Technical advances paving the way for non-invasive renal perfusion MRI

10.33540/730 ◽  
2021 ◽  
Author(s):  
◽  
Isabell Katrin Bones
Keyword(s):  
Renal Perfusion ◽  
Perfusion Mri ◽  
Non Invasive ◽  
Technical Advances ◽  
The Way

Non-invasive assessment of heterogeneity of gliomas using diffusion and perfusion MRI: correlation with spatially co-registered PET

2021 ◽  
pp. 028418512110069
Author(s):  
Ying Zhang ◽  
Yu Lin ◽  
Zhen Xing ◽  
Shaobo Yao ◽  
Dairong Cao ◽  
...  
Keyword(s):  
Tissue Characterization ◽  
Cerebral Blood Volume ◽  
T Test ◽  
Perfusion Mri ◽  
Perfusion Magnetic Resonance Imaging ◽  
Diagnostic Efficiency ◽  
Who Grade ◽  
Non Invasive ◽  
Glioma Grading ◽  
Relative Minimum

Background Heterogeneity of gliomas challenges the neuronavigated biopsy and oncological therapy. Diffusion and perfusion magnetic resonance imaging (MRI) can reveal the cellular and hemodynamic heterogeneity of tumors. Integrated positron emission tomography (PET)/MRI is expected to be a non-invasive imaging approach to characterizing glioma. Purpose To evaluate the value of apparent diffusion coefficient (ADC), cerebral blood volume (CBV), and spatially co-registered maximal standard uptake value (SUVmax) for tissue characterization and glioma grading. Material and Methods Thirty-seven consecutive patients with pathologically confirmed gliomas were retrospectively investigated. The relative minimum ADC (rADCmin), relative maximal ADC (rADCmax), relative maximal rCBV (rCBVmax), the relative minimum rCBV (rCBVmin), and the corresponding relative SUVmax (rSUVmax) were measured. The paired t-test was used to compare the quantitative parameters between different regions to clarify tumor heterogeneity. Imaging parameters between WHO grade IV and grade II/III gliomas were compared by t-test. The diagnostic efficiency of multiparametric PET/MRI was analyzed by receiver operating characteristic (ROC) curve. Results The values of rSUVmax were significantly different between maximal diffusion/perfusion area and minimum diffusion/perfusion area ( P < 0.001/ P < 0.001) within tumor. The values of rADCmin ( P < 0.001), rCBVmax ( P = 0.002), and corresponding rSUVmax ( P = 0.001/ P < 0.001) could be used for grading gliomas. The areas under the ROC curves of rSUVmax defined by rADCmin and rCBVmax were 0.89 and 0.91, respectively. Conclusion Diffusion and perfusion MRI can detect glioma heterogeneity with excellent molecular imaging correlations. Regions with rCBVmax suggest tissues with the highest metabolism and malignancy for guiding glioma grading and tissue sampling.

Understanding the use of pulse oximetry in COVID-19 disease

2021 ◽  
Vol 32 (8) ◽  
pp. 312-316
Author(s):  
Paul Silverston
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Respiratory Symptoms ◽  
Disease Process ◽  
Clinical Findings ◽  
The Other ◽  
Know How ◽  
Non Invasive ◽  
Pulse Oximeters ◽  
The Way

The pandemic has led to an increase in the use of pulse oximetry to assess and manage patients with COVID-19 disease. Paul Silverston explains the principles of pulse oximetry and the factors that can affect the reliability and accuracy of readings Pulse oximetry is performed to detect and quantify the degree of hypoxia in patients with respiratory symptoms and illnesses, including patients with COVID-19 disease. Pulse oximeters are non-invasive, simple to use and inexpensive, but it is important to know how to interpret the readings in the context of the patient's symptoms and the other clinical findings. In COVID-19 disease, very small differences in the oxygen saturation reading result in significant differences in the way that the patient is managed, so it is important to be aware of the factors that can affect these readings. It is also important to appreciate that a low reading in a patient with suspected or confirmed COVID-19 disease may be the result of another disease process.

MO336RENAL CONTRAST-ENHANCED ULTRASOUND (CEUS) TO EVALUATE EARLY AND CHRONIC MODIFICATIONS OF RENAL PERFUSION AND TO PREDICT RENAL DYSFUNCTION AFTER RENAL ISCHEMIA-REPERFUSION IN MICE

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Maxime Schleef ◽  
Delphine Baetz ◽  
Christelle Leon ◽  
Bruno Pillot ◽  
Gabriel Bidaux ◽  
...  
Keyword(s):  
Renal Function ◽  
Ischemia Reperfusion ◽  
Renal Perfusion ◽  
Renal Ischemia ◽  
Renal Ultrasound ◽  
Mechanical Index ◽  
Contrast Enhanced Ultrasound ◽  
Serum Urea ◽  
Non Invasive ◽  
Contrast Enhanced

Abstract Background and Aims Renal ischemia-reperfusion can lead to acute kidney injury (AKI), increasing the risk of developing chronic kidney disease (CKD) through inflammation and vascular lesions. Serum urea or creatinine level routinely used as diagnostic indices of renal function are always delayed from the onset of the disease. Therefore, we currently lack reliable markers to early detect AKI, especially in animals. We aimed to show that non-invasive renal contrast-enhanced ultrasound (CEUS) could be a reliable tool to assess early and chronic changes of renal perfusion after renal ischemia-reperfusion. Method Male C57BL6 mice underwent 15 minutes of unilateral renal ischemia by clamping of the left renal vascular pedicle (n = 7), or a sham procedure (n = 3), under inhaled general anesthesia by Sevoflurane. A renal ultrasound was performed on the left ischemic kidney at baseline 1 week before the surgery, then, 20 minutes after reperfusion to assess early modifications of renal perfusion, and 1 month after reperfusion to follow chronic modifications. CEUS was performed in supine position by using a high-resolution ultrasonic imaging system (VEVO 3100 Fujifilm Visualsonics, Toronto, Canada) with a MX550D probe fixed in place with an iron support, ensuring the constant imaging plane throughout acquisition. First, a continuous infusion of microbubbles (VS-11913, Fujifilm Visualsonics, Toronto, Canada) was done through the tail vein, then a high mechanical index burst was given to destroy microbubbles when the contrast enhancement had reached a steady state, and finally, low mechanical-index imaging mode was used until, and 30 sec after the contrast agent concentration reached the plateau. Images were recorded and were analyzed using the “destruction-replenishment” fitting model of the Vevo LAB software (Fujifilm Visualsonics, Toronto, Canada). Renal perfusion was estimated by the total renal Blood Volume (rBV) parameter and was expressed as percentage of the baseline value for each animal. Renal function was also assessed by serum urea concentration 1 month after reperfusion, and the long axis lengths of both the kidneys were measured ex vivo after the mice were euthanized. Results Renal perfusion of the ischemic kidney measured by CEUS was significantly decreased as soon as 20 minutes of reperfusion compared to baseline (median 28,8% of baseline value; interquartiles [20,1 – 69,8%]). 1 month after reperfusion, renal perfusion recovered partially but was still significantly decreased compared to baseline (median 79,9% of baseline value; interquartiles [52,8 – 99,9%]) (Figure A). In sham operated mice, renal perfusion did not differ from baseline at 20 minutes or 1 month (p &gt; 0.05). The renal function, assessed by serum urea, was mildly but significantly impaired 1 month after ischemia-reperfusion compared with sham (median serum urea 9,8 vs. 7,6 mmol/L) (p = 0.02), and this was consistent with the observed kidney atrophy in the ischemic group when compared to the contralateral kidney (median long axis length 7,5 vs 10,8 mm) (p = 0.03). Moreover, the decrease of renal perfusion 20 minutes after reperfusion was significantly correlated with the impairment of renal perfusion 1 month after reperfusion (Pearson r = 0.836, p = 0.005) and with the serum urea level at 1 month (Pearson r = -0.710, p = 0.03) (Figure B-C). Conclusion Renal CEUS was able to detect early impairment of renal perfusion as soon as 20 minutes after 15 minutes of renal ischemia in mice, and perfusion was still decreased 1 month after reperfusion, compared to baseline. This early impairment of perfusion was correlated with the chronic decrease of renal perfusion and renal function 1 month after reperfusion. This was also associated with a significant kidney atrophy. CEUS is an interesting non-invasive tool to assess renal lesions dynamically after ischemia-reperfusion.

Technical advances and pitfalls on the way to human cloning

2002 ◽  
Vol 70 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Richard Mollard ◽  
Mark Denham ◽  
Alan Trounson
Keyword(s):  
Human Cloning ◽  
Technical Advances ◽  
The Way

Influence of ageing on quantitative contrast-enhanced ultrasound of the kidneys in healthy cats

2018 ◽  
Vol 182 (18) ◽  
pp. 515-515 ◽  
Author(s):  
Emmelie Stock ◽  
Dominique Paepe ◽  
Sylvie Daminet ◽  
Luc Duchateau ◽  
Jimmy H Saunders ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Area Under The Curve ◽  
Renal Perfusion ◽  
Urine Specific Gravity ◽  
Contrast Enhanced Ultrasound ◽  
Non Invasive ◽  
Peak Enhancement ◽  
Contrast Enhanced ◽  
Lower Blood ◽  
Invasive Evaluation

The degenerative effects of ageing on the kidneys have been extensively studied in humans. However, only recently interest has been focused on renal ageing in veterinary medicine. Contrast-enhanced ultrasound allows non-invasive evaluation of renal perfusion in conscious cats. Renal perfusion parameters were obtained in 43 healthy cats aged 1–16 years old, and the cats were divided in four age categories: 1–3 years, 3–6 years, 6–10 years and over 10 years. Routine renal parameters as serum creatinine, serum urea, urine-specific gravity, urinary protein:creatinine ratio and systolic blood pressure were also measured. No significant differences in any of the perfusion parameters were observed among the different age categories. A trend towards a lower peak enhancement and wash-in area under the curve with increasing age, suggestive for a lower blood volume, was detected when comparing the cats over 10 years old with the cats of 1–3 years old. Additionally, no significant age-effect was observed for the serum and urine parameters, whereas a higher blood pressure was observed in healthy cats over 10 years old.

Effect of non-invasive remote ischemic preconditioning on intra-renal perfusion in volunteers

2016 ◽  
Vol 30 (3) ◽  
pp. 393-395 ◽  
Author(s):  
René Robert ◽  
Mathieu Vinet ◽  
Angéline Jamet ◽  
Rémi Coudroy
Keyword(s):  
Ischemic Preconditioning ◽  
Renal Perfusion ◽  
Remote Ischemic Preconditioning ◽  
Non Invasive

Retrospective respiratory triggering renal perfusion MRI

2010 ◽  
Vol 51 (10) ◽  
pp. 1163-1171 ◽  
Author(s):  
Ulrike I. Attenberger ◽  
Steven P. Sourbron ◽  
Henrik J. Michaely ◽  
Maximilian F. Reiser ◽  
Stefan O. Schoenberg
Keyword(s):  
Renal Perfusion ◽  
Perfusion Mri ◽  
Respiratory Triggering

Nierenarterienstenose: Möglichkeiten der Kernspintomographie

1989 ◽  
Vol 28 (06) ◽  
pp. 226-233 ◽  
Author(s):  
G. P. Krestin ◽  
P. Theissen ◽  
G. Friedmann ◽  
H. Schicha ◽  
A. Linden
Keyword(s):  
Renal Artery ◽  
Renal Artery Stenosis ◽  
Vascular Diseases ◽  
Renal Perfusion ◽  
Renal Arteries ◽  
Artery Stenosis ◽  
Gradient Echo ◽  
Gadolinium Dtpa ◽  
Non Invasive ◽  
Dynamic Studies

Non-invasive detection of stenotic lesions of the renal arteries remains an important clinical problem. Recent advances in magnetic resonance angiography represent a significant progress towards achieving non-invasive diagnosis of vascular diseases. The purpose of this study was to evaluate the possibilities of assessment of renal artery stenosis with commonly available hard-and software equipment. Imaging of renal arteries was performed with a ECG-gated fast multiphase gradient echo sequence which allows production of a series of images in different heart phases. Examinations were performed in 15 healthy volunteers and in 12 patients with angiographically verified renal artery stenosis. In 10 patients additional dynamic studies with fast imaging during short breath-holding periods after administration of gadolinium-DTPA served for the assessment of renal perfusion. A superconducting system operating at 1.5 T was used to produce gradient echo sequences with small flip angles and dephasing gradients of constant amplitude. To find the optimal imaging method for depiction of the renal arteries the following parameters were systematically varied: respiratory gating, resolution, number of excitations, slice thickness, phase encoding direction, rephasing gradients, Flip angle and echo time. A good visualization of the vessels was always possible and using the best parameter combination even the narrowed lumen could be assessed in some cases. With this technique or with gadolinium-enhanced dynamic studies the perfusion of the kidneys can be demonstrated. However, quantitation of the stenosis or quantitation of renal perfusion was not possible; even the depiction of the stenotic lesion was successful only in half of the cases. Thus commonly used MR equipment is not yet able to replace more invasive methods in the diagnosis of renal artery stenosis. In order to make MR angiography a successful technique for the assessment of vascular diseases more sophisticated methods that allow a quantitation of flow or velocity across the vessel, will have to be developed.

scholarly journals Antenal hydronephrosis

2018 ◽  
Vol 97 (3) ◽  
pp. 287-294
Author(s):  
Amilcar Martins Giron
Keyword(s):  
Urinary Tract ◽  
Good Condition ◽  
Voiding Cystourethrography ◽  
Functional Evaluation ◽  
Pediatric Nephrologist ◽  
Non Invasive ◽  
Technical Advances ◽  
Genitourinary Anomalies ◽  
To Receive

Genitourinary anomalies can be detected in the antenatal period with incidence of 0.5 a 1% in gestational population; 20 a 30% of these anomalies involve the urinary tract. Hydronephrosis is the most frequent urinary tract anomaly followed by cystic anomalies. Currently, technical advances of high-resolution ultrasound identify, in a non-invasive way, the gestational anatomy. The evaluation of the urinary tract, by means of complementary examinations: precocious abdominal and pelvic ultrasound (US), laboratory analysis, functional evaluation (DTPA99 -glomerular function; DMSA99 -tubular function and MAG99 -MAG-3), voiding cystourethrography and others if necessary. Conclusion - Every pregnant woman should undergo at least one morphological ultrasound examination carried out in satisfactory conditions and by qualified professional during the prenatal follow-up to identify possible malformations of the fetus. Following a pre-established roadmap of complementary examinations, it is possible to treat the pathology safely, allowing the newborn to receive hospital discharge in good condition, with a mandatory multidisciplinary outpatient follow-up with pediatric, nephrologist and pediatric urologist’s consultations.

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