SIGNIFICANCE OF EXTRALUMINAL ABDOMINAL GAS: LOOKING FOR AIR IN ALL THE WRONG PLACES Richard M. Gore, MD North Shore University Health System University of Chicago Evanston, IL SCBT/MR 2012 October 26, 2011 3:00-3:10
NO DISCLOSURES rgore@uchicago.edu
TOPICS PNEUMOPERITONEUM PNEUMORETROPERITONEUM PNEUMATOSIS INTESTINALIS PORTAL-MESENTERIC VENOUS GAS PNEUMOBILIA
PNEUMOPERITONEUM
THE SPECTRUM OF PNEUMOPERITONEUM Expected and benign finding requiring no treatment Sensitive indicator of sudden and lifethreatening perforation of the GI tract
PNEUMOPERITONEUM: BENIGN CAUSES Surgery Surgery Percutaneous Endoscopic Gastrostomy Percutaneous Peritoneal dialysis Endoscopic Gastrostomy Peritoneal Biopsy dialysis Biopsy Percutaneous abscess drainage Percutaneous Pneumothorax abscess drainage Pneumomediastinum
PNEUMOPERITONEUM: LIFE-THREATENING Perforation of benign ulcer Diverticulitis Appendicitis Perforation of neoplasm Pneumatosis Bowel obstruction
PNEUMOPERITONEUM: LIFE-THREATENING Intestinal ischemia and infarction Toxic megacolon Necrotizing enterocolitis Inflammatory bowel disease Typhlitis Pseudomembranous colitis
PNEUMOPERITONEUM: LIFE-THREATENING Anastomotic leak Upper GI endoscopy Colonoscopy
RIGLER S SIGN
LIVER EDGE SIGN
FALCIFORM LIGAMENT SIGN
BENIGN CAUSES OF PNEUMOPERITONEUM
POSTOPERATIVE PERITONEAL DIALYSIS PERCUTANEOUS GASTROSTOMY
POSTOPERATIVE PNEUMOPERITONEUM POSTOPERATIVE PNEUMOPERITONEUM
POSTOPERATIVE (OPEN) PNEUMOPERITONEUM ON UPRIGHT CXR POD # 5 28.4% POD # 6 20.0% POD # 7 11.0% Tang Dis Colon Rectum 43: 1116-1120, 2000
FACTORS INFLUENCING DURATION OF POST OPERATIVE PNEUMOPERITONEUM Obesity: prevalence of PP is less in fat compared to thin patients Gender: PP more prevalent in men Drains: greater incidence of PP No effect: age, surgery duration, presence and location of anastomosis, time to flatus, time to first bowel movement
PP IN THE ERA OF LAPAROSCOPIC SURGERY Iatrogenic GI tract perforations due to trocar insertion and thermal injury: 0.06%- 0.4% Artificial pneumoperitoneum Small incisions minimize room air
PP IN THE ERA OF LAPAROSCOPIC SURGERY Iatrogenic GI tract perforations due to trocar insertion and thermal injury: 0.06%- 0.4% Artificial pneumoperitoneum Small incisions minimize room air
PP IN OPEN vs LAPAROSCOPIC CHOLECYSTECTOMY ON CXR-24 hrs Open cholecystectomy: 60%, minimal to moderate 2:1 Laparoscopic cholecystectomy: 24%, minimal to moderate 5:1 Gayer Semin Ultrasound, CT, MR 25: 1286-289, 2004
PP: CT vs RADIOGRAPH 3 days postoperative: 87% on CT, 53% on plain radiograph 6 days postoperative: 50% on CT, 8% on plain radiograph Earls AJR 161: 781-785, 1993
IN PATIENTS WITH COMPLICATIONS The amount of free air should be decreasing Any increase is very worrisome Difficult to exactly compare quantity of gas on CT study with radiograph
PERITONEAL DIALYSIS
PERITONEAL DIALYSIS Seen in 30% of patients on PD The presence, quantity, and distribution of free air is not helpful in separating perforations from nonperforations Lee JCAT 18: 439-442, 1994
PERCUTANEOUS ENDOSCOPIC GASTROSTOMY
PNEUMOPERITONEUM S/P PEG TUBE INSERTIONS 8.6%-55.6% Free air on CXR 1 to 3 days Free air on CT 1 to 9 days In the absence of clinical symptoms is of no clinical significance and does not need further evaluation
LIFE- THREATENING CAUSES OF PNEUMOPERITONEUM
GI TRACT PERFORATION
PERFORATION Emergent condition that requires prompt surgery Spontaneous, traumatic, or iatrogenic causes Variable clinical presentations, particularly in the early clinical course
GI TRACT PERFORATION Concentration of air bubbles next to gut Supramesocolic vs inframesocolic space Preponderance of abdominal vs pelvic gas Perivisceral fat stranding Segmental bowel wall thickening Abscess Extraluminal fluid Focal defect in bowel wall
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Extraluminal contrast Focal defect in bowel wall Segmental bowel wall thickening Abscess-fluid
GI TRACT PERFORATION Concentration of air bubbles next to gut Supramesocolic vs inframesocolic space Preponderance of abdominal vs pelvic gas Perivisceral fat stranding
GI TRACT PERFORATION Concentration of air bubbles next to gut Supramesocolic vs inframesocolic space Preponderance of abdominal vs pelvic gas Perivisceral fat stranding
GI TRACT PERFORATION Concentration of air bubbles next to gut Supramesocolic vs inframesocolic space Preponderance of abdominal vs pelvic gas Perivisceral fat stranding
GI TRACT PERFORATION Concentration of air bubbles next to gut Supramesocolic vs inframesocolic space Preponderance of abdominal vs pelvic gas Perivisceral fat stranding
GI TRACT PERFORATION Concentration of air bubbles next to gut Supramesocolic vs inframesocolic space Preponderance of abdominal vs pelvic gas Perivisceral fat stranding
FISSURE LIGAMENTUM VENOSUM- FALCIFORM LIGAMENT
CT FEATURES OF PNEUMOPERITONEUM PROXIMAL GI PERFORATION FALCIFORM LIG 60% 0% DISTAL GI POCKETS OF AIR 10% 69% WALL THICKENING 50% 100% ABSCESS 20% 53% ASCITES 90% 63% FAT STRANDING 30% 72% Yeung J Clin Imaging 28: 329-333, 2004 PERFORATION
GI TRACT PERFORATION: LOCATION OF GAS BUBBLES IN 86 PATIENTS Stomach and liver Inframesocolic Infra- and supramesocolic Gastroduodenal perforation 29 0 8 Small bowel perforation Colon perforation 1 2 6 0 15 24 Hainaux AJR 187: 1179-1183, 2006
CT FEATURES OF PNEUMOPERITONEUM (n=53) UPPER GI PERFORATION LOWER GI PERFORATION PERIPORTAL FREE AIR FALCIFORM LIGAMENT LIGAMENTUM TERES 93 35 80 43 53 8 Cho HS Eur J Radiology 2007
GASTRODUODENAL PERFORATIONS Peptic ulcer disease Necrotic or ulcerated malignancies Large amount of extraluminal air Air in lesser sac, ligamentum teres, ligamentum venosum Ulceration, focal interruption of wall, abrupt wall thickening with adjacent increased fat density
GASTRODUODENAL PERFORATIONS Traumatic injures involve 2 nd and 3 rd portions of the duodenum Blunt trauma in children and penetrating trauma in adults Cause pneumoretroperitoneum in the anterior pararenal space
GASTRODUODENAL PERFORATIONS DUODENAL 38.3% JUXTA-PYLORIC 35.6% GASTRIC 19.1% PYLORIC 6.8% Grassi Eur J Radiology 50: 30-36, 2004
PEPTIC ULCER DISEASE
DIVERTICULITIS
PERFORATED NSAID ULCER
PERFORATED ANTRAL ULCER
PEPTIC ULCER DISEASE
SUPERIOR RECESS LESSER SAC
SMALL BOWEL PERFORATIONS Diverticulitis Ischemic or bacterial enteritis Crohn s disease Ingested foreign bodies Bowel obstruction Volvulus Intussusception
SMALL BOWEL PERFORATIONS Abdominal trauma Iatrogenic injury Postoperative perforation Anastomotic leakage Amount of extraluminal air is small or absent in most cases unlike UGI perf Extraluminal air seen in only 50% of CTs
SMALL BOWEL PERFORATIONS Findings often subtle- search for gas trapped in mesenteric folds Postoperative perforation and anastomotic leakage usually occur within first week of surgery Suggest perforation or leak with persistent or progressively increasing free air
PERFORATED ILEUM BY CHICKEN BONE
PERFORATED ILEUM BY CHICKEN BONE
SMALL BOWEL PERFORATION
COLONIC PERFORATION Malignant neoplasm Diverticulitis Spontaneous perforation Trauma Ischemia
COLONIC PERFORATION Free air on plain radiograph 33% Free air on MDCT 100% Dirty fat sign 100% Wall thickening at perf site 100% Extraluminal fluid 100% Dirty mass 83% Interruption of colon wall 67% Miki JCAT 31: 169-176, 2007
COLONIC PERFORATION: LEFT SIDED Malignant neoplasm Diverticulitis Spontaneous perforation Blunt trauma Ischemia
COLONIC PERFORATION: RIGHT SIDED Inflammatory lesions Penetrating trauma Cecum- LBO, toxic megacolon, ileus
DIVERTICULITIS
DIVERTICULITIS
ANASTOMOTIC LEAKS Leak rate 3.6% to 9% 30% may have clinically occult leaks High risk: low rectal anastomosis and Whipple s procedure
ANASTOMOTIC LEAKS Peri-anastomic fluid and gas are the best indicators of anastomotic leaks
A A A
PNEUMORETROPERITONEUM
PNEUMORETROPERITONEUM Postoperative Postdiagnostic procedure (ERCP) Penetrating trauma Blunt traumatic rupture of duodenum Pelvic trauma with rectal perforation
PNEUMORETROPERITONEUM Spontaneous colonic perforation volvulus, obstruction, carcinoma, diverticulitis Extension from pneumomediastinum Gas-containing retroperitoneal abscess
PERFORATION DURING ERCP
PERFORATION FROM COLONOSCOPY
OCCULT COLONIC PERFORATION WITH INCOMPLETE COLONOSCOPY Optical colonoscopy perforation rate is 1/3,115 (.032%) to 1/510 (0.196%) 2/262 (0.8%) had occult perforation Recommend low dose CT before rectal tube insertion and gas insufflation in all patients with same day or next day CTC Hough AJR 191: 1077-1081, 2008
ACCURACY OF MDCT IN DETECTING PERFORATION SITE OF GI TRACT Axial images only: 87.8% Axial + MPR images: 93.9% Kim JW Abdominal Imaging 36: 503-508, 2011 (Oct)