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Background: Patients with early-stage, nonbulky classic Hodgkin lymphoma (cHL) undergo intensive posttreatment radiologic surveillance despite having a low risk of disease recurrence. The current study attempted to evaluate the risk of disease recurrence and the value of radiologic surveillance in patients treated with the combination of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) alone who achieved a complete remission (CR) as noted on posttreatment positron emission tomography (PET)., Methods: Forty-seven patients who underwent therapy with interim and/or posttreatment PET scans were evaluated for disease recurrence during ≥ 24 months of follow-up. Their presenting characteristics and imaging results were assessed and interpreted in relation to clinical outcome., Results: All 47 patients were eligible for analysis. The majority of patients were female (35 patients) with a median age of 28 years (range, 17 years-65 years.). The nodular sclerosing subtype was the predominant histology (41 patients). A total of 34 patients were staged with IIA disease, 6 with IA disease, 6 with IIB disease, and 1 with IIEA disease (lung) (according to Cotswolds modification of the Ann Arbor staging system). All patients completed 6 cycles of planned ABVD therapy and achieved a CR. Two had a positive PET scan (1 interim scan and 1 posttreatment scan); both were biopsy-proven sarcoidosis. Two patients developed disease recurrence at 7 months and 24 months, respectively, after negative interim and posttreatment imaging. One case of recurrence was identified through surveillance imaging and the other was identified simultaneously by the patient and surveillance scan. A total of 45 patients experienced a durable CR; 21 had additional unscheduled imaging/workup during surveillance to investigate symptoms or imaging signs of concern., Conclusions: Because of a low risk of disease recurrence, posttreatment radiologic surveillance appears to be unnecessary in patients with early-stage, nonbulky (CD20 negative) cHL who achieve a PET-detected CR with the ABVD combination alone. This will reduce cumulative radiation exposure and health care costs in a predominantly young patient population., (Copyright © 2012 American Cancer Society.)

Early imaging or blood biomarkers of tumor response is needed to customize anti-tumor therapy on an individual basis. This study evaluates the sensitivity and relevance of five potential MRI biomarkers. Sixty nude rats were implanted with human glioma cells (U-87 MG) and randomized into three groups: one group received an anti-angiogenic treatment (Sorafenib), a second a cytotoxic drug [1,3-bis(2-chloroethyl)-1-nitrosourea, BCNU (Carmustine)] and a third no treatment. The tumor volume, apparent diffusion coefficient (ADC) of water, blood volume fraction (BVf), microvessel diameter (vessel size index, VSI) and vessel wall integrity (contrast enhancement, CE) were monitored before and during treatment. Sorafenib reduced tumor CE as early as 1 day after treatment onset. By 4 days after treatment onset, tumor BVf was reduced and tumor VSI was increased. By 14 days after treatment onset, ADC was increased and the tumor growth rate was reduced. With BCNU, ADC was increased and the tumor growth rate was reduced 14 days after treatment onset. Thus, the estimated MRI parameters were sensitive to treatment at different times after treatment onset and in a treatment-dependent manner. This study suggests that multiparametric MR monitoring could allow the assessment of new anti-tumor drugs and the optimization of combined therapies., (Copyright © 2010 John Wiley & Sons, Ltd.)

Assessment of angiogenesis may help to determine tumor grade and therapy follow-up. In vivo imaging methods for non-invasively monitoring microvasculature evolution are therefore of major interest for tumor management. MRI evaluation of blood volume fraction (BVf) and vessel size index (VSI) was applied to assess the evolution of tumor microvasculature in two rat models of glioma (C6 and RG2). The results show that repeated MRI of BVf and VSI - which involves repeated injection of an iron-based MR contrast agent - does not affect either the physiological status of the animals or the accuracy of the MR estimates of the microvascular parameters. The MR measurements were found to correlate well with those obtained from histology. They indicate that microvascular evolution differs significantly between the two glioma models, in good agreement with expression of angiogenic factors (vascular endothelial growth factor, angiopoietin-2) and with activities of matrix metalloproteinases, also assessed in this study. These MRI methods thus provide considerable potential for assessing the response of gliomas to anti-angiogenic and anti-vascular agents, in preclinical studies as well as in the clinic. Furthermore, as differences between the fate of tumor microvasculature may underlie differences in therapeutic response, there is a need for preclinical study of several tumor models., (Copyright (c) 2008 John Wiley & Sons, Ltd.)

Spectra obtained with phase-encoding techniques show phase-shifts varying from voxel to voxel. The procedure allowing voxel-dependent phase-shifts to be compensated is presented. The method has been applied to the characterization of the 1.3-ppm resonance observed in intracerebral tumors in the rat.

Two-dimensional 1H spectroscopic imaging and magnetic resonance imaging were used to study focal ischemia induced by middle cerebral artery occlusion in rats. A water suppressing spin-echo sequence was used at 4.7 T. Phase encoding during the spin-echo delay (TE = 272 ms) yielded an 8 x 8 array of 35 microL voxels. The injured area of the brain had a higher lactate level and markedly lower N-acetyl aspartate, creatine and choline levels than did the non-ischemic regions. The spectroscopic imaging data clearly showed the localization of the infarct, which agreed well with both magnetic resonance imaging and the histological data obtained post-mortem. This study demonstrates the potential usefulness of combining magnetic resonance imaging and 1H spectroscopic imaging for studying animal models of stroke, and indicates the suitability of the technique for further pharmacological approaches.

High-resolution 1H surface coil NMR spectroscopy (MRS) was used to evaluate in vivo the cerebral metabolism changes in rat brain induced by a glial tumor growing in situ. Tumor cells (C6 glioma cells) were stereotaxically placed in the right hemisphere superficially. 1H MRS was performed using 5-mm surface coils implanted over the right hemisphere and the water was suppressed using a binomial sequence. As the intracerebral tumor size increased, there was a marked decrease in the N-acetyl aspartate level and an increase in the 1.3 ppm peak. Edition of this peak showed that lactate increased but lipids increased much more than lactate. Moreover the ratio between the choline-phosphocholine and creatine-phosphocreatine peaks changed. This study demonstrates that high-resolution surface coil 1H MRS can be used to monitor changes in metabolism associated with growth of an experimentally induced rat brain tumor in situ.

Ependymoblastoma tumour bearing mice were treated with sarcosinamide-CNU and compared with untreated mice with regard to tumour growth, pathological examinations and levels of phosphorylated metabolites measured by in vivo nuclear magnetic resonance spectroscopy. The response to the drug was demonstrated by its effect on tumour growth and with pathological examinations. Spectra evolution was different from controls for only four treated tumours out of eight.

To perform in vivo localized proton spectroscopy with water suppression, spin-echo sequences, made of binomial pulses, are commonly used with surface coils. The frequency selective response to such a sequence is also-spatially dependent, that is dependent on the sample shape and on the pulse angle adjustment. It is consequently pointed out in this paper that quantitative analysis for relative peak intensities may be strongly affected by the contribution of the high-flux regions. In vivo proton spectroscopy of rat brain exemplifies this difficulty. It is shown that the use of selective prepulses to suppress high-flux signals may be of poor efficiency depending on chemical shift, while the use of hard nonselective prepulses works for any chemical shift.

31P NMR spin-lattice (T1) and spin-spin (T2) relaxation times of phosphocreatine, ATP, inorganic phosphate, and phosphomonoesters have been measured in vivo at 4.7 T in rat brain and rat brain tumors implanted on nude mice. The relaxation data were acquired using a phase-cycled saturation-recovery spin-echo sequence. The problems associated with the phase modulation of the ATP lines by the homonuclear coupling constants were overcome by using selective refocusing pulses for the T2 measurements. In all the metabolites, large differences (1 to 2 orders of magnitude) are observed between the two relaxation times. T1 values in rat brain tumors are 30 to 90% longer than their counterparts in normal rat brain. T2 values follow the same trend with smaller variations except for phosphocreatine values which seem much less sensitive to the metabolic state of the tissues.