Noninvasive measurement of blood flow and extraction fraction

Peters, A. M.; Gunasekera, Ranjan; Henderson, B. L.; Brown, John J.; Lavender, J. P.; Souza, Maria de Lourdes Mendes de; Ash, Judith M.; Gilday, David L.

doi:10.1097/00006231-198710000-00009

Cited by 93 publications

(67 citation statements)

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“…To our knowledge, there is no reported study dealing with such a comparison. Although some previous studies have estimated an asymmetric renal blood flow between right and left kidneys in normal healthy individuals, 21 and some others have postulated that there may be possible functional asymmetry between the 2 kidneys, 22 we found no difference between the RI values of the right remnant kidney and the left remnant kidney.…”

Section: Discussioncontrasting

confidence: 84%

Resistive Index of the Remaining Kidney in Allograft Kidney Donors

Nekouei

Ahmadnia²,

Abedi³

et al. 2012

Exp Clin Transplant

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Objectives: Kidney transplant is the last resort in patients with end-stage renal disease. In living-kidney donors undergoing nephrectomy for transplant; however, morphologic and hemodynamic changes may occur in the remaining kidney with time. If there would be such a change, then it may alter the diagnostic utility of Doppler ultrasound in evaluating diseased conditions of the solitary kidney. Using Doppler ultrasound, this study sought to determine whether there are hemodynamic changes in the remaining kidney. Materials and Methods: Forty-one patients (38 men, 3 women) for kidney donation were examined using a MyLab 50 color Doppler apparatus with a convey 3.5-to 5-MHz probe. Resistive index values of the main renal, interlobar, and interlobular arteries in the remaining kidney were assessed before, and at 7 and 90 days after nephrectomy. The size and parenchymal thickness of the remaining kidney also were measured before and after nephrectomy. Results: At day 90, a statistically significant increase (P < .001) in resistive index was seen at all levels, compared with before and 7 days after nephrectomy. No significant changes, however, could be noticed on the day 7, when compared with before the nephrectomy. Renal size and parenchymal thickness remained constant over the time studied. Conclusions: Although a statistically significant increase in resistive index values of the remaining kidney was seen 90 days after the nephrectomy, these values have remained within the normal limits of renal resistive index. So, our findings indicate that resistive index measurement is useful in assessing the diseased condition of the remaining kidney after removing the contralateral kidney.

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Section: Discussioncontrasting

confidence: 84%

Resistive Index of the Remaining Kidney in Allograft Kidney Donors

Nekouei

Ahmadnia²,

Abedi³

et al. 2012

Exp Clin Transplant

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“…SPECT and dynamic susceptibility contrast only generate qualitative comparisons between the right and left hemispheres. 125 Stable xenon-enhanced CT, perfusion CT, and arterial spin-labeling are quantitatively accurate. 126,127 Stable xenon-enhanced CT requires specialized and expensive equipment.…”

Section: Perfusion Imagingmentioning

confidence: 99%

Imaging Evidence and Recommendations for Traumatic Brain Injury: Advanced Neuro- and Neurovascular Imaging Techniques

Wintermark

Sanelli

Anzai

et al. 2014

AJNR Am J Neuroradiol

112

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SUMMARY:Neuroimaging plays a critical role in the evaluation of patients with traumatic brain injury, with NCCT as the first-line of imaging for patients with traumatic brain injury and MR imaging being recommended in specific settings. Advanced neuroimaging techniques, including MR imaging DTI, blood oxygen level-dependent fMRI, MR spectroscopy, perfusion imaging, PET/SPECT, and magnetoencephalography, are of particular interest in identifying further injury in patients with traumatic brain injury when conventional NCCT and MR imaging findings are normal, as well as for prognostication in patients with persistent symptoms. These advanced neuroimaging techniques are currently under investigation in an attempt to optimize them and substantiate their clinical relevance in individual patients. However, the data currently available confine their use to the research arena for group comparisons, and there remains insufficient evidence at the time of this writing to conclude that these advanced techniques can be used for routine clinical use at the individual patient level. TBI imaging is a rapidly evolving field, and a number of the recommendations presented will be updated in the future to reflect the advances in medical knowledge. ABBREVIATIONS:BOLD ϭ blood oxygen level-dependent; FA ϭ fractional anisotropy; MD ϭ mean diffusivity; MEG ϭ magnetoencephalography; TBI ϭ traumatic

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“…[6]) was used in this and earlier studies. PI was originally derived by Blomley et al (16), based on an accepted technique for the calculation of organ blood flow from first-pass radionuclide angiography (14). The fundamental requirement for PI to correspond to tissue perfusion is the use of an intravascular CA, leading to a one-compartment model for the description of tracer kinetics.…”

Section: Discussionmentioning

confidence: 99%

“…This is also in accordance with the original application of Eq. [6] to calculate organ blood flow from first-pass radionuclide angiography (14), which is based on a one-compartment model, also described as a monoexponential residue function. As was discussed for the PI value used here, K trans of the generalized kinetic model also does not represent pure organ blood flow.…”

Section: Discussionmentioning

confidence: 99%

Dynamic T₁ mapping predicts outcome of chemoradiation therapy in primary rectal carcinoma: Sequence implementation and data analysis

Kremser

Trieb

Rudisch

et al. 2007

Magnetic Resonance Imaging

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Purpose:To describe details about the implementation of a dynamic T 1 -mapping technique and a simple data analysis strategy that can be used to predict therapy outcome in primary rectal carcinoma and to investigate the physiologic meaning of the obtained parameter. Materials and Methods:Contrast-enhanced dynamic T 1 mapping was achieved with a snapshot fast low-angle shot (FLASH) T 1 mapping sequence implemented on a 1.5T MR scanner. This method was applied to 58 patients with primary rectal cancer before onset of chemoradiation therapy. A simple data analysis strategy based on the calculation of the maximum slope of the tissue concentration-time curve divided by the maximum of the arterial input function (AIF) was used as a measure of tumor microcirculation (PI values). Results:The snapshot FLASH (SFL) T 1 -mapping technique is accurate and sensitive enough to detect inhomogeneous uptake kinetics within tumor tissue. Classifying the patients into two groups according to therapy response showed lower mean PI values for responders as compared to nonresponders. PI was found to combine information about permeability surface area product (PS) and blood volume. Conclusions:The described method based on dynamic T 1 mapping has the potential to be a clinical tool for predicting therapy outcome of preoperative chemoradiation in patients with primary rectal carcinoma.

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Noninvasive measurement of blood flow and extraction fraction

Cited by 93 publications

References 0 publications

Resistive Index of the Remaining Kidney in Allograft Kidney Donors

Resistive Index of the Remaining Kidney in Allograft Kidney Donors

Imaging Evidence and Recommendations for Traumatic Brain Injury: Advanced Neuro- and Neurovascular Imaging Techniques

Dynamic T₁ mapping predicts outcome of chemoradiation therapy in primary rectal carcinoma: Sequence implementation and data analysis

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Noninvasive measurement of blood flow and extraction fraction

Cited by 93 publications

References 0 publications

Resistive Index of the Remaining Kidney in Allograft Kidney Donors

Resistive Index of the Remaining Kidney in Allograft Kidney Donors

Imaging Evidence and Recommendations for Traumatic Brain Injury: Advanced Neuro- and Neurovascular Imaging Techniques

Dynamic T1 mapping predicts outcome of chemoradiation therapy in primary rectal carcinoma: Sequence implementation and data analysis

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Dynamic T₁ mapping predicts outcome of chemoradiation therapy in primary rectal carcinoma: Sequence implementation and data analysis