Diagnostic Imaging of Cerebral Toxic & Metabolic Diseases

1. C.N.S.
Toxic & Metabolic Diseases

2. Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

5. Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

6. Toxic & Metabolic Diseases
1-Liver Disease
2-Hypoglycemia
3-Hypoxic Ischemic Encephalopathy
4-Methanol Poisoning
5-Carbon Monoxide

7. 1-Liver Disease :
a) Mechanism
b) Radiographic Findings

8. a) Mechanism :
-Most patients have a history of chronic
cirrhosis resulting in nitrogenous waste
products crossing the blood brain barrier
and causing long-term toxic brain damage

9. b) MRI Findings :
-Bilateral regions of signal hyperintensity in
the lentiform nucleus and substantia nigra
on T1
-These regions of abnormally high signal
intensity at T1 are related to the
accumulation of manganese in patients
with hepatic encephalopathy and may be
encountered also in welders and
recipients of hyperalimentation therapy

10. T1 at the level of the basal ganglia (arrowheads in a) and substantia
nigra (arrows in b) show bilateral symmetric regions of
hyperintensity in these structures

11. Hepatic cirrhosis in a 55-year-old man , T1 shows symmetric
hyperintense foci in the globus pallidus (arrows)

12. 2-Hypoglycemia :
-The extent of brain damage depends on the
severity and duration of hypoglycemia and
clinical presentation includes seizures , focal
neurologic deficits and coma
-Characteristic MR imaging findings of severe
hypoglycemia include bilateral T2
prolongation in the cerebral cortex ,
hippocampi and basal ganglia
-The abnormal areas are typically hyperintense
on diffusion-weighted

13. (a) T2 , (b) diffusion show diffuse hyperintensity and restricted diffusion in
the heads of the caudate nuclei (arrowheads in a) , lentiform nuclei
(arrows in a) and cerebral cortex with sparing of the subcortical white
matter and thalamus

14. 3-Hypoxic Ischemic Encephalopathy :
a) Etiology
b) Radiographic Features

15. a) Etiology :
-HIE of the brain in adults may be the result
of circulatory or respiratory failure from
causes including cardiac arrest , drowning
or asphyxiation

16. b) Radiographic Features :
1-CT :
-Shows diffuse edema , decreased attenuation of
the cortical gray matter with loss of normal gray
matter white matter differentiation and bilateral
decreased attenuation of the basal ganglia and
thalamus (same distribution as hypoglycemia)
but the brainstem and cerebral white matter are
typically spared
-The (reversal sign) may be seen in which there is
higher attenuation in the white matter reversing
the normal relative attenuation between white
matter and gray matter , diffuse cerebral
damage results in a lower attenuation compared
with the cerebellum and brainstem which are
relatively spared resulting in the (white
cerebellum sign)

17. (a) NECT reveals bilaterally symmetric hypoattenuating areas in the thalamus
(arrowheads) , caudate nuclei (black arrows) and globus pallidus (white
arrows) , (b) CT scan obtained through the posterior fossa shows that the
relatively spared cerebellum has higher attenuation than do the damaged
hypoattenuating supratentorial structures (white cerebellum sign)

18. 2-MRI :
-The earliest finding at MR imaging (after 2
hours) is increased signal intensity of the
affected areas on diffusion-weighted images
-T2 shows subtle increased signal intensity and
swelling of the affected areas usually 24
hours or more after the insult
-Delayed postanoxic leukoencephalopathy may
result in diffuse T2 prolongation in the
subcortical white matter

19. (a) FLAIR shows symmetrical T2 prolongation in the bilateral
putamina , heads of the caudate nuclei & to a lesser extent in the
globi pallidi , (b) DWI shows marked diffusion hyperintensity within
the globi pallidi (arrows)

20. (a) T2 shows bilaterally symmetric hyperintense areas in the thalamus
(white arrowheads) , basal ganglia and cerebral cortex , Black
arrowheads = caudate nuclei , arrows = lentiform nuclei , (b) Obtained
at a higher level more clearly depicts diffuse cortical involvement

21. 4-Methanol Poisoning :
-Can present with optic neuritis as the first
symptom
-Hemorrhagic necrosis of the putamen &
white matter edema may follow

22. Methanol poisoning in a 41-year-old man who presented with altered
mental status and retrobulbar pain , CT+C shows hypoattenuating
areas in the lentiform nuclei (arrows) , corpus callosum , and
subcortical deep white matter in the frontal and parietooccipital
regions (arrowheads)

23. 5-Carbon Monoxide :
-Typically causes symmetric T2 prolongation
and restricted diffusion of the globus
pallidus

24. -Carbon monoxide poisoning in a 33-year-old man who was found in a
coma after a suicide attempt , (a) T2 , (b) FLAIR obtained 4 weeks after
the poisoning depict symmetric hyperintense foci in the globus pallidus
(arrows) , symmetric hyperintense areas in the deep white matter
(arrowheads in b) are consistent with delayed leukoencephalopathy