Compressed sensing with deep learning reconstruction: Improving capability of gadolinium-EOB-enhanced 3D T1WI

PURPOSE

The purpose of this study was to determine the utility of compressed sensing (CS) with deep learning reconstruction (DLR) for improving spatial resolution, image quality and focal liver lesion detection on high-resolution contrast-enhanced T1-weighted imaging (HR-CE-T1WI) obtained by CS with DLR as compared with conventional CE-T1WI with parallel imaging (PI).

METHODS

Seventy-seven participants with focal liver lesions underwent conventional CE-T1WI with PI and HR-CE-T1WI, surgical resection, transarterial chemoembolization, and radiofrequency ablation, followed by histopathological or >2-year follow-up examinations in our hospital. Signal-to-noise ratios (SNRs) of liver, spleen and kidney were calculated for each patient, after which each SNR was compared by means of paired t-test. To compare focal lesion detection capabilities of the two methods, a 5-point visual scoring system was adopted for a per lesion basis analysis. Jackknife free-response receiver operating characteristic (JAFROC) analysis was then performed, while sensitivity and false positive rates (/data set) for consensus assessment of the two methods were also compared by using McNemar's test or the signed rank test.

RESULTS

Each SNR of HR-CE-T1WI was significantly higher than that of conventional CE-T1WI with PI (p < 0.05). Sensitivities for consensus assessment showed that HR-CE-MRI had significantly higher sensitivity than conventional CE-T1WI with PI (p = 0.004). Moreover, there were significantly fewer FP/cases for HR-CE-T1WI than for conventional CE-T1WI with PI (p = 0.04).

CONCLUSION

CS with DLR are useful for improving spatial resolution, image quality and focal liver lesion detection capability of Gd-EOB-DTPA enhanced 3D T1WI without any need for longer breath-holding time.

Diffusion weighted imaging with reverse encoding distortion correction: Improvement of image quality and distortion for accurate ADC evaluation in in vitro and in vivo studies

PURPOSE

The purpose of this in vivo study was to determine the effect of reverse encoding direction (RDC) on apparent diffusion coefficient (ADC) measurements and its efficacy for improving image quality and diagnostic performance for differentiating malignant from benign tumors on head and neck diffusion-weighted imaging (DWI).

METHODS

Forty-eight patients with head and neck tumors underwent DWI with and without RDC and pathological examinations. Their tumors were then divided into two groups: malignant (n = 21) and benign (n = 27). To determine the utility of RDC for DWI, the difference in the deformation ratio (DR) between DWI and T2-weighted images of each tumor was determined for each tumor area. To compare ADC measurement accuracy of DWIs with and without RDC for each patient, ADC values for tumors and spinal cord were determined by using ROI measurements. To compare DR and ADC between two methods, Student's t-tests were performed. Then, ADC values were compared between malignant and benign tumors by Student's t-test on each DWI. Finally, sensitivity, specificity and accuracy were compared by means of McNemar's test.

RESULTS

DR of DWI with RDC was significantly smaller than that without RDC (p < 0.0001). There were significant differences in ADC between malignant and benign lesions on each DWI (p < 0.05). However, there were no significant difference of diagnostic accuracy between the two DWIs (p > 0.05).

CONCLUSION

RDC can improve image quality and distortion of DWI and may have potential for more accurate ADC evaluation and differentiation of malignant from benign head and neck tumors.

Species-differences in the in vitro biotransformation of trifluoroethene (HFO-1123)

1,1,2-Trifluoroethene (HFO-1123) is anticipated for use as a refrigerant with low global warming potential. Inhalation studies on HFO-1123 in rats indicated a low potential for toxicity (NOAELs ≥ 20,000 ppm). In contrast, single inhalation exposure of Goettingen® minipigs (≥ 500 ppm) and New Zealand white rabbits (≥ 1250 ppm) resulted in severe toxicity. It has been suggested that these pronounced species-differences in toxicity may be attributable to species-differences in biotransformation of HFO-1123 via the mercapturic acid pathway. Therefore, the overall objective of this study was to evaluate species-differences in glutathione (GSH) dependent in vitro metabolism of HFO-1123 in susceptible versus less susceptible species and humans as a basis for human risk assessment. Biotransformation of HFO-1123 to S-(1,1,2-trifluoroethyl)-L-glutathione (1123-GSH) and subsequent cysteine S-conjugate β-lyase-mediated cleavage of the corresponding cysteine conjugate (1123-CYS) was monitored in hepatic and renal subcellular fractions of mice, rats, minipigs, rabbits, and humans. While 1123-GSH formation occurred at higher rates in rat and rabbit liver S9 compared to minipig and human S9, increased β-lyase cleavage of 1123-CYS was observed in minipig kidney cytosol as compared to cytosolic fractions of other species. Increased β-lyase activity in minipig cytosol was accompanied by time-dependent formation of monofluoroacetic acid (MFA), a highly toxic compound that interferes with cellular energy production via inhibition of aconitase. Consistent with the significantly lower β-lyase activity in human cytosols, the intensity of the MFA signal in human cytosols was only a fraction of the signal obtained in minipig subcellular fractions. Even though the inconsistencies between GSH and β-lyase-dependent metabolism do not allow to draw a firm conclusion on the overall contribution of the mercapturic acid pathway to HFO-1123 biotransformation and toxicity in vivo, the β-lyase data suggest that humans may be less susceptible to HFO-1123 toxicity compared to minipigs.

Deep Learning Reconstruction to Improve the Quality of MR Imaging: Evaluating the Best Sequence for T-category Assessment in Non-small Cell Lung Cancer Patients

PURPOSE

Deep learning reconstruction (DLR) has been recommended as useful for improving image quality. Moreover, compressed sensing (CS) or DLR has been proposed as useful for improving temporal resolution and image quality on MR sequences in different body fields. However, there have been no reports regarding the utility of DLR for image quality and T-factor assessment improvements on T2-weighted imaging (T2WI), short inversion time (TI) inversion recovery (STIR) imaging, and unenhanced- and contrast-enhanced (CE) 3D fast spoiled gradient echo (GRE) imaging with and without CS in comparison with thin-section multidetector-row CT (MDCT) for non-small cell lung cancer (NSCLC) patients. The purpose of this study was to determine the utility of DLR for improving image quality and the appropriate sequence for T-category assessment for NSCLC patients.

METHODS

As subjects for this study, 213 pathologically diagnosed NSCLC patients who underwent thin-section MDCT and MR imaging as well as T-factor diagnosis were retrospectively enrolled. SNR of each tumor was calculated and compared by paired t-test for each sequence with and without DLR. T-factor for each patient was assessed with thin-section MDCT and all MR sequences, and the accuracy for T-factor diagnosis was compared among all sequences and thin-section CT by means of McNemar's test.

RESULTS

SNRs of T2WI, STIR imaging, unenhanced thin-section Quick 3D imaging, and CE-thin-section Quick 3D imaging with DLR were significantly higher than SNRs of those without DLR (P < 0.05). Diagnostic accuracy of STIR imaging and CE-thick- or thin-section Quick 3D imaging was significantly higher than that of thin-section CT, T2WI, and unenhanced thick- or thin-section Quick 3D imaging (P < 0.05).

CONCLUSION

DLR is thus considered useful for image quality improvement on MR imaging. STIR imaging and CE-Quick 3D imaging with or without CS were validated as appropriate MR sequences for T-factor evaluation in NSCLC patients.

Reverse encoding distortion correction for diffusion-weighted MRI: Efficacy for improving image quality and ADC evaluation for differentiating malignant from benign areas in suspected prostatic cancer patients

PURPOSE

The purpose of this study was to determine the influenceof reverse encoding distortion correction (RDC) on ADC measurement and its efficacy for improving image quality and diagnostic performance for differentiating malignant from benign prostatic areas on prostatic DWI.

METHODS

Forty suspected prostatic cancer patients underwent DWI with or without RDC (i.e. RDC DWI or DWI) using a 3 T MR system as well as pathological examinations. The pathological examination results indicated 86 areas were malignant while 86 out of 394 areas were computationally selected as benign. SNR for benign areas and muscle and ADCs for malignant and benign areas were determined by ROI measurements on each DWI. Moreover, overall image quality was assessed with a 5-point visual scoring system on each DWI. Paired t-test or Wilcoxon's signed rank test was performed to compare SNR and overall image quality for DWIs. ROC analysis was then used to compare the diagnostic performance, and sensitivity (SE), specificity (SP) and accuracy (AC) of ADC were compared between two DWI by means of McNemar's test.

RESULTS

SNR and overall image quality of RDC DWI showed significant improvements when compared with those of DWI (p < 0.05). Areas under the curve (AUC), SP and AC of DWI RDC DWI (AUC: 0.85, SP: 72.1%, AC: 79.1%) were significantly better than those of DWI (AUC: 0.79, p = 0.008; SP: 64%, p = 0.02; AC: 74.4%, p = 0.008).

CONCLUSION

RDC technique has the potential to improve image quality and ability to differentiate malignant from benign prostatic areas on DWIs of suspected prostatic cancer patients.

Prediction of difficulty in cryoballoon ablation with a 3D deep learning model using polygonal mesh representation

Background

Cryoballoon ablation (CBA) is a useful treatment for pulmonary vein isolation (PVI). Some cases, however, are difficult to treat and may require multiple freezing procedures and/or touch-up ablation. Although several predictors of CBA difficulty have been reported, no report has been able to assess the spatial location and morphology of the left atrium (LA) and pulmonary veins (PVs). A polygonal mesh is a collection of vertices, edges, and faces that defines the shape of a polyhedral object, and is able to represent a spatial location with a small amount of information. We hypothesized that a deep learning model that learns mesh representation datasets could more accurately detect the CBA difficulty and that we could establish a novel evaluation method in CBA.

Purpose

The aim of this study was to create a model to predict CBA difficulty with a 3D deep learning model using polygonal mesh representation.

Methods and results

All the 140 patients who underwent CBA for drug-resistant atrial fibrillation between January 2015 and January 2022 were included. A 28-mm cryoballoon (Arctic Front Advance, Medtronic) was used in all cases. We defined CBA difficulty as requiring a touch-up ablation procedure to create complete PVI. We converted the volume data in DICOM format of the computed tomography images of PVs and LA to obj file format (shown in Figure 1), which supports the definition of the geometry for object surfaces using polygonal meshes. Next, we developed a deep learning model that could learn polygonal meshes and classify whether the CBA required touch-up ablation or not. Only a training dataset is used to train the deep learning model, and finally, a test dataset is used to evaluate the model metrics. The accuracy, area under the ROC curve, recall, precision, and f1-score of the deep learning model using the test dataset was 86.5%, 87.7%, 66.7%, 75.0%, 70.6%, respectively.

Conclusions

We developed a 3D deep learning model that can detect a difficulty in CBA using polygonal mesh representation. By predicting difficult cases in advance, we will be able to develop strategies to increase the success rate.

Funding Acknowledgement

Type of funding sources: None.

Denosumab-related osteonecrosis of the jaw after tooth extraction and the effects of a short drug holiday in cancer patients: a multicenter retrospective study

Pre-existing inflammation, corticosteroid therapy, periapical periodontitis, longer duration of denosumab therapy, and female sex were significantly associated with an increased risk of denosumab-related osteonecrosis of the jaw after tooth extraction in patients with cancer on oncologic doses of denosumab. A short drug holiday did not protect against this complication.

INTRODUCTION

This study retrospectively investigated the relationship between various risk factors, including brief discontinuation of denosumab, and development of denosumab-related osteonecrosis of the jaw (DRONJ) after tooth extraction in patients with cancer who were receiving oncologic doses of this agent.

METHODS

Data were collected on demographic characteristics, duration of denosumab therapy, whether or not denosumab was discontinued before tooth extraction (drug holiday), duration of discontinuation, presence of pre-existing inflammation, and whether or not additional surgical procedures were performed. Risk factors for DRONJ after tooth extraction were evaluated by univariate and multivariate analyses.

RESULTS

A total of 136 dental extractions were performed in 72 patients (31 men, 41 women) with cancer who were receiving oncologic doses of denosumab. Post-extraction DRONJ was diagnosed in 39 teeth (28.7%) in 25 patients. Tooth extraction was significantly associated with development of DRONJ only in patients with pre-existing inflammation (odds ratio [OR] 243.77), those on corticosteroid therapy (OR 73.50), those with periapical periodontitis (OR 14.13), those who had been taking oncologic doses of denosumab for a longer period (OR 4.69), and in women (OR 1.04). There was no significant difference in the occurrence of DRONJ between patients who had a drug holiday before tooth extraction and those who did not.

CONCLUSIONS

These findings suggest that inflamed teeth should be extracted immediately in patients with cancer who are receiving oncologic doses of denosumab. Drug holidays have no significant impact on the risk of DRONJ.

Significance of mitral L wave to predict late recurrence of atrial fibrillation after radiofrequency catheter ablation

Background

Mitral L wave, prominent mid-diastolic filling wave in echocardiographic examinations, is associated with severe left ventricular diastolic dysfunction, and that has been reported to predict recurrent atrial fibrillation (AF) after cardioversion. However, association between mitral L wave and the outcome of AF after radiofrequency catheter ablation (RFCA) has not been established.

Objective

The aim of this study is to evaluate the predictive value of mitral L wave on AF recurrence after RFCA.

Methods

250 patients including 164 paroxysmal AF (65.6%) and 86 non-paroxysmal AF (34.4%) who received RFCA in single center from January 2015 to December 2016 were enrolled consecutively. Echocardiographic examinations before RFCA were recorded, and the mitral L wave was defined as a distinct mid-diastolic flow velocity with a peak velocity ≥20 cm/s following the E wave. Systematic follow-up was conducted after RFCA. Univariate and multivariate analyses were carried out to determine the factors predicting late recurrence of AF (LRAF) which means AF recurrence after 3 months. Enrolled patients were divided into groups with the L wave (L-group; n=57) or without the L wave (NL-group; n=193) based on the findings of echocardiographic examinations.

Results

During a follow-up of 35.0±17.6 months, the ratio of LRAF in the L-group was significantly higher than that in the NL-group (32 (56.1%) vs. 41 (21.2%), Hazard ratio [HR]: 3.55, 95% confidence interval [CI]: 2.33 - 5.42, p&lt;0.001). Among the clinical factors, presence of mitral L wave, BNP value, non-paroxysmal AF and moderate-severe mitral regurgitation were related to LRAF. A multivariate analysis using a Cox proportional hazard model found that presence of mitral L wave (HR: 2.67, 95% CI: 1.30 - 5.48, p=0.007) was significantly associated with LRAF.

Conclusion

This study revealed that mitral L wave predicts late recurrence of AF after RFCA.

Funding Acknowledgement

Type of funding sources: None.

Electrocardiographic evaluation of depolarization and repolarization abnormalities in breast cancer patients with HER2-inhibitor related cardiac dysfunction

Background

The arrhythmic substrates of the myocardium such as depolarization and repolarization abnormalities are thought to reflect cardiac dysfunction prior to the morphologic left ventricular dysfunction. Activation time (AT), recovery time (RT) and T wave peek-end interval dispersion (Tpe-dispersion) are useful indicators of the arrhythmic substrate. We examined the appearance of depolarization and repolarization abnormalities in patients with cancer therapeutics-related cardiac dysfunction (CTRCD) using AT, RT and Tpe-dispersion.

Methods

We conducted a standardized case-control study of CTRCD with 40 patients who developed breast cancer and treated with trastuzumab (13 cases and 27 controls). We assessed the relation between electrocardiographic indexes, including AT, RT and corrected Tpe-dispersion, and CTRCD. QT intervals were measured by Fridericia method, and QT observer 3 software were used for the measurement of all electrocardiographic indexes.

Results

LVEF in case and control group were 45.7±8% and 69.2±6%, respectively. AT in aVR lead was significantly higher in case group compared with control (28.8±7ms vs 22.8±5ms, P=0.02). corrected Tpe-dispersion tended to be higher in case group than that of control group (43.2±19ms vs 31.9±10ms, P=0.06). QT dispersion and RT dispersion were not different between case and control group.

Conclusions

Our study demonstrated that AT in aVR may predict cardiac dysfunction in breast cancer patients with HER2-inhibitor related cardiac dysfunction. More detailed studies using other modalities which can detect depolarization and repolarization abnormalities, including ventricular late potentials and T wave alternans, are needed.

Funding Acknowledgement

Type of funding source: None

FRI0129 DEVELOPMENT OF A PREDICTION MODEL FOR MAXIMUM METHOTREXATE (MTX) DOSE WITHOUT HEPATOTOXICITY USING AN INDEX OF ERYTHROCYTE MTX-POLYGLUTAMATE (MTXPG) LEVELS SPECULATED BY CLINICAL AND GENETIC MARKERS

Background:

MTX is transported into cells and retained long after polyglutamation. MTXPG level can predict response and possibly adverse effects of MTX. We reported erythrocyte MTXPG concentrations efficiently discriminated patients with and without hepatotoxicity1. We also developed genetic and clinical prediction models for efficacy and hepatotoxicity of MTX2. In the present study, we firstly investigated the effects of clinical and secondly genetic variables on the concentration of total MTXPG and determined oral maximum MTX dose without hepatotoxicity using these variables.

Objectives:

To develop a prediction model for maximum MTX dose without hepatotoxicity.

Methods:

Concentrations of erythrocyte MTX-PG (PG1 to PG4) were detected by LC-MS/MS and calculated total MTXPG as sum of them. MTX-PGn levels were measured in 265 RA patients including 40 patients with elevated AST or ALT (≥ 60 U/L; 1.5 times of upper limits) and the 6 SNPs of 6 gens related to MTXPG metabolism were identified by RT-PCR.

Results:

Total concentrations of MTXPG were 141.3 ± 86.5 and 87.6 ± 47.8 nmol/L (mean±SD) in 40 RA patients with hepatotoxicity and 225 patients without, respectively (p<0.0001). By ROC analysis, the two groups were most efficiently discriminated with cutoff concentration of 100.0 nmol/L (AUC 0.731). Next, genetic and clinical model to speculate the MTXPG concentration was established by multivariate analysis using 4 clinical and 3 genetic variables which were selected from 20 clinical and 6 genetic variables by univariate analysis (p<0.1). Finally, a speculation model for MTXPG concentration by 4 clinical variables (MTX dose, BMI, RBC count, and creatinine) and one genetic variable (GGH c.452C>T) was developed (Figure). When MTXPG concentration of 100 nmol/L was applied to the model, maximum MTX dose without hepatotoxicity was calculated for each patient asMTX dose (mg) = {100 (MTXPG) – 96 + 1.7*BMI + 28*RBC - 120*creatinine - 19.3*GGH(C/T)} / 7.7. Real dose of oral MTX exceeded the calculated dose in 23 of 40 patients (57.5%) with hepatotoxicity, whereas it exceeded in 95 of 223 patients (42.6%) without hepatotoxicity (OR 1.82, p=0.081).

Conclusion:

Maximum MTX dose without hepatotoxicity was speculated by several clinical and genetic markers without measurement of erythrocyte MTX-PG concentrations.

References:

[1]Takahashi M, et al: Clinical Pathology (Rinsho Byori), 67:433-442, 2019.

[2]Onishi A, et al: The Pharmacogenomics J, doi.org/10.1038/s41397-019-0134-9, 2019

Disclosure of Interests:

Shunichi Kumagai Grant/research support from: Astellas, Chugai, Mitsubishi Tanabe Co.Ltds, Consultant of: Sysmex Co.Ltd, Speakers bureau: many companies, Soshi Takahashi: None declared, Miho Takahashi: None declared, Toshiharu Saito: None declared, Katsuyuki Yoshida: None declared, Motoko Katayama: None declared, Saki Mukohara: None declared, Norihiko Amano: None declared, Akira Onishi Speakers bureau: AO received a speaker fee from Chugai, Ono Pharmaceutical, Eli Lilly, Mitsubishi-Tanabe, Asahi-Kasei, and Takeda, Masakazu Shinohara: None declared, Saori Hatachi: None declared

P93 The usefulness of dual cardiac autonomic nervous modulation assessment for prediction of mortality in patients with relatively preserved left ventricular ejection fraction

Background

Recent guidelines have stated that reduced left ventricular ejection fraction (LVEF) is the gold standard marker for identifying patients at risk for cardiac mortality. Although reduced LVEF identifies patients at an increased risk of cardiac arrest, sudden cardiac deaths (SCDs) occur considerably more often in patients with relatively preserved LVEF. Current guidelines on SCDs risk stratification do not adequately cover this general population pool. Heart rate variability (HRV) and heart rate turbulence (HRT) are non-invasive electrocardiography (ECG)-based techniques capable of providing relevant information on the cardiac autonomic nervous modulation. Although a large body of evidence about autonomic nervous modulation markers has been reported, the usefulness of HRV and HRT parameters for risk stratification in such patients with relatively preserved LVEF has not yet been elucidated.

Purpose

This study aimed to evaluate HRV and HRT parameters for predicting cardiac mortality in patients with structural heart disease (SHD), including ischemic heart disease, dilated cardiomyopathy and valvular heart disease, who have mid-range left ventricular dysfunction (LVD).

Methods

We prospectively enrolled 229 patients (187 men, age 63 ± 13 years) with SHD who have mid-range LVD (LVEF &gt; 40%). HRV and HRT parameters based on 24-hour ambulatory ECG recordings (Fukuda Denshi Co., Ltd., Tokyo, Japan) were evaluated as follows; SDNN, triangular index, high and low frequency HRV, turbulence onset and slope. The primary endpoint was all-cause mortality. Univariate and multivariate Cox regression analysis were used to assess the association between these cardiac autonomic nervous modulation and mortality.

Results

During a mean follow-up of 21 ± 11 months, all-cause mortality was seen in 11 (4.8%) patients. Univariate Cox regression analysis showed that reduced SDNN (&lt;50ms), reduced triangular index (&lt;20ms) and HRT category 2 were significantly associated with the primary endpoint (P &lt; 0.05). When HRT category 2 combined with reduced SDNN, Multivariate Cox regression analysis revealed that this combination more strongly associates with the primary endpoint (hazard ratio =7.91, 95%CI, 1.82-34.2; P = 0.006).

Conclusion

Dual cardiac autonomic nervous modulation assessment which combined HRT and HRV could be a superior technique to predict mortality in patients with relatively preserved LVEF.

P3754Comparison of the transdermal bisoprolol patch with the oral bisoprolol fumarate administration as a therapeutic agent for idiopathic frequent premature ventricular contractions

Background

The transdermal bisoprolol patch (TB) was designed to maintain a sustained concentration of bisoprolol in plasma by higher trough concentration than the oral bisoporolol fumarate administration (OB). It is unclear whether the TB is as effective in treating idiopathic premature ventricular contractions (PVCs) as the OB.

Purpose

We compared the efficacy between the TB and OB in treating idiopathic PVCs while considering their duration of action.

Methods

Among 198 patients with a PVC count of ≥3,000 beats/24 hours, 84 patients were divided into groups treated with TB 4mg (n=50) or OB 2.5mg (n=34). The PVCs were divided into positive heart rate (HR)-dependent PVCs (P-PVCs) and non-positive HR-dependent PVCs (NP-PVCs) based on the relationship between the hourly PVCs density and hourly mean HR. To evaluate the efficacy, PVC counts by 24-hour Holter electrocardiograms were measured at baseline and at 1 month after the initiation of the therapy.

Results

There were no significant between-group differences for the mean HR, PVC count, or type of PVCs. Both the TB (from 16,692±9,737 to 10,442±10,711 beats/24 hours, P<0.001) and OB (from 19,633±16,298 to 9,235±12,124 beats/24 hours, P<0.001) significantly decreased the total PVC count after the initiation of therapy, and a comparison between the two drugs showed no significant difference (P=0.46). In the P-PVC group, both the TB and OB significantly decreased the total PVC count (P<0.001, P=0.022 respectively), PVC count during the day-time (P<0.001, P=0.030 respectively), and PVC count during the night-time (P=0.0038, P=0.022 respectively). In contrast, in the NP-PVC group, neither the TB nor OB made any significantly change in the total PVC count (P=0.079, P=0.10 respectively), PVC count during the day-time (P=0.35, P=0.12 respectively), or PVC count during the night-time (P=0.11, P=0.12 respectively). The TB exhibited a significant reduction during each time period regarding the changes within 24-hours in the P-PVC count from baseline, while the OB did not significantly reduce the P-PVC count from baseline during each time period between 0 and 5 o'clock.

Conclusions

Compared with the OB, the TB could be used with the same efficacy for reducing the PVC count. The TB could be a more useful therapeutic agent for idiopathic P-PVCs during a 24-hour period than the OB.

P6559Long-term follow-up and outcomes of patients with discontinuation of oral anticoagulant therapy after successful ablation procedures for atrial fibrillation

Background

Oral anticoagulant therapy (OAT) is effective for preventing strokes in atrial fibrillation (AF) patients. Currently, there is controversy regarding the discontinuation of OATs in patients with ablation procedures to eliminate AF.

Aim

We investigated the incidence of major bleeding and ischemic strokes/systemic embolisms in low-risk patients that discontinued OATs after successful AF ablation procedures.

Methods

Of 330 consecutive patients that underwent AF ablation procedures and were prescribed one of the direct oral anticoagulants or warfarin, 207 AF patients (158 men, mean age 61±11 years) who discontinued OATs three months after the procedure were enrolled. The average CHADS2 and HAS-BLED scores were 1.0±0.9 and 1.2±1.0, respectively, which meant that most patients had a low risk for strokes.

Results

During follow-up, 31 patients (15%) had recurrences of AF. Those patients underwent a re-ablation procedure and then re-discontinued their OATs three months after the session. During a 60±13 months follow-up, major bleeding was observed in five patients (2.4%) and was associated with a higher HAS-BLED score (2.2±0.4 vs. 1.1±1.0, P=0.027). In contrast, none of the patients experienced ischemic strokes/systemic embolisms.

Conclusions

This prospective study demonstrated that in patients with successful ablation procedures and low risk scores for AF management, OATs could be discontinued three months after the procedure. Unnecessary continuation of OATs may increase the incidence of major bleeding during the follow-up.

Mechanical regulation of bone homeostasis through p130Cas-mediated alleviation of NF-κB activity

Mechanical loading plays an important role in bone homeostasis. However, molecular mechanisms behind the mechanical regulation of bone homeostasis are poorly understood. We previously reported p130Cas (Cas) as a key molecule in cellular mechanosensing at focal adhesions. Here, we demonstrate that Cas is distributed in the nucleus and supports mechanical loading-mediated bone homeostasis by alleviating NF-κB activity, which would otherwise prompt inflammatory processes. Mechanical unloading modulates Cas distribution and NF-κB activity in osteocytes, the mechanosensory cells in bones. Cas deficiency in osteocytes increases osteoclastic bone resorption associated with NF-κB-mediated RANKL expression, leading to osteopenia. Upon shear stress application on cultured osteocytes, Cas translocates into the nucleus and down-regulates NF-κB activity. Collectively, fluid shear stress-dependent Cas-mediated alleviation of NF-κB activity supports bone homeostasis. Given the ubiquitous expression of Cas and NF-κB together with systemic distribution of interstitial fluid, the Cas-NF-κB interplay may also underpin regulatory mechanisms in other tissues and organs.

The Plasmin Heavy Chain - Urokinase Conjugate: A Specific Thrombolytic Agent

Low molecular weight urokinase (LMW-UK) was coupled to the heavy chain of plasmin to make it able to bind to fibrin. The purified conjugate (PHC-UK conjugate), which consisted of equimolar concentrations of each starting material had a molecular weight of 93,600, bound tightly to fibrin-monomer-Sepharose and was not washed off with 1 M NaCl, but was eluted specifically with s-amino caproic acid. The conjugate showed higher fibrinolytic activity than HMW-UK. A control conjugate prepared by coupling human serum albumin to LMW-UK (HSA-UK conjugate) showed the same fibrinolytic activity as HMW-UK. The half-lives of these two conjugates in rabbits were about 3 times that of HMW-UK. In an experimental pulmonary embolism model in rabbits, the PHC-UK conjugate showed about 10 times higher thrombolytic activity than HMW-UK, while the HSA-UK conjugate showed similar thrombolytic activity as HMW-UK, and moreover caused severe systemic fibrinogen breakdown. Thus the significant increase in thrombolytic activity after injection of PHC-UK conjugate into rabbits may be due to its newly acquired fibrin binding activity, and not to increase in its half-life. It is concluded that the PHC-UK conjugate may be useful in treatment of thrombosis.

Novel integrative methodology for engineering large liver tissue equivalents based on three-dimensional scaffold fabrication and cellular aggregate assembly

A novel engineering methodology for organizing a large liver tissue equivalent was established by intergrating both 'top down' and 'bottom up' approaches. A three-dimensional (3D) scaffold was engineered comprising 43 culture chambers (volume: 11.63 cm(3)) assembled in a symmetrical pattern on 3 layers, a design which enables further scaling up of the device to a clinically significant size (volume: 500 cm(3)). In addition, an inter-connected flow channel network was designed and proved to homogenously deliver culture medium to each chamber with the same pressure drop. After fabrication using nylon-12 and a selective laser sintering process, co-cultured cellular aggregates of human hepatoma Hep G2 and TMNK-1 cells were loosely packed into the culture chambers with biodegradable poly-L-lactic acid fibre pieces for 9 days of perfusion culture. The device enabled increased hepatic function and well-maintained cell viability, demonstrating the importance of an independent medium flow supply for cell growth and function provided by the current 3D scaffold. This integrative methodology from the macro- to the micro-scale provides an efficient way of arranging engineered liver tissue with improved mass transfer, making it possible to further scale up to a construct with clinically relevant size while maintaining high per-volume-based physiological function in the near future.

Significant Reduction of the Echogenicity of the Compressed Cavernous Hemangioma

Eleven hyperreflective hepatic nodules in eight patients were examined by means of intraoperative ultrasonography (US) with the transducer placed on the liver surface. The nodules included four cavernous hemangiomas, four hepatocellular carcinomas, one metastatic tumor, and two regenerative nodules in cirrhotic livers. When the relevant part of the liver was compressed during US observation, the echogenicity was reduced only in the case of cavernous hemangioma. This phenomenon is considered to be unique to cavernous hemangioma.

Genetic analyses of GII.17 norovirus strains in diarrheal disease outbreaks from December 2014 to March 2015 in Japan reveal a novel polymerase sequence and amino acid substitutions in the capsid region

A novel GII.P17-GII.17 variant norovirus emerged as a major cause of norovirus outbreaks from December 2014 to March 2015 in Japan. Named Hu/GII/JP/2014/GII.P17-GII.17, this variant has a newly identified GII.P17 type RNA-dependent RNA polymerase, while the capsid sequence displays amino acid substitutions around histo-blood group antigen (HBGA) binding sites. Several variants caused by mutations in the capsid region have previously been observed in the GII.4 genotype. Monitoring the GII.17 variant's geographical spread and evolution is important.

[Evaluation of the right internal iliac artery which is anastomosed to transplant renal artery using non-contrast enhanced MR angiography with electrocardiography-gated and 3D True SSFP time-spatial labeling inversion pulse sequence]

To evaluate whether electrocardiography-gated is useful in non-contrast-enhanced MRA with time-spatial labeling inversion pulse (Time-SLIP) in renal transplantation patients compared with respiration-triggered free-breathing. Simulation-based analyses of black blood time interval (BBTI) values for spatial selective inversion-recovery pulse and electrocardiography rates were performed, and confirmed on human subjects using a three-dimensional (3D) coherent steady-state free precession (SSFP) sequence on a 1.5 tesla Toshiba MRI scanner. Signal acquisition interval and BBTI values in which signal of a water tissue becomes the null point showed a strong correlation, and successfully suppressed signals from the background and provided better contrast between the arteries and the background. Because electrocardiography-gated non-contrast MRA does not depend on the respiration interval, providing a contrast stable, it was suggested to be an effective screening tool for evaluation of pelvic arteries.

A drug formulation using an alginate hydrogel matrix for efficient oral delivery of the manganese porphyrin-based superoxide dismutase mimic

In order for patients to avail of the therapeutic benefits of antioxidant drugs efficiently and conveniently, a robust oral delivery system needs to be developed.

[Optimal imaging parameters and the advantage of cerebrospinal fluid flow image using time-spatial labeling inversion pulse at 3 tesla magnetic resonance imaging: comparison of image quality for 1.5 tesla magnetic resonance imaging]

Cerebrospinal fluid (CSF) imaging by time-spatial labeling inversion pulse (Time-SLIP) technique is labeled by CSF with a selective inversion recovery (IR) pulse as internal tracer, thus making it possible to visualize CSF dynamics non-invasively. The purpose of this study was to clarify labeled CSF signals during various black blood time to inversion (BBTI) values at 3 tesla (T) and 1.5 T magnetic resonance imaging (MRI) and to determine appropriate CSF imaging parameters at 3 T MRI in 10 healthy volunteers. To calculate optimal BBTI values, ROIs were set in untagged cerebral parenchyma and CSF on the image of the CSF flow from the aqueduct to the fourth ventricle in 1.5 T and 3 T MRI. Visual evaluation of CSF flow also was assessed with changes of matrix and echo time (TE) at 3 T MRI. The mean BBTI value at null point of untagged CSF in 3 T MRI was longer than that of 1.5 T. The MR conditions of the highest visual evaluation were FOV, 14 cm×14 cm; Matrix, 192×192; and TE, 117 ms. CSF imaging using Time-SLIP at 3 T MRI is expected visualization of CSF flow and clarification of CSF dynamics in more detail by setting the optimal conditions because 3 T MRI has the advantage of high contrast and high signal-to-noise ratio.

Angiosarcoma of the oral cavity: a clinicopathological study and a review of the literature

Soft tissue sarcomas are uncommon in the head and neck. Primary angiosarcomas of the oral cavity area are extremely rare, and have mostly been presented as case reports. This paper presents the clinical and histological features of three such cases. All patients were diagnosed based on the presence of rapidly extending masses involving the tongue, maxillary gingiva, or mandibular gingiva; bone destruction was present in two cases. The resected specimens revealed clustered large, pleomorphic, and spindle-shaped cells with a markedly haemorrhagic background. Tumour cells showed expression of vascular endothelial markers, such a CD31, CD34, and factor VIII-related antigen. Despite undergoing radical surgery, distant metastases developed in all three cases. We also studied the clinicopathological features of a series of oral angiosarcomas. This article therefore reports the clinicopathological features of the three new cases and provides a review of the cases of primary oral angiosarcoma reported during the past 20 years.

Acute decrease in the stiffness of resting muscle belly due to static stretching

The purpose of the study was to examine the acute effect of static stretching exercise on the resting stiffness of gastrocnemius muscle belly. Ten healthy young adults performed standing wall stretching in dorsiflexion for 1 min at a time and repeated five times. Before and after stretching, the shear modulus was measured in medial and lateral heads of the resting gastrocnemius muscle with ultrasound shear-wave elastography. After the stretching, dorsiflexion range of motion (ROM) of the ankle joint increased (P < 0.01) by 3.9° and returned in 20 min. Immediately after stretching, shear modulus decreased (P < 0.01) by 14%, compared with before stretching across muscle heads. The decrease in shear modulus returned in 20 min after stretching. In the comparison group of 10 additional subjects, the standing intervention without stretching had no influence on these measures. There was a negative correlation between dorsiflexion ROM and shear modulus in either head before and after stretching. The results demonstrate the transient decreases in the stiffness of the resting gastrocnemius muscle belly and indicate that joint flexibility is greater in individuals with lower resting stiffness of the muscle belly.

Transumbilical laparoscopic surgery using GelPort through an umbilical zigzag skin incision

INTRODUCTION

We report herein a new method of transumbilical laparoscopic surgery using a GelPort through an umbilical zigzag skin incision. The method involves collaborating with plastic surgeons to ensure the procedure was minimally invasive.

MATERIALS AND SURGICAL TECHNIQUE

After marking a zigzag skin incision in the umbilical region, the skin was incised along this line. Then, a GelPort double-ring wound retractor was inserted through the incision, which enlarged the diameter of the fascial opening to 6 cm. The Gelport was latched on the wound retractor ring, following the inflation of the pneumoperitoneum by CO (2). One or more additional ports were inserted as necessary. All operations were performed in the standard fashion. The specimen was easily extracted from the abdomen through the umbilical incision, and anastomosis was performed. Using the above method, we performed the following procedures: one total gastrectomy, one distal gastrectomy, three gastric local resections, five right hemicolectomies, two high anterior resections, three cholecystectomies, and seven transabdominal preperitoneal hernioplasties. All cases were accomplished without any complications using this method. The wounds of the umbilical region were almost "scarless" in all cases.

DISCUSSION

We developed an umbilical zigzag skin incision technique to perform abdominal laparoscopic operations using a GelPort, with a minimal number of skin incisions. We consider that our method reduces the technical difficulties associated with laparoscopic surgery and maintains cosmesis.