Penetrating stab wounds to the abdomen: use of serial US and contrast-enhanced CT in stable patients.

PURPOSE: To evaluate the usefulness of computed tomography (CT) and ultrasonography (US) for the initial assessment of penetrating abdominal stab wounds in patients who presented to the emergency department without indication for immediate laparotomy. MATERIALS AND METHODS: During 36 months, 32 patients with a penetrating stab wound to the abdomen were examined with serial US (at admission and 12 hours later) and helical CT, with contrast material administered orally, intravenously, and rectally. Presence of hemoperitoneum and integrity of solid and hollow viscera were evaluated with both methods. Sonograms were interpreted by the radiologist who performed the examination, and CT images were independently evaluated by two radiologists. Findings of both techniques were compared with clinical outcome and/or surgical findings. RESULTS: One (3.1%) of 32 patients required surgery: Surgical findings were massive hemoperitoneum and an extensive hepatic laceration. Both US and CT depicted these abnormalities. Thirty-one (96.9%) patients were treated conservatively, without surgery, and remained asymptomatic during 28 days of clinical follow-up after discharge from the hospital. US and/or CT showed intraperitoneal abnormalities in 21 of these patients. In 11 patients, both methods showed no evidence of visceral injury or hemoperitoneum, and none of these patients required surgery. CONCLUSION: Serial US and CT help guide treatment for stable patients with penetrating stab injuries to the abdomen.

Malignant hilar and perihilar biliary obstruction: use of MR cholangiography to define the extent of biliary ductal involvement and plan percutaneous interventions.

PURPOSE: To determine the usefulness of magnetic resonance (MR) cholangiography in defining the extent of biliary ductal involvement in patients with malignant hilar and perihilar biliary obstruction and to evaluate whether findings at MR cholangiography alone are sufficient to plan percutaneous interventions in these patients. MATERIALS AND METHODS: Twenty-nine patients with malignant hilar and perihilar biliary obstruction were examined with MR cholangiography. Two radiologists evaluated MR images and determined the extent of biliary ductal involvement. A hypothetical plan for biliary drainage was established prior to any intervention. All patients underwent percutaneous cholangiography, and 27 of 29 patients also underwent biliary drainage and/or stent placement within 7 days after MR cholangiography. By using direct cholangiography as the standard of reference, the usefulness of MR cholangiography in defining the extent of biliary ductal involvement was determined. The type of drainage performed was compared with the type that had been anticipated at MR cholangiography. RESULTS: MR cholangiography was adequate in helping predict the extent of biliary ductal involvement in 28 (96%) of 29 patients and led to underestimation of the extent of the disease in one patient. The therapeutic plan anticipated with MR cholangiography matched the one actually used in 24 (83%) of 29 patients. CONCLUSION: The high accuracy of MR cholangiography for defining extent of ductal involvement in patients with malignant hilar and perihilar obstruction allows adequate planning of percutaneous interventions in a majority of patients.

Traumatic disruption of the pancreatic duct: diagnosis with MR pancreatography.

OBJECTIVE. We evaluated the ability of MR pancreatography to reveal traumatic disruptions of the pancreatic duct compared with retrograde pancreatography. CONCLUSION. MR pancreatography is an adequate noninvasive test for the detection of complete traumatic disruptions of the main pancreatic duct. MR pancreatography is especially useful for delineating the segments of the duct that cannot be evaluated with retrograde pancreatography.

Focal arterial injuries of the proximal extremities: helical CT arteriography as the initial method of diagnosis.

PURPOSE: To present our experience with helical computed tomographic (CT) arteriography as the initial diagnostic examination in patients suspected to have focal arterial injuries of the proximal extremities. MATERIALS AND METHODS: During 19 months, 142 arterial segments in the proximal portions of the extremities of 139 patients with trauma were evaluated with helical CT arteriography. CT arteriograms were interpreted on site by the radiologist in charge of emergency procedures and retrospectively with consensus interpretation between two radiologists. CT study quality and the presence of arterial injuries were noted. CT arteriographic findings were compared with those of surgery, conventional arteriography, and/or clinical follow-up. RESULTS: Five (3.6%) patients had nondiagnostic studies and underwent conventional arteriography. In the remaining 137 arterial segments in 134 patients, helical CT arteriography demonstrated arterial injuries in 61 segments and normal arteries in 76 segments. These segments were treated initially with surgery (55 segments) or endovascular intervention (four segments) or were observed (78 segments); 77 of the 78 observed segments remained stable at 3-18 months (mean follow-up, 5.2 months). There were no differences between the on-site and consensus interpretations (kappa = 1.0). The sensitivity of CT arteriography was 95.1%, and the specificity was 98.7%. CONCLUSION: Helical CT arteriography can be performed as the initial diagnostic method in most patients suspected to have focal arterial injuries of the proximal portions of the extremities.

Dosis letal 50 de lorazepam en raton (Mus musculus) Albino, cepa suizo-icr / Letal dose 50 (LD50) of lorazepam in albino mice (Mus musculus), swiss ICR strain

Objetivo: Como un primer paso para estudiar la toxicidad conjunta de mezclas de escopolamina y benzodiacepinas (nueva burundanga) se determinó la dosis letal 50 (DL50) del lorazepam en ratones (Mus musculus) albinos, cepa suizo ICR. Método: Se utilizaron 60 ratones machos adultos, asignados aleatoriamente a cinco grupos experimentales y uno de control. La dosis de lorazepam administrada por vía intraperitoneal a cada grupo fue: 10 mg/kg al grupo I, 20 mg/kg al grupo II, 40 mg/kg al grupo III, 80 mg/kg al grupo IV, y 160 mg/kg al grupo V. Al grupo de control se le administró solamente la solución vehículo. Se registró la mortalidad durante 15 días después de la administración y se realizó necropsia de los animales muertos durante el ensayo y de los supervivientes al final del mismo. Los datos fueron procesados mediante análisis de probit y estimación de la función de supervivencia. Resultados: La DL50 estimada fue 90.71 mg/kg, con intervalo de confianza del 95 por ciento entre 65,02 y 150,13 mg/kg. La mortalidad se produjo durante los primeros seis días después de la administración de dosis superiores a los 80 mg/kg, siendo mayor en las primeras 48 horas. Conclusiones: La DL50 de lorazepam estimada en nuestro estudio es aproximadamente el doble de la reportada, lo cual sugiere una mayor resistencia de la cepa utilizada en este experimento. El período crítico para la intoxicaciones por lorazepam abarca las primeras 48 horas

Diagnosing bile duct stones: comparison of unenhanced helical CT, oral contrast-enhanced CT cholangiography, and MR cholangiography.

OBJECTIVE: In this investigation we compared the diagnostic performance of unenhanced helical CT, oral contrast-enhanced CT cholangiography, and MR cholangiography for the diagnosis of choledocholithiasis. SUBJECTS AND METHODS: Fifty-one patients referred for endoscopic retrograde cholangiography of suspected biliary stones were studied with unenhanced helical CT, MR cholangiography, and helical CT performed after oral administration of a cholangiographic contrast agent (iopodic acid). The studies were randomized for interpretation. Two radiologists evaluated the images by consensus and determined the presence and location of stones. We used retrograde cholangiography findings as the standard of reference. Sensitivity and specificity (with 95% confidence intervals [CIs]) of the three examinations were calculated and compared using the exact form of the McNemar test. RESULTS: Bile duct stones were revealed with retrograde cholangiography in 26 patients (51%). Sensitivity was 65% (95% CI, 44.4-82%) for unenhanced helical CT, 92% (95% CI, 73-99%) for CT cholangiography, and 96% (95% CI, 78-99%) for MR cholangiography. Specificity was 84% (95% CI, 63-95%) for unenhanced helical CT, 92% (95% CI, 73-99%) for CT cholangiography, and 100% (95% CI, 83-100%) for MR cholangiography. The sensitivity of CT cholangiography and MR cholangiography was significantly higher than that of unenhanced helical CT (p<0.01). Differences in specificity were not significant. CONCLUSION: Our results indicate that oral contrast-enhanced CT cholangiography and MR cholangiography are significantly more sensitive than unenhanced helical CT for the detection of bile duct calculi.

Diagnosis of arterial injuries caused by penetrating trauma to the neck: comparison of helical CT angiography and conventional angiography.

PURPOSE: To determine the sensitivity and specificity of helical computed tomographic (CT) angiography in the diagnosis of carotid and vertebral arterial injuries caused by penetrating neck trauma. MATERIALS AND METHODS: A prospective study was conducted during 24 months in 60 patients with penetrating neck trauma who were referred for conventional angiography owing to clinical suspicion of arterial injury. In the patient population, 146 arteries (77 carotid, 69 vertebral) were studied by means of conventional angiography. In all patients, conventional angiography and helical CT angiography were completed within 6 hours. Two radiologists interpreted helical CT angiographic studies by means of consensus. Conventional angiography was the standard of reference for determining the sensitivity and specificity of helical CT angiography. RESULTS: Conventional angiograms showed arterial injuries in 10 (17%) of 60 patients. Conventional angiographic findings were arterial occlusion (n = 4), arteriovenous fistula (n = 2), pseudoaneurysm (n = 3), pseudoaneurysm with arteriovenous fistula (n = 1), and normal arteries (n = 136). Nine of 10 arterial injuries and all normal arteries were depicted adequately at helical CT angiography. Sensitivity of helical CT angiography was 90%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 98%. CONCLUSION: The sensitivity and specificity of helical CT angiography are high for detection of major carotid and vertebral arterial injuries resulting from penetrating trauma.

Biliary obstruction: findings at MR cholangiography and cross-sectional MR imaging.

Twenty-two patients with malignant biliary obstruction and 21 patients with suspected obstruction of biliary-enteric anastomoses were evaluated over a 12-month period with magnetic resonance (MR) cholangiography and cross-sectional MR imaging. In patients with malignant obstruction, MR cholangiography helped accurately determine the status of the biliary ductal system by identifying the exact location and extent of the obstruction and the severity of duct dilatation. In so doing, MR cholangiography helped determine whether percutaneous transhepatic cholangiography with antegrade stent placement or retrograde cholangiography with stent placement constituted the more suitable treatment. Cross-sectional MR imaging was necessary to identify the organ of tumor origin, define the tumor margins, and determine the stage of disease. This information helped evaluate the appropriateness of curative surgical therapy versus palliative drainage procedures. In patients with biliary-enteric anastomoses, MR cholangiography clearly depicted the site of the anastomosis and demonstrated the status of the intrahepatic ducts, thereby helping determine which patients would benefit from undergoing antegrade duct cannulation with a drainage procedure or perhaps balloon dilation. In some of these patients, MR cholangiography was sufficient to help plan therapeutic intervention. MR cholangiography also demonstrates the presence and size of biliary stones and associated findings such as intraductal tumor growth. In addition, MR cholangiography may obviate retrograde cholangiography, which can be technically difficult to perform.

Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities.

PURPOSE: The purpose of this work was to assess the performance of helical CT angiography (CTA) in the diagnosis of injuries to large arteries of the extremities. METHOD: We performed helical CTA on 45 consecutive patients referred for conventional angiography for evaluation of suspected arterial injuries after sustaining trauma to the extremities (13 upper, 32 lower). Two radiologists interpreted the helical CTA studies independently. Diagnostic performance parameters evaluated included sensitivity, specificity, receiver operating characteristic (ROC) curves, and interobserver agreement (kappa statistics). Conventional angiography was used as the standard of reference for determination of final diagnoses. RESULTS: Forty-three of 45 patients (96%) had diagnostic helical CTA examinations. Final diagnoses in these 43 patients were arterial occlusion (n = 7), partial obstruction (n = 3), pseudoaneurysm (n = 5), arteriovenous fistula (n = 1), pseudoaneurysm and arteriovenous fistula (n = 3), and normal findings (n = 24). Sensitivity and specificity were 90% [95% confidence interval (CI), 80-99] and 100% (95% CI, 99-100), respectively, for Reader 1 and 100% (95% CI, 99-100) and 100% (95% CI, 99-100), respectively, for Reader 2. ROC curve analysis revealed high diagnostic performance, with areas under the curve of >0.9 for both readers. Interobserver agreement was 0.9. CONCLUSION: The diagnostic performance of helical CTA for detection of major injuries of large arteries of the extremities is high.