Modulation of pain perception through transcranial alternating current stimulation and its nonlinear relationship with the simulated electric field magnitude

BACKGROUND

Oscillatory activities observed in multiple regions are closely associated with the experience of pain. Specifically, oscillatory activities within the theta- and beta-frequency bands, observed in the left dorsolateral prefrontal cortex (DLPFC), have been implicated in pain perception among healthy individuals and those with chronic pain. However, their physiological significance remains unclear.

METHODS

We explored the modulation of pain perception in healthy individuals by theta- and beta-band transcranial alternating current stimulation (tACS) over the left DLPFC and examined the relationship between the modulation effect and magnitude of the electric field elicited by tACS in the left DLPFC using computational simulation.

RESULTS

Our findings revealed that both theta- and beta-tACS increased the heat pain threshold during and after stimulation. Notably, the simulated electric field magnitude in the left DLPFC exhibited an inverted U-shaped relationship with the pain modulation effect for theta-tACS.

CONCLUSIONS

Our study findings suggested that there would be an optimal electric field strength to produce a high analgesic effect for theta-tACS.

SIGNIFICANCE

The application of theta- and beta-tACS interventions targeting the left DLPFC might facilitate the treatment of chronic pain. Furthermore, the attainment of effective pain modulation via theta-tACS over the DLPFC warrants the use of optimal stimulus intensity.

5-Year Renal Function Outcomes after SABR for Primary Renal Cell Carcinoma: A Report from the International Radiosurgery Oncology Consortium of the Kidney (IROCK)

PURPOSE/OBJECTIVE(S)

Renal cell carcinoma (RCC) presents uncommonly in patients with a congenital solitary kidney or prior contralateral nephrectomy. The objective of this study was to compare renal function outcomes of stereotactic ablative body radiotherapy (SABR) in patients with solitary vs. bilateral kidneys.

MATERIALS/METHODS

Patients with primary RCC with ≥2 years of follow-up at 12 participating International Radiosurgery Consortium for Kidney (IROCK) institutions were included. Patients with upper tract urothelial carcinoma or metastatic disease were excluded. Renal function was measured by estimated glomerular filtration rate (eGFR). For patients where eGFR was not recorded, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate eGFR based on known creatinine. Baseline characteristics and renal function outcomes were compared between solitary vs. bilateral kidneys. Multivariable logistic regression was used to identify factors predictive of eGFR decline ≥ 15 mL/min and any eGFR increase evaluated at 1-year post-SABR.

RESULTS

One hundred and ninety patients with solitary (n = 56) or bilateral kidneys (n = 134) underwent SABR and were followed for a median of 5.0 years (IQR: 3.4-6.8). Pre-SABR eGFR (mean ± SD) was similar in patients with solitary (61.1 ± 23.2 mL/min) vs. bilateral kidneys (58.0 ± 22.3 mL/min, p = 0.324). Mean tumor size was 3.70 ± 1.40 cm in solitary and 4.35 ± 2.50 cm in bilateral kidneys (p = 0.026). After SABR, an initial compensatory increase in eGFR was observed in both cohorts (22.7% solitary and 17.7% bilateral at 1 year). This compensatory increase persisted in patients with bilateral but not a solitary kidney (10.3% vs. 0% at 3-years and 21.1% vs. 0% at 5-years, respectively). At 5-years post-SABR, eGFR decreased by -14.5 ± 7.6 in solitary and -13.3 ± 15.9 mL/min in bilateral kidneys (p = 0.665). At all timepoints assessed, there were no significant differences in eGFR decline between solitary vs. bilateral cohorts (all p > 0.05). There were also no significant differences in post-SABR end-stage renal disease (7.1% vs. 6.7%) or dialysis (3.6% vs. 3.7%) in solitary vs. bilateral, respectively. Multivariable analysis demonstrated that increasing tumor size (OR per 1 cm: 1.57; 95% CI: 1.14-2.16, p = 0.006) and baseline eGFR (OR per 10 mL/min: 1.30; 95% CI: 1.02-1.66, p = 0.034) was more likely to be associated with eGFR decline ≥ 15 mL/min. There was no significant association between solitary vs. bilateral kidney and eGFR decline (OR: 1.22; 95% CI: 0.45-3.34, p = 0.693).

CONCLUSION

There was no observed difference between renal function outcomes in patients with a solitary vs. bilateral kidneys. While larger tumor size may increase the risk of eGFR decline post-SABR, treatment of a solitary kidney does not appear to increase the risk of renal dysfunction long-term.

Quality of Palliative Radiation Therapy Assessed Using Quality Indicators: A Multicenter Survey

PURPOSE/OBJECTIVE(S)

Clinical practice is not always performed in accordance with guideline recommendations. Quality indicators (QIs) are valuable tools for evaluating the quality of healthcare systems. We sought to identify potential gaps between clinical practice and evidence using QIs previously developed using a modified Delphi method.

MATERIALS/METHODS

We used seven QIs (Table 1) to assess the quality of radiation therapy for bone (BoM) and brain metastases (BrM) at 29 centers; 13 (45%) were academic (12 university hospitals and 1 cancer center) and 16 (55%) were nonacademic hospitals. Compliance rate was calculated as the percentage of patients for whom recommended medical care was conducted. Random effects models were used to estimate pooled compliance rates. Mixed effects models with a Q test were used to compare compliance rates between academic and nonacademic centers.

RESULTS

The estimates of the compliance rates with 95% confidence intervals are presented in Table 1. For BoM-1, the compliance rate was higher in academic hospitals (100% [100-100%]) than in non-academic hospitals (96% [89-100%]) (P = 0.021). For BrM-3, the compliance rate was lower in academic hospitals (92% [81-99%]) than in nonacademic hospitals (100% [98-100%]) (P = 0.016).

CONCLUSION

A quality assessment based on these seven QIs is feasible. Overall, compliance rates were high; however, for BoM-3, the practice remains to be improved in some centers. Based on BoM-4 compliance rates, steroids are infrequently used concurrently with radiation therapy for malignant spinal cord compression. Extended fractionation for BoM was less frequently performed in academic than in nonacademic centers. The initiation of radiation therapy for brain metastases was more frequently delayed in academic than in nonacademic centers.

Extracellular volume fraction using contrast-enhanced CT is useful in differentiating intrahepatic cholangiocellular carcinoma from hepatocellular carcinoma

Objectives

To evaluate whether tumor extracellular volume fraction (fECV) on contrast-enhanced computed tomography (CT) aids in the differentiation between intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC).

Methods

In this retrospective study, 113 patients with pathologically confirmed ICC (n = 39) or HCC (n = 74) who had undergone preoperative contrast-enhanced CT were enrolled. Enhancement values of the tumor (Etumor) and aorta (Eaorta) were obtained in the precontrast and equilibrium phase CT images. fECV was calculated using the following equation: fECV [%] = Etumor/Eaorta × (100 - hematocrit [%]). fECV values were compared between the ICC and HCC groups using Welch's t-test. The diagnostic performance of fECV for differentiating ICC and HCC was assessed using receiver-operating characteristic (ROC) analysis. fECV and the CT imaging features of tumors were evaluated by two radiologists. Multivariate logistic regression analysis was performed to identify factors predicting a diagnosis of ICC.

Results

Mean fECV was significantly higher in ICCs (43.8% ± 13.2%) than that in HCCs (31.6% ± 9.0%, p < 0.001). The area under the curve for differentiating ICC from HCC was 0.763 when the cutoff value of fECV was 41.5%. The multivariate analysis identified fECV (unit OR: 1.10; 95% CI: 1.01-1.21; p < 0.05), peripheral rim enhancement during the arterial phase (OR: 17.0; 95% CI: 1.29-225; p < 0.05), and absence of washout pattern (OR: 235; 95% CI: 14.03-3933; p < 0.001) as independent CT features for differentiating between the two tumor types.

Conclusions

A high value of fECV, peripheral rim enhancement during the arterial phase, and absence of washout pattern were independent factors in the differentiation of ICC from HCC.

ATP and its metabolite adenosine cooperatively upregulate the antigen-presenting molecules on dendritic cells leading to IFN-γ production by T cells

Dendritic cells (DCs) present foreign antigens to T cells via the major histocompatibility complex (MHC), thereby inducing acquired immune responses. ATP accumulates at sites of inflammation or in tumor tissues, which triggers local inflammatory responses. However, it remains to be clarified how ATP modulates the functions of DCs. In this study, we investigated the effects of extracellular ATP on mouse bone marrow-derived dendritic cells (BMDCs), as well as the potential for subsequent T cell activation. We found that high concentrations of ATP (1 mM) upregulated the cell surface expression levels of MHC-I, MHC-II, and co-stimulatory molecules CD80 and CD86, but not those of co-inhibitory molecules PD-L1 and PD-L2 in BMDCs. Increased surface expression of MHC-I, MHC-II, CD80, and CD86 was inhibited by a pan-P2 receptor antagonist. In addition, the upregulation of MHC-I and MHC-II expression was inhibited by an adenosine P1 receptor antagonist and by inhibitors of CD39 and CD73, which metabolize ATP to adenosine. These results suggest that adenosine is required for the ATP-induced upregulation of MHC-I and MHC-II. In the mixed leukocyte reaction assay, ATP-stimulated BMDCs activated CD4 and CD8 T cells and induced interferon-gamma (IFN-γ) production by these T cells. Collectively, these results suggest that high concentrations of extracellular ATP upregulate the expression of antigen-presenting and co-stimulatory molecules but not that of co-inhibitory molecules in BMDCs. Cooperative stimulation of ATP and its metabolite adenosine was required for the upregulation of MHC-I and MHC-II. These ATP-stimulated BMDCs induced the activation of IFN-γ-producing T cells upon antigen presentation.

Relationship between Shear Stiffness Measured by MR Elastography and Perfusion Metrics Measured by Perfusion CT of Meningiomas

BACKGROUND AND PURPOSE

When managing meningiomas, intraoperative tumor consistency and histologic subtype are indispensable factors influencing operative strategy. The purposes of this study were the following: 1) to investigate the correlation between stiffness assessed with MR elastography and perfusion metrics from perfusion CT, 2) to evaluate whether MR elastography and perfusion CT could predict intraoperative tumor consistency, and 3) to explore the predictive value of stiffness and perfusion metrics in distinguishing among histologic subtypes of meningioma.

MATERIALS AND METHODS

Mean tumor stiffness and relative perfusion metrics (blood flow, blood volume, and MTT) were calculated (relative to normal brain tissue) for 14 patients with meningiomas who underwent MR elastography and perfusion CT before surgery (cohort 1). Intraoperative tumor consistency was graded by a neurosurgeon in 18 patients (cohort 2, comprising the 14 patients from cohort 1 plus 4 additional patients). The correlation between tumor stiffness and perfusion metrics was evaluated in cohort 1, as was the ability of perfusion metrics to predict intraoperative tumor consistency and discriminate histologic subtypes. Cohort 2 was analyzed for the ability of stiffness to determine intraoperative tumor consistency and histologic subtypes.

RESULTS

The relative MTT was inversely correlated with stiffness (P = .006). Tumor stiffness was positively correlated with intraoperative tumor consistency (P = .01), while perfusion metrics were not. Relative MTT significantly discriminated transitional meningioma from meningothelial meningioma (P = .04), while stiffness did not significantly differentiate any histologic subtypes.

CONCLUSIONS

In meningioma, tumor stiffness may be useful to predict intraoperative tumor consistency, while relative MTT may potentially correlate with tumor stiffness and differentiate transitional meningioma from meningothelial meningioma.

Pathological Analysis of Early Transplant Glomerulopathy in Renal Allografts Using Low-Vacuum Scanning Electron Microscopy

AIM

Low-vacuum scanning electron microscopy (LVSEM) has been reported to aid in diagnosis of renal biopsy. This study evaluated early transplant glomerulopathy in kidney transplant recipients using LVSEM.

METHODS

We selected 4 biopsies of cg0, 5 biopsies of cg1a, 5 biopsies of cg1b, and 4 biopsies of cg2 lesions that had been evaluated by light microscopy (LM) and transmission electron microscopy from recipients with acute/active or chronic, active antibody-mediated rejection (AABMR or CAABMR). Renal allograft paraffin sections (1 µm thickness) were stained with periodic acid-methenamine silver and observed using LVSEM. The cg score was based on the Banff classification. The parameter "percentage of duplicated capillary number" was calculated as follows: in 1 glomerulus with glomerular basement membrane (GBM) duplication, the total duplicated capillary number/the total number of capillaries ×100.

RESULTS

In all 4 biopsy specimens with AABMR showing cg0, LVSEM revealed GBM duplication not identified by LM. The average percentage of duplicated capillary number per glomerulus with GBM duplication was higher when observed by LVSEM than when observed by LM in all cg1b and cg2 biopsy specimens.

CONCLUSION

LVSEM revealed early GBM duplication in AABMR. Early GBM duplication might progress in the very early phase of AABMR. GBM duplication was more frequently detected by LVSEM than by LM in biopsy specimens with early chronic, active antibody mediated rejection. Thus, LVSEM may be useful in diagnosis of early transplant glomerulopathy.

The assessment of lung function and residual hypoxemia after balloon pulmonary angioplasty for patients with chronic thromboembolic hypertension

Background

It has been reported that balloon pulmonary angioplasty (BPA) could dramatically improve hemodynamics in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, some patients have shown poor response in oxygenation and lung function even after BPA. The aim of our study was to evaluate the efficacy of BPA using clinical indicators and to investigate lung function and residual hypoxemia.

Method

Consecutive 103 patients who underwent BPA from September 2011 to August 2018 were enrolled. We evaluated hemodynamics with right heart catheterization, respiratory function test, arterial blood gas examination, and exercise capacity with 6 minute-walk-distance (6MWD).

Result

At the median 12-month follow-up after the final BPA session, following examination findings were significantly improved. Mean pulmonary artery pressure (39.0±8.2mmHg, 23.2±8.4mmHg, p&lt;0.001), Pulmonary vascular resistance (782±378 dynes / sec / cm-5, 331±187 dynes / sec / cm-5, p&lt;0.001), 6 MWD (310±94 m, 363±119 m, p&lt;0.001), PaO2 (63.1±15.8 mmHg, 68.5±13.6 mmHg, p=0.044),%VC (88.5±17.1, 91±16.3, p=0.036). However, the following examination findings did not improve after BPA. Oxygen desaturation during 6MWD test (−11.9±6.3, 12±7.9, p=0.65), %DLCO (64.2 17.1, 61.3 16.8, p=0.147).

Conclusion

BPA could dramatically improve hemodynamics and exercise tolerance. However, arterial oxygenation was not normalized after BPA. Moreover, oxygen desaturation in exercise, and %DLCO were almost unchanged. These observations might suggest the remaining arteriopathy in capillary level of pulmonary artery, but further research is needed.

Funding Acknowledgement

Type of funding source: None

Microvasculopathy evaluated by dual-energy computed tomography in chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension

Background

It has been previously reported that poor subpleural perfusion (PSP) in dual-energy computed tomography (DE-CT) might suggest the microvasculopathy in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, it remains unclear whether pathological findings of microvasculopathy in CTEPH and pulmonary arterial hypertension (PAH) are equivalent. The aim is to evaluate the microvasculopathy in CTEPH and PAH by using clinical parameters and DE-CT.

Methods

We retrospectively reviewed PSP (defined as subpleural spaces either not or minimally perfused in all segments) of consecutive treatment-naïve 89 CTEPH patients and 20 PAH patients who underwent DECT from Feb. 2015 to Dec. 2019.

We also evaluated hemodynamic parameters and DE-CT parameters including quantitative evaluation of pulmonary blood volume (PBV) which was calculated as the average of entire lung iodine density.

Results

PSP was observed in 49.4% of patients in CTEPH group versus 5.0% in PAH group (p&lt;0.01).

There were no significant differences in hemodynamics and lung PBV between CTEPH group and PAH group (mean pulmonary arterial pressure; 36.4±10.4mmHg vs 38.3±8.5mmHg p=0.464, pulmonary vascular resistance; 700±388dyne*sec/cm5 vs 805±440 dyne*sec/cm5 p=0.288, lung PBV; 24.9±6.4 Hounsfield Unit vs 22.0±6.6 Hounsfield Unit p=0.06, respectively), however diffusing capacity for carbon monoxide (%DLCO/VA) was significantly lower (69.5±16.8% vs 45.7±23.7% p&lt;0.01) in PAH group.

Conclusion

PSP in DE-CT, which was observed more frequently in patients with CTEPH, might suggest the different mechanism of microvasculopathy from PAH in patients with CTEPH. Microvasculopathy in CTEPH would be diffuse very distal thrombosis. DE-CT is effective modality to detect microvasculopathy of diffuse distal thrombosis in patients with CTEPH.

DECT, Poor subpleural perfusion

Funding Acknowledgement

Type of funding source: None

Efficacy of interventional treatment for patients with chronic thromboembolic pulmonary hypertension with microvasculopathy

Background

The existence of microvasculopathy in chronic thromboembolic pulmonary hypertension (CTEPH) had been suggested. However, the impact of microvasculopathy for pathophysiology had been unknown. Recently dual-energy computed tomography (DECT) can produce a sensitive iodine distribution map in lung fields to quantify lung perfusion, which may indicate the existence of microvasculopathy according to poor subpleural perfusion.

This study aimed to examine the therapeutic efficacy of interventional treatment (pulmonary endarterectomy or/and balloon pulmonary angioplasty) in CTEPH with microvasculopathy.

Methods

We retrospectively reviewed poor subpleural perfusion (defined as subpleural spaces either not or minimally perfused in all segments) and hemodynamics of 70 consecutive CTEPH patients who underwent DECT before and after interventional therapy from January 2014 to January 2020.

Patients were divided according to poor subpleural perfusion in DECT images before treatment: a microvasculopathy group (MV group, n=37) or a non-microvasculopathy group (Non-MV group, n=33).

We evaluated clinical parameters as WHO functional class (WHO-Fc), 6-min walk distance, respiratory function test, cardiopulmonary exercise test, hemodynamic parameters, and DECT parameters at baseline and after the treatments. DECT parameters as quantitative evaluation of pulmonary blood volume (PBV) calculated as the average of entire lung iodine density.

Results

After interventional treatments, WHO-Fc improved in 33 patients in MV group, and 27 patients in Non-MV group (p=0.50).

In MV group, baseline mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR) and VE/VCO2 slope were higher (38.3±9.3 vs. 33.2±10.8 mmHg p=0.04, 818±394 vs. 539±289 dyne*sec/cm5 p&lt;0.01 and 43.7±11.3 vs. 35.2±6.9 p&lt;0.01, respectively) and PBV were lower (43.7±11.3 vs. 35.2±6.9 Hounsfield Unit p&lt;0.01) After the treatments, mPAP, PVR, VE/VCO2 slope and PBV showed almost equivalent between the groups (19.5±4.1 vs. 20.6±5.1 mmHg p=0.35, 272±111 vs 251±109 dyne*sec/cm5 p=0.42, 29.2±6.3 vs. 26.0±6.1 p=0.06 and 27.1±6.6 vs. 29.6±6.6 Hounsfield Unit p=0.13).

Diffusing capacity for carbon monoxide (%DLCO/VA) did not improve after treatment in both groups (MV group: 59.5±13.1 to 58.8±11.9% p=0.43. Non-MV group: 77.8±13.4% to 70.5±10.8% P&lt;0.01).

Conclusion

Hemodynamics, pulmonary perfusion, exercise capacities significantly improved after the treatments in spite of the existence or absence of microvasculopathy. However, DLCO which might indicate the existence of microvasculopathy did not improve. Interventional treatments could not improve microvasculopathy because of their limit of accessibilities.

Funding Acknowledgement

Type of funding source: None

Survival in patients with chronic thromboembolic pulmonary hypertension in the modern management era

Background

The management of non-operable chronic thromboembolic pulmonary hypertension (CTEPH) has recently evolved with the availability of balloon pulmonary angioplasty (BPA) and pulmonary vasodilators. We launched BPA program since 2011. The aim was to analyze survival and treatment efficacy in the modern management era.

Method and result

We retrospectively reviewed data from 143 consecutive CTEPH patients diagnosed in our university from January 2011 (i.e. after the availability of BPA) to December 2019. Forty-one patients underwent PEA, in these 25 patients underwent additional BPA (Hybrid group) and other patients were treated with only PEA (PEA group). Ninety patients underwent BPA (BPA group), remaining 12 patients had not undergone any interventional treatments. The 1- and 5-year survival rates of operated patients (n=41) were 97.4% and 90.0%, compared to96.9% and 86.9% in not-operated patients (n=102), respectively (p=0.579) (Figure). There was no death in Hybrid group. Percent decrease of pulmonary vascular resistance in PEA group, Hybrid group, BPA group were −75.4±9.9%, −74.3±11.8%, −56.3±22.2%, respectively (p&lt;0.01, one-way ANOVA). Absolute decrease of mean pulmonary artery pressure in each groups were −20.3±9.5mmHg, −24.5±8.8mmHg, −16.4±9.2mmHg, respectively (p&lt;0.01, one-way ANOVA).

Conclusion

There was no longer significant difference of long-term survival between operated and not-operated CTEPH. Moreover, Hybrid approach might have the potential to lead notable improvement in the prognosis of CTEPH. BPA and PEA would be mutually complementary therapies in the modern management era.

Figure 1

Funding Acknowledgement

Type of funding source: None

In-vitro fertilisation-embryo-transfer complicates the antenatal diagnosis of placenta accreta spectrum using MRI: a retrospective analysis

AIM

To evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) for the antenatal diagnosis of placenta accreta spectrum (PAS).

MATERIALS AND METHODS

Data from 95 patients with placenta previa or low-lying placenta who underwent MRI at Osaka University Hospital for the antenatal diagnosis of PAS between January 2013 and December 2018 were reviewed retrospectively. The antenatal MRI signs suggesting PAS were assessed. Patients were divided into two groups depending on whether they were diagnosed with PAS. Factors that affected PAS diagnosis were identified using multivariate analysis.

RESULTS

The diagnostic accuracy of MRI for detecting PAS was as follows: 71.4% sensitivity, 96.4% specificity, and area under the curve (AUC) of 0.839 (95% confidence interval [CI]: 0.73-0.91). The diagnostic accuracy was lower in patients with in-vitro fertilisation with embryo transfer (IVF-ET): 22.2% sensitivity, 93.3% specificity, and AUC=0.578 (95% CI: 0.417-0.724). On multivariate analysis, only IVF-ET showed a significant association with false-positive or -negative MRI diagnosis of PAS (adjusted odds ratio: 26.5; 95% CI: 2.42-289.4; p=0.007).

CONCLUSION

IVF-ET affects the antenatal diagnosis of PAS using MRI.

Ligation of MHC Class II Induces PKC-Dependent Clathrin-Mediated Endocytosis of MHC Class II

In addition to antigen presentation to CD4+ T cells, aggregation of cell surface major histocompatibility complex class II (MHC-II) molecules induces signal transduction in antigen presenting cells that regulate cellular functions. We previously reported that crosslinking of MHC-II induced the endocytosis of MHC-II, which was associated with decreased surface expression levels in murine dendritic cells (DCs) and resulted in impaired activation of CD4+ T cells. However, the downstream signal that induces MHC-II endocytosis remains to be elucidated. In this study, we found that the crosslinking of MHC-II induced intracellular Ca2+ mobilization, which was necessary for crosslinking-induced MHC-II endocytosis. We also found that these events were suppressed by inhibitors of Syk and phospholipase C (PLC). Treatments with a phorbol ester promoted MHC-II endocytosis, whereas inhibitors of protein kinase C (PKC) suppressed crosslinking-induced endocytosis of MHC-II. These results suggest that PKC could be involved in this process. Furthermore, crosslinking-induced MHC-II endocytosis was suppressed by inhibitors of clathrin-dependent endocytosis. Our results indicate that the crosslinking of MHC-II could stimulate Ca2+ mobilization and induce the clathrin-dependent endocytosis of MHC-II in murine DCs.

Reduction of respiratory motion artifacts in gadoxetate-enhanced MR with a deep learning-based filter using convolutional neural network

Objectives

To reveal the utility of motion artifact reduction with convolutional neural network (MARC) in gadoxetate disodium–enhanced multi-arterial phase MRI of the liver.

Methods

This retrospective study included 192 patients (131 men, 68.7 ± 10.3 years) receiving gadoxetate disodium–enhanced liver MRI in 2017. Datasets were submitted to a newly developed filter (MARC), consisting of 7 convolutional layers, and trained on 14,190 cropped images generated from abdominal MR images. Motion artifact for training was simulated by adding periodic k-space domain noise to the images. Original and filtered images of pre-contrast and 6 arterial phases (7 image sets per patient resulting in 1344 sets in total) were evaluated regarding motion artifacts on a 4-point scale. Lesion conspicuity in original and filtered images was ranked by side-by-side comparison.

Results

Of the 1344 original image sets, motion artifact score was 2 in 597, 3 in 165, and 4 in 54 sets. MARC significantly improved image quality over all phases showing an average motion artifact score of 1.97 ± 0.72 compared to 2.53 ± 0.71 in original MR images (p < 0.001). MARC improved motion scores from 2 to 1 in 177/596 (29.65%), from 3 to 2 in 119/165 (72.12%), and from 4 to 3 in 34/54 sets (62.96%). Lesion conspicuity was significantly improved (p < 0.001) without removing anatomical details.

Conclusions

Motion artifacts and lesion conspicuity of gadoxetate disodium–enhanced arterial phase liver MRI were significantly improved by the MARC filter, especially in cases with substantial artifacts. This method can be of high clinical value in subjects with failing breath-hold in the scan.

Key Points

• This study presents a newly developed deep learning–based filter for artifact reduction using convolutional neural network (motion artifact reduction with convolutional neural network, MARC).

• MARC significantly improved MR image quality after gadoxetate disodium administration by reducing motion artifacts, especially in cases with severely degraded images.

• Postprocessing with MARC led to better lesion conspicuity without removing anatomical details.

Preparation and evaluation of orally disintegrating tablets containing taste masked microparticles of acetaminophen

In the present work, taste masked particles of acetaminophen (AAP), a highly soluble bitter tasting drug, were developed and ODT containing the taste masked particles were prepared. Taste masked particles of AAP were prepared using different amounts of tetraglycerol polyricinoleate (TGPR) and Eudragit ®E100. Although the drug content ratio and drug recovery decreased with increasing TGPR, drug release from AAP-CR100 particles containing a large amount of TGPR was mostly suppressed for 2 min. Hence, AAP-CR100 was incorporated into ODT as taste masked particles for AAP. Three major disintegrants were used for ODT, and it was confirmed that the tensile strength of all formulations showed applicable hardness for handling. The AAP-CR100-CP(40) formulation containing crospovidone showed the shortest disintegration time and the drug release from AAP-CR100-CP(40) into pH 6.8 test solution was suppressed compared with commercial AAP tablets. Because the drug release from AAP-CR100-CP(40) into the pH 1.2 test solution was rapid, it was suggested that drug release from AAP-CR100-CP(40) is suppressed in the oral cavity, and the drug is released promptly in the stomach. Thus AAP-CR100-CP(40) may be useful as an ODT in which the dissolution of AAP in the oral cavity is suppressed.

P3644Plaque progression from normal vessel wall to fibroatheroma: lessons from over 5-year follow-up optical coherence tomography study

Background

Progression of atherosclerosis is a non-uniform process characterized by coexistence of normal vessel wall (NVW) and advanced fibroatheroma within the same cross-section (Figure). Plaque progression from NVW to fibroatheroma usually takes years, that has never been investigated in human.

Purpose

To investigate the incidence and related factors associated with atherosclerotic progression from NVW to fibroatheroma using long-term serial optical coherence tomography (OCT) follow-up data over 5 years.

Methods

We enrolled 47 vessels in 30 patients who had undergone serial OCT imaging over 5 years (average: 6.8 years). Baseline and follow-up OCT images were matched for longitudinal and circumferential location and OCT cross-sections that had NVW >30 degrees were enrolled. NVW was defined as vessel wall having OCT-detectable three-layer structure with intimal thickening ≤300μm. Cross-sections were diagnosed as +Progression when NVW in the cross-section reduced by >30 degrees during >5-year follow-up.

Results

In the present study, atherogenic progression from NVW to fibroatheroma was observed only in 37.2% of the enrolled cross-sections. On the other hand, despite an average long-term follow-up period of 6.8 years, the extent of NVW was maintained in 62.8% of cross-sections. The incidence of microchannel in adjacent fibroatheroma within the same cross-section (23.6% vs. 13.1%, p=0.023), eccentric plaque distribution (21.7% vs. 11.4%, p=0.019), and concave shape (6.6% vs. 0%, p=0.001) at baseline was significantly higher in cross-sections with +Progression than those without Progression. Average intimal thickness of NVW (187.2±64.9μm vs. 170.7±68.6μm; p=0.048) at baseline was significantly thicker in cross-sections with +Progression than those without. Multivariate analysis demonstrated that the presence of microchannel, eccentric plaque distribution and thicker average intimal thickness of NVW at baseline were independently associated with plaque progression during the follow-up.

Atheroma progression

Conclusion

The presence of microchannel in adjacent fibroatheroma, eccentric plaque distribution, and thicker intimal thickening of NVW were potentially associated with plaque progression from NVW to fibroatheroma.

P5022Dual-energy CT was effective to evaluate of microvasculopathy in chronic thromboembolic pulmonary hypertension

Background

The existence of microvasculopathy in patients with chronic thromboembolic pulmonary hypertension (CTEPH) had been suggested. However, the impact of microvasculopathy for pathophysiology had been unknown. Recently dual-energy CT (DECT) can produce a sensitive iodine distribution map as blood perfusion in lung fields to quantify lung perfusion, also can suggest the existence of microvasculopathy according to poor subpleural perfusion which was published previously.

Methods

We retrospectively reviewed poor subpleural perfusion (defined as subpleural spaces either not or minimally perfused in all segments) and hemodynamics of 83 treatment-naïve CTEPH patients who underwent DECT from February 2014 to Jan 2019. Patients were divided according to poor subpleural perfusion: a microvasculopathy group (n=44) or a non-microvasculopathy group (n=39).

We assessed cardiopulmonary exercise test, right heart catheterization and DECT parameters as quantitative evaluation of pulmonary blood volume (PBV). PBV was calculated as the average of entire lung iodine density.

Results

PBV value in non-microvasculopathy group showed significant inverse correlation with pulmonary vascular resistance (PVR) (y = 14236 x-1.028 r=−0.530, p<0.01).

PBV, SvO2, and %DLCO/VA were significantly lower (22.0 vs. 26.4, p<0.01, 61.3 vs. 66.0, p<0.01, and 59.2 vs 75.9 p<0.01), and systolic pulmonary arterial pressure, PVR, VE/VCO2 slope, BNP were higher (69.3 vs 60.6 p=0.04, 834 vs 586 p<0.01, 45.5 vs. 37.8, p=0.02, and 440 vs 122 p=0.04) in microvasculopathy group, while the other parameters were similar between the two groups.

Multivariate analysis revealed that %DLCO/VA was the only predictor of microvasculopathy (OR,0.895 [95% CI, 0.835 - 0.960]; P<0.01).

Conclusion

Pulmonary blood flow of patients in non-micorvasculopathy group showed inverse correlation with PVR. DECT was effective to assess the microvasculopathy in CTEPH. In our experience, less than 60% of non-operable CTEPH patients have microvasculopathy.

P6468Balloon pulmonary angioplasty for patients with symptomatic chronic thromboembolic disease without pulmonary hypertension

Background

Chronic thromboembolic disease (CTED) is characterised by thromboembolic stenosis and obstruction of pulmonary arteries without pulmonary hypertension. The treatment approach for symptomatic patients with CTED is still controversial. It has been reported the efficacy of surgical endarterectomy for patients with CTED, however that of balloon pulmonary angioplasty (BPA) for non-operable CTED has not been well established.

Method

We started aggressive BPA protocol for non-operable CTED patients who suffered from symptom with NYHA class II, III, and IV or limitation of exercise in spite of mean pulmonary artery pressure (mPAP) <25 mmHg since February 2014. We evaluated subjective symptoms, hemodynamic parameters by right heart catheter, and exercise capacity by cardiopulmonary exercise test at baseline and after the last BPA session.

Results

Twenty-three patients with CTED (68.7±10.5 years-old, 7 male) had undergone BPA. In these, 7 patients had received pulmonary vasodilators previously. After 2.9±1.3 sessions of BPA, Further improvement was observed in hemodynamics such as mPAP (21.6±2.3 to 17.1±2.6 mmHg, p<0.01), pulmonary vascular resistance (278±80 to 198±63 dyne/s/cm–5, p<0.01), which were accompanied with improved peak VO2 (14.6±4.4 to 17.4±4.2 ml/min/kg, p<0.01), VE/VCO2 slope (39.6±14.6 to 30.2±6.0, p=0.01), and functional class (I/II/III/IV; 0/10/12/1 to 9/12/2/0, p<0.01) (Table). All patients were tolerable, and no severe complication regarding to BPA.

Table 1 Variables Baseline After BPA (3 month) P value NYHA class (I / II / III / IV) 0 / 10 / 12 / 1 9 / 12 / 2 / 0 <0.01 Mean PAP (mmHg) 21.6±2.3 17.1±2.6 <0.01 PVR (dyne/sec/cm–5) 278±80 198±63 <0.01 6 MWD (m) 354±93 382±96 0.09 Peak VO2 (ml/min/kg) 14.6±4.4 17.4±4.2 <0.01

Conclusion

BPA may have the potential to achieve further improvement of exercise capacity and symptoms in CTED patients with acceptable risk, therefore BPA should be considered as a treatment option for symptomatic patients with non-operable CTED.

P5508Impact of CD14++CD16+ monocytes on coronary plaque vulnerability assessed by optical coherence tomography in coronary artery disease patients

Background

Diabetes mellitus has been known as an important factor of coronary artery disease (CAD) progression despite of widespread with lipid-lowering therapy. Although we have reported that large glucose fluctuation is associated with the development of cardiovascular disease in both diabetes mellitus (DM) and non-DM patients, the underlying mechanisms remain unclear.

Monocytes play a key role for atherosclerotic plaque formation. Monocytes in human peripheral blood are divided into three subsets: CD14++CD16− monocytes, CD14++CD16+ monocytes, and CD14+CD16++ monocytes. The CD14++CD16+ monocyte subset has recently received attention because it is reported to be associated with future cardiovascular events such as acute myocardial infarction. However, their impact on coronary plaque vulnerability in coronary artery disease (CAD) patients with or without DM remains unclear.

Purpose

The aim of this study was to investigate the impact of CD14++CD16+ monocyte levels on coronary plaque vulnerability and glucose fluctuation in stable CAD patients with well-regulated lipid levels.

Methods

This prospective observational study included 50 consecutive patients with CAD (DM [n=22], Non-DM [n=28]), receiving lipid-lowering therapy and undergoing coronary angiography and optical coherence tomography (OCT). Patients were divided into 3 tertiles according to the CD14++CD16+ monocyte percentages assessed by flow cytometry. Standard OCT parameters including lipid arc, lipid length, fibrous cap thickness (FCT) on lipid rich plaque, were assessed for 97 angiographically intermediate lesions (diameter stenosis: 30–70%). The presence of thin-cap fibroatheroma (TCFA), defined as a thin fibrous cap (<65μm) overlying a lipid-rich plaque (>90°), was also assessed. Daily glucose fluctuation assessed by using continuous glucose monitoring system was analyzed by measuring the mean amplitude of glycemic excursion (MAGE).

Results

CD14++CD16+ monocytes negatively correlated with FCT on lipid rich plaque (r=0.508, p<0.01) (Figure. 1). The presence of thin-cap fibroatheroma (TCFA) was increased stepwise according to the tertile of CD14++CD16+ monocytes (0 [tertile 1] vs. 5 [tertile 2] vs. 10 [tertile 3], p<0.01). CD14++CD16+ monocytes were a significant determinant of TCFA (OR 1.279, p=0.001). Although CD14++CD16+ monocytes were not significantly correlated with MAGE in DM patients (r=0.259, p=0.244), a significant relationship was found between CD14++CD16+ monocytes and MAGE in non-DM patients (r=0.477, p=0.018) (Figure 2).

Conclusions

CD14++CD16+ monocytes were associated with coronary plaque vulnerability in CAD patients with well-regulated lipid levels both in DM and non-DM patients. Cross-talk between glucose fluctuation and CD14++CD16+ monocytes may enhance plaque vulnerability, particularly in non-DM patients. CD14++CD16+ monocytes could be a possible therapeutic target for coronary plaque stabilization.

Hepatobiliary phase hypointense nodule without arterial phase hyperenhancement as a risk factor for late recurrence (>1 year) of hepatocellular carcinoma after surgery

AIM

To evaluate the value of magnetic resonance imaging (MRI) features, including liver stiffness measured by magnetic resonance elastography (MRE) and the presence of hepatobiliary phase (HBP) hypointense nodule without arterial phase hyperenhancement (APHE), for predicting late recurrence (>1 year) after surgery for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This retrospective study included 124 consecutive patients who had undergone surgery for HCC and preoperative MRI. After excluding patients with early recurrence within 1 year after surgery, 89 patients were analysed. Preoperative MRI images were reviewed by a radiologist to record imaging findings, including (1) liver stiffness by MRE, (2) size of the HCCs, (3) number of HCCs, and (4) presence of HBP hypointense nodule without APHE. Pathological findings included tumour grade, vascular/biliary/capsule invasion, and fibrosis stage of the liver. Considering imaging/pathological findings and patients' characteristics as dependent variables, Cox proportional hazards model analysis was performed to identify independent factors associated with late recurrence after surgery.

RESULTS

The median follow-up period was 37.3 months. During follow-up, 29 patients (32.5%) developed late recurrence after surgery. In multivariate analysis, underlying liver disease (viral hepatitis) and presence of HBP hypointense nodules without APHE (p=0.010 and 0.033, respectively) were independently associated with disease-free survival (DFS). Kaplan-Meier analysis revealed that patients with HBP hypointense nodules without APHE had a significantly lower DFS rate than those without the nodule (39.2% versus 74.1% at 3 years after surgery, p=0.008).

CONCLUSION

The presence of HBP hypointense nodules without APHE was an indicator of late recurrence after surgery for HCC.

Interlobular hyaline arteriopathy reflects severe arteriolopathy in renal allografts

AIM

The present study was performed to examine the clinicopathological significance of hyaline deposits in the smooth muscle of the interlobular artery (interlobular hyaline arteriopathy [IHA]) in renal allografts.

METHODS

Tissue specimens that included the interlobular artery from biopsies performed from January 2012 to December 2015, as well as specimens from biopsies performed ≥1 year after living kidney transplantation were analyzed. Biopsies of recipients with new-onset diabetes mellitus after transplantation were excluded, as well as those of recipients who had undergone transplantation because of diabetic nephropathy. Arteriolopathy was evaluated using the aah score determined by the Banff 2007 classification.

RESULTS

In total, 51 specimens with IHA lesions were identified among 381 biopsies obtained from 243 recipients performed ≥1 year after kidney transplantation. Among these 51 biopsies, 18 specimens had a score of aah3, 29 had a score of aah2, and four had a score of aah1. The incidence of IHA lesions was 3.6% at ≥1 to <4 years, 18.5% at ≥4 to <8 years, and 54.1% at ≥8 years. Older kidney grafts exhibited more IHA lesions. Among the biopsy specimens obtained ≥8 years after transplantation, no significant differences in the recipient or donor age, duration after transplantation, or prevalence of hypertension were observed between the IHA and non-IHA groups. The aah scores were significantly higher in the IHA group ≥8 years after transplantation as determined by the mean score test (P < 0.01).

CONCLUSION

IHA in renal allografts is associated with severe arteriolopathy.

Cancer survivors exhibit a different relationship between muscle strength and health-related quality of life/fatigue compared to healthy subjects

We investigated the difference in relationship between muscle strength and quality of life (QOL)/fatigue in long-term cancer survivors and healthy subjects. Thirty-six cancer survivors and 29 healthy subjects were assessed for body composition and bone status at the calcaneus using the Osteo Sono Assessment Index. Muscle strength was evaluated via handgrip and knee extensor strength. Health-related QOL was assessed using the Medical Outcome Study 36-item Short-Form Health Survey. Fatigue was measured using the brief fatigue inventory. Cancer survivors exhibited lower QOL scores in the physical functioning, physical role function, bodily pain and general health domains (p < .05). Grip and knee extension muscle strength in cancer survivors was positively correlated with the physical function and bodily pain of QOL (p < .05). The usual fatigue subscale score was only significantly higher in cancer survivors than in healthy subjects (p < .05). However, there were no correlations between muscle strength and fatigue in cancer survivors. Our results showed that muscle strength was an important factor for improving QOL in cancer survivors. We believe that the findings of this study will be relevant in the context of planning rehabilitation for cancer survivors.

Reduction effect of the quantity of radiation exposure and contrast media by image support system in transarterial chemoembolization for the treatment of hepatocellular carcinoma

BACKGROUND AND AIM

We confirmed the clinical utility of a three-dimensional navigation system during transarterial chemoembolization.

METHODS

We evaluated 128 tumors in 91 patients enrolled between May 2015 and August 2016. We evaluated the accuracy of the three-dimensional navigation imaging system for all tumors. We compared the patients who were able to undergo route detection using three-dimensional navigation with previously treated patients who underwent transarterial chemoembolization without using three-dimensional navigation (n = 21). For 38 patients who underwent super-selective microcatheter insertion after a feeding artery was identified by three-dimensional navigation, we confirmed the relationship between the tumors and contrasted liver parenchyma and divided the computed tomography hepatic arteriography findings into four grades. Grade 1: an overlap of > 5 mm, grade 2: an overlap between 0 and 5 mm, grade 3: the borders of the tumor within the liver parenchyma but in contact with the edges, and grade 4: a tumor outside the borders of the liver parenchyma.

RESULTS

Using the three-dimensional navigation system, we identified a tumor-feeding artery in 125/128 tumors (97.6%). Furthermore, this system allowed us to significantly reduce the volume of contrast media and the radiation exposure dose in patients undergoing an evaluation. We identified 15 grade 1 tumors (39.5%), 3 grade 2 tumors (7.9%), 11 grade 3 tumors (28.9%), and 9 grade 4 tumors (23.7%) according to our definitions.

CONCLUSION

The three-dimensional navigation is useful not only for patients but also for surgeons who have relatively little experience.

Early sorafenib induction after transarterial chemoembolization for unresectable hepatocellular carcinoma: Can sorafenib after TACE improve loco-regional control?

This prospective study aimed to estimate the efficacy of sorafenib therapy after transarterial chemoembolization (TACE) for unresectable hepatocellular carcinoma (HCC). Between July 2011 and March 2013, 17 patients were enrolled, 11 of whom received sorafenib therapy. Patients who previously received TACE for HCC and whose disease progressed within a six-month period were given 400-800 mg sorafenib orally, once or twice daily, within the 3 weeks after a second TACE (sorafenib after TACE group). The response to treatment, time to progression (TTP), overall survival (OS), and adverse events (AEs) were recorded. Of the 113 patients who underwent initial TACE for unresectable HCC between January 1995 and January 2013, 23 patients were selected who were treated with TACE alone, and for whom the interval between the second and third TACE treatments was <6 months (TACE alone group). The interval (TTP) was calculated between the third and fourth TACE treatments, then TTP was compared among the three groups: Sorafenib after TACE for > or <4 months; and TACE alone. During a median follow-up period of 34.4 months (range, 5.9-51.7 months) in both groups receiving sorafenib after TACE, sorafenib prolonged TTP (3.9 months) and OS (34.4 months). It was demonstrated that sorafenib use for >4 months prolonged TTP (5.7 months) significantly compared with use for <4 months (3.0 months) (P=0.002). The OS of patients given sorafenib for >4 months (35.9 months) was longer than that of patients who received the drug for <4 months (17.2 months), but this difference was not significant. In the TACE alone group, the median TTP between the third and fourth TACE treatments was 4.3 months. TTP decreased among the groups in the following order: Sorafenib for >4 months, TACE alone, and sorafenib for <4 months. There were three AEs of grade 3 in the present study. Two patients demonstrated a decrease in liver reserve function following sorafenib treatment, but improved immediately after sorafenib administration was stopped. Sorafenib induction early after TACE for unresectable HCC was generally well tolerated and significantly improved TTP. Further studies are required to confirm the safety and efficacy of this combination therapy.

Utility of percutaneous radiofrequency ablation alone or combined with transarterial chemoembolization for early hepatocellular carcinoma

Percutaneous radiofrequency ablation (RFA) combined with transarterial chemoembolization (TACE) is an effective, standard therapy against small hepatocellular carcinoma (HCC). However, there is debate regarding the effectiveness of RFA combined with TACE (RFA/TACE) compared with RFA alone. These two approaches were compared for the treatment of early HCC. The present study examined 83 HCC tumors in 83 patients treated with RFA between April 2007 and August 2014 at three medical institutions. All HCCs were single hypervascular tumors, with a median diameter of 16 mm (range, 6-30 mm). The overall survival (OS) rate of all patients (n=83) was 97.5% at 1 year, 82.8% at 3 years and 48.6% at 5 years, and the local recurrence rate of all patients was 14.3% at 1 year, 32.3% at 3 years and 36.5% at 5 years. The tumor-free survival (TFS) rate of all patients was 95.1% at 1 year, 56.3% at 3 years and 23.4% at 5 years. Compared with RFA alone, RFA/TACE significantly improved OS (P<0.001), intrahepatic distant recurrence (IDR; P=0.038) and TFS (P=0.010). A univariate analysis of prognostic indicators revealed that age <70 years (P=0.008), aspartate transaminase <40 IU/l (P=0.003), alanine aminotransferase <40 IU/l (P=0.006) and platelet count >10×10⁴/µl (P=0.05) were associated with a high survival rate. Multivariate analysis identified RFA/TACE [hazard ratio (HR), 0.108; P=0.001] as an independent prognostic indicator. RFA/TACE was identified as the only independent indicator of IDR (HR: 0.467; P=0.042) and TFS (HR: 0.452; P=0.012). RFA/TACE improved OS rate, IDR and TFS compared with RFA alone. The data suggested that RFA/TACE should be considered for the treatment of single hypervascular HCC.

Anatomical study of the inferior patellar pole and patellar tendon

In this study, detailed investigations into the shape of the inferior patellar pole, the site of the patellar tendon attachment, and the length and course of the patellar tendon were performed with the aim of examining the anatomical factors involved in the developmental mechanism of patellar tendinitis. The investigation examined 100 legs from 50 cadavers. The inferior patellar pole was classified into three types: pointed, intermediate, and blunt. The attachment of the patellar tendon to the inferior patellar pole was classified into two types: an anterior and a posterior. The length of the patellar tendon was measured from the tibial tuberosity to the inferior patellar pole. The pointed type was seen in 57% of legs, the intermediate type in 21%, and the blunt type in 22%. Twenty-one legs were the pointed type, as well as the anterior type. The patellar tendon was significantly shorter with the posterior type than with the anterior type. The blunt type also had a significantly shorter patellar tendon than the pointed type. In legs that were both the pointed type and the anterior type, the inferior patellar pole and the proximal posterior surface of the patellar tendon impinged during knee flexion due to the posterior tilt of the patella, suggesting the possibility that this may induce damage. With the posterior type and blunt type, on the other hand, the possibility of strong tensile stress on the tendon fibers of the posterior facet of the inferior patellar pole was suggested.