Whirlpool sign – seen when bowel rotates around its mesentery with the vessels and collapsed bowel creating the whirls. It is found in a number of settings including malrotation complicated by midgut volvulus and caecal volvulus (as above). In midgut volvulus the swirl is counter-clockwise on CT (as if viewed from below) and clockwise on US and is analogous to the corkscrew sign seen on barium studies.
from our tumblr blog: http://radiologysigns.tumblr.com/post/26127010620
from our tumblr blog: http://radiologysigns.tumblr.com/post/26021415703
Corkscrew oesophagus – describes the abnormal segmented appearance of the oesophagus in cases of oesophageal spasm on contrast swallow examination. Normally primary peristalsis extends down the oesophagus as a coordinated wave of contraction and relaxation. In oesophageal spasm multiple segments contract simultaneously and there is failure of normal relaxation. This motility disorder of the oesophagus is most often related to gastro-oesophageal reflux disease and may present with chest pain or dysphagia.
from our tumblr blog: http://radiologysigns.tumblr.com/post/25974612476
Comet tail sign – a CT chest sign of round atelectasis. It consists of spiralling curvilinear opacities extending out to a subpleural “mass”. The rounded nature of the mass-like collapsed portion of lung causes the adjacent bronchovascular bundles to be pulled in resembling a comet tail. Round atelectasis is most commonly the result of asbestos related pleural disease.
from our tumblr blog: http://radiologysigns.tumblr.com/post/25815534459
Lunate dislocation – is an uncommon traumatic wrist injury that requires prompt management and surgical repair. The lunate dislocates by rotating and displacing in the volar direction which results in two cute plain radiograph signs. On an AP film the lunate assumes an abnormal triangular appearance with the apex pointing distally known as the piece of pie sign. The same appearance is also seen in perilunate dislocation. On a lateral film the lunate ‘spills’ forwards creating the spilled teacup sign which is specific for lunate dislocation.
from our tumblr blog: http://radiologysigns.tumblr.com/post/25678867315
Cleft sign – one of the first things to determine when you see an intracranial mass is its location: is it within the brain (intra-axial eg. astrocytoma) or outside the brain (extra-axial eg. meningioma)? Extra-axial masses are typically separated from the brain by a thin cleft of signal or density difference. Classically, this cleft was regarded as a rim of CSF however it is now thought that much of the appearance, particularly on MRI, is due to a non-CSF tumour-brain interface phenomenon. Either way, it is an excellent sign to help differentiate an extra-axial mass. Both the above examples are meningiomas.
from our tumblr blog: http://radiologysigns.tumblr.com/post/25480297279
Signet ring sign – a CT feature of bronchiectasis. As a general rule a bronchus should be no larger than its accompanying pulmonary artery, and if a bronchus is more than 50% larger then this is diagnostic of bronchiectasis. When a dilated bronchiectatic bronchus is viewed in cross-section next to its smaller accompanying pulmonary artery this simulates the appearance of a signet ring, a type of ring once worn by nobles who used them to apply wax seals to their correspondences.
from our tumblr blog: http://radiologysigns.tumblr.com/post/25330514278
Lambda sign – describes the triangular appearance to chorion insinuating between layers of the inter-twin membrane and is an important indicator of dichorionic twin pregnancy. Also known as the twin-peak sign, it is best seen in the first trimester between 10 – 14 weeks. Chorionicity status has major management implications for multifetal pregnancies which makes assessment for this sign essential. The analogous sign in monochorionic twin pregnancy is the T-sign where no chorion extends between the edges of the inter-twin membrane.
from our tumblr blog: http://radiologysigns.tumblr.com/post/25142696652
Segond fracture – small avulsed bone fragment from the lateral margin of the tibial plateau. Avulsion at this location is the result of excessive varus stress on the lateral joint capsule. It is a small but important fracture as it has a very high association with internal derangement of the knee, particularly anterior cruciate ligament tear (right image) which is present in more than 75% of cases.
from our tumblr blog: http://radiologysigns.tumblr.com/post/24998960885