====== Hemosiderin rim ======
The [[Hypointensity]] can be delineated further in the [[gradient echo sequence]] [[T2]]* images due to [[hemosiderin]] deposition in and around the [[cavernous malformation]]
((Campbell PG, Jabbour P, Yadla S, Awad IA. Emerging clinical imaging techniques
for cerebral cavernous malformations: a systematic review. Neurosurg Focus. 2010 
Sep;29(3):E6. doi: 10.3171/2010.5.FOCUS10120. Review. PubMed PMID: 20809764;
PubMed Central PMCID: PMC3708641.
))
((de Champfleur NM, Langlois C, Ankenbrandt WJ, Le Bars E, Leroy MA, Duffau H,
Bonafé A, Jaffe J, Awad IA, Labauge P. Magnetic resonance imaging evaluation of
cerebral cavernous malformations with susceptibility-weighted imaging.
Neurosurgery. 2011 Mar;68(3):641-7; discussion 647-8. doi:
10.1227/NEU.0b013e31820773cf. PubMed PMID: 21164377.
)).

The T2-weighted image show a [[cavernous malformation]] as heterogeneous and "popcorn-like" with a mixed signal intensity core and a hypointense hemosiderin rim.

{{::hemosiderinrim.jpg|}}

T2WI and T2* gradient echo show multiple cavernomas. 
Notice the popcorn appearance with peripheral rim of hemosiderin on the T2WI. 
The lesions are almost completely black on the gradient echo due to blooming artefacts. 
T2* and susceptibility weighted imaging (SWI) markedly increase the sensitivity of MRI to detect small cavernomas.
The five black dots in the left cerebral hemisphere on the T2* are also cavernomas and are not visible on the T2WI.
----
Based on the currently available data in 2017, Dammann et al., concluded that if surgical treatment of cavernoma-related epilepsy is performed, the peri-lesional hemosiderin should be resected. However, cases of eloquent or multiple localization or widespread hemosiderin deposit in which a complete resection is challenging should undergo a specific preoperative work-up
((Dammann P, Schaller C, Sure U. Should we resect peri-lesional hemosiderin
deposits when performing lesionectomy in patients with cavernoma-related epilepsy
(CRE)? Neurosurg Rev. 2017 Jan;40(1):39-43. doi: 10.1007/s10143-016-0797-5. Epub 
2016 Nov 8. Review. PubMed PMID: 27822594.
)).
----
The functional-based resection using intraoperative functional [[brain mapping]] allows safe resection of CA and the peripheral hemosiderin rim located within or close to [[eloquent]] brain areas
((Zanello M, Goodden JR, Colle H, Wager M, Hamer PCW, Smits A, Bello L, Tate M, 
Spena G, Bresson D, Capelle L, Robles SG, Sarubbo S, Rydenhag B, Martino J, Meyer
B, Fontaine D, Reyns N, Schichor C, Metellus P, Colle D, Robert E, Noens B,
Muller P, Rossi M, Nibali MC, Papagno C, Galbarritu L, de Gopegui ER, Chioffi F, 
Bucheli C, Krieg SM, Wostrack M, Yusupov N, Visser V, Baaijen JC, Roux A, Dezamis
E, Mandonnet E, Corns R, Duffau H, Pallud J. Predictors of Epileptic Seizures and
Ability to Work in Supratentorial Cavernous Angioma Located Within Eloquent Brain
Areas. Neurosurgery. 2019 Mar 29. pii: nyz063. doi: 10.1093/neuros/nyz063. [Epub 
ahead of print] PubMed PMID: 30924504.
)).
----
An [[online survey]] composed of 61 items was sent to 26 [[center]]s to establish a [[multicenter]] [[international]] [[retrospective]] [[cohort]] of [[adult]] patients who underwent a surgical [[resection]] as the first-line treatment of a [[supratentorial]] [[cavernous angioma]] located within or close to [[eloquent]] brain area.

272 patients from 19 centers (mean 13.6 ± 16.7 per center) from eight countries were included. The pre-operative management varied significantly between centers and countries regarding the pre-operative functional assessment, the pre-operative epileptological assessment, the first given antiepileptic drug, and the time to surgery. The intra-operative environment varied significantly between centers and countries regarding the use of imaging systems, the use of functional mapping with direct electrostimulations, the extent of resection of the [[hemosiderin rim]], the realization of a post-operative [[functional]] assessment, and the time to post-operative functional assessment. The present survey found a post-operative improvement, as compared to pre-operative evaluations, of the [[functional status]], the ability to work, and the seizure control.

They observed a variety of practice between centers and countries regarding the management of cavernous angioma located within [[eloquent]] regions. Multicentric prospective studies are required to solve relevant questions regarding the management of cavernous angioma-related [[seizure]]s, the timing of surgery, and the optimal extent of [[hemosiderin rim]] resection
((Zanello M, Meyer B, Still M, Goodden JR, Colle H, Schichor C, Bello L, Wager
M, Smits A, Rydenhag B, Tate M, Metellus P, Hamer PW, Spena G, Capelle L,
Mandonnet E, Robles SG, Sarubbo S, Martino González J, Fontaine D, Reyns N, Krieg
SM, Huberfeld G, Wostrack M, Colle D, Robert E, Noens B, Muller P, Yusupov N,
Rossi M, Conti Nibali M, Papagno C, Visser V, Baaijen H, Galbarritu L, Chioffi F,
Bucheli C, Roux A, Dezamis E, Duffau H, Pallud J. Surgical resection of cavernous
angioma located within eloquent brain areas: International survey of the
practical management among 19 specialized centers. Seizure. 2019 Mar 28;69:31-40.
doi: 10.1016/j.seizure.2019.03.022. [Epub ahead of print] PubMed PMID: 30959423.
)).
----
In ten studies comparing extended hemosiderin excision with only lesion resection were identified by searching the English-language literature. Meta-analyses, subgroup analyses and sensitivity analysis were conducted to determine the association between hemosiderin excision and seizure outcome after surgery.

Patients who underwent extended surrounding hemosiderin excision could exhibit significantly improved seizure outcomes compared to patients without hemosiderin excision. However, further well-designed prospective multiple-center RCT studies are still needed
((Ruan D, Yu XB, Shrestha S, Wang L, Chen G. The Role of Hemosiderin Excision in
Seizure Outcome in Cerebral Cavernous Malformation Surgery: A Systematic Review
and Meta-Analysis. PLoS One. 2015 Aug 25;10(8):e0136619. doi:
10.1371/journal.pone.0136619. eCollection 2015. PubMed PMID: 26305879.)).


Previous works showed that extent of resection and its surrounding [[hemosiderin]] rim were found to consistently correlate with a more favorable post-operative seizure-free outcome
((Stavrou I, Baumgartner C, Frischer JM, Trattnig S, Knosp E. Long-term seizure 
control after resection of supratentorial cavernomas: a retrospective
single-center study in 53 patients. Neurosurgery. 2008 Nov;63(5):888-96;
discussion 897. doi: 10.1227/01.NEU.0000327881.72964.6E. PubMed PMID: 19005379.))
((Kim W, Stramotas S, Choy W, Dye J, Nagasawa D, Yang I. Prognostic factors for post-operative seizure outcomes after cavernous malformation treatment. J Clin Neurosci. 2011 Jul;18(7):877-80. doi: 10.1016/j.jocn.2010.12.008. Epub 2011 May
10. Review. PubMed PMID: 21561775.)).

Patients with short duration of [[epilepsy]] associated with [[cavernous malformation]]s could benefit greatly from complete resection of hemosiderin rim and cavernous malformations
((Jin Y, Zhao C, Zhang S, Zhang X, Qiu Y, Jiang J. Seizure outcome after surgical resection of supratentorial cavernous malformations plus hemosiderin rim in patients with short duration of epilepsy. Clin Neurol Neurosurg. 2014
Apr;119:59-63. doi: 10.1016/j.clineuro.2014.01.013. Epub 2014 Jan 25. PubMed PMID: 24635927.)).

High field intraoperative MRI imaging (iopMRI) and neuronavigation might play a crucial role to achieve both goals
((Xie HW, Wang DM, Yuan QG, Sha C, Yang YM, Jiang HZ. [The utility of
neuronavigation in the microsurgery for cerebral cavernous malformations].
Zhonghua Wai Ke Za Zhi. 2011 Aug 1;49(8):712-5. Chinese. PubMed PMID: 22168935.
)).

26 patients (14 female, 12 male, mean age 39·1 years, range: 17-63 years) with CM related epilepsy were identified. Eighteen patients suffered from drug resistant epilepsy (69·2%). Mean duration of epilepsy was 11·9 years in subjects with drug resistant epilepsy (n = 18) and 0·3 years in subjects presenting with first-time seizures (n = 8). 

24 lesionectomies and two lesionectomies combined with extended temporal resections were performed.

Seven lesions were located extratemporally. 

Complete CM removal was documented by postsurgical MRI in all patients. As direct consequence of iopMRI, refined surgery was necessary in 11·5% of patients to achieve complete cavernoma removal and in another 11·5% for complete resection of additional adjacent epileptogenic cortex. Removal of the hemosiderin rim was confirmed by iopMRI in 92% of patients. Two patients suffered from mild (7·7%) and one from moderate (3·8%) visual field deficits. Complete seizure control (Engel class 1A) was achieved in 80·8% of patients with a mean follow-up period of 47·7 months
((Sommer B, Kasper BS, Coras R, Blumcke I, Hamer HM, Buchfelder M, Roessler K.
Surgical management of epilepsy due to cerebral cavernomas using neuronavigation 
and intraoperative MR imaging. Neurol Res. 2013 Oct 23:0. [Epub ahead of print]
PubMed PMID: 24070413.
)).

===== References =====