PurposeThe aim of this study is determination of the effective filters for myocardial perfusion studies. Material and methodsTwenty-eight patients have been investigated using a standard stress–rest 2-day protocol. The data acquired were processed using a METZ filter (PSF FWHM 4, order 8) and reprocessed in Butterworth (order 4, cut-off 25) filters (8 frames per cycle). LV volumes were calculated using standard Multidim software. Patients also underwent MR perfusion studies. Stress and rest images were analysed using standard perfusion score. ResultsComparison of acquired data processed in different filters show that there is no significant difference in LV EF (48.9 and 46.9, P<0.001). Nevertheless, EDV and ESV are higher using the METZ filter than when data are processed in the Butterworth filter. LV EF acquired by MRI show slightly higher EF results than data from gated SPECT (mean EF MRI 55.08 compared to METZ 44.8, P<0.01). EDV determined from 2 filters showed larger difference in ESV, but correlation with MRI was poor. Perfusion score which was determined in bull's eye format acquired from BTRW filter was less than from METZ filter (22.25 and 17.15, respectively; P<0.001). There was good correlation between delayed early perfusion on MRI and stress induced ischaemia on SPECT on subjective analysis. ConclusionThe type of filter used in perfusion scan analysis has a clear effect on calculated parameters and overall clinical impression of the scan. An internal standardization of filter is recommended.

In a prospective study, a radionuclide technique was used to evaluate the limb blood flow (LBF) changes in 30 patients undergoing dynamic (n=15) or balloon (n=15) angioplasty for arterial occlusions or stenoses, respectively. The results were compared with Doppler Ankle Brachial Index (DABI) and treadmill exercise tests. Whilst LBF values (ml of blood flow per 100 ml of limb volume per min) were significantly lower in limbs with arterial occlusion than stenosis (4.5±0.46 and 6.4±0.74, respectively; P<0.05), DABI provided no discrimination. Immediately after balloon angioplasty, there was a fall in DABI, from 0.60±0.05 to 0.47±0.04 (P<0.05), which rose 24 h later to 0.73±0.02 (P<0.01). Following dynamic angioplasty, DABI improved from 0.60±0.05 to 0.66±0.02 (P<0.05). At 3 weeks, the LBF improved from 4.6±0.66 to 11.1±0.53 (P<0.001) following dynamic angioplasty and from 6.2±0.68 to 8.53±0.81 (P<0.001) following balloon angioplasty. “Normal” LBF (> 10 ml/100 ml per min) was achieved in 80% of patients who underwent successful dynamic angioplasty but in only 36% of the balloon group (P<0.05, χ2-test). Reproducibility of repeated LBF measurements in control limbs was superior to that of DABI. This was indicated by a lower coefficient of variation, 13.8% compared with 25.2%, and a higher correlation coefficient, r=0.79 compared with 0.27. Treadmill exercise tests were invalid or impossible in 30% of all occasions. There was a good correlation between the improvement in maximum walking distance on the treadmill and that in LBF (r=0.84, P<0.05). In conclusion, measurement of LBF using radionuclide technique is a potentially valuable method for the assessment of patients undergoing percutaneous angioplasty. LBF results are reproducible and correlate well with the improvement in walking ability, which cannot always be assessed objectively.

PurposeMRI and nuclear cardiac imaging have broad clinical applications for diagnosis and evaluation of cardiac disorders. Until recently, detection of chronic myocardial infarction using MRI was determined by thinning of the left ventricular wall and abnormal segmental wall motion on cine MRI and a non-perfused defect on SPECT imaging. We evaluated a new pulse sequence using gadolinium injection to detect scar formation on MRI and compared this to SPECT myocardial imaging. Materials and methodsUsing a segmented inversion recovery gradient echo pulse, we studied 10 patients using contrast enhanced MRI (CEMRI) who presented with chest pain. With this method chronically infarcted myocardium appears white against black normal myocardium. We used this method to distinguish non-transmural MI from transmural MI, and to detect multiple chronic infarction in different segments. Images were obtained in short-axis and long-axis projections. Nuclear perfusion imaging was analysed on the same patients on a segmental basis. Infarcted segments were also directly compared to coronary arterial stenoses at catheterization. ResultsInfarcted segments were sharply demarcated, permitting measurement of infarct mass. Infarcted mass was determined by subtraction of the non-infarcted segments from total LV mass. Concordance with nuclear imaging was found in 127 segments and discordance in 33 segments. Small infarcts were clearly demonstrated on MRI. ConclusionCEMRI has important application to detect and evaluate the significance of chronic myocardial infarction. Infarcted segments can be compared directly to cardiac catheterization and may yield important information on myocardial viability.

It is imperative that cancer care management protocols are established rapidly to help assess, prepare and instigate the required treatment procedures. We have addressed one such requirement i.e. in the management of lung cancer care using digital systems integration and telemedicine. With the telemedical system in place 160 patients have been imaged by the Digital Radiography (DR) system and the images have been transferred simultaneously on to the viewing systems for radiology and surgical opinions. The images acquired and transmitted digitally comprise a patient group where around 80% of the patients have had cancer, needing surgical intervention; the images were both pre and post operative images.

Abstract Background In 1999 an emergency vascular service for Bristol and Avon (including Weston-Super-Mare) (population approximately 1 million) was initiated. Methods Collaboration between Bristol Royal Infirmary, Frenchay and Southmead Hospitals provides week-on–week-off vascular cover for patients requiring urgent and emergency interventions within 24 h. The rota accommodates National Confidential Enquiry into Perioperative Deaths and Vascular Surgical Society of Great Britain and Ireland recommendations, governance issues, and enhances emergency vascular care for Avon residents. Prospectively collected data for the first year (May 1999 to April 2000) are reviewed. Results There were 289 emergency admissions. (In-hospital referrals were not transferred but contributed up to 40 per cent of the extra emergency workload per unit.) Referrals were also accepted from seven Trusts outside the designated catchment area. Caseload included 86 patients with a ruptured or acutely symptomatic aortic aneurysm, of whom 69 underwent operation (30 per cent mortality rate); 17 patients were not operated on. Some 136 patients had critical leg ischaemia (43 acute, 93 chronic); angiography or duplex ultrasonography was performed in 105 cases (77 per cent); 39 patients (29 per cent) had undergone previous intervention for peripheral vascular disease; the mortality rate was 18 (13 per cent) of 136; 18 (13 per cent) of 136 patients required an amputation. Other cases included: upper limb ischaemia, 20 (7 per cent); paediatric emergency, seven (2 per cent); symptomatic carotid disease, five (2 per cent; four endarterectomies with no death or stroke). Some 5 per cent of referrals were inappropriate (venous ulcer, spinal stenosis, etc.). No outcomes were compromised by interhospital transfers. Vascular surgeons operated on nine high-risk patients away from their ‘base’ hospital. A consultant was the principal or assistant operator in more than 95 per cent of operations but, despite trainee rota adjustments, a designated vascular trainee was present in only about 40 per cent of cases. Conclusion Interhospital provision of emergency vascular services for a large population is feasible, does not compromise quality of care, and regulates emergency workload. Further attention to training issues is indicated.

In this paper, wavelet image compression algorithm has been applied to the different modules of medical images, the angiography of the coronary vessels, Barium FT, Ultrasound of the gall bladder, MR Brain, CT Scan, Pulmonary Angiography, and X-ray of the Hand. The FFT frequency domain contains the texture properties of the image. The correlation coefficient of picture textures for original and compressed images is defined as picture textural quality scale (PTQS). Histogram of the picture shows the contrast information of the images. The correlation coefficient of picture histograms for original and compressed images is defined as picture histogram quality scale (PHQS). The PTQS and PHQS of different medical images and image quality on compression ratio are studied. The result shows that PTQS can be used widely as the threshold of medical image compression.

This study aimed at assessing the value of Tl-201 scans to detect restenosis following coronary stent implantation. Of 47 patients who had a coronary stent implantation, 38 with 44 stent implants underwent stress perfusion imaging and repeat coronary angiography 3 months after the procedure. The angiographic restenosis rate was 31.8%. A perfusion defect on stress image which showed redistribution at rest was considered a positive scan. Thallium scans were found to have a sensitivity of 71% and a specificity of 93.3%. A non-reperfusing defect was observed in all false-negative studies. Normal myocardial perfusion always co-existed with the patent stents, with no significant luminal compromise. An unimpaired perfusion on scan strongly suggested adequate patency of the stented arterial segment.

To evaluate the results of percutaneous transluminal angioplasty (PTA) of the tibial vessels, results of 50 procedures performed in 38 patients since 1988 were analysed retrospectively. A total of 73 tibial vessels were treated: 32 anterior tibial arteries, 16 posterior tibial arteries, four peroneal arteries, 12 tibioperoneal trunks and nine trifurcation lesions. Forty-four of 50 PTA procedures were performed in conjunction with interventions in the femoropopliteal arteries and six as isolated procedures. One patient required a femorodistal graft following perforation of the popliteal artery during atherectomy. Distal emboli occurred in two patients and acute thrombosis of both the angioplastied tibial vessels occurred in a third. The technical success rate was 96 per cent. Patients were followed for a mean(s.d.) of 21(13) months. At the latest follow-up, 58 per cent had improved clinically. There were significant improvements in 43 per cent of limb isotope blood flow studies and 52 per cent of ankle:brachial Doppler pressure indices in treated limbs at this time. PTA should be the first treatment option in patients with infrapopliteal arterial disease needing intervention, whenever it is technically feasible.

An isotope limb blood flow technique was used to assess the outcome of technically successful balloon angioplasty. Measurements were made on a total of 120 limbs, before angioplasty and at least once after angioplasty at 3 weeks, 3 months, 6 months, 12 months and 2-5 years. 67% of treated limbs showed a significant improvement in limb blood flow at 3 weeks. At 12 months following angioplasty 43% of limbs still showed an improvement in blood flow compared with the measurement made before angioplasty. However, a number of these limbs showed a significant fall in limb blood flow between 3 weeks and 12 months even though the 3 week and the 12 month flow figures were still greater than those before angioplasty. The degree of initial improvement in blood flow seen at 3 weeks persisted at 12 months after angioplasty without significant fall in only 30% of limbs. In 33% of limbs where the balloon angioplasty was technically successful there was no improvement in blood flow at 3 weeks. 80% of these limbs had further significant untreated disease angiographically, compared with 43% of limbs where there was an increase in limb blood flow.

Cardiopulmonary Support (CPS) was employed electively in 13 patients during high risk percutaneous transluminal coronary angioplasty (PTCA) in accordance with a selection criteria, which included at least two of the following; (i) left ventricular ejection fraction of less than 35%, (ii) target vessel(s) supplying more than 50% of the viable myocardium, and (iii) patients refused coronary bypass surgery. The mean age of the patients was 56.8 +/- 10.7 years (range 39-77). PTCA was attempted in a total of 35 lesions in 12 patients; 29 lesions were successfully dilated (technical success rate of 82.9%). On average, 2.7 lesions were attempted in each patient, and 2.2 lesions were successfully dilated per patient. In one patient the procedure was abandoned due to dissection of the iliac artery during cannulation. One patient died of a large pulmonary embolism 72 h after the procedure. All the surviving 11 patients who had successful PTCA on CPS showed symptomatic improvement during a mean follow-up period of 18.5 +/- 4.3 months (range 11 to 24 months). The commonest complication encountered following the CPS-assisted PTCA was local haematoma (nine of 13 patients), but all patients required transfusion due to significant periprocedural blood loss. Our early experience suggests that CPS enhances the safety of undertaking PTCA in high risk patients.