Relative Perfusion Research Articles

Prediction of Skin Necrosis after Mastectomy for Breast Cancer Using Indocyanine Green Angiography Imaging.

Background:In immediate tissue expander reconstruction following total mastectomy for breast cancer, indocyanine green angiography (ICGA)–guided skin trimming is useful for the prevention of complications. However, instances of unclear ICGA contrast can occur with this method, which are difficult to judge as to whether preventive trimming is warranted. To further improve the mastectomy flap necrosis rate, more accurate objective parameters are necessary.Methods:The degree of clinical improvement was compared between 81 patients trimmed according to the surgeon’s judgment (non-ICGA group) and 100 patients with ICGA-guided trimming (ICGA group). We then retrospectively measured 3 parameters [relative perfusion (RP); time (T) to reach RPmax; and slope (S = RP/T) reflecting the rate of increase to RPmax] by using region of interest analysis software and examined their relationships with skin necrosis.Results:The rate of grade III necrosis (reaching the subcutaneous fat layer) was significantly lower in the ICGA group (4.8%) than in the non-ICGA group (17.8%; P < 0.05). The specificity of RP for the diagnosis of skin necrosis was high (98.5%; cutoff value, 34). However, the sensitivities of slope parameters were higher than RP.Conclusions:ICGA-guided trimming decreased the rate of deep skin necrosis requiring additional surgical treatment. Region of interest analysis indicated that a relatively low percentage luminescence (RP < 34) was indicative of the need for skin trimming, combined with a slow increase in the perfusion of the mastectomy skin flaps.

Dynamic perfusion CT parameters and delayed contrast washout CT in characterization of adrenal tumors: A comparative study

PurposeThe study aims to compare the accuracy of washout and perfusion CT techniques in diagnosis of adrenal tumors. Patients and methodsA prospective study included 38 patients with incidentally detected adrenal masses on conventional abdominal CT studies performed for unrelated reasons were subjected to full medical history, physical examinations, serum creatinine assessment, dynamic perfusion CT using 64 MDCT scanner with Absolute washout (APW), Relative washout (RPW) assessment and CT perfusion parameters calculation [perfusion, Peak enhancement intensity (PEI), Time to peak (TTP) & Blood volume (BV)]. Time density curves (TDCs) for all adrenal masses were done. The gold standard was either follow up or histopathological examination after fine needle biopsy or surgical resection. ResultsWashout CT differentiated between adenomas and non-adenomas using APW (≥55%) with sensitivity 73.3%, specificity 90% and accuracy 82.8%, and using RPW (≥36%) with sensitivity 53.3%, specificity 85% and accuracy 81.8%. Perfusion CT differentiated between adenomas and nonadenomas using BV (≥15ml/100g) with sensitivity 80%, specificity 75% and accuracy 77.1%. TDC curves of adenomas show slow-rise platform pattern. ConclusionPerfusion CT can distinguish between adrenal adenomas and non-adenomas using the BV, however washout CT was more accurate than perfusion CT in characterization of adrenal masses using the APW and RPW.

Dynamic Contrast-Enhanced Magnetic Resonance Enterography and Dynamic Contrast-Enhanced Ultrasonography in Crohn's Disease: An Observational Comparison Study.

Purpose e Cross-sectional imaging methods are important for objective evaluationof small intestinal inflammationinCrohn'sdisease(CD).The primary aim was to compare relative parameters of intestinal perfusion between contrast-enhanced ultrasonography (CEUS) and dynamic contrast-enhanced magnetic resonance enterography (DCE-MRE) in CD. Furthermore, we aimed at testing the repeatability of regions of interest (ROIs) for CEUS. Methods This prospective study included 25 patients: 12 females (age: 37, range: 19-66) with moderate to severe CD and a bowel wall thickness>3mm evaluated with DCE-MRE and CEUS. CEUS bolus injection was performed twice for repeatability and analyzed in VueBox®. Correlations between modalities were described with Spearman's rho, limits of agreement(LoA) and intraclass correlation coefficient(ICC). ROIrepeatability for CEUS was assessed. Results s The correlation between modalities was good and very good for bowel wall thickness (ICC=0.71, P<0.001) and length of the inflamed segment (ICC=0.89, P<0.001). Moderate-weak correlations were found for the time-intensity curve parameters: peak intensity (r=0.59, P=0.006), maximum wash-in-rate (r=0.62, P=0.004), and wash-in perfusion index (r=0.47, P=0.036). Best CEUS repeatability for peak enhancement was a mean difference of 0.73 dB (95% CI: 0.17 to 1.28, P=0.01) and 95% LoA from -3.8 to 5.3 dB. Good quality of curve fit improved LoA to -2.3 to 2.8 dB. Conclusion The relative perfusion of small intestinal CD assessed with DCE-MRE and CEUS shows only a moderate correlation. Applying strict criteria for ROIs is important and allows for good CEUS repeatability.

Computing quantitative indicators of structural renal damage in pediatric DMSA scans

ObjectivesThe proposal and implementation of a computational framework for the quantification of structural renal damage from 99mTc-dimercaptosuccinic acid (DMSA) scans.The aim of this work is to propose, implement, and validate a computational framework for the quantification of structural renal damage from DMSA scans and in an observer-independent manner. Materials and methodsFrom a set of 16 pediatric DMSA-positive scans and 16 matched controls and using both expert-guided and automatic approaches, a set of image-derived quantitative indicators was computed based on the relative size, intensity and histogram distribution of the lesion. A correlation analysis was conducted in order to investigate the association of these indicators with other clinical data of interest in this scenario, including C-reactive protein (CRP), white cell count, vesicoureteral reflux, fever, relative perfusion, and the presence of renal sequelae in a 6-month follow-up DMSA scan. ResultsA fully automatic lesion detection and segmentation system was able to successfully classify DMSA-positive from negative scans (AUC=0.92, sensitivity=81% and specificity=94%). The image-computed relative size of the lesion correlated with the presence of fever and CRP levels (p<0.05), and a measurement derived from the distribution histogram of the lesion obtained significant performance results in the detection of permanent renal damage (AUC=0.86, sensitivity=100% and specificity=75%). ConclusionsThe proposal and implementation of a computational framework for the quantification of structural renal damage from DMSA scans showed a promising potential to complement visual diagnosis and non-imaging indicators.

Correlations between intravoxel incoherent motion (IVIM) parameters and histological findings in rectal cancer: preliminary results.

Our purpose was to correlate different intravoxel incoherent motion (IVIM), histopathological and clinical parameters in rectal cancer. 17 patients with histologically proven rectal cancer investigated on a 3.T device were included into the study. DWI was performed using a multi-slice single-shot echo-planar imaging sequence with b values of 0, 50, 200, 500 and 1000 s/mm.2 A polygonal region of interest was drawn within the tumors on every b image. The following parameters were retrieved from IVIM: apparent diffusion coefficient (ADC), true diffusion (D), pseudo diffusion coefficient (D*), perfusion factor (f), and relative perfusion f·D*. In every case, cell count, nucleic areas, proliferation index KI 67, and microvessel density were estimated on histopathological specimens. Pearson's correlation coefficient was used to analyze the association between the parameters. ADC correlated well with KI 67 index and D tended to correlate with cell count and KI 67. ADC and D tended to correlate with total nucleic area. The perfusion factor f correlated well with stained vessel area, total vessel area, and vessel count. D* and fD* correlated with mean vessel diameter. Distant metastasized tumors had higher D* and fD* values. IVIM parameter reflected different clinical and histopathological features in rectal cancer.

Relationships between left ventricular asynchrony and myocardial blood flow

Objective82Rb PET protocols enable determination of left ventricular asynchrony (LVAS) at rest and stress, along with myocardial blood flow (MBF). We hypothesized that in patients with resting LVAS, MBF differs between those with stress-induced LVAS improvement and those with stress-induced LVAS deterioration. MethodsWe retrospectively analyzed 82Rb rest/regadenoson stress PET studies of 195 patients evaluated for known or suspected coronary artery disease. MBF was computed from first-pass data; function and relative perfusion were computed from myocardial equilibrium data. LVAS was defined as phase contraction bandwidth (BW) above 82Rb gender-specific normal limits, with changes defined as BW moving into or out of normal ranges. ResultsAmong the 195 patients, 64 had LVAS at rest, of whom 13 reverted to normal and 51 continued to have LVAS with stress. Patients who did not improve had lower stress MBF (1.04 ± 0.69 vs 1.58 ± 0.67, p = .02) and coronary flow reserve (1.94 ± 1.16 vs 3.04 ± 1.22, p = .01) than those who did improve. ROC analysis indicated that the parameter most strongly associated with improvement in asynchrony for patients with resting LVAS was reduction in MBF heterogeneity (ROC area (accuracy) = 84%, sensitivity = 92%, and specificity = 67%). ConclusionLVAS is highly correlated with MBF and CVR, with stress-induced improvement in synchronicity most strongly associated with improved MBF homogeneity.

Novel light treatment for digital ulcers in systemic sclerosis: a feasibility study

BackgroundLocally acting, well-tolerated treatments for digital ulcers in patients with systemic sclerosis are needed. We aimed to investigate the safety, feasibility, and tolerability of a novel light treatment, and to tentatively assess treatment efficacy. MethodsLight treatment with an in-house built phototherapy lamp was administered twice per week for 3 weeks, with follow-up at 4 and 8 weeks. Adverse events were documented. Data on patient opinion about the time to deliver, feasibility (“not feasible”, “indifferent”, “feasible”), and pain (visual analogue scale [VAS], 0–100) were collected. Patient and clinician assessment of severity of digital ulcers (VAS, 0–100) was documented. An independent assessor graded change in appearance of digital ulcers from photographs (−2 to +2). Laser doppler imaging (to assess perfusion) was performed before and after treatment. A linear mixed-effects model was used to assess change in digital ulcer status. This study is registered with ClinicalTrials.gov, number NCT02472743. FindingsEight patients with 14 digital ulcers were recruited. 46 light treatments were administered, with no adverse events. All patients believed that light treatment was “feasible” and “took just the right amount of time”, with a low associated mean pain VAS of 1·6 (SD 5·2). Severity of digital ulcers as judged by patients and clinicians improved during the study (mean change in VAS −7·1 and −5·2, respectively; both p≤0·001). According to independent assessment, mean change in appearance of digital ulcers per week was 0·14 (95% CI 0·0–0·3) (p=0·01). There was a significant increase in the relative (compared with baseline) mean perfusion after (compared with before) light treatment, in particular at the centre of the digital ulcer (0·32, 95% CI 0·13–0·52; p=0·0013). InterpretationLight treatment for digital ulcers in systemic sclerosis is safe, feasible, and well tolerated. There was an early tentative suggestion of treatment efficacy. Future research is warranted to develop light-based treatment as a locally acting therapy for digital ulcers in patients with systemic sclerosis. FundingArthritis Research UK.

Impact of Time-of-Flight Reconstruction on Cardiac PET Images of Obese Patients.

The benefit of time-of-flight (TOF) information in PET oncology studies is well established, demonstrating improved signal-to-noise ratio and enhanced lesion detection. In cardiac PET studies, tracer distribution and study interpretation differ substantially from oncology PET, and the benefit of TOF is less established. We investigate the impact of TOF on reconstructed myocardial distribution in Rb PET perfusion studies of obese patients, for whom TOF would have most significant impact. Cardiac Rb PET data of 13 obese patients (8 male, 5 female patients; weight, mean, 139 kg [range, 109-191 kg]; body mass index, mean, 49 kg/m [range, 36-76 kg/m]) were analyzed retrospectively. Images were reconstructed with and without TOF and with varying number of iterative updates (2-12 iterations). Convergence and clinical relevance of differences were assessed both visually and quantitatively (automated 17-segment scoring). An anthropomorphic torso phantom also was scanned in order to study how TOF affects reconstruction of a myocardial distribution. Time-of-flight imaging provided significant improvement in image quality and convergence rate compared with non-TOF imaging. Time-of-flight reconstruction typically required 2 to 4 iterations to converge versus 8 to 12 iterations for non-TOF reconstruction. Even at 12 iterations, non-TOF images occasionally had apparent differences in relative perfusion compared with TOF images that exceeded 10% and were considered likely to affect clinical interpretation. Time-of-flight reconstruction has a significant clinical impact on cardiac PET in obese patients. When interpreting cardiac studies from non-TOF-capable PET scanners, one must ensure to reconstruct images with sufficient iterations and to be aware of potential artifacts.

P273 Prediction of treatment response in Crohn's disease patients using contrast enhanced ultrasound: a pilot study

Background: Increased vascularity of the bowel wall is an early pathologic change that occurs in patients with active Crohn's disease (CD) and is used in imaging methods with intravenous contrast. We investigated whether a baseline contrast-enhanced ultrasound (CEUS) can differentiate responders from non-responders treated medically over a period of 6 to 12 months. Methods: Unselected adult CD patients from a tertiary care IBD center were recruited. Baseline demographic and clinical data was gathered and CEUS was performed at baseline in patients using a second-generation US microbubble contrast agent (Definity®) using 0.2 ml as bolus followed by drip infusion at a fixed rate. Following placement of an ROI (region of interest) over the bowel wall, perfusion analysis software modeled time-intensity curves (TIC) and relative kinetic perfusion parameters were measured. In each patient, clinical activity, treatment and therapeutic outcome were assessed at 3, 6 and 12 months after the CEUS. Treatment changes after baseline, systemic steroid dependency, ongoing clinical activity, new disease complications and need for surgery during the observation period were considered treatment failures. CEUS parameters were compared in patients with active (aCD) versus inactive CD (aCD) at baseline and in patients with favorable versus poor outcome at 3, 6 and 12 months post CEUS. Results: Twenty-one patients (9 men, median age 32 years, median disease duration 13 years; 15 aCD and 12 with previous surgery) were recruited. Baseline kinetic CEUS parameters peak systolic velocity (PSV-wash in rate) & wash in/wash out area under curve (WiWoAUC) in bolus and drip infusion differed significantly in aCD (n=15) versus iCD patients (n=6), while there was no difference in bowel wall US features including peristalsis, vascularity, layers loss, submucosa echogenicity nor in CRP levels between the two groups (Table 2). At baseline, 8 patients were started on a new treatment or were escalated and 5 of them were non-responders at 6 months. There was a trend towards higher median values in baseline CEUS kinetic parameters (PSV and WiWoAUC) in responders versus non-responders (Table 2). Conclusions: CEUS is a potentially useful, non-invasive tool to identify patients with active CD and who are more likely to respond to therapy.

Quantification of tumor perfusion using dynamic contrast-enhanced ultrasound: impact of mathematical modeling

Dynamic contrast-enhanced ultrasound has been proposed to monitor tumor therapy, as a complement to volume measurements. To assess the variability of perfusion parameters in ideal conditions, four consecutive test–retest studies were acquired in a mouse tumor model, using controlled injections. The impact of mathematical modeling on parameter variability was then investigated. Coefficients of variation (CV) of tissue blood volume (BV) and tissue blood flow (BF) based-parameters were estimated inside 32 sub-regions of the tumors, comparing the log-normal (LN) model with a one-compartment model fed by an arterial input function (AIF) and improved by the introduction of a time delay parameter. Relative perfusion parameters were also estimated by normalization of the LN parameters and normalization of the one-compartment parameters estimated with the AIF, using a reference tissue (RT) region. A direct estimation (rRTd) of relative parameters, based on the one-compartment model without using the AIF, was also obtained by using the kinetics inside the RT region. Results of test–retest studies show that absolute regional parameters have high CV, whatever the approach, with median values of about 30% for BV, and 40% for BF. The positive impact of normalization was established, showing a coherent estimation of relative parameters, with reduced CV (about 20% for BV and 30% for BF using the rRTd approach). These values were significantly lower (p < 0.05) than the CV of absolute parameters. The rRTd approach provided the smallest CV and should be preferred for estimating relative perfusion parameters.

FUNCTIONAL STATE OF THE MICROCIRCULATION OF THE SKIN ACCORDING TO LASER DOPPLER FLOWMETRY IN PATIENTS WITH ATRIAL FIBRILLATION WHO UNDERWENT CARDIOEMBOLIC STROKE

Aim. To evaluate the features of blood flow at the level of the microcirculatory bed of the skin (MC) in the conditions of comorbid pathology and increased coagulation potential of the blood in patients with atrial fibrillation (AF). Material and methods . The following groups were formed by random sampling: the main (group 1, n=50) group of patients with paroxysmal or persistent form of AF, after cardioembolic stroke. The comparison group (group 2, n=50) consisted of patients with paroxysmal or persistent AF without a history of stroke. The control group (group 3, n=50) – patients comparable on the basic parameters of patients from groups 1 and 2, but without AF and stroke. The plasma levels of von Willebrand factor (vWF), tissue plasminogen activator inhibitor-1 (PAI-1), antithrombin III (AT III) and plasminogen were determined. All MC parameters were studied with a single-channel laser cutaneous blood flow analyzer for the general practitioner LAKK-OP in the area of the finger pad during the period, when a patient had sinus rhythm. Results. The obtained results indicate the disorders of microcirculation processes in patients with AF after stroke, which are expressed in decrease in tissue perfusion, specific oxygen consumption (I) and relative perfusion of the microcirculation saturation (Sm). Significantly higher levels of vWF, PAI-1 and low levels of AT III were observed in patients with AF and stroke than these in the group of patients with AF. It was found that Sm in patients of the group 1 statistically significantly correlated with vWF (r=-0.61; p=0.0032), plasminogen (r=0.45; p=0.0084), PAI-1 (r=-0.43; p=0.0027) and AT III (r=0.49; p=0.0065). Conclusion. The revealed disorders of microcirculatory processes are significantly related with the disturbances of the hemostatic function of the endothelium. From the pathophysiological point of view, that is one of the negative risk factors of the development of recurrent thrombus formation.

Analysis of Critically Perfused Tissues by Laser Speckle Contrast Analysis (LASCA) Perfusion Imaging

Background: The success of tissue transplantation and long-term tissue stability after wound healing depends on sufficient tissue perfusion. Laser Doppler-supported procedures allow for an objective measurement of relative tissue perfusion. The development of Speckle-based Laser Doppler imaging now enables a real-time representation of tissue perfusion. The perfusion of tissues relevant in plastic surgery such as scars, phalangeal replantations and burn wounds were systematically analysed by Laser Speckle Contrast Analysis (LASCA) imaging. Method: Perfusion of skin, scars, replanted fingers and different burn wound degrees (IIa, IIb and III) were systematically examined by LASCA imaging. Baseline perfusion of control tissue and perfusion values of compromised tissues were quantified and compared. Results: LASCA imaging shows significant differences in baseline perfusion of skin compared to atrophic scars, hypertrophic scars and keloids. Finger replantations with subsequent replantation failure show a characteristic and significant hypoperfusion in line with the expected clinical feature. A significant difference in tissue perfusion is seen in superficial (IIa) and superficial deep (IIb) burns, which are hard to distinguish on clinical examination. Deep burns (III) are characterised by hypoperfusion, which differs significantly from grade IIa and IIb burn wound perfusion, but not from baseline skin perfusion. Furthermore, the characteristic perfusion values of different burn degrees correspond to the varying treatment strategies. Conclusion: LASCA imaging is a robust method of perfusion imaging, which combines high resolution and speed. Hypoperfusion of tissues relevant to plastic surgery such as scars, phalangeal replantations and the different burn degrees (IIa, IIb and III) can be detected by LASCA imaging with high precision. Ease of use and immediate real-time imaging make LASCA imaging a reliable tool for the evaluation of tissue perfusion after plastic surgery procedures, which may influence further treatment decisions.

Featured Article: Pharmacological postconditioning with delta opioid attenuates myocardial reperfusion injury in isolated porcine hearts.

Ischemic preconditioning has been utilized to protect the heart from ischemia prior to ischemia onset, whereas postconditioning is employed to minimize the consequences of ischemia at the onset of reperfusion. The underlying mechanisms and pathways of ischemic pre- and postconditioning continue to be investigated as therapeutic targets. We evaluated the administration of a delta opioid agonist or cariporide on various parameters associated with myocardial reperfusion injury upon reperfusion of isolated porcine hearts. The hearts were reperfused invitro with a Krebs buffer containing either: (1) 1 µM Deltorphin D (delta opioid specific agonist, n = 6); (2) 3 µM cariporide (sodium-hydrogen exchange inhibitor, n = 4); or (3) no treatment (control, n = 6). Subsequently, postischemic hemodynamic performance, arrhythmia burden, relative tissue perfusion, and development of necrosis were assessed over a 2 h reperfusion period. Postconditioning with Deltorphin D significantly improved diastolic relaxation (Tau, P < 0.05 versus controls) and decreased the incidence of ventricular arrhythmias during early reperfusion. Additionally, these treated hearts demonstrated increased tissue perfusion after 2 h ( P < 0.05 versus controls), suggesting improved microvascular function. Delta opioid agonists elicited the potential to attenuate reperfusion injury, suggesting a postconditioning effect of these agents. We hypothesize that the induced benefits of delta opioids, in part, are associated with decreased calcium influx on reperfusion, independent of sodium-hydrogen exchange inhibition. Such agents may have a potential role in minimizing reperfusion injury associated with coronary stenting, bypass surgery, myocardial infarction, cardiac transplantation, or with the utilization of heart preservation systems. Impact statement In this study, we found that postconditioning with Deltorphin D significantly improved diastolic relaxation and decreased the incidence of ventricular arrhythmias during early reperfusion. Furthermore, these treated hearts demonstrated increased tissue perfusion after 2 h, suggesting improved microvascular function. Delta opioid agonists attenuated reperfusion injury, suggestive of a postconditioning effect. Such agents may have a potential role in minimizing reperfusion injury associated with coronary stenting, bypass surgery, myocardial infarction, cardiac transplantation, or with the utilization of heart preservation systems.

Validation of MRI Determination of the Penumbra by PET Measurements in Ischemic Stroke.

The concept of the ischemic penumbra was formulated on the basis of animal experiments showing functional impairment and electrophysiologic disturbances with decreasing flow to the brain below defined values (the threshold for function) and irreversible tissue damage with blood supply further decreased (the threshold for infarction). The perfusion range between these thresholds was termed the "penumbra," and restitution of flow above the functional threshold was able to reverse the deficits without permanent damage. In further experiments, the dependency of the development of irreversible lesions on the interaction of the severity and the duration of critically reduced blood flow was established, proving that the lower the flow, the shorter the time for efficient reperfusion. As a consequence, infarction develops from the core of ischemia to the areas of less severe hypoperfusion. The translation of this experimental concept as the basis for the efficient treatment of stroke requires noninvasive methods with which regional flow and energy metabolism can be repeatedly investigated to demonstrate penumbra tissue, which can benefit from therapeutic interventions. PET allows the quantification of regional cerebral blood flow, the regional oxygen extraction fraction, and the regional metabolic rate for oxygen. With these variables, clear definitions of irreversible tissue damage and of critically hypoperfused but potentially salvageable tissue (i.e., the penumbra) in stroke patients can be achieved. However, PET is a research tool, and its complex logistics limit clinical routine applications. Perfusion-weighted or diffusion-weighted MRI is a widely applicable clinical tool, and the "mismatch" between perfusion-weighted and diffusion-weighted abnormalities serves as an indicator of the penumbra. However, comparative studies of perfusion-weighted or diffusion-weighted MRI and PET have indicated overestimation of the core of irreversible infarction as well as of the penumbra by the MRI modalities. Some of these discrepancies can be explained by the nonselective application of relative perfusion thresholds, which might be improved by more complex analytic procedures. The heterogeneity of the MRI signatures used for the definition of the mismatch are also responsible for disappointing results in the application of perfusion-weighted or diffusion-weighted MRI to the selection of patients for clinical trials. As long as validation of the mismatch selection paradigm is lacking, the use of this paradigm as a surrogate marker of outcome is limited.

Acardiac twin pregnancies part III: Model simulations.

Acardiac monochorionic twins lack cardiac function but grow by passive perfusion of the pump twin's deoxygenated arterial blood through placental arterioarterial (AA) and venovenous (VV) anastomoses and by hypoxia-mediated neovascularization. Pump twins therefore must continuously increase their cardiac output which may cause heart failure. Our aims were: to adapt our twin-twin transfusion syndrome model for acardiac twin pregnancies, to simulate pump and acardiac twin development, and to examine the model for early prognostic markers of pump twin survival. We used an infinite acardiac placental resistance, based on placental dye injection studies and simulations, suggesting the AA-Acardiac-VV series resistance determines the pump twin's excess cardiac output. Pump and acardiac development were expressed by the pump's excess cardiac output versus its normal value, represented by pump/acardiac umbilical venous diameter (UVD) ratios. UVD ratios distinguish between AA-VV anastomoses that do and do not cause hydropic pump twins. Pump twins can handle relative larger acardiac perfusion at later than earlier gestation. Both VV and acardiac resistances are significantly smaller than the AA resistance, based on respectively clinical data and acardiac blood volumetric growth. Our simulations support clinical results which show that UVD ratios aid in the prediction of pump twin risk. The AA anastomosis controls the future of both the pump and the acardiac. Correlation between acardiac size and pump twin risk is secondary to the AA size but remains clinically usable. These factors may aid in the development of methods for pump twin prognosis and the promotion of selective clinical interventions.Birth Defects Research (Part A), 2016.© 2016 Wiley Periodicals, Inc. Birth Defects Research (Part A) 106:1008-1015, 2016. © 2016 Wiley Periodicals, Inc.

Therapeutic Potential of Adipose-Derived Therapeutic Factor Concentrate for Treating Critical Limb Ischemia.

Transplantation of adipose-derived stem cells (ADSCs) is an emerging therapeutic option for addressing intractable diseases such as critical limb ischemia (CLI). Evidence suggests that therapeutic effects of ADSCs are primarily mediated through paracrine mechanisms rather than transdifferentiation. These secreted factors can be captured in conditioned medium (CM) and concentrated to prepare a therapeutic factor concentrate (TFC) composed of a cocktail of beneficial growth factors and cytokines that individually and in combination demonstrate disease-modifying effects. The ability of a TFC to promote reperfusion in a rabbit model of CLI was evaluated. A total of 27 adult female rabbits underwent surgery to induce ischemia in the left hindlimb. An additional five rabbits served as sham controls. One week after surgery, the ischemic limbs received intramuscular injections of either (1) placebo (control medium), (2) a low dose of TFC, or (3) a high dose of TFC. Limb perfusion was serially assessed with a Doppler probe. Blood samples were analyzed for growth factors and cytokines. Tissue was harvested postmortem on day 35 and assessed for capillary density by immunohistochemistry. At 1 month after treatment, tissue perfusion in ischemic limbs treated with a high dose of TFC was almost double (p < 0.05) that of the placebo group [58.8 ± 23 relative perfusion units (RPU) vs. 30.7 ± 13.6 RPU; mean ± SD]. This effect was correlated with greater capillary density in the affected tissues and with transiently higher serum levels of the angiogenic and prosurvival factors vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). The conclusions from this study are that a single bolus administration of TFC demonstrated robust effects for promoting tissue reperfusion in a rabbit model of CLI and that a possible mechanism of revascularization was promotion of angiogenesis by TFC. Results of this study demonstrate that TFC represents a potent therapeutic cocktail for patients with CLI, many of whom are at risk for amputation of the affected limb.

Computing quantitative indicators of structural renal damage in pediatric DMSA scans.

The proposal and implementation of a computational framework for the quantification of structural renal damage from 99mTc-dimercaptosuccinic acid (DMSA) scans. The aim of this work is to propose, implement, and validate a computational framework for the quantification of structural renal damage from DMSA scans and in an observer-independent manner. From a set of 16 pediatric DMSA-positive scans and 16 matched controls and using both expert-guided and automatic approaches, a set of image-derived quantitative indicators was computed based on the relative size, intensity and histogram distribution of the lesion. A correlation analysis was conducted in order to investigate the association of these indicators with other clinical data of interest in this scenario, including C-reactive protein (CRP), white cell count, vesicoureteral reflux, fever, relative perfusion, and the presence of renal sequelae in a 6-month follow-up DMSA scan. A fully automatic lesion detection and segmentation system was able to successfully classify DMSA-positive from negative scans (AUC=0.92, sensitivity=81% and specificity=94%). The image-computed relative size of the lesion correlated with the presence of fever and CRP levels (p<0.05), and a measurement derived from the distribution histogram of the lesion obtained significant performance results in the detection of permanent renal damage (AUC=0.86, sensitivity=100% and specificity=75%). The proposal and implementation of a computational framework for the quantification of structural renal damage from DMSA scans showed a promising potential to complement visual diagnosis and non-imaging indicators.

Reducing Wound Tension with Undermining or Imbrication—Do They Work?

Background:For the noncolonized wound, achieving tension-free, primary wound closure is ideal. Some surgeons advocate imbrication of deeper tissues rather than undermining, posing that imbrication preserves more dermal perfusion while still reducing tension at the wound edge. We sought to determine which technique most reliably reduced wound tension while preserving dermal wound perfusion.Methods:A total of 5 standardized, symmetrical pairs of full thickness wounds were created on Duroc swine. Wound tension was measured with a Tyrolean tensiometer before and after either method of closure, whereas a speckle contrast imager was used to assess dermal edge perfusion. Skin tension and dermal perfusion were evaluated for statistical significance via paired t tests and a multivariate analysis of variance.Results:There was a significant reduction in wound tension with undermining and imbrication relative to the raw wound tension (5 and 5.9 vs 7.1 N; P < 0.05) yet no significant difference between methods of closure (P > 0.05). There was a significant reduction in dermal perfusion between unwounded skin and the imbricated wound (222 perfusion units [PU] vs 48 PU; P < 0.05) and between the unwounded skin and the undermined wound (205 vs 63 PU; P < 0.05).Conclusions:We found no significant difference in wound tension between wound undermining or imbrication and a significant decrease in dermal perfusion after imbrication and undermining although the relative decrease in perfusion was greater with imbrication. Wound undermining reduces skin tension with greater relative dermal perfusion to the skin and should be selected over wound imbrication in standard primary wound closure.

Normal Databases for the Relative Quantification of Myocardial Perfusion.

Myocardial perfusion imaging (MPI) with SPECT is performed clinically worldwide to detect and monitor coronary artery disease (CAD). MPI allows an objective quantification of myocardial perfusion at stress and rest. This established technique relies on normal databases to compare patient scans against reference normal limits. In this review, we aim to introduce the process of MPI quantification with normal databases and describe the associated perfusion quantitative measures that are used. New equipment and new software reconstruction algorithms have been introduced which require the development of new normal limits. The appearance and regional count variations of normal MPI scan may differ between these new scanners and standard Anger cameras. Therefore, these new systems may require the determination of new normal limits to achieve optimal accuracy in relative myocardial perfusion quantification. Accurate diagnostic and prognostic results rivaling those obtained by expert readers can be obtained by this widely used technique. Throughout this review, we emphasize the importance of the different normal databases and the need for specific databases relative to distinct imaging procedures. use of appropriate normal limits allows optimal quantification of MPI by taking into account subtle image differences due to the hardware and software used, and the population studied.

Myocardial contrast echocardiography in the diagnosis of a left ventricular hemangioma

Myocardial perfusion contrast echocardiography is an imaging tool for the assessment of myocardial microcirculation. It can also be used for the evaluation of the relative perfusion of a cardiac mass. Cardiac hemangiomas are rare tumors, accounting for only 2.8% of all benign primary cardiac tumors. We report a case of a 17-year-old man with a left ventricular hemangioma detected with transthoracic echocardiography. Myocardial perfusion contrast echocardiography was used to evaluate the vascularity of the cardiac mass. Using this technique malignant and hypervascular (&lt;em&gt;e.g&lt;/em&gt;., hemangioma) tumors display persistence of contrast enhancement compared to the surrounding myocardium. The mass was successfully removed and the final report from pathology showed that the left ventricular mass was a hemangioma, a hypervascular tumor