Imaging of acute appendicitis and its impact on negative appendectomy and perforation rates: the St. Paul's experience

PURPOSE

Preoperative imaging of acute appendicitis is widely practised. The aim of this study is to determine the prevalence of preoperative imaging of acute appendicitis in our institution and its effect on the negative appendectomy rate and perforation rates.

METHODS

We undertook a retrospective review of all patients who underwent appendectomy from January 2000 to December 2004. All available preoperative ultrasound (US), computed tomography (CT), and pathology results were reviewed.

RESULTS

A total of 380 appendectomies were performed over this time period for the preoperative diagnosis of acute appendicitis. Fifty-nine patients had histologically normal appendices, giving an overall negative appendectomy rate of 15.5%. Overall, patients who had preoperative imaging showed a lower negative appendectomy rate (11.4%) than did those without imaging (22.2%). Without preoperative imaging, women had a higher negative appendectomy rate (34.3%) than did men (17.4%). Reduction in the negative appendectomy rate was demonstrated with preoperative imaging in both sexes (16.7% and 5.7%, respectively). Also demonstrated is a definite trend toward increased use of preoperative CT and away from US as the sole preoperative imaging modality. This is associated with a reduced negative appendectomy rate.

CONCLUSIONS

The increased use of preoperative imaging, particularly CT, is associated with a decreased negative appendectomy rate and a decreased perforation rate at our institution.

Correlation of virus load in plasma and lymph node tissue in human immunodeficiency virus infection. INCAS Study Group. Italy, Netherlands, Canada, Australia, and (United) States

The impact of long-term changes in plasma viremia, produced by effective combination antiretroviral therapy, on human immunodeficiency virus (HIV) burden within tissue reservoirs is unknown. Fifteen patients who had received at least 1 year of therapy with two or three drug combinations of zidovudine, didanosine, and nevirapine had suitable samples of lymph node tissue obtained by ultrasound-guided core needle biopsy. HIV RNA was extracted from homogenized tissue samples and quantitated using a modified branched DNA assay. Results were correlated with antiretroviral treatment effect on the basis of plasma virus load measurements over the preceding 12-18 months. A statistically significant negative correlation was observed between magnitude of treatment effect on plasma viremia and lymph node virus load. These data suggest that combinations of antiretroviral drugs that produce sustained suppression of plasma HIV RNA may also be able to reduce the virus burden in lymphoid tissues.

Small, asymptomatic angiomyolipomas of the kidney

Ultrasound (US) detected 27 small, asymptomatic renal angiomyolipomas in 18 patients. Twenty-five lesions were diffusely hyperechoic and 2 were heterogeneous. Nephrotomography was positive in 8 out of 12 patients (67%), CT in 12/14 (86%), and angiography in 10/14 (71%). Percutaneous fine-needle biopsy confirmed the diagnosis in 8 out of 12 patients (67%). Nephrotomography and angiography were nonspecific, whereas CT and biopsy were most specific because of the presence of fatty tissue. Angiography helped clarify the degree of vascularity of the masses. If the diagnosis can be made preoperatively, more conservative management can be undertaken.

Subpulmonic empyema masquerading as subphrenic abscess

Since the therapeutic management of an empyema is significantly different from that for a subphrenic abscess it is important to define the location of the diaphragm in relation to an abscess cavity. A patient is presented who underwent unnecessary laparotomy due to misinterpretation of the clinical and radiographic findings.

Grey-scale ultrasonography: a refined tool for differentiating renal mass lesions

Images

Gray-scale ultrasound of billary tract disease. A correlative study with percutaneous transhepatic cholangiography

Gray-scale ultrasound can be useful in the diagnosis of extrahepatic obstructive jaundice by the demonstration of dilatation of the biliary tree. The present study was undertaken to test the specificity and sensitivity of gray-scale ultrasound (US) in the detection of dilation of intrahepatic bile ducts, as compared to percutaneous transhepatic cholangiography (PTC). Forty-seven patients were studied prospectively by both techniques. In 23 patients demonstrated by PTC to have dilated intrahepatic ducts, 18 were detected by US. Of the 11 patients shown to have non-dilated ducts by PTC, all were accurately predicted by US. In 13 cases in which PTC was unsuccessful, the US study showed 12 to be non-dilated and one to be mildly dilated. Ultrasound as a non-invasive technique, should be the primary imaging technique in the evaluation of possible extrahepatic obstructive jaundice.

A study of ankle instability utilizing ankle arthrography

A preclinical and clinical study of ankle arthrography for chronic ankle instability was performed. In the first study, ankle arthrograms were done on 50 cadaver ankles to demonstrate the limits of the normal ankle joint, and it was demonstrated that contrast in tendon sheaths is not a sign of a torn ankle ligament. The second study consisted of investigating ten cases of chronic ankle instability utilizing ankle arthrography. It was concluded that ankle arthrography is helpful in diagnosing torn ankle ligaments if all remaining investigative procedures are negative. A positive ankle arthrogram is proof that a torn capsule and ligament has occurred. However, in this small series a negative a negative arthrogram and a normal talar tilt was still associated with a torn ligament of the ankle.

Parachute accessory anterior mitral valve leaflet causing left ventricular outflow tract obstruction. Report of a case with emphasis on the echocardiographic findings

A case of left ventricular outflow tract obstruction caused by a parachute accessory anterior mitral valve leaflet is presented. The abnormality was detected in an asymptomatic patient by systolic murmur and thrill and was demonstrated by echocardiography, as well as by cardiac catheterization and surgery. These findings are presented. Several previously reported cases of a similar nature are reviewed. An identical case was not found in the English literature.