Upload
doctmacc
View
54
Download
4
Embed Size (px)
Citation preview
Seeing the signs of Radiology
Trevor Downing, MSIV
To quote Dr. Neuffer
• “These are the things Radiologists come up with when they sit in the dark too long…”
• Or something like that
Classic signs
Apple core sign
• Must r/o adenocarcinoma of colon • DDx:
– Malignant neoplasms (adenocarcinoma, lymphoma)– Benign neoplasms (villous adenoma)– IBD (chronic Crohn’s or UC)– Vascular disorders (ischemic colitis)– Infections (tuberculosis, helminthoma, ameboma)
• Studies of double-contrast barium enema as screening for colorectal cancer– Detects only ~1/2 of adenomas >1cm and 39% of all polyps.
May miss 15-22% of colorectal cancers– Use decreasing due to more accurate colonoscopy or CT
colonography
Bamboo spine
• Ankylosing spondylitis– Chronic inflammatory disease of the axial skeleton causing
back pain and progressive stiffness of spine– Peak age of onset 20-30yrs– Ankylosis refers to fibrous or bony bridging of joints– Part of the spondyloarthritis disorders – inflammation of the
entheses (insertion sites of ligaments on bones). – Dx:
• Clinical findings (inflammatory back pain, ↓ROM of back) • Lab testing – HLA-B27• Imaging
Bamboo spine
• Imaging– Abnormal SI joint on plain AP pelvic radiographs
seen in longstanding disease. • Findings: joint widening, erosions, sclerosis or ankylosis
– If no findings but suspicion is high then follow with MRI of pelvis.
– If MRI contraindicated then CT scan can detect erosions, bony sclerosis but not acute inflammatory changes
Champagne sign• Emphysematous cholecystitis
– US image reveals multiple tiny echogenic reflectors within the gallbladder lumen (arrows) corresponding to gas bubbles leaving from dependent wall.
– Often a complication of acute cholecystitis, caused by gas forming bacteria (mostly C. perfringens, Ecoli, gut bacteria)
– More common in men, elderly (>60yrs) and diabetics.
Champagne sign
• Emphysematous cholecystitis– Imaging
• Plain films may show air in wall/lumen• CT scan:
– GB wall thickening >3mm– Cholelithiasis– Increased bile density (>20H)– Loss of clear GB wall definition– Pericholecystic fluid (halo)
– Treatment• Percutaneous preoperative drainage + antibiotics
• Open cholecystectomy – laparoscopic less successful
Bat’s wings or butterfly appearance
• Congestive heart failure (HF)– Chest x-ray is often first diagnostic test
• Differentiates between HF and 1H pulmonary disease (dyspnea)
– Bat’s wings are bilateral perihilar edema– Findings suggestive of HF
• Cardiomegaly – cardiac:thoracic width >50%• Cephalization of pulmonary vessels• Kerley B-lines – pulmonary edema in interlobular septa• Pleural effusions
– Study of 880 patients showed• Cephalization, alveolar edema or interstitial edema all had >90%
specificity for HF• Cardiomegaly had only 50% sensitivity
Codman’s triangle• Osteosarcoma
– 1H malignant tumor of bone – malignant cells make osteoid or immature bone
– Uncommon tumor but #1 primary malignancy of bone in children and adolescents
• Bimodal distribution - <20yrs and >65yrs
– Most common sites• Children: metaphyses of long bones (distal femur 75%,
proximal tibia, proximal humerus)
• Adults: axial skeleton
Codman’s triangle• Osteosarcoma
– Risks• Prior irradiation/chemotherapy
• Paget’s disease – usually osteosarcoma in pts >40yrs
• Chronic osteomyelitis
• Multiple hereditary exostoses
• Fibrous dysplasia
• Metallic implants
• Hereditary retinoblastoma
• Li-Fraumeni syndrome (p53 mutation)
Codman’s triangle• Dx:
– First diagnostic test usually plain radiograph• Codman’s triangle new periosteal bone formation lifting
the cortex. • The associated sunburst appearance soft tissue
ossification.
– No bone findings are pathognomonic – biopsy needed
– DDx: • Malignant bone tumors (Ewing’s, lymphoma, mets)• Benign bone tumors (osteoid osteoma,
chrondroblastoma, osteochrondroma)• Non-neoplastic (osteomyelitis, eosinophilic granuloma,
bone cysts)
Hampton’s hump & Westermark’s sign
• Pulmonary embolus– Hampton’s hump
• Pleural based, wedge shaped consolidation represents area of infarction and atelectasis
– Westermark’s sign• Area of decreased density lateral to PE
represents oligemia distal to PE as well as distended/engorged pulmonary vessels.
Hampton’s hump & Westermark’s sign
• Pulmonary embolus– Radiographic abnormalities common in PE but not helpful
diagnostically
Strange signs
Anteater nose sign• Calcaneonavicular tarsal
coalition– Tarsal coalition abnormal
union or 2 or more tarsal bones– 2 most common types
• Calcaneonavicular• Talocalcaneal
– Causes are congenital or acquired
• Acquired: trauma, infection, surgery, articular disorders
Anteater nose sign
• Initial evaluation of tarsal coalition – conventional radiography– Oblique, AP and lateral weight bearing views
of feet– CT/MRI for complicated cases or preoperative
planning– MRI is useful for nonosseous fibrous or
cartilaginous coalitions
David Letterman sign(Aka Terry Thomas)
• Scapholunate dissociation (dislocation)– Most common and significant wrist ligament injury– Mechanism of injury:
• Similar to scaphoid fx – falling on outstretched hand (carpal loading)• Common in contact sports due to jamming extended hand into other
athletes
– Imaging• AP radiograph scapholunate distance >3mm & flexed scaphoid.• Lateral view increased scapholunate angle• MRI helpful
– In children: difficult to interpret due to incomplete ossification
– Incomplete tear of ligament
Mount Fuji sign• Tension pneumocephalus
– Causes• Iatrogenic: most commonly after neurosurgical evacuation
of subdural hematoma (2.5-16% incidence).– Other: skull base surgery, paranasal sinus surgery
• Non-iatrogenic: head trauma, nitrous oxide anesthetic, scuba diving?
– Mount Fuji sign useful test to distinguish tension from non-tension pneumocephalus
• Emergency surgery vs non-operative• Ishiwata study showed Mount Fuji sign positive in 4/5
patients with surgically confirmed tension pneumocephalus, not seen in any non-tension cases.
Yin-yang sign
• True and false aneurysm– Yin-yang sign due to partial thrombosis of aneurysm.
Contrast enhanced CT delineates lumen with active blood flow from the thrombosed portion
• Utility– Two studies showed 82 & 89% of aneurysms demonstrated
presence of mural thrombus.– This finding particularly helpful in 2 regions of body where
hard to differentiate from ddx• Brain: suprasellar meningiomas, craniopharyngiomas, hemorrhagic
metastases• Abdomen: cystic pancreatic tumors, islet cell tumors, solid/epithelial
neoplasms, pseudocysts, gastric leiomyomas and leiomyosarcomas– However, not a specific sign for aneurysms
• Rare solid or papillary neoplasms may show sign.
Throckmorton sign(John Thomas sign)
• Penis points towards the side of pathology– “The sign tends to be commented on by middle-
aged male radiologists and orthopedists suffering from Peter pan syndrome.”
• 2 studies– Medical Journal of Australia 1998 sensitivity
70%, specificity 67%– UK study sensitivity 30%, specificity 86%
• Mark Morton sign is a “smaller” Throckmorton
References• Winawer, SJ, Stewart, ET, Zauber, AG, et al. A comparison of colonoscopy and double-contract barium
enema for surveillance after polypectomy. National Polyp Study Work Group. N Engl J Med 2000; 342:1766.
• Toma, J, Paszat, LF, Gunraj, N, Rabeneck, L. Rates of new or missed colorectal cancer after barium enema and their risk factors: a population-based study. Am J Gastroenterol 2008; 103:3142.
• Klauser, A, Bollow, M, Calin, A, et al. Workshop report: clinical diagnosis and imaging of sacroiliitis, Innsbruck, Austria, october 9, 2003. J Rheumatol 2004; 31:2041.
• Knudsen, CW, Omland, T, Clopton, P, et al. Diagnostic value of B-Type natriuretic peptide and chest radiographic findings in patients with acute dyspnea. Am J Med 2004; 116:363.
• Le Vu, B, de Vathaire, F, Shamsaldin, A, et al. Radiation dose, chemotherapy and risk of osteosarcoma after solid tumors during childhood. Int J Cancer 1998; 77:370.
• Grimer, RJ, Cannon, SR, Taminiau, AM, et al. Osteosarcoma over the age of forty. Eur J Cancer 2003; 39:157.
• Papagelopoulos, PJ, Galanis, EC, Vlastou, C, et al. Current concepts in the evaluation and treatment of osteosarcoma. Orthopedics 2000; 23:858.
• Blakemore LC, Cooperman DR, Thompson GH. The rigid flatfoot. Tarsal coalitions. The rigid flatfoot. Tarsal coalitions. Clin Podiatr Med Surg. Jul 2000;17(3):531-55. [Medline].
• Crim JR, Kjeldsberg KM. Radiographic diagnosis of tarsal coalition. AJR Am J Roentgenol. Feb 2004;182(2):323-8. [Medline].
• Waters, PM. The upper limb. In: Lovell and Winter's Pediatric Orthopaedics, 6th ed, Morrissy, RT, Weinstein, SL (Eds), Lippincott Williams & Wilkins, Philadelphia 2006. p. 921.
• Steven J. Michel, The Mount Fuji Sign. Radiology August 2004 232:44945010.1148/radiol.2322021556 • Ishiwata Y, Fujitsu K, Sekino T, et al. Subdural tension pneumocephalus following surgery for chronic
subdural hematoma. J neurosurgery 1988; 68:58-61• Tommaso Lupattelli, The Yin-Yang Sign. Radiology March 2006 238:1070107110.1148/radiol.2383031884