MRI Changes In Status Epilepticus: A Systematic Review In A Tertiary Center.

1. MRI Changes In Status Epilepticus: A Systematic Review In A Tertiary Center. Núria Bargalló, Teresa Lema,Mar Carreño, Antonio Donaire, Javier Aparicio, Iratxe Maestro. Hospital Clínic i Provincial de Barcelona

2. Background • MRI changes due to status epilepticus (SE) often suggest a combination of cytotoxic and vasogenic edema, but it is unclear why only certain patients have MRI changes. • There are numerous case reports in the literature about these status-associated MRI signal changes; however, more extensive series on this subject are rare.

3. Objectives • To study the frequency of MRI changes associated to episodes of status epilepticus (SE) . • To establish associations with different clinical and imaging features including the location of the epileptogencic zone. • To describe the most common MRI findings

4. Methods. • We retrospectively reviewed the charts of 112 adult patients who were discharged from Hospital Clínic, Barcelona, with the diagnosis of Status Epilepticus (SE) from 2000 until 2010. • Subjects included: 27 patients who had MRI performed during the admission • Clinical and demographical data were examined, including: sex, age, previous history of epilepsy, type and etiology of SE and time between onset of SE and MR performance.

5. MRI acquisition • MR examination: 1.5 T scan ( GE and Siemens) . • Sequences: T1WI, T2WI, FLAIR in all patients • DWI : n=24/27 • T1WI post gadolinium: n= 12/27 • Spectroscopy = 4/27 • All MRI data were reviewed by a neuroradiologist with expertise in epilepsy.

6. Results. Clinical and demographic • 14 males and 13 females. • Mean age : 52 years ( range 20-88). • 17/27 ( 63%) No previous diagnosis of epilepsy • 10/27 (37%) have previous diagnosis of epilepsy. • 6/10 with low AED or AED withdrawal. • 4/10 for other provoking factors including sleep deprivation or febrile systemic disease . *mean time between SE and MRI exam: 5,11 days ( range 0-17 days)

7. Types of status • 13/27 Complex partial status epilepticus. • 7/27. Simple motor focal SE, evolving to generalized convulsive in 4 patients. • 7/27 Generalized compulsive status epilepticus

8. MRI findings • Changes related to SE: n=14; (51,8%) ( 3 also have epileptogenic lesion associated ) • Epileptogenic lesion: n=7; ( 25,9%).(Tumor, cysticercosis, ischemic injury) • MRI normal, n=9;( 33,3%) • No correlation between MRI changes and time of MRI exam, etiology of status. • Correlation between MRI changes and EEG findings( p<0.05).

9. MRI changes related to SE ( n=14) • Diffuse involvement: 8/14 p. (57,14%) • Focal involvement : 6/14 p. ( 42,8%) • Limbic system: 9/14 (64%) • neocortex: 7 /14 p (50%) • neocortex and subcortical structures: =3/14 (21,4%) • neocortex, subcortical white matter and basal ganglia-thalamus: 3/14 (21,4%). • + cerebellum : 1/ 14p.(7,1%) • There is a tend between focal involvement and previous epilepsy p =0,06. • Anoxia ( 3p) and infections (2 p) shows diffuse lesions.

10. MRI Characteristics: • Diffuse pattern. (8): - T2WI 7/8 and FLAIR 8/8 - DWI 5/8 - ADC 3/8; ADC 2/8; normal 3/8. - Gyral enhancement 0/5. • Focal pattern. (6) : - T2WI 6/6 and FLAIR 6/6 - DWI 5/5 - ADC 3/5; ADC 2/5. - Gyral enhancement 4/5. - MRS lactate 2/2 * Mean time between SE and MRI exam : ADC = 3,78 days ; ADC = 5,25 days; normal ADC = 3,33 days

11. Focalinvolvement CPSE. Time 3 days. EEG: Right hemispheric spikes and slow wave discharge. Previous diagnosis of epilepsy . Brain trauma with right malacic changes.

12. Diffuseinvolvement CPSE. Time 3 days. EEG: right posterior sharp waves and slow waves, continuous left hemispheric slow waves, BIPLEDs. No previous diagnosis of epilepsy .

13. Focalinvolvement CPSE. Time 8 days. EEG: Left frontal-temporal seizures. Intercritical PLEDS. Previous diagnosis of epilepsy ,low AED.

14. Focal Involvement. CPSE. Time 8 days. EEG: Left frontal-temporal seizures. Intercritical PLEDS. Previous diagnosis of epilepsy ,low AED.

15. Diffuse Involvement. CPSE. Time 4 days. EEG: PLEDS. subclinical seizures. No previous diagnosis of epilepsy. Anoxia

16. Focal Involvement. CPSE. Time 1 day. EEG: Right parietal-occipital continuous spikes. . No previous diagnosis of epilepsy.

17. Diffuse Involvement. Focal SE secondarily generalized. Time 1 day. EEG: Right fronto-temporal continuous spikes. . No previous diagnosis of epilepsy. Liver transplant

18. Varicela-zoster encephalopathy

19. Conclusion • MRI changes in status epilepticus can be observed in about 50% of patients. • Two imaging patterns can be observed: focal or diffuse involvement and in some cases seems to be related with etiology. • Cortical signal abnormalities in T2WI, FLAIR and DWI are the most frequently observed. • Findings related to intra or extracelular edema can be observed in SE