Molar Tooth Sign

Imaging brain A finding on transverse CT and MRI images acquired at the midbrain in patients with Joubert syndrome. The term molar tooth refers to the characteristic appearance of an enlarged and horizontally directed tubular structure on each side of the midline emerging from the midbrain, which is due to an absent decussation of the superior cerebellar peduncular fiber tracts
Imaging urinary bladder A descriptive term referring to the appearance of perivesicular contrast on contrast-enhanced CT in extraperitoneal bladder rupture
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References in periodicals archive ?
Molar tooth sign in fetal brain magnetic resonance imaging leading to the prenatal diagnosis of Joubert syndrome and related disorders.
We could do MRI, molar tooth sign was seen that helped us to diagnose the syndrome.
All three cases had also molar tooth sign in his brain MRI.
Joubert syndrome is a rare genetic disorder that affects the area of the brain that controls balance and coordination (in particular, the cerebellum) and presents a "molar tooth sign" on magnetic resonance imaging.
Joubert syndrome (JS) is a rare genetic disorder that affects the cerebellum, controlling balance, and coordination, and it usually presents a molar tooth sign on magnetic resonance imaging.
Knowledge of the newer classification system and the subtypes is important as it helps to direct and interpret imaging studies based on clinical signs to avoid delay in diagnosis of the hepatic, oculorenal and renal subtypes of JSRDs in patients in whom the molar tooth sign is identified on brain MRI.
Once the molar tooth sign is identified, the brain MRI scan should be reviewed for other associated abnormalities including abnormal configuration and malrotation of the hippocampi, callosal dysgenesis, malformations of cortical development and cephaloceles, which have been described in a sizeable number of patients with JSRDs.
Structural abnormalities of the brain other than molar tooth sign in Joubert syndrome-related disorders.
[1] JS is rare autosomal recessive inherited disorder suspected by hypotonia, ataxia, developmental delay, intellectual disability with distinctive mid-hindbrain malformation (molar tooth sign), ocular abnormalities (e.g., pigmentary retinopathy, oculomotor apraxia, and nystagmus), renal cyst and hepatic fibrosis, hyperpnea alternating with periods of apnea.
A brain MRI showed severe vermis hypoplasia, molar tooth sign, agenesis of corpus callosum, retrocerebellar enlargement (variant Dandy Walker syndrome?) and colpocephaly.
Joubert Syndrome can be identified on axial magnetic resonance imaging as the molar tooth sign (MTS); other criteria include intellectual disability, hypotonia, and often, abnormal respiratory pattern and/or abnormal eye movements.
There are classic imaging findings in Joubert syndrome, including the molar tooth sign and a bat-wing configuration of the fourth ventricle seen on axial MRI or CT.