Improved visualization of choledocholithiasis by sonography

During a 20 month period, real-time sonography performed on 26 patients achieved an overall sensitivity of 75% for detecting choledocholithiasis. Although previous publications have stressed very low sensitivities for diagnosing choledocholithiasis (13%-55%), it was postulated that the reasons for these disappointing results are primarily related to technique. Most laboratories evaluate the distal common bile duct (where most calculi are located) by obtaining parasagittal scans. Detection of choledocholithiasis can be substantially improved by scanning the intrapancreatic part of the bile duct in a transverse fashion with the patient in an erect position. Advantages of the transverse view include the ability to demonstrate the distal common bile duct in a high percentage of patients and to differentiate shadowing caused by duodenal gas from ductal calculi. The proximal duct is best imaged by obtaining parasagittal scans with the patient in a supine left posterior oblique position. Using these scanning techniques, eight (89%) of nine proximal and 16 (70%) of 23 distal calculi were visualized.     

Early pregnancy complications: endovaginal sonographic findings correlated with human chorionic gonadotropin levels

Endovaginal sonography results were compared with quantitatively determined human chorionic gonadotropin (hCG) levels in 84 women referred for early pregnancy complications. Of the 27 with normal intrauterine pregnancies, an intrauterine gestational sac was prospectively identified in one of five cases (20%) in which hCG levels were below 500 IU/L (Second International Standard), four of five (80%) with hCG levels of 500-1,000 IU/L, and all 17 with hCG levels above 1,000 IU/L. In comparison, 17 of the 26 women with ectopic pregnancies (65%) had hCG levels greater than 1,000 IU/L, and none of the 26 had an intrauterine gestational sac. Endovaginal sonography demonstrated an adnexal mass and/or a gestational sac-like structure in 16 of the 17 cases (94%) in which hCG levels were above 1,000 IU/L, compared with only three of the nine (33%) with lower hCG levels (P less than .01). These findings indicate that an intrauterine gestational sac should be normally visualized with endovaginal sonography when the hCG level exceeds 1,000 IU/L, and that visualization of an extrauterine gestational sac and/or adnexal mass is significantly more likely in ectopic pregnancies when the hCG level exceeds 1,000 IU/L.     

Optimum perception of odor intensity by humans

The sniff duration that provides optimum perception of odor intensity was determined for 17 humans. Subjects were trained to match the duration of their sniff to the duration of a buzzer that sounded for 0.2, 0.5, 1.0 or 2.0 sec. Sniff characteristics were monitored with a hot wire anemometer and an oscilloscope. Intensity estimates were obtained at the four durations for three concentrations of phenyl ethanol, butanol and propionic acid. Optimum perception of intensity occurred between 0.39 and 0.64 sec for phenyl ethanol and propionic acid and a value of no more than 1.63 sec is proposed for butanol. The longer duration for butanol is attributed to the delayed response of nerves in the throat which appear to respond to this odorant but not to the others. The complexity of the intensity sensation and implications of the results for neurophysiological studies of intensity coding are discussed and the properties of an olfactometer for odor intensity measurements are outlined.     

The effect of traction on compartment pressures during intramedullary nailing of tibial-shaft fractures. A prospective randomised trial

Our aim was to study the effect of traction on the compartment pressures during intramedullary nailing of closed tibial-shaft fractures. Thirty consecutive patients with Tscherne C1 fractures were randomised into two groups. Sixteen patients underwent intramedullary nailing of the tibia with traction and 14 patients without traction. Compartment pressures were measured before the application of traction or commencement of the procedure and at the end of the procedure. The data collected was analysed using Students t test. There was no statistically significant difference (p>0.05) in the pre-operative mean compartment pressures for both groups. The mean post-operative measurements were higher in all four compartments in the traction group (p<0.05). None of the pressures reached the critical level. These results show that traction as an aid unnecessarily increases compartment pressures.

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Résumé Notre but était détudier leffet de la traction sur la tension compartimentale pendant lenclouage centromédullaire des fractures tibiales fermées. Trente malades consécutifs avec des fractures Tscherne C1 ont été randomisés dans deux groupes. Seize malades ont subi un enclouage centromédullaire tibial avec traction et quatorze malades sans traction. Les pressions compartimentales ont été mesurées avant la mise en traction ou au commencement de lopération et à la fin de lopération. Les données ont été analysées avec le Student t-test. Il ny avait aucune différence statistiquement significative (p>0.05) dans les pressions moyennes préopératoires des compartiments pour les deux groupes. Les mesures postopératoires moyennes étaient plus élevées dans les quatre compartiments dans le groupe avec traction (p<0.05). Aucune des pressions nest arrivée au niveau critique. Ces résultats montrent que la traction augmente les pressions des compartiments.

     

Ultrasonographic identification of dilated intrahepatic bile ducts and their differentiation from portal venous structures.

The appearance of dilated intrahepatic bile ducts was evaluated on ultrasonograms of 50 patients with proven extrahepatic biliary obstruction. Five characteristic changes allowed differentiation between biliary and portal venous systems. These changes included: 1) alteration in the anatomic pattern adjacent to the main right portal venous segment and the main portal vein bifurcation. 2) Irregular walls of dilated bile ducts. 3) Stellate confluence of dilated bile ducts. 4) Acoustic enhancement by dilated bile ducts. 5) Peripheral location of dilated bile ducts. Many patients exhibited more than one of these findings. Parasagittal scans of the main right portal vein were the most sensitive for detection of intrahepatic ductal dilatation. Recognition of the characteristic changes and knowledge of the portal venous anatomy makes it possible to diagnose extrahepatic biliary obstruction with a high degree of confidence.