The prevalence and patterns of intraluminal air in acute appendicitis at CT.

The purpose of this study is to investigate if the presence and distribution of intraluminal air in the appendix contributes to the computed tomography (CT) diagnosis of appendicitis. We identified 100 consecutive patients (57 men and 43 women; mean age, 38) with CT prior to appendectomy for acute appendicitis over a 5-year period and a control group of 100 consecutive patients (29 men and 71 women; mean age, 39) who underwent CT for acute abdominal pain without appendicitis. Patients were scanned using multidetector row CT scanners at 1.25 or 5-mm slice thickness, peak tube voltage of 120 kVp, and milliamperse automatically adjusted to attain a noise index of 12. Ninety-two of 100 study patients and 95 of 100 controls received 150 mL intravenous contrast. Two independent readers noted the presence and distribution pattern of intraluminal air in the appendix, appendiceal diameter, wall hyperemia, wall thickening (>3 mm), and wall stratification and presence of any secondary signs of appendicitis including fat stranding and free fluid. Data were compared between groups using Fisher's exact test and Student's t test. Intraluminal air in the appendix was more common in control patients versus patients with appendicitis (66 of 100 versus 27 of 100, p < 0.001). No significant differences in the patterns of intraluminal air were found between cases and controls. Among appendicitis cases, there was no significant difference in mean appendiceal diameter (12.8 versus 12.0, p = 0.20) or number of CT signs of appendicitis (1.93 versus 1.86, p = 0.78) in cases with intraluminal air versus without. No case of appendicitis demonstrated intraluminal air without secondary signs of appendicitis. Although intraluminal air is sometimes assumed to exclude a diagnosis of appendicitis, it is actually a common finding seen in up to 27 % of cases at CT. The pattern of intraluminal air was not helpful in differentiating a normal appendix from appendicitis.

The negative appendectomy rate: who benefits from preoperative CT?

OBJECTIVE: The purpose of this article is to determine the negative appendectomy rates of patients who did and did not undergo preoperative CT and to determine, more specifically, whether men benefit from preoperative CT. MATERIALS AND METHODS: We identified 512 patients who had a nonincidental appendectomy between July 1, 2002, and June 30, 2007. Pathology records were compared with a radiology records search to determine which patients underwent preoperative CT. Proportions of patients were compared between groups using the Fisher exact test. RESULTS: Of 512 patients who had a nonincidental appendectomy, 465 (91%) underwent preoperative CT, and 47 (9%) underwent appendectomy only on the basis of clinical findings. Overall, 22 of 465 patients (4.7%) who underwent preoperative CT had a negative appendectomy compared with six of 47 patients who did not undergo preoperative imaging (negative appendectomy rate, 12.7%; p = 0.03). Among men, six of 237 (2.5%) with preoperative CT had a negative appendectomy, versus five of 42 without imaging (negative appendectomy rate, 11.9%; p = 0.01). CONCLUSION: The negative appendectomy rate was decreased for adult patients who underwent preoperative CT compared with patients who did not undergo preoperative imaging. Although most prior studies have suggested that CT is efficacious only in decreasing the negative appendectomy rate among women, we found that men benefit from CT as well.

Acute appendicitis: clinical outcome in patients with an initial false-positive CT diagnosis.

PURPOSE: To investigate the clinical outcome in patients with a diagnosis of appendicitis at computed tomography (CT) in whom treatment is deemed unnecessary after clinical evaluation. MATERIALS AND METHODS: After institutional review board approval, 2283 patients (856 men, 1427 women; mean age, 46 years; age range, 18-99 years) who underwent CT because they were suspected of having appendicitis between 2002 and 2007 were retrospectively identified. CT reports were reviewed, and the likelihood of appendicitis was assigned a score on a five-point scale: score 1, definitely absent; score 2, nonvisualized appendix with no secondary signs of inflammation; score 3, equivocal; score 4, probable; and score 5, definitely present. Diagnosis of appendicitis at CT was considered a false-positive result if the CT report was classified as probable or definite appendicitis but the patient was not treated within 4 days. Cases with false-positive results were reviewed by two readers blinded to patient outcome, supporting clinical data, and prospective scan interpretation, and a grade was assigned by using the same scale. Medical records were reviewed to determine outcomes. Descriptional statistics were used. RESULTS: Overall, 516 (23%) of 2283 patients had CT findings of probable or definite appendicitis. Thirteen (3%) of 516 patients did not receive immediate treatment for appendicitis. Of these, five (38%; 95% confidence interval: 18%, 65%) underwent later appendectomy with proved appendicitis after a mean interval of 118 days (range, 5-443 days). Seven (54%) of 13 patients never developed appendicitis across a mean follow-up of 583 days (range, 14-1460 days). One (8%) of 13 had a normal appendix at eventual surgery. CONCLUSION: Five of 13 patients with CT findings of appendicitis and reassuring clinical evaluation results in whom immediate treatment was deferred ultimately returned with appendicitis. In patients with CT results positive for appendicitis and benign or atypical clinical findings, a diagnosis of chronic or recurrent appendicitis may be considered.

Supratentorial abnormalities in the Chiari II malformation, II: tectal morphologic changes.

OBJECTIVE: The sonographic diagnosis of fetal myelomeningocele has improved mainly because the diagnostic focus has shifted from observation of spinal manifestations to observation of cranial abnormalities. Intracranial diagnostic criteria rely on abnormalities in the posterior fossa. We describe abnormalities in tectal morphologic characteristics that, although well described on magnetic resonance imaging, have received little attention in the sonographic literature. This study analyzed the frequency of this observation and technical aspects that improve its visualization. METHODS: From a database of obstetric sonograms, we identified all cases of sonographically detected myelomeningocele. The search covered the years 1999 to 2007. We retrospectively reviewed the fetal intracranial findings with special attention to elongation or "beaking" of the tectum. RESULTS: A total of 89 fetuses were identified. The mean and median gestational ages were 22 weeks 4 days and 22 weeks 2 days, respectively. Of the 89 cases, 59 (66%) had an abnormal tectal shape. The abnormality was seen in 77% of cases judged to be suboptimally visualized and 62% of cases with good visualization. Tectal abnormalities were seen equally well in fetuses before and after 24 weeks. Finally, tectal abnormalities were seen more frequently as the severity of posterior fossa findings increased. CONCLUSIONS: Tectal morphologic alteration is a common supratentorial feature of the Chiari II malformation on prenatal sonography both before and after 24 weeks' gestation. Its frequency increases with the severity of posterior fossa abnormalities. Therefore, it may be useful as a supratentorial indicator of both the presence and, potentially, the severity of the Chiari II malformation.

Sonography of the scrotum: case-based review.

OBJECTIVE: We discuss five scenarios in which sonography is useful for diagnosing scrotal abnormalities, including painful scrotal disorders, an incidental disorder, and scrotal masses. Practice questions are included for your review. CONCLUSION: Sonography is the primary diagnostic tool for diagnosing disorders in the scrotum.

Sonography of the scrotum: self-assessment module.

Sonography is the primary technique for the imaging evaluation of diseases of the scrotum. Imaging features of disease should be correlated with clinical features to guide management. The educational objectives of this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of clinical and sonographic features of diseases of the scrotum.

CT of acute appendicitis: can diagnostic accuracy serve as a practical performance metric for readers specialized in abdominal imaging?

PURPOSE: To investigate diagnostic accuracy for acute appendicitis at computed tomography (CT) as a performance metric for radiologists specialized in abdominal imaging. MATERIALS AND METHODS: We retrospectively identified six attending abdominal imagers who each independently interpreted over 100 CT studies for suspected acute appendicitis. RESULTS: The mean number of studies per reader was 311 (range, 129-386). Mean reader diagnostic accuracy was 95.0% (range, 91.4-97.1%). Only one had a diagnostic accuracy (91.4%) that was significantly lower than all others. CONCLUSION: Diagnostic accuracy for acute appendicitis at CT may be an impractical performance metric for radiologists specialized in abdominal imaging.