Novel treatment system using endoscopic ultrasound-guided high-intensity focused ultrasound: A proof-of-concept study.

AIM: High-intensity focused ultrasound (HIFU) is a novel minimally invasive local treatment of solid tumors. Endoscopic ultrasound-guided HIFU (EUS-HIFU) using mechanical effects would have potential benefits, including precise detection of target lesions and enhance drug delivery. The aim of this study is to develop EUS-HIFU device and to prove our concept in porcine model using a locally injected phase change nano droplet (PCND) as the sensitizer. METHOD: A phospholipid PCND contained volatile perfluoro-carbon liquids. The prototype HIFU apparatus comprised a small (20 × 20 mm) transducer with center frequency of 2.1 MHz, attachable to a linear EUS transducer. Under general anesthetic, a single porcine received EUS-guided injection of PCND. The HIFU transducer was placed laparotomically in the stomach, and the liver was ablated through the gastric wall. RESULTS: PCND was injected successfully and a distinct lesion was generated at the HIFU transducer focus only in injected areas that received HIFU exposure at 4.7 kW/cm2 at a duty cycle of 5 % (mean temporal intensity, 0.245 kW/cm2) for 30 s. The generated lesions were mechanically fractionated in macroscopic view. CONCLUSION: The concept of transluminal HIFU ablation using novel EUS-HIFU system was proved in a porcine animal model. This novel treatment system has great potential for future cancer treatment although further investigation in more animals and different organs are warranted.

Relationship of cerebral blood volume with arterial and venous flow velocities in extremely low-birth-weight infants.

Unstable cerebral blood flow is theorised to contribute to the occurrence of intraventricular haemorrhage (IVH) in extremely low-birth-weight infants (ELBWIs), which can be caused by increased arterial flow, increased venous pressure, and impaired autoregulation of brain vasculature. As a preliminary step to investigate such instability, we aimed to check for correlations of cerebral blood volume (CBV), as measured using near-infrared spectroscopy, with the flow velocities of the anterior cerebral artery (ACA) and internal cerebral vein (ICV), as measured using Doppler ultrasonography. Data were retrospectively analysed from 30 ELBWIs uncomplicated by symptomatic patent ductus arteriosus, which can influence ACA velocity, and severe IVH (grade ≥ 3), which can influence ICV velocity and CBV. The correlation between tissue oxygen saturation (StO2) and mean blood pressure was also analysed as an index of autoregulation. CBV was not associated with ACA velocity; however, it was significantly correlated with ICV velocity (Pearson R = 0.59 [95% confidence interval: 0.29-0.78], P = 0.00061). No correlation between StO2 and mean blood pressure was observed, implying that autoregulation was not impaired.    Conclusion: Although our findings are based on the premise that cerebral autoregulation was unimpaired in the ELBWIs without complications, the same result cannot be directly applied to severe IVH cases. However, our results may aid future research on IVH prediction by investigating the changes in CBV when severe IVH occurs during ICV velocity fluctuation. What is Known: • The pathogenesis of IVH includes unstable cerebral blood flow affected by increased arterial flow, increased venous pressure, and impaired cerebral autoregulation. • The approaches that can predict IVH are under discussion. What is New: • ACA velocity is not associated with CBV, but ICV velocity is significantly correlated with CBV. • CBV measured using NIRS may be useful in future research on IVH prediction.

Brain injury following mild hypoxic-ischemic encephalopathy in neonates-Ten-year experience in a tertiary perinatal center.

OBJECTIVE: We aimed to evaluate abnormal magnetic resonance imaging (MRI) findings in neonates with mild hypoxic-ischemic encephalopathy (HIE). STUDY DESIGN: This was a single-center, retrospective study of mild HIE conducted from 2011 to 2020. Almost all neonates with mild HIE received management targeted to a temperature of 36 ± 0.5°C for 72 h and underwent MRI (135 of 145). We evaluated medical records and assessed amplitude-integrated electroencephalography (aEEG). RESULT: All participants survived until discharge. Abnormal MRI findings were present in 23/135 (17%) neonates. The normal versus abnormal MRI-finding groups had similar characteristics, except discontinuous aEEG patterns (p = 0.002) and inotropic drugs (p = 0.035). Regression analyses showed discontinuous aEEG patterns (odds ratio = 19.3, 95% confidence interval=1.88-197, p = 0.013) being associated with higher odds of abnormal MRI findings. CONCLUSION: Our study suggests that a discontinuous aEEG pattern is associated with abnormal MRI findings and can be used to discuss the definition of mild HIE.

Fetal-onset malignant rhabdoid tumor: a case report.

BACKGROUND: A fetal-onset cervical mass may cause postnatal airway obstruction, and ex utero intrapartum treatment (EXIT) to secure the airway while maintaining fetal-placental circulation may be life-saving. Malignant rhabdoid tumors (MRT) are highly aggressive tumors, and when they develop in utero, the prognosis is even worse, with almost no reports of survival beyond the neonatal period. Herein, we report a case of a primary cervical MRT and describe our treatment using EXIT for securing the airway, wherein the infant's life was saved. CASE PRESENTATION: A 40-year-old Japanese woman with no relevant medical or surgical history was diagnosed with a fetal left cervical mass and polyhydramnios during the third trimester. Fetal magnetic resonance imaging indicated the possibility of postnatal airway obstruction, and delivery using EXIT was planned. The infant was delivered by a planned cesarean section at 39 weeks and 5 days gestation, and tracheostomy was performed using EXIT. Postnatal contrast-enhanced computed tomography revealed suspected metastatic lesions in the subcutaneous tissue, lungs, and thymus, in addition to the mass in the left cervical region. MRT was diagnosed by biopsy of a subcutaneous mass in the left thigh, and chemotherapy with vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide was initiated. The tumors regressed, and the infant was successfully weaned from artificial ventilation. After discharge from the hospital, she had a recurrent cervical mass and intracranial metastasis, and radiotherapy was initiated. CONCLUSIONS: In our case, fetal diagnosis enabled advance planning of delivery using EXIT, thus saving the infant's life. The use of chemotherapy for MRT, which has a poor prognosis, allowed tumor regression and enabled the infant to survive beyond the neonatal period.

The Relationship between Serum Total Bilirubin and Severity of Hypoxic Injury in Neonatal Hypoxic-Ischemic Encephalopathy.

INTRODUCTION: Bilirubin has been found to be a natural antioxidant protecting the body from oxidative stress. This study aims to investigate the severity of neonatal hypoxic injury on bilirubin levels to clarify the physiological role of bilirubin. STUDY DESIGN: Using lactate as a biomarker for the severity of hypoxic injury, we retrospectively analyzed the association of admission lactate levels on serum total bilirubin (TB) levels following birth in neonates with hypoxic-ischemic encephalopathy (HIE). We created a univariate linear regression model to predict TB using the admission lactate level as a predictor. We also performed a multivariate linear regression analysis to predict TB with admission lactate levels that included phenobarbital cumulative dosage, admission hematocrit, and subgaleal hemorrhage as predictor variables. RESULTS: A total of 86 patients were studied. Admission lactate levels had a significant negative effect on TB from admission to 3 days of life. The standardized regression coefficient for admission lactate on TB was -0.37 (admission), -0.42 (day 1), -0.32 (day 2), and -0.28 (day 3). A similar negative effect of admission lactate on TB levels was also observed in the multivariate linear regression model even after controlling for the other variables. CONCLUSION: These results are consistent with the hypothesis that bilirubin functions as an antioxidant in vivo, and is consumed by scavenging free radicals in proportion to the severity of hypoxic injury. KEY POINTS: · Lactate levels have a negative effect on serum TB levels in patients with neonatal HIE.. · Bilirubin might work as a natural antioxidant to protect the body from oxidative stress.. · Serum TB might be a marker for the severity of hypoxic injury..

The Acylcarnitine Profile in Dried Blood Spots is Affected by Hematocrit: A Study of Newborn Screening Samples in Very-Low-Birth-Weight Infants.

OBJECTIVE: The acylcarnitine profile is analyzed in dried blood spots (DBS) to screen for inborn errors of metabolism. Hematocrit (Ht) is known to affect the result of quantitative analyses of DBS samples; however, the effects of Ht on the acylcarnitine profiles in DBS have not been studied in actual samples from newborns. STUDY DESIGN: The acylcarnitine profiles in DBS for newborn screening tests and Ht levels of very-low-birth-weight infants were obtained from medical records. We investigated the relationship between Ht and each acylcarnitine using Pearson's correlation coefficient (r). RESULTS: We examined 77 newborns in this study. There was a significantly positive correlation between Ht and C0, C2, C12, C16, C18, C18:1, and C18:1-OH, respectively (p < 0.0025). The correlation was the greatest on C2 (r = 0.59). CONCLUSION: This study clarifies that Ht and C0, C2, C12, C16, C18, C18:1, and C18:1-OH are significantly correlated in DBS, which is consistent with previous studies. Hence, the effect of Ht should be considered when interpreting the results of acylcarnitine profiles in DBS. KEY POINTS: · Acylcarnitine profile in dried blood spots (DBS) is affected by the hematocrit (Ht) of the sample.. · There are positive correlations between Ht and C0, C2, C12, C16, C18, and C18:1-OH in DBS.. · We should be aware of the effects of Ht on acylcarnitine profiles in DBS..

Extreme Prematurity and Pulmonary Outcomes Program in Saitama: Protocol for a Prospective Multicenter Cohort Study in Japan.

BACKGROUND: Because of the improvements in survival rates for preterm infants, not only the rates of bronchopulmonary dysplasia (BPD) but also those of long-term respiratory complications of premature birth are increasing, resulting in financial and health burdens in developed countries. Thus far, the risk factors of respiratory morbidities in extremely preterm infants remain unknown. Furthermore, the definition and the predictive ability of BPD for long-term respiratory outcomes are yet to be determined. OBJECTIVE: The objective of our study, Extreme Prematurity and Pulmonary Outcomes Program in Saitama, is to develop the diagnostic criteria for BPD and to determine the prognostic factors contributing to the long-term pulmonary outcomes manifesting in extremely preterm infants. METHODS: The Extreme Prematurity and Pulmonary Outcomes Program in Saitama is an observational prospective cohort study performed by a consortium of six neonatal intensive care units (NICUs) in Saitama, Japan. The subjects included in this study are infants (from each clinical center) with gestational ages 22 to 27 weeks. The target is 400 subjects. This study aims to determine the definition of BPD and other perinatal factors that accurately predict the long-term pulmonary outcomes in survivors of extreme prematurity. Moreover, the association between BPD and postprematurity respiratory disease will be investigated using generalized linear models. RESULTS: The protocol and consent forms were evaluated and approved on September 5, 2019, by the Ethics Committee of Saitama Medical Center, Saitama Medical University. Enrollment began on April 1, 2020. It is expected to end on March 31, 2023. The follow-up for 1 year corrected age is expected to continue through the middle of 2024. CONCLUSIONS: The Extreme Prematurity and Pulmonary Outcomes Program in Saitama incorporates aspects of neonatal care in secondary- and tertiary-level NICUs to develop existing research studies on the definition of BPD, objective biomarkers, and outcome measures of respiratory morbidity in extremely preterm infants beyond NICU hospitalization, thereby leading to a novel understanding of the nature and natural history of BPD and potential mechanistic and therapeutic targets in at-risk subjects. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/22948.

Ultrasound Sub-pixel Motion-tracking Method with Out-of-plane Motion Detection for Precise Vascular Imaging.

Ultrasound vascularity imaging provides important information for differential diagnosis of tumors. Peak-hold (PH) is a useful technique for precisely imaging small vessels by selecting a maximum brightness in each pixel through the frames obtained sequentially. To use PH successfully one needs motion compensation to reduce image blur, but out-of-plane motion cannot be avoided. To address this problem, we developed a sub-pixel motion-tracking method with out-of-plane motion detection (OPMD). It is a combination of the sum of the absolute differences (SAD) method and the Kanade-Lucas-Tomasi method and can be accurately applied to various motions. The value from OPMD (γ) is defined as a statistical value obtained from the distribution of residual values in the SAD procedure with the obtained frames. The value is ideally 0, and the frames having large γ are removed from the PH procedure. The accuracy of the proposed tracking method was found by a simulation study to be approximately 20 µm. We also found, through a phantom experiment, that the value of γ sensitively increased enough to detect out-of-plane motion. Most important, γ begins to increase before tracking errors occur. This suggests that OPMD can be used to predict tracking errors and effectively remove frames from the PH procedure. An in vivo experiment with a rabbit showed that the PH image obtained with motion tracking clearly revealed peripheral vessels that were blurred in the PH image obtained without motion tracking. We also found that the image quality becomes better when OPMD was used to remove frames including out-of-plane motion.

Pulmonary Vascular Resistance Is Associated With Brachial-Ankle Pulse-Wave Velocity and Adverse Clinical Outcomes in Patients With Heart Failure With Preserved Ejection Fraction.

BACKGROUND: The precise mechanisms underlying the high prevalence of pulmonary hypertension (PH) with increased pulmonary vascular resistance (PVR) in heart failure with preserved ejection fraction (HFpEF) remain largely unknown. Measurements of brachial-ankle pulse wave velocity (baPWV) have been shown to be useful for risk assessment in HF patients. Thus, this study sought to define the association of PVR with baPWV and clinical outcomes in HFpEF. METHODS AND RESULTS: Patients with HFpEF (n = 198) had measurements of baPWV and PVR by right heart catheterization, and were prospectively followed-up for <96 months or until the occurrence of a composite of all-cause death, hospitalization with worsening HF, and nonfatal acute coronary syndrome. RESULTS: Multivariate logistic analysis showed that baPWV was independently associated with PH with increased PVR (P < .001). During the follow-up period, 46 clinical events occurred. Multivariate Cox proportional hazards analysis showed that PH with increased PVR was a significant predictor of adverse outcomes after adjustment for conventional risk factors (HR 1.96, 95% CI 1.03-3.76, P = .04). CONCLUSIONS: PH with increased PVR was associated with increased baPWV and adverse clinical outcomes in HFpEF. Thus, increased arterial stiffness may contribute to increased risk predictability of PVR for patients with HFpEF.

A Pilot Study of Soluble Form of LOX-1 as a Novel Biomarker for Neonatal Hypoxic-Ischemic Encephalopathy.

OBJECTIVE: To evaluate the soluble form of lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) as a biomarker of severity staging and prognosis in neonatal hypoxic-ischemic encephalopathy (HIE). STUDY DESIGN: We performed an observational study enrolling 27 infants with HIE and 45 control infants of gestational age ≥36 weeks and birth weight ≥1800 g. The HIE criteria were pH ≤7.0 or a base deficit ≥16 mmol/L within 60 minutes after birth, and a 10-minute Apgar score ≤5 or resuscitation time ≥10 minutes. HIE severity was evaluated using modified Sarnat staging. We measured plasma sLOX-1 level and assessed general and neurologic signs at discharge, and classified infants with no neurosensory impairments as intact survival. RESULTS: sLOX-1 level within 6 hours after birth was correlated with the severity of HIE. sLOX-1 differentiated moderate-severe HIE (median, 1017 pg/mL; IQR, 553-1890 pg/mL) from mild HIE (median, 339 pg/mL; IQR, 288-595 pg/mL; P = .007). The sensitivity and specificity of the differentiation with a cutoff value of ≥550 pg/mL were 80.0% and 83.3%, respectively. In 19 infants with therapeutic hypothermia, a sLOX-1 cutoff value of <1000 pg/mL differentiated intact survival (median, 761 pg/mL; IQR, 533-1610 pg/mL) from death or neurosensory impairment (median, 1947 pg/mL; IQR, 1325-2506 pg/mL; P = .019) with 100% specificity and a positive predictive value. CONCLUSION: sLOX-1 may be a useful biomarker of neonatal HIE for severity staging and outcome prediction. Further investigations will facilitate its clinical use.

Correction to: Accuracy and limitations of vector flow mapping: left ventricular phantom validation using stereo particle image velocimetory.

The original version of this article unfortunately contained a mistake. The conflict of interest statement was missing in the article. The CoI statement is given below.

Transluminal Approach with Bubble-Seeded Histotripsy for Cancer Treatment with Ultrasonic Mechanical Effects.

Bubble-seeded histotripsy (BSH) is a newly developed ultrasound-based mechanical fractionation technique using locally injected phase change nanodroplets (PCNDs) as sensitizers. The PCNDs are a kind of microbubble precursor compressed into submicron-size in droplets form, which were designed for local administration and will expand into microbubbles under ultrasound exposure. Previously, we reported that a combination of PCNDs injection and pulsed high-intensity focused ultrasound (pHIFU) with an acoustic intensity as low as about 3 kW/cm2 at 1.1 MHz, which is similar to the acoustic intensity of currently available HIFU coagulation therapy, was enough to induce tissue fractionation after significant antitumor effects in an in vivo study. Toward therapeutic application of BSH to deep-seated tissues such as the pancreas, the transluminal approach, using endoscopic ultrasound was thought to be ideal. Therefore, for a preliminary examination, we developed a new transducer with a small aperture (20- × 20-mm square) and long focal length (35 mm), operating at 2.1 MHz that could be attached to an EUS-mimicking probe. With the newly developed transducer and locally injected PCNDs, predictable tissue mechanical fractionation was observed in both ex vivo and in vivo studies at acoustic intensities that were too low to induce any significant bioeffects (around 4 kW/cm2) without using PCNDs. For in situ monitoring of the treatment site during a procedure, the degree of attenuation of microbubble motions after exposing the microbubbles to pHIFU was monitored, using ultrafast echographic imaging. Microbubble movements were observed to be largest at 25-30 s after pHIFU exposure. On the contrary, after 40 s, the movement of microbubbles decreased to the same level as at the start of the procedure, suggesting that an overdose of pHIFU exposure causes coagulation attributable to the thermal effect caused by absorption of the energy. Those results were promising for expanding the application of BSH for a transluminal approach, using a small transducer under real-time monitoring.

A posteriori accuracy estimation of ultrasonic vector-flow mapping (VFM).

ABSTRACT: A novel method, called a posteriori "VFM accuracy estimation" (VAE), for resolving an intrinsic VFM problem is proposed. The problem is that VFM uncertainty can easily vary according to blood flows through an echocardiographic imaged plane (i.e., "through-plane" flows), and it is unknown. Knowing the VFM uncertainty for each patient will make it possible to refine the quality of VFM-based diagnosis. In the present study, VAE was derived on the basis of an error-propagation analysis and a statistical analysis. The accuracy of VAE with a pulsatile left-ventricle phantom was experimentally investigated for realistic cases with through-plane flows. VAE was validated by comparing VFM uncertainty (S.D.) estimated by VAE with VFM uncertainty measured by particle-image velocimetry (PIV) for different imaged planes. VAE accurately estimated the S.D. of VFM uncertainty measured by PIV for all cases with different image planes (R > 0.6 and p < 0.001). These findings on VFM accuracy will provide the basis for widespread clinical application of VFM-based diagnosis.

Nasopharynx is well-suited for core temperature measurement during hypothermia therapy.

BACKGROUND: Rectal temperature is commonly used as the core temperature during therapeutic hypothermia therapy in neonates with hypoxic-ischemic encephalopathy (HIE). The purpose of this study was to examine whether nasopharyngeal temperature could serve as a substitute for rectal temperature. METHODS: We prospectively investigated 40 neonates with HIE who underwent therapeutic hypothermia by selective head cooling, which involved cooling the body to 34°C for 72 h. During this period, nasopharyngeal temperature was measured and compared with rectal temperature every hour. RESULTS: For 40 neonates included in this study, the mean rectal and nasopharyngeal temperatures were 34.3 ± 0.4°C (n = 2920) and 34.3 ± 0.4°C (n = 2920), respectively. Nasopharyngeal temperature strongly correlated with rectal temperature (R2 = 0.623, P < 0.0001) and magnitude of the mean difference between nasopharyngeal and rectal temperature varied little during the 72 h of therapeutic hypothermia. CONCLUSIONS: Nasopharyngeal temperature in neonates with perinatal HIE undergoing therapeutic hypothermia may be a suitable substitute for rectal temperature.

Accuracy and limitations of vector flow mapping: left ventricular phantom validation using stereo particle image velocimetory.

BACKGROUND: The accuracy of vector flow mapping (VFM) was investigated in comparison to stereo particle image velocimetry (stereo-PIV) measurements using a left ventricular phantom. VFM is an echocardiographic approach to visualizing two-dimensional flow dynamics by estimating the azimuthal component of flow from the mass-conservation equation. VFM provides means of visualizing cardiac flow, but there has not been a study that compared the flow estimated by VFM to the flow data acquired by other methods. METHODS: A reproducible three-dimensional cardiac blood flow was created in an optically and acoustically transparent left-ventricle phantom, that allowed color-flow mapping (CFM) data and stereo-PIV to be simultaneously acquired on the same plane. A VFM algorithm was applied to the CFM data, and the resulting VFM estimation and stereo-PIV data were compared to evaluate the accuracy of VFM. RESULTS: The velocity fields acquired by VFM and stereo-PIV were in excellent agreement in terms of the principle flow features and time-course transitions of the main vortex characteristics, i.e., the overall correlation of VFM and PIV vectors was R = 0.87 (p < 0.0001). The accuracy of VFM was suggested to be influenced by both CFM signal resolution and the three-dimensional flow, which violated the algorithm's assumption of planar flow. Statistical analysis of the vectors revealed a standard deviation of discrepancy averaging at 4.5% over the CFM velocity range for one cardiac cycle, and that value fluctuated up to 10% depending on the phase of the cardiac cycle. CONCLUSIONS: VFM provided fairly accurate two-dimensional-flow information on cardio-hemodynamics. These findings on VFM accuracy provide the basis for VFM-based diagnosis.

Mitochondrial Disease as a Cause of Neonatal Hemophagocytic Lymphohistiocytosis.

Diagnosis of mitochondrial respiratory chain disorder (MRCD) is often difficult. Its pathogenesis is still unclear. We diagnosed MRCD by measuring the activity of the mitochondrial respiratory chain enzyme, and the patient also had hemophagocytic lymphohistiocytosis (HLH). A preterm female infant was born at 34 weeks of gestation. On day 6, HLH was revealed by bone marrow aspiration. She died on day 10 due to uncontrollable HLH. An autopsy was performed, and we measured the activity of the mitochondrial respiratory chain enzyme in the liver, muscle, and heart. The activity of complex I was decreased in all tissues. As we could not prove another origin of the HLH, she was diagnosed as having HLH caused by MRCD. It is useful to measure the activity of the mitochondrial respiratory chain enzyme for diagnosing MRCD. MRCD, which has a severe clinical course, may be related to HLH.

New approach for local cancer treatment using pulsed high-intensity focused ultrasound and phase-change nanodroplets.

PURPOSE: The aim of this study was to investigate the combination effects of pulsed HIFU (pHIFU) and phase-change nanodroplets (PCND) as a sensitizer on efficient induction of mechanical effects of pHIFU and chemically enhanced tumor growth inhibition for local anti-tumor therapy. METHOD: Changes in growth of colon 26 tumor tissue inoculated onto CDF1 mice were evaluated by the following treatments. (1) pHIFU exposure (1.1 MHz, 3.2 kW/cm(2), 300 cycles, and 50 ms interval) for 60 s, (2) PCND (1 %) injection, (3) adriamycin (4 mg/kg) injection, (4) pHIFU exposure after PCND injection, and (5) pHIFU exposure after PCND + adriamycin injection simultaneously. RESULTS: Significant changes in tumor growth were observed in the group with combination of pHIFU and PCND, although single therapy did not show any significant difference. PCND enhanced mechanical tissue fractionation by pHIFU, which was detectable by Real-time tissue elastography. Moreover, the combination of pHIFU and PCND + Adriamycin suppressed the tumor growth for 2 weeks, and 3 of 4 mice did not show any sign of regrowth during the 30-day observation. CONCLUSION: The combination of pHIFU and PCND exerted a significant anti-tumor effect and may be a new candidate for treatment of locally advanced cancer.

Assessment of carotid plaque neovascularization using quantitative analysis of contrast-enhanced ultrasound imaging is useful for risk stratification in patients with coronary artery disease.

BACKGROUND: Contrast-enhanced ultrasound (CEUS) of the carotid artery is a potential technique for imaging plaque neovascularization, a feature of unstable atherosclerotic plaques. This study examined whether assessment of intra-plaque neovascularization of the carotid artery using CEUS provides prognostic information in patients with coronary artery disease (CAD). METHODS: A total of 206 patients with stable CAD underwent a CEUS examination of the carotid artery and were followed up prospectively for <38 months or until a cardiac event (cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris (uAP) requiring unplanned coronary revascularization, or heart failure requiring hospitalization). The degree of contrast signals measured within the carotid plaque was quantified by calculating the mean gray scale level within the region of interest of the carotid plaque, expressed as plaque enhanced intensity. RESULTS: During the follow-up period, 31 events occurred (2 cardiac deaths, 7 non-fatal MIs, 16 uAP, and 6 heart failure). Multivariate Cox proportional hazard analysis showed that plaque enhanced intensity was a significant predictor of cardiac events independent of traditional risk factors (HR, 1.13; 95% CI, 1.05-1.21; p<0.001). The addition of the plaque enhanced intensity to traditional risk factors resulted in net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.62, p=0.001; and IDI 0.106, p=0.002). CONCLUSIONS: The assessment of carotid plaque neovascularization using quantitative analysis of CEUS may be useful for risk stratification in patients with CAD.