Classic Radiology Signs

Classic Radiology Signs These classic signs are listed in alphabetical order and can be found listed in various texts. The list here is a compilation from Dr. Smoger, S. Quazi, and from Michael E. Mulligan's Classic Radiologic Signs: An Atlas and History, available through the Department. Images of the listed signs can be found in the text. Apple Core lesion  ²signifies annular carcinomas of the colon²looks like an app le core or  napkin ring(see below) due to circumferential narrowing of the lumen, noted o n contrast studies.

Bamboo Spine ²fused spinal segments with their syndesmophytes look, on radiographs, similar  to bamboo stalks²classically stalks²classically associated with ankylosing ank ylosing spondylitis.

Bird's Beak² noted on Upper GI with contrast, a dilated upper/middle esophagus with an abrupt taper to exceptionally narrowed lumen, typical of achalasia.

Boot-shaped Heart  ²due to RVH, the LV is lifted lifted above abo ve the edge of o f the diaphragm, forming the ³toe´ of o f the boot. Classic for Tetralogy of Fallot.

Bat's Wing/Butterfly  ²this appearance on CXR is classically associated with CHF and resultant pulmonary edema.

stud ies due to ulcerative pockets, Cobblestone appearance²  this sign is produced on barium studies usually in the terminal ileum, indicative of Crohn 's.

Codman's Triangle  ²a triangle on plain p lain film of extremities that signifies reactive bone, classically associated with osteosarcoma, or other infectious/hemorrhagic process that causes  periosteal elevation.

Coin lesion²  solitary solitary pulmonary nodule; may be cancer o r granuloma.

Cookie Cutter lesions²  metastatic lesions to bone cortex, or Paget's. Crescent sign²  classic sign of avascular necrosis, femoral head.

Egg-on-a-string²  a large, ovoid-shaped heart on newborn CXR, classically signifying complete transposition of the great vessels with intact ventricular septum.

Ground glass²  a ³white-out´ on CXR, usually PCP pneumonia or ARDS.

Hampton's Hump²  a peripheral triangle, usually near pleural edges, c lassically PE. Honeycomb lung²  used to describe any pathologic process that causes radiographic appearance of multiple small, thick-walled cystic spaces; e.g. pulmonary fibrosis. Lead pipe sign²  classic narrowing of bowel lumen, with loss of haustra²UC.

Napkin Ring sign²  see Apple core lesion above; pathology identical, but lumen more narrowed. Onion-skinning  ²layered look of periosteum in Ewing's Sarcoma. Rachitic Rosary  ²this is a ³string of beads´ appearance on x-ray, a thickening of costochondral margins that is noted in Ricketts(Vit. D Deficiency). Sail sign  ²fat pad noted on plain film, indicative of shoulder disclocation. Scotty dog(collar)  ²on posterior oblique, the lumbar vertebrae look like a Scottish terrier. The neck is the pars interarticularis, and a break(a co llar) noted there indicates spondylolysis. String sign ²thin, slightly irregular shadow in narrowed lumen of ileum, suggestive o f Crohn's. Silhouette sign  ²obliteration of cardiovascular silhouette due to adjacent disease, ie  pneumonia, TB, etc. Stepladder appearance  ²distended bowel loops, often indicative of obstruction, usually SBO.

Sunburst appearance²³clouds, clumps, and consolidated rays´ of tissue emanating from bone cortex, or within bony structures, indicative of osteosarcoma. Thumb(print) sign  ²on lateral c-spine, an enlarged epiglottis appears as a ³thumb´²  epiglottitis. Westermark's sign  ²abrupt end to a pulmonary vessel, signifying oligemia or PE.

Small Bowel Obstruction

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General considerations Small bowel obstruction, as the term is used here, is due to physical and organic changes o which produce mechanical obstruction to the passage of the bowel contents somewhere in the small bowel o The bowel proximal to the point of obstruction dilates with swallowed air and secreted fluid, Vomiting may release some of the proximal bowel contents and reduce the amount of proximal dilation The bowel hyperperistalses o 

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Bowel distal to the point of obstruction (i.e. colon and sometimes distal small bowel) empties over time Strangulation of the bowel may result from vascular compromise of the affected loops and is a cause of increased mortality

Causes Overwhelmingly, the most common cause of a mechanical small bowel obstruction are o adhesions related to prior surgery (60%) The most common prior surgeries associated with a subsequent SBO include appendectomy, colorectal surgery and gynecologic surgery Bowel may become kinked under an adhesion The obstruction is frequently partial or intermittent o Hernias Most often femoral or inguinal Intussusception o 

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Volvulus Tumor, either primary or metastatic Wall lesions such as leiomyomas or strictures Crohn¶s disease

Foreign bodies o Gallstones Such as in gallstone ileus (which is actually a mechanical obstruction, usually at t he ileocecal valve) Clinical findings Abdominal pain and distension o Most marked in patients with distal SBO although its onset in distal obstructions is later in the course of the d isease than in proximal obstruction Typically colicky in nature and progressively worsening over time o  Nausea Vomiting o An earlier sign of a pro ximal than a distal obstruction Fluid and electrolyte imbalances from vomiting increase mortality Constipation o History of prior abdominal or pelvic surgery o Bowel sounds are hyperactive and high-pitched o Absence of bowel sounds may indicate bowel ischemia or peritonitis o

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Imaging o

findings Conventional radiography is the study of first choice Loops proximal to the po int of obstruction will become dilated and fluid-filled

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Usually greater than 2.5-3 cm in size Differential height of air-fluid levels in the same loop o f small bowel no longer  considered reliable sign of mechanical SBO Absence of, or disproportionately smaller amount of, gas in the colon, especially the rectosigmoid Loops of small bowel may arrange t hemselves in a step-ladder  configuration from the left upper to the r ight lower quadrant in a distal SBO Mostly fluid-filled loops of bowel may demonstrate a string-of-beads sign caused by the small amount of visible air in those loops y

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Bowel Obstruction. Supine view of the abdomen (left) shows several dilated loops of small  bowel  in the upper abdomen. The small bowel is disproportionately dilated compared the the large bowel  which is collapsed. The upright view (right) demonstrates multiple air-fluid levels in the dilated  loops in a typical configuration of a small bowel obstruction. The patient had previous bowel surgery. For a larger photo of the same image, click here

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CT may demonstrate the site and cause of the obstruction Dilated and fluid-filled loops of small bowel prox imal to the obstruction and collapsed loops of small bowel and/or colon distal to the obstruction  Small bowel feces sign is seen in SBO because of the intermixing of air with material that is static in obstructed small bowel, resembling the appeara nce of feces While adhesions are not imaged per se, their presence can be inferred by a rapid change in bowel caliber without any other causes of obstruction (e.g. tumor) suggested Signs of strangulation include thickening of the bowel wall, increased attenuation of  the bowel wall, stranding of the adjacent small bowel mesentery or pneumatosis intestinalis CT may demonstrate tumors, Crohn¶s disease, gallstone ileus, hernias, closed loop obstructions which are usually not diagnosable o n conventional radiographs

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CT of Small Bowel Obstruction .  Axial CT scan through the lower abdomen shows multiple fluid-filled and dilated loops of small bowel (white arrows) and collapsed  right colon (red arrow) consistent with a mechanical small bowel obstruction.

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Closed-loop obstructions o Most (75%) are caused by adhesions

In a closed-loop obstruction, the twisted loop itself remains dilated with gas and fluid thus producing a dilated, U-shaped loop of small bowel Does not change in position or size over time C offee bean sign or  pseudotumor may be seen o Closed-loop obstructions are not usually diagnosable by conventional radiography and require CT CT findings may include a U- or C-shaped loop of small bowel A spoke-like configuration of the mesentery demonstrating stretched vessels converging on the site of the twist may be seen The appearance of the tightly twisted mesentery has been called the whirl sign The beak sign may be seen as a fusiform tapering at the site of the obstruction Treatment of small bowel obstruction o

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Many patients are treated conservatively with small bowel decompression and intravenous fluids Surgical intervention may be necessary if there are signs and symptoms of strangulation,  peritonitis or lack of response to conservative treatment

Differentiating

SBO from Paralytic Ileus SBO

Ileus

Etiology

Patient with prior surgery weeks to years prior 

Recent (hours) post-operative  patient

Pain

Colicky

Not a prominent feature

Abdominal distension

Frequently prominent

Sometimes not apparent

Bowel sounds

Usually increased

Usually absent

Small bowel dilatation

Present

Present

Large bowel dilatation

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Present

Renal Path -Type II Rapidly Progressive (cresentic) GN associated with SLE and Henoch-Schlura  purpura Type III - Wegner's granulamoutousisisis(sp?) and microscopic polyangitis -IgA nephropathy (berger's

Disease)

- assocaited with Celiac Disease; intermittent hematuria

-Alports syndrome - XD, can be AD or AR; foamy change in tubular epithelial cells, -Nephrotic Syndrome --» see Oval Fat bodies which are sloughed tubular cells containing abundant lipid

-membranous GN - granular deposits are of IgG and C3 -minimal change disease - fusion of foot procesess are due to injury induced by T-ce ll derived cytokines -RCC --» see painless hematuria in an adult, think neoplasm. --» usually unilateral, doesn't destory all of kindney, no sig loss of  renal fxn, HTN due to Inc. renin secretion. 1) Clear Cell Ca --» MC, presents with painless hematuria in 6th or 7th decades. 80% show sporadic loss of VHL gene --» germ line mutation of VHL loss occurs in 4th decade of life, assoc w/ von Hippel Lindua syndrome (which is associ with other tumors)

2) Papillary variant of RCC --» MET o n chr7 -Hemolytic-Uremic Syndrome (HUS) 1)MCC of acute renal failure in children, occurs after ingestion of meat infected with E.COli o157:h7 2) may see microangiopathic hemolytic anemia

-Adult Polycystic Kidney Disease (APK D) MC C/x are HTN and infection, Inc. risk of RCC, AD (= adu lt onset of the dz), cysts are 1-4cm, replace kidney, can see cysts in liver and pancreas as well, assoc with berry aneurysm, non-smoot h kidney surface -Juvenille Polycystic Kidney Disease (JKPD) AR, occurs in neonates or prenatal, cysts involve liver, kidneys have smooth surface.

-Hypercalcicuira doesn't have to be linked to Hypercalcemia, T/x = thiazide diuretics -Acute drug-induced intersititial nephritis 1) caused by ampicillin (PCN?), see eosinophils in urine -ATN due to ischemia 1) accompanied by rupture of basement membrane (tubulorrhexis?) 2) 3 phases; (a) initiating phase, lasts 1 day (b) maintenance phase  progrossive oliguria and increasing BUN levels with salt and h20 overload (c) recovery phase - inc. urinary output and hypokalemia then restoration of of tubular fxn. -Renal Papillary Necrosis 4. Analgesic nephopathy - chr usage of acetaminophen and aspirin

-Simple cysts common in adults, may be multiple, but not as numerous as those in APKD, no renal failure, may become as large as 10cm, can hemorrhage into cyst -Chronic Pyelonephritis due to reflux nephropathy 1)coarse and irregular scarring from asc. infxn. 2)blunting and deformity of the calyces

-Prerenal Azotemia = basically due to Dec. C.O. ==» Dec. RBF, etc[/b]