Diagnostic Value of Sylvian Fissure Hyperechogenicity in Fetal SAH

Transthalamic plane of US in SAH and healthy fetuses. A, The SF and temporal angle are filled with coarse hyperecho in the fetus with SAH (yellow arrows). B, In healthy fetuses, the SF is hypoechoic with narrow and sharp hyperechoic lines on both sides of the posterior midbrain (white arrows). TV indicates third ventricle; CSP, cavity of septum pellucidum; AH, anterior horn of lateral ventricle; T, thalamus, P, mesencephalon; FC, fornix column.

Transventricular plane of US in SAH and healthy fetuses. A, Hyperecho inside the cerebral sulci, such as the subfrontal sulcus, the SF, and the superior temporal sulcus, can be seen in the fetus with SAH, and the boundary is blurred (small yellow arrow). There is an enhanced echo in the cavum veli interpositi (yellow hollow arrow) and symmetric isoechoic or slightly hyperechoic hemorrhagic foci (M) around the parafalx anterior to the sinus confluence. Compression of the cerebral parenchyma is seen. B, In healthy fetuses, a clear hypoecho in the subarachnoid spaces in the SF, the superior temporal sulcus and subfrontal sulcus (small white arrow), and cavum veli interpositi (white hollow arrow); a normal cerebral falx; and no compression are observed in brain parenchyma. CC indicates corpus callosum; CSP, cavity of septum pellucidum; CVI, cavum veli interpositi; PH, posterior horn of lateral ventricle; CP, choroid plexus; AH, anterior horn of lateral ventricle; T, thalamus; M, subdural hemorrhage was suspected.

The transcalvarial plane of US in SAH and healthy fetuses. A, Abnormal hyperecho in the parieto-occipital sulcus of the fetus with SAH, with blurred boundaries (yellow arrows). The enhanced echo and blurred boundary between the superior sagittal sinus and the parenchyma are thickened (yellow hollow arrows). B, In healthy fetuses, only the midline of the brain is clear in the parieto-occipital sulcus, and both sides of the sulcus are filled with clear anechoic CSF (white arrows). The superior sagittal sinus is clearly demarcated from the pericerebral parenchyma, showing a clear isoechoic line (white hollow arrows).

Transbasicranial plane of US in SAH and healthy fetuses. A, The suprasellar cistern and ambient cistern of the fetus with SAH show hyperecho (yellow thick arrow). Compared with the healthy fetus, the cistern was significantly widened and enhanced (yellow thin arrows). B, The suprasellar cistern and ambient cistern of a healthy fetus show hypoechoic or echoless (white arrow). SC indicates suprasellar cistern; TL, temporal lobe; FL, frontal lobe; CV, cerebellar vermis; CH, cerebellar hemisphere; P, mesencephalon.

The midsagittal view of the spine on a sonogram in SAH and healthy fetuses. A, There are uniform thickening and a strong echo in the subarachnoid space between the pia mater spinalis and the arachnoid membranes of fetal SAH (yellow arrows). B, The normal fetal pia mater and arachnoid membrane are relatively close, forming a narrow space (white arrows). MC indicates medullary cone; CE, cauda equina; VA, vertebral arch; VB, vertebral body.