Answer for BIR CoW 28 Sep 2025
PROMINENT CRISTA TERMINALIS
Findings
Evidence of a linear/nodular hypointense structure is noted within the right atrial base, attached to the posterior septal wall, measuring approximately 9.7 × 5.7 mm.
Discussion
The crista terminalis is a normal anatomical structure of the right atrium, seen as a smooth muscular ridge along its superior aspect. It represents the developmental remnant of the right valve of the sinus venosus and serves as a landmark dividing the right atrium into two distinct portions — the smooth posteromedial and the trabeculated anterolateral segments.
Under usual circumstances, the crista terminalis is not visualized on standard transthoracic echocardiography or non-gated CT chest scans. However, in some individuals, it may appear prominent, potentially mimicking a right atrial mass or thrombus, leading to diagnostic confusion.
Characteristic echocardiographic features of a prominent crista terminalis include:
Other normal anatomical structures and variants within the heart that may appear as band-like formations include the taenia sagittalis, Chiari network, coumadin ridge, moderator band, papillary muscles, and chordae tendineae.
A multi-modality imaging approach (including echocardiography, CT, and MRI) is often employed to accurately characterize these structures and differentiate them from pathological lesions.
On MRI, the principal differentiating feature between a normal anatomical variant and a pathological lesion lies in signal intensity and enhancement characteristics:
Findings
Evidence of a linear/nodular hypointense structure is noted within the right atrial base, attached to the posterior septal wall, measuring approximately 9.7 × 5.7 mm.
Discussion
The crista terminalis is a normal anatomical structure of the right atrium, seen as a smooth muscular ridge along its superior aspect. It represents the developmental remnant of the right valve of the sinus venosus and serves as a landmark dividing the right atrium into two distinct portions — the smooth posteromedial and the trabeculated anterolateral segments.
Under usual circumstances, the crista terminalis is not visualized on standard transthoracic echocardiography or non-gated CT chest scans. However, in some individuals, it may appear prominent, potentially mimicking a right atrial mass or thrombus, leading to diagnostic confusion.
Characteristic echocardiographic features of a prominent crista terminalis include:
- Location: Along the posterolateral wall of the right atrium near the superior vena cava, following the course connecting the superior and inferior vena cavae.
- Margins: Smooth and rounded.
- Echogenicity: Isoechoic to the adjacent myocardium.
- Dynamic behavior: Phasic variation in size, becoming thicker during atrial systole.
Other normal anatomical structures and variants within the heart that may appear as band-like formations include the taenia sagittalis, Chiari network, coumadin ridge, moderator band, papillary muscles, and chordae tendineae.
A multi-modality imaging approach (including echocardiography, CT, and MRI) is often employed to accurately characterize these structures and differentiate them from pathological lesions.
On MRI, the principal differentiating feature between a normal anatomical variant and a pathological lesion lies in signal intensity and enhancement characteristics:
- Normal variants (such as the crista terminalis) typically demonstrate isointensity and similar enhancement to the adjacent normal myocardium.
- Pathological lesions usually exhibit altered signal intensity and distinct enhancement patterns, reflecting their abnormal tissue composition.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
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Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!