• 1.

    Hopkins SR, Prisk GK. Lung perfusion measured using magnetic resonance imaging: new tools for physiological insights into the pulmonary circulation. J Magn Reson Imaging. 2010;32(6):12871301.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2.

    Dobson A, Gleed RD, Meyer RE, Stewart BJ. Changes in blood flow distribution in equine lungs induced by anaesthesia. Q J Exp Physiol. 1985;70(2):283297.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3.

    Hlastala MP, Bernard SL, Erickson HH, et al. Pulmonary blood flow distribution in standing horses is not dominated by gravity. J Appl Physiol. 1996;81(3):10511061.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4.

    Staddon GE, Weaver BMQ. Regional pulmonary perfusion in horses: a comparison between anaesthetised and conscious standing animals. Res Vet Sci. 1981;30(1):4448.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Funkquist P, Wagner PD, Hedenstierna G, Persson SG, Nyman G. Ventilation-perfusion relationships during exercise in Standardbred trotters with red cell hypervolemia. Equine Vet J. 1999;30:107113.

    • Search Google Scholar
    • Export Citation
  • 6.

    Nyman G, Björk M, Funkquist P, Persson SGB, Wagner PD. Ventilation-perfusion relationships during graded exercise in the Standardbred trotter. Equine Vet J Suppl. 1995;27(S18):6369.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7.

    Seaman J, Erickson BK, Kubo K, et al. Exercise induced ventilation/perfusion inequality in the horse. Equine Vet J. 1995;27(2):104109.

  • 8.

    Stewart JH, Young IH, Rose RJ, Costas L, Barko AM. The distribution of ventilation-perfusion ratios in the lungs of newborn foals. J Dev Physiol. 1987;9(4):309324.

    • Search Google Scholar
    • Export Citation
  • 9.

    Chon D, Beck KC, Larsen RL, Shikata H, Hoffman EA. Regional pulmonary blood flow in dogs by 4D-x-ray CT. J Appl Physiol. 2006;101(5):14511465.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10.

    Kambadakone AR, Sahani DV. Body perfusion CT: technique, clinical applications, and advances. Radiol Clin North Am. 2009;47(1):161178.

  • 11.

    Dawson P. Functional imaging in CT. Eur J Radiol. 2006;60(3):331340.

  • 12.

    Miles KA, Griffiths MR. Perfusion CT: a worthwhile enhancement? Br J Radiol. 2003;76(904):220231.

  • 13.

    Miles KA. Perfusion CT for the assessment of tumour vascularity: which protocol? Br J Radiol. 2003;76(Spec No 1):S36S42.

  • 14.

    Zhao Y, Hubbard L, Malkasian S, Abbona P, Molloi S. Dynamic pulmonary CT perfusion using first-pass analysis technique with only two volume scans: validation in a swine model. PLoS One. 2020;15(2):e0228110.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15.

    Nyman G, Funkquist B, Kvart C, et al. Atelectasis causes gas exchange impairment in the anaesthetised horse. Equine Vet J. 1990;22(5):317324.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16.

    de Boor CR. A practical guide to splines. Appl Math Sci. 1978;27:149.

  • 17.

    Beck KC. Regional trapping of microspheres in the lung compares well with regional blood flow. J Appl Physiol. 1987;63(2):883889.

  • 18.

    Marshall C, Lindgren L, Marshall BE. Effects of halothane, enflurane and isoflurane on hypoxic pulmonary vasoconstriction in rat lungs in vitro. Anesthesiology. 1984;60(4):304308.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 19.

    Sanelli PC, Nicola G, Johnson R, et al. Effect of training and experience on qualitative and quantitative CT perfusion data. Am J Neuroradiol. 2007;28(3):428432.

    • Search Google Scholar
    • Export Citation
  • 20.

    Sauter AW, Merkle A, Schulze M, et al. Intraobserver and interobserver agreement of volume perfusion CT (VPCT) measurements in patients with lung lesions. Eur J Radiol. 2012;81(10):28532859.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21.

    Bammer R. Acquisition schemes for computed tomography perfusion. In: Bammer R, ed. MR and CT Perfusion and Pharmacokinetic Imaging. LWW; 2016:114144.

    • Search Google Scholar
    • Export Citation
  • 22.

    Gattinoni L, Pesenti A, Bombino S, et al. Relationships between lung computed tomographic density, gas exchange, and PEEP in acute respiratory failure. Anesthesiology. 1988;69(6):824832.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23.

    Vieira SRR, Puybasset L, Richecoeur J, et al. A lung computed tomographic assessment of positive end-expiratory pressure–induced lung overdistension. Am J Respir Crit Care Med. 1998;158(5 pt1):15711577.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24.

    Fink C, Ley S, Risse F, et al. Effect of inspiratory and expiratory breathhold on pulmonary perfusion: assessment by pulmonary perfusion magnetic resonance imaging. Invest Radiol. 2005;40(2):7279.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25.

    Tokics L, Hedenstierna G, Strandberg A, Brismar B, Lundquist H. Lung collapse and gas exchange during general anesthesia: effects of spontaneous breathing, muscle paralysis and positive end-expiratory pressure. Anesthesiology. 1987;66(2):157167.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26.

    Hallett RL, Fleischmann D. Tools of the trade for CTA: MDCT scanners and contrast medium injection protocols. Tech Vasc Interv Radiol. 2006;9(4):134142.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27.

    Hughes PM, Bisset R. Non-ionic contrast media: a comparison of iodine delivery rates during manual injection angiography. Br J Radiol. 1991;64(761):417419.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28.

    Roth R, Akin M, Deligonul U, Kern MJ. Influence of radiographic contrast media viscosity to flow through coronary angiographic catheters. Cathet Cardiovasc Diagn. 1991;22(4):290294.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 29.

    Schwab SA, Kuefner MA, Anders K, et al. Peripheral intravenous power injection of iodinated contrast media: the impact of temperature on maximum injection pressures at difference cannula sizes. Acad Radiol. 2009;16(12):15021508.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30.

    American College of Radiology Committee on Drugs and Contrast Media. ACR Manual on Contrast Media (Version 2020). American College of Radiology. Accessed January 2021. https://www.acr.org/-/media/ACR/Files/Clinical-Resources/Contrast_Media.pdf

    • Search Google Scholar
    • Export Citation
  • 31.

    Herts BR, O’Malley CM, Wirth SL, Lieber ML, Pohlman B. Power injection of contrast media using central venous catheters: feasibility, safety and efficacy. AJR Am J Roentgenol. 2001;176(2):447453.

    • Crossref
    • Search Google Scholar
    • Export Citation

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Development of a method to measure regional perfusion of the lung in anesthetized ponies using computed tomography angiography and the maximum slope model

Adam Auckburally BVSc, PhD1, Görel Nyman DVM, PhD1, Maja K. Wiklund DVM1, Anna K. Straube DVM1, Gaetano Perchiazzi MD, PhD2, Alessandro Beda PhD3, Charles J. Ley BVSc, PhD1, and Peter F. Lord DVM, PhD1
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  • 1 Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
  • | 2 Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
  • | 3 Department of Electronic Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil

Abstract

OBJECTIVE

To develop a method based on CT angiography and the maximum slope model (MSM) to measure regional lung perfusion in anesthetized ponies.

ANIMALS

6 ponies.

PROCEDURES

Anesthetized ponies were positioned in dorsal recumbency in the CT gantry. Contrast was injected, and the lungs were imaged while ponies were breathing spontaneously and while they were mechanically ventilated. Two observers delineated regions of interest in aerated and atelectatic lung, and perfusion in those regions was calculated with the MSM. Measurements obtained with a computerized method were compared with manual measurements, and computerized measurements were compared with previously reported measurements obtained with microspheres.

RESULTS

Perfusion measurements obtained with the MSM were similar to previously reported values obtained with the microsphere method. While ponies were spontaneously breathing, mean ± SD perfusion for aerated and atelectatic lung regions were 4.0 ± 1.9 and 5.0 ± 1.2 mL/min/g of lung tissue, respectively. During mechanical ventilation, values were 4.6 ± 1.2 and 2.7 ± 0.7 mL/min/g of lung tissue at end expiration and 4.1 ± 0.5 and 2.7 ± 0.6 mL/min/g of lung tissue at peak inspiration. Intraobserver agreement was acceptable, but interobserver agreement was lower. Computerized measurements compared well with manual measurements.

CLINICAL RELEVANCE

Findings showed that CT angiography and the MSM could be used to measure regional lung perfusion in dorsally recumbent anesthetized ponies. Measurements are repeatable, suggesting that the method could be used to determine efficacy of therapeutic interventions to improve ventilation-perfusion matching and for other studies for which measurement of regional lung perfusion is necessary.

Abstract

OBJECTIVE

To develop a method based on CT angiography and the maximum slope model (MSM) to measure regional lung perfusion in anesthetized ponies.

ANIMALS

6 ponies.

PROCEDURES

Anesthetized ponies were positioned in dorsal recumbency in the CT gantry. Contrast was injected, and the lungs were imaged while ponies were breathing spontaneously and while they were mechanically ventilated. Two observers delineated regions of interest in aerated and atelectatic lung, and perfusion in those regions was calculated with the MSM. Measurements obtained with a computerized method were compared with manual measurements, and computerized measurements were compared with previously reported measurements obtained with microspheres.

RESULTS

Perfusion measurements obtained with the MSM were similar to previously reported values obtained with the microsphere method. While ponies were spontaneously breathing, mean ± SD perfusion for aerated and atelectatic lung regions were 4.0 ± 1.9 and 5.0 ± 1.2 mL/min/g of lung tissue, respectively. During mechanical ventilation, values were 4.6 ± 1.2 and 2.7 ± 0.7 mL/min/g of lung tissue at end expiration and 4.1 ± 0.5 and 2.7 ± 0.6 mL/min/g of lung tissue at peak inspiration. Intraobserver agreement was acceptable, but interobserver agreement was lower. Computerized measurements compared well with manual measurements.

CLINICAL RELEVANCE

Findings showed that CT angiography and the MSM could be used to measure regional lung perfusion in dorsally recumbent anesthetized ponies. Measurements are repeatable, suggesting that the method could be used to determine efficacy of therapeutic interventions to improve ventilation-perfusion matching and for other studies for which measurement of regional lung perfusion is necessary.

Contributor Notes

Corresponding author: Adam Auckburally (adam.auckburally@slu.se)