Hyperechoic foci in the thalamic region imaged via the posterior fontanelle: a potential mimic of thalamic pathology.
BACKGROUND
We have incidentally noted foci of increased thalamic echogenicity (FITE) on cranial sonographic images obtained via the posterior fontanelle (PF) that were not confirmed on images obtained while scanning through the anterior fontanelle (AF). Therefore, we postulated that this is a normal variant of PF imaging rather than true thalamic pathology.


OBJECTIVE
The purpose of this study was to determine the incidence of FITE detected on posterior and anterior fontanelle images.


METHODS
Parasagittal images were obtained bilaterally through the trigone of the lateral ventricles (including the thalami) via both the anterior and posterior fontanelles in 15 consecutive neonates (30 thalami) and evaluated independently by two pediatric radiologists for the presence or absence of FITE. Thalami were graded as grade 0 (no FITE), grade 1 (possible FITE), or grade 2 (definite FITE). Follow-up CT (n = 3) and MR (n = 1) were reviewed.


RESULTS
FITE were absent in 87 % of thalami imaged via the AF, and possible FITE were present in 13 % of these cases. No cases of definite FITE were identified via the AF. However, possible FITE were identified in 33-40 % of thalami and definite FITE were seen in 33 % of thalami imaged via the PF.


CONCLUSIONS
FITE seen only on images obtained through the PF on cranial sonography are a normal finding and should not be attributed to thalamic hemorrhage or ischemia.
Edward B. Singleton Diagnostic Imaging Services, Texas Children's Hospital, Baylor College of Medicine, 6621 Fannin St., MC 2-2521, Houston, TX 77030, USA.
A E
AE
Schlesinger
M M
MM
Munden
L A
LA
Hayman
D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D013788:Thalamus / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods