Measurement Of Tissue Perfusion Research Articles

Correlation of histopathologic and dynamic tissue perfusion measurement findings in transplanted kidneys

BackgroundCortical perfusion of the renal transplant can be non-invasively assessed by color Doppler ultrasonography. We performed the Dynamic Tissue Perfusion Measurement (DTPM) of the transplant’s renal cortex using color Doppler ultrasonography (PixelFlux technique), and compared the results with the histopathological findings of transplant biopsies.MethodsNinety-six DTPM studies of the renal transplant’s cortex followed by transplant biopsies were performed in 78 patients. The cortical perfusion data were compared with the parameter of peritubular inflammatory cell accumulation (PTC 0 to 3) based on Banff-classification system.ResultsA significant decrease of cortical perfusion could be demonstrated as the inflammatory cells accumulation in peritubular capillaries increased. Increasing peritubulitis caused a perfusion loss from central to distal layers of 79% in PTC 0, of 85% in PTC 1, of 94% in PTC 2, and of 94% in PTC 3. Furthermore, the perfusion loss due to peritubular inflammation was more prominent in the distal cortical layer. The extent of perfusion decline with increasing peritubulitis (from PTC 0 to PTC 3) was 64% in proximal 20% cortical layer (p20), 63% in proximal 50% cortical layer (p50), increased to 76% in distal 50% cortical layer (d50), and peaked at 90% in the distal 20% cortical layer (d20). For those without peritubulitis (PTC 0), the increase in the the Interstitial Fibrosis/Tubular Atrophy (IF/TA) score was accompanied by a significantly increased cortical perfusion. A Polyomavirus infection was associated with an increased cortical perfusion.ConclusionsOur study demonstrated that the perfusion of the renal transplant is associated with certain pathological changes within the graft. DTPM showed a significant reduction of cortical perfusion in the transplant renal cortex related to peritubular capillary inflammation.

Transcutaneous Oxygen Tension as a Potential Predictor of Cardiovascular Events in Type 2 Diabetes

OBJECTIVETranscutaneous oxygen tension (TcPO2) measures tissue perfusion and is important in the management of peripheral artery disease (PAD). Ankle brachial index (ABI) is used for the diagnosis of PAD and represents a predictor of major adverse cardiovascular events (MACE), even if in diabetes its diagnostic and predictive value seems to be reduced. No study has evaluated TcPO2 as a predictor of cardiovascular events. Aim of this longitudinal study was to assess whether TcPO2 is better than ABI at predicting MACE in type 2 diabetic patients.RESEARCH DESIGN AND METHODSAmong 361 consecutive patients with apparently uncomplicated diabetes, 67 MACE occurred during a follow-up period of 45.8 ± 23.2 months.RESULTSThe percentage of both subjects with low ABI (≤0.9) and subjects with low TcPO2 (≤46 mmHg as measured by a receiver operating characteristic curve) was significantly (<0.001) greater among patients with than among those without MACEs (ABI 64.2 vs. 40.8; TcPO2 58.2 vs. 34%). The Kaplan-Meier method showed that both low ABI (Mantel log-rank test, 4.087; P = 0.043) and low TcPO2 (Mantel log-rank test, 33.748; P > 0.0001) were associated with a higher rate of MACEs. Cox regression analysis showed that low TcPO2 (hazard ratio 1.78 [95% CI 1.44–2.23]; P < 0.001) was a significant predictor of MACE, while ABI did not enter the model.CONCLUSIONSThis longitudinal study showed that TcPO2 may be a potential predictor of MACE among patients with uncomplicated type 2 diabetes and that its predictive value seems to be greater than that of ABI.

039 PREVALENCE AND EXTENT OF INFARCT AND MICROVASCULAR OBSTRUCTION FOLLOWING A RANGE OF REPERFUSION TECHNIQUES IN ST-ELEVATION MYOCARDIAL INFARCTION (STEMI): Table 1

Introduction Cardiac MRI (CMR) provides unique characterisation of myocardial injury post acute STEMI. It is the gold standard for non-invasive measurement of Infarct Size (IS) and tissue perfusion during STEMI. Microvascular obstruction (MVO) describes suboptimal tissue perfusion despite restoration of flow in the infarct-related artery (IRA). IS and MVO are independent predictors of adverse remodelling and prognosis post STEMI. MVO is generally assumed to be related primarily to reperfusion. CMR extent of IS and MVO decreases after 48 h post STEMI. There is a dearth of data on the prevalence and extent of MVO in clinical practice using different reperfusion methods, in particular in those without reperfusion. We hypothesise that the extent and presence of MVO are primarily related to the extent of ischaemic injury rather than reperfusion injury. Method 94 acute STEMI subjects were studied. 75 were prospectively recruited into a study of ventricular remodelling post STEMI. 19 subjects were routine clinical CMR examinations undertaken in non-reperfused, late-presenting patients (>12 h symptoms) to assess viability. Subjects were assessed on a Siemens Avanto 1.5T system. LV function and volumes were assessed using SSFP. Ten minutes after intravenous injection of gadolinium contrast (0.2 mmol/kg), delayed contrast-enhanced images were acquired using a segmented inversion-recovery gradient-echo sequence. IS was defined as areas of hyperenhancement with signal intensity (SI) >50% of peak SI in the infarct core (Full-Width Half-Maximum technique). MVO was defined as hypointensity within areas of infarct. Independent T Test and Mann-Whitney U Test analyses were used for normally and non-parametrically distributed data respectively. Statistical significance was taken at p Results There was no significant difference in age, sex, prevalence of angina, proportion of STEMI with left anterior descending artery IRA, TIMI score or Rentrop (degree of collateralization) score in early reperfused (PCI or Thrombolysis 2 Analysis showed a trend towards higher prevalence of MVO in non-reperfused STEMI (71.4% vs 55.2%). Late PCI patients (n=6) demonstrated a trend towards higher volumes and greater extent of IS and MVO compared with non-reperfused and rescue PCI (n=8) patients. No differences were seen between rescue PCI and non-reperfused patients. Conclusions The prevalence and extent of myocardial and microvascular injury (IS, MVO) on CMR in non-reperfused STEMI is at least as much as that occurring in those undergoing early reperfusion therapy. This is despite a significantly longer time to CMR in non-reperfused patients, which would be expected to result in a reduction in IS and MVO. MVO is not exclusive to reperfusion and may represent the degree of ischaemic injury. Median (25th–75th quartiles) where non-normally distributed. Total study group (n=94) consists of early reperfused, non-reperfused, late PCI and rescue PCI patients.

Dynamic Tissue Perfusion Measurement Reveals Microvascular Perfusion Loss in Kidneys of Children With Diabetes Mellitus Type 1 (DM1)

Brief Description of the Purpose of the StudyNowadays, microalbuminuria is the first overt sign of renal damage in diabetic patients. Earlier detection of diabetic nephropathy (DNP) is wanted to prevent sequelae as long as the functional and morphological changes are still reversible.MethodsWe measured slicewise the renal cortical perfusion in 93 children and adolescents (4 - 18 years) with DM1 without microalbuminuria and 71 healthy ones of comparable ages were included.Main ResultsWe found a significantly reduced renal cortical perfusion intensity in DM1 compared to healthy children. The proximal cortex was by 21 % the distal cortex by 50% less perfused. Moreover, in addition to the lesser overall perfusion, the decline of perfusion from the central to peripheral cortex was significantly increased by 34% in DM1. The TRI correlated significantly with age (r = 0.246, p = 0.017), duration of DM1 (r = 0.260, p = 0.012), systolic blood pressure (r = 0.237, p = 0.022) and serum-creatinine (r = 0.230, p = 0.028).Importance of the ConclusionsPixelFlux-measurements might help to detect renal microvascular damage at an very early state by means of a simple, quantitative color Doppler investigation. This could help to prevent manifest renal damage and to postpone the onset of irreversible diabetic nephropathy. Brief Description of the Purpose of the StudyNowadays, microalbuminuria is the first overt sign of renal damage in diabetic patients. Earlier detection of diabetic nephropathy (DNP) is wanted to prevent sequelae as long as the functional and morphological changes are still reversible. Nowadays, microalbuminuria is the first overt sign of renal damage in diabetic patients. Earlier detection of diabetic nephropathy (DNP) is wanted to prevent sequelae as long as the functional and morphological changes are still reversible. MethodsWe measured slicewise the renal cortical perfusion in 93 children and adolescents (4 - 18 years) with DM1 without microalbuminuria and 71 healthy ones of comparable ages were included. We measured slicewise the renal cortical perfusion in 93 children and adolescents (4 - 18 years) with DM1 without microalbuminuria and 71 healthy ones of comparable ages were included. Main ResultsWe found a significantly reduced renal cortical perfusion intensity in DM1 compared to healthy children. The proximal cortex was by 21 % the distal cortex by 50% less perfused. Moreover, in addition to the lesser overall perfusion, the decline of perfusion from the central to peripheral cortex was significantly increased by 34% in DM1. The TRI correlated significantly with age (r = 0.246, p = 0.017), duration of DM1 (r = 0.260, p = 0.012), systolic blood pressure (r = 0.237, p = 0.022) and serum-creatinine (r = 0.230, p = 0.028). We found a significantly reduced renal cortical perfusion intensity in DM1 compared to healthy children. The proximal cortex was by 21 % the distal cortex by 50% less perfused. Moreover, in addition to the lesser overall perfusion, the decline of perfusion from the central to peripheral cortex was significantly increased by 34% in DM1. The TRI correlated significantly with age (r = 0.246, p = 0.017), duration of DM1 (r = 0.260, p = 0.012), systolic blood pressure (r = 0.237, p = 0.022) and serum-creatinine (r = 0.230, p = 0.028). Importance of the ConclusionsPixelFlux-measurements might help to detect renal microvascular damage at an very early state by means of a simple, quantitative color Doppler investigation. This could help to prevent manifest renal damage and to postpone the onset of irreversible diabetic nephropathy. PixelFlux-measurements might help to detect renal microvascular damage at an very early state by means of a simple, quantitative color Doppler investigation. This could help to prevent manifest renal damage and to postpone the onset of irreversible diabetic nephropathy.

Dynamic Iterative Reconstruction for Interventional 4-D C-Arm CT Perfusion Imaging

Tissue perfusion measurement using C-arm angiography systems capable of CT-like imaging (C-arm CT) is a novel technique with potentially high benefit for catheter guided treatment of stroke in the interventional suite. However, perfusion C-arm CT (PCCT) is challenging: the slow C-arm rotation speed only allows measuring samples of contrast time attenuation curves (TACs) every 5-6 s if reconstruction algorithms for static data are used. Furthermore, the peak values of the TACs in brain tissue typically lie in a range of 5-30 HU, thus perfusion imaging is very sensitive to noise. We present a dynamic, iterative reconstruction (DIR) approach to reconstruct TACs described by a weighted sum of basis functions. To reduce noise, a regularization technique based on joint bilateral filtering (JBF) is introduced. We evaluated the algorithm with a digital dynamic brain phantom and with data from six canine stroke models. With our dynamic approach, we achieve an average Pearson correlation (PC) of the PCCT canine blood flow maps to co-registered perfusion CT maps of 0.73. This PC is just as high as the PC achieved in a recent PCCT study, which required repeated injections and acquisitions.

Fluid Resuscitation Guided by Sublingual Partial Pressure of Carbon Dioxide During Hemorrhagic Shock in a Porcine Model

To avoid aggressive fluid resuscitation during hemorrhagic shock, fluid resuscitation is best guided by a specific measurement of tissue perfusion. We investigated whether fluid resuscitation guided by sublingual PCO2 would reduce the amount of resuscitation fluid without compromising the outcomes of hemorrhagic shock. Ten male domestic pigs weighing between 34 and 37 kg were used. Forty-five percent of estimated blood volume was removed during an interval of 1 h. The animals were then randomized to receive fluid resuscitation based on either sublingual PCO2 or blood pressure (BP). In the sublingual PCO2-guided group, resuscitation was initiated when sublingual PCO2 exceeded 70 Torr and stopped when it decreased to 50 Torr. In the BP-guided group, resuscitation was initiated when mean aortic pressure decreased to 60 mmHg and stopped when it increased to 90 mmHg. First, Ringer's lactate solution (RLS) of 30 mL kg was administered; subsequently, the shed blood was transfused if sublingual PCO2 remained greater than 50 Torr in the sublingual PCO2-guided group or mean aortic pressure was less than 90 mmHg in the BP-guided group. All the animals were monitored for 4 h and observed for an additional 68 h. In the sublingual PCO2-guided group, fluid resuscitation was required in only 40% of the animals. In addition, a significantly lower volume of RLS (170 ± 239 mL, P = 0.005 vs. BP-guided group) was administered without the need for blood infusion in this group. However, in the BP-guided group, all the animals required a significantly larger volume of fluid (955 ± 381 mL), including both RLS and blood. There were no differences in postresuscitation tissue microcirculation, myocardial and neurologic function, and 72-h survival between groups. During hemorrhagic shock, fluid resuscitation guided by sublingual PCO2 significantly reduced the amount of resuscitation fluid without compromising the outcomes of hemorrhagic shock.

Relationships between hypercarbic reactivity, cerebral blood flow, and arterial circulation times in patients with moyamoya disease

To evaluate the correlation between angiographic measures of Moyamoya disease and tissue-level impairment from measurements of tissue perfusion and cerebrovascular reactivity (CVR). The relationship between perfusion-weighted arterial spin labeling (ASL) and hypercarbic blood oxygenation-level dependent (BOLD) CVR and time-to-peak (TTP) were compared with angiographically measured risk factors, including arterial circulation time (ACT) and modified Suzuki Score (mSS) in patients (n = 15) with Moyamoya disease. Hemodynamic contrasts provided information not apparent from structural or angiographic imaging. Mean z-statistics demonstrate that BOLD is significantly (P = 0.017) higher in low mSS hemispheres (z-statistic = 5.0 ± 2.5) compared with high mSS hemispheres (z-statistic = 3.7 ± 1.7), suggesting that regions with less advanced stages of Moyamoya disease have higher reactivity. After correcting for multiple comparisons, a strong trend for a direct relationship (R = 0.38; P = 0.03) between BOLD TTP and ACT was observed, and a significant inverse relationship between CBF and ACT (R = -0.47; P = 0.01) was found, demonstrating that BOLD and ASL contrasts reflect DSA measures of vascular compromise in Moyamoya disease, albeit with different sensitivity. Correlative measures between angiography and hemodynamic methods suggest that BOLD and ASL could be used for expanding the diagnostic imaging infrastructure in Moyamoya patients and potentially tracking tissue response to revascularization.

Role of adenosine as an adjunct therapy in the prevention and treatment of no-reflow phenomenon in acute myocardial infarction with ST segment elevation: review of the current data

Copyright © Polskie Towarzystwo Kardiologiczne INTRODUCTION Numerous clinical studies have indicated the beneficial effects of timely, optimal (without residual stenosis) and sustained patency of an occluded epicardial artery on infarct size reduction, left ventricular (LV) function and clinical outcomes. While these observations validate the experimental findings of time-dependent myocardial salvage, patients with large regions of ischaemia continue to exhibit significant morbidity and mortality. So it is clear that additional strategies are needed to improve outcomes. Emerging evidence suggests that maximising myocardial salvage not only involves restoring the full patency of large epicardial coronary arteries, but also maintains blood flow in microcirculation of the reperfused bed [1]. Experimental models convincingly document the concept of progressive microcirculatory failure (the ‘no-reflow phenomenon’) and no-reflow appears to be an important component of the potential deleterious effect of reperfusion — myocardial reperfusion injury. In animal models, abnormalities of tissue perfusion are associated with an increase of the infarct size, and agents that preserve microvascular flow result in a significant reduction of irreversible myocyte necrosis. Diagnostic techniques to measure tissue perfusion have validated this concept in humans and it is now clear that abnormal tissue perfusion occurs frequently in patients with acute coronary syndromes (ACS) undergoing reperfusion therapy [1–6].

Sublingual Microscopy as a Measure of Tissue Perfusion In Trauma

Sublingual Microscopy as a Measure of Tissue Perfusion In Trauma

Prevalence and extent of infarct and microvascular obstruction following a range of reperfusion techniques in ST-elevation myocardial infarction

Background Cardiac MRI (CMR) provides unique characterization of myocardial injury post acute ST-Elevation Myocardial Infarction (STEMI). It is the gold standard for non-invasive measurement of Infarct Size (IS) and tissue perfusion during STEMI. Microvascular obstruction describes suboptimal tissue perfusion despite restoration of flow in the infarct-related artery (IRA). IS and MVO are independent predictors o fa dverse remodelling and prognosis post STEMI. MVO is generally assumed to be related primarily to reperfusion. There is a paucity of data on the prevalence and extent of MVO in clinical practice using a range of different reperfusion methods, and in particular in those without reperfusion. We hypothesize that the extent and presence of MVO are primarily related to the extent of ischaemia than reperfusion per se. Methods

Performance evaluation of a C-Arm CT perfusion phantom

Brain perfusion measurement in stroke patients provides important information on the infarct area and state of involved tissue. Interventional C-Arm angiography systems can provide perfusion measurements. A CT perfusion phantom was developed for C-Arm perfusion imaging to test and evaluate this method and to aid in the design and validation of scan protocols. A phantom test device was designed based on the anatomy of the human head. Four feeding arteries divided into sixteen sub-branches that lead into a sintered board simulating brain parenchyma. Perfusion measurements were performed using two conventional clinical CT scanners as the gold standard and with a C-Arm CT system to test and compare the implementations. The phantom's input parameters, contrast medium and flow properties were varied. A cerebral perfusion deficit was simulated by occlusion of a feeding artery tube. CT perfusion maps of the sintered board brain tissue surrogate were computed and qualitatively compared for both conventional CT and C-Arm CT systems. A characteristic flow pattern of the tissue board was identifiable in both modalities. The characteristic flow pattern of the resulting perfusion maps is reproducible. The calculated flow and volume were directly related. A new CT perfusion phantom was developed and tested. This phantom is an appropriate model for CT-based tissue perfusion measurements in both conventional CT scanners and C-Arm CT scanners. The influence of input parameter changes can be visualized. Perfusion deficits after occlusion of a feeding artery are readily simulated and identified with CT.

Stem cell recruitment and angiogenesis of neuropeptide substance P coupled with self-assembling peptide nanofiber in a mouse hind limb ischemia model

For the successful treatment of ischemia, it is important to resupply sufficient blood into ischemic regions by inducing angiogenesis. Many stem cell transplantation studies have been reported to enhance angiogenesis, especially those relating to mesenchymal stem cells (MSCs); however cell transplantation has a number of limitations, such as the low rate of cell survival and donor cell shortage. In this study, we developed bioactive peptides by immobilizing substance P into self-assembling peptides, and their MSCs recruiting ability and therapeutic effects were evaluated by using ischemic hind limb models. Limb ischemia was produced in athymic mice, and 1% (wt/vol) peptides were injected into ischemic sites (n = 6 in each group: ischemia, substance P, RADA16-II, RADA16-II + substance P, and RADA16-II + RADA-SP (bioactive peptides)). The tissues were harvested for histological analysis and tissue perfusion measurement at 1, 3, 7, and 28 days after injection. We observed that bioactive peptides assembled themselves (<10 nm nanofibers) and formed 3-dimensional (3D) microenvironments within ischemic regions. In the animal study, it was observed that by applying bioactive peptides, substance P continued to be released at 28 days, and consequently, MSCs were successfully recruited into ischemic regions. Bioactive peptides could prevent fibrosis, promote neovascularization, enhance tissue perfusion, and prevent limb salvages. Our results demonstrated that bioactive peptides are one of the most powerful tools for the treatment of ischemia, through their recruitment of autologous MSCs and promotion of angiogenesis without cells transplantation.

Effect of signal intensity and camera quantization on laser speckle contrast analysis

Laser speckle contrast analysis (LASCA) is limited to being a qualitative method for the measurement of blood flow and tissue perfusion as it is sensitive to the measurement configuration. The signal intensity is one of the parameters that can affect the contrast values due to the quantization of the signals by the camera and analog-to-digital converter (ADC). In this paper we deduce the theoretical relationship between signal intensity and contrast values based on the probability density function (PDF) of the speckle pattern and simplify it to a rational function. A simple method to correct this contrast error is suggested. The experimental results demonstrate that this relationship can effectively compensate the bias in contrast values induced by the quantized signal intensity and correct for bias induced by signal intensity variations across the field of view.

Dynamic Tissue Perfusion Measurement: A New Tool for Characterizing Renal Perfusion in Renal Cell Carcinoma Patients

Introduction: Renal cell carcinoma (RCC) is characterized by intense angiogenesis with hyperexpression of proangiogenic factors. This study explored the potential of dynamic tissue perfusion measurement (DTPM) to detect differences in tissue perfusion between kidneys with RCC and corresponding healthy kidneys. Patients and Methods: 30 patients with unilateral, histologically confirmed RCC underwent DTPM by color Doppler ultrasound. Before scheduled surgery, Doppler ultrasound data were acquired from four transverse areas of the affected kidney and the contralateral healthy kidney. Doppler ultrasound data were recorded over a 10-second period and characteristic tissue perfusion parameters were determined. Results: The kidneys with RCC displayed characteristic changes in perfusion parameters. A significant increase in signal intensity and a significant decrease in flow resistance were noted. A combination of several DTPM parameters was used to distinguish correctly between kidneys bearing RCC or healthy kidneys with up to 75% accuracy. There was no association between the perfusion parameters and the pathological characteristics of the respective tumors. Conclusions: DTPM is a promising tool for the evaluation of whole-organ tissue perfusion. This study demonstrates the feasibility of performing DTPM measurements in kidneys bearing RCC lesions. In tumors that are characterized by extensive neovascularization, this method has the potential to be a valuable diagnostic tool.

Assessing paediatric scald injuries using Laser Speckle Contrast Imaging

BackgroundThe use of objective methods for assessment of burns is limited. Laser Speckle Contrast Imaging (LSCI) is a non-invasive technique for instant measurement of tissue perfusion, making it potentially valuable for early prediction of burn wound outcome. AimTo evaluate the influence of technical factors on perfusion and to measure perfusion in burns 0–14 days post-burn and compare this with the outcome of the burn wound at 14 days after burn. MethodThe effect of room light, camera distance and camera angle was studied using a suspension of polystyrene particles. LSCI measurements were performed on 45 scald burns and 32 uninjured areas 0–14 days after burn. ResultTechnical factors had no clinically relevant effect on measured perfusion. Burns that healed within 14 days had a higher perfusion during the first week post-burn than burns that healed after 14 days or underwent surgery. The difference in perfusion was largest 4–7 days after burn. ConclusionLSCI allows for robust, instant measurement of burns and can easily be applied in a clinical setting. Differences in perfusion during the first week post-burn are related to the outcome after 14 days.

Radionuclide Imaging in the Diagnosis and Management of Orthopaedic Disease

Nuclear medicine imaging is often used in the diagnosis and management of several orthopaedic conditions. Bone scintigraphy measures gamma ray emission to detect the distribution of an injected radiolabeled tracer on multiple image projections. In general, this imaging modality has relatively high sensitivity but low specificity in the diagnosis of occult fractures, bone tumors, metabolic bone disease, and infection. Positron emission tomography measures tissue metabolism and perfusion by detecting short half-life positron ray emission of an injected radiopharmaceutical tracer. Historically, positron emission tomography has been used only to monitor bone metastasis and aid in the diagnosis of osteomyelitis; however, this technology has recently been applied to other orthopaedic conditions for which current imaging modalities are insufficient.

Interventional 4-D C-Arm CT Perfusion Imaging Using Interleaved Scanning and Partial Reconstruction Interpolation

Tissue perfusion measurement during catheter-guided stroke treatment in the interventional suite is currently not possible. In this work, we present a novel approach that uses a C-arm angiography system capable of computed tomography (CT)-like imaging (C-arm CT) for this purpose. With C-arm CT one reconstructed volume can be obtained every 4-6 s which makes it challenging to measure the flow of an injected contrast bolus. We have developed an interleaved scanning (IS) protocol that uses several scan sequences to increase temporal sampling. Using a dedicated 4-D reconstruction approach based on partial reconstruction interpolation (PRI) we can optimally process our data. We evaluated our combined approach (IS-PRI) with simulations and a study in five healthy pigs. In our simulations, the cerebral blood flow values (unit: ml/100 g/min) were 60 (healthy tissue) and 20 (pathological tissue). For one scan sequence the values were estimated with standard deviations of 14.3 and 2.9, respectively. For two interleaved sequences the standard deviations decreased to 3.6 and 1.5, respectively. We used perfusion CT to validate the in vivo results. With two interleaved sequences we achieved promising correlations ranging from r=0.63 to r=0.94. The results suggest that C-arm CT tissue perfusion imaging is feasible with two interleaved scan sequences.

Non-invasive assessment of renal allograft fibrosis by dynamic sonographic tissue perfusion measurement

Chronic allograft nephropathy (CAN) characterized by interstitial fibrosis and tubular atrophy is a major cause of renal transplant failure. The diagnosis can currently only be verified by a graft biopsy. To evaluate whether non-invasive dynamic color Doppler sonographic parenchymal perfusion measurements are different in grafts with various degrees of biopsy proven renal transplant fibrosis. Forty-nine adult patients were prospectively included. Four patients were excluded. Color Doppler videos from the renal cortex were recorded. Perfusion in the renal cortex was evaluated using a software package which calculates color pixel area and flow velocity, encoded by each pixel inside a region of interest of a video sequence. The software calculates parameters that describe tissue perfusion numerically. Two of these, the perfusion intensity and tissue pulsatility index, were compared to grade of interstitial fibrosis (0-3) in biopsies. Observer agreement was evaluated in a subset of 12 patients. Of the 45 patients analyzed, 18 patients had grade 0, 18 had grade 1, seven had grade 2 and two had grade 3 fibrosis. The mean perfusion intensity of grade 0 was significantly higher than that of grade 2 and 3 fibrosis in the proximal cortical layer (1.65 m/s vs. 0.84 m/s, P = 0.008). No significant difference was found between grade 0 and grade 1 fibrosis. Perfusion intensity was correlated to estimated glomerular filtration rate (Pearson r 0.51, P = 0.001, R(2) = 0.26 and 0.46, P = 0.001, R(2) = 0.22 in the distal and proximal cortex, respectively). Inter-observer agreement of the perfusion intensity, expressed as intraclass correlation coefficient was 0.69 in the proximal part of the cortex. Intra-observer agreement was 0.85 for observer 1 and 0.82 for observer 2. Perfusion intensity assessed by dynamic color Doppler measurements is significantly reduced in allografts with grade 2 and 3 fibrosis compared to allografts without fibrosis. Further studies involving longitudinal assessment of allografts undergoing protocol biopsies would be of interest.

Restriction of Renal Cortical Tissue Perfusion in Vesico-Ureteral Reflux (VUR) in Children Detected with Dynamic Tissue Perfusion Measurement (DTPM)

Restriction of Renal Cortical Tissue Perfusion in Vesico-Ureteral Reflux (VUR) in Children Detected with Dynamic Tissue Perfusion Measurement (DTPM)

Correlation of Histology and Dynamic Tissue Perfusion Measurement (DTPM) of the Colonic Wall in Ulcerative Colitis (UC)

Purpose: At present, gold standard for pre-clinical assessment of post-surgical recurrence (PSR) in Crohn’s disease (CD) is colonoscopy. Endoscopy examination is invasive, so there is a need for noninvasive and accurate methods for the diagnosis of PSR. The aim of this study was to evaluate the diagnostic performance of bowel ultrasound (B-US) in assessing early PSR when using colonoscopy as gold standard. Material & Methods: We recruited 107 consecutive CD patients with ileocolonic resection. Recurrence was assessed by colonoscopy using the Rutgeerts’ score. B-US was executed 3-6-12 months after surgery. B-US parameters considered were bowel wall thickness (BWT) measured at the level of the anastomosis, echopattern, mesenteric hypertrophy, Power Doppler signal, enlarged mesenteric lymphnodes, and complications (stricture, fistulae, abscesses, abdominal free fluids). Results: B-US and colonoscopy detected findings compatible with PSR in 93 (86.9%) and 92 (86.0%) patients, respectively. On the ROC curve a BWT . 2.5 mm showed sensitivity, specificity, and LR + of 95.6%, 66.6% and 2.87 (AUC 0.834) in predicting endoscopic PSR. At multiple logistic regression analyses BWT of anastomosis (. 2.5 mm) was the only B-US characteristic significantly (P , 0.0001) and independently (OR 5 0.0227, 95% CI 0.0052-0.0987) associated with endoscopic degree of PSR. Conclusion: B-US shows good sensitivity and specificity for the diagnosis of PSR in CD. This noninvasive technique could replace endoscopy for the diagnosis of early PSR, especially in patients who comply poorly with the endoscopy.