Elderly trauma patients admitted to the intensive care unit are different from the younger population.

AIMS: This study was undertaken to investigate the demographic profile of elderly (65 years old and over) patients with severe trauma admitted to the Intensive Care Unit of Auckland Hospital and to compare their characteristics with those of the younger (under 65 years) trauma patients. A further aim was to see if specific areas of potential injury prevention could be identified. METHOD: Data analysis covering ten years, from January 1987 to December 1996, on data extracted from the existing database at the Intensive Care Unit of Auckland Hospital. RESULTS: The elderly comprised 8.7% (183 of 2092) of the trauma admissions during the study period. The elderly, when compared with the younger group, were significantly more likely to be female, New Zealand European and admitted as a result of a fall. They were significantly less likely to be drivers in a road traffic crash or, if a driver, to have a blood alcohol above the legal limit. Mortality in the older group (27.8%) was significantly higher, though median injury severity score (25) and length of stay (57.9 hours) were similar. CONCLUSIONS: Elderly trauma patients in the Intensive Care Unit are a group with distinctive demographics, mechanisms of injury, injury types and outcomes. This information needs to be considered for the future planning of trauma and prevention services in New Zealand.

Masseter muscle volume measured using ultrasonography and its relationship with facial morphology.

The aims of this study were to measure the volume, cross-sectional area, thickness, width, and length of contracted masseter muscles in a sample of adults, four males and six females, using three-dimensional (3D) ultrasonography, and to correlate these measurements with the variations in facial morphology of the sample. The scans were carried out bilaterally using a hand-held probe carrying a magnetic positional sensor, which enabled a computer to reconstruct the images into a 3D array of slices. Measurements were made by the computer from the reconstructed images using specially written software. Cephalometric analysis initially involved seven angular, eight linear, and two proportional variables, but as these were strongly inter-dependent, the variables were reduced to four principal components prior to statistical comparison with the mean muscle variables. The values found for muscle volume, cross-sectional area, and thickness were broadly consistent with those of previous investigators. Volume showed a significant, negative correlation with mandibular inclination including gonial angle (P < or = 0.001), and a significant, positive correlation with total posterior face height and ramus height (P < or = 0.001), and lower posterior face height percentage (P < or = 0.01). Weaker correlations were found for length and thickness. While the results support existing evidence that large masticatory muscles are associated with brachycephalism and vice versa, a cautious interpretation is necessary in view of the small sample size. The 3D ultrasonography system is at an experimental stage and requires further development and evaluation.

Three-dimensional magnetic resonance imaging of the postmortem fetal heart.

Five postmortem fetuses were scanned by magnetic resonance (MR) imaging. Of eight three-dimensional (3D) data sets reconstructed on an MGI workstation, five sets demonstrated detailed 3D fetal cardiac structures, and one depicted clear information regarding the disposition and compression of the heart and lungs in diaphragmatic hernia. This study has shown the potential of 3D MR imaging in support of postmortem examination and for interactive visual teaching of the fetal cardiac structures. The new technique may eventually be of significance in prenatal detection of cardiac abnormalities with the development of fast real-time MR imaging.

Fetal echocardiography in three and four dimensions.

A three-dimensional (3D) acquisition system using an electromagnetic position sensor attached to a standard transducer on an unmodified ultrasound scanner was developed to capture two-dimensional (2D)-fetal echocardiograms at various positions and orientations. Operating in real-time directed M-mode allowed recording of 2D structural images and cardiac motion curves, from which the fetal cardiac phase could be determined. By digitising over 100 image frames for each scanning sequence, and by selecting frames at particular phases, 3D views of the fetal heart were reconstructed for each phase. Of 20 sequences of six fetuses scanned, 13 sequences successfully demonstrated usable 3D fetal heart structures, including four cardiac chambers, ventricular and atrial septa, foramen ovale and some of the cardiac valves and great vessels. Rearrangement of those phased 3D images into a cyclic sequence could generate dynamic 3D views of a beating fetal heart. We believe that, with further technical development, this new approach will be of use in the diagnosis of prenatal cardiac malformations and malfunctions, in in utero cardiac surgery and in fetal cardiology teaching.

1995 outlook.

Competition is transforming the healthcare marketplace, and providers are scrambling to emphasize their cost-effectiveness as well as their dedication to high quality. Modern Healthcare takes a look at what lies ahead in the varied sectors of the healthcare industry.

Three-dimensional imaging of the prostatic urethra--an exciting new tool.

OBJECTIVE: To evaluate the technique of three-dimensional (3-D) ultrasound imaging of the urethra and its application in both research and clinical practice. PATIENTS AND TECHNIQUE: The study involved 23 patients: 10 with benign prostatic hyperplasia, four with urethral strictures, three post-insertion of prostatic stents, one with bladder neck dyssynergia, three post-transurethral resection of the prostate, and two with non-urological conditions. A transrectal ultrasound scan was initially performed to acquire a series of images of the urethra. These images were then reconstructed into a 3-D format. RESULTS: The 3-D image of the urethra could be rotated on screen and viewed from any angle. The image could also be sliced at any plane to reveal the sectional view. CONCLUSION: This new tool represents a major advance in imaging techniques and promises to provide new knowledge in understanding the hydrodynamics of the lower urinary tract. The precise geometry of the 3-D urethra will also help in the design of new stents.

Three-dimensional US of the fetus. Work in progress.

PURPOSE: To develop a system for three-dimensional (3D) ultrasonography (US) that readily interfaces with conventional equipment and to apply this system to fetal imaging. MATERIALS AND METHODS: An acquisition system based on transputer technology records from the video output of standard clinical scanners was interfaced with a position-sensing device, one component of which was attached to the US probe. The method differs from other 3D US methods as any conventional probe may be used, freehand scanning is possible, and no line-of-sight limitations operate. Such scanning was performed of 25 fetuses with gestation ages of 7-30 weeks. RESULTS: Acquisition typically took 3-5 seconds. Acquisition and reconstruction were successful in 17 of 25 cases and were easiest to perform in the first and second trimester. Surface rendering revealed anatomic detail that was not depicted with two-dimensional scanning. CONCLUSION: The technique has the potential for recording complete anatomic studies for review and visualization of detail that is difficult to perceive on conventional US scans.

Three-dimensional computed tomography cholangiography: a new technique for biliary tract imaging.

Knowledge of the segmental anatomy and intersegmental biliary connections is an essential prerequisite to the effective management of patients with complex biliary strictures. Three dimensional (3D) imaging has the ability to demonstrate complex anatomical relationships that are difficult to appreciate on simple non-invasive two dimensional (2D) imaging. Our aim was to develop a technique for accurate, non-invasive 3D computed tomography (CT) cholangiography. Contiguous 4 mm CT sections were obtained through the liver during a dynamic bolus of 200 ml IV contrast. 3D surface reconstructions were then performed, the biliary system was isolated from surrounding hepatic parenchyma using segmentation and contrast threshold algorithms. 14 patients (six females, eight males, median age 68 years (range 48-82)) were studied. 13/14 had malignant biliary obstruction and one had obstruction secondary to a pancreatic pseudocyst. Obstruction was at the liver hilum in eight, the common bile duct in five and the common hepatic duct in one. Four patients had biliary endoprostheses but were symptomatic from inadequate drainage. There was good demonstration of the biliary anatomy, obstructed segments and intersegmental biliary connections in 13/14; irregular biliary dilatation secondary to primary sclerosing cholangitis rendered interpretation difficult in one. 3D cholangiography provided a useful adjunct to other imaging techniques. In particular, in patients with complex hilar strictures it aided implementation of appropriate interventional drainage procedures.

The appearance of normal and abnormal arterial morphology on intravascular ultrasound.

The ultrasonic appearance of in vitro normal and atherosclerotic arterial wall was investigated with an intravascular ultrasound (IVUS) probe. Fresh cadaver specimens were used: two carotid, two aorta, four iliac and eight superficial femoral arteries. The wall of muscular arteries has a three-layered sonographic appearance. The central hypoechoic layer corresponds to the media, which is primarily composed of smooth muscle. Elastic arteries whose media have a high elastin content appear uniformly echogenic. Calcified plaque is strongly echogenic with acoustic shadowing, fibrous plaque is moderately echogenic, and where there is no cellular matrix the plaque is poorly echogenic. IVUS can provide information about internal plaque architecture. Three-dimensional reconstructions can be generated using a transputer-based workstation coupled to the transducer, providing detailed views of surface contour.

3-dimensional reconstruction of ultrasound images of the uterine cavity.

We report our experience of 3-dimensional (3-D) reconstruction of ultrasound images of the uterine cavity. This is the first time that mapping of the contours of the uterine cavity with 3-D reconstruction has been achieved using standard clinical equipment for image acquisition. Ultrasound contrast hysterography was performed on 10 patients using both negative and positive intrauterine contrast media. 3-D image acquisition was performed during uterine cavity distension. The manipulation of the 3-D data sets is described and examples are shown. We believe that in some circumstances 3-D reconstructed images may be easier to interpret than 2-dimensional ultrasound images. We anticipate that this new technique will have a role in the preoperative assessment of uterine fibroids and endometrial polyps.

Three-dimensional visualization of data on human anatomy: diagnosis and surgical planning.

A system is described which produces displays of anatomical surfaces from sets of X-ray computed tomography (CT), magnetic resonance imaging (MRI) and ultrasonographic scans (US). The displays are created to show the three-dimensional character of the internal and external anatomy. The images may be manipulated on the screen to simulate dissection of the three-dimensional object they represent. Thus it is possible to increase the diagnostic value of the original data and to plan surgery by simulation. To allow long-term studies on the human face for surgical planning and assessment a non-hazardous optical scanning system has been devised. The display system also produces data to drive a numerically controlled milling machine for the production of models, prostheses and implants.

A new method of haemodynamic assessment of mitral stenosis in atrial fibrillation: construction of a nomogram.

Accurate haemodynamic assessment of mitral stenosis by hydraulic formulas requires measurement of the mean valve gradient and the cardiac output. The calculation is laborious, particularly in the presence of atrial fibrillation when averaged values obtained from multiple beat-to-beat determinations must be used. The relations between valve area, end diastolic gradient, and heart rate in 20 patients with mitral stenosis and atrial fibrillation were examined. In each patient the end diastolic pressure gradient for each cardiac cycle was related linearly to the RR interval of that cycle, and this relation was unchanged on exercise. The slope (S) and intercept (I) of this relation correlated with the degree of mitral stenosis as measured by the Gorlin valve area. The regression equations describing these relations were then used to construct a nomogram relating end diastolic pressure gradient to mitral valve area at different heart rates. When the nomogram was applied to catheterisation data from a further 30 patients the results correlated well with direct calculation of valve area by the Gorlin formula. The nomogram is simple to use, does not require measurement of cardiac output, and is independent of heart rate so that it is unnecessary for the patient to exercise during catheterisation.

Protective effect of collateral vessels during coronary angioplasty.

To assess the potential protective role of collateral vessels 27 patients undergoing angioplasty of the left anterior descending coronary artery were studied by intravenous digital subtraction left ventriculography. Fifteen patients had no collateral vessels (group 1) and 12 had some degree of collateral supply (group 2). During balloon inflation ST segment elevation in group 1 (4.9 mm) was significantly greater than that in group 2 (0.9 mm). Similarly the reduction in left ventricular ejection fraction was significantly greater in group 1 (24%) than in group 2 (12%). Both the size of ST segment elevation and the fall in ejection fraction correlated inversely with the extent of the collateral supply (r = -0.680 and r = -0.446 respectively). During balloon occlusion of the anterior descending coronary artery the percentage shortening of the anterior and apical segments fell in both groups but apical shortening fell to a lesser extent in group 2. An additional reduction in anterobasal contraction was confined to group 1. Electrocardiographic and ventriculographic manifestations of ischaemia produced by balloon inflation during angioplasty are less pronounced when collateral vessels are present. This suggests that the collateral circulation can protect myocardium at risk of ischaemia after coronary occlusion.

Phase and amplitude analysis of exercise digital left ventriculograms in patients with coronary disease.

Phase and amplitude analysis was applied to intravenous digital left ventriculograms to avoid the artefacts associated with image subtraction. Eight controls and 40 patients with known coronary artery disease underwent digital left ventriculography before and after a symptom limited supine bicycle exercise test. The resultant images were subjected to phase and amplitude analyses. In the control group there was no deterioration in left ventricular wall motion after exercise. In 30 of the 40 patients there was a deterioration in wall motion on exercise. This group contained all eight patients with three vessel disease and 12 of the 17 patients with two vessel disease. Ten patients showed no change in wall motion--five with one vessel disease and five with two vessel disease. Phase and amplitude analysis of digital left ventriculograms is a method of detecting exercise induced myocardial ischaemia that may help in the assessment of patients with coronary artery disease.

Significance of "reciprocal" ST segment depression: left ventriculographic observations during left anterior descending coronary angioplasty.

To evaluate the significance of "reciprocal" ST segment depression resulting from coronary occlusion, 27 patients with single vessel coronary disease were studied with intravenous digital subtraction left ventriculography before and during angioplasty of the left anterior descending coronary artery. During balloon inflation, 13 patients developed inferior lead ST depression in addition to anterior lead ST elevation (Group 1), whereas the remaining 14 patients did not (Group 2). The degree of anterior lead ST elevation in Group 1 (5 mm) was greater than that in Group 2 (1.5 mm, p less than 0.001) as was the reduction in left ventricular ejection fraction (24% versus 13%, respectively; p less than 0.02). Anterior and apical regional shortening decreased in both groups similarly, but an additional decrease in anterobasal shortening was confined to Group 1 (from 38% to 21%; p less than 0.002). Despite the presence of inferior lead ST depression in Group 1, inferior regional shortening did not change and inferobasal contraction was enhanced (from 4% to 29%; p less than 0.01). Inferior lead ST segment depression during anterior descending coronary angioplasty reflects a greater degree of anterior wall ischemia. The concurrent preservation of inferior wall contraction and the augmentation of infero-basal shortening confirm that this electrocardiographic feature is a "reciprocal" phenomenon rather than a manifestation of remote ischemia.

Assessment of left ventricular performance during percutaneous transluminal coronary angioplasty: a study by intravenous digital subtraction ventriculography.

Left ventricular performance during percutaneous transluminal coronary angioplasty was assessed in 52 patients by intravenous digital subtraction ventriculography. After injection of contrast into the right atrium ventriculograms were obtained before and during balloon inflation. In 37 patients they were also obtained after the procedure. A 12 lead electrocardiogram was monitored throughout. During balloon inflation the left ventricular ejection fraction fell (from 73% to 57%) in all but one patient; the decreases in patients with single vessel or multivessel disease were similar. The fall in left ventricular ejection fraction during percutaneous transluminal coronary angioplasty of the left anterior descending artery (19%) was significantly greater than that during balloon inflation in the right coronary (10%) or circumflex (8%) coronary arteries. It also reduced anterobasal, anterior, and apical segmental shortening while right coronary percutaneous transluminal coronary angioplasty affected inferior and apical segments. In 33 (63%) patients the ST segment was altered during balloon inflation. The fall in left ventricular ejection fraction correlated significantly with the magnitude of both ST segment elevation (r = 0.637) and ST depression (r = 0.396). Left ventricular ejection fraction and regional wall motion returned to baseline values after the procedure. Balloon inflation during percutaneous transluminal coronary angioplasty produces considerable abnormalities of global and regional left ventricular performance and this indicates the presence of myocardial ischaemia, which may not be apparent on electrocardiographic monitoring. Intravenous digital subtraction ventriculography is useful for monitoring left ventricular performance during controlled episodes of coronary occlusion produced by balloon inflation.

Arrival-time analysis of intravenous digital aortograms in aortic dissection.

Arrival-time analysis was applied to intravenous digital aortograms. A single static image was produced by representing the time to 90% maximum density for each image pixel on a grey scale. Arrival-time analysis confirmed the diagnosis in four of six patients with aortic dissection that had been shown by image subtraction. In a further three patients with no dissection the arrival-time images were normal. In two patients with surgical repair of the ascending aorta, residual false lumens were shown by both subtraction and arrival-time analysis. In one of these cases arrival-time analysis prompted reanalysis of the subtraction image that had previously been interpreted as showing a normal aorta. Arrival-time analysis provides a static image of aortic dissection, which helps to overcome subtraction artefact.