Meta-analyses and prospective studies have demonstrated sensitivity and positive predictive value of graded compression US for diverticulitis of >90%. The accuracy is modestly less than that of CT, but especially so in obese patients and in patients with distal sigmoid diverticulitis. US likely has lower specificity than CT and is less likely to identify an alternative diagnosis. Furthermore, US requires a higher level of training for the diagnosis of diverticulitis than does CT. Dirks et al [25] estimate that a minimum of 500 examinations is required for competency. If used as the initial imaging test at the bedside (eg, point of care), US may hypothetically reduce the number of CT scans performed without a negative effect on patient care, with CT used in inconclusive cases or when the US is negative. US also has the benefit of being noninvasive. Variant 3: Left lower quadrant pain. Suspected complication(s) of diverticulitis. Initial imaging. CT Abdomen and Pelvis CT is the most useful examination for patients with suspected complications of colonic diverticulitis because of its reproducibility, superior diagnostic accuracy [16,19], accuracy for alternative diagnoses with a similar presentation [9,16], risk-stratification of patients for operative versus nonoperative treatment [8,30-32], and inpatient versus outpatient triage [33,34]. IV and oral contrast material may improve diagnosis of abscess by distinguishing from adjacent bowel. Unenhanced CT with oral contrast is less accurate than contrast-enhanced CT with oral contrast for the characterization of complications of diverticulitis but is superior to unenhanced CT without oral contrast [32]. Combining unenhanced CT with contrast-enhanced CT (biphasic imaging) is unnecessary and not recommended [23]. CT can predict unfavorable outcomes from acute diverticulitis. Longer segments of involved colon, retroperitoneal abscess, and extraluminal air have been associated with recurrence, failure of medical management, and need for surgery.
Left Lower Quadrant Pain. Meta-analyses and prospective studies have demonstrated sensitivity and positive predictive value of graded compression US for diverticulitis of >90%. The accuracy is modestly less than that of CT, but especially so in obese patients and in patients with distal sigmoid diverticulitis. US likely has lower specificity than CT and is less likely to identify an alternative diagnosis. Furthermore, US requires a higher level of training for the diagnosis of diverticulitis than does CT. Dirks et al [25] estimate that a minimum of 500 examinations is required for competency. If used as the initial imaging test at the bedside (eg, point of care), US may hypothetically reduce the number of CT scans performed without a negative effect on patient care, with CT used in inconclusive cases or when the US is negative. US also has the benefit of being noninvasive. Variant 3: Left lower quadrant pain. Suspected complication(s) of diverticulitis. Initial imaging. CT Abdomen and Pelvis CT is the most useful examination for patients with suspected complications of colonic diverticulitis because of its reproducibility, superior diagnostic accuracy [16,19], accuracy for alternative diagnoses with a similar presentation [9,16], risk-stratification of patients for operative versus nonoperative treatment [8,30-32], and inpatient versus outpatient triage [33,34]. IV and oral contrast material may improve diagnosis of abscess by distinguishing from adjacent bowel. Unenhanced CT with oral contrast is less accurate than contrast-enhanced CT with oral contrast for the characterization of complications of diverticulitis but is superior to unenhanced CT without oral contrast [32]. Combining unenhanced CT with contrast-enhanced CT (biphasic imaging) is unnecessary and not recommended [23]. CT can predict unfavorable outcomes from acute diverticulitis. Longer segments of involved colon, retroperitoneal abscess, and extraluminal air have been associated with recurrence, failure of medical management, and need for surgery.