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Biomedical subjects

D H Stephens

Publications and source records attributed to D H Stephens.

At least 37 records · Page 2Linked to original sources
PubMed1990

Islet cell tumors in von Hippel-Lindau disease: increased prevalence and relationship to the multiple endocrine neoplasias.

Von Hippel-Lindau disease is a rare, autosomal-dominant disorder characterized by CNS hemangioblastomas, retinal angiomas, renal cell carcinomas, pheochromocytomas, and visceral cysts. The occurrence of islet cell tumors in von Hippel-Lindau disease has been noted recently. Because of the coexistence of both islet cell tumors and pheochromocytomas in some patients with this disorder, it has been proposed that there may be a continuum of the multiple endocrine neoplasias. However, no large, multifamily study has been published evaluating the prevalence of islet cell tumors and pheochromocytomas in von Hippel-Lindau disease. To assess the frequency of islet cell tumors in this disorder and its relationship to the multiple endocrine neoplasias, we reviewed the clinical and imaging findings of all patients with von Hippel-Lindau disease evaluated at the Mayo Clinic between January 1979 and December 1989. Forty-three patients with von Hippel-Lindau disease from over 25 kindreds were found. Cross-sectional imaging of the pancreas had been performed in 35. Islet cell tumors were found in six (17%) of these, three islet cell adenomas and three islet cell carcinomas. No patient presented with endocrine-related symptoms; four tumors were detected during screening examinations of the abdomen. Two (33%) of these six patients had a coexisting pheochromocytoma. Our review of a large number of patients from many different families with von Hippel-Lindau disease revealed a high prevalence of islet cell tumors and the frequent coexistence of islet cell tumors and pheochromocytomas. This latter finding supports a continuum of the multiple endocrine neoplastic syndromes.

Adenoma, Islet Cell↗
PubMed1989

Computed tomography of the large bowel and appendix.

Computed tomography (CT) of the colon is useful in assessment of patients with colonic disease because the entire bowel wall, extraluminal tissues, and adjacent solid organs can be directly visualized. Patients with advanced stage colorectal carcinoma can be reliably identified with CT. This information can assist in surgical planning for intraoperative irradiation and placement of a hepatic artery infusion catheter. CT is an important imaging modality in the postoperative evaluation for recurrent rectal cancer after abdominoperineal resection. CT-guided biopsy often can provide histologic proof of suspected tumor recurrence or metastasis. Patients with diverticulitis or appendicitis can be identified by CT. The extent of disease and the nature of the inflammatory process--factors potentially affecting patient management--can be directly visualized. Percutaneous aspiration and drainage of abscess collections can be curative in appropriately selected patients.

Appendicitis↗
PubMed1989

Chronic pancreatitis: reassessment with current CT.

A retrospective analysis was performed of contrast material-enhanced current-generation computed tomographic (CT) examinations in 56 patients with documented chronic pancreatitis. Dilatation of the main pancreatic duct was seen in 68% of cases, parenchymal atrophy in 54%, pancreatic calcifications in 50%, fluid collections in 30%, focal pancreatic enlargement in 30%, biliary ductal dilatation in 29%, and alterations in peripancreatic fat or fascia in 16%. The relatively small proportion of examinations in which no abnormalities were observed, 7%, differs from that in early reports, as does the absence of generalized pancreatic enlargement. Pancreatic ductal dilatation and parenchymal atrophy were notably more prevalent than reported previously. Nine of the 17 patients with focal pancreatic enlargement had calculi within the mass, which suggested benign disease; of the eight other patients, two of whom had coexistent carcinoma, this finding was absent and the masses were considered indeterminate at CT.

Chronic Disease↗
PubMed1989

CT-guided biopsy: prospective analysis of 1,000 procedures.

The authors prospectively analyzed 1,000 biopsies guided with computed tomography (CT) and performed in 955 patients over a 30-month period. All patients were followed up from 3 months to 2 years. The biopsies were performed in an average of 22 minutes (range, 3-85 minutes) by 26 different radiologists; five radiologists performed 547 of the procedures. Of the 1,000 biopsies, 722 were performed in areas in the liver, retroperitoneum, pancreas, pelvis, and adrenal glands. Of 69 errors in diagnosis, 67 were falsely negative and two were falsely positive; 747 true-positive and 184 true-negative diagnoses were made. CT-directed biopsy for accurate diagnosis was 91.8% sensitive and 98.9% specific, with a positive predictive value of 99.7% and a negative predictive value of 73.3%. Of 11 patients with complications, seven had hematomas, three had pneumothorax, and one had hematuria. No deaths occurred, and only one patient required surgery.

Adrenal Glands↗
PubMed1989

Biliary cystadenoma and cystadenocarcinoma: CT and sonographic findings.

Biliary cystadenomas and cystadenocarcinomas are rare cystic neoplasms, usually intrahepatic in location, that are characterized pathologically by a multilocular appearance. We report the CT and sonographic findings in eight cases of biliary cystadenoma and three cases of biliary cystadenocarcinoma and correlate them with the surgical and pathologic findings. CT showed internal septa in eight of the 10 multiloculated lesions, whereas sonography showed septa in all five cases in which it was used. CT in two of the three cystadenocarcinomas showed thick and coarse mural and septal calcifications as well as large solid soft-tissue masses in one. CT showed mural soft-tissue nodules in the single case of a unilocular cystadenocarcinoma. Sonography and CT usually show the multilocular nature of biliary cystadenomas and cystadenocarcinomas. The presence of mural or septal nodules, discrete soft-tissue masses, and possibly thick and coarse calcifications increase the likelihood of a cystadenocarcinoma.

Adult↗
PubMed1988

Imaging of fibrolamellar hepatocellular carcinoma.

The imaging studies of 12 patients with fibrolamellar hepatocellular carcinoma were reviewed in an attempt to characterize the appearance of the tumors and to stage them. The imaging studies showed that 10 (83%) of 12 tumors were solitary, one was multilobulated with several satellite nodules, and one was bilobed. Surface lobulations were present in nine (82%) of 11 tumors on CT, five of five on sonography, and seven (88%) of eight on angiography. A central scar was identified in five (45%) of 11 tumors on CT, three (60%) of five on sonography, and two (25%) of eight on angiography. Calcification was seen in six (55%) of 11 tumors on CT, four (80%) of five on sonography, and one (13%) of eight on plain films. The tumors were correctly staged as resectable or nonresectable by CT in eight (73%) of 11 patients, by sonography in four (80%) of five, and by angiography in five (63%) of eight. Understaging was responsible for all but one of the staging errors. Distinguishing fibrolamellar hepatocellular carcinoma from more common hepatocellular carcinoma can affect surgical planning and survival.

Adolescent↗
PubMed1988

Cystic pancreatic tumors: CT and sonographic assessment.

Thirty-five CT scans and 23 sonograms of 45 pathologically proved pancreatic cystic neoplasms (16 microcystic adenomas, 17 mucinous [macrocystic] cystadenomas, and 12 mucinous [macrocystic] cystadenocarcinomas) in 43 patients were retrospectively and blindly reviewed. Radiologic findings and their usefulness in differentiating microcystic from mucinous subtypes were assessed. The number of cysts within the tumors (more than six in microcystic adenomas and six or fewer in mucinous cystadenomas and cystadenocarcinomas) and the diameter of the majority of cysts within the tumor (less than or equal to 2 cm in microcystic adenomas and greater than 2 cm in mucinous tumors) were the most helpful radiologic findings in differentiating tumor types. Calcification was present in 38% of microcystic adenomas, 18% of mucinous cystadenomas, and 8% of mucinous cystadenocarcinomas by CT. Calcification was not definitely identified on any of the sonograms. A central scar was identified in only two (13%) of 16 microcystic adenomas. Blind retrospective review was often able to correctly classify tumors as either microcystic (CT, 93%; sonography, 78%) or mucinous (CT, 95%; sonography, 93%). All tumors with a typical appearance on either CT or sonography were categorized correctly. Cystic pancreatic tumors may be difficult to prospectively separate from other types of pancreatic cysts. Assuming a cystic neoplasm is present, it often can be classified correctly as microcystic or mucinous (macrocystic) by using the above criteria.

Adenoma↗
PubMed1986

Computed tomography and ultrasonography of hepatoma.

Computed tomography (CT) scans and sonograms of 37 patients with hepatocellular carcinoma (hepatoma) were reviewed to determine the characteristics of the tumour and to compare the modalities in terms of accuracy in defining tumour morphology and ability to predict vascular invasion and extrahepatic spread. By CT, slightly over 50% of the tumours were multicentric, about 40% were solitary, and the rest were diffuse. About half of the hepatomas were heterogeneous in density before injection of contrast agent and most became enhanced in a non-uniform manner. In addition, about a quarter of the tumours either became visible or were better seen after injection of contrast agent. At sonography, approximately two-thirds of the neoplasms were thought to be solitary and one-third multicentric. The majority also had a mixed echo texture. Although the lesion was identified in all 13 patients who had both studies, sonography underestimated the extent of hepatic involvement in 38% of the cases. Sonography also failed to demonstrate lymphadenopathy that was detected by CT in two patients. In general, both techniques were effective in identifying vascular invasion. CT was very accurate in showing the extent of hepatic involvement but was unable to identify direct invasion of neighbouring structures. Because each technique has limitations in the evaluation of hepatoma, we believe that both should be performed if curative resection is being considered.

Adult↗
PubMed1985

Focal nodular hyperplasia and hepatic adenoma: comparison of angiography, CT, US, and scintigraphy.

The authors reviewed 23 cases of focal nodular hyperplasia and 13 cases of hepatic adenoma, all of which were confirmed pathologically. All solitary masses that exhibited normal or increased uptake of technetium 99m-sulfur colloid were shown to be hyperplasia; while previous criteria such as a central blood supply on angiograms or a central scar on computed tomography (CT) or ultrasound (US) scans were helpful, they were relatively infrequent. A mass that was slightly hypodense and homogeneous on a CT or US scan and highly vascular with an intense capillary stain on an angiogram was almost always hyperplasia. Acute hemorrhage within a focal hepatic tumor was common in adenoma but did not occur in hyperplasia.

Adenoma↗
PubMed1985

Magnetic resonance imaging of hemorrhage.

The magnetic resonance imaging (MRI) characteristics of evolving hemorrhage are discussed and compared with those of computed tomography (CT). Studies of 15 hematomas were undertaken in four mongrel dogs. The hematomas were created by the injection of autologous blood into the subcutaneous tissues of the thigh. The hematomas were studied serially with both MRI and CT. Pulse sequences included spin-echo (2100 msec TR, 40 and 80 msec TE) and inversion-recovery (2100 msec TR, 400 msec TI, 40 msec TE). Relaxation times (T1 and T2) were calculated in each case. CT values (H) were also obtained. In addition, 24 single and 14 serial scans of hemorrhage were obtained from 24 patients. MRI was performed on a 0.15-T resistive magnet scanner. T1 and T2 relaxation times and CT values decreased as the hematomas resolved. T1 and T2 relaxation times of intraparenchymal hemorrhage tended to remain elevated with time. MRI seems to be more sensitive than CT for the detection of hemorrhage, primarily because of superior contrast resolution.

Adolescent↗