1
|
Cortes DRE, Stapleton MC, Schwab KE, West D, Coulson NW, O’Donnell MG, Christodoulou AG, Powers RW, Wu YL. Modeling normal mouse uterine contraction and placental perfusion with non-invasive longitudinal dynamic contrast enhancement MRI. PLoS One 2024; 19:e0303957. [PMID: 38950083 PMCID: PMC11216620 DOI: 10.1371/journal.pone.0303957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 05/05/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities. OBJECTIVE Our goal is to create a non-invasive preclinical imaging pipeline that can longitudinally probe murine placental health in vivo. We use advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development. METHODOLOGY We implement dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) and analysis pipeline to quantify uterine contraction and placental perfusion dynamics. We use optic flow and time-frequency analysis to quantify and characterize contraction-related placental motion. Our novel imaging and analysis pipeline uses subcutaneous administration of gadolinium for steepest slope-based perfusion evaluation, enabling non-invasive longitudinal monitoring. RESULTS We demonstrate that the placenta exhibits spatially asymmetric contractile motion that develops from E14.5 to E17.5. Additionally, we see that placental perfusion, perfusion delivery rate, and substrate delivery all increase from E14.5 to E17.5, with the High Perfusion Chamber (HPC) leading the placental changes that occur from E14.5 to E17.5. DISCUSSION We advance the placental perfusion chamber paradigm with a novel, physiologically based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and remodeling throughout gestation. CONCLUSION Our pipeline enables the non-invasive, longitudinal assessment of multiple placenta functions from a single imaging session. Our pipeline serves as a key toolbox for advancing research in mouse models of placental disease and disorder.
Collapse
Affiliation(s)
- Devin Raine Everaldo Cortes
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Margaret C. Stapleton
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Kristina E. Schwab
- Rangos Research Center Animal Imaging Core, Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States of America
| | - Dalton West
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Noah W. Coulson
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | | | - Anthony G. Christodoulou
- Department of Radiological Sciences and Engineering, University of California, Los Angeles, California, United States of America
| | - Robert W. Powers
- Magee-Womens Research Institute, Pittsburgh, PA, United States of America
| | - Yijen L. Wu
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, United States of America
- Rangos Research Center Animal Imaging Core, Children’s Hospital of Pittsburgh, Pittsburgh, PA, United States of America
| |
Collapse
|
2
|
Cortes DRE, Stapleton MC, Schwab KE, West D, Coulson NW, O'Donnell MG, Powers RW, Wu YL. Modeling Normal Mouse Uterine Contraction and Placental Perfusion with Non-invasive Longitudinal Dynamic Contrast Enhancement MRI. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.577398. [PMID: 38352563 PMCID: PMC10862875 DOI: 10.1101/2024.01.31.577398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
The placenta is a transient organ critical for fetal development. Disruptions of normal placental functions can impact health throughout an individual's entire life. Although being recognized by the NIH Human Placenta Project as an important organ, the placenta remains understudied, partly because of a lack of non-invasive tools for longitudinally evaluation for key aspects of placental functionalities. Non-invasive imaging that can longitudinally probe murine placental health in vivo are critical to understanding placental development throughout pregnancy. We developed advanced imaging processing schemes to establish functional biomarkers for non-invasive longitudinal evaluation of placental development. We developed a dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) pipeline combined with advanced image process methods to model uterine contraction and placental perfusion dynamics. Our novel imaging pipeline uses subcutaneous administration of gadolinium for steepest-slope based perfusion evaluation. This enables non-invasive longitudinal monitoring. Additionally, we advance the placental perfusion chamber paradigm with a novel physiologically-based threshold model for chamber localization and demonstrate spatially varying placental chambers using multiple functional metrics that assess mouse placental development and continuing remodeling throughout gestation. Lastly, using optic flow to quantify placental motions arisen from uterine contractions in conjunction with time-frequency analysis, we demonstrated that the placenta exhibited asymmetric contractile motion.
Collapse
Affiliation(s)
- Devin Raine Everaldo Cortes
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
- Rangos Research Center Animal Imaging Core, Children's Hospital of Pittsburgh, PA
| | - Margaret C Stapleton
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA
- Rangos Research Center Animal Imaging Core, Children's Hospital of Pittsburgh, PA
| | - Kristina E Schwab
- Rangos Research Center Animal Imaging Core, Children's Hospital of Pittsburgh, PA
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA
| | - Dalton West
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA
| | - Noah W Coulson
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA
| | | | | | - Yijen L Wu
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA
- Rangos Research Center Animal Imaging Core, Children's Hospital of Pittsburgh, PA
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA
| |
Collapse
|
3
|
Martin KT, Xin Y, Gaulton TG, Victor M, Santiago RR, Kim T, Morais CCA, Kazimi AA, Connell M, Gerard SE, Herrmann J, Mueller AL, Lenart A, Shen J, Khan SS, Petrov M, Reutlinger K, Rozenberg K, Amato M, Berra L, Cereda M. Electrical Impedance Tomography Identifies Evolution of Regional Perfusion in a Porcine Model of Acute Respiratory Distress Syndrome. Anesthesiology 2023; 139:815-826. [PMID: 37566686 PMCID: PMC10840641 DOI: 10.1097/aln.0000000000004731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
BACKGROUND Bedside electrical impedance tomography could be useful to visualize evolving pulmonary perfusion distributions when acute respiratory distress syndrome worsens or in response to ventilatory and positional therapies. In experimental acute respiratory distress syndrome, this study evaluated the agreement of electrical impedance tomography and dynamic contrast-enhanced computed tomography perfusion distributions at two injury time points and in response to increased positive end-expiratory pressure (PEEP) and prone position. METHODS Eleven mechanically ventilated (VT 8 ml · kg-1) Yorkshire pigs (five male, six female) received bronchial hydrochloric acid (3.5 ml · kg-1) to invoke lung injury. Electrical impedance tomography and computed tomography perfusion images were obtained at 2 h (early injury) and 24 h (late injury) after injury in supine position with PEEP 5 and 10 cm H2O. In eight animals, electrical impedance tomography and computed tomography perfusion imaging were also conducted in the prone position. Electrical impedance tomography perfusion (QEIT) and computed tomography perfusion (QCT) values (as percentages of image total) were compared in eight vertical regions across injury stages, levels of PEEP, and body positions using mixed-effects linear regression. The primary outcome was agreement between QEIT and QCT, defined using limits of agreement and Pearson correlation coefficient. RESULTS Pao2/Fio2 decreased over the course of the experiment (healthy to early injury, -253 [95% CI, -317 to -189]; early to late injury, -88 [95% CI, -151 to -24]). The limits of agreement between QEIT and QCT were -4.66% and 4.73% for the middle 50% quantile of average regional perfusion, and the correlation coefficient was 0.88 (95% CI, 0.86 to 0.90]; P < 0.001). Electrical impedance tomography and computed tomography showed similar perfusion redistributions over injury stages and in response to increased PEEP. QEIT redistributions after positional therapy underestimated QCT in ventral regions and overestimated QCT in dorsal regions. CONCLUSIONS Electrical impedance tomography closely approximated computed tomography perfusion measures in experimental acute respiratory distress syndrome, in the supine position, over injury progression and with increased PEEP. Further validation is needed to determine the accuracy of electrical impedance tomography in measuring perfusion redistributions after positional changes. EDITOR’S PERSPECTIVE
Collapse
Affiliation(s)
- Kevin T Martin
- Department of Anesthesia and Perioperative Care, University of California San Francisco, CA, USA
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi Xin
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Timothy G Gaulton
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Marcus Victor
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Electronics Engineering Division, Aeronautics Institute of Technology, São Paulo, Brazil
| | - Roberta R Santiago
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Taehwan Kim
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Caio C A Morais
- Department of Physical Therapy, Federal University of Pernambuco, Recife, Brazil
| | - Aubrey A Kazimi
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Marc Connell
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
- University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Sarah E Gerard
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - Jacob Herrmann
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
| | - Ariel L Mueller
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Austin Lenart
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Jiacheng Shen
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Sherbano S Khan
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Mihail Petrov
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Kristan Reutlinger
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Karina Rozenberg
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Marcelo Amato
- Department of Cardio-Pulmonary, University of São Paulo, São Paulo, Brazil
| | - Lorenzo Berra
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| |
Collapse
|
4
|
Reder SR, Lückerath S, Neulen A, Beiser KU, Grauhan NF, Othman AE, Brockmann MA, Brockmann C, Kronfeld A. DSA-Based 2D Perfusion Measurements in Delayed Cerebral Ischemia to Estimate the Clinical Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage: A Technical Feasibility Study. J Clin Med 2023; 12:4135. [PMID: 37373828 DOI: 10.3390/jcm12124135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/05/2023] [Accepted: 06/17/2023] [Indexed: 06/29/2023] Open
Abstract
(1) Background: To predict clinical outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH) and delayed cerebral ischemia (DCI) by assessment of the cerebral perfusion using a 2D perfusion angiography (2DPA) time-contrast agent (CA) concentration model. (2) Methods: Digital subtraction angiography (DSA) data sets of n = 26 subjects were acquired and post-processed focusing on changes in contrast density using a time-concentration model at three time points: (i) initial presentation with SAH (T0); (ii) vasospasm-associated acute clinical impairment (T1); and (iii) directly after endovascular treatment (T2) of SAH-associated large vessel vasospasm (LVV), which resulted in n = 78 data sets. Maximum slope (MS in SI/ms), time-to-peak (TTP in ms), and maximum amplitude of a CA bolus (dSI) were measured in brain parenchyma using regions of interest (ROIs). First, acquired parameters were standardized to the arterial input function (AIF) and then statistically analyzed as mean values. Additionally, data were clustered into two subsets consisting of patients with regredient or with stable/progredient symptoms (or Doppler signals) after endovascular treatment (n = 10 vs. n = 16). (3) Results: Perfusion parameters (MS, TTP, and dSI) differed significantly between T0 and T1 (p = 0.003 each). Significant changes between T1 and T2 were only detectable for MS (0.041 ± 0.016 vs. 0.059 ± 0.026; p = 0.011) in patients with regredient symptoms at T2 (0.04 ± 0.012 vs. 0.066 ± 0.031; p = 0.004). For dSI, there were significant differences between T0 and T2 (5095.8 ± 2541.9 vs. 3012.3 ± 968.3; p = 0.001), especially for those with stable symptoms at T2 (5685.4 ± 2967.2 vs. 3102.8 ± 1033.2; p = 0.02). Multiple linear regression analysis revealed that a) the difference in MS between T1 and T2 and b) patient's age (R = 0.6; R2 = 0.34; p = 0.009) strongly predict the modified Rankin Scale (mRS) at discharge. (4) Conclusions: 2DPA allows the direct measurement of treatment effects in SAH associated DCI and may be used to predict outcomes in these critically ill patients.
Collapse
Affiliation(s)
- Sebastian R Reder
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Steffen Lückerath
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Axel Neulen
- Department of Neurosurgery, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Katja U Beiser
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Nils F Grauhan
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Ahmed E Othman
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Marc A Brockmann
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Carolin Brockmann
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| | - Andrea Kronfeld
- Department of Neuroradiology, University Medical Centre, Johannes Gutenberg University of Mainz, 55131 Mainz, Germany
| |
Collapse
|
5
|
Xin Y, Kim T, Winkler T, Brix G, Gaulton T, Gerard SE, Herrmann J, Martin KT, Victor M, Reutlinger K, Amato M, Berra L, Kalra MK, Cereda M. Improving pulmonary perfusion assessment by dynamic contrast-enhanced computed tomography in an experimental lung injury model. J Appl Physiol (1985) 2023; 134:1496-1507. [PMID: 37167261 PMCID: PMC10228674 DOI: 10.1152/japplphysiol.00159.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/24/2023] [Accepted: 05/11/2023] [Indexed: 05/13/2023] Open
Abstract
Pulmonary perfusion has been poorly characterized in acute respiratory distress syndrome (ARDS). Optimizing protocols to measure pulmonary blood flow (PBF) via dynamic contrast-enhanced (DCE) computed tomography (CT) could improve understanding of how ARDS alters pulmonary perfusion. In this study, comparative evaluations of injection protocols and tracer-kinetic analysis models were performed based on DCE-CT data measured in ventilated pigs with and without lung injury. Ten Yorkshire pigs (five with lung injury, five healthy) were anesthetized, intubated, and mechanically ventilated; lung injury was induced by bronchial hydrochloric acid instillation. Each DCE-CT scan was obtained during a 30-s end-expiratory breath-hold. Reproducibility of PBF measurements was evaluated in three pigs. In eight pigs, undiluted and diluted Isovue-370 were separately injected to evaluate the effect of contrast viscosity on estimated PBF values. PBF was estimated with the peak-enhancement and the steepest-slope approach. Total-lung PBF was estimated in two healthy pigs to compare with cardiac output measured invasively by thermodilution in the pulmonary artery. Repeated measurements in the same animals yielded a good reproducibility of computed PBF maps. Injecting diluted isovue-370 resulted in smaller contrast-time curves in the pulmonary artery (P < 0.01) and vein (P < 0.01) without substantially diminishing peak signal intensity (P = 0.46 in the pulmonary artery) compared with the pure contrast agent since its viscosity is closer to that of blood. As compared with the peak-enhancement model, PBF values estimated by the steepest-slope model with diluted contrast were much closer to the cardiac output (R2 = 0.82) as compared with the peak-enhancement model. DCE-CT using the steepest-slope model and diluted contrast agent provided reliable quantitative estimates of PBF.NEW & NOTEWORTHY Dynamic contrast-enhanced CT using a lower-viscosity contrast agent in combination with tracer-kinetic analysis by the steepest-slope model improves pulmonary blood flow measurements and assessment of regional distributions of lung perfusion.
Collapse
Affiliation(s)
- Yi Xin
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts, United States
| | - Taehwan Kim
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
| | - Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts, United States
| | - Gunnar Brix
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Salzgitter, Germany
| | - Timothy Gaulton
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts, United States
| | - Sarah E Gerard
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States
| | - Jacob Herrmann
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, United States
| | - Kevin T Martin
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
| | - Marcus Victor
- Disciplina de Pneumologia, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
- Electronics Engineering Division, Aeronautics Institute of Technology, Sao Paulo, Brazil
| | - Kristan Reutlinger
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Marcelo Amato
- Disciplina de Pneumologia, Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Lorenzo Berra
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts, United States
| | - Mannudeep K Kalra
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, United States
| | - Maurizio Cereda
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts, United States
| |
Collapse
|
6
|
Vignon-Clementel IE, Jagiella N, Dichamp J, Kowalski J, Lederle W, Laue H, Kiessling F, Sedlaczek O, Drasdo D. A proof-of-concept pipeline to guide evaluation of tumor tissue perfusion by dynamic contrast-agent imaging: Direct simulation and inverse tracer-kinetic procedures. FRONTIERS IN BIOINFORMATICS 2023; 3:977228. [PMID: 37122998 PMCID: PMC10135870 DOI: 10.3389/fbinf.2023.977228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 02/07/2023] [Indexed: 05/02/2023] Open
Abstract
Dynamic contrast-enhanced (DCE) perfusion imaging has shown great potential to non-invasively assess cancer development and its treatment by their characteristic tissue signatures. Different tracer kinetics models are being applied to estimate tissue and tumor perfusion parameters from DCE perfusion imaging. The goal of this work is to provide an in silico model-based pipeline to evaluate how these DCE imaging parameters may relate to the true tissue parameters. As histology data provides detailed microstructural but not functional parameters, this work can also help to better interpret such data. To this aim in silico vasculatures are constructed and the spread of contrast agent in the tissue is simulated. As a proof of principle we show the evaluation procedure of two tracer kinetic models from in silico contrast-agent perfusion data after a bolus injection. Representative microvascular arterial and venous trees are constructed in silico. Blood flow is computed in the different vessels. Contrast-agent input in the feeding artery, intra-vascular transport, intra-extravascular exchange and diffusion within the interstitial space are modeled. From this spatiotemporal model, intensity maps are computed leading to in silico dynamic perfusion images. Various tumor vascularizations (architecture and function) are studied and show spatiotemporal contrast imaging dynamics characteristic of in vivo tumor morphotypes. The Brix II also called 2CXM, and extended Tofts tracer-kinetics models common in DCE imaging are then applied to recover perfusion parameters that are compared with the ground truth parameters of the in silico spatiotemporal models. The results show that tumor features can be well identified for a certain permeability range. The simulation results in this work indicate that taking into account space explicitly to estimate perfusion parameters may lead to significant improvements in the perfusion interpretation of the current tracer-kinetics models.
Collapse
Affiliation(s)
| | | | | | | | - Wiltrud Lederle
- Institute for Experimental Molecular Imaging (ExMI), University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Hendrik Laue
- Fraunhofer MEVIS, Institute for Digital Medicine, Bremen, Germany
| | - Fabian Kiessling
- Institute for Experimental Molecular Imaging (ExMI), University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
- Fraunhofer MEVIS, Institute for Digital Medicine, Aachen, Germany
| | - Oliver Sedlaczek
- Department of NCT Radiology Uniklinikum/DKFZ Heidelberg, Heidelberg, Germany
| | - Dirk Drasdo
- Inria, Palaiseau, France
- IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
- *Correspondence: Irene E. Vignon-Clementel, ; Dirk Drasdo,
| |
Collapse
|
7
|
Cressoni M, Cozzi A, Schiaffino S, Cadringher P, Vitali P, Basso G, Ippolito D, Sardanelli F. Computation of contrast-enhanced perfusion using only two CT scan phases: a proof-of-concept study on abdominal organs. Eur Radiol Exp 2022; 6:37. [PMID: 36031643 PMCID: PMC9420683 DOI: 10.1186/s41747-022-00292-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/14/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Computed tomography perfusion imaging (CTPI) by repeated scanning has clinical relevance but implies relatively high radiation exposure. We present a method to measure perfusion from two CT scan phases only, considering tissue enhancement, feeding vessel (aortic) peak enhancement, and bolus shape.
Methods
CTPI scans (each with 40 frames acquired every 1.5 s) of 11 patients with advanced hepatocellular carcinoma (HCC) enrolled between 2012 and 2016 were retrospectively analysed (aged 69 ± 9 years, 8/11 males). Perfusion was defined as the maximal slope of the time-enhancement curve divided by the peak enhancement of the feeding vessel (aorta). Perfusion was computed two times, first using the maximum slope derived from all data points and then using the peak tissue enhancement and the bolus shape obtained from the aortic curve.
Results
Perfusion values from the two methods were linearly related (r2 = 0.92, p < 0.001; Bland–Altman analysis bias -0.12). The mathematical model showed that the perfusion ratio of two ROIs with the same feeding vessel (aorta) corresponds to their peak enhancement ratio (r2 = 0.55, p < 0.001; Bland–Altman analysis bias -0.68). The relationship between perfusion and tissue enhancement is predicted to be linear in the clinical range of interest, being only function of perfusion, peak feeding vessel enhancement, and bolus shape.
Conclusions
This proof-of-concept study showed that perfusion values of HCC, kidney, and pancreas could be computed using enhancement measured only with two CT scan phases, if aortic peak enhancement and bolus shape are known.
Collapse
|
8
|
Fuentes D, Thompson E, Jacobsen M, Crouch AC, Layman RR, Riviere B, Cressman E. Imaging-based characterization of convective tissue properties. Int J Hyperthermia 2021; 37:155-163. [PMID: 33426993 PMCID: PMC7983068 DOI: 10.1080/02656736.2020.1845403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Convective transport is an important phenomenon for nanomedicine delivery. We present an imaging-based approach to recover tissue properties that are significant in the accumulation of nanoparticles delivered via systemic methods. The classical pharmacokinetic analysis develops governing equations for the particle transport from a first principle mass balance. Fundamentally, the governing equations for compartmental mass balance represent a spatially invariant mass transport between compartments and do not capture spatially variant convection phenomena. Further, the parameters recovered from this approach do not necessarily have direct meaning with respect to the governing equations for convective transport. In our approach, a framework is presented for directly measuring permeability in the sense of Darcy flow through porous tissue. Measurements from our approach are compared to an extended Tofts model as a control. We demonstrate that a pixel-wise iterative clustering algorithm may be applied to reduce the parameter space of the measurements. We show that measurements obtained from our approach are correlated with measurements obtained from the extended Tofts model control. These correlations demonstrate that the proposed approach contains similar information to an established compartmental model and may be useful in providing an alternative theoretical framework for parameterizing mathematical models for treatment planning and diagnostic studies involving nanomedicine where convection dominated effects are important.
Collapse
Affiliation(s)
- D Fuentes
- Departments of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.,Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA
| | - E Thompson
- Departments of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - M Jacobsen
- Departments of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - A Colleen Crouch
- Interventional Radiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - R R Layman
- Departments of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - B Riviere
- Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA
| | - E Cressman
- Interventional Radiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| |
Collapse
|
9
|
Bao Q, Hadas R, Markovic S, Neeman M, Frydman L. Diffusion and perfusion MRI of normal, preeclamptic and growth-restricted mice models reveal clear fetoplacental differences. Sci Rep 2020; 10:16380. [PMID: 33009455 PMCID: PMC7532452 DOI: 10.1038/s41598-020-72885-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/28/2020] [Indexed: 12/13/2022] Open
Abstract
Diffusion-weighted MRI on rodents could be valuable to evaluate pregnancy-related dysfunctions, particularly in knockout models whose biological nature is well understood. Echo Planar Imaging’s sensitivity to motions and to air/water/fat heterogeneities, complicates these studies in the challenging environs of mice abdomens. Recently developed MRI methodologies based on SPatiotemporal ENcoding (SPEN) can overcome these obstacles, and deliver diffusivity maps at ≈150 µm in-plane resolutions. The present study exploits these capabilities to compare the development in wildtype vs vascularly-altered mice. Attention focused on the various placental layers—deciduae, labyrinth, trophoblast, fetal vessels—that the diffusivity maps could resolve. Notable differences were then observed between the placental developments of wildtype vs diseased mice; these differences remained throughout the pregnancies, and were echoed by perfusion studies relying on gadolinium-based dynamic contrast-enhanced MRI. Longitudinal monitoring of diffusivity in the animals throughout the pregnancies also showed differences between the development of the fetal brains in the wildtype and vascularly-altered mice, even if these disparities became progressively smaller as the pregnancies progressed. These results are analyzed on the basis of the known physiology of normal and preeclamptic pregnancies, as well as in terms of the potential that they might open for the early detection of disorders in human pregnancies.
Collapse
Affiliation(s)
- Qingjia Bao
- Department of Chemical and Biological Physics, Weizmann Institute, 7610001, Rehovot, Israel
| | - Ron Hadas
- Department of Biological Regulation, Weizmann Institute, 7610001, Rehovot, Israel
| | - Stefan Markovic
- Department of Chemical and Biological Physics, Weizmann Institute, 7610001, Rehovot, Israel
| | - Michal Neeman
- Department of Biological Regulation, Weizmann Institute, 7610001, Rehovot, Israel
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute, 7610001, Rehovot, Israel.
| |
Collapse
|
10
|
Lee SH, Rimner A, Deasy JO, Hunt MA, Tyagi N. Dual-input tracer kinetic modeling of dynamic contrast-enhanced MRI in thoracic malignancies. J Appl Clin Med Phys 2019; 20:169-188. [PMID: 31602789 PMCID: PMC6839367 DOI: 10.1002/acm2.12740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/29/2022] Open
Abstract
Pulmonary perfusion with dynamic contrast‐enhanced (DCE‐) MRI is typically assessed using a single‐input tracer kinetic model. Preliminary studies based on perfusion CT are indicating that dual‐input perfusion modeling of lung tumors may be clinically valuable as lung tumors have a dual blood supply from the pulmonary and aortic system. This study aimed to investigate the feasibility of fitting dual‐input tracer kinetic models to DCE‐MRI datasets of thoracic malignancies, including malignant pleural mesothelioma (MPM) and nonsmall cell lung cancer (NSCLC), by comparing them to single‐input (pulmonary or systemic arterial input) tracer kinetic models for the voxel‐level analysis within the tumor with respect to goodness‐of‐fit statistics. Fifteen patients (five MPM, ten NSCLC) underwent DCE‐MRI prior to radiotherapy. DCE‐MRI data were analyzed using five different single‐ or dual‐input tracer kinetic models: Tofts‐Kety (TK), extended TK (ETK), two compartment exchange (2CX), adiabatic approximation to the tissue homogeneity (AATH) and distributed parameter (DP) models. The pulmonary blood flow (BF), blood volume (BV), mean transit time (MTT), permeability‐surface area product (PS), fractional interstitial volume (vI), and volume transfer constant (KTrans) were calculated for both single‐ and dual‐input models. The pulmonary arterial flow fraction (γ), pulmonary arterial blood flow (BFPA) and systemic arterial blood flow (BFA) were additionally calculated for only dual‐input models. The competing models were ranked and their Akaike weights were calculated for each voxel according to corrected Akaike information criterion (cAIC). The optimal model was chosen based on the lowest cAIC value. In both types of tumors, all five dual‐input models yielded lower cAIC values than their corresponding single‐input models. The 2CX model was the best‐fitted model and most optimal in describing tracer kinetic behavior to assess microvascular properties in both MPM and NSCLC. The dual‐input 2CX‐model‐derived BFA was the most significant parameter in differentiating adenocarcinoma from squamous cell carcinoma histology for NSCLC patients.
Collapse
Affiliation(s)
- Sang Ho Lee
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Andreas Rimner
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Joseph O Deasy
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Margie A Hunt
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| |
Collapse
|
11
|
Kunze KP, Nekolla SG, Rischpler C, Zhang SH, Hayes C, Langwieser N, Ibrahim T, Laugwitz KL, Schwaiger M. Myocardial perfusion quantification using simultaneously acquired 13 NH 3 -ammonia PET and dynamic contrast-enhanced MRI in patients at rest and stress. Magn Reson Med 2018; 80:2641-2654. [PMID: 29672922 DOI: 10.1002/mrm.27213] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/11/2018] [Accepted: 03/19/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE Systematic differences with respect to myocardial perfusion quantification exist between DCE-MRI and PET. Using the potential of integrated PET/MRI, this study was conceived to compare perfusion quantification on the basis of simultaneously acquired 13 NH3 -ammonia PET and DCE-MRI data in patients at rest and stress. METHODS Twenty-nine patients were examined on a 3T PET/MRI scanner. DCE-MRI was implemented in dual-sequence design and additional T1 mapping for signal normalization. Four different deconvolution methods including a modified version of the Fermi technique were compared against 13 NH3 -ammonia results. RESULTS Cohort-average flow comparison yielded higher resting flows for DCE-MRI than for PET and, therefore, significantly lower DCE-MRI perfusion ratios under the common assumption of equal arterial and tissue hematocrit. Absolute flow values were strongly correlated in both slice-average (R2 = 0.82) and regional (R2 = 0.7) evaluations. Different DCE-MRI deconvolution methods yielded similar flow result with exception of an unconstrained Fermi method exhibiting outliers at high flows when compared with PET. CONCLUSION Thresholds for Ischemia classification may not be directly tradable between PET and MRI flow values. Differences in perfusion ratios between PET and DCE-MRI may be lifted by using stress/rest-specific hematocrit conversion. Proper physiological constraints are advised in model-constrained deconvolution.
Collapse
Affiliation(s)
- Karl P Kunze
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany
| | - Stephan G Nekolla
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | - Christoph Rischpler
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| | | | | | - Nicolas Langwieser
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Tareq Ibrahim
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Karl-Ludwig Laugwitz
- DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany.,Klinikum rechts der Isar der TU München, Department of Cardiology, Munich, Germany
| | - Markus Schwaiger
- Klinikum rechts der Isar der TU München, Department of Nuclear Medicine, Munich, Germany.,DZHK (Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.) partner site Munich Heart Alliance, Munich, Germany
| |
Collapse
|
12
|
Remus CC, Kording F, Arck P, Solano E, Sedlacik J, Adam G, Hecher K, Forkert ND. DCE MRI reveals early decreased and later increased placenta perfusion after a stress challenge during pregnancy in a mouse model. Placenta 2018; 65:15-19. [PMID: 29908637 DOI: 10.1016/j.placenta.2018.03.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 01/27/2023]
Abstract
OBJECTIVES Stress during pregnancy is known to have negative effects on fetal outcome. The purpose of this exploratory study was to examine placental perfusion alterations after stress challenge during pregnancy in a mouse model. MATERIAL AND METHODS Seven Tesla MRI was performed on pregnant mice at embrionic day (ED) 14.5 and 16.5. Twenty dams were exposed to an established acoustic stress challenge model while twenty non-exposed dams served as controls. Placental perfusion was analyzed in dynamic contrast-enhanced (DCE) MRI using the steepest slope model. The two functional placental compartments, the highly vascularized labyrinth and the endocrine junctional zone, were assessed separately. RESULTS Statistical analysis revealed decreased perfusion levels in the stress group at ED 14.5 compared to controls in both placenta compartments. On ED 16.5, the perfusion level increased significantly in the stress group while placenta perfusion in controls remained similar or even slightly decreased leading to an overall increased perfusion in the stress group on ED 16.5 compared to controls. CONCLUSION MR imaging allows noninvasive placenta perfusion assessment in this fetal stress mimicking animal model. In this exploratory study, we demonstrated that stress challenge during pregnancy leads to an initial reduction followed by an increase of placenta perfusion.
Collapse
Affiliation(s)
- Chressen Catharina Remus
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Centre for Radiology and Endoscopy, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
| | - Fabian Kording
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Centre for Radiology and Endoscopy, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Petra Arck
- Department of Obstetrics and Fetal Medicine, Center for Obstetrics and Paediatrics, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Emilia Solano
- Department of Obstetrics and Fetal Medicine, Center for Obstetrics and Paediatrics, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Jan Sedlacik
- Department of Diagnostic and Interventional Neuroradiology, Centre for Radiology and Endoscopy, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Gerhard Adam
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Centre for Radiology and Endoscopy, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Kurt Hecher
- Department of Obstetrics and Fetal Medicine, Center for Obstetrics and Paediatrics, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Nils Daniel Forkert
- Department of Radiology and Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| |
Collapse
|
13
|
Renal Cell Carcinoma Perfusion before and after Radiofrequency Ablation Measured with Dynamic Contrast Enhanced MRI: A Pilot Study. Diagnostics (Basel) 2018; 8:diagnostics8010003. [PMID: 29316711 PMCID: PMC5871986 DOI: 10.3390/diagnostics8010003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 12/28/2017] [Accepted: 01/02/2018] [Indexed: 01/31/2023] Open
Abstract
Aim: To investigate if the early treatment effects of radiofrequency ablation (RFA) on renal cell carcinoma (RCC) can be detected with dynamic contrast enhanced (DCE)-MRI and to correlate RCC perfusion with RFA treatment time. Materials and methods: 20 patients undergoing RFA of their 21 RCCs were evaluated with DCE-MRI before and at one month after RFA treatment. Perfusion was estimated using the maximum slope technique at two independent sittings. Total RCC blood flow was correlated with total RFA treatment time, tumour location, size and histology. Results: DCE-MRI examinations were successfully evaluated for 21 RCCs (size from 1.3 to 4 cm). Perfusion of the RCCs decreased significantly (p < 0.0001) from a mean of 203 (±80) mL/min/100 mL before RFA to 8.1 (±3.1) mL/min/100 mL after RFA with low intra-observer variability (r ≥ 0.99, p < 0.0001). There was an excellent correlation (r = 0.95) between time to complete ablation and pre-treatment total RCC blood flow. Tumours with an exophytic location exhibit the lowest mean RFA treatment time. Conclusion: DCE-MRI can detect early treatment effects by measuring RCC perfusion before and after RFA. Perfusion significantly decreases in the zone of ablation, suggesting that it may be useful for the assessment of treatment efficacy. Pre-RFA RCC blood flow may be used to predict RFA treatment time.
Collapse
|
14
|
Koh TS, Hennedige TP, Thng CH, Hartono S, Ng QS. Understanding K trans: a simulation study based on a multiple-pathway model. Phys Med Biol 2017; 62:N297-N319. [PMID: 28467315 DOI: 10.1088/1361-6560/aa70c9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The transfer constant K trans is commonly employed in dynamic contrast-enhanced MRI studies, but the utility and interpretation of K trans as a potential biomarker of tumor vasculature remains unclear. In this study, computer simulations based on a comprehensive tracer kinetic model with multiple pathways was used to provide clarification on the interpretation and application of K trans. Tissue concentration-time curves pertaining to a wide range of transport conditions were simulated using the multiple-pathway (MP) model and fitted using the generalized kinetic (GK) and extended GK models. Relationships between K trans and plasma flow F p, vessel permeability PS and extraction rate EF p under various transport conditions were assessed by correlation and regression analysis. Results show that the MP model provides an alternative two-tier interpretation of K trans based on the vascular transit time. K trans is primarily associated with F p and EF p respectively, in the slow and rapid vascular transit states, independent of the magnitude of PS. The relative magnitudes of PS and F p only serve as secondary constraints for which K trans can be further associated with EF p and PS in the slow and rapid transit states, respectively.
Collapse
Affiliation(s)
- T S Koh
- Department of Oncologic Imaging, National Cancer Center, 169610, Singapore. Duke-NUS Graduate Medical School, 169857, Singapore
| | | | | | | | | |
Collapse
|
15
|
A novel approach for semi-quantitative assessment of reliability of blood flow values in DCE-CT perfusion. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2016.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
16
|
Mirsadraee S, Weir N, Connolly S, Murchison J, Reid J, Hirani N, Connell M, van Beek E. Feasibility of radiation dose reduction using AIDR-3D in dynamic pulmonary CT perfusion. Clin Radiol 2015; 70:844-51. [DOI: 10.1016/j.crad.2015.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/20/2015] [Accepted: 04/17/2015] [Indexed: 01/05/2023]
|
17
|
|
18
|
Drobyshevsky A, Prasad PV. Placental perfusion in uterine ischemia model as evaluated by dynamic contrast enhanced MRI. J Magn Reson Imaging 2015; 42:666-72. [PMID: 25854322 DOI: 10.1002/jmri.24830] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND To validate DCE MRI method of placental perfusion estimation and to demonstrate application of the method in a rabbit model of fetal antenatal hypoxia-ischemia. METHODS Placental perfusion was estimated by dynamic contrast imaging with bolus injection of Gd-DTPA in 3 Tesla GE magnet in a rabbit model of placental ischemia-reperfusion in rabbit dams at embryonic day 25 gestation age. Placental perfusion was measured using steepest slope method on DCE MRI before and after intermittent 40 min uterine ischemia. Antioxidants (n = 2 dams, 9 placentas imaged) or vehicle (n = 5 dams, 23 placenta imaged) were given systemically in a separate group of dams during reperfusion-reoxygenation. Placental perfusion was also measured in two dams from the antioxidant group (10 placentas) and two dams from the control group (12 placentas) by fluorescent microspheres method. RESULTS While placental perfusion estimates between fluorescent microspheres and DCE MRI were significantly correlated (R(2) = 0.85; P < 0.01), there was approximately 33% systematic underestimation by the latter technique. DCE MRI showed a significant decrease in maternal placental perfusion in reperfusion-reoxygenation phase in the saline, 0.44 ± 0.06 mL/min/g (P = 0.012, t-test), but not in the antioxidant group, 0.62 ± 0.06 mL/min/g, relative to pre-occlusion values (0.77 ± 0.07 and 0.84 ± 0.12 mL/min/g, correspondingly). CONCLUSION Underestimation of true perfusion in placenta by steepest slope DCE MRI is significant and the error appears to be systematic.
Collapse
Affiliation(s)
| | - P V Prasad
- Radiology, NorthShore University HealthSystem, Evanston, IL
| |
Collapse
|
19
|
Automatic differentiation of placental perfusion compartments by time-to-peak analysis in mice. Placenta 2015; 36:255-61. [DOI: 10.1016/j.placenta.2014.12.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 11/04/2014] [Accepted: 12/14/2014] [Indexed: 11/24/2022]
|
20
|
La Fontaine MD, McDaniel LS, Kubicek LN, Chappell RJ, Forrest LJ, Jeraj R. Patient characteristics influencing the variability of distributed parameter-based models in DCE-CT kinetic analysis. Vet Comp Oncol 2015; 15:105-117. [PMID: 25702795 DOI: 10.1111/vco.12143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 01/07/2015] [Accepted: 01/13/2015] [Indexed: 12/17/2022]
Abstract
Kinetic parameter variability may be sensitive to kinetic model choice, kinetic model implementation or patient-specific effects. The purpose of this study was to assess their impact on the variability of dynamic contrast-enhanced computed tomography (DCE-CT) kinetic parameters. A total of 11 canine patients with sinonasal tumours received high signal-to-noise ratio, test-double retest DCE-CT scans. The variability for three distributed parameter (DP)-based models was assessed by analysis of variance. Mixed-effects modelling evaluated patient-specific effects. Inter-model variability (CVinter ) was comparable to or lower than intra-model variability (CVintra ) for blood flow (CVinter :[4-28%], CVintra :[28-31%]), fractional vascular volume (CVinter :[3-17%], CVintra :[16-19%]) and permeability-surface area product (CVinter :[5-12%], CVintra :[14-15%]). The kinetic models were significantly (P<0.05) impacted by patient characteristics for patient size, area underneath the curve of the artery and of the tumour. In conclusion, DP-based models demonstrated good agreement with similar differences between models and scans. However, high variability in the kinetic parameters and their sensitivity to patient size may limit certain quantitative applications.
Collapse
Affiliation(s)
- M D La Fontaine
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - L S McDaniel
- Department of Statistics, University of Wisconsin, Madison, WI, USA
| | - L N Kubicek
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - R J Chappell
- Department of Statistics, University of Wisconsin, Madison, WI, USA
| | - L J Forrest
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - R Jeraj
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| |
Collapse
|
21
|
Effects of guided random sampling of TCCs on blood flow values in CT perfusion studies of lung tumors. Acad Radiol 2015; 22:58-69. [PMID: 25481516 DOI: 10.1016/j.acra.2014.08.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 07/30/2014] [Accepted: 08/01/2014] [Indexed: 11/24/2022]
Abstract
RATIONALE AND OBJECTIVES Tissue perfusion is commonly used to evaluate lung tumor lesions through dynamic contrast-enhanced computed tomography (DCE-CT). The aim of this study was to improve the reliability of the blood flow (BF) maps by means of a guided sampling of the tissue time-concentration curves (TCCs). MATERIALS AND METHODS Fourteen selected CT perfusion (CTp) examinations from different patients with lung lesions were considered, according to different degrees of motion compensation. For each examination, two regions of interest (ROIs) referring to the target lesion and the arterial input were manually segmented. To obtain the perfusion parameters, we computed the maximum slope of the Hill equation, describing the pharmacokinetics of the contrast agent, and the TCC was fitted for each voxel. A guided iterative approach based on the Random Sample Consensus method was used to detect and exclude samples arising from motion artifacts through the assessment of the confidence level of each single temporal sample of the TCC compared to the model. Removing these samples permits to refine the model fitting, thus exploiting more reliable data. Goodness-of-fit measures of the fitted TCCs to the original data (eg, root mean square error and correlation distance) were used to assess the reliability of the BF values, so as to preserve the functional structure of the resulting perfusion map. We devised a quantitative index, the local coefficient of variation (lCV), to measure the spatial coherence of perfusion maps, from local to regional and global resolution. The effectiveness of the algorithm was tested under three different degrees of motion yielded by as many alignment procedures. RESULTS At pixel level, the proposed approach improved the reliability of BF values, quantitatively assessed through the correlation index. At ROI level, a comparative analysis emphasized how our approach "replaced" the noisy pixels, providing smoother parametric maps while preserving the main functional structure. Moreover, the implemented algorithm provides a more meaningful effect in correspondence of a higher motion degree. This was confirmed both quantitatively, using the lCV, and qualitatively, through visual inspection by expert radiologists. CONCLUSIONS Perfusion maps achieved with the proposed approach can now be used as a valid tool supporting radiologists in DCE-CTp studies. This represents a step forward to clinical utilization of these studies for staging, prognosis, and monitoring values of therapeutic regimens.
Collapse
|
22
|
Brix G, Lechel U, Nekolla E, Griebel J, Becker C. Radiation protection issues in dynamic contrast-enhanced (perfusion) computed tomography. Eur J Radiol 2014; 84:2347-58. [PMID: 25480677 DOI: 10.1016/j.ejrad.2014.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 11/11/2014] [Indexed: 11/25/2022]
Abstract
Dynamic contrast-enhanced (DCE) CT studies are increasingly used in both medical care and clinical trials to improve diagnosis and therapy management of the most common life-threatening diseases: stroke, coronary artery disease and cancer. It is thus the aim of this review to briefly summarize the current knowledge on deterministic and stochastic radiation effects relevant for patient protection, to present the essential concepts for determining radiation doses and risks associated with DCE-CT studies as well as representative results, and to discuss relevant aspects to be considered in the process of justification and optimization of these studies. For three default DCE-CT protocols implemented at a latest-generation CT system for cerebral, myocardial and cancer perfusion imaging, absorbed doses were measured by thermoluminescent dosimeters at an anthropomorphic body phantom and compared with thresholds for harmful (deterministic) tissue reactions. To characterize stochastic radiation risks of patients from these studies, life-time attributable cancer risks (LAR) were estimated using sex-, age-, and organ-specific risk models based on the hypothesis of a linear non-threshold dose-response relationship. For the brain, heart and pelvic cancer studies considered, local absorbed doses in the imaging field were about 100-190 mGy (total CTDI(vol), 200 mGy), 15-30 mGy (16 mGy) and 80-270 mGy (140 mGy), respectively. According to a recent publication of the International Commission on Radiological Protection (ICRP Publication 118, 2012), harmful tissue reactions of the cerebro- and cardiovascular systems as well as of the lenses of the eye become increasingly important at radiation doses of more than 0.5 Gy. The LARs estimated for the investigated cerebral and myocardial DCE-CT scenarios are less than 0.07% for males and 0.1% for females at an age of exposure of 40 years. For the considered tumor location and protocol, the corresponding LARs are more than 6 times as high. Stochastic radiation risks decrease substantially with age and are markedly higher for females than for males. To balance the diagnostic needs and patient protection, DCE-CT studies have to be strictly justified and carefully optimized in due consideration of the various aspects discussed in some detail in this review.
Collapse
Affiliation(s)
- Gunnar Brix
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Ursula Lechel
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Elke Nekolla
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Jürgen Griebel
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Christoph Becker
- Department of Clinical Radiology, Grosshadern Clinic, Hospital of the Ludwig-Maximilians University, Marchioninistraße 15, D-81377 Munich, Germany.
| |
Collapse
|
23
|
Forkert ND, Cheng B, Kemmling A, Thomalla G, Fiehler J. ANTONIA perfusion and stroke. A software tool for the multi-purpose analysis of MR perfusion-weighted datasets and quantitative ischemic stroke assessment. Methods Inf Med 2014; 53:469-81. [PMID: 25301390 DOI: 10.3414/me14-01-0007] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 06/11/2014] [Indexed: 01/19/2023]
Abstract
OBJECTIVES The objective of this work is to present the software tool ANTONIA, which has been developed to facilitate a quantitative analysis of perfusion-weighted MRI (PWI) datasets in general as well as the subsequent multi-parametric analysis of additional datasets for the specific purpose of acute ischemic stroke patient dataset evaluation. METHODS Three different methods for the analysis of DSC or DCE PWI datasets are currently implemented in ANTONIA, which can be case-specifically selected based on the study protocol. These methods comprise a curve fitting method as well as a deconvolution-based and deconvolution-free method integrating a previously defined arterial input function. The perfusion analysis is extended for the purpose of acute ischemic stroke analysis by additional methods that enable an automatic atlas-based selection of the arterial input function, an analysis of the perfusion-diffusion and DWI-FLAIR mismatch as well as segmentation-based volumetric analyses. RESULTS For reliability evaluation, the described software tool was used by two observers for quantitative analysis of 15 datasets from acute ischemic stroke patients to extract the acute lesion core volume, FLAIR ratio, perfusion-diffusion mismatch volume with manually as well as automatically selected arterial input functions, and follow-up lesion volume. The results of this evaluation revealed that the described software tool leads to highly reproducible results for all parameters if the automatic arterial input function selection method is used. CONCLUSION Due to the broad selection of processing methods that are available in the software tool, ANTONIA is especially helpful to support image-based perfusion and acute ischemic stroke research projects.
Collapse
Affiliation(s)
- N D Forkert
- Nils Daniel Forkert, Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Bldg. W36, Martinistraße 52, 20246 Hamburg, Germany, E-mail:
| | | | | | | | | |
Collapse
|
24
|
Wang X, Qiao ZW, Zhou ZJ, Zhuang PJ, Zheng S. Postoperative morphine concentration in infants with or without biliary atresia and its association with hepatic blood flow. Anaesthesia 2014; 69:583-90. [PMID: 24749886 DOI: 10.1111/anae.12624] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- X. Wang
- Department of Anesthesiology; Children's Hospital of Fudan University; Shanghai China
| | - Z. W. Qiao
- Department of Radiology; Children's Hospital of Fudan University; Shanghai China
| | - Z. J. Zhou
- Department of Anesthesiology; Children's Hospital of Fudan University; Shanghai China
| | - P. J. Zhuang
- Department of Anesthesiology; Children's Hospital of Fudan University; Shanghai China
| | - S. Zheng
- Department of Surgery; Children's Hospital of Fudan University; Shanghai China
| |
Collapse
|
25
|
Remus C, Sedlacik J, Wedegaertner U, Arck P, Hecher K, Adam G, Forkert N. Application of the steepest slope model reveals different perfusion territories within the mouse placenta. Placenta 2013; 34:899-906. [DOI: 10.1016/j.placenta.2013.06.304] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 06/18/2013] [Accepted: 06/18/2013] [Indexed: 10/26/2022]
|
26
|
Peladeau-Pigeon M, Coolens C. Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications. Phys Med Biol 2013; 58:6111-31. [PMID: 23941800 DOI: 10.1088/0031-9155/58/17/6111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters remains an outstanding problem to address prior to perfusion imaging becoming a widespread standard as a non-invasive quantitative measurement tool. One approach to this validation process has been the development of quality assurance phantoms in order to facilitate controlled perfusion ex vivo. However, most of these systems fail to establish and accurately replicate physiologically relevant capillary permeability and exchange performance. The current work presents the first step in the development of a prospective suite of physics-based perfusion simulations based on coupled fluid flow and particle transport phenomena with the goal of enhancing the understanding of clinical contrast agent kinetics. Existing knowledge about a controllable, two-compartmental fluid exchange phantom was used to validate the computational fluid dynamics (CFD) simulation model presented herein. The sensitivity of CFD-derived contrast uptake curves to contrast injection parameters, including injection duration and flow rate, were quantified and found to be within 10% accuracy. The CFD model was employed to evaluate two commonly used clinical kinetic algorithms used to derive perfusion parameters: Fick's principle and the modified Tofts model. Neither kinetic model was able to capture the true transport phenomena it aimed to represent but if the overall contrast concentration after injection remained identical, then successive DCE-CT evaluations could be compared and could indeed reflect differences in regional tissue flow. This study sets the groundwork for future explorations in phantom development and pharmaco-kinetic modelling, as well as the development of novel contrast agents for DCE imaging.
Collapse
Affiliation(s)
- M Peladeau-Pigeon
- Department of Clinical Engineering, Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, Ontario M5S 3M2, Canada
| | | |
Collapse
|
27
|
Koh TS, Shi W, Thng CH, Ho JTS, Khoo JBK, Cheong DLH, Lim TCC. Assessment of tumor blood flow distribution by dynamic contrast-enhanced CT. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:1504-1514. [PMID: 23625351 DOI: 10.1109/tmi.2013.2258404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A distinct feature of the tumor vasculature is its tortuosity and irregular branching of vessels, which can translate to a wider dispersion and higher variability of blood flow in the tumor. To enable tumor blood flow variability to be assessed in vivo by imaging, a tracer kinetic model that accounts for flow dispersion is developed for use with dynamic contrast-enhanced (DCE) CT. The proposed model adopts a multiple-pathway approach and allows for the quantification of relative dispersion in the blood flow distribution, which reflects flow variability in the tumor vasculature. Monte Carlo simulation experiments were performed to study the possibility of reducing the number of model parameters based on the Akaike information criterion approach and to explore possible noise and tissue conditions in which the model might be applicable. The model was used for region-of-interest analysis and to generate perfusion parameter maps for three patient DCE CT cases with cerebral tumors, to illustrate clinical applicability.
Collapse
Affiliation(s)
- T S Koh
- Department of Oncologic Imaging, National Cancer Center, 169610 Singapore
| | | | | | | | | | | | | |
Collapse
|
28
|
Sourbron SP, Buckley DL. Classic models for dynamic contrast-enhanced MRI. NMR IN BIOMEDICINE 2013; 26:1004-1027. [PMID: 23674304 DOI: 10.1002/nbm.2940] [Citation(s) in RCA: 274] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 02/12/2013] [Accepted: 02/12/2013] [Indexed: 06/02/2023]
Abstract
Dynamic contrast-enhanced MRI (DCE-MRI) is a functional MRI method where T1 -weighted MR images are acquired dynamically after bolus injection of a contrast agent. The data can be interpreted in terms of physiological tissue characteristics by applying the principles of tracer-kinetic modelling. In the brain, DCE-MRI enables measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), blood-brain barrier (BBB) permeability-surface area product (PS) and the volume of the interstitium (ve ). These parameters can be combined to form others such as the volume-transfer constant K(trans) , the extraction fraction E and the contrast-agent mean transit times through the intra- and extravascular spaces. A first generation of tracer-kinetic models for DCE-MRI was developed in the early 1990s and has become a standard in many applications. Subsequent improvements in DCE-MRI data quality have driven the development of a second generation of more complex models. They are increasingly used, but it is not always clear how they relate to the models of the first generation or to the model-free deconvolution methods for tissues with intact BBB. This lack of understanding is leading to increasing confusion on when to use which model and how to interpret the parameters. The purpose of this review is to clarify the relation between models of the first and second generations and between model-based and model-free methods. All quantities are defined using a generic terminology to ensure the widest possible scope and to reveal the link between applications in the brain and in other organs.
Collapse
|
29
|
Rupreht M, Jevtič V, Serša I, Vogrin M, Jevšek M. Evaluation of the tibial tunnel after intraoperatively administered platelet-rich plasma gel during anterior cruciate ligament reconstruction using diffusion weighted and dynamic contrast-enhanced MRI. J Magn Reson Imaging 2012; 37:928-35. [PMID: 23097413 DOI: 10.1002/jmri.23886] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 09/14/2012] [Indexed: 01/11/2023] Open
Abstract
PURPOSE To evaluate effect of platelet-rich plasma gel (PRPG), locally administered during the anterior cruciate ligament (ACL) reconstruction, with two MRI methods. The proximal tibial tunnel was assessed with diffusion weighted imaging (DWI) and with dynamic contrast-enhanced imaging (DCE-MRI). MATERIALS AND METHODS In 50 patients, standard arthroscopic ACL reconstructions were performed. The patients in the PRPG group (n = 25) received a local application of PRPG. The proximal tibial tunnel was examined by DWI and DCE-MRI, which were used to calculate apparent diffusion coefficient (ADC) values, as well as the contrast enhancement gradient (G(enh)) and enhancement factor (F(enh)) values. RESULTS At 1 month, the calculated average ADC value in the PRPG group was significantly lower than in the control group. At 2.5 and at 6 months, G(enh) was significantly higher in the PRPG group. There were no significant differences in F(enh) between the groups at any control examination. CONCLUSION DWI and DCE-MRI measurements indicate a reduced extent of edema during the first postoperative month as well as an increased vascular density and microvessel permeability in the proximal tibial tunnel at 1 and 2.5 postoperative months as the effect of the application of PRPG.
Collapse
Affiliation(s)
- Mitja Rupreht
- Radiology Department, University Medical Center Maribor, Slovenia.
| | | | | | | | | |
Collapse
|
30
|
Brix G, Griebel J, Delorme S. [Dynamic contrast-enhanced computed tomography. Tracer kinetics and radiation hygienic principles]. Radiologe 2012; 52:277-94; quiz 295-6. [PMID: 22476707 DOI: 10.1007/s00117-011-2277-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Technical innovations in multislice computed tomography (CT) allow for larger volume coverage in ever shorter scan times. This progress has stimulated the clinical application of dynamic contrast-enhanced (DCE) CT techniques, which offer the possibility to noninvasively characterize tissue microcirculation in terms of well-defined physiological quantities. This educational review imparts to radiologists the essential physiological terms and definitions as well as the basic tracer kinetic concepts required for the analysis of DCE-CT data. In particular, four different approaches are presented and exemplified by the analysis of representative DCE data: the steepest-gradient method, model-free algebraic deconvolution in combination with the indicator-dilution theory, two-compartment modelling and the so-called adiabatic approximation to the homogeneity model. Even though DCE-CT offers substantial methodological and practical advantages as compared to DCE-MRI (magnetic resonance imaging), there are also two serious and interconnected shortcomings: the low contrast enhancement in relation to the noise level and the high exposure of patients to ionizing radiation. These limiting aspects are considered in detail from a radiation hygienic point of view, emphasizing the basic principles of justification and optimization. Clinically established as well as potential future applications of DCE-CT will be presented in a subsequent paper.
Collapse
Affiliation(s)
- G Brix
- Abteilung für Medizinischen und Beruflichen Strahlenschutz, Fachbereich Strahlenschutz und Gesundheit, Bundesamt für Strahlenschutz, Ingolstädter Landstr. 1, 85764 Neuherberg.
| | | | | |
Collapse
|
31
|
Koh TS, Shi W, Thng CH, Kwek JW, Bisdas S, Khoo JBK. Interpretation and applicability of empirical tissue enhancement metrics in dynamic contrast-enhanced MRI based on a multiple pathway model. Phys Med Biol 2012; 57:N279-94. [DOI: 10.1088/0031-9155/57/15/n279] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
32
|
Rupreht M, Jevtič V, Serša I, Vogrin M, Seruga T, Jevšek M. Quantitative evaluation of the tibial tunnel after anterior cruciate ligament reconstruction using diffusion weighted and dynamic contrast enhanced MRI: a follow-up feasibility study. Skeletal Radiol 2012; 41:569-74. [PMID: 21879337 DOI: 10.1007/s00256-011-1256-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 06/14/2011] [Accepted: 08/08/2011] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The aim of the study was to evaluate the feasibility of two quantitative MRI methods: diffusion weighted imaging (DWI) and dynamic contrast enhanced imaging (DCEI), for follow-up assessment of the tibial tunnel after reconstruction of the anterior cruciate ligament (ACL). MATERIALS AND METHODS Twenty-three patients were examined by MRI at 1 and 6 months following ACL reconstruction. DWI and DCEI were utilized for evaluating the region of interest (ROI) within the proximal part of the tibial tunnel. From the resulting apparent diffusion coefficient (ADC) maps, ADC values were calculated. DCEI data were used to extract the enhancement factor (f(enh)) and the enhancement gradient (g(enh)) for the same ROI. RESULTS Calculated ADC as well as the f(enh) and g(enh) had diminished to a statistically significant extent by 6 months after ACL reconstruction. The average ADC value diminished from 1.48 (10(-3) mm(2)/s) at 1 month to 1.30 (10(-3) mm(2)/s) at 6 months after reconstruction. The average f(enh) value decreased from 1.21 at 1 month to 0.50 at 6 months and the average g(enh) value decreased from 2.01%/s to 1.15%/s at 6 months, respectively. CONCLUSION The study proved feasibility of DWI and DCEI for quantitative assessment of the tibial tunnel at 1 and 6 months after ACL reconstruction. Both methods have the potential for use as an additional tool in the evaluation of new methods of ACL reconstruction. To our knowledge, this is the first time quantitative MRI has been used in the follow-up to the ACL graft healing process.
Collapse
Affiliation(s)
- Mitja Rupreht
- Radiology Department, University Medical Centre Maribor, Ljubljanska 5, 2000 Maribor, Slovenia.
| | | | | | | | | | | |
Collapse
|
33
|
On impulse response functions computed from dynamic contrast-enhanced image data by algebraic deconvolution and compartmental modeling. Phys Med 2012; 28:119-28. [DOI: 10.1016/j.ejmp.2011.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/09/2011] [Accepted: 03/18/2011] [Indexed: 12/21/2022] Open
|
34
|
Tracer kinetic modelling of tumour angiogenesis based on dynamic contrast-enhanced CT and MRI measurements. Eur J Nucl Med Mol Imaging 2010; 37 Suppl 1:S30-51. [PMID: 20503049 DOI: 10.1007/s00259-010-1448-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE Technical developments in both magnetic resonance imaging (MRI) and computed tomography (CT) have helped to reduce scan times and expedited the development of dynamic contrast-enhanced (DCE) imaging techniques. Since the temporal change of the image signal following the administration of a diffusible, extracellular contrast agent (CA) is related to the local blood supply and the extravasation of the CA into the interstitial space, DCE imaging can be used to assess tissue microvasculature and microcirculation. It is the aim of this review to summarize the biophysical and tracer kinetic principles underlying this emerging imaging technique offering great potential for non-invasive characterization of tumour angiogenesis. METHODS In the first part, the relevant contrast mechanisms are presented that form the basis to relate signal variations measured by serial CT and MRI to local tissue concentrations of the administered CA. In the second part, the concepts most widely used for tracer kinetic modelling of concentration-time courses derived from measured DCE image data sets are described in a consistent and unified manner to highlight their particular structure and assumptions as well as the relationships among them. Finally, the concepts presented are exemplified by the analysis of representative DCE data as well as discussed with respect to present and future applications in cancer diagnosis and therapy. RESULTS Depending on the specific protocol used for the acquisition of DCE image data and the particular model applied for tracer kinetic analysis of the derived concentration-time courses, different aspects of tumour angiogenesis can be quantified in terms of well-defined physiological tissue parameters. CONCLUSIONS DCE imaging offers promising prospects for improved tumour diagnosis, individualization of cancer treatment as well as the evaluation of novel therapeutic concepts in preclinical and early-stage clinical trials.
Collapse
|