Optimal differentiation of high- and low-grade glioma and metastasis: a meta-analysis of perfusion, diffusion, and spectroscopy metrics.

INTRODUCTION: To perform a meta-analysis of advanced magnetic resonance imaging (MRI) metrics, including relative cerebral blood volume (rCBV), normalized apparent diffusion coefficient (nADC), and spectroscopy ratios choline/creatine (Cho/Cr) and choline/N-acetyl aspartate (Cho/NAA), for the differentiation of high- and low-grade gliomas (HGG, LGG) and metastases (MTS). METHODS: For systematic review, 83 articles (dated 2000-2013) were selected from the NCBI database. Twenty-four, twenty-two, and eight articles were included respectively for spectroscopy, rCBV, and nADC meta-analysis. In the meta-analysis, we calculated overall means for rCBV, nADC, Cho/Cr (short TE-from 20 to 35 ms, medium-from 135 to 144 ms), and Cho/NAA for the HGG, LGG, and MTS groups. We used random effects model to obtain weighted averages and select thresholds. RESULTS: Overall means (with 95% CI) for rCBV, nADC, Cho/Cr (short and medium echo time, TE), and Cho/NAA were: for HGG 5.47 (4.78-6.15), 1.38 (1.16-1.60), 2.40 (1.67-3.13), 3.27 (2.78-3.77), and 4.71 (3.24-6.19); for LGG 2.00 (1.71-2.28), 1.61 (1.36-1.87), 1.46 (1.20-1.72), 1.71 (1.49-1.93), and 2.36 (1.50-3.23); for MTS 5.06 (3.85-6.27), 1.35 (1.06-1.64), 1.89 (1.72-2.06), 3.14 (1.57-4.72), (Cho/NAA was not available). LGG had significantly lower rCBV, Cho/Cr, and Cho/NAA values than HGG or MTS. No significant differences were found for nADC. CONCLUSIONS: Best differentiation between HGG and LGG is obtained from rCBV, Cho/Cr, and Cho/NAA metrics. MTS could not be reliably distinguished from HGG by the methods investigated.

[Models of intracranial aneurysms for angiographic imaging modalities. A technical note]. / Dirbtiniu intrakranijines aneurizmos modeliu kurimas angiografiniams tyrimams.

OBJECTIVE: To delineate technical aspects of vascular models with intracranial aneurysm in vitro production, suitable for angiographic imaging. MATERIAL AND METHODS: Wax (K2 exact, S-U-CERAMO-CAPS-WAX), Girtl's mass, gelatin, and silicone (Silicone 10015 Den Braven, Elastosil 7683/25, Elite Double 32 Shore-A, Rema-Sil) were used for model production. Construction of models was based on T-shaped plastic tube connections and lost core techniques. Images of rotational angiography, glass tubes with aneurysm, and casts obtained in human specimen were used as samples of cerebral arteries. RESULTS: Technical aspects of vascular models production were delineated in experience of eight silicone models produced. M1 was hand made with basilar tip aneurysm; M2 was obtained according to angiography images with internal carotid artery supraclinoid part bifurcation to anterior and middle cerebral artery aneurysm. BM1 and BM2 casts were made using glass tubes with lateral aneurysm, M3--from T-shaped plastic tubes with lateral aneurysms. M4, M5, and M6 were formed using casts obtained in human specimen with basilar tip aneurysm. CONCLUSIONS: Silicone of two components is practical for casts of cerebral arteries in human specimen production. Gelatinous solution 50 degrees C diluted 1:1 with water can be used for copies of arterial casts production. Wax materials are unsuitable for making casts in a human specimen.