Intraoperative short-term blood pressure variability and postoperative acute kidney injury: a single-center retrospective cohort study using sample entropy analysis.

Background: To investigate if intraoperative very short-term variability in blood pressure measured by sample entropy improves discrimination of postoperative acute kidney injury after noncardiac surgery.

Methods: Adult surgical patients undergoing general, thoracic, urological, or gynecological surgery between August 2016 to June 2017 at Seoul National University Hospital were included. The primary outcome was acute kidney injury stage 1, defined by the Kidney Disease: Improving Global Outcomes guidelines.

Computer vision digitization of smartphone images of anesthesia paper health records from low-middle income countries.

Background: In low-middle income countries, healthcare providers primarily use paper health records for capturing data. Paper health records are utilized predominately due to the prohibitive cost of acquisition and maintenance of automated data capture devices and electronic medical records. Data recorded on paper health records is not easily accessible in a digital format to healthcare providers.

Myocardial perfusion imaging-derived left ventricular strain: Regional abnormalities associated with transthyretin cardiac amyloidosis.

Background: Transthyretin (ATTR) cardiac amyloidosis is associated with an apical-sparing strain pattern on TTE. We hypothesize that strain indices derived from myocardial perfusion imaging (MPI) can identify this abnormality.

Methods: A group with ATTR amyloidosis was compared to age-matched controls with LVH but without amyloidosis who underwent PET or SPECT MPI.

4D display of CT LV endocardial and epicardial models morphed from PET Rb-82 perfusion studies accurately quantifies segmental myocardial thickening.

Background: MPI-derived LV wall thickening assessments for diagnostic purposes has been part of clinical guidelines for two decades. It relies on visual evaluation of tomographic slices or regional quantification displayed in 2D polar maps. 4D displays have not entered clinical usage nor have they been validated on their potential to provide equivalent information.

Computer assisted interpretation of Tc-99m mercaptoacetyltriglycine diuretic scintigraphy enhances resident performance.

Objective: iRENEX is a software module that incorporates scintigraphic and clinical data to interpret 99m Tc- mercaptoacetyltriglycine (MAG3) diuretic studies and provide reasons for their conclusions. Our objectives were to compare iRENEX interpretations with those of expert physicians, use iRENEX to evaluate resident performance and determine if iRENEX could improve the diagnostic accuracy of experienced residents.

Methods: Baseline and furosemide 99m Tc-MAG3 acquisitions of 50 patients with suspected obstruction (mean age ± SD, 58.

Left Ventricular Strain from Myocardial Perfusion PET Imaging: Method Development and Comparison to 2-Dimensional Echocardiography.

This study aimed to develop a measure of longitudinal, radial, and circumferential myocardial strain at rest and regadenoson during pharmacologic stress using Rb PET electrocardiography-gated myocardial perfusion imaging (MPI). We retrospectively identified 80 patients who underwent rest and regadenoson-stress CT attenuation-corrected Rb PET and had a standard resting transthoracic echocardiogram (TTE) with global longitudinal strain (GLS) analysis within 3 mo. A method was developed to compute longitudinal, radial, and circumferential strain from PET MPI at stress and rest.

Clinically viable myocardial CCTA segmentation for measuring vessel-specific myocardial blood flow from dynamic PET/CCTA hybrid fusion.

Background: Positron emission tomography (PET)-derived LV MBF quantification is usually measured in standard anatomical vascular territories potentially averaging flow from normally perfused tissue with those from areas with abnormal flow supply. Previously we reported on an image-based tool to noninvasively measure absolute myocardial blood flow at locations just below individual epicardial vessel to help guide revascularization. The aim of this work is to determine the robustness of vessel-specific flow measurements (MBF) extracted from the fusion of dynamic PET (dPET) with coronary computed tomography angiography (CCTA) myocardial segmentations, using flow measured from the fusion with CCTA manual segmentation as the reference standard.

Dynamic cardiac PET motion correction using 3D normalized gradient fields in patients and phantom simulations.

Unlabelled: This work expands on the implementation of three-dimensional (3D) normalized gradient fields to correct for whole-body motion and cardiac creep in [N-13]-ammonia patient studies and evaluates its accuracy using a dynamic phantom simulation model.

Methods: A full rigid-body algorithm was developed using 3D normalized gradient fields including a multi-resolution step and sampling off the voxel grid to reduce interpolation artifacts. Optimization was performed using a weighted similarity metric that accounts for opposing gradients between images of blood pool and perfused tissue without the need for segmentation.

Determination of [N-13]-ammonia extraction fraction in patients with coronary artery disease by calibration to invasive coronary and fractional flow reserve.

Background: This study presents a new extraction fraction (EF) model based on physiological measures of invasive coronary flow reserve (CFR) and fractional flow reserve (FFR) in patients with suspected coronary artery disease (CAD) and normal index microcirculatory resistance (IMR). To ascertain the clinical relevance of the new EFs, flow measurements using the newly patient-determined EFs were compared to flow measurements using traditional animal-determined EFs.

Methods: 39 patients were retrospectively selected that included a total of 91 vascular territories with invasive coronary angiography physiological measures.

Vessel-specific quantification of absolute myocardial blood flow, myocardial flow reserve and relative flow reserve by means of fused dynamic NH PET and CCTA: Ranges in a low-risk population and abnormality criteria.

Objectives: The goal of the present work is to present a novel methodology for the extraction of MBF, MFR and RFR along coronary arteries by means of multimodality image fusion of dynamic PET and CCTA images.

Background: FFR is the reference standard to identify flow-limiting lesions, but its invasiveness limits broad application. New noninvasive methodologies are warranted to stratify patients and guide treatment.

Diagnostic performance of an artificial intelligence-driven cardiac-structured reporting system for myocardial perfusion SPECT imaging.

Objectives: To describe and validate an artificial intelligence (AI)-driven structured reporting system by direct comparison of automatically generated reports to results from actual clinical reports generated by nuclear cardiology experts.

Background: Quantitative parameters extracted from myocardial perfusion imaging (MPI) studies are used by our AI reporting system to generate automatically a guideline-compliant structured report (sR).

Method: A new nonparametric approach generates distribution functions of rest and stress, perfusion, and thickening, for each of 17 left ventricle segments that are then transformed to certainty factors (CFs) that a segment is hypoperfused, ischemic.

Development and validation of an automatic method to detect the latest contracting viable left ventricular segments to assist guide CRT therapy from gated SPECT myocardial perfusion imaging.

Objectives: The purpose of this study is to use ECG-gated SPECT MPI to detect the latest contracting viable left ventricular (LV) segments to help guide the LV probe placement used in CRT therapy and to validate segment selection against the visual integration method by experts.

Methods: For each patient, the resting ECG-gated SPECT MPI short-axis images were sampled in 3D to generate a polar map of the perfusion distribution used to determine LV myocardial viability, and to measure LV synchronicity using our phase analysis tool. In the visual integration method, two experts visually interpreted the LV viability and mechanical dyssynchrony from the short-axis images and polar maps of viability and phase, to determine the latest contracting viable segments using the 17-segment model.

Tc-MAG: Image Wisely.

Purpose To determine if commonly administered doses of technetium 99m (Tc) mertiatide (MAG) in the range of 300-370 MBq (approximately 8-10 mCi) contribute to image interpretation and justify the resulting radiation exposure. Materials and Methods The respective institutional review boards approved this HIPAA-compliant study and waived informed consent. Baseline and furosemide Tc-MAG imaging examinations in 50 patients suspected of having renal obstruction and 48 patients suspected of having renovascular hypertension (RVH) were randomly selected from archived databases and were independently scored by three experienced readers without access to 2-second flow images.

Diagnostic performance of the quantification of myocardium at risk from MPI SPECT/CTA 2G fusion for detecting obstructive coronary disease: A multicenter trial.

Background: The effective non-invasive identification of coronary artery disease (CAD) and its proper referral for invasive treatment are still unresolved issues. We evaluated our quantification of myocardium at risk (MAR) from our second generation 3D MPI/CTA fusion framework for the detection and localization of obstructive coronary disease.

Methods: Studies from 48 patients who had rest/stress MPI, CTA, and ICA were analyzed from 3 different institutions.

Assessment of I-mIBG and Tc-tetrofosmin single-photon emission computed tomographic images for the prediction of arrhythmic events in patients with ischemic heart failure: Intermediate severity innervation defects are associated with higher arrhythmic risk.

Rationale: I-mIBG planar image heart-to-mediastinum ratios effectively risk-stratify heart failure (HF) patients. The value of single-photon emission computed tomographic (SPECT) imaging for identifying increased risk of ventricular arrhythmias is less clear. This study sought to determine if findings from simultaneous interpretation of I-mIBG and Tc-tetrofosmin SPECT are predictive of arrhythmic events (ArEs).

Prognostic significance of (123)I-mIBG SPECT myocardial imaging in heart failure: differences between patients with ischaemic and non-ischaemic heart failure.

Aims: The purpose of this study was to examine the prognostic significance of uptake patterns on quantitative myocardial (123)I-mIBG and (99m)Tc-tetrofosmin SPECT imaging in heart failure (HF) subjects and to assess the differences between patients with ischaemic and non-ischaemic HF.

Methods And Results: Results of quantitative analyses of (123)I-mIBG myocardial SPECT, alone and in combination with (99m)Tc tetrofosmin SPECT, were studied in 619 ischaemic (I) and 319 non-ischaemic (NI) HF subjects from the ADMIRE-HF trial. Cardiac and all-cause mortality data for 2-year follow-up were collected in the extension study (ADMIRE-HFX) and were examined in relation to extent and severity of voxel-based defects, the number of myocardial segments with significant dysinnervation (derived score ≥2), and (123)I-mIBG/(99m)Tc tetrofosmin mismatch quantitation.

Quantitative iodine-123-metaiodobenzylguanidine (MIBG) SPECT imaging in heart failure with left ventricular systolic dysfunction: Development and validation of automated procedures in conjunction with technetium-99m tetrofosmin myocardial perfusion SPECT.

Background: The purpose of this study was to develop and validate new approaches to quantitative MIBG myocardial SPECT imaging in heart failure (HF) subjects.

Methods And Results: Quantitative MIBG myocardial SPECT analysis methods, alone and in conjunction with 99mTc-tetrofosmin perfusion SPECT, were adapted from previously validated techniques for the analysis of SPECT and PET perfusion imaging. To account for underestimation of MIBG defect severity in subjects with global reduction in uptake, a mixed reference database based on planar heart/mediastinum (H/M) ratio categories was used.

Initial Evaluation of (99m)Tc(CO)3(ASMA) as a Renal Tracer in Healthy Human Volunteers.

Purpose: Preclinical studies in rats showed that two of (99m)Tc(CO)3(ASMA) isomers (rac- and L-ASMA) had pharmacokinetic properties equivalent to that of (131)I-OIH, the radiopharmaceutical standard for the measurement of effective renal plasma flow. The aim of this study was to evaluate the pharmacokinetics of (99m)Tc(CO)3(ASMA) isomers in healthy human subjects.

Methods: Three ASMA ligands (rac-, L- and D-ASMA) were labeled with (99m)Tc(CO)3 using an IsoLink kit (Covidien), and each formed (99m)Tc(CO)3(ASMA) tracer was co-injected with (131)I-OIH into healthy human subjects followed by sequential imaging, plasma clearance measurements and timed urine collection.

I-123 mIBG and Tc-99m myocardial SPECT imaging to predict inducibility of ventricular arrhythmia on electrophysiology testing: a retrospective analysis.

Objectives: The purpose of this study is to assess mIBG uptake in scar border zone and its relation with ventricular arrhythmia (VA) inducibility on electrophysiology (EP) testing using I-123 mIBG SPECT and resting Tc-99m SPECT myocardial perfusion imaging (MPI).

Methods: Forty-seven patients from a previous clinical trial were retrospectively analyzed. These patients underwent I-123 mIBG and resting Tc-99m tetrofosmin SPECT, and EP testing.

Diagnostic performance of low-dose rest/stress Tc-99m tetrofosmin myocardial perfusion SPECT using the 530c CZT camera: quantitative vs visual analysis.

Background: We set out to develop normal databases and prospectively validate abnormality criteria for a low-dose Tc-99m tetrofosmin myocardial perfusion SPECT protocol using the 530c CZT camera.

Methods: All patients received 6 mCi rest/20 mCi stress doses of Tc-99m tetrofosmin. Rest and stress images were obtained over 7-9 and 5-7 minutes according to the chest size.

Automatic detection of left and right ventricles from CTA enables efficient alignment of anatomy with myocardial perfusion data.

Background: Accurate alignment between cardiac CT angiographic studies (CTA) and nuclear perfusion images is crucial for improved diagnosis of coronary artery disease. This study evaluated in an animal model the accuracy of a CTA fully automated biventricular segmentation algorithm, a necessary step for automatic and thus efficient PET/CT alignment.

Methods And Results: Twelve pigs with acute infarcts were imaged using Rb-82 PET and 64-slice CTA.

Impact of age on myocardial uptake of ¹²³I-mIBG in older adult subjects without coronary heart disease.

Background: The purpose of this study was to examine the relationship between myocardial uptake of (123)I-mIBG and age in older normal adult subjects.

Methods: 94 subjects (age 29-82, mean 58.5) without coronary heart disease were studied.

Reference values for renal size obtained from MAG3 scintigraphy.

Purpose: The purposes of this study were to establish reference values for renal size determined from 99mTc-MAG3 renal scintigraphy and to derive regression equations to predict normal limits.

Methods: The study population consisted of 106 subjects evaluated for kidney donation who underwent 99mTc-MAG3 renal scintigraphy. Renal length, width, and area were determined from the pixel length and area of whole-kidney regions of interest and correlated with patient sex, height, weight, body mass index, and body surface area (BSA).

An automatic alignment tool to improve repeatability of left ventricular function and dyssynchrony parameters in serial gated myocardial perfusion SPECT studies.

Objective: Left ventricular (LV) function and dyssynchrony parameters measured from serial gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) using blinded processing had a poorer repeatability than when manual side-by-side processing was used. The objective of this study was to validate whether an automatic alignment tool can reduce the variability of LV function and dyssynchrony parameters in serial gated SPECT MPI.

Methods: Thirty patients who had undergone serial gated SPECT MPI were prospectively enrolled in this study.