Assessment of some magnetic resonance image factors influencing peritumoral edema of falcine meningiomas

To analyze some magnetic resonance imaging characteristics that impact the formation of peritumoral brain edema in falcine meningiomas. Subjects and methods: A prospective study on 62 patients with falcine meningiomas who underwent navigation-assisted microsurgery between August 2015 and December 2016.

ASSESSMENT OF SOME MAGNETIC RESONANCE IMAGE

FACTORS INFLUENCING PERITUMORAL EDEMA

OF FALCINE MENINGIOMAS

Nguyen Xuan Phuong 1 ; Vu Van Hoe 1

SUMMARY

Objectives: To analyze some magnetic resonance imaging characteristics that impact the

formation of peritumoral brain edema in falcine meningiomas Subjects and methods: A

prospective study on 62 patients with falcine meningiomas who underwent navigation-assisted

microsurgery between August 2015 and December 2016 We evaluated factors related to

peritumoral edema: presence of arachnoid plane, shape of tumor margin and the signal intensity

of the tumor on T2-weighted image) The edema-tumor volume ratio was calculated by the

edema index Results: The average tumor volume was 67.37 ± 66.61 cm³, ranging from 6 to

370 cm³ Peritumoral edema was presented in 28 patients (45.16%) These results suggested

that irregular tumor margins and the absence of arachnoid plane on the magnetic resonance

images could be an important predictive factors that influence the formation of peritumoral

edema in falcine meningiomas (p < 0.05) Conclusion: Irregular tumor margin, absence of

arachnoid plane on the magnetic resonance images can be important predictive factors having

impact on the formation of peritumoral edema in falcine meningiomas

* Keywords: Peritumoral edema; Falcine meningiomas; Magnetic resonance images

INTRODUCTION

Falcine meningioma accounts for 8.5%

[1] of all intracranial meningiomas and was

defined by Cushingas as a meningioma

arising from the falx, it is not completely

correlated to cortex and superior sagittal

sinus

Peritumoral edema is a serious problem

in brain edema impacting on intracranial

pressure Meningiomas are benign and

edema accounted of 60% [8] Many factors related to the development of brain edema have been studied such as tumor size, location, presence of sex hormone receptors and tumor features on magnetic resonance images (MRI) The aims of this

study were: To analyze some magnetic resonance imaging (MRI) characteristics that impact the formation of peritumoral brain edema in falcine meningiomas

1 103 Military Hospital

Corresponding author: Nguyen Xuan Phuong (phuong1030108@yahoo.com.vn)

Date received: 08/07/2019

Date accepted: 12/08/2019

SUBJECTS AND METHODS

This study included 62 patients who

were treated after having an initial diagnosis

of falcine meningioma and underwent

surgery at 103 Military Hospital and Vietduc

Hospital between August 2015 and

December 2016 All patients had MRI

before surgery MRI features data consists

of tumor margin, arachnoid plane and the

T2-weighted image signal intensity were

reported

- The volume of the tumor: The maximum

perpendicular diameters (x and y) of the

tumor and the peritumoral brain edema

(PTBE) were measured on the axial and

sagital image (a and c), and the coronal

diameter (z) was measured on the coronal

images (b and d) The total volume of the

tumor (Vtumor) and the volume of the tumor plus PTBE (Vtumor + edema) were estimated

by using of the following formula for a spheroid: V = 4/3p.x/2.y/2 z/2 EI (Edema Index) = (Vtumor + edema)/(Vtumor)

When the result is under 1, no edema was presented The factors causing edema were also evaluated

MRI was used to examine the correlation between PTBE and the shape of tumor margin We divided the tumor margin into irregular and smooth type We defined

“smooth margin” with nodularity, indentation

or projections in contrast to marginal irregularities

Data was analyzed by using commercial software (SPSS version 22.0 for Windows) The relationship between PTBE and each factor was evaluated by univariate analyses Univariate analysis was used initially to identify possible relationships between the outcome and potentially linked factors by use of the X² test All variables with a significance level of p < 0.05

RESULTS

1 Volume

The average tumor volume was 67.37 ± 66.61 cm³, ranging from 6 to 370 cm³

2 Edema index

Peritumoral brain edema was presented

in 28 patients (45.16%)

3 Tumor margin

Table 1: Relationship between the shape of tumor marginand edema index (EI)

Twenty-nine of the 62 cases showed irregular margin and 33 of the 62 cases showed smooth surface An irregular margin was more likely related to PTBE (p < 0.001)

Table 2: Relationship between the arachnoid plane and EI

The arachnoid plane was absent in 25 cases, and 21 of these 25 cases showed PTBE The arachnoid plane was presented in 37 cases, and only 7 of these 37 cases showed PTBE The results indicated that disappearance of the arachnoid plane was strictly correlated with the development of PTBE (p < 0.05)

5 T2 signal intensity

Table 3: Relationship between the T2-weighted image signal intensity and EI

EI T2 signal intensity

> 0.05

Forty-nine cases had higher T2 signal intensity, and 22 of theses 49 cases showed PTBE The results illustrated that higher-signal intensity accompanied with the

incidence of PTBE not more signifcantly than iso and lower signal intensity (p > 0.05)

DISCUSSION

Previous researches on the relationship

between tumor location and PTBE had

not demonstrated consistent results In

our study, there were 45.16% of patients

with peritumoral edema According to

Takashi Tamiya, PTBE can range from 45

to 92% in different studies Most authors

did not observe a significant correlation

between the age or sex of patient and

PTBE [4, 6]

Our analysis showed two statistical

significant factors for the development of

PTBE These were the disappearance of

the arachnoid plane and the irregular

margin And this was similar to other

authors in the world Lobato [3] reported

that meningiomas with irregular margins

were associated more stricly with PTBE

than those with smooth margins Several

authors agreed that the tumor-brain

interface was one of the most critical

factors in the formation of PTBE

Reseach of Salpietro et al [7] showed

a positive correlation between the grade

of edema and cortical penetration and

noted that the cerebral cortex was disrupted

by invasive meningiomas As part of the

blood-cerebrospinal fluid barrier, the

arachnoid membrane prevents the infiltration

The arachnoid membrane works as a

physiological barrier seems to be a

critical structure Intact leptomeninges

layer and cerebrospinal fluid can help

prevent edema-inducing macromolecules

from infiltrating adjacent normal brain

tissue When the arachnoid layer

disappears, angiogenic factors may act

on the leptomeninges and induce

neovascularization from the pial arteries

to the meningioma Several authors had demonstrated a correlation between the vascular of meningiomas and the grade of PTBE [2]

We studied about relationship between the T2-weighted image signal intensity and peritumoral brain edema by comparing

to the SI of the tumor in T2WI with brain gray matter We realized that the was no correlation between the T2-weighted image and the incidence of PTBE However, we agreed that higher incidence of PTBE had

a tendency of being associated with T2-weighted signal intensities Our result resembled the other studies in the world Ildan et al [5] reported that the signal intensity on T2-weighted scans was correlated with the amount of PTBE They also confirmed that the signal intensity of meningiomas on T2-weighted scans was

a predictor of histological type

CONCLUSION

The edema associated with falcine meningiomas is a potential cause of significant morbidity Edema not only caused the increases in intracranial pressure but also rising risk of surgical trauma to the adjacent brain tissue The peritumoral brain edema impacts the result of operation

Peritumoral edema was present in

28 patients (45.16%) This suggested that irregular tumor margins and absence of arachnoid plane on the MRI could be an important predictive factors, that impacted the formation of peritumoral edema in falcine meningiomas

REFERENCES

1 Chung S.B et al Falx meningiomas:

Surgical results and lessons learned from 68

cases J Korean Neurosurg Soc 2007, 42 (4),

pp.276-280

2 Hou J et al Peritumoral brain edema in

intracranial meningiomas: The emergence of

vascular endothelial growth factor-directed

therapy Neurosurg Focus 2013, 35 (6), p.E2

3 Lobato R.D, Alday R, Gomez P.A, Rivas

J.J, Dominguez J, Cabrera A, Madero S,

Ayerbe J Brain oedema in patients with

intracranial meningioma: Correlation between

clinical, radiological, and histological factors

and the presence and intensity of oedema

Acta Neurochir (Wien) 1996, 138, pp.485-493

4 Nakano T, Asano K, Miura H, Itoh S,

Suzuki S Meningiomas with brain edema:

Radiological characteristics on MRI and

review of the literature Clin Imaging 2002, 26,

pp.243-249

5 Ildan F, Tuna M, Gocer A.I, Boyer B, Bagdatoglu H, Sen O Correlation of the

relationships of brain-tumor interfaces, magneticresonance imaging, andangiographic findings to predict cleavage of meningiomas J

Neurosurg 1999, 91, pp.384-390

6 Tamiya T, Ono Y, Matsumoto K, Ohmoto T Peritumoral brain edema in intracranial meningiomas: E ects of radiological and histological factors Neurosurgery 2001, 49, pp.1046-1051; discussion 1051-1052

7 Salpietro F.M, Alafaci C, Lucerna S, Iacopino D.G Peritumoral edema in meningiomas:

Microsurgical observations of different brain tumor interfaces related to computed tomography

Neurosurgery 1994, 35, pp.638-641

8 Simis A et al Peritumoral brain edema

in benign meningiomas: Correlation with clinical, radiologic, and surgical factors and possible role on recurrence Surg Neuro 2008,

70 (5), pp 471-477; discussion 477