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Biomedical subjects

D E Malone

Publications and source records attributed to D E Malone.

At least 37 records · Page 2Linked to original sources
PubMed1994

Hepatic interstitial laser photocoagulation: demonstration and possible clinical importance of intravascular gas.

PURPOSE: To investigate gas formation during hepatic interstitial laser photocoagulation (ILP). MATERIALS AND METHODS: In vitro, ILP was performed with a neodymium yttrium aluminum garnet laser on a piece of liver in a water bath. In vivo, nine pigs underwent 24 ultrasound (US)-monitored ILP procedures. Fiber tips were more than 1 cm from (n = 16) or adjacent to (n = 8) intrahepatic veins. The gas production seen on US images was graded on a scale of 0 to 4. Precordial Doppler US was performed in all cases. RESULTS: In vitro, smoke bubbles emanated from the vessels during ILP. In vivo, US showed intravascular gas production during nine of 15 exposures of at least 500 seconds duration. Gas production scores of 2 or more were recorded for nine exposures. Intracardiac gas was identified on eight precordial Doppler US recordings. All animals survived. CONCLUSION: Gas was detected in the heart during some ILP exposures. Patients with a probe-patent foramen ovale (24% prevalence) could be at risk for paradoxic air embolus during ILP.

Animals↗
PubMed1994

High-resolution ultrasound in assessment of the gastrointestinal tract.

Ultrasound (US) is frequently the first investigation performed in patients presenting with a variety of abdominal symptoms, and there is a growing appreciation of its value in a wide range of gastrointestinal (GI) disorders. The advantages of US are that it is quick, safe, readily available, noninvasive, and avoids ionizing radiation. It is now the primary imaging investigation when conditions such as appendicitis and hypertrophic pyloric stenosis (HPS) are suspected. For the diligent examiner careful assessment of the bowel can be rewarding either by diagnosing bowel pathology or identifying possible pathology and determining the most appropriate sequence of diagnostic investigations. Its real time capabilities are of particular usefulness in abdominal conditions; clinical correlation is instant and features such as peristalsis and bowel compressibility can be readily assessed. This review describes and illustrates the current role of high-resolution transabdominal US in the detection of GI pathology with discussion on some of the applications of endoscopic ultrasound (EUS) as they relate to this topic.

Digestive System Diseases↗
PubMed1994

Focal nodular hyperplasia of the liver--an imaging conundrum.

Focal nodular hyperplasia is a common benign tumour of the liver that usually does not require treatment. This tumour can be difficult to distinguish noninvasively from other lesions in young patients that may require intervention, such as hepatic adenoma and fibrolamellar carcinoma. The authors report three cases of histologically proven focal nodular hyperplasia and one case in which the imaging features strongly suggested this tumour. These cases illustrate many of the variable imaging features of focal nodular hyperplasia. The authors review the typical imaging findings for focal nodular hyperplasia, hepatic adenoma and fibrolamellar carcinoma, indicate the areas of overlap that make noninvasive diagnosis impossible and discuss the role of percutaneous biopsy in establishing the definitive diagnosis.

Adult↗
PubMed1994

Perforated jejunal diverticulosis: radiologic diagnosis.

Jejunoileal diverticulosis, which is usually asymptomatic, is commonly found at autopsy or during small-bowel barium examination. Perforation of diverticula can cause generalized or localized intra-abdominal inflammatory disease, depending to some extent on the site of the perforation. The authors describe a patient with perforation of a jejunal diverticulum; the condition mimicked colonic inflammatory disease clinically and ultrasonographically. The correct diagnosis was made on the basis of the findings of cross-sectional imaging and barium examination.

Diverticulum↗
PubMed1993

Same-day computed tomography during arterial portography and delayed high-dose iodine computed tomography: an efficient approach to imaging potentially resectable liver tumours.

Preoperative imaging in patients with potentially resectable liver tumours has traditionally been performed in specialized hepatobiliary centres. To assess the feasibility and value of establishing a same-day, pre-resectional hepatic imaging service, computed tomography during arterial portography (CTAP) and delayed high-dose iodine computed tomography (DICT) were used to examine patients considered suitable for curative hepatic resection. The study group comprised 27 patients (14 from hospitals not affiliated with a university and 13 from two university-affiliated hospitals) for whom pre-referral imaging showed tumour distribution amenable to resection. Among the patients from centres not affiliated with a university, seven had undergone ultrasonography (US) and equilibrium-phase CT, four had undergone US and unenhanced CT, two had undergone equilibrium-phase CT only and one had undergone bolus dynamic incremented CT (BDCT) only. For 12 of the patients coming from the university-affiliated centres, the pre-referral imaging had consisted of US and BDCT; the other had undergone US only. After CTAP and DICT, 20 (74%) of the 27 patients were reclassified as having unresectable disease: 7 (54%) of the 13 patients who had undergone BDCT before CTAP and DICT and 12 (92%) of the 13 patients who had undergone unenhanced or equilibrium-phase CT, as well as the patient who had undergone US only. By averting laparotomy in 20 of the patients, CTAP and DICT resulted in short-term health care savings of about $160,000. These findings suggest that BDCT was underused in the hospitals not affiliated with university centres.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1993

Optimizing the detection of colorectal liver metastases within the Canadian health care system.

Colorectal metastases in the liver are common. In appropriately selected patients resection can increase the 5-year survival rate from 0% to 33%. When consulted by their surgery colleagues about patient selection, radiologists now have a wide choice of imaging methods, including nuclear medicine, ultrasonography, unenhanced computed tomography (CT), intravenously enhanced CT (by infusion or by the dynamic and delayed methods), arterially enhanced CT (specifically, CT arterial portography and CT angiography) and magnetic resonance imaging. In Canada this wide range of techniques has appeared in an era of cost constraint. This article discusses the surgical background for imaging colorectal metastases in the liver and reviews the available imaging methods. The authors present an algorithmic approach that attempts to balance the need for accuracy with the logistic and financial constraints under which radiologists work in Canada. They suggest that this algorithm would allow optimal use of available resources in most Canadian hospitals.

Colorectal Neoplasms↗
PubMed1993

Computed tomography during arterial portography in malignant carcinoid syndrome: a report of two patients.

Computed tomography during arterial portography (CTAP) and delayed high-dose iodine computed tomography (CT) have improved the preoperative localization of hepatic metastases from colon cancer. Nearly all patients presenting with malignant carcinoid syndrome have liver metastases, and removal of tumour bulk is considered the most effective means of management. To determine suitability for hepatic resection, CTAP and delayed high-dose iodine CT were used to evaluate the distribution of hepatic disease in two patients with malignant carcinoid syndrome. In both patients CTAP showed lesions not seen during recent dynamic incremented CT; the location of the lesions precluded resection. CTAP also demonstrated metastases less than 1 cm in diameter in one patient. Facial flushing (both patients) and hypotension (one) occurred during infusion of the contrast agent into the superior mesenteric artery. Because CTAP can demonstrate small hepatic metastases (less than 1 cm in diameter), it is recommended for patients with malignant carcinoid syndrome who are being considered for hepatic resection. The infusion of contrast media through the superior mesenteric artery may induce a carcinoid crisis, and prophylaxis with a somatostatin analogue is suggested.

Contrast Media↗
PubMed1992

Technical report: percutaneous cholecystostomy in acute acalculous cholecystitis.

Acute acalculous cholecystitis is a significant cause of morbidity and mortality in patients with other serious illnesses (Howard, 1981) and the mortality rate after surgical cholecystostomy may reach 15% (McGahan and Lindfors, 1989). Radiologically controlled percutaneous cholecystostomy is a safe, minimally invasive, procedure which may be curative (McGahan and Lindfors, 1989; Berger et al., 1989). Both cases described here were successfully treated by percutaneous cholecystostomy. A modified Seldinger technique was used in one and a direct 'trocar' puncture in the other. Percutaneous cholecystostomy, which is technically relatively straightforward, is now the treatment of choice for acute acalculous cholecystitis.

Acute Disease↗
PubMed1992

Post-laparoscopic cholecystectomy bilomas--preliminary experience.

The incidence of biloma formation after laparoscopic cholecystectomy (LC) is, in the early experience of many centres, significantly higher than after open cholecystectomy. We describe four cases representative of the possible spectrum of post-LC bile leaks and review the literature regarding the radiologic investigation and management of this complication. We suggest that post-LC bilomas should initially be drained percutaneously. Endoscopic cholangiography (ERC) should then be used to identify the source of the leak, but sphincterotomy and/or stent placement may be best reserved for those whose leaks do not resolve after 10 days of free drainage. Surgery is recommended only for major biliary injury and for leaks that remain unresolved after sphincterotomy and/or stenting. An algorithmic summary of this approach is presented.

Adult↗
PubMed1992

Sonographic changes during hepatic interstitial laser photocoagulation. An investigation of three optical fiber tips.

RATIONALE AND OBJECTIVES: Interstitial laser photocoagulation (ILP) destroys tumors thermally, using laser energy delivered from implanted optical fibers. The objectives of the study are to identify a fiber tip/delivered energy combination which produces lesions of useful size, visible on ultrasound (US) during ILP, and to compare ILP lesions and their US images. METHODS: Hepatic ILP was performed at laparotomy in six pigs, using three different fiber tips (cylindrical diffusing, spherical diffusing, plane-cut). US images were obtained during ILP, immediately after ("early" images), and before the animals were killed (2-2.5 hours, "late" images). Actual lesions were assessed histopathologically. RESULTS: Few US changes were seen around cylindrical diffusing and spherical diffusing tips until tip destruction. Plane-cut tips, at 1.5 to 2.0 W, produced prominent US images of the 1- to 2-cm thermal lesions. Early images tended to overestimate necrosis. Late images approximated necrosis. CONCLUSION: For US-controlled ILP, plane-cut tips are better than currently available cylindrical diffusing or spherical diffusing tips. Lesion image growth periods might enable control of lesion size. Further studies are needed to determine the consistency of the described relationship between lesion images and actual lesions.

Animals↗
PubMed1992

The gastrocolic trunk and its tributaries: CT evaluation.

Dilatation or occlusion of the gastrocolic trunk (GT) may be a clue to a portal venous or pancreatic pathologic condition. To evaluate the normal and abnormal appearances of the GT and its tributaries at computed tomography (CT), the CT scans, angiograms, and surgical-pathologic records of 21 patients with cancer of the pancreas and 15 patients with chronic pancreatitis were reviewed retrospectively. The CT examinations of 30 patients with metastatic disease of the liver and no known pancreatic disease were studied for comparison. A normal GT (2.6-4.7-mm diameter) was identifiable in 48% of the control group in CT scans obtained with 10-mm-thick sections and in 90% of CT scans obtained with 5-mm-thick sections. The GT was dilated in five patients with isolated splenic vein occlusion and in five patients with occlusion or stenosis of the portal-superior mesenteric vein confluence (P-SMVC) above the level of the GT entry into the superior mesenteric vein. The GT was obliterated in eight patients and was associated with P-SMVC occlusion. Findings at surgery confirmed tumor extension into the root of the transverse mesocolon in three patients with cancer of the pancreas. Abnormal findings at CT, however, do not enable differentiation between benign and malignant pancreatic diseases.

Chronic Disease↗
PubMed1992

Optimizing gallbladder stone lithotripsy: an international survey.

Rates of stone clearance with extracorporeal shock wave cholecystolithotripsy (biliary lithotripsy [BL]) initially reported by European groups were encouraging. An American multicenter BL study (the Dornier National Biliary Lithotripsy Study [DNBLS]) did not reproduce these results. The BL treatment strategies and 6-month stone clearance rates of six leading European and Japanese centers were compared with those of DNBLS. All foreign centers used adjuvant oral chemolitholysis and greater shock wave energies from the same lithotriptor as that in DNBLS. Six months after BL, the stone clearance rates at all six centers were higher than those of DNBLS. There were no significant differences in complication rates between centers. These findings suggest that the poor results of DNBLS were chiefly due to the use of low kilovoltage and few BL sessions. Increased energy levels and a fragment size end point of less than 5 mm optimize BL. Despite the popularity of laparoscopic cholecystectomy, BL can be recognized as a successful treatment alternative for patients with a low burden of radiolucent stones.

Cholelithiasis↗
PubMed1991

Technical report: Management of tract disruption due to radiologic T-tube extraction of a retained common bile duct stone.

When a T-tube is in situ after cholecystectomy and common bile duct exploration, the treatment of choice for retained common duct stones is removal through the T-tube tract. Tract disruption during stone removal is uncommon. It may be a significant complication resulting in biliary peritonitis. We report a case of tract disruption during removal of a stone through a T-tube tract and discuss its management.

Catheterization↗
PubMed1990

Technical problem: impacted retained distal common duct stone.

We report a three-stage technique for use when impacted, retained distal common bile duct stones are encountered. It minimises instrumentation of the ampullary region during any one interventional session, provides drainage of biliary and pancreatic ducts between sessions and, in our opinion, maximises the chances of safely extracting such a stone.

Aged↗
PubMed1990

The intercostal pathway for biliary lithotripsy: an evaluation.

Intercostal biliary extracorporeal shock wave lithotripsy (BESWL), an alternative method for targeting retrocostal gallbladders, was evaluated in a three-stage study. First, 10 pigs (three with implanted gallstones) underwent BESWL at different, increasing shock wave pressures. Histologic studies were done in seven animals and showed no macroscopic abnormalities. Microscopically, two pigs had 1-3-mm blood collections in the shock wave path. Next, 11 patients in whom subcostal BESWL was not feasible underwent intercostal BESWL. One patient complained of contact-site tenderness after BESWL, which resolved spontaneously. Transient elevations of aspartate aminotransferase occurred in two asymptomatic patients. Finally, both pathways were evaluated in 22 consecutive patients. Intercostal BESWL was the method of choice in only two patients. In each stage of the study all intercostally targeted gallstones fragmented. It is concluded that the intercostal pathway is a valid alternative whenever subcostal BESWL proves unsatisfactory.

Animals↗