What causes Bowtie appearance in knee meniscus on sagittal MRI?
Let me know in the comments.
Click to reveal the answer
Answer:
The Bowtie appearance represents overlapping anterior and posterior meniscal horns of a normal meniscus or duplicated meniscus on sagittal MRI slices through the meniscal body; its absence (absent bow tie sign) indicates a meniscal tear, particularly bucket-handle tears, due to displacement or disruption of the meniscal body.
Why is it called so?
It is named for the bowtie shape formed by the two dark triangular meniscal horns overlapping centrally on sagittal MRI, resembling a bowtie; the “absent bow tie” specifically refers to failure to visualize this normal configuration.
Pathophysiology
In a normal meniscus, sagittal MRI slices through the body segment display both anterior and posterior horns as two contiguous bowtie-like triangles; tears such as bucket-handle or radial types disrupt this by displacing fragments into the intercondylar notch or creating gaps, resulting in only one or no bowtie visible across expected slices.
Alternative names: Absent bow tie sign
Other associated named signs: Double posterior cruciate ligament sign, truncated meniscus on coronal images
Access all radiology signs posted so far: https://radiogyan.com/radiology-signs/
Improve Content And Help Your Colleagues!
Found an error in the post? Please let us know using our contact page and we will update it with due credits!
If you wish to contribute radiological images for this case (or any other article on the website), you can submit them here and you will be duly credited: Submit radiology case