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Biomedical subjects

W R Lees

Publications and source records attributed to W R Lees.

At least 55 records · Page 3Linked to original sources
PubMed1995

Venous leak surgery: long-term follow-up of patients undergoing excision and ligation of the deep dorsal vein of the penis.

OBJECTIVE: To review the long-term results and satisfaction of patients after venous leak surgery for the management of impotence caused by a failure of passive venous occlusion. PATIENTS AND METHODS: Twenty-seven patients (mean age 56 years, range 26-63) with erectile failure due to venous leakage, diagnosed on colour Doppler imaging (CDI) and pharmacocavernosometry and cavernosography, underwent venous leak surgery. In all cases the deep dorsal vein of the penis was excised and ligated along with any other large accessory veins. Patients were reviewed in out-patients at 3 months and asked to complete a questionnaire 1 year after surgery. RESULTS: Three months after surgery, 19 of 27 patients (70%) had been able to resume sexual intercourse, 17 (63%) had spontaneous erections and two (7%) required papaverine/prostaglandin E1. One year after surgery, 14 of 22 patients were able to achieve erections sufficient for sexual intercourse, although four of these required self-injection with papaverine. There were no serious complications, and when asked whether or not they would undergo the operation again, 13 of 20 said they would. CONCLUSIONS: We conclude that venous leak surgery is a useful treatment modality in patients with pure venous leakage proven by pharmacocavernosometry and/or cavernosography, and in whom arteriogenic impotence has been excluded using CDI. These are often desperate patients who would rather accept the risk that this relatively minor procedure may fail in preference to undergoing implant surgery in the first instance or use a vacuum device. However, well-informed consent is essential.

Adult↗
PubMed1994

Interstitial laser photocoagulation as a treatment for breast cancer.

This preliminary report describes the use of interstitial laser photocoagulation to manage small breast cancers. Forty-four patients were treated with a diode laser of 805 nm under local anaesthesia in the interval between diagnosis and surgery. Ultrasonography was used in 42 patients and computed tomography (CT) in two to place the fibre in the tumour and monitor laser effects. Laser-induced necrosis within the resected tumour varied from 0 to 25 mm in diameter. The presence of charring in the tumour around the fibre tip after treatment was associated with significantly larger diameters of necrosis than when charring did not occur (median 13 versus 6 mm, P = 0.002). Precharring the fibre resulted in a more predictable diameter of necrosis (median 14 mm). Ultrasonography was inaccurate in assessing laser damage; dynamic CT and magnetic resonance imaging may be of more use. Interstitial laser photocoagulation is simple and safe, and can produce necrosis of a reasonably predictable extent.

Breast↗
PubMed1994

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.

Humans↗
PubMed1994

Percutaneous cholecystolithotomy: is gall stone recurrence inevitable?

Using radiological interventional techniques the gall bladder can be cleared of stones with a high success rate. As with any treatment option that leaves the gall bladder in situ there is an accompanying risk of stone recurrence, which is currently unknown for the radiological method. One hundred patients were studied prospectively to determine the recurrence rate of stones and clinical outcome after successful percutaneous cholecystolithotomy. Follow up included both clinical assessment and ultrasound examination at 3, 6, and 12 months and then annual intervals thereafter. The overall stone recurrence rate was 31% at a mean follow up of 26 months (range, 3-50 months). By actuarial life table analysis, the cumulative proportion of gall stone recurrence was 7, 19, 28, 35, and 44% at 6, 12, 24, 36, and 48 months respectively. Of the 31 patients with recurrent stones; 17 remain asymptomatic, seven have experienced biliary colic, two abdominal pain, three non-specific upper gastrointestinal symptoms, and two jaundice secondary to common duct stones. Thirteen of the stone free patients have remained symptomatic; six with abdominal pain and seven with nonspecific upper gastrointestinal symptoms. Eight patients have subsequently had a cholecystectomy. No significant difference was found between the sex of the patient or the number of stones before treatment and the stone recurrence rates. The cumulative stone recurrence rate was significantly less in the 56 patients who received adjuvant chemolitholysis (p < 0.05). These data show that stone recurrence after successful percutaneous cholecystolithotomy occurs in the minority, and is usually asymptomatic. It is concluded that the technique remains justified in the management of selected patients with gall stones.

Chenodeoxycholic Acid↗
PubMed1994

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.

Female↗
PubMed1994

Biopsy of inoperable pancreatic tumors does not adversely influence patient survival time.

PURPOSE: To determine the influence of pancreatic biopsy on the survival times of patients with inoperable tumors of the pancreas. MATERIALS AND METHODS: One hundred seventy patients were examined; results of histologic analysis confirmed pancreatic malignancy in 119. The biopsy and nonbiopsy groups were comparable for age, sex, the presence of liver metastases, and nodal status. RESULTS: No statistically significant difference was demonstrated between the survival time for the biopsy group (median, 23 weeks) and that for the nonbiopsy group (median, 22 weeks). The estimated relative risk for death (biopsy group compared with nonbiopsy group) was 0.85 (95% confidence limits = 0.61, 1.18). CONCLUSION: Pancreatic biopsy does not appear to adversely influence survival time for patients with inoperable pancreatic tumors. Because histologic examination aids clinical management, biopsy should be part of the diagnostic work-up for patients with suspected inoperable pancreatic carcinoma.

Aged↗
PubMed1994

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.

Aged↗
PubMed1993

Cholangiocarcinoma: ultrasound features and correlation of tumor position with survival.

Cholangiography is the definitive imaging modality for assessing cholangiocarcinoma. This study was designed to evaluate the ultrasound (US) features of cholangiocarcinomas and assess the accuracy of US in mapping tumor site when compared to cholangiography. Findings were correlated with patient survival. Thirty-one patients with an US diagnosis of cholangiocarcinoma underwent cholangiography. The US diagnosis was correct in 29 of 31 cases. Complete agreement with cholangiography occurred in 23 (78%) cases. In six patients, there was discrepancy over the precise tumor location. US diagnosis of cholangiocarcinoma had a high predictive value (0.94) and proved an accurate method of mapping tumor site. Lesions arising in the hilar region carried a worse prognosis (50% were dead within 80 days).

Adenoma, Bile Duct↗
PubMed1993

Colour flow and spectral Doppler imaging after papaverine-induced penile erection in 220 impotent men: study of temporal patterns and the importance of repeated sampling, velocity asymmetry and vascular anomalies.

Of 220 impotent men studied, 52 demonstrated venous leakage, 85 had arterial insufficiency and 65 showed normal vascular response. Persistent diastolic velocity > 7 cm/s diagnosed venous leakage with a sensitivity of 94% and a specificity of 69%, using cavernosography as the reference standard. Using clinical response as the reference standard maximal systolic velocity of 30 cm/s identified normal penile arterial response with a sensitivity of 96% and specificity of 82%. There was a good correlation between penile arterial insufficiency and a strong history of arteriopathy. Time to peak systole > 0.1 s was a reliable predictor of arteriogenic impotence and Pulsatility Index (PI) < 300 was discovered only in patients with either venous leakage or arteriogenic impotence. Peak systolic velocity (Tmax) occurred between 5.2 and 6.5 min after injection, and diastolic velocity was minimal at 9 min with only the normal responders showing reversed diastolic flow. However, 22% had a delayed response (Tmax range 1-18 min). Velocity asymmetry was equally common in the three groups and unilateral sampling would have misdiagnosed 6% of patients studied. Vascular anomalies were seen in 13%, particularly a single feeding artery, dorsal vein flow or collateral arterial flow.

Adult↗
PubMed1993

Local treatment of colorectal liver metastases: a comparison of interstitial laser photocoagulation (ILP) and percutaneous alcohol injection (PAI).

The purpose of this study was to evaluate the relative merits of two physical methods of locally destroying colorectal liver metastases-interstitial laser photocoagulation (ILP) which causes thermal necrosis, and percutaneous alcohol injection (PAI) which causes cellular dehydration and coagulative necrosis. Seventy-six liver metastases in 22 patients were treated by ILP or PAI. Both techniques were performed using local anaesthesia and intravenous sedation/analgesia. Ultrasound was used to localize the tumours and guide the needles percutaneously. ILP: Up to eight 19 G needles were inserted into the tumour, and down each needle was passed a thin optical fibre; the tumour was heated using low power laser light (2 W) for 500 s from a Nd:YAG or diode laser. PAI: 0.5-1 ml of sterile 95% absolute alcohol was injected into multiple sites of the tumour using a single 19-22 G needle. Dynamic CT scan was used to evaluate the extent of treatment-induced necrosis. Ultrasound showed echogenic changes around the needles/fibre-tips during ILP and PAI; this gave a reasonable guide to the extent of thermal damage for smaller tumours during ILP, but not during PAI. ILP: 54 tumours were treated (median size 2.7 cm). Laser-induced necrosis was clearly seen 24 h after treatment as a well-defined area of non-enhancement on the dynamic CT scan; greater than 50% necrosis of tumour volume was achieved in 87% of tumours (complete necrosis was found in 52% of tumours). PAI: 22 tumours were treated (median size 1.5 cm). Dynamic CT showed patchy areas of non-enhancement in five tumours, decreased density in seven tumours, and no change in 10 tumours; complete tumour necrosis was never achieved. There were no major complications after ILP or PAI, but pain during treatment was more common and more severe with PAI. ILP is a simple, safe and effective treatment for colorectal liver metastases; PAI is relatively ineffective for these tumours (although it has been shown to be much more effective for small hepatocellular carcinomas).

Adult↗
PubMed1993

Tumefactive biliary sludge: a sonographic pseudotumour appearance in the common bile duct.

Two patients with obstructive biliary symptoms were shown to have dilated bile ducts on ultrasound. Within the lumen of both distal common ducts (CBD) large low echogenicity polypoid masses without acoustic shadowing were seen. MRI in one patient showed a polypoid filling defect in the lower CBD corresponding to the ultrasound appearance. Instrumentation at the lower end of both CBDs caused disintegration of the polypoid configuration resulting in the more typical layered appearance of biliary sludge. Sludge in the gall-bladder as seen on ultrasound is rarely known to cause a pseudotumour appearance. It has not previously been reported as occurring in the CBD and awareness of the tumefactive appearance of biliary sludge in the common duct is important and should help avoid possible misinterpretation.

Adult↗
PubMed1993

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.

Angioplasty, Balloon↗
PubMed1993

Computed tomography-pathologic assessment of laser-induced necrosis in rat liver.

RATIONALE AND OBJECTIVES: Interstitial laser photocoagulation (ILP) causes localized tissue necrosis. This study was performed to determine 1) whether the changes seen on computed tomography (CT) correspond to the necrosis pathologically, and 2) which CT technique best shows the necrosis. METHODS: Eighteen Wistar rats had ILP to their liver using a neodymium yttrium aluminum garnet [Nd:YAG] laser. Radio-opaque markers attached to the liver defined an imaging plane. Precontrast "dynamic" and delayed CT scans were performed. The size of necrosis was measured on CT, and macroscopically after resecting the liver. Computed tomography density numbers were measured from the necrotic area and normal liver for each CT technique. RESULTS: There was a good correlation between the necrosis size on CT and pathologically (P < .001). Maximum lesion-to-liver contrast was obtained on "dynamic" CT scans. CONCLUSIONS: The extent of tissue density changes on CT in rat liver after ILP match the extent of necrosis seen pathologically. The best CT technique use assessed for evaluating laser-induced liver necrosis is dynamic contrast-enhanced scanning.

Animals↗