Assessment of sodium (23Na) brain MRI at 3T - preliminary results.

Purpose: The purpose of this work was to establish a database of tissue sodium concentration (TSC) in the normal brain of healthy volunteers. Tissue sodium concentration can be used as a sensitive marker of tissue viability in stroke or radiation therapy monitoring. Material and methods: Thirty-seven volunteers were scanned with a 23Na protocol in the span of one year; within this group, 29 studies were of acceptable quality. The study was approved by the Local Bioethics Committee. Data were acquired during a single magnetic resonance (MR) scanner session. The single scanner session consisted of 23Na 3D radial gradient echo (GRE) acquisition, MPRage, SPACE-FLAIR, and Resolve-DTI. MPRage images were segmented to obtain masks of the grey matter (GM), white matter (WM), and cerebrospinal fluid (CSF), which were registered to the sodium image space for image analysis. Images were transformed into TSC maps - a signal calibration curve obtained from the reference phantom of known sodium concentration and known relaxation time. Results: The collected data were analysed in 2 different ways: volunteers were divided by sex and by age. No significant differences in TSC were found between sexes. In all comparisons there was a significant difference in TSC between younger and older volunteers. In healthy volunteers mean TSC were as follows: GM 33.21 ± 4.76 mmol/l, WM 28.41 ± 4.03 mmol/l and for CSF 41.3 ± 6.69 mmol/l. Conclusions: This preliminary work is a base for further work with sodium imaging in brain lesions. The entirety of the col-lected data will be useful in the future as a baseline brain TSC for comparison to values obtained from pathologies.

The diagnostic challenge of lack of choline level elevation on 1H-MR spectroscopy in grade II-III gliomas.

The accurate diagnosis of brain tumour is very important in modern neuro-oncology medicine. Magnetic resonance spectroscopy (MRS) is supposed to be a promising tool for detecting cancerous lesions. However, the interpretation of MRS data is complicated by the fact that not all cancerous lesions exhibit elevated choline (Cho) levels. The main goal of our study was to investigate the lack of Cho lesion /Cho ref elevation in the population of grade II-III gliomas. 89 cases of gliomas grade II and III were used for the retrospective analysis - glioma (astrocytoma or oligodendroglioma) grade II (74 out of 89 cases [83%]) and III (15 out of 89 cases [17%]) underwent conventional MRI extended by MRS before treatment. Histopathological diagnosis was obtained either by biopsy or surgical resection. Gliomas were classified to the group of no-choline elevation when the ratio of choline measured within the tumour (Cho lesion ) to choline from NABT (Cho ref ) were equal to or lower than 1. Significant differences were observed between ratios of Cho lesion /Cr lesion calculated for no-choline elevation and glial tumour groups as well as in the NAA lesion /Cr lesion ratio between the no-choline elevation group and glial tumour group. With consistent data concerning choline level elevation and slightly lower NAA value, the Cho lesion /NAA lesion ratio is significantly higher in the WHO II glial tumour group compared to the no-choline elevation cases ( p < 0.000). In the current study the results demonstrated possibility of lack of choline elevation in patients with grade II-III gliomas, so it is important to remember that the lack of elevated choline levels does not exclude neoplastic lesion.

In-bore MR prostate biopsy - initial experience.

INTRODUCTION: The introduction of multiparametric MRI (mpMRI) has been a breakthrough in the diagnosis of noninvasive clinically significant prostate cancer. Currently, MR-guided prostate biopsy (in-bore biopsy) is the only biopsy method that uses real-time MRI in patients with suspected prostate cancer. The aim of the study was a retrospective analysis of the correlation between MRI results and histological findings of prostate samples suspected of malignancy, which were taken during MRI-guided biopsy. MATERIAL AND METHODS: Thirty-nine patients with 57 lesion biopsies were enrolled in the study. Patients were aged 48-84 years (mean age 67.2 ± 9.4 years). RESULTS: Cancer was histologically confirmed in 24 lesions, including primary cancer in 14 lesions and local recurrence in 10 lesions. Cancer was not detected in the remaining lesions (n = 33). Malignancy was confirmed in 90% of lesions previously reported as PI-RADS 5. Only one Prostate Imaging and Reporting and Data System (PI-RADS 5) lesion was histologically negative (prostatitis). Cancer was detected in 50% of lesions defined as PI-RADS 4. Cancer cells were not found in any of 23 lesions defined as PI-RADS 3 (53.5%). Most of the lesions assessed as PI-RADS 3 were located in the transitional zone (n = 19). Only four PI-RADS 3 lesions were found in the peripheral zone. Large lesions or lesions feasible for cognitive TRUS biopsy were not referred for MRI biopsy, which resulted in a higher proportion of lesions assessed as PI-RADS 3. Fourteen lesions suspected of local recurrence were assessed in our study. Cancer was found in approximately 72% of the lesions. CONCLUSIONS: Performing prostate biopsy under the guidance of real-time MRI allows precise collection of material for histological examination (even from a very small lesion). As a result, both primary cancer and local recurrence after previous radiotherapy of prostate cancer can be confirmed.