Types of Hypoxia

Type of hypoxia	Pathophysiology	Arterial PO2	O2 content of arterial blood	Examples
Anemic Hypoxia	Due to reduced O2 carrying capacity	Normal	Reduced	Anemia (Reduced RBC, Reduced Hb) CO poisoning
Hypoxic Hypoxia	Inadequate gas exchange	Reduced	Reduced	High altitude Respiratory disease
Histotoxic Hypoxia	Inability of cells to utilize available O2	Normal	Normal	Cyanide poisoning
Stagnant Hypoxia	due to slow circulation	Normal	Normal	Circulatory Shock Congestive heart failure

SIGNS IN RADIOLOGY

• Accordion sign : Appearance of bowel that may be seen with pseudomembranous colitis.


• Air crescent sign : Appearance of cavitation that may be seen with invasive apergillosis (see also Monod sign).


• Anteater’s nose sign : Sign of calcaneonavicular tarsal coalition.


• Apple Core lesion : Circumferential narrowing of the lumen secondary to colon cancer.


• Ball on tee sign : Sign of papillary necrosis on IVU.


• Banana sign : Seen on antenatal US and refers to a banana-shaped configuration of the cerebellum. Associated with neural tube defects.


• Bat wing appearance (chest) : Classic chest radiography finding for pulmonary edema.


• Bat wing appearance (neuro) : Appearance of 4th ventricle that may be seen with Joubert syndrome.


• Bergman’s coiled catheter sign : Sign of ureteral transitional cell carcinoma when a catheter coils in region of neoplasm (see also Goblet sign).


• Bird’s beak : Narrowing of the esophagus in achalasia.


• Bird’s beak sign or bird of prey sign : Narrowing of the colon in cecal volvulus.


• Blade of grass : Paget disease.


• Bone in bone sign : Appearance of spine that may be seen osteopetrosis.


• Boot-shaped Heart : Appearance of heart that may be seen with tetralogy of Fallot.


• Boxcar ventricles : Appearance of frontal horns that may be seen in Huntington’s disease.


• Bracket Calcification  : Corpus Callosum Lipoma


• Breast in a breast : Term used to describe Fibroadenolipomas.


• Bulging fissure sign : Bulging of a pulmonary fissure. Most commonly associated with Klebsiella pneumonia.


• Bullet carpal bones : Appearance of carpal bones that may be seen with mucopolysaccharidoses.


• Butterfly vertebrae : Results from failure of fusion of the lateral halves of the vertebral body because of persistent notochondal tissue between them.


• C sign : Sign of talocalcaneal tarsal coalition.


• Cake kidney : All renal tissue is fused into one pelvic mass and gives rise to two separate ureters which enter the bladder in normal relationship.


• Canoe paddle ribs : Appearance of ribs that may be seen with mucopolysaccharidoses.


• Celery stalking : Irregular appearance of metaphyses in patients with rubella. Also used to describe metaphyses in patients with osteopathia striata.


• Central dot sign : Sign of Caroli’s disease.


• Champagne sign : Specific but not commonly seen ultrasound finding for emphysematous cholecystitis.


• Cloverleaf skull : Appreance of the skull that may be seen with thanatophoric dysplasia.


• Cluster of grapes : Appearance that may be seen with pneumatosis cystoides coli.


• Cobra head sign : Dilatation of the distal ureter which may be seen in patients with ureteroceles.


• Coffee bean sign : Sigmoid volvulus.


• Collar sign : Sign of diaphragmatic rupture.


• Comet sign : Sign to differential a phlebolith from a ureteral stone. Calcified phlebolith represents the comet nucleus and the adjacent, tapering, noncalcified portion of the vein is the comet tail (also see soft-tissue rim sign).


• Comet tail sign : Produced by the distortion of vessels and bronchi that lead to an adjacent area of round atelectasis.


• Cord sign : Sign of intracranial dural sinus thrombosis.


• Corkscrew collaterals : Appearance of collaterals that may be seen in patients with Buerger disease.


• Corkscrew sign : Upper GI series sign of midgut volvulus.


• Corduroy appearance : Appearance of thickening trabeculations seen in intraosseous hemangiomas of the spine. See also polka-dot pattern.


• Crazy-paving sign : Nonspecific appearance consisting of linear network or reticular pattern with areas of ground-glass opacification. Classically associated with pulmonary alveolar proteinosis.


• Crossover sign : Anterior acetabular rim is projected laterally relative to the same point of the posterior rim in the superolateral aspect of the acetabulum. See with pincer type femoroacetabular impingement.


• Cyclops lesion : May occur status post anterior cruciate ligament reconstruction.


• David Letterman sign : :Sign of scapholunate ligament disruption (also see Terry Thomas sign).


• Dense vessel sign : Sign of cerebrovascular accident that represent thrombus in the middle cerebral artery.


• Dependent viscera sign : Sign of diaphragmatic rupture (viscera falls to a dependent position).


• Dot and dash pattern : Sacral insufficiency fracture.


• Double bleb sign : Appearance of amnion and yolk sac at 5-6 weeks. Embryo lies between amnion and yolk sac


• Double bubble sign : Sign of duodenal atresia and other forms of duodenal obstruction.


• Double decidua sign : Sign of early normal intrauterine gestation.


• Double density sign (cardiac) : Sign of left atrial enlargement when right side of the left atrium pushes into the adjacent lung.


• Double density sign (Nucs) : Pattern of uptake that may be seen on bone scans in patients with osteoid osteomas.


• Double duct sign : Simultaneous dilatation of the common bile and pancreatic ducts that is generally caused by a tumor in the pancreatic head.


• Double PCL sign : MRI sign of a bucket-handle meniscal tear.


• Double track sign : :Appearance of hypertrophic pyloric stenosis that may be seen on upper GI series.


• Draped aorta sign : Sign of contained rupture of an abdominal aoric aneurysm.


• Drooping lily sign : Inferolateral displacement of the opacified lower pole moiety in a duplex kidney from an obstructed (unopacified) upper pole moeity.


• Egg on a string : Appearance of the heart that may be seen with transposition of great arteries.


• Empty delta sign : Sign of intracranial dural sinus thrombosis.


• Epicardial fat pad sign : Sign of a pericardial effusion.


• Eye of the tiger sign : low signal intensity circumscribing the globus pallidus in patients with Hallervorden-Spatz syndrome.


• Faceless kidney : Appearance of kidney secondary to any process that obliterates renal sinus (i.e. lymphoma, transitional cell carcinoma).


• Fallen fragment sign : Sign of a pathologic fracture seen with unicameral bone cysts.


• Feeding vessel sign : Sign of pulmonary septic emboli.


• Flame shaped (Breast) : Gynecomastia.


• Flame shaped (MSK) : Paget disease.


• Fat halo sign : Seen in various diseases of the bowel in which fatty infiltration of the submucosa is present.


• Fat ring sign : Preservation of the perivascular fat around the mesenteric vessels that may be seen with mesenteric panniculitis.


• Flat tire sign : Sign of a ruptured globe.


• Flat waist sign : Appearance of left heart border that may be seen with left lower lobe atelectasis.


• Figure 3 sign : Appearance of the aorta that may be seen in patients with coarctation of the aorta.


• Figure of eight : Appearance of the brain in pachygyria.


• Finger in glove sign : Sign of mucous plugging seen with allergic bronchopulmonary aspergillosis.


• Fish vertebrae : Description of shape of vertebral bodies that may be seen in patients with sickle cell disease. See also: H-shaped vertebral bodies.


• Football sign : Sign of pneumoperitoneum seen on supine radiographs.


• Gastrointestinal string sign : Sign of Crohn disease.


• Goblet sign : Sign of ureteral transitional cell carcinoma that may be seen on retrograde or intravenous urography (see also Bergman’s coiled catheter sign).


• Gull wing appearance : Appearance of erosions that may occur in patients with erosive osteoarthritis.


• H-shaped vertebral bodies : Shape of vertebral bodies that may be seen in patients with sickle cell disease. See also: Fish vertebrae.


• Halo sign : Ground-glass attenuation surrounding a pulmonary nodule or mass on CT images. Represents hemorrhage and is highly suggestive of Aspergillus.


• Hampton’s hump : Triangular opacity secondary to infarction in the periphery of the lung distal to a pulmonary embolism.


• Head cheese sign : Sign of subacute hypersensitivity pneumonitis.


• Hidebound sign : On small bowel series, crowding of folds in dilated loops of small bowel may be seen in patients with scleroderma.


• High-attenuating crescent sign : Sign of impending abdominal aoric aneurysm rupture.


• Hole within a hole : Appearance that may be seen when eosinophilic granuloma involves the skull.


• Holly leaf appearance : Chest radiograph finding that may be seen with asbestos pleural plaques.


• Honda sign : Sacral insufficiency fracture.


• Hot cross bun sign : May be seen on axial T2 weighted images of the pons in multiple system atrophy.


• Hot nose sign : Sign that may be observed on brain flow scans in patients with brain death.


• Hourglass appearance : MRI appearance that may be seen with concentric cystic adventitial disease.


• Interstitial line sign : Sign that may be seen with an interstitial ectopic pregnancy.


• Inverted Napoleon’s hat sign : Sign of severe spondylolisthesis at the lumbosacral junction.


• Ivory vertebra sign : Increase in opacity of a vertebral body that retains its size and contours, with no change in the opacity and size of adjacent intervertebral disks.


• Juxtaphrenic peak sign : Tenting of the diaphragm that may be seen with right upper lobe atelectasis.


• Keyhole sign : US appearance that may be seen with posterior urethral valves.


• Lace like : Pattern that may be seen with sarcoid arthropathy.


• Lace-like pattern : Ultrasound appearance of hemorrhagic ovarian cysts.


• Lacunar skull : Appearance of skull that may be seen in infants with Chiari II malformation.


• Lambda sign : On a Gallium-67 citrate scan, uptake in the hilar and paratracheal lymph nodes gives the appearance of a lambda. This is seen in sarcoidosis.


• Lead pipe : Narrowing of colon with loss of haustra that may be seen in patients with ulcerative colitis.


• Linguine sign : MRI sign that may be seen in patients with intracapsular breast implant rupture.


• Lobster claw sign : Sign of papillary necrosis on IVU.


• Lollipop : Appearance of diverticula that may been seen on HSG in patients with adenomyosis.


• Luftsichel sign : “Air cresent”. Sign that may be seen with left upper lobe atelectasis.


• Mark Morton sign : Throckmorton’s sign with a small penis.


• Mercedes Benz sign : Appearance of gas within gallstones.


• Moulage sign : Effaced loop of bowel that may be seen on a small bowel series in sprue.


• Molar tooth sign (GU) : Perivesicular extravasation of contrast on CT cystogram in a patient with extraperitoneal bladder rupture.


• Molar tooth sign (Neuro) : Enlarged and horizontally directed tubular structure on each side of the midline emerging from the midbrain in patients with Joubert syndrome.


• Monod sign : Air surrounding an aspergilloma (Also see air crescent sign).


• Mount Fuji sign : CT sign of tension pneumocephalus.


• Naclerio’s V sign : V shaped lucency that may be seen over the left lower mediastinium in pneumomediastinum.


• Nipple sign : Appearance of hypertrophic pyloric stenosis that may be seen on ultrasound.


• Nubbin sign : Reflux nephropathy involving the lower pole of a duplicated collecting system.


• Nutmeg liver : Pattern of liver enhancement seen with passive congestion.


• Onion ring appearance : US appearance that may be seen with a testicular epidermoid cyst.


• Paintbrush appearance : Linear striations of contrast material opacifing collecting tubules that may be seen with medullary sponge kidney.


• Panda sign : On a Gallium-67 citrate scan, uptake in the lacrimal and salivary glands gives the appearance of a panda. This is suggestive of sarcoidosis.


• Parallel track sign : Pattern of uptake that may be seen on bone scan in patients with hypertrophic osteoarthropathy.


• Pear-shaped bladder : Bladder assumes the shape of a pear when it undergoes extrinsic compression due to excess tissue in the pelvis.


• Pearl necklace sign : MRI sign that may be seen with adenomyomatosis.


• Pencil in cup deformity : Erosion pattern of digits that may be seen in patients with psoriatic arthritis.


• Picture frame vertebral body : Thicken cortex of vertebral bodies that may be seen in patients with Paget disease.


• Picket fence : Appearance of bowel that may be seen on small bowel series with Whipple disease or gastrointestinal amyloidosis.


• Pistol grip deformity : Appearance of the proximal femur that may be seen with cam type femoroacetabular impingement.


• Playboy bunny sign : US sign of the appearance of the confluence of the hepatic veins with the IVC.


• Polka-dot pattern : Appearance of thickening trabeculations seen in intraosseous hemangiomas of the spine. See also Corduroy appearance.


• Porcelain gallbladder : Calcification of the gallbladder wall.


• Putty kidney : Appearance that may be seen with end-stage renal tuberculosis.


• Reversal sign : CT sign of anoxic brain injury where gray matter is lower in attenuation that white matter (the opposite is normal).


• Reversed halo sign : Relatively specific sign of pulmonary nodules in cryptogenic organizing pneumonia.


• Ribbon bowel : Appearance of bowel that may be seen on barium studies in graft versus host disease.


• Ribbon ribs : Appearance of ribs that may be seen with neurofibromatosis 1.


• Rice kernel : CT appearance that may be seen with dacryolithiasis.


• Rigler’s sign : Sign of pneumoperitoneum where both sides of a loop of bowel are outlined by air.


• Rim sign : On cholescintigraphy, increased uptake is seen in the region of the gallbladder fossa. Sign is specific for acute cholecystitis.


• Ring of fire sign : US finding. Hypervascular ring in the adnexa that may be seen with either ectopic pregnancy or corpus luteum.


• Ring sign : CT sign of epiploic appendagitis.


• Rosary sign : CT sign that may be seen with adenomyomatosis.


• Rugger jersey spine sign : Appearance of spine that may be seen with secondary hyperparathyroidism or chronic renal failure


• S sign of Golden : Right upper lobe atelectasis created by a central mass. Should raise the suspicion of a central neoplasm.


• Saber-sheath trachea : Appearance of trachea that may be seen with COPD.


• Saber shin : Appearance of tibia that may be seen with syphilis.


• Sandstorm appearance : Appearance of lungs that may be seen in pulmonary alveolar microlithiasis.


• Salt and pepper pattern : Flow voids seen in glomus tumors.


• Salt and pepper skull : Appearance of skull that may be seen in patients with hyperparathyroidism.


• Sandwich sign : Bulky lymphoma encasing mesenteric vessels.


• Sandwich vertebra : Sclerotic endplates that may be seen with osteopetrosis.


• Sausage digit : Soft tissue swelling of digits in patients with psoriatic arthritis.


• Scimitar sign : MRI appearance that may be seen with eccentric cystic adventitial disease.


• Scottie dog : On oblique radiographs, the posterior elements form the appearance of a Scottie dog. Spondylolysis can have the appearance of a collar around the neck.


• Shepard’s crook deformity : Appearance of proximal femur that may be seen with fibrous dyplasia.


• Shoulder sign : Appearance of hypertrophic pyloric stenosis that may be seen on upper GI series.


• Signet ring sign (Chest) : Sign of bronchiectasis.


• Signet ring sign (GU) : Sign of papillary necrosis on IVU.


• Small heart sign : Sign of tension pneumopericardium.


• Snowman : Appearance of heart that may be seen with supracardiac total anomalous pulmonary venous return.


• Snowstorm pattern (breast) : US pattern for breast implant rupture.


• Snowstorm pattern (Ob/gyn) : US pattern for a molar pregnancy.


• Soft-tissue rim sign : Appearance of a ureteral edema surrounding a calculus. Helps differentiates a calculus from a phlebolith (also see comet sign).


• Spade shape : Shape of tufts that may be seen with acromegaly.


• Spalding sign : Overlapping cranial sutures. Sign of fatal demise on prenatal ultrasound.


• Spider web : Appearnace of collateral vessels that may be seen on hepatic venography in Budd-Chiari syndrome.


• Spinnaker sail sign : Elevation of the thymus by air that may be seen with pneumomediastinum.


• Split pleura sign : CT sign of thoracic empyema.


• Spoke wheel enhancement pattern (GU) : May be seen with oncocytomas


• Spoke wheel enhancement pattern (GI) : May be seen with focal nodular hyperplasia.


• Spokewheel sign (GI) : Pattern of mesentery that may be seen with small bowel volvulus.


• Starry sky : US appearance that may be seen with hepatitis.


• Steeple sign : Appearance of narrowing of the subglottic tracheal lumen that may be seen with croup.


• Stepladder sign : US sign that may be seen in patients with intracapsular breast implant rupture.


• Straight line sign : PET sign of peritoneal carcinomatosis.


• Strawberry skull : Appearance of skull that may be seen on fetal US with Trisomy 18.


• String of beads : Appearnace of multiple stenosis that may be seen in patients with fibromuscular dysplasia.


• String sign : Appearance of hypertrophic pyloric stenosis that may be seen on upper GI series.


• Stripe sign : On a V/Q scan, subpleural activity in a region of decreased pulmonary perfusion. Sign is used to rule out pulmonary embolism.


• Subependymal Calcification : Tuberous Sclerosis


• Superior triangle sign : Sign that may be seen with right lower lobe atelectasis.


• Talar beak : Sign of talocalcaneal tarsal coalition.


• Tau sign : MRI sign of a persistent trigeminal artery.


• Telephone receiver shaped femora : Appearance of femora that can be seen with thanatophoric dysplasia.


• Terry Thomas sign : Sign of scapholunate ligament disruption (also see David Letterman sign).


• Throckmorton’s sign : The penis points to the pathology.


• Thumb sign : Classic lateral radiographic finding for epiglotitis.


• Thumbprinting : Sign of bowel wall thickening seen with entities such as ischemic bowel, diverticulitis, Crohn’s disease, and ulcerative colitis.


• Tip of the iceberg sign : Ultrasound sign that may be seen with mature cystic teratomas.


• Tit sign : Appearance of hypertrophic pyloric stenosis that may be seen on upper GI series.


• Tram-track sign (chest) : Sign of bronchiectasis.


• Tram line calcification (neuro) : Sign of optic nerve meningioma in tuberous sclerosis.


• Tram-track calcification (neuro) : Appearance of cortical calcifications that may be seen with Sturge Weber syndrome.


• Tram-track sign (nucs) : Bone scan finding that may be seen with hypertrophic osteoarthropathy.


• Tree in bud : Nonspecific pulmonary pattern seen on thin-section computed tomography,most commonaly with tuberculosis.


• Trident hand : Appearance of hands that may be seen with achondroplasia.


• Trough line sign : In posterior shoulder dislocation, frontal radiographs reveal two nearly parallel lines in the superomedial aspect of the humeral head.


• Umbrella sign : Sign of a ruptured globe.


• Wall-echo-shadow sign : Sign of cholelithiasis on US when the gallbladder is filled with calculi.


• Waterlily sign : Sign of hydatid cyst.


• Water can perineum : Sign of fistula formation secondary to periurethral abscess,associated with gonnorhea infection.


• Wave sign : Sign produced by lateral indentation of thymus by adjacent anterior ribs. This sign in seen in the pediatric population and represents a normal thymus.


• Whirlpool Sign : US sign of midgut volvulus in a neonate.


• Wimberger’s ring sign : A circular, opaque radiologic shadow surroundsing epiphyseal centers of ossification in patients with scurvy.


• Wimberger’s sign : Symmetrical lesions seen in the proximal tibial medial metaphysis in patient’s with syphilis.


• Westermark’s sign : Regional pulmonary oligemia secondary to pulmonary embolism.


• Yin-yang sign : Swirling blood flow pattern within a pseudoaneurysm.


• Yo-yo on a string sign : MRI appearance of a Stener lesion (see Gamekeeper thumb)

One Liners

• Coeur en Sabot /Boot shaped heart - Tetralogy of Fallot
• Pear/Money bag/purse - Pericardial Effusion
• Box shaped heart - Ebstein's anomaly
• Egg on side - TGA
• Snowman/figure of 8 - TAPVC
• Scimtar sign - TAPVC.
• Wide Vascular Pedicle- Corrected TOGV
• Sitting Duck shaped Heart- Persistant Truncus Arteriosus
• Flask shaped Heart wth Pulm. Oligemia- Pericardial Effusion
• Snowman/Figure of 8/ Cottage leaf of Bread heart- TAPVC
• Shaggy Heart ( in chest x-ray)- Pertusis
• Figure of 3 (CXR)/Reversed E sign(Ba swallow) - Coarctation of Aorta
• Hilar Dance sign(Fluoroscopy) - ASD
• Lupus pernio–in sarcoid
• lupus vulgaris–tbskin
• lupus profundus–SLE
• Strawberry tongue- Scarlet fever
• schimitar sacrum is pathognomonic of-sacral meninigocele
• moth eaten appearence in v/q scan in bronchiolitis obliterans
• rosenthal fibres in affected brain is characterisitic of-alexanders disease
• Ground glass hepatocytes-Chronic hepatitis
• SLE-Lupus profundus,Butterfly rash ,Carpet track scales
• SARCOIDOSIS-Lupus pernio
• KWASHIORKAR-Flaky paint dermatosis
• GARDNER SYNDROME-Osteomas
• MEN1-Angiofibroma
• TORRE SYNDROME-Sebaceous adenomas
• Craniopharyngioma-Tumor arising from squamous epithelial cell crests of embryonic Rathke's pouch
• skeletal flurosis-poker back ,slump back,dental mottling
• smoke stack pattern ,ink blot pattern on fundus flourescene angiography -CENTRAL SEROUS RETINOPATHY
• frosted glass appearance on agar plate is characterisitic of BACILLUS ANTHRACIS
• Granuloma,Russel and Mikulicz cells-klebsiella rhinoscleromatis.
• Shermans paradox-Fragile X syndrome
• Positive birefringent rhomboid crystals/calcium pyrrophosphate-Pseudogout
• Negative birefringent-Gout
• Quinsy-peritonsillar abscess usually unilateral
• Tumbler holding position-scaphoid fracture cast
• Retinopathy of prematurity also called-Retrolental fibroplasia
• weber's test lateralized to deaf ear in conductive deafness and towards normal ear in sensorineural deafness.
• False negative rinne-unilateral sensorineural deafness
• Platypelloid-Flattened with short AP and wide transverse diameter