Imaging of Activated T Cells as an Early Predictor of Immune Response to Anti-PD-1 Therapy.

Compelling evidence points to immune cell infiltration as a critical component of successful immunotherapy. However, there are currently no clinically available, noninvasive methods capable of evaluating immune contexture prior to or during immunotherapy. In this study, we evaluate a T-cell-specific PET agent, [18F]F-AraG, as an imaging biomarker predictive of response to checkpoint inhibitor therapy.

Low incidence of pseudoprogression by imaging in newly diagnosed glioblastoma patients treated with cediranib in combination with chemoradiation.

Background: Chemoradiation (CRT) can significantly modify the radiographic appearance of malignant gliomas, especially within the immediate post-CRT period. Pseudoprogression (PsP) is an increasingly recognized phenomenon in this setting, and is thought to be secondary to increased permeability as a byproduct of the complex process of radiation-induced tissue injury, possibly enhanced by temozolomide. We sought to determine whether the addition of a vascular endothelial growth factor (VEGF) signaling inhibitor (cediranib) to conventional CRT had an impact on the frequency of PsP, by comparing two groups of patients with newly diagnosed glioblastoma before, during, and after CRT.

Improved tumor oxygenation and survival in glioblastoma patients who show increased blood perfusion after cediranib and chemoradiation.

Antiangiogenic therapy has shown clear activity and improved survival benefit for certain tumor types. However, an incomplete understanding of the mechanisms of action of antiangiogenic agents has hindered optimization and broader application of this new therapeutic modality. In particular, the impact of antiangiogenic therapy on tumor blood flow and oxygenation status (i.

Vessel architectural imaging identifies cancer patient responders to anti-angiogenic therapy.

Measurement of vessel caliber by magnetic resonance imaging (MRI) is a valuable technique for in vivo monitoring of hemodynamic status and vascular development, especially in the brain. Here, we introduce a new paradigm in MRI termed vessel architectural imaging (VAI) that exploits an overlooked temporal shift in the magnetic resonance signal, forming the basis for vessel caliber estimation, and show how this phenomenon can reveal new information on vessel type and function not assessed by any other noninvasive imaging technique. We also show how this biomarker can provide new biological insights into the treatment of patients with cancer.

Bevacizumab treatment for meningiomas in NF2: a retrospective analysis of 15 patients.

Bevacizumab treatment can result in tumor shrinkage of progressive vestibular schwannomas in some neurofibromatosis 2 (NF2) patients but its effect on meningiomas has not been defined. To determine the clinical activity of bevacizumab against NF2-related meningiomas, we measured changes in volume of meningiomas in NF2 patients who received bevacizumab for treatment of progressive vestibular schwannomas. A radiographic response was defined as a 20% decrease in tumor size by volumetric MRI analysis.

Bevacizumab for progressive vestibular schwannoma in neurofibromatosis type 2: a retrospective review of 31 patients.

Objective: Early studies suggest that bevacizumab treatment can result in tumor shrinkage and hearing improvement for some patients with neurofibromatosis type 2 (NF2). The aim of this study was to report extended follow-up in a larger cohort of similarly treated patients.

Study Design: Retrospective study.

3D Slicer as an image computing platform for the Quantitative Imaging Network.

Quantitative analysis has tremendous but mostly unrealized potential in healthcare to support objective and accurate interpretation of the clinical imaging. In 2008, the National Cancer Institute began building the Quantitative Imaging Network (QIN) initiative with the goal of advancing quantitative imaging in the context of personalized therapy and evaluation of treatment response. Computerized analysis is an important component contributing to reproducibility and efficiency of the quantitative imaging techniques.

Increased survival of glioblastoma patients who respond to antiangiogenic therapy with elevated blood perfusion.

The abnormal vasculature of the tumor microenvironment supports progression and resistance to treatment. Judicious application of antiangiogenic therapy may normalize the structure and function of the tumor vasculature, promoting improved blood perfusion. However, direct clinical evidence is lacking for improvements in blood perfusion after antiangiogenic therapy.

Serial magnetic resonance spectroscopy reveals a direct metabolic effect of cediranib in glioblastoma.

Proton magnetic resonance spectroscopy is increasingly used in clinical studies of brain tumor to provide information about tissue metabolic profiles. In this study, we evaluated changes in the levels of metabolites predominant in recurrent glioblastoma multiforme (rGBM) to characterize the response of rGBM to antiangiogenic therapy. We examined 31 rGBM patients treated with daily doses of cediranib, acquiring serial chemical shift imaging data at specific time points during the treatment regimen.

Spectroscopic imaging with improved gradient modulated constant adiabaticity pulses on high-field clinical scanners.

The purpose of this work was to design and implement constant adiabaticity gradient modulated pulses that have improved slice profiles and reduced artifacts for spectroscopic imaging on 3T clinical scanners equipped with standard hardware. The newly proposed pulses were designed using the gradient offset independent adiabaticity (GOIA, Tannus and Garwood[13]) method using WURST modulation for RF and gradient waveforms. The GOIA-WURST pulses were compared with GOIA-HSn (GOIA based on nth-order hyperbolic secant) and FOCI (frequency offset corrected inversion) pulses of the same bandwidth and duration.

A "vascular normalization index" as potential mechanistic biomarker to predict survival after a single dose of cediranib in recurrent glioblastoma patients.

Early imaging or blood biomarkers of tumor response are desperately needed to customize antiangiogenic therapy for cancer patients. Anti-vascular endothelial growth factor (VEGF) therapy can "normalize" brain tumor vasculature by decreasing vessel diameter and permeability, and thinning the abnormally thick basement membrane. We hypothesized that the extent of vascular normalization will be predictive of outcome of anti-VEGF therapy in glioblastoma.

Imaging hemodynamics.

Microvascular permeability is a pharmacologic indicator of tumor response to therapy, and it is expected that this biomarker will evolve into a clinical surrogate endpoint and be integrated into protocols for determining patient response to antiangiogenic or antivascular therapies. This review discusses the physiological context of vessel permeability in an imaging setting, how it is affected by active and passive transport mechanisms, and how it is described mathematically for both theoretical and complex dynamic microvessel membranes. Many research groups have established dynamic-enhanced imaging protocols for estimating this important parameter.

MRI-measured water mobility increases in response to chemotherapy via multiple cell-death mechanisms.

Numerous pre-clinical and clinical reports have demonstrated that the MRI-measured apparent diffusion coefficient of water (ADC) increases early in the response to a wide variety of anti-cancer therapies. It has been proposed that this increase in ADC generally results from an increase in the tumor extracellular volume fraction leading to a greater degree of unrestricted water motion. Furthermore, an increase in extracellular volume has been ascribed to the cell shrinkage that occurs early in the process of programmed cell death.

Early response of prostate carcinoma xenografts to docetaxel chemotherapy monitored with diffusion MRI.

For many anticancer therapies, it would be desirable to accurately monitor and quantify tumor response early in the treatment regimen. This would allow oncologists to continue effective therapies or discontinue ineffective therapies early in the course of treatment, and hence, reduce morbidity. This is especially true for second-line therapies, which have reduced response rates and increased toxicities.