Dynamic Sonographic Tissue Perfusion Measurement

The amount of blood passing through a tissue is a fundamental parameter since metabolism and its adaptation in disease is reflected by changes of perfusion. To evaluate the functional state of a tissue or an organ it is therefore helpful to know its perfusion intensity. Inflammation for example is highlighted by an increase of perfusion whereas chronic diseases are often accompanied by atrophy of tissue and reduction of organ perfusion. We developed and present here an overview of a simple but sensitive method to quantify tissue perfusion by means of simple color Doppler sonography. This dynamic tissue perfusion measurement (DTPM) uses color hue data to calculate the mean perfusion velocity and color pixel area to calculate the perfused part of a certain region of interest. All data are referred to full heart cycles thus reflecting all changes during a heart beat. With this approach a substantial step forward is made compared to traditional resistance index (RI) or contrast enhanced ultrasound (CEUS) sonographic techniques of blood flow evaluation. This paper describes DTPM basics and shows applications in a variety of fields

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

BACKGROUND: Cortical 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. METHODS: Ninety-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. RESULTS: A 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. CONCLUSIONS: Our 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

pO polarography, contrast enhanced color duplex sonography (CDS), [18F] fluoromisonidazole and [18F] fluorodeoxyglucose positron emission tomography: validated methods for the evaluation of therapy-relevant tumor oxygenation or only bricks in the puzzle of tumor hypoxia?

<p>Abstract</p> <p>Background</p> <p>The present study was conducted to analyze the value of ([¹⁸F] fluoromisonidazole (FMISO) and [¹⁸F]-2-fluoro-2'-deoxyglucose (FDG) PET as well as color pixel density (CPD) and tumor perfusion (TP) assessed by color duplex sonography (CDS) for determination of therapeutic relevant hypoxia. As a standard for measuring tissue oxygenation in human tumors, the invasive, computerized polarographic needle electrode system (pO₂histography) was used for comparing the different non invasive measurements.</p> <p>Methods</p> <p>Until now a total of 38 Patients with malignancies of the head and neck were examined. Tumor tissue pO₂was measured using a pO₂-histograph. The needle electrode was placed CT-controlled in the tumor without general or local anesthesia. To assess the biological and clinical relevance of oxygenation measurement, the relative frequency of pO₂readings, with values ≤ 2.5, ≤ 5.0 and ≤ 10.0 mmHg, as well as mean and median pO₂were stated. FMISO PET consisted of one static scan of the relevant region, performed 120 min after intravenous administration. FMISO tumor to muscle ratios (FMISO_T/M) and tumor to blood ratios (FMISO_T/B) were calculated. FDG PET of the lymph node metastases was performed 71 ± 17 min after intravenous administration. To visualize as many vessels as possible by CDS, a contrast enhancer (Levovist^®, Schering Corp., Germany) was administered. Color pixel density (CPD) was defined as the ratio of colored to grey pixels in a region of interest. From CDS signals two parameters were extracted: color hue – defining velocity (v) and color area – defining perfused area (A). Signal intensity as a measure of tissue perfusion (TP) was quantified as follows: TP = v_mean× A_mean.</p> <p>Results</p> <p>In order to investigate the degree of linear association, we calculated the Pearson correlation coefficient. Slight (|r| > 0.4) to moderate (|r| > 0.6) correlation was found between the parameters of pO₂polarography (pO₂readings with values ≤ 2.5, ≤ 5.0 and ≤ 10.0 mmHg, as well as median pO₂), CPD and FMISO_T/M. Only a slight correlation between TP and the fraction of pO₂values ≤ 10.0 mmHg, median and mean pO₂could be detected. After exclusion of four outliers the absolute values of the Pearson correlation coefficients increased clearly. There was no relevant association between mean or maximum FDG uptake and the different polarographic- as well as the CDS parameters.</p> <p>Conclusion</p> <p>CDS and FMISO PET represent different approaches for estimation of therapy relevant tumor hypoxia. Each of these approaches is methodologically limited, making evaluation of clinical potential in prospective studies necessary.</p

Borna disease virus (BDV) circulating immunocomplex positivity in addicted patients in the Czech Republic: a prospective cohort analysis

<p>Abstract</p> <p>Background</p> <p>Borna disease virus (BDV) is an RNA virus belonging to the family Bornaviridae. Borna disease virus is a neurotropic virus that causes changes in mood, behaviour and cognition. BDV causes persistent infection of the central nervous system. Immune changes lead to activation of infection. Alcohol and drug dependence are associated with immune impairment.</p> <p>Methods</p> <p>We examined the seropositivity of BDV circulating immunocomplexes (CIC) in patients with alcohol and drug dependence and healthy individuals (blood donors). We examined 41 addicted patients for the presence of BDV CIC in the serum by ELISA at the beginning of detoxification, and after eight weeks of abstinence. This is the first such study performed in patients with alcohol and drug dependence.</p> <p>Results</p> <p>BDV CIC positivity was detected in 36.59% of addicted patients on day 0 and in 42.86% on day 56. The control group was 37.3% positive. However, we did not detect higher BDV CIC positivity in addicted patients in comparison with blood donors (p = 0.179). The significantly higher level of BDV CIC was associated with lower levels of GGT (gamma glutamyl transferase) (p = 0.027) and approached statistical significance with the lower age of addicted patients (p = 0.064). We did not find any association between BDV CIC positivity and other anamnestic and demographic characteristics.</p> <p>Conclusions</p> <p>In our study addicted patients did not have significantly higher levels of BDV CIC than the control group. The highest levels of BDV CIC were detected in patients with lower levels of GGT and a lower age.</p> <p>Trial registration</p> <p>This study was approved by the ethical committee of the University Hospital Medical Faculty of Charles University in Pilsen, Czech Republic (registration number 303/2001).</p