Comparison of bone scan, computed tomography, and magnetic resonance imaging in the diagnosis of active sacroiliitis.

Quantitative bone scan (QBS), computed tomography (CT), and magnetic resonance imaging (MRI) have each been used to confirm the diagnosis of active sacroiliitis (SI) in patients with low back pain (LBP). The authors prospectively evaluated 19 patients referred for symptoms of possible inflammatory LBP (group I), 26 seronegative spondyloarthropathy (SNSP) patients with LBP (group II, inflammatory or mechanical), and 5 SNSP patients without LBP (group III) to determine which radiological scan alone or in combination with other serological tests (Westergren erythrocyte sedimentation rate, C-reactive protein, HLA-B27, immunoglobulin A) was most useful in confirming a clinical diagnosis of active inflammatory SI. All patients were followed up for a minimum of 1 year to confirm the clinical diagnosis and evaluate response to therapy. Eight of 19 group I patients had active SI clinically or on plain radiographs on follow-up evaluation. Of these patients, 5 had abnormal QBS (71%), 3 had abnormal CT scans (38%), and 8 had abnormal MRI scans (100%, type I lesions). These type I MRI lesions were indicative of active inflammation manifested as subcortical bone marrow edema. The remaining 11 group I patients had negative scans for SI. Ten of 26 group II patients with LBP had SI diagnosed clinically and confirmed with positive QBS (60%), CT (100%), and MRI (100%, type I lesions). The remaining 16 group II patients had mechanical LBP without active SI clinically and had negative QBS (88%), CT (19%), and MRI (100%, normal or type II lesions). These type II MRI lesions represented old postinflammatory lesions with either fibrosis or fat replacement. All 5 group III patients had negative scans for active SI. Three patients (2 group I and group II) with inflammatory SI treated with sulfasalazine showed marked improvement on serial MRI scans. Westergren erythrocyte sedimentation rate, C-reactive protein, immunoglobulin A, and CT scan alone or in combination with other tests were not reliable predictors of active SI. Positive QBS and HLA-B27 tests were the best combination of screening tests with 82% predictability of inflammatory SI in whites, and QBS alone had an 80% predictability in black patients. However, MRI, which had 100% predictability, was the best single test for confirming active inflammatory SI.

Segmental stenosis of the renal artery: pattern recognition of tardus and parvus abnormalities with duplex sonography.

Segmental renal artery branches within the renal sinus were prospectively evaluated with color Doppler imaging and pulsed-Doppler spectral analysis in 56 patients before angiography. Waveforms were evaluated for the tardus and parvus abnormalities of prolonged acceleration time, diminished acceleration index, and loss of the normal early systolic compliance peak/reflective-wave complex (ESP). Findings obtained with these parameters were compared with the subsequent findings on angiograms to ascertain their efficacy in detection of hemodynamically significant (greater than or equal to 60%) renal arterial stenosis (RAS), which was present in 32 kidneys in 26 patients. Simple pattern-recognition analysis of ESP proved to be the best of the three parameters. Loss of ESP enabled identification of RAS with 95% sensitivity, 97% specificity, a 92% positive predictive value, a 98% negative predictive value, a 96% overall accuracy. On the basis of the high technical success rate, high sensitivity and specificity, and short examination time, waveform analysis for detection of tardus-parvus abnormalities, especially loss of ESP, of the segmental artery is recommended as an alternative to direct examination of the main renal arteries for evaluation of RAS.

Reduced bone-mineral content is a risk factor for hip fractures.

To evaluate skeletal osteopenia as a risk factor for hip fractures, we measured bone-mineral content in 18 postmenopausal women (aged 50 to 85 years) within 5 days of sustaining a nontraumatic hip fracture. We compared these findings to those in 50 women without a hip fracture who were matched for age, postmenopausal years, height, and weight to the study participants. With the use of dual-photon absorptiometry, the hip fracture patients were found to have a significantly reduced mean bone-mineral content (P less than .005) at three sites in the unaffected hip and a marginally lower mean value (P less than .057) in the lumbar spine as compared to the controls. Other findings in the fracture group included a history of little physical activity, diminished visual acuity, and a somewhat high prevalence of psychiatric/organic brain disorders. Reduced bone mass is an important risk factor for hip fractures. However, other conditions such as physical inactivity, reduced visual acuity, and cognitive impairment may also affect the tendency to fall and/or the ability to cushion the impact of a fall and thus further increase the risk of fracture occurrence.

Malacoplakia of the prostate sonographically mimicking carcinoma.

Malacoplakia is an uncommon granulomatous inflammatory disorder that usually affects the urinary bladder and only rarely affects the prostate. Prostatic malacoplakia was detected in five patients by means of transrectal sonography and confirmed by means of ultrasound-directed transrectal biopsy. Hypoechoic peripheral zone lesions, which are suggestive of carcinoma, were found in all five patients, including two with capsular irregularity and one with a lobular prostatic contour suggesting stage C disease. The results of this study suggest that, with the increased use of sonographically directed transrectal biopsy, prostatic malacoplakia may be found to be more common than previously suspected.

The retrorenal spleen. Implications for percutaneous left renal invasive procedures.

An uncommon but potentially disastrous situation for invasive percutaneous renal procedures is the presence of the spleen behind the upper left kidney. We have termed this anatomic variant "retrorenal spleen." In a computed tomographic (CT) review of 73 patients aged 16 to 86, we found a frequency of retrorenal spleen of 21.1% in the supine and 15.4% in the prone patient. In most individuals with this variant, the spleen was behind the lateral fifth and the superior fourth of the left kidney. The majority (80.0%) of these patients were age 50 or over. However, in only 7.6% would the posterior splenic position pose a risk to posterolateral percutaneous approaches of less than 30 degrees into the upper left collecting system. No patient had retrorenal spleen at the mid-hilar level in either the supine or prone position. Posterolateral approaches up to 40 degrees into the renal hilus are 100% safe from intervening spleen.

Differential diagnosis of prolonged cortical retention of radiotracer in technetium-99m DTPA renal scintigraphy.

The mechanisms of prolonged renal cortical tracer retention in Tc-99m DTPA scintigraphy are discussed and a variety of examples are presented.