MRI perfusion of brain tumors: any differences between supratentorial and infratentorial?

MRI perfusion of brain tumors: any differences between supratentorial and infratentorial? Poster No.: C-2034 Congress: ECR 2012 Type: Scientific Paper Authors: M. Martucci, S. Gaudino, C. Schiarelli, R. Colantonio, T. Tartaglione, G. Di lella, R. Calandrelli, L. Bonomo, C. Colosimo; Rome/IT Keywords: Neuroradiology brain, MR, MR-Diffusion/Perfusion, Neoplasia DOI: 10.1594/ecr2012/C-2034 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 26

Purpose Although conventional MRI is the modality of choice to detect intracranial masses, the characterization and differentiation of brain tumors (BT) can be challenging. New imaging techniques as diffusion (DWI), perfusion (PWI) and spectroscopy (MRS) may provide 'added value' over conventional MRI in the diagnosis and grading of BT (Fig. 2). PWI has been used to quantify the grade of neoplastic neovascularization and dynamic susceptibility contrast-enhanced (DSC) is the most widely-used clinical perfusion method (Fig. 3). Relative cerebral blood volume (rcbv) has become one of the most important hemodynamic variables used in the characterization of BT Percentage of signal recovery (PSR) is a newer hemodynamic parameter that seems to help in differentiating BT There have been a number of publications investigating MRI perfusion in BT, offering useful cut-off values for the differential diagnosis between gliomas, 1 lymphomas, and metastases and more recent publications reported PSR values 2 (mean, minimum, and maximum) in malignant lesions of the brain. On the other hand, there is still a little clinical experience in the use of perfusion MRI in posterior fossa tumors, due to technical difficulties inherent to this location and to its complex anatomy. As a consequence, few rcbv and PSR data are available for tumors in PF, location where obtaining biopsies is difficult, and significant medical care decisions are taken based only on clinical and imaging data (Fig. 4). Thus, our purposes are: To report PWI parameters (rcbv, PSR) of adult tumors in posterior fossa. To compare these data with those derived from similar supratentorial intra-axial neoplasms. To investigate the reliability of PWI in posterior fossa tumors. Images for this section: Page 2 of 26

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Fig. 5: Purpose Page 6 of 26

Methods and Materials Between January 2005 and January 2011 we retrospectively evaluated MRI of 40 adult Pts: 20 with posterior fossa tumors and 20 with similar supratentorial brain tumors. All lesions were histologically proven (Fig. 6, 7). Our INCLUSION CRITERIA: Intra-axial lesion MRI with DSC PWI Vertebro-basilar arteries and circle of Willis normal in appearance at MRA (within three months from MRI study) Our EXCLUSION CRITERIA: Systemic or brain treatment before MRI Large hemorrhagic component MRI parameters We performed MRI on a 1,5 T scanner (Signa GE, Intera Philiphs), using a 8-channel head coil and a routine pulse sequences protocol for brain tumors (FSE T2-w & T1-w, FLAIR, GRE, thickness/gap 3-4mm/0,3-0,4mm). DWI was always performed (Fig. 8). DSC Perfusion: EPI GRE, TR/TE 1500/35, FOV 28, FA 35, 128x128,4/0.4mm A standard dose of Gadolinium (MultiHance ) was injected intravenously with an injector at a flow rate of 4 or 5 ml/s followed by an injection of 20 ml of saline flush. A preload dose (5-7mL ) was injected 6-7min before PWI Image Processing PWI and DWI were processed on a GE Advantage Windows and a Philips Extended Workspace workstation. ROIs were placed in the area of maximal CBV on perfusion color maps, in the solid portion of the lesion and in the peritumoral areas, carefully avoiding vascular structures (Fig. 9). Page 7 of 26

The following measurements were obtained: Relative CBV (rcbv), minimum and mean percentage of signal intensity recovery (PSRmin, PSRm) Normal white matter (NWM) was used as reference for relative measurements (contralateral middle cerebellar peduncle for posterior fossa lesions). Statistical Analysis We divided lesions into groups according to the location and histological type. Diffuse glioma and pilocytic astrocytoma (Low Grade Glioma, LGG), and anaplastic astocytoma and metastases were evaluated also as a group. Descriptive statistics, including means, minimum-maximum and standard deviations (SD) were calculated for continuous variables. To investigate the differences between groups, Mann Whitney test and Chi Square tests (or Fisher exact test when there were too few cases) were used for quantitative and categorical variables, respectively. Data were analyzed with SPSS 12.0 statistical software for Windows. A p-value #0.05 was considered statistically significant (Fig. 10). Images for this section: Page 8 of 26

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Results Regarding infratentorial data, at a first look, most of the CBV and PSR values seem similar to the supratentorial (Fig. 11), as: the high CBV in HGG the low CBV in PA the low PSR of metastases the high PSR of lymphoma But some data catch our attention, as the high CBV of low grade glioma -even higher than metastases- and the relative high CBV of primary cerebral lymphoma. Comparison between the overall -Supratentorial and Infratentorial- brain tumors shows in Infratentorial (Fig. 12): Lower rcbv of the lesion and peritumoral areas Lower PSRm (0,689 ± 0,638) -3 Lower ADC (1,2 ± 0,5 10 ) Higher PSRmin (0,719± 0,620 ) Comparison between groups shows (Fig. 13): a trend of higher perfusion of all supratentorial groups, except for anaplastic astrocytoma (evaluated alone) lower PSR of infratentorial metastases and higher PSR of infratentorial anaplastic astrocytoma similar rcbv values of primary cerebral lymphoma in posterior fossa and cerebral hemispheres highest PSR of primary cerebral lymphoma in both infratentorial and supratentorial location no statistically significant differences between the groups in term of rcbv (of the lesion and peritumoral areas), PSR and ADC (Mann Whitney test) Case Series: 1-Two cases of metastases from breast cancer, similar in appearance on morphological MRI, both with high CBV values and a low recovery of the curve. The cerebellar lesion shows a lower recovery than the frontal one (Fig. 14). Page 14 of 26

2-Two cases of anaplastic astrocytoma, one in the pons and the other in right frontal lobe; the perfusion looks really similar, showing high CBV values and a good recovery of the curve. The only difference in term of perfusion was the slightly higher CBV of the pontine glioma (Fig.15). 3-Two cases of PA. These lesions tend to have low CBV values and a firstpass curve that crosses the baseline. These characteristics may be explained by the histological profile of the tumoral vascularity and are of relevance in the identification of these tumors (Fig. 16). 4-Two cases of primary cerebral lymphoma: the CBV values and the recovery of the curve look very similar in both location. Notice that the percentage of signal recovery of the supratentorial lesion crosses over the baseline (Fig. 17). Images for this section: Fig. 11 Page 15 of 26

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Fig. 14: Two cases of metastases from breast cancer, similar in appearance on morphological MRI, both with high CBV values and a low recovery of the curve. The cerebellar lesion shows a lower recovery than the frontal one. Page 18 of 26

Fig. 15: Two cases of anaplastic astrocytoma, one in the pons and the other in right frontal lobe; the perfusion looks really similar, showing high CBV values and a good recovery of the curve. The only difference in term of perfusion was the slightly higher CBV of the pontine glioma. Page 19 of 26

Fig. 16: Two cases of PA. These lesions tend to have low CBV values and a firstpass curve that crosses the baseline. These characteristics may be explained by the histological profile of the tumoral vascularity and are of relevance in the identification of these tumors. Page 20 of 26

Fig. 17: Two cases of primary cerebral lymphoma: the CBV values and the recovery of the curve look very similar in both location. Notice that the percentage of signal recovery of the supratentorial lesion crosses over the baseline. Page 21 of 26

Conclusion This is a "hypothesis-generating" study. Although not statistically significant, due to the small number of lesions in our series, these preliminary results support the key role of PWI in evaluating posterior fossa lesions. There is still a little understanding regarding the normal perfusion pattern in posterior fossa, and the lack of comparative areas in the brainstem makes perfusion analysis difficult. In addition we must take into account the technical difficulties in avoiding the multiple vessels (perforating and peripheral) when placing the ROIs in posterior fossa (Fig. 18). Our results show lower blood perfusion (rcbv) in infratentorial than in supratentorial tumors, probably due to the different vascularization. The more "curious" data, for which we still have no explanation are the high rcbv of infratentorial diffuse glioma (3,120 ± 2,0142), which resulted higher than supratentorial, and the relative high rcbv of infratentorial lymphoma (2,96 ± 1,243) PSR showed slight differences between the two locations, both in terms of increased and decreased PSR. Further studies are essential to better interpret PWI data and to assess whether new cut-off values (for PF tumors) are needed to make PWI in PF more reliable in the differential diagnosis (Fig. 19). Images for this section: Page 22 of 26

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References 1. Clin Radiol. 2010 Jan;65(1):15-20. Solitary metastases and high-grade gliomas: radiological differentiation by morphometric analysis and perfusion-weighted MRI. Hakyemez B, Erdogan C, Gokalp G, Dusak A, Parlak M. 2. Radiology. 1999 Jun;211(3):791-8. Glial neoplasms: dynamic contrast-enhanced T2*-weighted MR imaging. Knopp EA, Cha S, Johnson G, Mazumdar A, Golfinos JG, Zagzag D, Miller DC, KellyPJ, Kricheff II. 3. AJNR Am J Neuroradiol. 2011 Jun-Jul;32(6):1004-10. Percentage signal recovery derived from MR dynamic susceptibility contrastimaging is useful to differentiate common enhancing malignant lesions of the brain. Mangla R, Kolar B, Zhu T, Zhong J, Almast J, Ekholm S. 4. AJNR Am J Neuroradiol. 2007 Jun-Jul;28(6):1078-84. Differentiation of glioblastoma multiforme and single brain metastasis by peakheight and percentage of signal intensity recovery derived from dynamicsusceptibility-weighted contrast-enhanced perfusion MR imaging. Cha S, Lupo JM, Chen MH, Lamborn KR, McDermott MW, Berger MS, Nelson SJ, DillonWP. 5. Radiology 2002 Apr;223(1):11-29. Page 25 of 26

Intracranial mass lesions: dynamic contrast-enhanced susceptibility-weightedechoplanar perfusion MR imaging. Cha S, Knopp EA, Johnson G, Wetzel SG, Litt AW, Zagzag D. 6. Radiol Med. 2009 Jun;114(4):645-59. Role of diffusion- and perfusion-weighted MR imaging for brain tumourcharacterisation. Rizzo L, Crasto SG, Moruno PG, Cassoni P, Rudà R, Boccaletti R, Brosio M, DeLucchi R, Fava C. 7. Neuroradiology. 2007 Oct;49(10):795-803. Multimodal MRI in the characterization of glial neoplasms: the combined role ofsinglevoxel MR spectroscopy, diffusion imaging and echo-planar perfusionimaging. Zonari P, Baraldi P, Crisi G. 8. Eur Radiol. 2003 Apr;13(4):758-62. Peritumoral brain edema in intracranial meningiomas evaluated by dynamicperfusionweighted MR imaging: a preliminary study. Uematsu H, Maeda M, Itoh H. 9. J Radiol. 2006 Jun;87(6 Pt 2):807-21. Perfusion MR imaging in brain tumors. Le Bas JF, Grand S, Krainik A, Lefournier V, Tropres I, Rémy C. Personal Information Page 26 of 26