Plain Radiographs in Non-Traumatic Abdominal Pain. Plain Radiographs in Non-Traumatic Abdominal Pain

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1 Jake Block, MD Associate Professor Associate Vice-Chairman for Clinical Operations Director, Musculoskeletal and Emergency Radiology Department of Radiology and Radiological Sciences Vanderbilt University Medical Center Plain Radiographs in Non-Traumatic Abdominal Pain In large prospective studies, only 10% of abdominal plain radiographs for this indication had a specific diagnostic abnormality Bowel obstruction 4% Urolithiasis 2% Ileus 2% Abdominal foreign body 1% Gallstones 1% with 68% non specific and 22% normal. 80% of abdominal CT s performed for the same indication had a specific diagnosis: Urolithiasis, Chron's, pancreatitis, PID, AAA, bowel obstruction, diverticulitis, ischemic bowel, appendicitis. Ahn, et al. Radiology 2002;225: Plain Radiographs in Non-Traumatic Abdominal Pain Just in appendicitis... in the past, an average negative laparotomy rate of 20% was considered acceptable. Multiple studies evaluating CT in appendicitis show: Sensitivities % Specificities 83-97% Accuracies of 93-98% Negative laparotomy rate decreased to 4-7%! CT use is associated with decreased time from ED presentation to appendectomy and decreased perforation rate. In female patients, 433 minutes vs. 710 minutes without CT Lowe, et al. Radiology 2001;221: Ein, et al. J Pediatr Surg 2005;40: Rao, et al. J Comput Assist Romogr 1997;21: Trobati, et.al. Acad emerg med. 2003; 10(8):

2 CT in Non-Traumatic Abdominal Pain Physicians level of confidence prior to CT: Very low (<20%) Physicians level of confidence after CT: Low (20-39%) Moderate (40-59%) High (60-79%) Very high (>80%) Total Very low (<20%) Low (20-39%) Moderate (40-59%) High (60-79%) Very high (>80%) Total Rosen, et al. AJR 2000;174: CT in Non-Traumatic Abdominal Pain Treatment planned prior to CT: Surgery Actual treatment after CT Admit for: Interventional Procedure Observation Send Home: With med tx w/o any tx. TOTAL Admit for: Surgery Interventional procedure Observation Send home: With medical treatment Without any treatment N/A: TOTAL Rosen, et al. AJR 2000;174: CT in Non-Traumatic Abdominal Pain Overall: Patient management is changed in approximately 60% of patients after abdominal CT (versus about 4-10% for plain abdominal radiographs). Hospital admissions averted in 24% of patients. More timely surgical intervention in at least 11%. Rules out significant disorders in 26% of patients. Provides alternate diagnosis in 26% of patients. 2

3 CT in Non-Traumatic Abdominal Pain What we are going to discuss (objectives): What a normal CT scan of the abdomen looks like (systematic review vs. disaster check). Appearance of specific diseases: Cholecystitis Pancreatitis Bowel: bowel obstruction, appendicitis, diverticulitis, GI perforation, intestinal ischemia. Urinary: Pyelonephritis & Ureteral Stones Ruptured AAA & abdominal hemorrhage Miscellaneous inflammatory conditions of the abdomen. Pitfalls in diagnosis. Normal CT of the Abdomen Thin gallbladder wall No pericholecystic fluid or stranding Uniform enhancement of the pancreas Normal pancreatic size and margin No peripancreatic inflammation Patent mesenteric vessels CBD < 1cm No free air Similar sized kidneys Symmetric renal enhancement No perinephric stranding or fluid Normal aortic caliber Non-distended loops of bowel No pericolic inflammation Thin bowel wall Small ureters without inflammation Normal terminal ileum No free fluid collections No RLQ inflammation Normal appendix 80 y/o female with n/v X 5 days. Constipation. Pericholecystic fluid RUQ fat stranding Hydropic gallbladder Gallbladder wall thickening and contrast enhancement Acute Cholecystitis 3

4 Acute cholecystitis What to look for: Thickening of the gallbladder wall (>3mm). Increased density and contrast enhancement of wall. Gallbladder distention (hydrops). Pericholecystic inflammation with haziness of fat. Sometimes Pericholecystic fluid collections. Gas within gallbladder wall or lumen. Perforation with irregular wall contour. Visible stones. Pitfalls? Few, really. Malignancy and gas. Acute cholecystitis Gas in lumen of gallbladder Hydropic gallbladder RUQ fat stranding Emphysematous Cholecystitis Acute cholecystitis Abundant pericholecystic fluid Gallbladder wall enhancement Irregular gallbladder wall Perforated Gallbladder 4

5 Acute cholecystitis (pitfalls) Gallbladder wall thickening and contrast enhancement Intra-luminal mass Grand, D. et al. Am. J. Roentgenol. 2004;183: Gallbladder Carcinoma Acute cholecystitis (pitfalls) Stellate intra-luminal gas No signs of inflammation case of the week #124 Nitrogen Gas within Gallstones 70 y/o female with 1 day h/o abdominal pain and SOB. Mid-abdominal fat stranding Enlarged pancreas Splenic vein thrombus Low density regions Contour irregularities Fluid in retroperitoneum Acute Pancreatitis 5

6 Acute pancreatitis What to look for: Glandular enlargement and contour irregularities. Increased density with enhancement or decreased density (necrosis/edema). Stranding in peripancreatic fat. Retroperitoneal fluid. Sometimes Peripancreatic phlegmon or abscess formation. Hemorrhage. Extraglandular fat necrosis. Thrombosis of portal or splenic vein. True pseudocysts. Pitfalls? Acute pancreatitis Mid-abdominal fat stranding Enlarged pancreas Adjacent rounded fluid collection Pancreatic Pseudocyst Acute pancreatitis Enlarged pancreas Mid-abdominal fat stranding Gas within pancreas Necrotizing Pancreatitis 6

7 Acute pancreatitis Mid-abdominal fat stranding Gas and fluid collection within pancreas Low density region Necrotizing Pancreatitis Acute pancreatitis (pitfalls) Peri-pancreatic fluid collection Beaded pancreatic duct No fat stranding Chronic Pancreatitis Acute pancreatitis (pitfalls) Enlarged pancreas Mid-abdominal fat stranding Pancreatic Adenocarcinoma 7

8 58 y/o male with multiple prior surgeries. 2 day h/o abd pain, n/v. Dilated small bowel loops Angular beak configurations Decompressed distal small bowel Enhancing thickened bowel wall Small Bowel Obstruction (Adhesions) Small bowel obstruction What to look for: Definable transition point from dilated to decompressed small bowel. Bowel wall thickening and enhancement. Identification of underlying cause: Inguinal or abdominal wall hernias. Obstructing mass. Intussusception. Angular or beak-like adhesive configurations. Sometimes Signs of strangulation or ischemia. Pneumatosis, portal venous gas. Perforation with pneumoperitoneum. Small bowel obstruction Dilated small bowel loops Decompressed distal small bowel and colon Angular beak configurations Abdominal Wall Herniation 8

9 Small bowel obstruction Bilateral Inguinal Hernias Small bowel obstruction Dilated small bowel loops Decompressed distal small bowel Mass at transition point Small Bowel Adenocarcinoma Small bowel obstruction Dilated small bowel Decompressed distal small bowel Mesenteric fat within bowel target sign Ileo-ileal Intussusception 9

10 Small bowel obstruction Dilated bowel loops Decompressed distal bowel Angular beak configurations Small bowel obstruction (don t forget ) Pneumoperitoneum Pneumatosis Portal venous gas Gas in mesentery Signs of Strangulation and Ischemia 74 y/o male with 18 hours of epigastric pain, nausea and vomiting. RLQ fluid and fat stranding Appendicolith Dilated, fluid-filled, enhancing appendix Blind-ended limb Acute Appendicitis 10

11 Acute appendicitis Most specific finding overall accuracy ~94-98% What to look for: Dilated and fluid-filled appendix >6mm. Appendicoliths. Enhancement and thickening of the appendix wall. >2mm Periappendiceal inflammation and stranding (in patients with adequate intraperitoneal fat). Sometimes Perforation, abscess, sbo. Pitfalls? Numerous! but mostly just finding the damn thing. Many other conditions can lead to RLQ inflammation and abscess. Many are non-surgical. Acute appendicitis (without labels) Acute appendicitis Free appendicolith RLQ fluid and fat stranding Perforated Appendicitis 11

12 Acute appendicitis RLQ fluid and fat stranding Collection with serpiginous enhancing wall Appendicular Abscess Acute appendicitis (identifying normal) Locate ascending colon in right mid-abdomen Find terminal ileum Assure it is not blind-ended Approximately 3cm (4-8 slices) down locate normal appendix Normal Appendix Acute appendicitis (pitfalls) RLQ fluid and fat stranding Tubular enhancing structure RLQ Abscess Tubo-ovarian Abscess 12

13 Acute appendicitis (pitfalls) Bowel wall thickening RLQ fat stranding Non blind-ending loop Terminal Ileitis in Chron s Disease Acute appendicitis (pitfalls) Bowel wall thickening RLQ fat stranding Non blind-ending loop Chron s Disease Acute appendicitis (pitfalls) RLQ fat stranding Colonic wall thickening Pericolic fluid Typhlitis 13

14 46 y/o male with RLQ after eating sonic cheeseburger. Malodorous stools. Pericolic fat stranding Gas bubbles next to colon Nearby diverticula Colonic wall thickening Diverticulitis Diverticulitis What to look for: Colonic wall thickening. Presence of diverticula. Pericolic fat stranding. Gas bubbles next to the colon. Adjacent free fluid. Sometimes True abscess formation. Substantial free air collections. Pitfalls? Malignancy, colitis, misc inflammatory conditions.. Diverticulitis Colonic wall thickening RLQ fluid and fat stranding Gas bubbles next to colon 14

15 Diverticulitis (pitfalls) Colonic wall thickening Pericolic fat stranding Colon Carcinoma Diverticulitis (pitfalls) Colonic wall thickening and enhancement Pericolic fat stranding Long segment of colon involved Ulcerative Colitis Diverticulitis (pitfalls) Pericolic fat stranding Fat bubble next to colon Infarcted Appendage Epiploica Epiploic Appendagitis 15

16 Diverticulitis (pitfalls) Colonic wall thickening Pericolic fat stranding Acute Colitis -- CMV 38 y/o male with right flank pain increasing over 8 hours. Intrarenal stone Hydronephrosis Renal cortical enlargement Perinephric standing Hydroureter Periureteral Stranding Ureteral Stone Ureteral Stones What to look for: Perinephric stranding. Hydronephrosis. Hydroureter. Periureteral stranding. Other stones. The stone! Sometimes Renal cortical enlargement. Pitfalls? Phleboliths #%@#~! Recently passed stones. 16

17 Ureteral Stones (pitfalls) Watch the ureter! Ureterovesicle junction Phleboliths often are: very round hollow inferior and/or posterior to UVJ accompanied by comet tail sign Phlebolith Ureteral Stones (pitfalls) Stones often are: angular solid and dense accompanied by circumferential soft tissue halo Ureteral Stone 42 y/o male with n/v, abd pain for 2 days. Fever to 103º. Hypotension. Renal enlargement Delayed enhancement Perinephric stranding Focal low-density regions Loss of cortico-medullary differentiation Acute Pyelonephritis 17

18 Acute pyelonephritis What to look for: Focal areas of striation or wedge-shaped low density & non-enhancement. Enlargement of the affected kidney. Stranding in the perinephric fat. Sometimes Loss of sharp corticomedullary differentiation. Delayed nephrogram. True abscess. Pitfalls? Acute pyelonephritis Focal low-density regions Renal enlargement Loss of cortico-medullary differentiation Acute pyelonephritis Striated nephrogram 18

19 Acute pyelonephritis Very low-density regions with enhancing rim Renal Abscess Acute pyelonephritis Gas foci within renal parenchyma Emphysematous Pyelonephritis Acute pyelonephritis (pitfalls) Renal enlargement Delayed enhancement Perinephric stranding Focal low-density regions Nat Clin Prac Onc : Renal Cell Carcinoma 19

20 51 y/o male with known endocarditis, now with fever and right flank pain. Loculated low attenuation collections within iliopsoas muscle Asymmetric bulging muscle contour Rim enhancement Iliopsoas Abscess Iliopsoas Muscle Abscess What to look for: Irregular low-attenuation collections within muscle. Bulging, asymmetric muscle contours. Rim enhancement. Sometimes Gas foci. Direct spread of infection from adjacent organ pathology: Colonic Diverticulitis. Appendicitis. Renal Abscess. Infectious Spondylitis ( discitis /osteomyelitis). Infectious Sacroilitis. Pancreatitis. Iliopsoas Muscle Abscess Loculated low attenuation collection Rim enhancement Asymmetric bulging muscle contour 20

21 Iliopsoas Muscle Abscess Loculated low attenuation collection with rim enhancement Adjacent low attenuation lesion in kidney Iliopsoas Abscess and Renal Abscess (hematogenous spread) Pericolic fat stranding Multiple adjacent diverticula Loculated low attenuation fluid collections with gas foci Iliopsoas Muscle Abscess Sigmoid Diverticulitis with Diverticular Abscess and Psoas Abscess 68 y/o male with excruciating abdominal pain. Hypotension. Abnormal vessel contour Retroperitoneal fluid/hematoma Para-aortic stranding AAA with mural thrombus Contrast dissection Draped aorta AAA Rupture 21

22 AAA Rupture/Spontaneous Abdominal Hemorrhage What to look for: Extravasation of contrast material. Intraperitoneal or retroperitoneal fluid/hematoma. Abnormal vessel contour. Dissecting contrast. Para-aortic stranding. Sometimes Focal discontinuity of calcified vessel rim. AAA >5cm, with increase in size of >1cm in past 6 months. High density crescent within mural thrombus. Draped aorta across spine. AAA Rupture/Spontaneous Abdominal Hemorrhage Para-aortic stranding High density crescent Intraperitoneal hematoma Corners of free fluid AAA Rupture/Spontaneous Abdominal Hemorrhage AAA Rupture (with active extravasation of contrast) 22

23 AAA Rupture/Spontaneous Abdominal Hemorrhage Interrupted calcific rim Retroperitoneal hematoma CT of the Abdomen Acute Atraumatic Abdominal Pain Conclusions: Abdominal pain unrelated to trauma is one of the three most common symptoms in ED patients. Many causes of abdominal pain have similar early clinical presentations. Plain radiographs simply lack sensitivity for important disease. Properly interpreted CT effectively categorizes serious pathology: Immediate surgery required. Surgery within a few hours. Surgery sooner rather than later. Surgery ill-advised in acute setting. Avoid scans gone wild scenarios. Consider Cost/benefit considerations. Risk/benefit considerations. 23