Relationship between duration of pain and secondary signs of obstruction of the urinary tract on unenhanced helical CT.

OBJECTIVE: The objective of this study was to investigate the relationship between duration of flank pain and the frequency of secondary signs of ureteral obstruction on unenhanced helical CT. SUBJECTS AND METHODS: The duration of flank pain was prospectively determined in 227 consecutive patients diagnosed with acute ureterolithiasis on unenhanced helical CT. These CT studies were evaluated for the presence or absence of perinephric stranding, ureteral dilatation, perinephric fluid, collecting system dilatation, periureteral stranding, and nephromegaly. The frequency of each sign was determined as a function of the duration of pain. RESULTS: The frequency of moderate or severe perinephric stranding increased from 5% at 1--2 hr to 51% at 7--8 hr (p < 0.001); ureteral dilatation increased from 84% at 1--2 hr to 97% at more than 8 hr (p < 0.03); moderate or severe perinephric fluid increased from 0% at 1--2 hr to 22% at 3--4 hr (p < 0.03); collecting system dilatation increased from 68% at 1--2 hr to 89% at 7-8 hr (p < 0.03); periureteral stranding increased from 35% at 1--2 hr to 76% at 7--8 hr (p < 0.004); and nephromegaly increased from 40% at 1--2 hr to 54% at 7--8 hr (p < 0.36). CONCLUSION: All CT secondary signs of ureteral obstruction except nephromegaly showed a significant increase in frequency as duration of flank pain increased. This observation may explain why the CT studies of some patients with acute ureterolithiasis show negative findings for some or all CT secondary signs of obstruction. Therefore, knowledge of the duration of pain is important when interpreting unenhanced CT studies in patients with acute ureterolithiasis.

Magnetic resonance imaging of children without sedation: preparation with simulation.

OBJECTIVE: It was hypothesized that a scanner simulator that replicates the magnetic resonance imaging (MRI) environment could be used to prepare pediatric subjects for successful completion of a diagnostic-quality MRI examination without pharmacological sedation. METHOD: Sixteen healthy children, 6 to 17 years of age, were matched for age and sex with 16 psychotropic medication-naive children with obsessive-compulsive disorder. Distress was measured throughout simulation and scanning procedures using heart rate and a self-report distress scale. Ten healthy children, 6 to 17 years of age, also underwent the same actual MRI scanning procedure but did not undergo the simulation scanning procedure. RESULTS: Significant decreases in heart rate and self-reported distress level were observed in all subjects during the simulator session that were maintained to the end of the actual scanner experience. All subjects successfully completed MRI examinations without chemical restraint. Subjects who were not trained in the simulator had higher heart rates and self-reported distress levels in the actual scanner than did simulation-trained subjects. CONCLUSIONS: Simulation without pharmacological sedation successfully prepared pediatric subjects in this pilot study for high-quality MRI studies. Subject preparation may be an alternative procedure to sedation for routine MRI examination in healthy and anxious children 6 years of age and older.