Acute Pyelonephritis diagnosis of acute extrarenal conditions including cholecystitis (n = 1), liver abscess (n = 1), and appendicitis (n =1), which were all subsequently diagnosed with contrast-enhanced CT [19]. In the absence of a history of renal stones, the benefit of performing unenhanced CT in combination with contrast- enhanced CT is negligible in a complicated patient with suspected APN. In a small retrospective study of adult patients with clinical and laboratory suspicion of APN who all underwent triphasic abdominal CT (n = 100), the accuracy of the nephrographic phase among 2 readers for diagnosis of APN was 90% to 92% and for diagnosis of urolithiasis was 96% to 99% [22]. There was no significant difference in the accuracy of the triphasic abdominal CT relative to the nephrographic phase only [22]. In a prospective nonrandomized data collection study of patients with a final diagnosis of APN (n = 827), the detection rate of APN was 84.4% (445/527) by abdominal CT and only 40% (72/180) by abdominal US [10]. Although the detection rate of urolithiasis and hydronephrosis were similar by abdominal CT and abdominal US, the rate of detection of renal abscess was 4.0% (21/527) by abdominal CT and only 1.1% (2/180) by US [10]. US, CT, and MRI can show evidence of chronic pyelonephritis, including renal scarring, atrophy and cortical thinning, hypertrophy of residual normal tissue, and renal asymmetry [1,8,14,15,17,19,20]. Advantages of abdominal CT and US over abdominal MRI may include superior detection of urolithiasis, and CT may be superior to US and MRI in detection of gas in emphysematous pyelonephritis [1,14,15,18]. Contrast-enhanced CT of the abdomen and pelvis is supported in high-risk or complicated patients if initial treatment is unresponsive or symptoms worsen [1,2,8,10,15,17-19]. In general, contrast-enhanced CT of the abdomen and pelvis should be delayed 72 hours after initiation of therapy [1,8,14-21].
Acute Pyelonephritis. Acute Pyelonephritis diagnosis of acute extrarenal conditions including cholecystitis (n = 1), liver abscess (n = 1), and appendicitis (n =1), which were all subsequently diagnosed with contrast-enhanced CT [19]. In the absence of a history of renal stones, the benefit of performing unenhanced CT in combination with contrast- enhanced CT is negligible in a complicated patient with suspected APN. In a small retrospective study of adult patients with clinical and laboratory suspicion of APN who all underwent triphasic abdominal CT (n = 100), the accuracy of the nephrographic phase among 2 readers for diagnosis of APN was 90% to 92% and for diagnosis of urolithiasis was 96% to 99% [22]. There was no significant difference in the accuracy of the triphasic abdominal CT relative to the nephrographic phase only [22]. In a prospective nonrandomized data collection study of patients with a final diagnosis of APN (n = 827), the detection rate of APN was 84.4% (445/527) by abdominal CT and only 40% (72/180) by abdominal US [10]. Although the detection rate of urolithiasis and hydronephrosis were similar by abdominal CT and abdominal US, the rate of detection of renal abscess was 4.0% (21/527) by abdominal CT and only 1.1% (2/180) by US [10]. US, CT, and MRI can show evidence of chronic pyelonephritis, including renal scarring, atrophy and cortical thinning, hypertrophy of residual normal tissue, and renal asymmetry [1,8,14,15,17,19,20]. Advantages of abdominal CT and US over abdominal MRI may include superior detection of urolithiasis, and CT may be superior to US and MRI in detection of gas in emphysematous pyelonephritis [1,14,15,18]. Contrast-enhanced CT of the abdomen and pelvis is supported in high-risk or complicated patients if initial treatment is unresponsive or symptoms worsen [1,2,8,10,15,17-19]. In general, contrast-enhanced CT of the abdomen and pelvis should be delayed 72 hours after initiation of therapy [1,8,14-21].