Doppler flow phantom failure detection by combining empirical mode decomposition and independent component analysis with short time Fourier transform

<p class="Abstract">Nowadays, objective protocols and criteria for the monitoring of phantoms failures are still lacking in literature, despite their technical limitations. In such a context, the present work aims at providing an improvement of a previously proposed method for the Doppler flow phantom failures detection. Such failures were classified as low frequency oscillations, high velocity pulses and velocity drifts. The novel objective method, named EMoDICA-STFT, is based on the combined application of the Empirical Mode Decomposition (EMD), Independent Component Analysis (ICA) and Short Time Fourier Transform (STFT) techniques on Pulsed Wave (PW) Doppler spectrograms. After a first series of simulations and the determination of adaptive thresholds, phantom failures were detected on real PW spectrograms through the EMoDICA-STFT method. Data were acquired from two flow phantom models set at five flow regimes, through a single ultrasound (US) diagnostic system equipped with a linear, a convex and a phased array probe, as well as with two configuration settings. Despite the promising outcomes, further studies should be carried out on a greater number of Doppler phantoms and US systems as well as including an in-depth investigation of the proposed method uncertainty.</p>

Venogenic Erectile Dysfunction: Diagnosis on Computed Tomography Cavernosography and Endovascular Treatment Using An Anterograde Access via Deep Dorsal Penile Vein

Background The underlying etiologies of erectile dysfunction may be manifold. Among them, vasculogenic etiologies are of increasing relevance and are not strictly limited to the elderly population. According to recent study, venogenic erectile dysfunction appears to be even more relevant than arteriogenic erectile dysfunction. Venogenic erectile dysfunction due to venous leakage causes insufficient penile blood retention. Proper diagnosis of venous leakage should include both color Doppler flow analysis and computed tomography cavernosography for adequate patient selection and treatment planning. Besides surgical ligation of penile draining veins, endovascular treatment methods may demonstrate more promising results. Especially endovascular embolization of venous leakage using an anterograde access via deep dorsal penile veins appears to be more beneficial for patients’ clinical outcome and awareness of this technique should be raised among endovascular interventionalists. Case presentation A 47-year-old man was diagnosed with venogenic erectile dysfunction due to venous leakage on color Doppler flow analysis and computed tomography cavernosography. He did not respond to PDE-5-inhibitors. This patient demonstrated major venous leakage of paired deep dorsal penile veins via periprostatic veins and internal pudendal veins draining into both iliohypogastric veins. This patient’s venous leak was treated with endovascular embolization using an anterograde access via deep dorsal penile veins. Conclusion In patients with erectile dysfunction due to venous leakage embolization using an anterograde access via deep dorsal penile veins is a safe non-invasive endovascular treatment option. A wider use of this technique may contribute not only to improved patient health but also to homogenization of future study results.

Relationship of Laser-Doppler-Flow and coronary perfusion and a concise update on the importance of coronary microcirculation in donor heart machine perfusion

BACKGROUND: Machine perfusion (MP) is a novel method for donor heart preservation. The coronary microvascular function is important for the transplantation outcome. However, current research on MP in heart transplantation focuses mainly on contractile function. OBJECTIVE: We aim to present the application of Laser-Doppler-Flowmetry to investigate coronary microvascular function during MP. Furthermore, we will discuss the importance of microcirculation monitoring for perfusion-associated studies in HTx research. METHODS: Porcine hearts were cardioplegically arrested and harvested (Control group, N = 4). In an ischemia group (N = 5), we induced global ischemia of the animal by the termination of mechanical ventilation before harvesting. All hearts were mounted on an MP system for blood perfusion. After 90 minutes, we evaluated the effect of coronary perfusion pressures from 20 to 100 mmHg while coronary laser-doppler-flow (LDF) was measured. RESULTS: Ischemic hearts showed a significantly decreased relative LDF compared to control hearts (1.07±0.06 vs. 1.47±0.15; p = 0.034). In the control group, the coronary flow was significantly lower at 100 mmHg of perfusion pressure than in the ischemia group (895±66 ml vs. 1112±32 ml; p = 0.016). CONCLUSIONS: Laser-Doppler-Flowmetry is able to reveal coronary microvascular dysfunction during machine perfusion of hearts and is therefore of substantial interest for perfusion-associated research in heart transplantation.

Use of a Pre-Trained Neural Network for Automatic Classification of Arterial Doppler Flow Waveforms: A Proof of Concept

Background: Arterial Doppler flow waveform analysis is a tool recommended for the management of lower extremity peripheral arterial disease (PAD). To standardize the waveform analysis, classifications have been proposed. Neural networks have shown a great ability to categorize data. The aim of the present study was to use an existing neural network to evaluate the potential for categorization of arterial Doppler flow waveforms according to a commonly used classification. Methods: The Pareto efficient ResNet-101 (ResNet-101) neural network was chosen to categorize 424 images of arterial Doppler flow waveforms according to the Simplified Saint-Bonnet classification. As a reference, the inter-operator variability between two trained vascular medicine physicians was also assessed. Accuracy was expressed in percentage, and agreement was assessed using Cohen’s Kappa coefficient. Results: After retraining, ResNet-101 was able to categorize waveforms with 83.7 ± 4.6% accuracy resulting in a kappa coefficient of 0.79 (0.75–0.83) (CI 95%), compared with a kappa coefficient of 0.83 (0.79–0.87) (CI 95%) between the two physicians. Conclusion: This study suggests that the use of transfer learning on a pre-trained neural network is feasible for the automatic classification of images of arterial Doppler flow waveforms.

Study of Ventricular Interdependence in Hemodialysis Patients

Background and objectivesStudy of respiratory variations in mitral valve (MV) Doppler flow in hemodialysis (HD) patients has not been investigated and normal adult referenced echocardiographic value is used as an echocardiographic reference to HD patients who have unique hemodynamic. This work aimed to study the respiratory variation in MV Doppler flow in HD patients to determine if it has a unique pattern in these patients, and to study any relation between this variation and volume-related parameters.MethodsWe conducted a prospective cohort study, carried out on 118 patients who underwent regular HD. A standard echocardiography was performed on the patients before and within 6 hs after dialysis. During quiet breathing, the transmitral spectral Doppler E wave was measured during inspiratory and expiratory phases using plethysmography breath-cycle chest-adhesive electrodes. The mathematic differences and the percent changes (ventricular interdependent; VI) in E wave were calculated pre-and post-dialysis. Post dialysis difference in the percent changes (∆ E wave % changes) was calculated as follows: pre-dialysis percent changes of E wave – post dialysis percent changes of E wave/pre dialysis percent changes E wave x 100. ResultsThe means of the mathematic differences between the MV inspiratory and expiratory E pre-and post-dialysis were 0.07 ± 0.18 m/s and 0.08 ± 0.22 m/s respectively with an insignificant difference between both phases; p = 0.337. Meanwhile, the means of the percent variation in the MV inspiratory and expiratory E pre-and post-dialysis were 56 ± 7 % and 44 ± 1.1 % respectively, with a significant reduction after dialysis; P = 0.000. Spearman correlation showed a significant positive correlation between post- dialysis ∆ E wave % change and post-dialysis % change of weight (r = 0.318; P = 0.000). Moreover, post- dialysis % change of weight and post- dialysis % changes of most other volume-related variable were independent predictors of post- dialysis ∆ E wave % in HD patients. ConclusionThe pre- and post- dialysis respiratory changes in the MV E wave in HD patients were higher than the normal adult referenced values. This marked variation could be explained by the unique overloading condition and could explain the LV diastolic dysfunction and the unexplained pulmonary hypertension in HD patients.

Prenatal Percutaneous Fetoscopic Laser Photocoagulation of Chorioangioma: Report of Two Cases and Review of the Literature

<b><i>Introduction:</i></b> In Doppler flow diagnosis of a large placental chorioangioma with vascularization, there may be fetal consequences as cardiac output failure and polyhydramnios. Prenatal percutaneous fetoscopic laser photocoagulation of chorioangioma is a therapeutic option. First, we present 2 cases of chorioangioma treated by fetoscopic laser photocoagulation. Second, we conducted a narrative review to identify all reported cases of chorioangioma treated by fetoscopic laser photocoagulation. <b><i>Case Presentation:</i></b> Case 1 presented a chorioangioma measuring 48 × 36 × 42 mm, and the Doppler flow study showed vascularization with a high flow rate. The fetus showed dilatation of the right cardiac chambers, moderate tricuspid insufficiency, normal Doppler indices, and polyhydramnios. Case 2 presented a chorioangioma measuring 58 × 36 × 31 mm associated with polyhydramnios and elevated peak systolic velocity of the middle cerebral artery at 49 cm/s, that is, 1.65 MoM. The procedure was performed at 22⁺² and 23⁺⁵ WG for both cases. Photocoagulation of the chorioangioma vessels was performed first on the small superficial vessels (capillaries) and then on the feeding vessels (artery first and then vein), until complete cessation of blood flow on ultrasound. Successful devascularization was achieved when flow within the chorioangioma’s feeding vessels was no longer visualized on intraoperative ultrasound examination using Doppler flow. The ultrasound follow-up showed complete cessation of blood flow in the chorioangioma, normalization of fetal signs, and normal fetal growth in both cases. In case 1, a 2,350-g boy was delivered vaginally after spontaneous labor at 33⁺⁶ WG. In case 2, a 2,700-g boy was delivered vaginally after spontaneous labor at 39⁺² WG. Neonatal findings were normal, and the outcome at 1 year was normal for both children. <b><i>Conclusion:</i></b> Prenatal percutaneous fetoscopic laser photocoagulation improves survival in large chorioangioma, despite a risk of fetal death in utero.