Porencephaly and Schizencephaly: MRI Findings and Differential Diagnoses

1. CASES Dr. Harsha K J 2nd yr resident, Dept of Radiodiangosis, Baroda Medical College, Baroda

2. CASE 1

3. A sixteen-month old girl presented with seizures and spasticity. • On examination increase in head circumference and developmental delay was detected. • Patient was subjected to MRI.

4. T1W T2W

5. MRI FINDINS • A large CSF intensity cleft extends from the left lateral ventricle to the frontal cortex, lined by gray matter. • Sulcation is abnormal on the right, with thickened cortex and pachygyria.

6. DIFFERENTIAL DIAGNOSES • Porencephaly • Schizencephaly

7. Porencephaly • Porencephaly refers to an area of encephalomalacia, developed in the third trimester or postnatally, which may or may not communicate with the ventricular system, giving the appearance of a dilated ventricle. • A porencephalic cyst is lined by gliotic white matter, not dysplastic hetertopic gray matter . • Porencephaly is usually the end result of a destructive process such as intraparenchymal hemorrhage, infection, or surgery. • The area of destroyed cerebral parenchyma is replaced by CSF.

8. Coronal (a) and sagittal (b) US scans in a 1-day-old term infant with thrombocytopenia show a fairly well-defined cystic lesion within the right insular area (arrow). The margins of the cavity are hyperechoic, a finding suggestive of calcification. A case of Porencephaly (no communication with the ventricles)

9. Axial NCCT image shows that the cystic lesion does not communicate with the lateral ventricles. Note that there are calcifications along the margins of the cavity (arrowheads). These are probably sequelae of a remote infarct in the distribution of the middle cerebral artery.

10. Axial CT Axial long TR/short T/E MRI Wedge shaped csf cleft that extends from the cortex towards the ventricle lined by gliotic white matter in a case of porencephalic cyst

11. T1W T2W

12. DIAGNOSIS • SCHIZENCEPHALY

13. SCHIZENCEPHALY • Schizencephaly or split brain is a neuronal migration anomaly characterized by a gray matter lined CSF filled cleft that extends from the ependymal surface through the white matter to the pial surface of the cerebral cortex. • There is an abnormal gyral pattern adjacent to the cleft. • Types 1. Closed lip 2. Open lip • In closed lip type the walls of the cleft are in apposition and in open lip the walls are separate. In both varieties the cleft is lined by the heterotopic gray matter.

14. The cleft can be unilateral or bilateral, symmetric or asymmetric. • The clefts can be located anywhere, but they commonly occur in the parasylvian regions. • The ventricular system may be enlarged, particularly in patients with the open-lip form of schizencephaly. • Gray-matter heterotopia, polymicrogyria, and arachnoid cysts can be associated with schizencephaly.

15. PATHOPHYSIOLOGY • Several theories have been proposed to explain the etiology, although none is universally accepted. The leading theory indicates that schizencephaly results from an early, focal destruction of the germinal matrix and surrounding brain before the hemispheres are fully formed. • The lesion is most likely related to multiple etiologies, including genetic, toxic, metabolic, vascular, or infectious causes.

16. CLINICAL FEATURES • Variable depending on the size and location of the lesion. • Seizure and spasticity are more common. • Bilateral clefts may have severe mental and psychomotor delay. • Wide clefts are usually correlated with the moderate to severe developmental delay. • Narrow or closed lipped lesions may have hemiplegia and or seizures.

17. IMAGING • USG • CT • MRI

18. ULTRASOUND • In type I, a hyperechoic line extends from the parasylvian region to the anterior portion of the lateral ventricle. The hyperechoic line represents the cortex lining the fused cleft. This type of anomaly is difficult to detect with ultrasound. • In type II, an anechoic band or cavity, representing the fluid-filled cleft, extends from the cortical surface to the lateral ventricle. • The size of the thalamus, caudate, and lenticular nuclei (subcortical gray matter structures) may be decreased. • Other associated anomalies, such as ventricular enlargement, may also be identified.

19. Schizencephaly in a 36-week gestation preterm infant. Coronal US scan shows an open lip cleft (arrows). The left lateral ventricle communicates widely with the subarachnoidspace.

20. CT SCAN • CT scan of closed-lip schizencephaly may show only a slight out pouching at the ependymal surface of the cleft, and a full-thickness cleft may be difficult to identify on CT scan. • The cleft is partially or totally lined by gray matter . • Secondary findings that can be identified on CT scan include hydrocephalus, heterotopia, polymicrogyria, subdural hygromas, and arachnoid cysts. • Using CT, the diagnosis of schizencephaly is sometimes difficult, particularly type I, or closed lip schizencephaly.

21. NCCT HEAD Axial NCCT Head shows bilateral closed lip schizencephaly. CSF cleft is lined by the grey matter.

22. MRI • MRI is the modality of choice for evaluating patients with schizencephaly. MRI better delineates the gray matter lining the cleft, which is the pathognomonic finding in schizencephaly. • Primary findings related to the cleft and secondary findings associated with schizencephaly are identified using MRI. • The ability of MRI pulse sequences to differentiate gray and white matter permits demonstration of gray matter heterotopias in the subcortical white matter beneath the cleft, abnormalities involving the cortex (eg, pachygyria or polymicrogyria) are better delineated on MRI.

23. T2W Axial T2-weighted MRI demonstrates a small open-lip schizencephaly. The septum pellucidum is absent.

24. Axial T1-weighted MR image shows the left cleft (arrows). Three-D MR image shows the communication between the ventricles and the subarachnoid space more clearly.

25. CASE 2

26. A 50yr old male patient presents with acute chest pain after an episode of severe vomiting. • H/O –Breathlessness. • No history of haematemesis. • Patient underwent plain x-ray chest, oesophagogram & CT chest.

29. IMAGING FINDINGS • Extraluminal collection of contrast in the chest • Left sided pleural effusion • Pneumomediastinum • Subcutaneous emphysema

30. DIAGNOSIS • BOERHAAVE SYNDROME

31. BOERHAAVE SYNDROME • Is a spontaneous transmural perforation of the esophagus resulting from a sudden rise in the intraluminal pressure caused by an uncoordinated act of forceful vomiting against a closed cricopharyngeal sphincter or a glottis. • More than 90% of these perforations occur in the left posterolateral wall of the lower third of the esophagus. • The syndrome can also occur after other spontaneous Valsalva-like maneuvers, such as childbirth, coughing, straining during a bowel movement, or heavy lifting. • M>F , Age- 50 to 70yrs

32. CLINICAL PRESENTATION • The classic clinical presentation usually consists of repeated episodes of retching and vomiting, typically in a middle-aged man with recent excessive dietary and alcohol intake. • This is followed by a sudden onset of severe chest pain in the lower thorax and upper abdomen. • Typically, hematemesis is not seen after esophageal rupture, which helps to distinguish it from the more common Mallory-Weiss tear. • Shortness of breath is a common complaint and is due to pleuritic pain or pleural effusion. • Mackler triad defines the classic presentation. It consists of vomiting, lower thoracic pain, and subcutaneous emphysema.

33. IMAGING • Chest radiograph • This is useful in the initial diagnosis because 90% of patients reveal an abnormal finding after perforation. • The most common finding is a Left sided pleural effusion. Other findings may include pneumothorax, hydropneumothorax, pneumomediastinum, subcutaneous emphysema, or mediastinal widening. • The V-sign of Naclerio has been described as a chest radiograph finding in as many as 20% of patients. This involves the presence of radiolucent streaks of air that dissect the fascial planes behind the heart to form the shape of the letter V. It is a fairly specific, although insensitive, radiographic sign of esophageal perforation.

34. Chest X-ray demonstrating pneumomediastinum and Lt pleural effusion

35. Esophagogram • This helps to confirm the diagnosis. • It typically shows extravasation of contrast into the pleural cavity. • The study outlines the length of the perforation and its location, which aids in the decision of whether to use a thoracic or abdominal surgical approach. • Initially, use a water-soluble contrast such as Gastrografin. It has 90% sensitivity. • The use of barium in patients affected with Boerhaave syndrome has been associated with severe mediastinitis. • If the contrast study is negative and the clinical index of suspicion remains high, placing the patient in the left and right lateral decubitus positions often is helpful. The use of barium would then be warranted

36. Oesophageal leak demonstrated with contrast study

37. CT scan • Its function is mainly adjunctive. • It is helpful in patients too ill to tolerate esophagrams. • CECT is ideal for evaluating the esophageal perforation and mediastinitis. It detects wall thickening, perioesoghageal fluid , extraluminal air and effusion. • Visualization of adjacent structures is possible, which helps in narrowing the differential diagnosis in patients with chest pain and vomiting. • The drawback of a CT scan rests in its inability to precisely localize the perforation. • Endoscopy is not commonly used to aid in diagnosis.

38. CT chest demonstrates a left sided hydropneumothorax, pneumomediastinum and esophageal thickening.

39. COMPLICATIONS • Septicemia • Pneumomediastinum • Mediastinitis • Mediastinal abscess • Massive pleural effusion ,empyema & hydropneumothorax • Pneumomediastinum & subcutaneous emphysema. • Acute respiratory distress syndrome

40. TREATMENT • Medical Care: • Intravenous volume resuscitation • Administration of broad-spectrum antibiotics • Surgical Care: .Most physicians advocate surgical intervention if the diagnosis is made within the first 24 hours after perforation. .Direct repair of the rupture and adequate drainage of the mediastinum and pleural cavity provide the best survivalrates.

41. CASE 3

42. A 29 year-old woman presented with generalized seizure and headache. • She underwent CT-Brain and MRI-Brain

43. NCCT-Brain T1W T2W

44. IMAGING FINDINGS • NCCT scan shows a hyperdense well-circumscribed lesion in the right Sylvian fissure. • An axial T1W delineates margin of the lesion & blood products within lesion. • An axial T2W shows the circumferential hemosiderin ring.

45. DIAGNOSIS CAVERNOUS ANGIOMA

46. CAVERNOUS ANGIOMA • Also known as cavernous hemangioma or cavernoma. • It is a lobulated collection of dilated endothelial-lined spaces not separated by significant amount of neural tissue. • No normal brain in lesion is seen. • Hemorrhage in various stages within the lesion with, hemosiderin-stained brain around lesion is present. • 50 to 80% multiple • Age at presentation- 20 to 40 yrs

47. Location • Supratentorial (80%) • Frontal & temporal lobes • Deep cerebral white matter • Corticomedullary junction • Basal ganglia • Posterior fossa • Pons • Cerebellar hemispheres • Extracerebral sites Subarachnoid, intraventricular, subdural , dural sinus& spinal cord

48. IMAGING CEREBRAL ANGIOGRAPHY • Normal or if hemorrhage is present, avascular area with mass effect seen. • Faint blush on late capillary or early venous phase. CT SCAN • Isodense or hyperdense oval or nodular-appearing lesions without mass effect on the surrounding brain parenchyma. • Areas of calcification and hemosiderin deposits are responsible for hyperattenuation on NCCT. • In older lesions, central hypoattenuating nonenhancing areas, which correspond to cystic cavities from resorbed hematoma are seen. • Mild-to-moderate enhancement after the intravenous administration of contrast agent.

49. NCCT CECT NCCT scan shows hyperdense lesion at the gray - white matter junction without any mass effect. The lesion shows enhancement on CECT.

50. MRI • ‘Popcorn-like’ lesion with well delineated complex reticulated core of mixed signal intensities due to hemorrhage in evolution. • Low signal hemosiderin rim completely surrounds lesion. • Hyperintense signal on T2W & strong, homogeneous enhancement after contrast. • Becomes prominent or blooms on T2W & GRE due to magnetic susceptibility. • GRE should always be performed when a solitary ICH lesion is seen, to look for multiple lesions not visible on standard spin-echo studies.