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Biomedical subjects

W R Lees

Publications and source records attributed to W R Lees.

At least 73 records · Page 4Linked to original sources
PubMed1993

The percutaneous rotary lithotrite: a new approach to the treatment of symptomatic cholecystolithiasis.

This report evaluates the use of a new device for destruction of gall stones, the Kensey-Nash Lithotrite (Baxter Corporation, California, USA). The principle of the instrument is that of a liquidiser with an impeller that emulsifies stones. Twenty five patients were treated; 13 patients were considered unfit for conventional treatment (complex group) and 12 elected to have the procedure (non-complex group). In the complex group nine patients were treated under local anaesthesia. Only six of the 13 patients had a clear gall bladder at the end of the first procedure, but after further treatments that included cholecystoscopy, endoscopic sphincterotomy, and percutaneous cholecystolithotomy 11 patients had a gall bladder free of stones. The morbidity was high, mainly due to pain and bile leaks, causing prolonged stays in hospital (median 18 days). In the non-complex group six patients had the procedure performed under local anaesthesia. Ten patients had a successful clearance of the gall bladder, and the remaining two patients had the stones removed at cholecystoscopy. Despite good clearance, the morbidity was high, with eight emergency admissions on account of complications and a prolonged duration of stay (median 13 days). In conclusion the technique is effective, but the morbidity is high. Further development is required if this technique is to be included in the alternative treatments for the management of gall stones.

Adult↗
PubMed1993

Hepatic metastases: interstitial laser photocoagulation with real-time US monitoring and dynamic CT evaluation of treatment.

Fifty-five liver metastases in 21 patients were treated with interstitial laser photocoagulation (ILP). Tumors were irradiated with a neodymium yttrium aluminum garnet laser via optical fibers passed through 19-gauge needles inserted under ultrasound (US) guidance. Heating of the tumor was evident at real-time US as an expanding and coalescing echogenic zone around the needle tips. After ILP, dynamic computed tomography (CT) showed laser-induced necrosis as a new area of nonenhancement. Necrosis of tumor volume was more than 50% in 82% (45 of 55) of the tumors, and 100% necrosis was achieved in 38% (21 of 55). Metastases smaller than 4 cm in diameter were treated more effectively and required fewer treatment sessions than did those larger than 4 cm. Complications were minor and included severe pain in four cases, persistent pain for up to 10 days in 11 cases, and asymptomatic subcapsular hematoma (four cases) and pleural effusion (six cases) seen with CT. ILP is safe and effective for liver tumor destruction, and US and CT are useful in different aspects of treatment monitoring.

Adult↗
PubMed1993

Prostate cancer and the role of color Doppler US.

PURPOSE: To determine the role of color Doppler imaging (CDI) in diagnosis of prostate cancer. MATERIALS AND METHODS: Transrectal ultrasound (TRUS) and CDI were performed in 456 patients with possible prostate cancer. Of these patients, 158 underwent prostate biopsy, and these formed the study group. RESULTS: The frequency of malignancy was 47% (75 of 158). Of 136 TRUS-positive cases, 72 were malignant and 64 benign. Of 84 CDI-positive cases, 65 were malignant and 19 benign (chi 2 = 12.18, P < .001). Thirteen percent of histopathologically proved cases (10 of 75) were normal at CDI. TRUS alone had a sensitivity of 96% and a positive predictive value (PPV) of 0.53. The addition of CDI increased the PPV to 0.77 but reduced the sensitivity to 87%. In only one case out of 158 did CDI suggest the diagnosis of malignancy independently of TRUS. CONCLUSION: CDI improves the PPV of TRUS but appears to have little additional value over TRUS alone in diagnosis of prostate cancer.

Aged↗
PubMed1993

MR cholangiography: clinical evaluation in 40 cases.

PURPOSE: To determine the reliability and efficacy of magnetic resonance (MR) cholangiography in demonstrating the site and extent of stricture. MATERIALS AND METHODS: In 40 patients with obstructive jaundice, three-dimensional MR cholangiography was performed with a sequence of mirrored fast imaging with steady-state precession and was compared with conventional cholangiography in 39 cases. The level of obstruction was determined by examining all imaging data available. RESULTS: Diagnostic MR cholangiograms were acquired in 39 patients; absence of obstruction was confirmed in three, and obstruction was seen in 36. The level of obstruction or absence of obstruction was accurately shown in 36 of 40 patients with MR cholangiography and in 37 of 39 patients with conventional cholangiography. The peripheral biliary tree was shown more completely with MR cholangiography than with endoscopic retrograde cholangiography in all 32 patients undergoing diagnostic studies with both modalities. CONCLUSION: Three-dimensional MR cholangiography shows particular promise for the assessment of complex strictures, in which conventional cholangiography carries a higher risk of sepsis, for planning optimal drainage before intervention.

Adult↗
PubMed1993

Colour Doppler and duplex ultrasound assessment of Peyronie's disease in impotent men.

280 patients (aged 28 to 74 years, mean 57) with erectile failure (EF) underwent colour Doppler and duplex ultrasound imaging (CDI) following intracorporeal papaverine. After achieving a full, or nearly full, erection visual inspection and palpation revealed plaques and/or constriction or deformity of the penis in 55 (20%) cases. 10 (4%) were known to have Peyronie's plaques prior to referral. Of these 55 patients ultrasound showed focal echogenic plaques in 14 (25%) and diffuse thickening of the tunica albuginea in 41 (75%). CDI diagnosed arteriogenic EF in 20 (36%) of these patients, venous leak in 10 (18%), arterial and venous in two (4%) and a normal response in 23 (42%). In 11 (20%) patients (seven with arteriogenic EF and four with venous leak) the plaque was seen to be affecting vessels. These results indicate that abnormalities of the tunica albuginea are far more common in patients presenting with erectile failure than previously thought. We believe that the diffuse thickening is a form of Peyronie's which is only recognized after pharmacological induction of penile erection.

Adult↗
PubMed1993

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.

Adult↗
PubMed1993

Ultrasound contrast hysterosalpingography--evaluation as an outpatient procedure.

Ultrasound contrast hysterosalpingography (HSG) uses intrauterine contrast media to increase the diagnostic value of plain transvaginal ultrasound enabling the uterine cavity contour to be assessed and allowing tubal patency to be determined. We present our experience using both negative (sterile saline) and positive (Echovist, Schering) contrast media in 27 patients presenting with a wide range of gynaecological disorders. This is the first report comparing the use of the two contrast media with plain ultrasound on a purely outpatient basis. We have found ultrasound saline HSG to be superior for the delineation of the uterine cavity and we predict that this will become a first line investigation for assessing the configuration of the uterine cavity. However, although Echovist could be demonstrated flowing through patent fallopian tubes, we found ultrasound contrast HSG to be insufficiently accurate in the determination of tubal patency and do not feel that it can replace conventional X-ray HSG. We review the literature on this technique and discuss its future role in gynaecological imaging.

Adult↗
PubMed1993

Technical note: interstitial laser photocoagulation for the treatment of prostatic cancer.

Interstitial laser photocoagulation (ILP) is a new percutaneous technique for local ablation of deep-seated tumours. We have applied this to treat a focal abnormality in a patient with prostatic carcinoma, under local anaesthesia and sedation. Transrectal ultrasound and computed tomography (CT) were used to guide three 18G needles, inserted transperineally, into the abnormal area. A thin (0.8 mm outer diameter) optical fibre was passed down each needle, so that the tip of the fibre lay within the tumour. The other end of the fibre was connected to a portable diode laser, which was activated at 2 W for 500 s. Real-time monitoring with ultrasound showed a gradually enlarging echogenic zone around the fibre-tip and a marked increase in colour Doppler signal; the echogenicity and Doppler signal decreased within a few minutes of completing treatment. Dynamic CT treatment 10 days later showed the treated area as a non-enhancing, avascular zone. Biopsies from this region confirmed the presence of necrosis. There were no complications. ILP appears to be a safe and effective way of ablating areas of focal abnormality in the prostate.

Aged↗
PubMed1993

Interstitial tumour photocoagulation.

Interstitial laser photocoagulation (ILP) is a new technique of in situ tumour destruction, using low power laser light energy, delivered percutaneously via thin optical fibres. We have applied this to treat patients with tumours of the liver, breast, and prostate, using sedation and local anaesthesia, and an Nd:YAG (1064 nm) laser or a new portable diode (805 nm) laser. Tumour necrosis has been optimized by using a 1 x 4 fibre coupler which splits the laser beam, and allows equal delivery of energy down 4 fibres simultaneously; the most promising results to date are with treating liver metastases with smaller tumours (< 3 cm) often being completely destroyed. With further improvements in laser parameters and fibre-tips, and in the evaluation of the thermal effects of ILP by imaging, it may be possible to apply this technique to completely destroy small deep-seated tumours in other organs. With optimal technique, ILP may in the future become a practical, minimally invasive treatment option for patients with tumours of the liver and breast, in conjunction with systemic therapy.

Adenocarcinoma↗
PubMed1992

Multiple-fibre low-power interstitial laser hyperthermia: studies in the normal liver.

Multiple four-fibre low-power interstitial laser hyperthermia was performed in the canine liver to establish the parameters with which large areas of thermal necrosis could be made. Using 1.5 W for 670 s (4020 J in total) and a fibre spacing of 1.5 cm, lesions with dimensions of 3.6 x 3.1 x 2.8 cm were achieved in 75 per cent of those attempted. There was no mortality and a low morbidity rate. These lesions could be visualized in both their development and resolution using ultrasonography. Healing occurred by 1 year. Temperatures in the centre of the heated region were 60 degrees C, which is more than enough to cause thermal cell death. There was good correlation between the temperatures recorded, the sonographic changes seen, and the pathological evidence of necrosis. Multiple-fibre low-power interstitial laser hyperthermia performed with ultrasonic guidance may be of use in the treatment of liver tumours.

Animals↗
PubMed1992

Ultrasound features of low power interstitial laser hyperthermia.

Low power interstitial laser hyperthermia (ILH) is a reliable means of producing in situ thermal necrosis. Ultrasonic studies have been carried out of the changes that occur in canine liver during ILH performed at laparotomy. With a single fibre delivering Nd-YAG laser at 1-1.5 W for 670 s an hyperechoic region developed at the fibre tip measuring 5-6 mm in diameter; around this developed an area of hypoechoic change (up to 500s) giving a total area of changed echogenicity of 14-16 mm. With a multiple fibre system using 4 laser fibres simultaneously the sonographic changes were a summation of the changes seen with a single fibre, the hypoechoic areas overlapping. With this four fibre system the creation of large (3.5 x 2.8 cm) areas of thermal necrosis was possible. There was good correlation between the sonographic and pathological measurements of the region of thermal change. The sonographic studies showed the extension and overlap of regions of thermal necrosis and allowed visualization and accurate measurement of the area undergoing change. The same combined technique has been successfully applied in a small number of clinical cases and may be of use in the treatment of tumours in solid organs.

Animals↗
PubMed1992

The characterization of pancreatic and bile duct tumours by duplex Doppler.

Duplex Doppler imaging was used to study the effect of pancreatic and bile duct tumours on portal vein and hepatic artery blood flow and the specific Doppler signals recorded from these tumours. Chaotic portal vein flow occurred in 35% (14) of pancreatic and 20% (6) of biliary tumours and complete portal vein occlusion in 28% (11) and 10% (3) respectively. Twenty-eight per cent (11) of pancreatic and 7% (2) of bile duct tumours had high frequency shift Doppler signals and 22% (9) of pancreatic tumours had a signal indicating low impedence flow. Both signal types are suggestive of malignancy. The results suggest that pulsed Doppler imaging has a valuable place in the ultrasound assessment of portal vein wall invasion, is an important staging criterion for pancreatic and biliary tumours and may assist in differentiating benign from malignant lesions.

Aged↗
PubMed1992

Interstitial laser hyperthermia: a new approach for treating liver metastases.

The palliative management of hepatic metastases remains unsatisfactory. There is a need for a simple non invasive technique which can stop or retard the rate of tumour growth. In principle, Interstitial Laser hyperthermia may fulfil such a role. In experimental studies, this technique produced precise in situ necrosis within solid organs which healed safely. In a pilot feasibility study, we treated ten patients with a total of 18 hepatic metastases on 31 occasions using a percutaneous approach to achieve an overall objective response rate of 44%. The treatment proved simple to perform, was well tolerated and produced radiological evidence of necrosis in small metastases (diameter less than or equal to 3 cm). However, further research is required before the technique can be regarded as established. Its future role in most cases will be to control the growth of discrete hepatic metastases unsuitable for resection. In instances where the extent of necrosis can be matched accurately to tumour volume, the potential for cure exists.

Aged↗
PubMed1992

Pre-operative assessment of Peyronie's disease using colour Doppler sonography.

Colour Doppler ultrasonography was used to assess 39 patients with Peyronie's disease with a suspected organic cause for their impotence. In 20 patients who complained of a uniform loss of erection, the impotence was likely to be functional in origin (90%) or occasionally venogenic (10%), the penile arterial blood flow being normal. However, patients who complained of distal flaccidity were likely to have an organic cause for their impotence (68%). This was due to proximal arterial disease (10%), plaque involvement of the distal vessels (37%), veno-occlusive dysfunction (5%) or to the soft glans syndrome (16%).

Adult↗
PubMed1992

Endoscopic ultrasound for localisation of islet cell tumours.

In a prospective study endoscopic ultrasound localisation of pancreatic endocrine tumours was attempted in 21 patients with clinically suspected islet cell tumours. Most patients were referred after the failure of conventional imaging methods. Endoscopic ultrasound correctly identified the site of 12 of 15 insulinomas, one glucagonoma, and a diffuse pancreatic abnormality in a patient with multiple endocrine adenopathy. There were two true negative examinations and one technical failure. The sensitivity of endoscopic ultrasound was much greater than that of computed tomography or conventional transabdominal ultrasonography.

Adenoma, Islet Cell↗