaving work early may increase the risk.

[Cochleo-vestibular lesions and prognosis in patients with profound sudden sensorineural hearing loss: a comparative analysis]

Objective: To investigate the characteristics of cochleo-vestibular dysfunction in patients with profound sudden deafness, and the prognosis of inner ear hemorrhage. Methods: From January 2017 to December 2018, 92 inpatients with profound sudden sensorineural hearing loss were enrolled in the Department of Otorhinolaryngology, First Affiliated Hospital of Sun Yat-sen University. Our studied patients included 47 males and 45 females, aged 20-78 (39.3±6.1) years. According to the results of inner ear magnetic resonance imaging (MRI), the patients were divided into two groups: inner ear hemorrhage group and non-inner ear hemorrhage group. The clinical features, vestibular tests and audiological examination results during follow up were compared between the two groups. SPSS 22.0 software was used for statistical analysis. Results: The inner ear hemorrhage group consisted of 32 cases (34.8%, 32/92), all of whom complained of vertigo (100%, 32/32). Simultaneous vertigo attack and hearing loss occurred in 78.1% of this group (24/32). Neither semicircular canals function, nor cervical vestibular evoked myogenic potential (c-VEMP), nor ocular vestibular evoked myogenic potential (o-VEMP) in the affected side was normal (100%, 32/32). The rates of benign paroxysmal positional vertigo (BPPV) and disequilibrium were 37.5% (12/32) and 25.0% (8/32) respectively. Hearing improved in 28.1% (9/32) two weeks after treatment, and became stable at one month's follow up. In 60 cases without inner ear hemorrhage, 58.3% of them (35/60) experienced vertigo, which occurred simultaneously with hearing loss in 21 patients (60%, 21/35). The abnormal rates of semicircular canals function, c-VEMP and o-VEMP were 71.6% (43/60), 78.3% (47/60) and 66.7% (40/60), respectively. The incidence of BPPV was 16.7% (10/60) and 8.3% (5/60) in cases with disequilibrium. Hearing improved in 58.3% (35/60) two week after treatment, and became stable at three months' follow up. Significant difference was found in either vertigo rate, or simultaneous vertigo/hearing loss rate, or abnormal c-VEMP/o-VEMP rates, or accompanying BPPV, or disequilibrium rates between the two groups (P<0.05 each). Moreover, we observed better hearing recovery in non-inner ear hemorrhage group in the two weeks, one month, three months and six months' follow up, when compared with those in inner ear hemorrhage groups (P<0.05 each). Conclusions: Inner ear hemorrhage is associated with more severe cochlea-vestibular lesion and poorer prognosis, in comparison to the non-inner ear hemorrhage,in patients with profound sudden sensorineural hearing loss.

Ultra-low-dose PET reconstruction using generative adversarial network with feature matching and task-specific perceptual loss

PURPOSE

Our goal was to use a generative adversarial network (GAN) with feature matching and task-specific perceptual loss to synthesize standard-dose amyloid Positron emission tomography (PET) images of high quality and including accurate pathological features from ultra-low-dose PET images only.

METHODS

Forty PET datasets from 39 participants were acquired with a simultaneous PET/MRI scanner following injection of 330 ± 30 MBq of the amyloid radiotracer 18F-florbetaben. The raw list-mode PET data were reconstructed as the standard-dose ground truth and were randomly undersampled by a factor of 100 to reconstruct 1% low-dose PET scans. A 2D encoder-decoder network was implemented as the generator to synthesize a standard-dose image and a discriminator was used to evaluate them. The two networks contested with each other to achieve high-visual quality PET from the ultra-low-dose PET. Multi-slice inputs were used to reduce noise by providing the network with 2.5D information. Feature matching was applied to reduce hallucinated structures. Task-specific perceptual loss was designed to maintain the correct pathological features. The image quality was evaluated by peak signal-to-noise ratio (PSNR), structural similarity (SSIM), and root mean square error (RMSE) metrics with and without each of these modules. Two expert radiologists were asked to score image quality on a 5-point scale and identified the amyloid status (positive or negative).

RESULTS

With only low-dose PET as input, the proposed method significantly outperformed Chen et al.'s method (Chen et al. Radiology. 2018;290:649-656) (which shows the best performance in this task) with the same input (PET-only model) by 1.87 dB in PSNR, 2.04% in SSIM, and 24.75% in RMSE. It also achieved comparable results to Chen et al.'s method which used additional magnetic resonance imaging (MRI) inputs (PET-MR model). Experts' reading results showed that the proposed method could achieve better overall image quality and maintain better pathological features indicating amyloid status than both PET-only and PET-MR models proposed by Chen et al. CONCLUSION: Standard-dose amyloid PET images can be synthesized from ultra-low-dose images using GAN. Applying adversarial learning, feature matching, and task-specific perceptual loss are essential to ensure image quality and the preservation of pathological features.

[Clinical characteristics and etiological analysis of sudden deafness patients with vertigo]

Objective: To explore the possible causes and mechanisms of sudden deafness with vertigo. Methods: Between August 2016 and December 2017, 74 patients with sudden deafness and vertigo were hospitalized in the Department of Otolaryngology, First Affiliated Hospital of Sun Yat-sen University. Among them, 36 were male and 38 were female, aged 18-75 (40.5±6.5) years. According to the results of magnetic resonance imaging (MRI), the patients were divided into two groups: internal ear hemorrhage (IEH) and non-IEH (NIEH). The characteristics of deafness, vertigo, laboratory examination and follow-up results were compared between the two groups. Results: In IEH group, deafness and vertigo occurred simultaneously in 22 cases (84.6%), abnormalities of semicircular canal function, cervical vestibular evoked myogenic potential (C-VEMP), ocular vestibular evoked myogenic potential (O-VEMP) in 26 cases (100%) and benign paroxysmal positional vertigo (BPPV) in 10 cases (38.5%). The total effective rate was 19.2% (5/26) after 14 days of treatment, and 11 cases (42.3%) appeared disturbance after 180 days of treatment. The abnormal rate of lateral vestibular function, C-VEMP and O-VEMP was 69.2% (18/26), 53.8% (14/26) and 57.7% (15/26) respectively. The improvement of hearing threshold was (28.6±9.7) dB. In NIEH group, deafness and vertigo occurred simultaneously in 25 cases (52.1%). The abnormalities of semicircular canal function, C-VEMP and O-VEMP happened in 37 cases (77.1%), 34 cases (70.8%), 26 cases (54.2%), respectively, and 6 cases (12.5%) were of BPPV. The total effective rate was 52.1% (25/48) after 14 days of treatment. After 180 days of treatment, 8 cases (16.7%) were out of balance, and the abnormal rate of lateral vestibular function, C-VEMP and O-VEMP were 31.2% (15/48), 25.0% (12/48) and 20.8% (10/48) respectively. The improvement of hearing threshold was (42.5±10.3) dB. The incidence of stimulantous deafness and vertigo, vestibular dysfunction rate, BPPV incidence rate and the total effective rate after 14 days of treatment were significantly different between the two groups (all P<0.05). The vestibular and cochlear dysfunction in IEH group was more serious than that in NIEH group. After 180 days of treatment, the vestibular dysfunction rate, imbalance rate and improvement of hearing threshold in NIEH group were significantly higher than that in IEH group (all P<0.05). The recovery of vestibular and cochlear function in NIEH group was better than that in IEH group. Conclusions: Sudden deafness with vertigo can cause vestibular and cochlear dysfunction. Different etiologies may lead to different clinical features and prognosis. The vestibular and cochlear function damage caused by inner ear hemorrhage was more serious and the recovery effect was poor.

[Clinical study of inner ear hemorrhage-associated sudden deafness and vertigo]

Objective: To analyze the clinical features and possible pathogenesis of sudden deafenss and vertigo induced by inner ear hemorrhage. Methods: Clinical data of 30 patients with inner ear hemorrhage, from the first affiliated hospital of Sun Yat-sen university during Jan 2016 to May 2017, were retrospectively analyzed. Results: Vergito and profound deafness were seen in all patients. The duration of vertigo ranged from 24 hours to three days in 11 cases, three to 14 days in the remaining 19 cases. Simultaneous occurrence of vergito and deafenss were seen in 24 patients. Semicircular canal hypofunction and abnormal cervical vestibular evoked myogenic potentials(C-VEMP)/ocular vestibular evoked myogenic potentials(O-VEMP) were detected in all cases. Ten patients had benign paroxysmal positional vertigo(BPPV) simultaneously. Hearing recovered in 20% of the cohort posttreatment. Dizziness and balance disturbance disappeared 1 to 2 months after therapy in 16 cases. Long term (6 months) follow up revealed poor hearing outcome and vestibular rehabilitation. Conclusion: Vestibular vertigo and profound sensorineural hearing loss, with unsatisfactory clinical prognosis, constituted the characters of inner ear hemorrhage-associated sudden deafness.

Ultra-Low-Dose 18F-Florbetaben Amyloid PET Imaging Using Deep Learning with Multi-Contrast MRI Inputs

Purpose To reduce radiotracer requirements for amyloid PET/MRI without sacrificing diagnostic quality by using deep learning methods. Materials and Methods Forty data sets from 39 patients (mean age ± standard deviation [SD], 67 years ± 8), including 16 male patients and 23 female patients (mean age, 66 years ± 6 and 68 years ± 9, respectively), who underwent simultaneous amyloid (fluorine 18 [18F]-florbetaben) PET/MRI examinations were acquired from March 2016 through October 2017 and retrospectively analyzed. One hundredth of the raw list-mode PET data were randomly chosen to simulate a low-dose (1%) acquisition. Convolutional neural networks were implemented with low-dose PET and multiple MR images (PET-plus-MR model) or with low-dose PET alone (PET-only) as inputs to predict full-dose PET images. Quality of the synthesized images was evaluated while Bland-Altman plots assessed the agreement of regional standard uptake value ratios (SUVRs) between image types. Two readers scored image quality on a five-point scale (5 = excellent) and determined amyloid status (positive or negative). Statistical analyses were carried out to assess the difference of image quality metrics and reader agreement and to determine confidence intervals (CIs) for reading results. Results The synthesized images (especially from the PET-plus-MR model) showed marked improvement on all quality metrics compared with the low-dose image. All PET-plus-MR images scored 3 or higher, with proportions of images rated greater than 3 similar to those for the full-dose images (-10% difference [eight of 80 readings], 95% CI: -15%, -5%). Accuracy for amyloid status was high (71 of 80 readings [89%]) and similar to intrareader reproducibility of full-dose images (73 of 80 [91%]). The PET-plus-MR model also had the smallest mean and variance for SUVR difference to full-dose images. Conclusion Simultaneously acquired MRI and ultra-low-dose PET data can be used to synthesize full-dose-like amyloid PET images. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Catana in this issue.

Corrections to "Direct Patlak Reconstruction From Dynamic PET Data Using the Kernel Method With MRI Information Based on Structural Similarity"

In the above paper [1], there are typos in Algorithm 1 table. The correct version of Algorithm 1 is given below.

An Efficient Approach to Perform MR-assisted PET Data Optimization in Simultaneous PET/MR Neuroimaging Studies

A main advantage of PET is that it provides quantitative measures of the radiotracer concentration, but its accuracy is confounded by several factors, including attenuation, subject motion, and limited spatial resolution. Using the information from one simultaneously acquired morphological MR sequence with embedded navigators, we propose an efficient method called MR-assisted PET data optimization (MaPET) to perform attenuation correction (AC), motion correction, and anatomy-aided reconstruction. Methods: For attenuation correction, voxel-wise linear attenuation coefficient maps were generated using an SPM8-based approach method on the MR volume. The embedded navigators were used to derive head motion estimates for event-based PET motion correction. The anatomy provided by the MR volume was incorporated into the PET image reconstruction using a kernel-based method. Region-based analyses were carried out to assess the quality of images generated through various stages of PET data optimization. Results: The optimized PET images reconstructed with MaPET was superior in image quality compared to images reconstructed using only attenuation correction, with high SNR and low coefficient of variation (5.08 and 0.229 in a composite cortical region compared to 3.12 and 0.570). The optimized images were also shown using the Cohen's d metric to achieve a greater effect size in distinguishing cortical regions with hypometabolism from regions of preserved metabolism in each individual for different diagnosis groups. Conclusion: We have shown the spatiotemporally correlated data acquired using a single MR sequence can be used for PET attenuation, motion and partial volume effects corrections and the MaPET method may enable more accurate assessment of pathological changes in dementia and other brain disorders.

Direct Patlak Reconstruction From Dynamic PET Data Using the Kernel Method With MRI Information Based on Structural Similarity

Positron emission tomography (PET) is a functional imaging modality widely used in oncology, cardiology, and neuroscience. It is highly sensitive, but suffers from relatively poor spatial resolution, as compared with anatomical imaging modalities, such as magnetic resonance imaging (MRI). With the recent development of combined PET/MR systems, we can improve the PET image quality by incorporating MR information into image reconstruction. Previously, kernel learning has been successfully embedded into static and dynamic PET image reconstruction using either PET temporal or MRI information. Here, we combine both PET temporal and MRI information adaptively to improve the quality of direct Patlak reconstruction. We examined different approaches to combine the PET and MRI information in kernel learning to address the issue of potential mismatches between MRI and PET signals. Computer simulations and hybrid real-patient data acquired on a simultaneous PET/MR scanner were used to evaluate the proposed methods. Results show that the method that combines PET temporal information and MRI spatial information adaptively based on the structure similarity index has the best performance in terms of noise reduction and resolution improvement.

MR-assisted PET motion correction in simultaneous PET/MRI studies of dementia subjects

BACKGROUND

Subject motion in positron emission tomography (PET) studies leads to image blurring and artifacts; simultaneously acquired magnetic resonance imaging (MRI) data provides a means for motion correction (MC) in integrated PET/MRI scanners.

PURPOSE

To assess the effect of realistic head motion and MR-based MC on static [¹⁸ F]-fluorodeoxyglucose (FDG) PET images in dementia patients.

STUDY TYPE

Observational study.

POPULATION

Thirty dementia subjects were recruited.

FIELD STRENGTH/SEQUENCE

3T hybrid PET/MR scanner where EPI-based and T₁ -weighted sequences were acquired simultaneously with the PET data.

ASSESSMENT

Head motion parameters estimated from high temporal resolution MR volumes were used for PET MC. The MR-based MC method was compared to PET frame-based MC methods in which motion parameters were estimated by coregistering 5-minute frames before and after accounting for the attenuation-emission mismatch. The relative changes in standardized uptake value ratios (SUVRs) between the PET volumes processed with the various MC methods, without MC, and the PET volumes with simulated motion were compared in relevant brain regions.

STATISTICAL TESTS

The absolute value of the regional SUVR relative change was assessed with pairwise paired t-tests testing at the P = 0.05 level, comparing the values obtained through different MR-based MC processing methods as well as across different motion groups. The intraregion voxelwise variability of regional SUVRs obtained through different MR-based MC processing methods was also assessed with pairwise paired t-tests testing at the P = 0.05 level.

RESULTS

MC had a greater impact on PET data quantification in subjects with larger amplitude motion (higher than 18% in the medial orbitofrontal cortex) and greater changes were generally observed for the MR-based MC method compared to the frame-based methods. Furthermore, a mean relative change of ∼4% was observed after MC even at the group level, suggesting the importance of routinely applying this correction. The intraregion voxelwise variability of regional SUVRs was also decreased using MR-based MC. All comparisons were significant at the P = 0.05 level.

DATA CONCLUSION

Incorporating temporally correlated MR data to account for intraframe motion has a positive impact on the FDG PET image quality and data quantification in dementia patients.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1288-1296.

Elevated Aminotransferases are Predictors of Hepatic Injury in Blunt Abdominal Trauma Patients

Objective

Computed tomography (CT) scan is currently the most commonly used tool for evaluating solid-organ injuries in trauma management. However, liberal use of CT scanning increases the risk of excess radiation exposure and toxicity from contrast material. Animal studies and clinical research on the paediatric population indicated that liver enzymes elevations were related to hepatic injury. The present study was undertaken to determine whether elevated liver enzymes were associated with the occurrence of hepatic injury in adult patients with blunt abdominal trauma.

Methods

This is a cross-sectional study from August 2003 to October 2006. All adult patients with blunt injury to abdomino-pelvic organs documented by CT or surgery who were admitted to Chi-Mei Medical Centre in the captioned period were included. The study population sorted to hepatic injury (HI) and no hepatic injury (NHI) groups according to the presence or absence of hepatic injury. Variables including liver enzymes were compared between the groups.

Results

Totally 419 patients were included, including 150 patients in the HI group and 269 patients in the NHI group. The HI group was younger and had a lower rate of laparotomy (36.3 years old vs 41.4 years old; 26% vs 42%, respectively). The mean levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HI group were significantly higher than levels in the NHI group (439.6 IU/L vs 104.7 IU/L; 353.5 IU/L vs 76.6 IU/L, p<0.01). We define AST >200 IU/L or ALT level >125 IU/L as abnormal according to previous studies. The diagnostic characteristics of hepatic injury were 87.3% sensitivity, 80.3% specificity, 71.2% positive predictive value, and 91.9% negative predictive value.

Conclusion

In adults who have experienced blunt abdominal trauma, AST >200 U/L or of ALT >125 U/L are practical predictors of hepatic injury. Screening serum aminotransferases will have a role in detecting occult hepatic injury and may reduce the hazards of excessive CT scanning. (Hong Kong j.emerg.med. 2013;20:337-342)

Severe Hyperemesis Gravidarum Masking the Presentations of Hyperthyroidism

Hyperemesis gravidarum may present with weight loss and tachycardia secondary to dehydration. Its severity correlates with the level of the serum chorionic gonadotropin which can interfere with the assay of the thyroid stimulating hormone. Therefore, hyperemesis gravidarum are at times difficult to be distinguished from hyperthyroidism. Missing hyperthyroidism during pregnancy results not only in inappropriate maternal care, but adverse neonatal outcomes including low birth weight. The authors report a case of hyperemesis gravidarum complicated by the concurrence of hyperthyroidism. Goiter and refractory tachycardia are the useful clues to detect occult hyperthyroidism in patients with hyperemesis gravidarum.

Anatomically-aided PET reconstruction using the kernel method

This paper extends the kernel method that was proposed previously for dynamic PET reconstruction, to incorporate anatomical side information into the PET reconstruction model. In contrast to existing methods that incorporate anatomical information using a penalized likelihood framework, the proposed method incorporates this information in the simpler maximum likelihood (ML) formulation and is amenable to ordered subsets. The new method also does not require any segmentation of the anatomical image to obtain edge information. We compare the kernel method with the Bowsher method for anatomically-aided PET image reconstruction through a simulated data set. Computer simulations demonstrate that the kernel method offers advantages over the Bowsher method in region of interest quantification. Additionally the kernel method is applied to a 3D patient data set. The kernel method results in reduced noise at a matched contrast level compared with the conventional ML expectation maximization algorithm.

An SPM8-based approach for attenuation correction combining segmentation and nonrigid template formation: application to simultaneous PET/MR brain imaging

We present an approach for head MR-based attenuation correction (AC) based on the Statistical Parametric Mapping 8 (SPM8) software, which combines segmentation- and atlas-based features to provide a robust technique to generate attenuation maps (μ maps) from MR data in integrated PET/MR scanners.

METHODS

Coregistered anatomic MR and CT images of 15 glioblastoma subjects were used to generate the templates. The MR images from these subjects were first segmented into 6 tissue classes (gray matter, white matter, cerebrospinal fluid, bone, soft tissue, and air), which were then nonrigidly coregistered using a diffeomorphic approach. A similar procedure was used to coregister the anatomic MR data for a new subject to the template. Finally, the CT-like images obtained by applying the inverse transformations were converted to linear attenuation coefficients to be used for AC of PET data. The method was validated on 16 new subjects with brain tumors (n = 12) or mild cognitive impairment (n = 4) who underwent CT and PET/MR scans. The μ maps and corresponding reconstructed PET images were compared with those obtained using the gold standard CT-based approach and the Dixon-based method available on the Biograph mMR scanner. Relative change (RC) images were generated in each case, and voxel- and region-of-interest-based analyses were performed.

RESULTS

The leave-one-out cross-validation analysis of the data from the 15 atlas-generation subjects showed small errors in brain linear attenuation coefficients (RC, 1.38% ± 4.52%) compared with the gold standard. Similar results (RC, 1.86% ± 4.06%) were obtained from the analysis of the atlas-validation datasets. The voxel- and region-of-interest-based analysis of the corresponding reconstructed PET images revealed quantification errors of 3.87% ± 5.0% and 2.74% ± 2.28%, respectively. The Dixon-based method performed substantially worse (the mean RC values were 13.0% ± 10.25% and 9.38% ± 4.97%, respectively). Areas closer to the skull showed the largest improvement.

CONCLUSION

We have presented an SPM8-based approach for deriving the head μ map from MR data to be used for PET AC in integrated PET/MR scanners. Its implementation is straightforward and requires only the morphologic data acquired with a single MR sequence. The method is accurate and robust, combining the strengths of both segmentation- and atlas-based approaches while minimizing their drawbacks.

Probabilistic atlas-based segmentation of combined T1-weighted and DUTE MRI for calculation of head attenuation maps in integrated PET/MRI scanners

We present a new MRI-based attenuation correction (AC) approach for integrated PET/MRI systems that combines both segmentation- and atlas-based methods by incorporating dual-echo ultra-short echo-time (DUTE) and T1-weighted (T1w) MRI data and a probabilistic atlas. Segmented atlases were constructed from CT training data using a leave-one-out framework and combined with T1w, DUTE, and CT data to train a classifier that computes the probability of air/soft tissue/bone at each voxel. This classifier was applied to segment the MRI of the subject of interest and attenuation maps (μ-maps) were generated by assigning specific linear attenuation coefficients (LACs) to each tissue class. The μ-maps generated with this "Atlas-T1w-DUTE" approach were compared to those obtained from DUTE data using a previously proposed method. For validation of the segmentation results, segmented CT μ-maps were considered to the "silver standard"; the segmentation accuracy was assessed qualitatively and quantitatively through calculation of the Dice similarity coefficient (DSC). Relative change (RC) maps between the CT and MRI-based attenuation corrected PET volumes were also calculated for a global voxel-wise assessment of the reconstruction results. The μ-maps obtained using the Atlas-T1w-DUTE classifier agreed well with those derived from CT; the mean DSCs for the Atlas-T1w-DUTE-based μ-maps across all subjects were higher than those for DUTE-based μ-maps; the atlas-based μ-maps also showed a lower percentage of misclassified voxels across all subjects. RC maps from the atlas-based technique also demonstrated improvement in the PET data compared to the DUTE method, both globally as well as regionally.

Factors affecting the use of anti-amoebiasis protective measures among Taiwan immigrants returning to amoebiasis-endemic regions

OBJECTIVE

To investigate the predictors of use of anti-amoebiasis protective measures (AAPMs) among Taiwan immigrants returning to their country of origin, using the Health Belief Model (HBM) to guide the investigation.

DESIGN

Cross-sectional study.

METHODS

Between March and May 2011, all permanent immigrants originating from amoebiasis-endemic countries who received services at the immigrant service centres in Taipei or Tainan and who reported that they had returned to their country of origin within the past five years were enrolled in the study. A structured questionnaire containing questions on sociodemographic characteristics and items related to the constructs of the HBM was used as the data collection instrument.

RESULTS

Complete information was collected from 384 immigrants, with a response rate of 80% (384/480). The mean age of the subjects was 38.4 years (standard deviation 10.6 years). The majority (70%) of participants did not receive travel information through a pretravel consultation, and more than 17% reported that they did not use measures to prevent amoebiasis. Multiple regression analyses revealed that Chinese proficiency, pretravel consultation and lower barriers to using protective measures were significantly associated with the use of AAPMs during return trips to country of origin (R(2) = 0.45; F = 77.5; P < 0.001).

CONCLUSION

The HBM significantly predicted the use of AAPMs in this study. A high proportion of immigrants did not use appropriate AAPMs when they returned to their country of origin. Educational approaches should be targeted at immigrants originating from amoebiasis-endemic regions who return to their country of origin.

Conjunctival Inclusion Cyst

Conjunctival inclusion cysts are the most common cystic lesions of the conjunctiva and are either congenital or acquired; the latter are more prevalent. Some of the major factors that provoke the development of an acquired cyst are surgery, trauma, and chronic inflammation. Here, we report on a conjunctival inclusion cyst that developed following a case of untreated chronic conjunctivitis. To temporarily relieve the patient's symptoms a needle aspiration of the cyst was performed, and the patient was referred to an ophthalmologist for surgical excision of the cyst.

Cerebral “eThrombosis”: Cerebral Venous Sinus Thrombosis Associated with Prolonged Sitting in Front of a Computer

Venous thromboembolism caused by prolonged sitting during air travel has been recognised as economy-class syndrome for more than 30 years. Since 2003, the term “eThrombosis” has been proposed to describe the 21st Century variant of venous thromboembolism associated with immobilisation. We reported a case of cerebral venous sinus thrombosis presenting with severe headache after a prolonged period of sitting for over 12 hours in front of a computer for recreational purpose. We described this case as cerebral “eThrombosis”. Considering the widespread use of computers for many purposes including working, recreation and communications in the present digital era, we would like to put forward that prolonged immobilisation associated with computer use is a possible provoking risk factor of cerebral venous sinus thrombosis.

Severe Hyperemesis Gravidarum Masking the Presentations of Hyperthyroidism

Hyperemesis gravidarum may present with weight loss and tachycardia secondary to dehydration. Its severity correlates with the level of the serum chorionic gonadotropin which can interfere with the assay of the thyroid stimulating hormone. Therefore, hyperemesis gravidarum are at times difficult to be distinguished from hyperthyroidism. Missing hyperthyroidism during pregnancy results not only in inappropriate maternal care, but adverse neonatal outcomes including low birth weight. The authors report a case of hyperemesis gravidarum complicated by the concurrence of hyperthyroidism. Goiter and refractory tachycardia are the useful clues to detect occult hyperthyroidism in patients with hyperemesis gravidarum.

Capnography: An Accurate Method to Assess the Position of the Feeding Tube in a Porcine Model

Objective

To test the accuracy of capnography in the differential placement of feeding tubes into the trachea versus the oesophagus.

Method

Nineteen pigs were anesthetised, and feeding tubes were placed into their tracheas and oesophagi. A naïve examiner attached a capnography to the tube and evaluated the presence or absence of flow waveforms on the capnography. In the next step experiment, we gave 20 intentional oesophageal ventilations to the animals to create a distended stomach. The feeding tubes were reinserted, and examined by a naïve examiner by capnography.

Results

Capnography demonstrated continuous flow waveforms for the feeding tubes placed in the tracheas, but no waveforms were observed for those placed in the oesophagi. In the next step experiment, we found the same results.

Conclusion

Capnography can be used to accurately determine the placement of tracheal versus oesophageal feeding tubes based on the presence or absence of flow waveforms.

Intestinal alkaline phosphatase preserves the normal homeostasis of gut microbiota

BACKGROUND AND AIMS

The intestinal microbiota plays a critical role in maintaining human health; however, the mechanisms governing the normal homeostatic number and composition of these microbes are largely unknown. Previously it was shown that intestinal alkaline phosphatase (IAP), a small intestinal brush border enzyme, functions as a gut mucosal defence factor limiting the translocation of gut bacteria to mesenteric lymph nodes. In this study the role of IAP in the preservation of the normal homeostasis of the gut microbiota was investigated.

METHODS

Bacterial culture was performed in aerobic and anaerobic conditions to quantify the number of bacteria in the stools of wild-type (WT) and IAP knockout (IAP-KO) C57BL/6 mice. Terminal restriction fragment length polymorphism, phylogenetic analyses and quantitative real-time PCR of subphylum-specific bacterial 16S rRNA genes were used to determine the compositional profiles of microbiotas. Oral supplementation of calf IAP (cIAP) was used to determine its effects on the recovery of commensal gut microbiota after antibiotic treatment and also on the colonisation of pathogenic bacteria.

RESULTS

IAP-KO mice had dramatically fewer and also different types of aerobic and anaerobic microbes in their stools compared with WT mice. Oral supplementation of IAP favoured the growth of commensal bacteria, enhanced restoration of gut microbiota lost due to antibiotic treatment and inhibited the growth of a pathogenic bacterium (Salmonella typhimurium).

CONCLUSIONS

IAP is involved in the maintenance of normal gut microbial homeostasis and may have therapeutic potential against dysbiosis and pathogenic infections.

Comparison of photodegradative efficiencies and mechanisms of Victoria Blue R assisted by Nafion-coated and fluorinated TiO2 photocatalysts

The purposes of this research were to study the effects of two modified photocatalysts, Nafion-coated TiO(2) and fluorinated TiO(2), and photocatalytic degradation of Victoria Blue R in aqueous solution. Photocatalytic degradation of Victoria Blue R was accelerated by the modified photocatalysts. Bulk and surface characterizations of the resulting powders were carried out. Attachment of the anions to the TiO(2) surface using the Nafion-coated-TiO(2) possibly results in increased adsorption of the cationic dye, and the degradation rate is larger for the cationic dye. It was found that Victoria Blue R on the two illuminated TiO(2) surfaces underwent very different changes. To obtain a better understanding on the mechanistic details of this modified-TiO(2)-assisted photodegradation of the Victoria Blue R dye with UV irradiation, a large number of intermediates of the process were separated, identified, and characterized by a high-performance liquid chromatography-mass spectrometry technique. Several probable photodegradation pathways were proposed and discussed.

Impact of GB virus type C infection on mother-to-child HIV transmission in the Women and Infants Transmission Study Cohort

BACKGROUND

GB virus type C (GBV-C) viraemia is associated with a beneficial outcome in HIV-infected individuals in several though not all studies. GBV-C viraemia was examined in a matched case-control study of 133 HIV-infected pregnant women who transmitted HIV to their infants ('cases') and 266 non-transmitting controls.

METHODS

HIV-infected children and controls were pair-matched for high-risk delivery, race and year of delivery. GBV-C status was determined in maternal plasma samples obtained at or within 3 months of delivery.

RESULTS

Pregnant women with GBV-C viraemia (11% of those studied) had lower HIV RNA levels (P=0.01) and higher CD4 percentages (P=0.0006) [corrected] than women without GBV-C. A trend towards decreased mother-to-child transmission in the multivariate analysis was observed among GBV-C viraemic women delivering after highly active antiretroviral therapy (HAART) became available [odds ratio (OR) 0.30, 95% confidence interval (CI) 0.08-1.05; P=0.06], but not in women delivering prior to the widespread use of HAART.

CONCLUSIONS

GBV-C viraemia was associated with a beneficial effect on CD4 percentage and HIV RNA level in these pregnant women, and was also associated with a trend towards reduced risk of mother-to-child HIV transmission among women after HAART became available. Further studies with larger or multiple cohorts are necessary to assess possible benefits in this population.

Detection of oesophageal intubations using cuff pressures in a pig trachea–oesophagus model

BACKGROUND

The cuff pressures may be different in oesophageal and tracheal intubations. We conducted a study to evaluate if cuff pressures of endotracheal tubes (ETTs) could provide information to distinguish tracheal or oesophageal intubations in a pig trachea-oesophagus model.

METHODS

In each preparation of pig trachea-oesophagus model, the trachea and the oesophagus were intubated separately with a cuffed ETT, and the cuff pressures were measured after each 1 ml increment of air (1-10 ml) during inflation. The cuff pressures and the pressure-volume relationships in both intubations were compared.

RESULTS

The cuff pressures of oesophageal intubations were significantly higher than those of tracheal intubations in all comparisons from 1 to 10 ml of cuff volumes (P < 0.05). The cuff pressure-volume curve was steeper in the oesophageal intubation group, and the difference between the two curves was the largest when the cuff volume was 4-5 ml.

CONCLUSIONS

We conclude that the cuff pressures may be useful in detecting oesophageal intubations. This method is faster than other confirmation measures as it can detect inadvertent oesophageal intubations at the time of inflating the cuffs.

Life expectancy of patients with newly-diagnosed HIV infection in the era of highly active antiretroviral therapy

BACKGROUND

Limited data are available on the life expectancy of patients with newly-diagnosed HIV infection in the era of highly active antiretroviral therapy (HAART).

AIM

To provide such an estimate using a semi-parametric projection.

DESIGN

Statistical analysis.

METHODS

Follow-up data for patients newly diagnosed with HIV infection in Taiwan (HIV/AIDS Cohort) from 1 May 1997 to 30 April 2003 (n = 3351, only 1% are injecting drug users) were analysed using the Kaplan-Meier method. The survival function for an age- and gender-matched reference population was generated by the Monte Carlo method from the life-table of the general population. A constant excess hazard model was used to project long-term survival of HIV-infected patients, with linear extrapolation of a logit-transformed curve of survival ratio between HIV-infected patients and the reference population.

RESULTS

The 5-year survival rate was 58% in patients who had already developed AIDS at diagnosis (AIDS group), and 89% in those who had not (non-AIDS group). Extrapolation yielded an expected mean survival time of 10.6 years after diagnosis for the AIDS group, and 21.5 years after diagnosis for the non-AIDS group.

DISCUSSION

Our results support the expansion of HIV screening programs to minimize delay in diagnosis. With continuing advances in HAART, this estimate of survival in initially asymptomatic patients may be conservative. Their long life expectancy raises questions about what kind of preventive heath services should be offered. These should be addressed through further analysis of overall benefit and cost-effectiveness.

Br2 molecular elimination in 248nm photolysis of CHBr2Cl by using cavity ring-down absorption spectroscopy

Elimination of molecular bromine is probed in the B (3)Pi(ou) (+)<--X (1)Sigma(g) (+) transition following photodissociation of CHBr(2)Cl at 248 nm by using cavity ring-down absorption spectroscopy. The quantum yield for the Br(2) elimination reaction is determined to be 0.05+/-0.03. The nascent vibrational population ratio of Br(2)(v=1)Br(2)(v=0) is obtained to be 0.5+/-0.2. A supersonic beam of CHBr(2)Cl is similarly photofragmented and the resulting Br atoms are monitored with a velocity map ion-imaging detection, yielding spatial anisotropy parameters of 1.5 and 1.1 with photolyzing wavelengths of 234 and 267 nm, respectively. The results justify that the excited state promoted by 248 nm should have an A(") symmetry. Nevertheless, when CHBr(2)Cl is prepared in a supersonic molecular beam under a cold temperature, photofragmentation gives no Br(2) detectable in a time-of-flight mass spectrometer. A plausible pathway via internal conversion is proposed with the aid of ab initio potential energy calculations. Temperature dependence measurements lend support to the proposed pathway. The production rates of Br(2) between CHBr(2)Cl and CH(2)Br(2) are also compared to examine the chlorine-substituted effect.

248nm photolysis of CH2Br2 by using cavity ring-down absorption spectroscopy: Br2 molecular elimination at room temperature

Following photodissociation of CH2Br2 at 248 nm, Br2 molecular elimination is detected by using a tunable laser beam, as crossed perpendicular to the photolyzing laser beam in a ring-down cell, probing the Br2 fragment in the B 3Piou+ -X 1Sigmag+ transition. The nascent vibrational population is obtained, yielding a population ratio of Br2(v = 1)Br2(v = 0) to be 0.7 +/- 0.2. The quantum yield for the Br2 elimination reaction is determined to be 0.2 +/- 0.1. Nevertheless, when CH2Br2 is prepared in a supersonic molecular beam under cold temperature, photofragmentation gives no Br2 detectable in a time-of-flight mass spectrometer. With the aid of ab initio potential energy calculations, a plausible pathway is proposed. Upon excitation to the 1B1 or 3B1 state, C-Br bond elongation may change the molecular symmetry of Cs and enhance the resultant 1 1,3A'-X 1A' (or 1 1,3B1-X 1A1 as C2v is used) coupling to facilitate the process of internal conversion, followed by asynchronous concerted photodissociation. Temperature dependence measurements lend support to the proposed pathway.

Reaction of cyanoacetylene HCCCN(XΣ+1) with ground-state carbon atoms C(P3) in cold molecular clouds

The reaction of the simplest cyanopolyyne, cyanoacetylene [HCCCN(X (1)Sigma(+))], with ground-state atomic carbon C((3)P) is investigated theoretically to explore the probable routes for the depletion of the famed interstellar molecule HCCCN, and the formation of carbon-nitrogen-bearing species in extraterrestrial environments particularly of ultralow temperature. Six collision complexes (c1-c6) without entrance barrier as a result of the carbon atom addition to the pi systems of HCCCN are located. The optimized geometries and harmonic frequencies of the intermediates, transition states, and products along the isomerization and dissociation pathways of each collision complex are obtained by utilizing the unrestricted B3YLP6-311G(d,p) level of theory, and the corresponding CCSD(T)/cc-pVTZ energies are calculated. Subsequently, with the facilitation of Rice-Ramsperger-Kassel-Marcus (RRKM) and variational RRKM rate constants at collision energy of 0-10 kcal/mol, the most probable paths for the titled reaction are determined, and the product yields are estimated. Five collision complexes (c1-c3, c5, and c6) are predicted to give the same products, a chained CCCCN (p2)+H, via the linear and most stable intermediate, HCCCCN (i2), while collision complex c4 is likely to dissociate back to C+HCCCN. The study suggests that this class of reaction is an important route to the destruction of cyanoacetylene and cyanopolyynes in general, and to the synthesis of linear carbon-chained nitriles at the temperature as low as 10 K to be incorporated in future chemical models of interstellar clouds.

Re-emergence of meningococcal disease in Taiwan: circulation of domestic clones of Neisseria meningitidis in the 2001 outbreak

The annual incidence of meningococcal disease (meningitis and septicaemia) in Taiwan was 0.94/10(5) population in 1953. It then declined to below 0.001 from 1980 to 1987, and re-emerged in 2000 with a rate of 0.07/10(5) population. In 2001 there was a further increase in incidence (43 cases, 0.19/10(5)). Of 43 isolates of Neisseria meningitidis available for this study, including 41 from patients treated in 2001, three (7.0%) were penicillin insensitive (MIC > or = 0.12 microg/ml), though all were beta-lactamase negative: 16 (37.2%) were resistant to trimethoprim-sulphamethoxazole (MIC > or = 4/76 microg/ml). Serogrouping and genotype analysis revealed nine domestic clones. None of the 43 patients had any relationship (travel or contact history) with the 2000 or 2001 Hajj pilgrimage. Epidemiological information and typing results suggested wide dissemination of a limited number of domestic clones of N. meningitidis, manifesting as serogroups W-135, B and Y. Two clones of serogroup W-135 involved in the outbreak were genetically distinct from the 2000 or 2001 Hajj-related W-135 clone.

Coupled reduction of chlorinated hydrocarbons and heavy metals by zerovalent silicon

The feasibility of using zerovalent silicon (Si0) as a novel reductant to remove chlorinated compounds and heavy metals in contaminated sites was investigated. The kinetics and degradation mechanism of carbon tetrachloride (CT) by Si0 were also examined. Results showed that zerovalent silicon could effectively dechlorinate the chlorinated compounds. A nearly complete dechlorination of CT by Si0 was obtained within 14 h. The produced concentrations of chloroform (CF) accounted for 71-88% loss of CT, showing that reductive dechlorination is the major degradation pathway for the degradation of chlorinated hydrocarbons by Si0. The degradation followed pseudo first-order kinetics and the normalized surface reaction rate constant (k(sa)) for CT dechlorination ranged between 0.0342 and 0.0454 L m(-2) h(-1) when CT concentrations were in the range of 3-20 microM. A linear relationship between the k(sa) and pH value was also established. In addition, zerovalent silicon has a high capability in the removal of heavy metals. 83% of Cr(VI) was removed by 0.5g Si0 within 5 h, which is higher than that by Fe0. The removal efficiency of divalent metal ions by Si0 followed the order of Cu(II) > Pb(II) > Ni(II). This indicates that zerovalent silicon is an alternative reductant and can undergo coupled reduction of heavy metals and chlorinated hydrocarbons in contaminated groundwater.

Effects of huangqi jianzhong tang on hematological and biochemical parameters in judo athletes

AIM

The purpose of the study was to investigate the effects of Huangqi Jianzhong Tang (HQJZT) on hematological and biochemical parameters in judo athletes.

METHODS

Sixteen male and eight female judo athletes in Hsin-Ming senior high school were randomly and stratified divided into control and experimental group, which received placebo and HQJZT respectively during the five-week training program. The measurement of the hematological and biochemical parameters was performed twice, just before and after the training. The data was analyzed with paired-t test and ANOVA.

RESULTS

The values of RBC, Hb, and Hct were obvious decreased after intervention, while the value of GOT, GPT, BUN, and CK was elevated.

CONCLUSION

The results indicated the hematological and biochemical changes were caused by the physical training but not the effects of HQJZT. The HQJZT had no adverse effects on the judo athletes in our study.

A school waterborne outbreak involving both Shigella sonnei and Entamoeba histolytica

In an outbreak of gastroenteritis affecting 730 students, Shigella sonnei and Entamoeba histolytica were isolated from the stool specimens of patients. Environmental investigations revealed the source of infection to be contamination of underground well water by sewage from a toilet. The outbreak ended with the closure of the well water supply. To avoid such problems, institutions and other groups that maintain their own wells, including schools and summer camps, need to be vigilant about maintenance and check for potential contamination.