Three-dimensional fetal ultrasound.
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Female↗
Biomedical subjects
W R Lees
Publications and source records attributed to W R Lees.
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↗
Interventional radiology of the gallbladder.
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Biopsy, Needle↗
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↗
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↗
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↗
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↗
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↗
Selection, management, and early outcome of 113 patients with symptomatic gall stones treated by percutaneous cholecystolithotomy.
Between January 1988 and December 1990, 283 patients with symptomatic gall stones were referred for non-operative treatment. After ultrasound scanning including a functional assessment, 220 (78%) patients were found to be suitable for percutaneous cholecystolithotomy. Of these, 113 underwent the procedure including 10 in whom extracorporeal shock-wave lithotripsy or methyl tert-butyl ether therapy had failed. Forty four patients underwent extracorporeal shockwave lithotripsy, methyl tert-butyl ether therapy or rotary lithotripsy, 46 chose laparoscopic cholecystectomy or minicholecystectomy and 27 declined treatment. Percutaneous cholecystolithotomy was successfully performed in 100 patients. Thirty four patients were a high operative risk and 14 presented with an acute complication of gall stone disease. Complications developed in 15 patients, all of whom were managed conservatively and most occurred during development of the technique. Outcome has been assessed clinically and by ultrasound scanning in 92 patients with a median follow up period of 14 months (six to 37 months). Seventy nine per cent were completely cured of their symptoms. Ninety three per cent of gall bladders were shown to be functioning and nine (9.8%) contained stones, although five of these are believed to have developed from residual fragments. Percutaneous cholecystolithotomy is a safe, non-operative treatment for symptomatic gall stones and enabled the patient to fully recover within two to three weeks; it has a definite role in the management of the elderly and high risk patient but its use for the treatment of other groups is likely to remain controversial.
Adolescent↗
US-guided percutaneous pancreatography: an essential tool for imaging pancreatitis.
The pancreatic duct can be opacified when contrast material is injected through a fine needle percutaneously placed under ultrasound (US) guidance. Percutaneous pancreatography was performed in 63 patients with chronic pancreatitis diagnosed at US or computed tomography (CT). In 52 of these patients, endoscopic retrograde pancreatography (ERP) was unsuccessful or did not enable complete visualization of the duct. The percutaneous pancreatograms and other relevant images of these patients were retrospectively reviewed. Percutaneous pancreatography was successful in 54 patients (86%), in whom it clearly mapped the full ductal anatomy, depicted the relationship between cavities seen at US or CT and the duct, and allowed assessment of duct drainage after antegrade injection of contrast material. This information was not provided by other modalities. Percutaneous pancreatography is a valuable complement to CT, US, and ERP for imaging chronic pancreatitis.
Cholangiopancreatography, Endoscopic Retrograde↗
Percutaneous techniques for the management of symptomatic gallbladder stones.
Several non-operative treatments for the management of patients with symptomatic gallstones have been developed with the purpose of avoiding the considerable morbidity associated with open cholecystectomy. Minimally invasive techniques utilizing direct percutaneous puncture of the gallbladder are being increasingly used for the diagnosis and treatment of gallbladder disease and are the subject of this review. With the emergence of laparoscopic cholecystectomy the role of these techniques is less certain but they are likely to continue to be important in the management of high risk, elderly or medically unfit patients.
Acute Disease↗
Independent evaluation of impotence by colour Doppler imaging and cavernosometry.
Colour Doppler imaging and cavernosometry are the optimal means for objective assessment of pharmacologically induced penile erections. 21 impotent patients were assessed by both methods independent of the information derived from the other modality. The diagnosis obtained was found to be immediately consistent in only 10 cases, 7 of which had venous leakage. 6 of the remaining 11 patients had a diagnosis of mixed arterial and venous disease in one or the other modality, but only arterial or venous disease alone in the other. The remaining 5 patients had completely inconsistent diagnoses. However, knowledge of the clinical picture and awareness of the pitfalls in the diagnostic procedures allows most of the discrepancies to be explained. Colour Doppler imaging is subject to operator error but allows selection of patients for cavernosography.
Erectile Dysfunction↗
Can cholangiography be safely abandoned in laparoscopic cholecystectomy?
The introduction of laparoscopic cholecystectomy, improvements in ultrasound technology and the success of endoscopic sphincterotomy have raised new questions regarding the role of intraoperative cholangiography. Our aim was to analyse the ability of preoperative clinical and ultrasound assessments to detect common duct stones in 86 patients with symptomatic cholecystolithiasis who then underwent cholangiography after percutaneous cholecystolithotomy. Six patients gave a history suggestive of common duct stones (either jaundice, cholangitis or pancreatitis). Ultrasound showed a dilated common duct in four patients (normal < 6 mm), and one of these had a stone demonstrated in the duct. The latter patient and one other with a dilated common duct had stones on cholangiography (which were extracted at ERCP), no stones were demonstrated in the other two. Ultrasound correctly identified common duct stones in two and excluded common duct stones in four others with a history suggesting the presence of stones. For patients undergoing laparoscopic cholecystectomy we would advocate the use of preoperative ultrasound instead of intraoperative cholangiography, and that endoscopic retrograde cholangiopancreatography is performed in the small number of patients shown to have a dilated duct or common duct stone.
Cholangiography↗
Gallbladder sepsis after stent insertion for bile duct obstruction: management by percutaneous cholecystostomy.
Of 364 patients undergoing insertion of a biliary endoprosthesis in 1989, six (1.6 per cent) developed gallbladder sepsis. Three patients had cholangiocarcinoma, two had carcinoma of the pancreas and one had a benign biliary stricture. Two of the five patients with malignancy had gallbladder stones, and the patient with a benign stricture developed stones after 3 years of stenting. Three patients developed gallbladder sepsis early after endoprosthesis insertion (less than 6 days), while in the other three it occurred late (greater than 6 months). All six patients failed to respond to antibiotics and were successfully managed by percutaneous cholecystostomy; the patient with a benign biliary stricture also had cholecystolithotomy. The gallbladder drainage tubes were removed or became dislodged at intervals varying from 2 weeks to 6 months without complications. Percutaneous cholecystostomy is the treatment of choice for gallbladder sepsis unresponsive to antibiotics in patients with a biliary endoprosthesis in situ.
Adenoma, Bile Duct↗
Pre-operative localisation in primary hyperparathyroidism.
One hundred and seventy-three patients operated on for primary hyperparathyroidism over a four year period by one experienced surgeon are reviewed. An overall success rate of 98.8% was achieved with information from pre-operative localisation using ultrasound and parathyroid venography with sampling. Parathyroid ultrasound was heavily dependent on the experience of the operator. An experienced ultrasonologist detected 63% of solitary adenomas and correctly localised the site of 82%. Glands were not detected if they were of small size or in an inaccessible site. He identified all those enlarged glands over 0.36 grams in weight that were lying in the usual site. In contrast, inexperienced ultrasonologists had a detection rate of 20%. Parathyroid venography with sampling detected a single site of excess hormone production in the neck of 79% of patients with a single adenoma, and correctly localised the site in 75% of these. The side was correctly predicted for 63% of glands, the level was correctly predicted for 56% and both side and level localisations were correct in 44%. Multi-gland disease was correctly suggested by the experienced ultrasonologist in 56% of cases and by parathyroid venography with sampling in 31% cases.
Adenoma↗
A hypoechoic area within the head of the pancreas--a normal variant.
Using conventional pancreatic ultrasonography 32 healthy volunteers were studied to assess the prevalence of a previously undescribed well demarcated hypoechoic area within the head of the pancreas. There was definite evidence of a hypoechoic region in nine subjects (28.1%), possible evidence in five (15.6%) and no evidence in 18 (56.3%). In accordance with the structural differences that have been described between the embryologically derived ventral and dorsal pancreatic segments it is proposed that this area of hypoechogenicity is the ventral portion of the pancreas. To date any focal hypoechogenicity within the head of the pancreas has been considered abnormal, but in view of these findings we feel it is important to recognise that a well demarcated hypoechoic region within the head of the pancreas can be a normal variant.
Adult↗