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Biomedical subjects

A H Dachman

Publications and source records attributed to A H Dachman.

At least 37 records · Page 2Linked to original sources
PubMed1995

Islet cell tumors of the pancreas: pathologic-imaging correlation among size, necrosis and cysts, calcification, malignant behavior, and functional status.

OBJECTIVE: The purpose of our study was to correlate the imaging and pathologic features of islet cell tumors with regard to tumor size, necrosis and cysts, calcification, malignant behavior, and functional status. MATERIALS AND METHODS: We retrospectively reviewed the clinical, pathologic, and imaging features of all 133 cases of pathologically proved islet cell tumors of the pancreas seen at the Armed Forces Institute of Pathology. Clinical data, including the patients' symptoms and serologic characteristics, were used to distinguish hyperfunctioning tumors (those causing symptoms related to elevated serum polypeptide levels) from nonhyperfunctioning tumors; hyperfunctioning tumors were divided further into insulin-producing and non-insulin-producing types. All patients had at least one cross-sectional imaging study, including CT (n = 118), sonography (n = 42), or MR imaging (n = 22). Clinical, pathologic, and imaging features were evaluated and correlated with tumor size, necrosis and cysts, calcification, local invasion, vascular invasion, metastases, and functional status. RESULTS: Islet cell tumors with areas of necrosis or cystic change found pathologically and on imaging studies (56/133) were larger (8.4 cm in mean transverse diameter) than homogeneous solid lesions (2.9 cm in mean transverse diameter) and were predominantly non-insulin producing (48/56) and nonhyperfunctioning (36/56). Of the 43 insulinomas, 35 were small (2.2 cm in mean transverse diameter), solid, and homogeneous. Larger size also was associated with calcification and malignant behavior, including local invasion, vascular invasion, and distant metastases. CONCLUSION: Our findings show that cystic and necrotic islet cell tumors are usually non-insulin-producing and nonhyperfunctioning neoplasms and larger than the typically solid and small insulinomas. Calcification, local invasion, vascular invasion, and metastatic disease are more commonly seen with larger neoplasms.

Adenoma, Islet Cell↗
PubMed1994

Hodgkin's disease of the gastrointestinal tract.

Hodgkin's disease (HD) is rarely considered in the differential diagnosis of gastrointestinal (GI) disorders. We report eight cases of GI HD. The patients, ages 16-64, all with stage IV disease of varied histologic subtypes and GI symptoms including pain, upper or lower GI bleeding and/or obstruction. There was diffuse gastric fold thickening in one case, a large submucosal mass along the proximal greater curvature in another case, and a large ulcerating mass along the lesser curvature in the third case. Two cases of jejunal disease manifested as either a short or long segment of luminal narrowing with prominent mucosal nodularity. Another case exhibited a short area of complete mucosal destruction, irregular cavitation and intraluminal filling defect. In one additional case there was diffuse jejunal nodularity. Colonic involvement (two cases) presented as a solitary polypoid mass in transverse colon in one patient and severe narrowing of the descending colon with adjacent mesenteric mass on CT in another. We conclude that although rare in Hodgkin's disease, GI involvement should be considered, particularly in patients with stage IV disease.

Adolescent↗
PubMed1993

The radiologic evaluation of acute abdominal pain of intestinal origin. A clinical approach.

The patient with acute abdominal pain presents the attending physician with a wide and varied gamut of diagnostic possibilities. Prompt and accurate diagnosis is essential for the proper care and management of these acutely ill patients. Diagnostic radiology is often an integral part of the emergent evaluation of these patients. This article focuses on some of the key plain-film findings in the patients suffering from acute abdominal pain of intestinal causes and reviews the radiologic evaluation of several major abdominal conditions such as acute appendicitis, diverticulitis, inflammatory bowel disease, bowel ischemia, and infarction.

Abdominal Pain↗
PubMed1993

Prevalence and duration of postoperative pneumoperitoneum: sensitivity of CT vs left lateral decubitus radiography.

OBJECTIVE: The purpose of this study was to evaluate the prevalence, location, and duration of pneumoperitoneum in postoperative patients and to compare the sensitivities of CT and left lateral decubitus radiography in the detection of postoperative pneumoperitoneum. SUBJECTS AND METHODS: Twenty-seven CT scans and 27 abdominal radiographs with the patient in the left lateral decubitus position were obtained prospectively in 17 patients after uncomplicated abdominal surgery. Fifteen patients were examined 3 days after surgery and 12 were examined 6 days after surgery. The studies were evaluated in a blinded fashion for the presence, location, and volume of free air. The presence of air on the radiographs and the presence and quantity of air on the CT scans were correlated with each subject's surgical procedure, age, sex, and body habitus. RESULTS: Pneumoperitoneum was seen on 13 (87%) of 15 CT scans and eight (53%) of 15 radiographs obtained 3 days after surgery and on six (50%) of 12 CT scans and one (8%) of 12 radiographs obtained 6 days after surgery. The calculated volume of free air seen on the CT scans ranged from 0.3 to 5.8 ml. Sixty-two percent of collections by volume were located in the midline/parahepatic space, 22% in the pelvis, and 16% in the mesentery. Radiographs showed pneumoperitoneum in only nine (47%) of 19 examinations in which the corresponding CT scans showed free air. Findings on radiographs were false-negative in seven (87%) of eight obese patients in whom pneumoperitoneum was detected on CT scans. CONCLUSION: The prevalence of pneumoperitoneum in the postoperative period based on CT findings is greater than that previously reported. Small amounts of pneumoperitoneum frequently collect along the anterior abdominal wall in two preferential spaces, the pararectus and midrectus recesses. The results of this study show that CT is significantly more sensitive than plain radiography for detecting small amounts of free intraperitoneal air in postoperative patients. Radiography is particularly insensitive for imaging obese and heavy patients.

Adult↗
PubMed1991

Polypoid and pseudopolypoid manifestations of inflammatory bowel disease.

The polypoid manifestations of the idiopathic inflammatory bowel diseases (ulcerative colitis and Crohn disease) are often confusing. Inflammatory polyps project above the level of the surrounding mucosa. Pseudopolyposis (in ulcerative colitis) or a cobblestone appearance (in Crohn disease) results when extensive ulceration develops and only scattered islands of relatively normal mucosa remain; thus, the ulcerated areas may be falsely perceived as the baseline and the islands as polyps. Postinflammatory (filiform) polyps--fingerlike projections of submucosa covered by mucosa on all sides--reflect healing of undermined mucosal and submucosal remnants and ulcers and are almost always multiple. Patients with ulcerative colitis or Crohn disease are at increased risk for developing adenocarcinoma. Occasionally, dysplasia occurs as a polypoid lesion. Dysplasia of the colon (mucosal atypia) is a histologic marker highly associated with adenocarcinoma. Because differentiating adenocarcinoma and dysplasia from inflammatory or postinflammatory polyps is sometimes difficult or impossible, endoscopy and biopsy are usually recommended for definitive diagnosis of suspicious lesions.

Adolescent↗
PubMed1991

Radiology of the esophagus.

Plain films, esophagrams, and cross-sectional imaging studies have important roles in evaluating patients with suspected esophageal disease. The strengths and weaknesses of each technique are described in this article. The salient radiographic features of various inflammatory and neoplastic conditions of the esophagus are also described, with emphasis on the value of high-quality triphasic esophagography.

Carcinoma, Squamous Cell↗
PubMed1990

Animal model for fluoroscopically guided laser application in the biliary tree.

The purpose of this project was to develop an animal model for a fluoroscopically guided application of the contact neodymium-yttrium aluminum garnet (Nd-YAG) laser in the bile duct and identify the factors affecting the extent of damage to the duct wall. This model permits cholangiographic visualization of the duct during laser application. Laser damage is limited by using contact probes and firing the laser while slowly pulling the probe proximally into the duct. Sixteen common bile duct laser burns were produced in 14 dogs. Power settings of 8-25 W were used. The tension of the contact probe along the duct wall, termed "wall tension," was varied through intraoperative manipulation in order to mimic a variety of ductal geometries that might be encountered in clinical use. The authors produced duct damage ranging from a superficial burn to perforation. Power and wall tension were the most important factors in determining the depth and circumference of damage, and the use of 15 W or less did not perforate the duct.

Animals↗
PubMed1990

US-guided percutaneous laser ablation of liver tissue in a chronic pig model.

The authors evaluated the safety of ultrasound (US)-guided percutaneous ablation of liver tissue using a neodymium-yttrium-aluminum-garnet (Nd:YAG) laser fiber placed through a skinny needle. The US appearance of the lesion was correlated with the pathologic findings in 19 pigs killed at 1-7 weeks. A 20-gauge needle was percutaneously placed in the liver, and a fiber with a 0.5-cm cladding-stripped tip was inserted. The Nd:YAG laser was fired for 6 minutes at 1-4 W. The early sonographic appearance was recorded, and the US appearance before the pigs were killed was correlated with the gross and histopathologic findings. There were no cases of abdominal bleeding or infection. Mild transient changes in liver function were seen. An initial strong echogenic focus decreased slightly in echogenicity for 10 minutes and then stabilized. Over 1-7 weeks, the 1-cm-diameter lesion decreased in size and developed an echogenic rim that correlated with a peripheral zone of inflammatory repair around a small central cavity and zone of necrosis. US-guided laser ablation of liver tissue is safe in this pig model, and the US appearance corresponds to a process of repair and removal of necrotic liver tissue.

Animals↗
PubMed1989

Cronkhite-Canada syndrome: radiologic features.

We report 6 cases of Cronkhite-Canada syndrome, analyze the patterns of involvement, and review the literature on this entity. There were 4 women and 2 men, with an average age of 58 years. The stomach was diseased diffusely in 5 and focally (distally) in 1. Small bowel polyps were detected in 4 patients. Patterns of involvement were classified as (a) innumerable small polyps carpeting large areas, (b) scattered varying-size polyps, and (c) sparse involvement with few small polyps. There was concordance of patterns between the stomach and colon in 5 of the 6 patients.

Adult↗
PubMed1988

Colorectal hemangioma: radiologic findings.

The authors correlated radiographs with the clinical and histologic data of 12 patients with colorectal hemangioma. All patients presented with rectal bleeding, which was chronic in seven. Phleboliths were also visible in seven cases, which correlated with chronic bleeding in five. On barium studies, three masses were soft and three produced rigid narrowing. The atypical features of rigid luminal narrowing, which might mimic a carcinoma, and hypovascularity correlated with chronic bleeding or visible phleboliths, which suggest the correct diagnosis of colorectal hemangioma.

Barium Sulfate↗
PubMed1987

Tumors of the small intestine with little or no malignant predisposition: a review of the literature and report of 56 cases.

Benign small bowel tumors are rare. If those with malignant potential are excluded, a small group of truly benign lesions remains. Fifty-six cases of these small bowel tumors were analyzed for clinical data, pathologic diagnosis, number, size, location, and radiologic appearance. Lesions included lipoma, myoepithelial hamartoma, Peutz-Jeghers hamartoma, neurogenic tumors (including gangliocytic paraganglioma), Brunner's gland abnormalities, and inflammatory fibroid polyp. Location, number, and radiographic morphology can be helpful in reaching a more specific diagnosis. Age of patient and size of tumor may be helpful in the differential diagnosis; however, sex of the patient and clinical symptoms are not.

Adenoma↗
PubMed1987

Hemangioma of the spleen: radiologic-pathologic correlation in ten cases.

Ten cases of hemangioma of the spleen were reviewed. Plain abdominal radiographs and scintigrams are helpful in specifying the splenic location. Calcification, either central punctate or peripheral curvilinear, can be detected on radiographs or computed tomographic (CT) scans. The spectrum form solid to cystic change observed in the pathologic specimens is reflected in analogous patterns on CT scans and sonograms: predominantly solid mass; mass with cystic spaces. The angiographic findings are nonspecific. It is possible to suggest the diagnosis of hemangioma of the spleen when an asymptomatic patient presents with a discrete splenic mass, particularly if there is evidence of calcification and cystic change within the lesion.

Adult↗
PubMed1987

Hepatoblastoma: radiologic-pathologic correlation in 50 cases.

Fifty cases of hepatoblastoma were reviewed. Virtually all patients were infants or young children with hepatomegaly or a mass. Calcification seen on 11 of 20 radiographs was often in a pattern of small chunks, and eight of these correlated with osteoid formation in histologically mixed hepatoblastomas. Angiography generally showed tumor vascularity, sometimes with a spoke-wheel pattern. Suggestion of tumor nodularity or lobulation on sonography or computed tomography (CT) correlated with the gross appearance. The tumor was usually echogenic and occasionally had small hypoechoic or anechoic areas representing necrosis or hemorrhage. On CT it was usually hypodense, with minimal if any enhancement. The calcification pattern and demonstration of tumor lobulation with septation may help differentiate hepatoblastoma from other liver neoplasms in infants and children under 5 years of age.

Angiography↗