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PubMed1996

[Comparison between retrograde cerebral perfusion and selective cerebral perfusion by intraoperative electroencepharogram].

We used retrograde cerebral perfusion (RCP) to protect the brain in patients undergoing aortic arch replacement from May 1991 to July 1992. Subsequently, we have been using selective cerebral perfusion (SCP). In this study, a group of six patients undergoing RPC were compared with 5 patients undergoing SCP with regard to the intraoperative electroencepharogram (EEG) and post operative clinical course. There were no deaths in either group, but transient palsy of the right arm developed in one patient in the RCP group. The amplitude of intraoperative EEG was examined at four points: before cardiopulmonary bypass, during RCP or SCP, at 30 degrees C and at 35 degrees C during rewarming. The EEG amplitude at these four points was expressed as a ratio to the value before cardiopulmonary bypass. The ratios at these four points were 1, 0, 0.08, and 0.19 in the RCP group and 1, 0, 0.70, and 0.90 in the SCP group, respectively. In the SCP group, EEG recovered rapidly, whereas in the RCP group EEG did not recover until the completion of cardiopulmonary bypass in all but one patient. These results indicated that RCP does not provide reliable protection of the brain.

Adult↗
PubMed1996

[Abnormalitis in the distributions of ventilation-perfusion ratios and diffusing capacity-perfusion ratios in three types of chronic obstructive pulmonary disease].

To assess whether diffusion-limited gas exchange plays a significant role in hypoxemia in various types of chronic obstructive pulmonary disease(COPD), we analyzed the distribution of ventilation-perfusion (VA/Q) ratios and of diffusing capacity-perfusion (G/Q) ratios. We compared VA/Q and G/Q distribution in patients with three basic types of COPD: emphysematous changes, bronchiolar involvement, and airway hypersecretion, which were classified based on symptoms and on findings of high-resolution CT. The results were that 1) hypoxemia was not caused by diffusion-limited gas exchange with low G/Q regions in any type of COPD, that 2) hypoxemia was not caused by inhomogeneities in VA/Q distribution, that 3) emphysematous changes and bronchiolar involvement were associated with high and low VA/Q regions, respectively, and that 4) either hypersecretion itself or related airway abnormalities may cause low VA/Q regions to form.

Aged↗
PubMed2000

Spin echo entrapped perfusion image (SEEPAGE). A nonsubtraction method for direct imaging of perfusion.

Arterial spin-labeled perfusion imaging is increasingly being applied to the study of the brain and other organs. To date, perfusion information has invariably been obtained by subtraction of images with and without spin-labeling of inflowing water. Due to the relatively small amount of blood which enters tissue over a typical inflow period (1-1.5 sec), subtraction errors due to image instability or, in certain circumstances, magnetization transfer effects, can lead to very significant amounts of artifactual image intensity. These problems are avoided in the nonsubtraction method described here. Initially, spins in the imaging slice are selectively saturated, leaving other spins unaffected. A subsequent spin-echo train traps these magnetizations irrespective of flow. Finally, an imaging module generates intensity only from those spins which have entered the imaging slice during the inflow period. A slight modification of the sequence facilitates validation by detecting any contaminating signal in a control image.

Artifacts↗
PubMed1981

Functional alterations of muscle perfusion in type II muscle atrophy: demonstration by lower extremity perfusion scans.

Significant progress in the clinical assessment of peripheral vascular disease has resulted from the use of radionuclide scans to evaluate alterations of blood flow through small vessels. Two patients with Type II muscle atrophy and normal vessels on muscle biopsy were examined; abnormal lower extremity perfusion scans were obtained after the administration of 99mTc-labeled human albumin microspheres directly into the femoral arteries. These case studies illustrate the use of this technique for delineating muscle groups affected by a myopathic process. Muscle perfusion scans can be used as an aid in selecting biopsy sites and may provide a means of following the response to therapy.

Adult↗
PubMedDate not supplied

Myocardial kinetics of radiolabeled perfusion agents: basis for perfusion imaging.

The myocardial deposition of radiolabeled perfusion agents permits the noninvasive assessment of regional coronary blood flow. The design of imaging protocols and the optimal interpretation of clinical perfusion studies are based on an understanding of the kinetics of blood-tissue exchange for these compounds. Thallium 201 and the technetium 99m-labeled compounds sestamibi, teboroxime, and tetrofosmin show differing myocardial extraction and retention. This review focuses on studies that used cell culture, isolated heart, and intact animal models that form the basis of our current understanding of the myocardial kinetics of these imaging agents.

Cells, Cultured↗
PubMed1999

The relation of contractile function to myocardial perfusion. Perfusion-contraction match and mismatch.

During normoperfusion, both myocardial blood flow and contractile function are heterogeneously distributed throughout the left ventricle. Midwall segment shortening is greater at the apex than at the base of the left ventricle, and greater in the anterior than in the posterior wall. Also, transmural heterogeneity of myocardial deformation exists, with greater segment shortening and wall thickening in inner than in outer myocardial layers. Myocardial blood flow is greater in inner than in outer myocardial layers. Apart from transmural heterogeneities, there are adjacent regions with largely different resting flow in the same heart. While an increase in myocardial contractile function will lead to a metabolically mediated increase in myocardial blood, an increase in regional coronary perfusion within or above the autoregulatory range does not increase regional myocardial contractile function. During hypoperfusion induced by a proximal coronary stenosis, the reduction in subendocardial blood flow is more pronounced than that in subepicardial blood flow, and contractile function in the inner myocardial layers ceases more rapidly than in the outer myocardial layers. The reduced regional myocardial contractile function is closely matched to the reduced regional myocardial blood flow; however, such a coupling between reduced flow and function is lost when ischemia is prolonged for several hours in that function for a given flow is further reduced. Also, acute embolization of the coronary microcirculation induces a progressive loss of regional myocardial function at an unchanged regional myocardial blood flow, i.e. perfusion-contraction mismatch. During reperfusion, regional myocardial contractile function remains depressed for a prolonged period of time, depending on the severity, duration and location of the preceding ischemic episode, while regional myocardial blood flow is restored to almost normal. Recovery of contractile function in the outer myocardial layers is faster than in the inner myocardial layers.

Animals↗
PubMed2002

Serial investigation of perfusion disturbances and vasogenic oedema in hypertensive encephalopathy by diffusion and perfusion weighted imaging.

Serial MRI including diffusion and perfusion imaging was performed in a patient with hypertensive encephalopathy. At admission, the patient was disorientated and presented with seizures and cortical blindness. Perfusion imaging showed a marked reduction in blood volume and flow, with corresponding vasogenic oedema in the occipital, posterior temporal, and, to a lesser extent, frontal lobes. The clinical symptoms disappeared rapidly following treatment, whereas the disturbed circulation pattern and vasogenic oedema resolved more slowly. A complete normalisation was seen after 1 year.

Brain↗
PubMed2005

Use of atropine in patients with recent myocardial infarction during exercise myocardial perfusion study. Use of atropine during exercise myocardial perfusion SPECT.

BACKGROUND: Patients with recent myocardial infarction frequently require a myocardial perfusion study for risk stratification. However a conclusive study cannot be accomplished in many due to non-attainment of target heart rate. AIM OF THE STUDY: To evaluate the effect of pre-stress administration of atropine in exercise performance of patients with recent myocardial infarction. MATERIAL AND METHODS: Study included 43 test and 43 control patients and were matched for their age, sex, status of pretest exercise tolerance, area of infarction and for interval between infarction and stress thallium test. Atropine (0.01 mg/kg) was administered intravenously 3 min prior to treadmill stress in all the 43 test patients and no atropine was administered to control patients. RESULTS: Target heart rate was attained in 95.3% patients receiving atropine compared to in 67.4% of control patients. There was no significant difference between mean ages (p>0.33), basal BP (p>0.47), peak BP (p>0.18) of both groups. There was significant difference between the increment in exercise-induced heart rate (p<0.004), peak heart rate (p<0.001) and double product (p<0.001) attained between both groups. No significant adverse effect was noted in patients who received atropine. CONCLUSION: Pre-stress administration of atropine in patients with recent myocardial infarction is safe and results in a significantly better exercise performance, which might be useful in decreasing the number of equivocal myocardial perfusion studies.

Adult↗
PubMed1975

Myocardial perfusion imaging with 99m-Tc or 113m-In macroaggregated albumin: correlation of the perfusion image with clinical, angiographic, surgical, and histologic findings.

Scintillation camera myocardial perfusion images were performed in 77 patients with proved or suspected ischemic heart disease following the intracoronary injection of 1.5 mCi 99m-Tc or 113m-In macroaggregated albumin. Perfusion images were classified as normal (36) or abnormal (41), and the location of abnormality was noted. Thirty-seven out of 41 patients with abnormal images had prior myocardial infarction based on history (30), ECG Q-waves (27), local contraction pattern abnormality (23), or direct surgical (9) or histologic (4) inspection, either singly or in combination. Three out of five patients with pre-infarction angina had image defects-none had evidence of infarction by ECG, ventriculogram, or surgical inspection. Coronary artery stenosis correlated with image defects to the extent that myocardial infarction was associated; 28 out of 29 patients with total occlusions and other evidence of infarction had image defects, four patients with complete occlusions but without other evidence of infarction had normal images. We conclude that, excepting patients with pre-infarction angina, this technique is more sensitive and direct in the identification of myocardial scar than standard ECG, clinical evaluation, or biplane left ventriculography.

Autopsy↗
PubMed1995

Simultaneous determination of etretinate, acitretin and their metabolites in perfusate, perfusate plasma, bile or hepatic tissue with reversed-phase high-performance liquid chromatography.

Etretinate is a synthetic aromatic retinoid used in the treatment of psoriasis and other disorders affecting the skin. Acitretin is the primary active metabolite of etretinate. The in situ perfused rat liver model was used to study the first-pass hepatic metabolism of etretinate and acitretin and a reliable method of quantifying etretinate and its metabolites was needed. Previously published assays allow for the simultaneous quantitation of etretinate and acitretin in blood or plasma. This paper describes an accurate and reliable reversed-phase HPLC method for the determination of etretinate, acitretin and their metabolites in whole perfusate, plasma, bile and hepatic tissue.

Acitretin↗
PubMed1997

An automatic approach to the analysis, quantitation and review of perfusion and function from myocardial perfusion SPECT images.

UNLABELLED: We have developed a software suite that automatically selects, analyses, quantitates and displays all the key image data in a myocardial perfusion SPECT study. METHODS: The files automatically selected (upon specification of the patient name) are rest and stress projections, rest and stress short axis and gated short axis files, and all 'snapshot' files. The projection data sets are presented in cine mode for evaluation of patient motion, while the lung/heart ratio at rest and stress is calculated from regions of interest (ROIs) that are automatically derived and overlayed on the LAO 45 images. Left ventricular (LV) cavity volumes at rest and stress are calculated from the short axis data sets, and the related transient ischemic dilation (TID) ratio derived and displayed. Quantitative measurements of global (ejection fraction) and regional function parameters are performed from the gated short axis dataset. All algorithms use the C++, X-Windows and OSF-Motif standards. The overall suite executes in less than 1 minute on a SunSPARC5 with 32 Mb of RAM and no proprietary hardware. RESULTS: The software was validated on 144 patients (118 rest 201T1/post-stress 99mTc-sestamibi, 18 post-stress 99mTC-sestamibi, 8 rest 201Tl) acquired on a 90 degrees dual detector (ADAC Vertex, 91 patients) and a triple detector camera (Picker Prism 3000, 53 patients). Overall, the individual algorithms for the analysis of projection, short axis and gated short axis images were successful in 622/660 (94.2%) of the images. In 80.5% of the patients (73/91 + 43/53) all algorithms executed successfully, without significant difference in success rates for 201Tl versus 99mTc-sestamibi images. CONCLUSION: Our automated approach to myocardial perfusion SPECT analysis and review is highly successful, intrinsically reproducible, and can produce time and cost savings while improving accuracy in a clinical or teleradiology-type environment.

Algorithms↗
PubMed1998

Induced cell trauma during in vitro perfusion: a comparison between two different perfusion systems.

The purpose of this study was to compare blood cell activation during in vitro long-term perfusion using 2 parallel in vitro extracorporeal membrane oxygenation (ECMO) systems. We compared two substantially different perfusion systems, an assistance respiratoire extra corporelle (AREC) system on one hand, containing an AREC pump, silicon tubing, and a hollow-fiber oxygenator, and a centrifugal pump system, on the other hand, containing a Biomedicus centrifugal pump, PVC tubing, and a membrane oxygenator. We measured the platelet count using an automated blood cell counter. Platelet activation was evaluated using a flow cytometric technique for the platelet membrane expression of glycoproteins and ELISA for the plasma concentration of beta-thromboglobulin (beta-TG), a platelet specific protein released into the blood upon platelet activation. The neutrophil count was assayed using an automated blood cell counter and the plasma concentration of cytokines using an ELISA kit. A significant difference between the two systems was observed in terms of the platelet membrane expression of glycoprotein (GP)Ib (p=0.0001) and GPIIb/IIIa (p=0.0037), indicating a lower degree of platelet activation in the AREC system. The concentration of neutrophils was significantly lower in the centrifugal system (p=0.002) compared to the AREC system. The neutrophil membrane expression of CD11b was significantly lower (p=0.0067) in the AREC system, indicating a lower degree of neutrophil activation compared to the centrifugal pump system. A significantly lower degree of hemolysis, as expressed by plasma hemoglobin, was observed in the AREC pump system (p=0.0491). In conclusion, lower degrees of the platelet membrane expression of GPIb and GPIIb/IIIa and of the neutrophil membrane expression of CD11b were observed in the AREC system, indicating a lower degree of platelet and neutrophil activation in this system. No significant difference between the two systems as to the plasma concentration of interleukin (IL)-1beta, IL-6, or IL-8 could be recorded. Further studies are warranted to specify the role of each individual component of the two systems.

Blood Platelets↗
PubMed2004

Computed tomography perfusion of the liver: assessment of pure portal blood flow studied with CT perfusion during superior mesenteric arterial portography.

PURPOSE: To quantitatively assess the portal component of hepatic blood flow using computed tomography (CT) perfusion studies during superior mesenteric arterial portography. MATERIAL AND METHODS: Thirty-four patients with hepatocellular carcinoma and liver cirrhosis (LC) and 13 patients with liver metastasis without chronic liver disease were enrolled in this study. Ten milliliters of a non-ionic contrast medium (150 mg I) was injected at a rate of 5 ml/s via a catheter placed in the superior mesenteric artery. Single-slice cine CT images at the level of the main trunk or the right/left main trunk of the portal vein were acquired over 40 s. The deconvolution method was then used on these CT images to measure blood flow (BF), blood volume (BV), and mean transit time (MTT) in (a) liver parenchyma in patients with HCC and liver cirrhosis; (b) liver parenchyma in patients with liver metastasis without cirrhosis; (c) directly in the HCC; and (d) directly in one of the metastases. RESULTS: In 34 LC patients (a), BF, BV, and MTT in the liver parenchyma were 44.7+/-24.5 ml/min/100 g, 3.9+/-2.4 ml/100 g, and 10.9+/-5.5 s, respectively. In 13 patients without cirrhosis (b), BF, BV, and MTT in the liver parenchyma were 89.6+/-52.0 ml/min/100 g, 6.3+/-3.2 ml/100 g, and 8.7+/-3.6 sec, respectively. A significant difference in BF and BV was seen in patients with liver cirrhosis compared to those without cirrhosis. BF, BV, and MTT measured directly in HCC (c) were 6.5+/-4.5 ml/min/100 g, 0.4+/-0.4 ml/100 g, and 3.0+/-3.1 sec respectively, and BF, BV, and MTT in liver metastases (d) were 19.3+/-21.7 ml/min/100 g, 0.6+/-0.8 ml/100 g, and 1.8+/-1.6 s, respectively. CONCLUSION: CT perfusion studies during superior mesenteric arterial portography allow quantitative assessment of pure portal blood flow in the liver.

Blood Flow Velocity↗
PubMed1988

Pulmonary perfusion after rt-PA therapy for acute embolism: early improvement assessed with segmental perfusion scanning.

To determine if pulmonary perfusion was improved in acute pulmonary embolism after therapy with recombinant human tissue-type plasminogen activator (rt-PA), lung scans were obtained before and a mean of 22 hours after therapy in 19 patients. The posttherapy lung scans were compared with baseline, pretherapy scans with use of two semiquantitative methods--an anteroposterior view method, similar to that used in the Urokinase Pulmonary Embolism Trial, and a segmental method that emphasized pulmonary anatomy. There was an improvement in the defect score from 0.35 to 0.14 (P less than .01) when the anteroposterior view method was used and from 0.37 to 0.16 (P less than .01) when the segmental method was used. These encouraging results in the early posttherapy period suggest that rt-PA is especially effective in improving regional perfusion after pulmonary embolism and that a larger controlled trial of therapy with rt-PA for acute pulmonary embolism should be performed. Scoring lung scans with a segmental method is feasible and appropriate for present-day lung scan technique and should be considered in future studies.

Adult↗
PubMed1999

[Evaluation of cerebral perfusion in a patient with chronic occlusive cerebrovascular disease using MRI perfusion-weighted imaging (PI)].

Ten cases with chronic occlusive cerebrovascular disease which presented cerebral arterial occlusion without showing extended high intensity area on their brain MRI T2 weighted imaging, were evaluated by MRI Perfusion-weighted imaging (PI) and correlated SPECT (123 I-IMP). Each average of PI parameter indicated misery perfusion, and was mostly detected by time to peak and rMTT imaging.

Aged↗
PubMed1989

[Studies of the methodologic value of perfusion of human placenta by the Schneider method. III. Production of alpha hcg and beta hcg during bilateral perfusion of human cotyledon].

While continuing the series of research into various aspects of human placental tissue during bilateral perfusion of after birth cotyledon in vitro, the authors made an attempt to evaluate the production of alpha hCG and beta hCG. The research was done by modified Schneider procedure. Nine experiments were carried out in different cotyledons, in each case during 120 minutes. The authors found the content of alpha hCG in mother extracorporeal circulation (M) 105.5 +/- 76.8 ng/ml, whereas in fetal circulation (F) 2.6 +/- 1.5 ng/ml. Beta hCG was found only in mother circulation and it amounted to 0.9 +/- 0.4 ng/ml. The content of beta hCG in foetal circulation in all time intervals was 0 ng/ml. Basing on their own research the authors presume that placental tissue during bilateral perfusion in vitro preserves functional activity as to the hormone examined during 120 minutes of experiment.

Chorionic Gonadotropin↗
PubMed1997

Effects of hemodilution on splanchnic perfusion and hepatorenal function. II. Renal perfusion and hepatorenal function.

Hepatorenal perfusion and function were assxssed in 22 dogs undergoing acute normovolemic hemodilution (ANH) to a hematocrit (Hct) of 20% using 6% hydroxyethyl starch (200.000/0.5) as the diluent. Organ perfusion was determined with the radioactive microspheres method. Renal function was assessed by urinary output, creatinine clearance and fractional sodium excretion. Blood volume as well as hepatic function were derived from indocyanine green (ICG) dilution kinetics. Hepatocellular integrity was determined by serum enzymatic activity of glutamate-oxalacetate-transaminase (GOT) and glutamate-pyruvate- transaminase (GPT). ANH to Hct 20% did not change blood volume and mean aortic pressure, while heart rate was slightly elevated (p<0.05) by 5 beats per minute and cardiac output increased by 29% (p<0.05). In contrast to the liver, where arterial and portal venous blood flow increased (86% and 28%, respectively; p<0.05), total renal blood flow as well as intraorgan distribution of renal blood flow remained unchanged post-ANH. While creatinine clearance remained unchanged following ANH, urinary output and fractional urinary excretion increased (p<0.05). In response to enhanced hepatic blood flow after ANH, intravascular half-life of ICG was reduced (p<0.05) and ICG clearance increased (p<0.05). Serum enzymatic activity of GPT decreased upon ANH (p<0.05), while GOT activity remained unchanged. ANH to a Hct 20% does not impair hepatorenal function. Increased urinary output points out the necessity for proper adjustment of crystalloid infusion to maintain normal intravascular volume and avoid hypovolemia and the associated risk of tissue hypoxia.

Animals↗