Background. The clinical effects of percutaneous transluminal renal artery angioplasty (PTRA) in patients with renal vascular stenosis and hypertension is controversial. Methods. We consecutively recruited all 23 patients referred for evaluation of renovascular hypertension that eventually underwent unilateral PTRA, to be investigated with captopril MAG3 renography (CR), both before and after the endovascular procedure. Data were evaluated on an intention-to-treat basis. Results. We found that the relative MAG3 clearance of the stenotic kidney increased (from 29.9 ± 14% to 35.1 ± 14%, p=0.01) and that the creatinine levels fell following the intervention (from 110 ± 19 to 99 ± 17 μmol/l, p=0.0003). Blood pressure levels were also lowered (from 173 ± 32/93 ± 17 to 158 ± 31/86 ± 15 mmHg, p<0.006) while the mean number of anti-hypertensive drugs was unchanged following PTRA (2.9 ± 1.4 before and 2.8 ± 1.3 drugs after the intervention, respectively, p-0.6). Conclusion. This prospective trial showed statistically significant improvements of individual kidney function as measured by CR and blood pressure in subjects with suspected renovascular hypertension treated with PTRA. Although the endovascular procedure was found to be safe, the magniture of the absolute improvements was rather modest. © 2005 Taylor & Francis.
Background: Rectal administration of enemas, foams and suppositories is the most efficient way to deliver locally acting drugs to the distal colon. Ropivacaine, a long-acting local anaesthetic, was chosen as a candidate for a new rectal treatment of ulcerative colitis. Aim: To determine the colonic spread of a rectal ropivacaine formulation. Methods: In this randomized, incomplete cross-over study, 12 male volunteers were given 200 mg ropivacaine HCl rectally in 20, 40, 60 and 80 mL hydroxypropyl methylcellulose gel. The viscosity of the gel was 1.1 Pa s. The spread of the radiolabelled ( 99mTc-labelled diethylenetriaminepenta-acetic acid) formulations was assessed by gamma-scintigraphy. Plasma was collected and analysed for ropivacaine base. Results: The retrograde spread was limited to the descending colon and the difference between the studied volumes was not statistically significant. Only the 80-mL volume tended to have a larger distribution, although the 20-mL volume showed the same maximal distribution in two subjects. No distinct relationship between volume, retrograde colonic spread and plasma concentrations could be found. Ropivacaine was well tolerated. Conclusions: Rectal ropivacaine gel in all volumes between 20 and 80 mL can spread up to the descending colon. There was no relationship between either retrograde colonic spread or the administered volume and the ropivacaine plasma concentrations.
Att utvärdera det vetenskapliga underlaget för olika åtgärder mot fetma hos vuxna och barn. Underlaget för såväl förebyggande åtgärder som olika behandlingsformer granskats. Bland behandlingsmetoderna ingår kost/diet, motion, beteendeterapi, läkemedel, alternativmedicinska och kirurgiska metoder.
Randomised controlled trials have shown that the policy of mammographic screening confers a substantial and significant reduction in breast cancer mortality. This has often been accompanied, however, by an increase in breast cancer incidence, particularly during the early years of a screening programme, which has led to concerns about overdiagnosis, that is to say, the diagnosis of disease that, if left undetected and therefore untreated, would not become symptomatic. We used incidence data from two randomised controlled trials of mammographic screening, the Swedish Two-county Trial and the Gothenburg Trial, to establish the timing and magnitude of any excess incidence of invasive disease and ductal carcinoma in situ (DCIS) in the study groups, to ascertain whether the excess incidence of DCIS reported early in a screening trial is balanced by a later deficit in invasive disease and provide explicit estimates of the rate of 'real' and non-progressive 'overdiagnosed' tumours from the study groups of the trials. We used a multistate model for overdiagnosis and used Markov Chain Monte Carlo methods to estimate the parameters. After taking into account the effect of lead time, we estimated that less than 5% of cases diagnosed at prevalence screen and less than 1 % of cases diagnosed at incidence screens are being overdiagnosed. Overall, we estimate overdiagnosis to be around 1 % of all cases diagnosed in screened populations. These estimates are, however, subject to considerable uncertainty. Our results suggest that overdiagnosis in mammography screening is a minor phenomenon, but further studies with very large numbers are required for more precise estimation. © 2005 BioMed Central Ltd.
We aimed to quantify the benefits of detecting ductal carcinoma in situ (DCIS) and of downwards stage-shifting within invasive tumours in mammographic screening. Using data from the Swedish Two-County Trial of breast cancer screening, we examined the 20-year death rates from invasive tumours of stage II or worse, invasive tumours of stage I and DCIS. We then used these rates and their respective incidences in invited (active study population, ASP) and control (passive study population, PSP) arms of the trial, to estimate the numbers of deaths avoided by downward stage-shifting the larger stage II or worse tumours to stage I and the stage I cancers to DCIS. We also studied the association between the mortality reduction achieved and the proportion of DCIS cases detected in the randomised trials of breast cancer screening. In the Swedish Two County Trial, 141 breast cancer deaths were avoided in the ASP compared with the PSP at approximately 20 years of follow-up. Of these, 65% (91/141) were avoided as a result of stage-shifting from invasive stage II or worse to invasive stage I, and 5% (7/141) as a result of stage-shifting from invasive stage I to DCIS. If we assumed that 10% of stage II or worse tumours avoided were shifted not to stage I, but to DCIS, the estimated number of deaths prevented by shifting from invasive disease to in situ was 17, which is 12% of all deaths prevented. When the results of all the randomised trials of breast cancer screening were reviewed, there was no clear association between the percentage of DCIS cases diagnosed and the observed mortality reduction. We conclude that compared with downward stage-shifting of invasive tumours, detection of DCIS plays a small part in saving lives from breast cancer. Treatment decisions in DCIS, as in invasive carcinoma, should take full account of histopathological, clinical and radiological attributes of the tumour. ⌐ 2003 Elsevier Ltd. All rights reserved.
In some limited-resource areas, a state-of-the-art mammography program is not affordable. In such circumstances, one might consider a less resource-intensive, but also less sensitive screening tool such as clinical breast examination (CBE). We used data from the Swedish Two-County Trial to estimate the shift in tumor size resulting from invitation to mammographic screening. By postulating a lesser benefit of a less sensitive screening tool (CBE), particularly in terms of detecting very small tumors, we predicted its likely effect on tumor size distribution. In addition, using the observed association between tumor size and nodal status, and between tumor size and fatality, we predicted the likely benefit in terms of reductions in node-positive disease and in breast cancer mortality. An invitation to mammographic screening was associated with a 27% reduction in the number of node-positive tumors and a 31% reduction in the number of breast cancer deaths. We estimate that in the trial population, screening with CBE alone would have led to an 11% reduction in node-positive tumors and an 11% reduction in breast cancer deaths (approximately 42 deaths prevented per 1000 cases). Assuming instead a tumor size distribution typical of a limited-resource setting (70% of tumors are 30 mm at presentation), we estimate that screening with CBE alone would lead to a 13% reduction in node-positive tumors and a 12% reduction in breast cancer deaths (approximately 72 deaths prevented per 1000 cases). Thus, although the relative benefit of CBE is only slightly greater in the limited-resource setting, the absolute reduction in deaths per case is about 70% higher. Our findings suggest that a less sensitive tool might be expected to confer a breast cancer mortality reduction about half of that observed with mammography. © 2006 The Fred Hutchinson Cancer Research Center.
Background: The Swedish Two-County Trial has been criticised on the grounds of the cluster randomisation and alleged bias in classification of cause of death. Patients and methods: In the Two-County Trial, 77080 women were randomised to regular invitation to screening (active study population, ASP) and 55985 to no invitation (passive study population, PSP), in 45 geographical clusters. After ~7 years, the PSP was invited to screening and the trial closed. We analysed data using hierarchical statistical models to take account of cluster randomisation, and performed a conservative analysis assuming a systematic difference between ASP and PSP in baseline breast cancer mortality in one of the counties. We also analysed deaths from causes other than breast cancer and from all causes among breast cancer cases diagnosed in the ASP and PSP. Results: Taking account of the cluster randomisation there was a significant 30% reduction in breast cancer mortality in the ASP. Conservatively, assuming a systematic difference between ASP and PSP clusters in baseline breast cancer mortality, there was a significant 27% reduction in mortality in the ASP. Ignoring classification of cause of death, there was a significant 13% reduction in all-cause mortality in breast cancer cases in the ASP. Conclusions: Breast cancer mortality is a valid end point and mammographic screening does indeed reduce mortality from breast cancer. The criticisms of the Swedish Two-County Trial are unfounded.
A fast and simple method for three-dimensional shape description is described. The method views a 3D object as a radial distance function on the unit sphere, and thus reduces the dimensionality of the description problem by one. The radial distance function is approximated by Fourier methods in the basis of the spherical harmonic polynomials. The necessary integration is carried out on the object boundary, rather than on the unit sphere. Consequently, there is no need of a parameterisation of the object surface. The description makes it possible to compare shapes in a computationally very simple way. Solutions on how to cope with translated and rotated objects are discussed. The method is developed for star-shaped objects, but is stable even if the input image is non-star-shaped. The method is tested in a data set from magnetic resonance imaging (MRI) of the brain. Potential medical applications are discussed. ⌐ 2002 Elsevier Science Ireland Ltd. All rights reserved.
Depth perception is a common problem for x-ray vision in augmented reality applications since the goal is to visualize occluded and embedded objects. In this paper we present an x-ray vision blending method for neurosurgical applications that intensifies the interposition depth cue in order to achieve enhanced depth perception. The proposed technique emphasizes important structures, which provides the user with an improved depth context.
PURPOSE: To retrospectively investigate whether different review designs have an influence on the estimate of missed interval cancer in a population-based breast cancer screening program. MATERIALS AND METHODS: The Norwegian Breast Cancer Screening Program invites women aged 50-69 years to undergo biennial screening mammography. The current study was part of the evaluation and scientific aspects of the screening program and thus was covered by the general ethical approval of the screening program as a part of the Cancer Registry of Norway. All participants signed an informed consent that specified that data related to their screening visit could be used for evaluation and scientific purposes. Six radiologists (9-34 years of experience in mammography) reviewed previously obtained bilateral two-view screening and diagnostic mammograms of 231 interval cancers, 117 screening-detected cancers, and 373 normal cases. Four review designs were used: individual and paired blinded review and individual and consensus informed review. A five-point interpretation scale was used to reclassify the cancers into missed cancers, minimal signs, and true cancers. The number and proportion of subgroups were estimated with 95% confidence intervals. RESULTS: Of 231 interval cancers, 46 (19.9%) were reclassified as missed cancers with the mixed blinded individual review and 54 (23.4%) were classified as missed cancers with the mixed blinded paired review. Eighty-three cancers (35.9%) were classified as missed cancers with individual informed review, and 78 (33.8%) were classified as missed cancers with consensus informed review. Thirty-nine cancers (16.8%) were reclassified as missed when four or more radiologists assigned a score of 2 or more (probably benign or more suspicious), three cancers (1.3%) were reclassified as missed when a score of 4 or more (probably malignant or more suspicious) was assigned. CONCLUSION: The percentage of interval cancers classified as missed ranged from 1.3% to 35.9% according to review design. To encourage learning, a review protocol should include both blinded and informed designs. © RSNA, 2005.
Partly based on magnetic resonance imaging studies, the "plumb-bob" approach for brachial plexus block was designed to minimize the risk of pneumothorax. Nevertheless, the risk of pneumothorax has remained a concern. We analyzed magnetic resonance images from 10 volunteers to determine whether the risk of pneumothorax was decreased with this method. The recommended initial needle direction is anteroposterior through the junction between the lateral-most part of the sternocleidomastoid muscle and the superior edge of the clavicle. If the initial placement is not successful, the brachial plexus may be sought in sectors 20░-30░ cephalad or caudad to the anteroposterior line in a sagittal plane through the insertion point. We found that the anteroposterior line reached the pleura in 6 of 10 volunteers without prior contact with the subclavian artery or the brachial plexus, but always with contact with the subclavian vein. To reach the middle of the brachial plexus, a mean cephalad redirection of the simulated needle by 21░ was required (range from 41░ cephalad to 15░ caudad in one case). We conclude that the risk of contacting the pleura and the subclavian vessels may be reduced by initially directing the needle 45░ cephalad instead of anteroposterior. If the brachial plexus is not contacted, the angle should be gradually reduced.
Background: There is an unsettled discussion about whether the distribution of local anesthetic is free or inhibited when performing brachial plexus blocks. This is the first study to use magnetic resonance imaging (MRI) to help answer this question. Methods: Thirteen patients received axillary block by a catheter-nerve stimulator technique. After locating the median nerve, a total dose of 50 ml local anesthetic was injected via the catheter in four divided doses of 1, 4, 15, and 30 ml. Results of sensory and motor testing were compared with the spread of local anesthetic as seen by MRI scans taken after each dose. The distribution of local anesthetic was described with reference to a 20-mm diameter circle around the artery. Results: Thirty minutes after the last dose, only two patients demonstrated analgesia or anesthesia in the areas of the radial, median, and ulnar nerve. At that time, eight of the patients had incomplete spread of local anesthetic around the artery, as seen by MRI. Their blocks were significantly poorer than those of the five patients with complete filling of the circle, although incomplete blocks were also present in the latter group. Conclusion: This study demonstrated that MRI is useful in examining local anesthetic distribution in axillary blocks because it can show the correlation between MRI distribution pattern and clinical effect. The cross-sectional spread of fluid around the brachial-axillary artery was often incomplete-inhibited, and the clinical effect often inadequate.
In the supraclavicular lateral paravascular approach for brachial plexus regional anesthesia by Moorthy et al. (Moorthy's block), the patient is supine with the ipsilateral shoulder displaced anteriorly 5-8 cm. The needle direction is precisely defined in the coronal plane (using a Doppler flowprobe) but not in the sagittal plane. We sought to determine whether the block could be simplified by keeping the shoulder in a neutral position, if the needle direction in the sagittal plane could be more precisely described, and if the risk of pneumothorax appeared acceptably small. These questions were studied by magnetic resonance imaging in 10 volunteers. Volume datasets of the periclavicular region allowed precise positioning of simulated needles. In all volunteers, Moorthy's block could be performed with the shoulder in a neutral position. The optimal needle trajectory passed 5 mm posterior to the clavicle and was 25░ posterior to the coronal plane, never approaching the pleura closer than 18 mm. We conclude that Moorthy's block can be performed with the shoulder in a neutral position, that more precise instructions for the needle direction can be given, and that the risk of pneumothorax seems minimal. This should be confirmed by a clinical study.
A case of Kleine-Levin syndrome with typical periodic hypersomnia and bulemia was diagnosed. On examination with single photo emission tomography (SPECT) (CERETEC«) during a relapse period and 2 weeks later there was marked cortical hypoperfusion of the frontal and temporal lobes, especially on the left side as well as in the right parietal lobe. Neuropsychological testing performed 1 week after a relapse showed a reduction in encoding to memory function of verbal learning indicating neocortical damage of the left fronto-temporal region. A follow-up 2 months later after the patient had spontaneously recovered showed only a slight left fronto-temporal disturbance. CT and MRI of the brain were normal although the MRI showed a large and asymmetric mamillary body. Neuropsychological testing 6 years after recovery showed pronounced reduction in short-time verbal and visual memory. Seven years after recovery SPECT demonstrated a normalized frontal perfusion but still a slight hypoperfusion in the left temporal lobe. Our results correlate to autopsy findings in two cases described previously.
Background - A previous investigation at our department of a young man with typical Kleine-Levin syndrome revealed short-term memory dysfunction as well as hypoperfusion of the temporal lobes on single photon emission tomography (SPECT) (CERETECR) examination, 6 and 7 years after recovery, suggesting long lasting or even permanent cerebral dysfunction. Patients and methods - We investigated four cases with classical adolescent Kleine-Levin syndrome characterized by hypersomnia and typical associated symptoms. We used neuropsychological testing and SPECT (CERETECR) of the brain. The results from the previous report related to above is included. Results - Examination with SPECT (CERETECR) during remission revealed hypoperfusion of the temporal lobes and fronto-temporal region in two of four cases. There were normal findings in two. Neuropsychological testing performed during remission showed reduction in the short-term memory capacity in all four cases. Conclusion - It is striking that all the cases investigated showed short-term memory dysfunction. One patient who had recovered from paroxysmal symptoms (hypersomnia attacks and bulimia) 6 years earlier showed progress in the short-term memory dysfunction. A pathologic condition in the temporal lobes may be suspected in Kleine-Levin syndrome.
This paper presents state-of-the-art methods, which address the technical challenges in visualizing large three-dimensional (3D) data and enable rendering at interactive frame rates.
The ever increasing size and complexity of volumetric data in a wide range of disciplines makes it useful to augment volume visualization tools with alternative modalities. Studies have shown that introducing haptics can significantly increase both exploration speed and precision. It is also capable of conveying material properties of data and thus has great potential to improve user performance in volume data exploration. In this paper we describe how recent advances in volume haptics can be used to build haptic modes-building blocks for haptic schemes. These modes have been used as base components of a toolkit allowing for more efficient development of haptic prototypes and applications. This toolkit allows interactive construction, configuration and fine-tuning of both visual and haptic representations of the data. The technology is also used in a pilot study to determine the most important issues and aspects in haptic volume data interaction and exploration, and how the use of haptic modes can facilitate the implementation of effective haptic schemes.
Aims. To investigate whether hyperechogenicity of liver can reliably be interpreted as liver steatosis and if any concomitant or isolated fibrosis can be disclosed. Patients and methods. A series of 165 patients with no signs or symptoms of liver disease referred because of slightly to moderately raised aminotransferases (alanine aminotransferase and/or aspartate aminotransferase 0.7-5.0 ╡kat/l) for more than 6 months were prospectively investigated with a comprehensive laboratory profile, ultrasound examination of liver and percutaneous liver biopsy. Fibrosis was assessed quantitatively and according to Metavir. Steatosis was graded as none, mild, moderate or severe. Results. Of 98 (59.4%) patients with raised echogenicity, 85 (86.7%) had liver steatosis of at least moderate degree, 9 patients with same degree of steatosis had normal echogenicity and 13 patients with no or only mild steatosis had normal echogenicity liver (sensitivity 0.90, specificity 0.82, positive predictive value 0.87, negative predictive value 0.87). About the same relations were found regardless of body mass index and degree of fibrosis. With increased echogenicity together with high attenuation (n=59) and reduced portal vessel wall distinction (n=79), positive predictive value increased to 0.93 and 0.94, respectively. Quantitatively assessed fibrosis (mean ▒ SD) was 3.2▒4.6% of biopsy area with normal and 2.3▒1.8% with raised echogenicity [ns]. Echogenicity was normal in 5 out of 9 patients with septal fibrosis and in 4 out of 6 patients with cirrhosis. Any structural, non-homogenous findings at ultrasound were not associated with architectural fibrotic changes and none had nodular contours of liver surface. Conclusions. Assessment of liver echogenicity is of value for detection or exclusion of moderate to pronounced fatty infiltration (correct classification 86.6%) but cannot be relied upon in diagnosing fibrosis, not even cirrhosis in asymptomatic patients with mild to moderately elevated liver transaminases.
Purpose. To study the use of a combination of a clinical and scintigraphic protocol in relation to the final outcome diagnosis in patients with clinical suspicion of acute pulmonary embolism (PE). Material and methods. A total of 170 patients with clinical suspicion of acute PE were all examined with ECG, blood chemistry, chest X-ray, pulmonary scintigraphy and selective pulmonary arteriography. The scintigraphic and clinical probabilities of PE were estimated on visual analogue scales (VASs) by different readers unaware of each others' results. The follow-up time was 6 months. In order to establish the final diagnosis a final outcome committee was created. They analysed in retrospect all the clinical and laboratory data and established whether the patient had had PE or not. Results. The final outcome committee concluded that 53 patients had PE. When the scintigraphic and clinical probability judgements were congruent, a combined probability of 1-25% (i.e low probability) had a negative predictive value of 98%. When the combined probability was 26-75% (i.e. intermediate) half of the cases had PE. With a combined probability of 76-100% (i.e. high) the positive predictive value was 100%. Conclusion. By applying a model of combined clinical and scintigraphic probabilities for PE, the diagnosis is ruled in when the combined probability is high, and ruled out when the combined probability is low. However, nearly half of the patients will still have an uncertain diagnosis for which further diagnostic procedures may be allocated.
Phosphorus-31 NMR spectroscopy using slice selection (DRESS) was used to investigate the absolute concentrations of metabolites in the human liver. Absolute concentrations provide more specific biochemical information compared to spectrum integral ratios. Nine patients with histopathologically proven diffuse liver disease and 12 healthy individuals were examined in a 1.5-T MR scanner (GE Signa LX Echospeed plus). The metabolite concentration quantification procedures included: (1) determination of optimal depth for the in vivo measurements, (2) mapping the detection coil characteristics, (3) calculation of selected slice and liver volume ratios using simple segmentation procedures and (4) spectral analysis in the time domain. The patients had significantly lower concentrations of phosphodiesters (PDE), 6.3±3.9 mM, and ATP-β, 3.6±1.1 mM, (P<0.05) compared with the control group (10.0±4.2 mM and 4.2±0.3 mM, respectively). The concentrations of phosphomonoesters (PME) were higher in the patient group, although this was not significant. Constructing an anabolic charge (AC) based on absolute concentrations, [PME]/([PME] + [PDE]), the patients had a significantly larger AC than the control subjects, 0.29 vs. 0.16 (P<0.005). Absolute concentration measurements of phosphorus metabolites in the liver are feasible using a slice selective sequence, and the technique demonstrates significant differences between patients and healthy subjects.