Taxotere chemosensitivity evaluation in mice prostate tumor: validation and diagnostic accuracy of quantitative measurement of tumor characteristics by MRI, PET, and histology of mice tumor

Quantification of Total and Intracellular Sodium Concentration in Primary Prostate Cancer and Adjacent Normal Prostate Tissue With Magnetic Resonance Imaging

OBJECTIVES

The aim of this study was to measure the tissue sodium concentration (TSC) within tumors and normal prostate in prostate cancer patients, using prostatectomy as pathological criterion standard.

MATERIALS AND METHODS

Fifteen patients with biopsy-proven, magnetic resonance imaging (MRI) visible, intermediate- or high-risk prostate cancer underwent a dedicated research sodium MRI, before treatment with radical prostatectomy. All participants signed written informed consent for this institutional review board-approved prospective study. 3 T MRI acquired using a dedicated multinuclear clamshell transmit coil and a bespoke dual-tuned H/Na endorectal receive coil, with intracellular-sodium imaging acquired using inversion recovery sequences; a phantom-based calibration enabled quantitative sodium maps. Regions of interest were defined for normal peripheral zone (PZ) and transition zone (TZ) and tumor regions, referenced from histopathology maps. A 1-way analysis of variance compared normal and tumor tissue, using Tukey test for multiple comparisons.

RESULTS

Two patients were excluded due to artifact; software error resulted in 1 further intracellular-sodium failure. Fifteen tumors were detected (13 PZ, 2 TZ) in 13 patients: Gleason 3 + 3 (n = 1), 3 + 4 (6), 3 + 5 (2), 4 + 3 (5), 4 + 5 (1). Both mean TSC and intracellular-sodium were significantly higher in normal PZ (39.2 and 17.5 mmol/L, respectively) versus normal TZ (32.9 and 14.7; P < 0.001 and P = 0.02). Mean TSC in PZ tumor (45.0 mmol/L) was significantly higher than both normal PZ and TZ tissue (P < 0.001). Intracellular sodium in PZ tumors (19.9 mmol/L) was significantly higher than normal TZ (P < 0.001) but not normal PZ (P = 0.05). Mean TSC and intracellular-sodium was lower in Gleason ≤3 + 4 tumors (44.4 and 19.5 mmol/L, respectively) versus ≥4 + 3 (45.6 and 20.2), but this was not significant (P = 0.19 and P = 0.29).

CONCLUSIONS

Tissue sodium concentration and intracellular sodium concentrations of prostate tumors were quantified, with PZ tumors demonstrating a significantly increased TSC.

Image guided biodistribution and pharmacokinetic studies of theranostics

Image guided technique is playing an increasingly important role in the investigation of the biodistribution and pharmacokinetics of drugs or drug delivery systems in various diseases, especially cancers. Besides anatomical imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), molecular imaging strategy including optical imaging, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) will facilitate the localization and quantization of radioisotope or optical probe labeled nanoparticle delivery systems in the category of theranostics. The quantitative measurement of the bio-distribution and pharmacokinetics of theranostics in the fields of new drug/probe development, diagnosis and treatment process monitoring as well as tracking the brain-blood-barrier (BBB) breaking through by high sensitive imaging method, and the applications of the representative imaging modalities are summarized in this review.

In vivo imaging of apoptosis in oncology: an update

In this review, data on noninvasive imaging of apoptosis in oncology are reviewed. Imaging data available are presented in order of occurrence in time of enzymatic and morphologic events occurring during apoptosis. Available studies suggest that various radiopharmaceutical probes bear great potential for apoptosis imaging by means of positron emission tomography and single-photon emission computed tomography (SPECT). However, for several of these probes, thorough toxicologic studies are required before they can be applied in clinical studies. Both preclinical and clinical studies support the notion that 99mTc-hydrazinonicotinamide-annexin A5 and SPECT allow for noninvasive, repetitive, quantitative apoptosis imaging and for assessing tumor response as early as 24 hours following treatment instigation. Bioluminescence imaging and near-infrared fluorescence imaging have shown great potential in small-animal imaging, but their usefulness for in vivo imaging in humans is limited to structures superficially located in the human body. Although preclinical tumor-based data using high-frequency-ultrasonography (US) are promising, whether or not US will become a routinely clinically useful tool in the assessment of therapy response in oncology remains to be proven. The potential of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) for imaging late apoptotic processes is currently unclear. Neither 31P MRS nor 1H MRS signals seems to be a unique identifier for apoptosis. Although MRI-measured apparent diffusion coefficients are altered in response to therapies that induce apoptosis, they are also altered by nonapoptotic cell death, including necrosis and mitotic catastrophe. In the future, rapid progress in the field of apoptosis imaging in oncology is expected.

Ultrasound imaging of apoptosis in tumor response: novel preclinical monitoring of photodynamic therapy effects

High-frequency ultrasound is a novel method to detect apoptotic cell death based on changes in cell morphology that cause alterations in the viscoelastic and, consequently, the acoustic properties of cell ensembles and tissues. In this study, we evaluated the first preclinical tumor-based use of high-frequency ultrasound spectroscopy to noninvasively monitor tumor treatment by following xenograft malignant melanoma tumor responses to photodynamic therapy (PDT) in vivo. We observed a time-dependant increase in ultrasound backscatter variables after treatment. The observed increases in spectroscopic variables correlated with morphologic findings, indicating increases in apoptotic cell death, which peaked at 24 hours after PDT. We analyzed the changes in spectral slope and backscatter in relation to apoptosis and histologic variations in cell nuclear size. Changes in spectral slope strongly correlated with the changes in mean nuclear size over time, associated with apoptosis, after PDT (P < 0.05). At 48 hours, a decrease in ultrasound backscatter was observed, which could be explained by an increase in cell nuclear degradation. In summary, we show that high-frequency ultrasound spectroscopic variables can be used noninvasively to monitor response after treatment in a preclinical tumor cancer model. These findings provide a foundation for future investigations regarding the use of ultrasound to monitor and aid the customization of treatments noninvasively based on responses to specific interventions.