Lisa Hoffman's research while affiliated with The University of Western Ontario and other places

Publications (11)

Article
PurposeChemical exchange saturation transfer MRI using an infusion of glucose (glucoCEST) is sensitive to the distribution of glucose in vivo; however, whether glucoCEST is more related to perfusion or glycolysis is still debatable. We compared glucoCEST to computed tomography perfusion (CTP), [18F] fluorodeoxyglucose positron emission tomography (...
Poster
Full-text available
This work is the first to demonstrate the presence of inflammatory biomarkers in the brain during Duchene Muscular Dystrophy, and model in-vivo the suspected link between cardiac and neurodegeneration using inflammation in a dystrophic disease.
Article
Full-text available
Vascular endothelial growth factor (VEGF) and other pro-angiogenic growth factors have been investigated to enhance muscle tissue perfusion and repair in Duchenne muscular dystrophy (DMD). Current understanding is limited by a lack of functional data following in vivo delivery of these growth factors. We previously used dynamic contrast-enhanced co...
Article
Full-text available
Background Tumor hypoxia is associated with treatment resistance to cancer therapies. Hypoxia can be investigated by immunohistopathologic methods but such procedure is invasive. A non-invasive method to interrogate tumor hypoxia is an attractive option as such method can provide information before, during, and after treatment for personalized ther...
Article
Full-text available
Background The therapeutic efficacy of stereotactic radiosurgery for glioblastoma is not well understood, and there needs to be an effective biomarker to identify patients who might benefit from this treatment. This study investigated the efficacy of computed tomography (CT) perfusion imaging as an early imaging biomarker of response to stereotacti...
Article
Rationale and Objectives To evaluate the improvements in measurements of blood flow (BF), blood volume (BV), and permeability–surface area product (PS) after principal component analysis (PCA) filtering of computed tomography (CT) perfusion images. To evaluate the improvement in CT perfusion image quality with poor contrast-to-noise ratio (CNR) in...
Conference Paper
The purpose of this study was to develop a dynamic contrast-enhanced (DCE) near-infrared spectroscopy (NIRS) technique to characterize tumor physiology. Dynamic data were acquired using two contrast agents of different molecular weights, indocyanine green (ICG) and IRDye 800CW carboxylate (IRDcxb). The DCE curves were analyzed using a kinetic model...
Article
Full-text available
Dynamic contrast-enhanced (DCE) methods are widely used with magnetic resonance imaging and computed tomography to assess the vascular characteristics of tumours since these properties can affect the response to radiotherapy and chemotherapy. In contrast, there have been far fewer studies using optical-based applications despite the advantages of l...
Article
Full-text available
Tumor size is not a reliable marker for the assessment of early antivascular effects of antiangiogenics. In the present study, we used 200-microm in-plane high-resolution dynamic contrast-enhanced computed tomography (DCE-CT) to noninvasively assess the immediate antivascular effects of vandetanib in a subcutaneous human colon cancer (LoVo) xenogra...
Conference Paper
New near-infrared fluorescent agents have improved the depth sensitivity of fluorescence molecular imaging. Preliminary results from preclinical use of a near-infrared emitting, prostate cancer marker displayed adequate tumor contrast by 1 h after intravenous injection.
Article
This study used high-frequency ultrasound (HFU) imaging to assess muscle damage noninvasively in a longitudinal study of 2 transgenic murine models of Duchenne muscular dystrophy (DMD): mdx, which has mutated cytoskeletal protein dystrophin; and udx, which has mutated dystrophin and lacks another cytoskeleton protein, utrophin. The mdx group was fu...

Citations

... The behavior of the CEST effects detected over the 0-30 min observation time could reflect, as well as variations in concentrations associated with tumor-perfusion properties, 46 changes in the pH of the microenvironments in which the agents are distributed. Considering the CEST effect shown by 3OMG ( Figure 4G), the observed response may arise from the extracellular contribution (that decreases upon time, characterized by an acidic pH, thus yielding a smaller ST%, as shown by the in vitro experiments) and the intracellular contribution (that increases upon time, characterized by a higher ST%, as shown by the in vitro experiments). ...
... A treatment based on a different growth factor, angiopoietin 1 (ANG1), combined with VEGF or alone, was also proposed. Notably, administration of ANG1 was shown to enhance muscle perfusion and slow the progression of fibrosis [130]. ...
... The experimental timeline is shown in Fig. 1a. In short, C6 glioma tumor cells were implanted on day 0. A CT perfusion check was performed on day 7 to check if the diameter of the tumor has reached 4 mm [10][11][12]. FDG-PET followed by CT perfusion acquisition was performed between days 11 and 13 after C6 cell implantation. GlucoCEST MRI followed by hyperpolarized [1-13 C] pyruvate MRI experiments was performed on the next day immediately prior to euthanization. ...
... Several types of contrast media have been used to assess 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d M a n u s c r i p t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d M a n u s c r i p t 3 sub-seconds, which are not available in most micro-CT systems. Most studies with these contrast media have been performed with clinical CTs using a bolus injection and dynamic 3D imaging techniques [22,23,25,27,28]. A few studies have been performed with 2D micro-digital subtraction angiography (micro-DSA) [24] or 3D imaging with micro-CT systems [26,29]. ...
... Results from this work support and further demonstrate the generally accepted idea that receptor binding in a specific tissue is dependent on three main factors: (1) how much agent is injected (dose), (2) the efficiency of agent delivery to the tissue (governed primarily by K 1 : proportional to blood flow and vascular permeability), and (3) the 'affinity' of the agent for the receptor (represented as 1/K D here). In principle, all three of these factors could be approximated for any given experiment: (1) dose is obvious, (2) K 1 in a tumor could be extracted from hemodynamic imaging, such as CT Perfusion (Yeung et al 2014), and (3) K D can be approximated in vitro or through in vivo methods as discussed above. As such, the simulation code developed to approximate the level of receptor saturation, which could have significant implications for dosing in 'trace' level molecular imaging experiments as well as personalized drug applications, has been made available to the field in the supplementary files of this manuscript. ...
... Objective, in depth assessment of tissue perfusion using NIRF imaging during creation of the esophagogastric anastomosis in EC surgery is lacking. Therefore, we propose a clinical study that uses NIRF dynamic images to calculate physiologically relevant parameters (blood flow, blood volume, vascular leakage) and generate pseudocolor coded parametric maps using advanced curve analysis and compartmental modelling (adiabatic approximation to tissue homogeneity model, AATH) [45,46] . In addition, this study would be the first to validate imaging-based perfusion assessment of the stomach graft using tissue, serum, and cellular hallmarks of hypo-perfusion and hypoxia during esophagectomy [47] . ...
... Vandetanib is a small molecule TKI that potently inhibits VEGFR-2 and 3, as well as EGFR at a submicromolar concentration [2]. The anti-angiogenic effect of vandetanib has been observed in preclinical tumour models [15,16]. Vandetanib also exhibits direct anti-proliferative effects on tumour cells via EGFR inhibition and, at higher concentrations, inhibition of FGFR and PDGFR [17,18]. ...
... Ultrasound patterns can be correlated with microscopic changes occurring in cases of muscle atrophy, fibrosis, vascular changes, as well as muscle fiber degeneration and regeneration processes [17][18][19][20]. These changes occur, to a greater or lesser extent, when different materials are used to reconstruct VML injuries [11,13,16,[21][22][23]. ...