Long-term outcome of meniscal degeneration in the knee: poor association between MRI and symptoms in 45 patients followed more than 4 years

Knee joint-related symptoms are frequent and the use of MRI as a diagnostic tool is common. About 25% of MRIs show meniscal degeneration (MD). As the natural history of MD has not been well described, we studied the long-term outcome of 50 MDs. 45 patients were initially evaluated by a MRI, and clinical examination and later by another MRI. After 5 years, 38 of the MDs were unchanged, 8 had progressed and 4 regressed. Progression of MD was associated with age over 40 years, trauma during the follow-up period and/or other knee lesions, such as osteoarthrosis and ligament rupture. The clinical findings were consistent with MDs only in 8 cases.     

Three-dimensional virtual cholangioscopy: a reliable tool for the diagnosis of common bile duct stones

OBJECTIVE: Our goal was to evaluate the clinical reliability of a new software system employing 3-dimensional (3D) virtual anatomic reconstruction and intraluminal virtual exploration for detection of choledocholithiasis and preoperative visualization of the biliary anatomy. SUMMARY BACKGROUND DATA: Virtual reality systems have been proposed for gastroscopy, bronchoscopy, and colonoscopy, as well as for the 3D reconstruction of liver anatomy and hepatic lesions. The impact of these systems in preoperative diagnostics has not been established due to the lack of large clinical series evaluating their reliability. METHODS: From November 2000 to July 2002, all patients presenting to our Institute with suspected choledocholithiasis were prospectively included in the study. All patients underwent conventional magnetic resonance cholangiopancreatography (MRCP) and either intraoperative cholangiogram (IOC) or endoscopic retrograde cholangiopancreatography (ERCP). The digital data from MRCP were incorporated into an original virtual reality software system to generate a 3D reconstruction. All 3D reconstructions were evaluated by a surgeon and a computer software engineer who were blind to the results of the IOC or ERCP. Sensitivity and specificity were then calculated based on the results of either the IOC or ERCP. RESULTS: Sixty-five patients were enrolled in the study. The average time required to reconstruct the images into navigable virtual reality was 7.5 minutes (range, 4-13.5). The 3D virtual cholangioscopy had sensitivity and specificity rates of 71% and 91%, respectively, compared with 61% and 86% of the standard MRCP. CONCLUSION:: The 3D virtual cholangioscopy provides detailed preoperative reconstruction of biliary anatomy and reliable identification of choledocholithiasis with acceptable sensitivity and specificity in a clinical setting. Newer software developments may further enhance its accuracy, so that virtual cholangioscopy might challenge or replace more invasive diagnostic measures in the near future.     

Wall shear rates differ between the normal carotid, femoral, and brachial arteries: an in vivo MRI study

PURPOSE: To investigate wall shear rates in vivo in the common carotid, brachial, and superficial femoral arteries using very high resolution magnetic resonance imaging (MRI) phase contrast measurements. MATERIALS AND METHODS: Mean, maximum, and minimum wall shear rate and an oscillatory shear index were measured for 20 volunteers, aged 23.3 +/- 1.9 years, in the three arteries, using phase contrast imaging with 0.0625 mm2 resolution and three-dimensional paraboloid fitting. RESULTS: The superficial femoral artery had the lowest mean (130.3 +/- 13.1 second(-1)), maximum (735.8 +/- 32.4 second(-1)), and minimum (-224.5 +/- 17.0 second(-1)) wall shear rate, as well as the highest oscillatory shear index (0.21 +/- 0.02). All values were significantly different (P < 0.05) from both the brachial artery and the common carotid artery values. The highest mean (333.3 +/- 13.6 second(-1)) and minimum (117.9 +/- 24.5 second(-1)) wall shear rates and the lowest oscillatory shear index (0 +/- 0) were found in the common carotid artery. CONCLUSION: It is possible to measure wall shear rate in vivo in different arteries using MRI with very high resolution. The findings exhibit the in vivo environment of wall shear rates and suggest a nonuniform distribution of wall shear rates throughout the arterial system.     

A novel infraclavicular brachial plexus block: the lateral and sagittal technique, developed by magnetic resonance imaging studies

A new infraclavicular brachial plexus block method has the patient supine with an adducted arm. The target is any of the three cords behind the pectoralis minor muscle. The point of needle insertion is the intersection between the clavicle and the coracoid process. The needle is advanced 0 degrees -30 degrees posterior, always strictly in the sagittal plane next to the coracoid process while abutting the antero-inferior edge of the clavicle. We tested the new method using magnetic resonance imaging (MRI) in 20 adult volunteers, without inserting a needle. Combining 2 simulated needle directions by 15 degrees posterior and 0 degrees in the images of the volunteers, at least one cord in 19 of 20 volunteers was contacted. This occurred within a needle depth of 6.5 cm. In the sagittal plane of the method the shortest depth to the pleura among all volunteers was 7.5 cm. The MRI study indicates that the new infraclavicular technique may be efficient in reaching a cord of the brachial plexus, often not demanding more than two needle directions. The risk of pneumothorax should be minimal because the needle is inserted no deeper than 6.5 cm. However, this needs to be confirmed by a clinical study. IMPLICATIONS: A new infraclavicular brachial plexus block method was investigated using magnetic resonance imaging without inserting needles in the volunteers. The study suggests two needle directions for performance of the block and that the risk of lung injury should be minimal. Expectations need to be confirmed by a clinical study.     

Hemorrhage during isoflurane-nitrous oxide anesthesia: effects of endothelin-A or angiotensin II receptor blockade or both

BACKGROUND: The objective of this study was to determine whether endothelin-A receptor blockade (ETAB) impairs hemodynamic and hormonal regulation compared with controls and angiotensin II receptor blockade (AT1B) during hypotensive hemorrhage in dogs under isoflurane-nitrous oxide anesthesia. METHODS: Six dogs were studied in four protocols: (1) control experiments (controls); (2) ETA blockade using ABT-627 (ETAB); (3) AT1 blockade using losartan (AT1B); and (4) combined AT1B and ETAB (AT1B + ETAB). After a 30-min awake period, isoflurane-nitrous oxide anesthesia was established (1.3 minimum anesthetic concentration). After 60 min of anesthesia, 20 ml blood/kg body weight was withdrawn within 5 min, and the dogs were observed for another hour. Thereafter, the blood was retransfused, and the dogs were observed for a final hour. RESULTS: Anesthesia: Cardiac output decreased in all protocols, whereas mean arterial pressure decreased more in AT1B and AT1B + ETAB than in controls and ETAB. Hemorrhage: After 60 min, cardiac output had decreased less in controls than in all other protocols. Mean arterial pressure decreased more during ETAB than in controls, but most severely during AT1B and AT1B + ETAB. Angiotensin II increased further only in controls and ETAB, whereas vasopressin and catecholamines increased similarly in all protocols. Retransfusion: Mean arterial pressure remained below controls in all protocols but was lowest when the AT1 receptor was blocked. Cardiac output fully recovered in all but the ETAB protocol. CONCLUSIONS: ETAB impairs long-term hemodynamic regulation after hemorrhage and retransfusion during anesthesia despite an activation of vasoconstrictive hormones. This suggests that endothelins have a role in long-term cardiovascular regulation. AT1B impairs both short- and long-term blood pressure regulation during anesthesia and after hemorrhage.     

Albuminuria and cardiovascular risk in hypertensive patients with left ventricular hypertrophy: the LIFE Study

Studies have shown that albuminuria is associated with increased risk for cardiovascular events. We tested the relationship between albuminuria (UACR) and cardiovascular risk in 8206 hypertensive patients with left ventricular hypertrophy included in the LIFE Study. Follow-up was 39,122 patient years. The risk for the primary composite cardiovascular end point increases continuously from the lowest to the highest decile of baseline UACR. No specific threshold could be identified. In conclusion, albuminuria predicts the outcome in the LIFE Study. The risk for cardiovascular morbidity and mortality among hypertensive patients with left ventricular hypertrophy increases at much lower UACR than has been reported in diabetic patients.