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Biomedical subjects

R N Gibson

Publications and source records attributed to R N Gibson.

At least 55 records · Page 3Linked to original sources
PubMed1988

Ultrasound, CT, and MRI comparison in primary and secondary tumors of the liver.

Thirty-five patients with surgically removed or percutaneous biopsy-proven tumors were examined by ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). This retrospective study describes the appearance of the primary tumors and metastases and compares the sensitivity and specificity of the 3 imaging methods. Ultrasound, CT, and MRI examinations as well as clinical, operative, and/or histologic data were available for all 35 patients. Paramagnetic contrast agent gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) was used in 23 patients and a short TI inversion recovery MRI sequence was used in 23 patients, in addition to various spin echo MRI sequences. Thirteen patients were examined using both Gd-DTPA and the short TI inversion recovery sequence. Our comparative study--based on the following criteria: detection, size, location of the tumor, and portal vein involvement and bile duct dilatation--demonstrated an advantage of MRI over ultrasound in 16 of 35 cases, equal results in 17 of 35 cases and a disadvantage of MRI compared to ultrasound in 2 of 35 cases. With the identical criteria, MRI proved to be more informative than CT in 10 of 35 cases, equal in 21 of 35 cases, and less informative in 4 of 35 cases.

Adolescent↗
PubMed1988

Tocolytic and cardiovascular effects of the calcium antagonist diltiazem in the near-term pregnant rabbit.

Parturition was induced with a 1 U intravenous bolus dose of oxytocin in two groups of near-term pregnant rabbits chronically prepared with distal aortic catheters. One group (n = 7) received an intravenous infusion of diltiazem (270 micrograms/kg/min) and the other (n = 7) received saline solution. Parturition was markedly inhibited in the diltiazem-treated group, based on the time to delivery of the first and subsequent fetuses and the number of fetuses undelivered at the end of each study. A significant decline in maternal blood pressure was observed in the diltiazem-treated group, but no significant change in maternal heart rate occurred. These findings suggest that diltiazem may provide significant tocolysis without the reflex tachycardia that has been observed with other calcium antagonists. Further evaluation of the maternal and fetal cardiovascular effects of diltiazem as well as the establishment of lower effective tocolytic doses are warranted.

Animals↗
PubMed1988

Percutaneous transhepatic endoprostheses for hilar cholangiocarcinoma.

In patients with unresectable hilar cholangiocarcinoma, percutaneous transhepatic endoprosthesis insertion is one of the available methods of palliation. We reviewed our experience with it in 35 consecutive patients with hilar cholangiocarcinoma who were judged on clinical or radiologic evidence to be unsuitable for resective or palliative surgery. The 30-day mortality rate was 14 percent (5 of 35 patients). Of the remaining 30 patients, endoprosthesis placement was successful in 28, with 2 patients discharged with a permanent external drainage catheter. Twenty-four patients survived a median of 3 months (range 1 to 17 months), and 2 were lost to follow-up. Good or fair palliation of symptoms was achieved in 50 percent of the discharged patients and in 66 percent of those living longer than 3 months. We believe that percutaneous transhepatic endoprostheses can provide useful palliation in patients with hilar cholangiocarcinoma, even in the presence of advanced disease.

Adenoma, Bile Duct↗
PubMed1988

Spiral-shaped biliary endoprosthesis: initial study.

A new flexible, spiral-shaped biliary endoprosthesis is described. This spiral endoprosthesis can negotiate acute angles, can be cut to any length, and has been specifically designed to deal with the problem of stent migration. The authors report their initial experience with this endoprosthesis in 14 patients.

Adult↗
PubMed1988

The ultrasonographic appearances of hilar cholangiocarcinoma (Klatskin tumours).

The findings on ultrasound of 40 patients presenting between 1984 and 1987 who were subsequently proven pathologically to have hilar cholangiocarcinoma were reviewed. The sonograms of 17 other patients in whom pathological confirmation was not obtained but who were also presumed to have Klatskin tumours on clinical and radiological grounds, were also reviewed. All patients demonstrated intrahepatic bile duct dilatation with no evidence of free communication between the right and left hepatic ducts. A hilar mass was observed in 74% of the patients. Seventy-nine per cent of the hilar masses were of increased echogenicity relative to surrounding liver, 19% were of reduced echogenicity and 2% of mixed echogenicity. An intraluminal mass was seen in 21% of the patients and bile duct wall thickening was observed in 4%. The mass detection rate of different ultrasound equipment was also compared. In 15 patients the ability of ultrasound to predict the order of intrahepatic bile duct involvement was compared with cholangiography.

Adenoma, Bile Duct↗
PubMed1988

Interventional radiology in the biliary tract.

Interventional radiology in the biliary tract comprises an increasing range of techniques, most of which involve the percutaneous placement and manipulation of some type of catheter system in the bile ducts or gallbladder under imaging control. These techniques have become well established in the management of a number of benign and malignant biliary disorders.

Biliary Tract Diseases↗
PubMed1987

Doppler ultrasound in the diagnosis of intestinal ischemia.

Conventional ultrasound is unreliable in detecting narrowing of the visceral arteries. Two cases are reported in which duplex Doppler ultrasound correctly identified severe narrowing of the celiac artery. Doppler ultrasound promises to be more accurate than conventional ultrasound in the diagnosis of visceral ischemia and may help to identify those patients who may require angiography.

Aged↗
PubMed1987

Duplex ultrasound in the evaluation of portacaval shunts.

The results of ultrasound imaging combined with Doppler studies of blood flow are presented in two patients with surgical portacaval shunts performed for portal hypertension. Duplex scanning proved a quick and noninvasive method of confirming the patency of the anastomoses. The demonstration of appropriate Doppler flow signals across the shunt is the most convincing ultrasound evidence of patency. Portacaval shunts are more amenable to study by ultrasound than more peripheral shunts because the liver can be used as an acoustic window.

Adult↗
PubMed1987

Benign biliary strictures: a proposed combined surgical and radiological management.

A combined surgical and radiological approach to the management of complex biliary strictures is described. Radiological access for stricture dilatation or stone extraction is created at the time of surgery either by insertion of a transhepatic U-tube or superficial fixation of the afferent limb of the Roux-en-Y loop. Each of seven patients treated in this way had multiple complicating factors known to adversely affect the outcome of operative repair. Five of the seven have had an excellent outcome at a median follow-up of 15 months (mean 21 months, range 2-39 months).

Adult↗
PubMed1987

Measurement of bladder volume by real-time ultrasound.

The accuracy of a non-invasive method of measuring the volume of urine in the bladder using ultrasound was assessed 32 times in 18 patients with benign prostatic hypertrophy. A method originally used with B-mode scanners was applied to images obtained with a real-time scanner. Although the mean error of 8% of true volume (range -29% to +52%, standard deviation 23%) compared favourably with that of some series, the results were less accurate than those originally reported for this method using a B-mode scanner. Real-time ultrasound can provide an approximate measurement of bladder urine volume but is not sufficiently accurate in situations where more precise measurements of changes in residual urine are required.

Aged↗
PubMed1987

Comparison of ultrasonography, computed tomography and 99mTc liver scan in diagnosis of Budd-Chiari syndrome.

Ultrasonography, computed tomography and 99mTc liver scanning are all useful in diagnosis of patients with the Budd-Chiari syndrome. In a study to determine their comparative value characteristic findings were recorded in all nine patients at ultrasonography and in seven patients at computed tomography. In contrast 99mTc liver scan showed a characteristic pattern in only one of eight patients. In our experience intrahepatic venous abnormalities were seen better at ultrasonography than at computed tomography. In addition, abnormality in the direction of blood flow could be detected by pulsed Doppler examination. Ultrasonography is relatively inexpensive, readily accessible, does not require administration of radiation or contrast agents and therefore should be the primary non-invasive investigation of patients with Budd-Chiari syndrome, or those at risk of developing it.

Adult↗
PubMed1987

Real-time ultrasound measurement of bladder volume: a comparative study of three methods.

The accuracy of different ultrasound methods for determining the volume of urine in the bladder was compared using three methods in current use. Each method was applied to the same ultrasound images from 16 patients with prostatic hypertrophy. The calculated volumes were compared with the true volumes derived by measurement of voided and catheter-drained urine. All methods showed similar degrees of accuracy in quantifying bladder volumes. The range of errors of the best method tested was +/- 35% of true volume and this suggests that ultrasound measurement of bladder volume is not sufficiently accurate for many clinical and research applications.

Aged↗
PubMed1986

Liver atrophy complicating benign bile duct strictures. Surgical and interventional radiologic approaches.

The hepatic atrophy and hypertrophy complex has been described in a selected group of nine patients with benign bile duct stricture. The clinical features common to this group were a high biliary stricture and a long-standing history of cholangitis and intermittent jaundice. A history of multiple surgical procedures and associated vascular damage or portal hypertension is strongly suggestive of the atrophy and hypertrophy complex. The radiologic criteria for the diagnosis of this condition are presented. Computerized tomography and HIDA scintigraphy were valuable as noninvasive means to diagnose lobar liver atrophy. The atrophy and hypertrophy complex described herein poses significant therapeutic problems and demands approaches other than those normally applicable for high biliary strictures. A combined surgical and radiologic approach with additional interventional radiologic procedures may be appropriate in patients in whom hilar anastomosis is difficult or impossible.

Adult↗