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A fast scheme for renal microvascular perfusion functional imaging: Assessed by an imaging quality evaluation model
摘要： Purpose: This study aimed to develop a fast scheme of multiparametric perfusion functional imaging (PFI) based on dynamic contrast-enhanced ultrasound (DCEUS) for assessing renal microvascular hemodynamics. Method: The flow process in the DCEUS-based PFI was modified step-by-step to improve its operational efficiency, which was validated through in vivo renal perfusion experiments. A multiparametric model with a comprehensive coefficient of imaging quality (CIQ) was then built on four terms of the average information entropy, contrast, gray, and noise coefficient of PFIs to evaluate the sacrifice of imaging quality during modifications of DCEUS-based PFI. Results: The multiparametric model successfully evaluated modifications of DCEUS-based PFI from multiple perspectives (R2 = 0.73, P < 0.01). Compared with the raw scheme in the renal sagittal and coronal planes, the fast PFI scheme significantly improved its operational efficiency by 62.82 ± 1.07% (P < 0.01) and the nine PFIs simultaneously maintained a similar CIQ of 0.26 ± 0.06. Conclusions: The inhomogeneous hemodynamic distributions with a ring-like feature in the renal microvasculature were accurately and efficiently characterized by the fast PFI scheme. The fast PFI scheme can be applied for early diagnosis, follow-up evaluation and monitoring treatment of chronic kidney disease.
关键词： modification,coefficient of imaging quality,perfusion functional imaging,multiparametric model,dynamic contrast-enhanced ultrasound
更新于2025-09-23 15:22:29
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Quantitative assessment of microperfusion by indocyanine green angiography in kidney transplantation resembles chronic morphological changes in kidney specimens
摘要： Indocyanine green fluorescence angiography enables a quantitative real-time perfusion assessment in kidney transplantation. The results of intraoperative microperfusion of the kidney allograft were compared to the renal chronicity score in pre-transplantation kidney biopsy specimens. The intrarenal resistance index was calculated by duplex sonography as a method of reference. Seventy-seven patients with end stage renal disease undergoing kidney transplantation were prospectively included in two centers. Correlation analysis of chronic changes in kidney biopsy specimens and the ingress of ICG fluorescence signal were investigated. The results yielded a significantly negative correlation for the renal chronicity (r= -0.294, p=0.017) as well as the intestinal fibrosis and tubular atrophy score (r=-0.328, p=0.007). There was a significant inverse relationship between the ingress and the mean RI values of the upper pole of the kidney. In summary, fluorescence angiography reflects preexisting morphological changes of the renal cortex. ICG angiography may serve as an alternative method for the assessment of microperfusion of the allograft.
关键词： kidney transplantation,indocyanine green,kidney specimen,graft perfusion
更新于2025-09-23 15:22:29
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Using blood flow pulsatility to improve the accuracy of laser speckle contrast imaging in the assessment of burns
摘要： Objectives: Measurement of perfusion is an established method to evaluate the depth of burns. >48 h after injury. The aim of the study was to investigate if measurement of blood flow pulsatility, combined with perfusion measurement, can improve early assessment of burn depth using laser speckle contrast imaging (LSCI). Methods: Perfusion and pulsatility were measured with LSCI in 187 regions of interest in 32 patients, between 0 and 5 days after injury. The reproducibility of pulsatility was tested for recording durations between 1 and 12 s. The most reproducible duration was chosen, and receiver operator characteristics were created to find suitable pulsatility cut-offs to predict surgical need. Results: A measurement duration of 8 s resulted in a good reproducibility of the pulsatility (% CV: 15.9%). Longer measurement durations resulted in a small improvement of the accuracy of the assessment. A pulsatility of <1.45 (Perfusion Units)2 on day 0–2 after injury predicted surgical need with a sensitivity of 100% (95% CI: 83.2–100%), specificity of 100% (95% CI: 95.2–100%), a positive predictive value of 100%, and a negative predictive value of 100%. Pulsatility was not significantly different when comparing measurements done day 0–2 to day 3–5. Perfusion was however significantly higher day 3–5 compared to day 0–2 for wounds healing within 3 weeks. Conclusion: Measurement of pulsatility improves the accuracy of the assessment of burns with LSCI and makes it possible to predict the need for surgery during day 0–2 after injury with a high accuracy.
关键词： Pulsatility,Burn severity,Scalds,Laser speckle contrast imaging,Perfusion,Burn assessment
更新于2025-09-23 15:21:01
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Cardiac Computed Tomography 2.0
摘要： Computed tomography angiography (CTA) is now an established diagnostic option for patients with chest pain. It is a safe alternative to functional testing, provides diagnostic certainty, is a good gatekeeper for downstream invasive angiography, and increases the diagnostic yield when invasive angiography is eventually needed. CTA-driven care is associated with more relief of angina and generates optimal medical therapy associated with reduced death and myocardial infarction. However, CT angiography can lead to more cardiac catheterizations as well as more coronary revascularization. CTA shows good sensitivity, but also suffers from suboptimal specificity; thus, one cannot be sure, lacking other functional test results, that more revascularization procedures are necessary or beneficial compared to operating on lesions with demonstrated ischemia.
关键词： Fractional Flow Reserve,Myocardial Perfusion Imaging,Cardiac Computed Tomography,Coronary Artery Disease,CT Angiography
更新于2025-09-23 15:21:01
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Early Detection of Cerebral Infarction With Middle Cerebral Artery Occlusion With Functional Near-Infrared Spectroscopy: A Pilot Study
摘要： Background: NIRSIT, a functional near-infrared spectroscopy (fNIRS) device with 204 channels, can measure oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR) in non-pulsatile blood ?ow non-invasively using the absorption difference between HbO2 and HbR at a wavelength of 700–1,000 nm and can display the perfusion status in real time. Objective: We applied NIRSIT to patients with stroke to evaluate the usefulness of NIRSIT as an fNIRS device for the early detection of stroke. Methods: We performed a prospective pilot study in an emergency department (ED). Adult patients who had suspected symptoms and signs of stroke within 12 h of the ?rst abnormal time and who underwent intravenous thrombolysis (IVT) or intra-arterial thrombectomy with acute middle cerebral artery (MCA) or internal carotid artery (ICA) infarction were enrolled. NIRSIT was applied to the patients before the imaging study, and the perfusion status of the brain was displayed in real time at the bedside. We compared the NIRSIT results with the mean transit time (MTT) map from perfusion computed tomography (PCT) and the time-to-peak (TTP) map from perfusion-weighted magnetic resonance imaging (PWI). Results: Six male and three female patients were enrolled, and the median age was 74 years. The most common symptom was unilateral extremity weakness (77.8%), followed by dysarthria (33.3%) and aphasia (11.1%). The median National Institutes of Health Stroke Scale (NIHSS) score was 17. All cases of MCA infarction showed different cerebral oxygen saturation values between bilateral lobes of the brain in fNIRS imaging, and these values matched the PCT and PWI results. Conclusions: The brain hemisphere with low oxygen saturation on fNIRS showed hypoperfusion on PCT or PWI. The fNIRS device could be useful in assessing the perfusion status of the brain and detecting MCA or ICA infarction in real time at the bedside.
关键词： middle cerebral artery,magnetic resonance imaging,computed tomography,perfusion,cerebral infarction
更新于2025-09-23 15:21:01
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Clinical Usefulness of 99mTc-Hexamethyl Propylene Amine Oxime Perfusion Single Photon Emission Computed Tomography for Early Phase Multiple System Atrophy
摘要： Background: Clinical diagnosis of multiple system atrophy (MSA) relays on signs and symptoms that are often difficult to identify particularly at early stage. Indeed neuropathological studies have demonstrated that Parkinson variant of MSA (MSA-P) is the first cause of misdiagnosis in a cohort of patients presenting with parkinsonian features. But accurate diagnosis of these disorders is important for deciding on treatment, appropriate advice and prognosis since atypical parkinsonian disorders are characterized by poor response to dopaminergic treatment and more rapid disease progression. Therefore, we conducted this study to investigate difference of perfusion Single Photon Emission Computed Tomography (SPECT) in patients with the early phase of MSA-P using SPM program. Methods: We recruited consecutively 21 patients with MSA-P and 48 age-matched healthy controls. All subjects underwent Tc-99m HMPAO perfusion SPECT and this perfusion images were analyzed. Results: For MSA-P, only hypoperfusion was seen in the middle frontal gyrus of left frontal lobe, superior frontal gyrus of right frontal lobe, precentral gyrus of left frontal lobe, middle frontal gyrus of right frontal lobe and precentral gyrus of right frontal lobe with respect to healthy subjects. Conclusions: We cautiously assume that perfusion SPECT may offer significant advantages compared to other imaging techniques in the assessment of neuronal degeneration in MSA-P and may help the clinician in the diagnostic characterization of patients presenting with atypical parkinsonism.
关键词： Frontal lobe,Tc-99m HMPAO perfusion SPECT,Multiple system atrophy
更新于2025-09-23 15:21:01
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Visualising improved peritoneal perfusion at lower intra-abdominal pressure by fluorescent imaging during laparoscopic surgery: A randomised controlled study
摘要： Background: Laparoscopy is the gold standard for many surgical procedures and is embraced as minimally invasive surgery in the enhanced recovery after surgery programme. Lowering intra-abdominal pressure during laparoscopy may decrease the degree of surgical injury and further enhance patient outcomes. This study aims to assess the effect of low pressure pneumoperitoneum on peritoneal perfusion during laparoscopic surgery. Materials and methods: We performed a prospective randomized intervention study in 30 adults undergoing colorectal robot assisted laparoscopic surgery at a secondary care medical center in the Netherlands between June and December 2018. A 3 minute video recording of the parietal peritoneum was made with the Da Vinci? Firefly mode following intravenous injection of 0.2 mg/kg indocyanine green at a pneumoperitoneum pressure of 8, 12 or 16 mmHg. Observers were blinded for the level of intra-abdominal pressure that was used. Fluorescent intensity in [-] over time was extracted from each video in MATLAB. Time to reach maximal fluorescent intensity (TMFI) and maximum fluorescent intensity (MFI) were compared among groups. The study was registered at clinicaltrials.gov (NCTXXXXXXXX). Results: Mean TMFI was shorter at low pressure (8 mmHg) than standard pressure (12 and 16 mmHg): 44 ± 12 versus 58 ± 18 seconds (p=0.032), respectively. Mean MFI was higher at 8 mmHg than 12 and 16 mmHg (222 ± 25 versus 188 ± 54, p=0.033). Regression analysis identified intra-abdominal pressure, mean arterial pressure and female gender as significant predictors of peritoneal perfusion. Conclusion: Low pressure pneumoperitoneum was associated with improved perfusion of the parietal peritoneum. Current available evidence supported feasibility and enhanced postoperative recovery. Future investigations should focus on optimizing factors that facilitate lower intra-abdominal pressure and explore effects on other clinically relevant patient outcomes such as anastomotic leakage and immune homeostasis.
关键词： intra-abdominal pressure,ischemia-reperfusion injury,pneumoperitoneum,perfusion,laparoscopic surgery,immune homeostasis
更新于2025-09-23 15:19:57
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The Supplementary Motor Area Responsible for Word Retrieval Decline After Acute Thalamic Stroke Revealed by Coupled SPECT and Near-Infrared Spectroscopy
摘要： Damage to the thalamus may affect cognition and language, but the underlying mechanism remains unknown. In particular, it remains a riddle why thalamic aphasia occasionally occurs and then mostly recovers to some degree. To explore the mechanism of the affected cognition and language, we used two neuroimaging techniques—single-photon emission computed tomography (SPECT), suitable for viewing the affected brain distribution after acute thalamic stroke, and functional near-infrared spectroscopy (f-NIRS), focusing on hemodynamic responses of the supplementary motor area (SMA) responsible for speech production in conjunction with the frontal aslant tract (FAT) pathway. SPECT yielded common perfusion abnormalities not only in the fronto–parieto–cerebellar loop, but also in the SMA, IFG and surrounding language-relevant regions. In NIRS sessions during a phonemic verbal fluency task, we found significant word retrieval decline in acute thalamic patients relative to age-matched healthy volunteers. Further, NIRS showed strong correlation between word retrieval and posterior SMA responses. In addition, follow-up NIRS exhibited increased bilateral SMA responses linked to improving word retrieval ability. The findings suggest that cognitive dysfunction may be related to the fronto–parieto–cerebellar loop, while language dysfunction is attributed to the SMA, IFG and language-related brain areas. SMA may contribute to the recovery of word retrieval difficulty and aphasia after thalamic stroke.
关键词： SPECT,hemodynamic response,perfusion,verbal fluency test,thalamic aphasia,FAT: frontal aslant tract,cerebro-cerebellar diaschisis,functional near-infrared spectroscopy (f-NIRS)
更新于2025-09-23 15:19:57
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Extending the Use of Coronary Calcium Scanning to Clinical Rather Than Just Screening Populations
摘要： Twenty-five years after its initial development, coronary artery calcium (CAC) scanning has become a relatively inexpensive test that has been extensively validated as a potent noninvasive means for assessing the burden of coronary atherosclerosis in asymptomatic individuals. A proportional relationship between the magnitude of CAC abnormality and the frequency of subsequent cardiac events over long-term follow-up has been consistently demonstrated, including observations from large patient and population-based cohorts.1–3 Incremental prognostic value over standard clinical assessments including the Framingham Risk Score and other scores of global risk has also been consistently reported.3,4 Consequently, the application of CAC scanning for assessing asymptomatic patients with intermediate clinical risk has now become part of clinical guidelines.5,6
关键词： tomography, emission-computed, single-photon,myocardial perfusion imaging,coronary angiography,atherosclerosis,Editorials,coronary artery disease
更新于2025-09-19 17:15:36
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A learning-based automatic segmentation and quantification method on left ventricle in gated myocardial perfusion SPECT imaging: A feasibility study
摘要： Background. The performance of left ventricular (LV) functional assessment using gated myocardial perfusion SPECT (MPS) relies on the accuracy of segmentation. Current methods require manual adjustments that are tedious and subjective. We propose a novel machine-learning-based method to automatically segment LV myocardium and measure its volume in gated MPS imaging without human intervention. Methods. We used an end-to-end fully convolutional neural network to segment LV myocardium by delineating its endocardial and epicardial surface. A novel compound loss function, which encourages similarity and penalizes discrepancy between prediction and training dataset, is utilized in training stage to achieve excellent performance. We retrospectively investigated 32 normal patients and 24 abnormal patients, whose LV myocardial contours automatically segmented by our method were compared with those delineated by physicians as the ground truth. Results. The results of our method demonstrated very good agreement with the ground truth. The average DSC metrics and Hausdorff distance of the contours delineated by our method are larger than 0.900 and less than 1 cm, respectively, among all 32 + 24 patients of all phases. The correlation coefficient of the LV myocardium volume between ground truth and our results is 0.910 ± 0.061 (P < 0.001), and the mean relative error of LV myocardium volume is -1.09 ± 3.66%. Conclusion. These results strongly indicate the feasibility of our method in accurately quantifying LV myocardium volume change over the cardiac cycle. The learning-based segmentation method in gated MPS imaging has great promise for clinical use.
关键词： Myocardial perfusion,machine learning,segmentation,SPECT
更新于2025-09-19 17:15:36