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AJR Am J Roentgenol. 2009 Jan;192(1):174-9. doi: 10.2214/AJR.07.3330.

Sonography of acute right lower quadrant pain: importance of increased intraabdominal fat echo.

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Department of Radiology, Konkuk University Hospital and Konkuk University School of Medicine, Hwayang-dong, Gwangjin-gu, Seoul, 143-729, Korea.



The purpose of our study was to assess the diagnostic usefulness of increased intraabdominal fat echo during the sonographic evaluation of patients with acute right lower quadrant (RLQ) pain.


A total of 328 consecutive patients (132 male and 196 female; mean age, 28+/-15 [SD] years) with acute RLQ pain prospectively underwent transabdominal sonography by one of three experienced radiologists. The radiologists prospectively graded intraabdominal fat echo using a 3-point scale: 1, normal; 2, slight increase; and 3, marked and diffuse increase. Final diagnoses were made using surgical or pathologic findings or by clinical follow-up. Of the 328 patients, 11 were lost to follow-up and excluded from analysis. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of increased intraabdominal fat echo were calculated for a positive final diagnosis.


Final diagnoses were negative (n=103), acute appendicitis (n=137), right colonic diverticulitis (n=18), mesenteric lymphadenitis (n=13), enteritis (n=26), and others (n=20). Grades of intraabdominal fat echo were grade 1 (n=158), grade 2 (n=35), and grade 3 (n=124). Overall, fat echo grades 2 or 3 were more frequently observed in patients with a positive final diagnosis (73% [157/214] vs 2% [2/103], p<0.001) than in those with a negative final diagnosis. Sensitivity, specificity, accuracy, PPV, and NPV of increased intraabdominal fat echo for a positive final diagnosis were 73%, 98%, 81%, 99%, and 64%. Increased intraabdominal fat echo was documented in 89% (122/137) of cases of acute appendicitis and in 100% (18/18) of cases of right colonic diverticulitis.


An increased intraabdominal fat echo on sonography is highly specific for the presence of RLQ inflammatory disease.

[Indexed for MEDLINE]

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