Vascular Flow Patterns Research Articles

Quantitative Evaluation of Hemodynamic Changes After Multiple Intracranial Aneurysms Occlusion Using Computational Fluid Dynamics

OBJECTIVEMultiple intracranial aneurysms (MIA) are prevalent. This study conducted hemodynamic calculations on MIA to analyze the effects of occlusion of the internal carotid artery (ICA) and middle cerebral artery (MCA) aneurysms on the hemodynamics of other arteries, as well as the issue of the treatment order for these aneurysms. METHODSThe models of 9 patients with MIA were selected for the study. A computational fluid dynamics model combining 1-D and 3-D was used to obtain the vascular flow pattern and wall pressure. RESULTSThere was increased pressure at the MCA and Anterior Cerebral Artery (ACA) after occlusion of the aneurysm at the ICA. However, the pressure at the ICA has hardly changed after the aneurysm occlusion at the MCA. Occlusion of the aneurysm of different sizes at the MCA had almost no impact on the pressure at the ICA and ACA. For small aneurysm, the pressure of the ACA and MCA increases with decreasing size of the aneurysm at the ICA. After occlusion of a large aneurysm at the ICA, the impact on the pressure of the ACA and MCA is almost the same as after occlusion of a medium-sized aneurysm. CONCLUSIONSIf the treatment order of ICA and MCA aneurysms cannot be determined based on patient factors and aneurysm characteristics, the MCA aneurysm should be treated as a priority.

2D versus 3D comparison of angiographic imaging biomarkers using computational fluid dynamics simulations of contrast injections.

Quantitative angiography (QAngio) may provide hemodynamic information during neurointerventional procedures through imaging biomarkers related to contrast flow. The standard clinical implementation of QAngio is limited by projection imaging: analysis of contrast motion within complex 3D geometries is restricted to 1-2 projection views, truncating the potential wealth of imaging biomarkers related to disease progression or efficacy of treatment. To understand the limitations of 2D biomarkers, we propose the use of in-silico contrast distributions to investigate the potential benefits of 3D-QAngio within the context of neurovascular hemodynamics. Ground-truth in-silico contrast distributions were generated in two patient-specific intracranial aneurysm models, accounting for the physical interactions of contrast media and blood. A short bolus of contrast was utilized to obtain full a wash-in/ wash-out cycle within the aneurysm ROI. Simulated angiograms mimicking clinical cone-beam CT (CBCT) acquisitions were then generated, and volumetric contrast distributions were reconstructed to analyze bulk contrast flow. The ground-truth 3D-CFD, reconstructed 3D-CBCT-DSA, and 2D-DSA projections were used to extract QAngio parameters related to contrast time dilution curves, such as area under the curve (AUC), peak height (PH), mean-transit-time (MTT), time-to-peak (TTP), and time to arrival (TTA). An initial comparison of quantitative flow parameters in both 2D and 3D, in a smaller and larger aneurysm, indicated that 3D-QAngio can provide a good description of bulk flow characteristics (TTA, TTP, MTT), but recovery of integral parameters (PH, AUC) aneurysms is limited. Nonetheless, incorporation of 3D-QAngio methods may provide additional insight into our understanding of abnormal vascular flow patterns.

Physiological fetal vascular shunts and failure to regress: what the radiologist needs to know.

The fetal circulation is characterized by the presence of three physiological vascular shunts - the ductus arteriosus, the foramen ovale and the ductus venosus. Acting in concert, these shunts preferentially stream blood flow in a pattern that maximizes efficiency of blood oxygenation by the maternofetal unit. Shortly following the transition to extrauterine life, a quick and predetermined succession of events results in closure of these embryological structures with consequent establishment of postnatal vascular flow patterns. While this transition is often seamless, the physiological shunts of the fetus occasionally fail to regress. Such failure to regress can occur in isolation or in association with other congenital malformations. This failed regression challenges the circulatory physiology of the neonate and might have implications for the optimum functioning of several organ systems. When symptomatic, these shunts are treated. Interventions, when undertaken, might be medical, endovascular or surgical. The radiologist's role continues to expand in the assessment of these shunts, in providing a roadmap for treatment and in prompt identification of treatment-related complications. This review is to familiarize radiologists with the embryology, pre- and post-treatment imaging appearances, and associated complications of persistent fetal vascular shunts.

POCUS in Intensive Care Nephrology.

Acute kidney injury (AKI) is a significant problem for patients admitted to the intensive care unit (ICU), both due to the high incidence and associated mortality with rates of AKI requiring renal replacement therapy (RRT) of over 5%, and mortality rates with AKI of over 60% 1, 2.Ultrasound can be used to identify those at risk for AKI and assist with AKI management. Risk factors for AKI in the ICU not only include hypoperfusion but also venous congestion and volume overload. Volume overload and vascular congestion are associated with multi-organ dysfunction and worse renal outcomes. Daily and overall fluid balance, daily weights, and physical examination for edema can be inaccurate and belie true systemic venous pressure 3, 4, 5. Bedside ultrasound allows providers to evaluate vascular flow patterns and obtain a more reliable evaluation of volume status to guide and individualize therapies. Cardiac, lung, and vascular patterns on ultrasound can identify preload responsiveness, which should be assessed to safely manage ongoing fluid resuscitation and assess for signs of fluid intolerance. Here we present an overview in the use of point of care ultrasound with particular emphasis on nephro-centric strategies, namely in the identification of the type of renal injury, renal vascular flow assessment, the static measure of volume status, as well as dynamic evaluation for volume optimization in critically ill patients.

Vascular morphology and blood flow signatures for differential artery-vein analysis in optical coherence tomography of the retina.

Differential artery-vein (AV) analysis is essential for retinal study, disease detection, and treatment assessment. This study is to characterize vascular reflectance profiles and blood flow patterns of retinal artery and vein systems in optical coherence tomography (OCT) and OCT angiography (OCTA), and establish them as robust signatures for objective AV classification. A custom designed OCT was employed for three-dimensional (3D) imaging of mouse retina, and corresponding OCTA was reconstructed. Radially resliced OCT B-scans revealed two, i.e. top and bottom, hyperreflective wall boundaries in retinal arteries, while these wall boundaries were absent in OCT of retinal veins. Additional OCTA analysis consistently displayed a layered speckle distribution in the vein, which may indicate the venous laminar flow. These OCT and OCTA differences offer unique signatures for objective AV classification in OCT and OCTA.

Adrenal Vascular Changes in COVID-19 Autopsies.

To the Editor.—For the past 2 months, New York City has been the epicenter of the ongoing pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus). The disease (coronavirus disease 2019 [COVID-19]) most acutely and severely affects the lungs, requiring mechanical ventilation in a subset of cases. Other organs, including the heart, kidneys, liver, and gastrointestinal tract, can also be involved. The pathophysiology and the extent of multiorgan involvement is poorly understood. We report pathological findings in the adrenal glands of the first 5 postmortem examinations of patients with COVID-19 diagnosed on clinical grounds with confirmatory real-time polymerase chain reaction testing of nasopharyngeal swab. Two patients were brought to the emergency room in cardiac arrest and could not be resuscitated. Three were briefly hospitalized, 2 for 24 hours and 1 for 72 hours. There were 4 males and 1 female, ranging from 59 to 90 years of age and with the following co-morbidities: hypertension (5 of 5), diabetes (3 of 5), ischemic cardiomyopathy (3 of 5), chronic lung disease (2 of 5, 1 with chronic obstructive pulmonary disease and 1 with interstitial lung disease), prostate carcinoma (2 of 5), and recent spinal surgery (1 of 5). Blood cultures were negative in the 3 patients tested. On microscopic examination, acute fibrinoid necrosis of small vessels, mainly arterioles in adrenal parenchyma, adrenal capsule, and in the immediately adjacent periadrenal adipose tissue, was identified. Subendothelial vacuolization and apoptotic debris were present (Figure, A–C). No significant inflammation, adrenal parenchymal infarcts, or thrombi were appreciated. The vascular pathology was disproportionately conspicuous in adrenal and not as easily identified in other organs examined.Fibrinoid necrosis describes vessel wall necrosis with fibrin and serum protein accumulation conveying an eosinophilic amorphous appearance on histology. With Masson's trichrome stain, the amorphous fibrinoid material is red, unlike collagen that stains blue (Figure, D). Arteriolar hyalinosis is another term used to describe the accumulation of pink amorphous material in vessel walls. This is thought to relate to hypertension, but is not typically associated with vessel necrosis and endothelial apoptosis. Hyalinosis may explain some of the histopathology; however, many of the vessels we observed were either necrotic or associated with apoptosis. It is unclear if the adrenal vasculopathy is because of hypoxia, abnormal vascular reaction and blood flow patterns, direct viral cytopathic effect, an immune-mediated injury, or a combination of events. Acute fibrinoid necrosis is classically described in malignant hypertension (first by Volhard and Fahr1 in 1914), mainly in kidneys, and in immune-mediated vasculitides. While SARS-CoV-2 infection seems to more severely affect patients with a history of hypertension,2 most critically ill patients with COVID-19 need vasopressors for persistent hypotension.3 Two of 3 hospitalized patients described had recorded high blood pressure values and 1 was hypotensive on arrival. Localized fibrinoid necrosis is also mentioned in a report of pathological findings in SARS virus infection.4 SARS-CoV-2 virus gains entry to the cell via the angiotensin-converting enzyme 2 receptor,5 which is most abundant in lung alveolar cells, but also present in endothelia and other tissues, providing a possible mechanism for vascular injury.6Adrenal hormones are involved in modulating inflammatory responses7 and adrenal gland dysfunction has been described in patients with community-acquired pneumonia.8In general, adrenal function is not routinely assessed in an intensive care unit setting. The most common indication for corticosteroid administration in an intensive care unit is refractory hemodynamic shock. According to several critical care societies, acute respiratory distress syndrome management can include corticosteroids, as they may decrease the time on a ventilator and reduce mortality.9 Corticosteroids are also administered if there is suspicion of adrenal insufficiency or if they are indicated because of an underlying condition. Currently, the World Health Organization and major critical care and infectious diseases associations advise against routine corticosteroid use in COVID-19 patients, mainly out of concern for slowing viral clearance. However, early reports from China and Europe suggested that corticosteroids are useful in severe COVID-19 and some experts posit that severe cytokine release syndrome seen in some patients warrants the use of corticosteroids or other targeted immunosuppressants.9–12It is interesting to consider that adrenal insufficiency secondary to the vasculopathy described here may contribute to the cytokine storm observed in patients with severe COVID-19. Clinical studies to further assess adrenal function in COVID-19 may help in understanding the pathogenesis of disease in severely affected patients and hopefully lead to therapeutic protocols that may rescue an increased number of patients.

Novel modalities for the diagnosis of cardiac surgery associated acute kidney injury : a narrative review of the literature

Acute kidney injury (AKI) is a common complication post cardiac surgery and increases mortality during hospitalisation fivefold. If present, it is an independent risk factor for progression to chronic kidney disease. When renal replacement therapy (RRT) is required, it carries a 50% mortality rate for cardiac surgery associated (CSA) AKI. Given the dynamic nature of CSA AKI, it is imperative to implement preventative and management strategies to: prevent or limit ischaemia; reduce systemic inflammation; modify amenable pre- and perioperative risk factors; and address nutritional and fluid status at the pre- intra- and postoperative stages. Conventional modalities in the diagnosis of AKI have proven ineffectual in the timely diagnosis, and rely mostly on nonspecific biometric parameters, namely a rise in serum creatinine, and a decrease in urine output. Novel biomarkers have promoted new ideas in the search for more effective, precise and reproducible tools to aid diagnosis. In addition, ultrasonic tools for renal, hepatic and portal vascular flow patterns using Duplex Doppler for venous flow parameters, together with renal arterial resistive index, have been used as novel predictors of perioperative AKI. Although these parameters require further investigation, Duplex Doppler of the renal, hepatic, portal and cardiac systems appear to have promising results in the early detection of AKI.

The improvement of the shear stress and oscillatory shear index of coronary arteries during Enhanced External Counterpulsation in patients with coronary heart disease.

Enhanced External Counterpulsation (EECP) can chronically relieve ischemic chest pain and improve the prognosis of coronary heart disease (CHD). Despite its role in mitigating heart complications, EECP and the mechanisms behind its therapeutic nature, such as its effects on blood flow hemodynamics, are still not fully understood. This study aims to elucidate the effect of EECP on significant hemodynamic parameters in the coronary arterial tree. A finite volume method was used in conjunction with the inlet pressure wave (surrogated by the measured aortic pressure) before and during EECP and outlet flow resistance, assuming the blood as newtonian fluid. The time-average wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. Regardless of the degree of vascular stenosis, hemodynamic conditions and flow patterns could be improved during EECP. In comparison with the original tree, the tree with a severe stenosis (75% area stenosis) demonstrated more significant improvement in hemodynamic conditions and flow patterns during EECP, with surface area ratio of TAWSS risk area (SAR-TAWSS) reduced from 12.3% to 6.7% (vs. SAR-TAWSS reduced from 7.2% to 5.6% in the original tree) and surface area ratio of OSI risk area (SAR-OSI) reduced from 6.8% to 2.5% (vs. SAR-OSI of both 0% before and during EECP in the original tree because of mild stenosis). Moreover, it was also shown that small ratio of diastolic pressure (D) and systolic pressure (S) (D/S) could only improve the hemodynamic condition mildly. The SAR-TAWSS reduction ratio significantly increased as D/S became larger. A key finding of the study was that the improvement of hemodynamic conditions along the LMCA trees during EECP became more significant with the increase of D/S and the severity degree of stenoses at the bifurcation site. These findings have important implications on EECP as adjuvant therapy before or after percutaneous coronary intervention (PCI) in patients with diffuse atherosclerosis.

Flow-regulated endothelial glycocalyx determines metastatic cancer cell activity.

Cancer metastasis and secondary tumor initiation largely depend on circulating tumor cell (CTC) and vascular endothelial cell (EC) interactions by incompletely understood mechanisms. Endothelial glycocalyx (GCX) dysfunction may play a significant role in this process. GCX structure depends on vascular flow patterns, which are irregular in tumor environments. This work presents evidence that disturbed flow (DF) induces GCX degradation, leading to CTC homing to the endothelium, a first step in secondary tumor formation. A 2-fold greater attachment of CTCs to human ECs was found to occur under DF conditions, compared to uniform flow (UF) conditions. These results corresponded to an approximately 50% decrease in wheat germ agglutinin (WGA)-labeled components of the GCX under DF conditions, vs UF conditions, with undifferentiated levels of CTC-recruiting E-selectin under DF vs UF conditions. Confirming the role of the GCX, neuraminidase induced the degradation of WGA-labeled GCX under UF cell culture conditions or in Balb/C miceand led to an over 2-fold increase in CTC attachment to ECs or Balb/C mouse lungs, respectively, compared to untreated conditions. These experiments confirm that flow-induced GCX degradation can enable metastatic CTC arrest. This work, therefore, provides new insight into pathways of secondary tumor formation.

Is Vertebral artery compression a cause of cervicogenic vertigo in cervical spondylosis patients? A color doppler ultrasound correlation study

Introduction: Pathophysiology of vertigo in patients having neck pain is not well understood, and many theories have been postulated. Cervical spondylitis is one of the most common causes of neck pain, and these are the group of patients who often complain of vertigo. The role of vascular flow alteration in these patients in causing vertigo is under investigation. We intended to study the vascular flow pattern in the vertebral circulation using color Doppler ultrasound in these patients and compare it with controls. Material and Methods: Fifteen cases and 11 controls were evaluated using color Doppler ultrasound. All these patients were evaluated in detail by the Ear, Nose, Throat and the orthopedics department. The statistical analysis was done by IBP SPSS version 22 software. Independent t-test was performed to compare the case and control groups. Results: The mean intimal thickness of common carotid artery of cases was significantly less than the controls (0.35 mm vs. 0.51 mm for the right common carotid artery and 0.38 mm vs. 0.54 mm for the left common carotid artery, P

Vascular flow on doppler sonography may not be a valid characteristic to distinguish colloid nodules from papillary thyroid carcinoma even when accounting for nodular size.

The purpose of this study was to test the hypothesis that there is no significant difference in vascular flow patterns between cytopathologically-proven colloid nodules and papillary thyroid carcinoma (PTC) even when adjusting for nodule size. Doppler vascular flow patterns in 200 colloid nodules and 166 nodules with PTC were retrospective reviewed independently by 2 neuroradiologists blinded to the cytopathological results. Absence of vascular flow, perinodular and/or intranodular flow, and diffuse vascular flow were recorded. The vascular flow patterns were compared without (Fisher exact test) and with (Kruskal-Wallis test) an adjustment for nodular size. Using the most common flow pattern as the reference group, multiple logistic regression was used to compare the flow patterns. Sample skewness was calculated to determine degree of symmetry of the size distribution for each vascular flow category. No significant difference was found in the tested vascular flow patterns between colloid nodules and PTC both without and with an adjustment for nodular size (P>0.05). Intranodular flow only was the largest group (n=111/366) and used as the reference for multiple logistic regression. No significant difference was noted between the vascular flow patterns (P>0.05). Sample skewness showed that nodules were generally smaller in size with outliers of larger size on the opposite end of the spectrum. Independent of nodule size the absence or presence of vascular flow is not significantly different between colloid nodules and PTC. Therefore, vascular flow may not be useful in distinguishing between colloid nodules and PTC.

Multicenter Prospective Study of Color Doppler Ultrasound for Breast Masses: Utility of Our Color Doppler Method

The use of color Doppler ultrasound (CD) for distinguishing between benign and malignant breast lesions remains controversial. This study (JABTS BC-04 study) was aimed at confirming the usefulness of our CD diagnostic criteria. We evaluated ultrasound images of 1408 solid breast masses from 16 institutions in Japan (malignant: 839, benign: 569). Multivariate analysis indicated that vascularity (amount of blood flow), vascular flow pattern (“surrounding marginal flow” or “penetrating flow”) and the incident angle of penetrating flow were significant findings for distinguishing between benign and malignant lesions. However, the sensitivity and specificity of B-mode alone did not improve significantly with CD addition (97.6% → 97.9%, 38.3% → 41.5%, respectively). We explored the causes of these negative results and found that age should have been considered when evaluating vascularity. Simulation experiments suggested that specificity is significantly improved when age is taken into consideration (38.3% → 46.0%, p < 0.001) and we thereby improved our diagnostic criteria.

Acute Tachycardia Increases Aortic Distensibility, but Reduces Total Arterial Compliance Up to a Moderate Heart Rate.

Background: The differential effects of rapid cardiac pacing on small and large vessels have not been well-established. The objective of this study was to investigate the effect of pacing-induced acute tachycardia on hemodynamics and arterial stiffness.Methods: The pressure and flow waves in ascending aorta and femoral artery of six domestic swine were recorded simultaneously at baseline and heart rates (HR) of 135 and 155 beats per minutes (bpm) and analyzed by the models of Windkessel and Womersley types. Accordingly, the flow waves were simultaneously measured at carotid and femoral arteries to quantify aortic pulse wave velocity (PWV). The arterial distensibility was identified in small branches of coronary, carotid and femoral arteries with diameters of 300–600 μm by ex vivo experiments.Results: The rapid pacing in HR up to 135 bpm reduced the total arterial compliance, stroke volume, systemic pulse pressure, and central systolic pressure by 36 ± 17, 38 ± 26, 29 ± 16, and 23 ± 12%, respectively, despite no statistical difference of mean aortic pressure, cardiac output, peripheral resistance, and vascular flow patterns. The pacing also resulted in a decrease of distensibility of small muscular arteries, but an increase of aortic distensibility. Pacing from 135 to 155 bpm had negligible effects on systemic and local hemodynamics and arterial stiffness.Conclusions: There is an acute mismatch in the response of aorta and small arteries to pacing from basal HR to 135 bpm, which may have important pathological implications under chronic tachycardia conditions.

Visualizing artery-specific blood flow patterns above the circle of Willis with vessel-encoded arterial spin labeling.

PurposeTo establish the feasibility of using vessel‐encoded pseudocontinuous arterial spin labeling (VEPCASL) for noninvasive vascular territory imaging (VTI) and artery‐specific dynamic angiography of a large number of arterial branches above the circle of Willis within a clinically feasible scan time.Methods3D time‐of‐flight angiography was used to select a labeling plane and establish 7 pairs of encoding cycles. These were used for VEPCASL VTI and dynamic 2D angiography (8 min and 3 min acquisition times, respectively) in healthy volunteers, allowing the separation of signals arising from 13 arterial branches (including extracranial arteries) in postprocessing. To demonstrate the clinical potential of this approach, VEPCASL angiography was also applied in 5 patients with brain arteriovenous malformation (AVM).ResultsIn healthy volunteers, the artery‐specific filling of the vascular tree and resulting perfusion territories were well depicted. SNRs were approximately 5 times higher than those achievable with single‐artery selective methods. Blood supply to the AVMs was well visualized in all cases, showing the main feeding arteries and venous drainage.ConclusionsVEPCASL is a highly efficient method for both VTI and dynamic angiography of a large number of arterial branches, providing a comprehensive picture of vascular flow patterns and the effect on downstream tissue perfusion within an acceptable scan time. Automation of labeling plane and vessel‐encoding selection would improve robustness and efficiency, and further refinement could allow quantitative blood flow measurements to be obtained. This technique shows promise for visualizing the blood supply to lesions and collateral flow patterns.

The supraclavicular artery island flap: a salvage option for head and neck reconstruction

BackgroundSome of head and neck cancer patients are in compromised general condition after ablation surgery and chemoradiation therapy, which makes secondary free tissue transfer quite challenging. Elderly cancer patients also have some risk for microvascular surgery with lengthened general anesthesia. In those cases, the pedicled flap vascularized by supraclavicular artery could be considered as an alternative to free flap. Despite several authors have demonstrated the clinical reliability of supraclavicular artery island flap (SCAIF), to date, SCAIF has not been widely used among reconstructive surgeon. In this article, we clarified vascular flow pattern and introduce simple surgical technique of SCAIF with a literature review.Case presentationThree patients who had underwent previous neck surgery and adjuvant therapy received maxillofacial reconstruction using SCAIF. It required only a few landmarks, flap harvesting was carried out, and the elapsed time gradually decreased to 15 min with experiences. There were no remarkable morbidities in both donor and recipient sites.ConclusionSCAIF exhibited minimal anatomic variations and short learning curve of surgical techniques, which might be valuable reconstruction modality for beginning surgeon. And it can be beneficial option for the patients with vessel-depleted neck, medically compromised status for lengthened general anesthesia and failed free tissue transfer.

Development of Clinical Criteria for Functional Assessment to Predict Primary Nonfunction of High-Risk Livers Using Normothermic Machine Perfusion.

Increased use of high‐risk allografts is critical to meet the demand for liver transplantation. We aimed to identify criteria predicting viability of organs, currently declined for clinical transplantation, using functional assessment during normothermic machine perfusion (NMP). Twelve discarded human livers were subjected to NMP following static cold storage. Livers were perfused with a packed red cell–based fluid at 37°C for 6 hours. Multilevel statistical models for repeated measures were employed to investigate the trend of perfusate blood gas profiles and vascular flow characteristics over time and the effect of lactate‐clearing (LC) and non‐lactate‐clearing (non‐LC) ability of the livers. The relationship of lactate clearance capability with bile production and histological and molecular findings were also examined. After 2 hours of perfusion, median lactate concentrations were 3.0 and 14.6 mmol/L in the LC and non‐LC groups, respectively. LC livers produced more bile and maintained a stable perfusate pH and vascular flow >150 and 500 mL/minute through the hepatic artery and portal vein, respectively. Histology revealed discrepancies between subjectively discarded livers compared with objective findings. There were minimal morphological changes in the LC group, whereas non‐LC livers often showed hepatocellular injury and reduced glycogen deposition. Adenosine triphosphate levels in the LC group increased compared with the non‐LC livers. We propose composite viability criteria consisting of lactate clearance, pH maintenance, bile production, vascular flow patterns, and liver macroscopic appearance. These have been tested successfully in clinical transplantation. In conclusion, NMP allows an objective assessment of liver function that may reduce the risk and permit use of currently unused high‐risk livers.

Diagnostic Accuracy of Doppler Ultrasonography in the Antenatal Diagnosis of Abnormal Placental Invasion Secondary to Placenta Praevia

Objective: To determine the diagnostic accuracy of Doppler Ultrasonography in a tertiary care hospital, for the antenatal diagnosis of abnormal placental invasion secondary to placenta praevia, taking operative findings of caesarean section as gold standard.&#x0D; Methods: This is a cross-sectional study carried out in the Department of Radiology, Liaquat National Hospital, Karachi, from 1st August 2013 to 31st July 2014. A total of 591 pregnant women (multipara) having placenta praevia were included in this study. The diagnosis of abnormal placental invasion was made by Doppler USG and compared with operative findings of caesarean section as gold standard. A predesigned pro forma was used to document findings. SPSS version 17 was used for all sta- tistical analysis.&#x0D; Results: Sensitivity, specificity, positive and negative predictive value as well as accuracy of Doppler ultrasonography (USG) in the detection of abnormal placental invasion was found to be 84.8%, 93.9%, 91.8%, 88.5% and 89.95%, respectively.&#x0D; Conclusion: Any persistent placenta praevia, will benefit from antenatal Doppler USG studies to identify abnormal utero-placental vascular flow patterns and these findings clearly aid in the management of this most challenging obstetric complication.

New Doppler imaging technique for assessing angiogenesis in breast tumors: correlation with immunohistochemically analyzed microvessels density.

Microvessel density (MVD) is associated with grade and prognosis in breast tumors. However, conventional color Doppler flow (CDF) imaging has been limited to represent MVD of breast tumors. To evaluate whether a new Doppler imaging technique (AngioPLUS) can represent MVD of breast tumors. The institutional review board approved this retrospective study, and patients' informed consent was waived. CDF and AngioPLUS were available in pathologically confirmed 55 breast tumors of 53 women. For each lesion, vascular flow patterns (distribution and amount) of both Doppler images were retrospectively reviewed, and MVD was measured using immunohistochemical analysis of the biopsied tissue sections. MVD was subcategorized as low or high group with reference to the median. The associations between the Doppler features and MVD were evaluated using Fisher's exact test and Student's t test. Of the 55 masses, 28 (50.9%) were benign and 27 (49.1%) were malignant. Vascular flow distribution and amount of both Doppler imaging were different between the benign and malignant lesions (CDF, P = 0.020 and P = 0.010; AngioPLUS, P = 0.002 and P = 0.005). MVD had no significant relationships with CDF features, but vascular flow distribution on AngioPLUS showed significant differences between the lesions with low and high MVD ( P = 0.020); Combined distribution was more frequent in the high MVD lesions than in the low MVD lesions (17/28, 60.7% vs. 6/27, 22.2%). Our data confirmed the correlation between a new Doppler imaging technique, AngioPLUS, and MVD. We suggest that AngioPLUS can be used for assessing MVD in breast tumors.

The Role Of High Resolution Ultrasonography To Differentiate Between Benign And Malignant Cervical Lymph Nodes In Oral Squamous Cell Carcinoma

Objectives:The purpose of the study was to evaluate the role of high resolution ultrasonography to differentiate between benign and malignant cervical lymph nodes in oral squamous cell carcinoma.Materials &amp; Methods:The study was conducted in the Department of Oral and Maxillofacial Surgery, BSMMU,Dhaka, Bangladesh, during a period of January -2010 to December - 2011. A total number of 41 patients with clinical evidence of palpable cervical lymph nodes in oral squamous cell carcinoma were evaluated with high resolution ultrasonography. To evaluate the diagnostic accuracy of high resolutionultrasonography, the high resolution ultrasonography findings were compared and correlat- ed with histopathological examination after neck dissection.Results: All patients were pre-operatively examined by palpation and high resolution ultrasonography evaluation was done.Among them 41 study subjects, on high resolution ultrasonography evaluation 23(56.09%) lymph nodes were metastatic and 18(43.90%) lymph nodes were reactive. After postop- erative excisional histopathology examination 22(53.66%) lymph nodes were metastatic and 19(46.34%) lymph nodes were reactive in nature. Correlation of vascular flow pattern with histopatho- logical diagnosis showed that central flow for benign nodes, mixed &amp; peripheral flow for malignant nodes were highly significant parameters (P&lt;0.001). High resolution ultrasonography has specificity 78.94%, sensitivity 86.36% and diagnostic accuracy of the high resolution ultrasonography was 82.92%.Conclusion: High resolution ultrasonography can plays a definite role as an adjunct to the clinical evaluation of palpable cervical lymph nodes and proves its value as an important noninvasive investi- gation procedure for differentiating between benign and malignant cervical lymph nodes in oral squa- mous cell carcinoma.Update Dent. Coll. j: 2017; 7 (2): 19-27

Automatic intraoperative estimation of blood flow direction during neurosurgical interventions.

In neurosurgery, reliable information about blood vessel anatomy and flow direction is important to identify, characterize, and avoid damage to the vasculature. Due to ultrasound Doppler angle dependencies and the complexity of the vascular architecture, clinically valuable 3-D flow direction information is currently not available. In this paper, we aim to clinically validate and demonstrate the intraoperative use of a fully automatic method for estimation of 3-D blood flow direction from freehand 2-D Doppler ultrasound. A 3-D vessel model is reconstructed from 2-D Doppler ultrasound and used to determine the vessel architecture. The blood flow direction is then estimated automatically using the model in combination with Doppler velocity data. To enable testing and validation during surgery, the method was implemented as part of the open-source navigation system CustusX ( www.custusx.org ). Ten patients were included prospectively. Data from four patients were processed postoperatively, and data from six patients were processed intraoperatively. In total, the blood flow direction was estimated for 48 different blood vessels with a success rate of 98%. In this work, we have shown that the proposed method is suitable for fully automatic estimation of the blood flow direction in intracranial vessels during neurosurgical interventions. The method has the potential to make the understanding of the complex vascular anatomy and flow pattern more intuitive for the surgeon. The method is compatible with intraoperative use, and results can be presented within the limited time frame where they still are of clinical interest.