Analysis of Changes in Attenuation of Proven Renal Cysts on Different Scanning Phases of Triphasic MDCT

OBJECTIVE

The purpose of this study is to document changes in attenuation values on triphasic MDCT of histologically or surgically proven cystic renal lesions.

MATERIALS AND METHODS

A retrospective study of all renal lesions greater than 1 cm that underwent triphasic MDCT was performed in 90 patients before partial nephrectomy. Three reviewers independently measured the mean attenuation of all lesions in three phases (unenhanced, corticomedullary, and parenchymal) in a blinded retrospective fashion. Forty-three lesions identified at CT in 27 patients had pathologic or surgical confirmation as cysts (fluid-filled lesions). Mean change in attenuation between phases was calculated and correlated with size, unenhanced density, and percentage of the lesion exophytic from renal parenchyma. All scans were obtained after 150 mL of nonionic contrast material was injected at 3 mL/sec. Scanning delays were 30-40 sec (corticomedullary phase) and 120 sec (parenchymal phase).

RESULTS

The mean change in attenuation coefficient of the cysts from the unenhanced to the parenchymal phase was -1.8 H (SD, +/- 4.4 H); from the unenhanced to the corticomedullary phase was -2.3 H (+/- 3.9 H); and from the corticomedullary to the parenchymal phase was 0.6 H (+/- 4.2 H). No cyst increased more than 10 H between the unenhanced and the parenchymal phases; more than 95% of cysts increased less than 8 H between any scanning phases. No significant difference was seen in enhancement related to lesion size (p > 0.054), unenhanced attenuation (p > 0.255), or percentage of the lesion that was exophytic (p > 0.124).

CONCLUSION

The attenuation coefficient of a cystic renal lesion increased by no more than 10 H among the unenhanced, corticomedullary, and parenchymal phase scans.

CT depiction of portal vein thrombi after creation of ileal pouch-anal anastomosis

PURPOSE

To determine the presence and location of portal vein thrombi in patients who have undergone ileal pouch-anal anastomosis (IPAA) and who were scanned with computed tomography (CT).

MATERIALS AND METHODS

During a 4-year period, 92 of 702 patients underwent contrast medium-enhanced CT after a total proctocolectomy with an IPAA. These CT scans were retrospectively reviewed for portal vein thrombus presence, location, and occlusive nature, as well as any accompanying enhancement abnormalities of the hepatic parenchyma. Only 13 patients who had initial CT scans that were positive for thrombi underwent follow-up examinations, and these were reviewed for resolution or progression of the original findings.

RESULTS

Portal vein thrombi were present in 41 (45%) of the 92 patients; 24 (59%) of the 41 were isolated, often multiple, segmental right lobe thrombi. Five patients had both right and left segmental vein involvement. Eleven patients had various combinations of main portal vein, right and left portal vein, or segmental vein thrombi. One patient had an isolated superior mesenteric vein thrombus. Twenty-two of 25 superior mesenteric vein, main portal vein, and right and left portal vein thrombi were nonocclusive, while most (63 of 86) of the segmental vein thrombi were occlusive. Wedge-shaped, peripheral areas of hepatic parenchymal hyperenhancement that were distal to the thrombi were present in 30 (73%) of the 41 patients. Follow-up scans obtained in the 13 patients with portal vein thrombi showed thrombi resolved in five patients, progression to cavernous transformation occurred in one patient, and parenchymal enhancement changes persisted in seven patients. In the seven patients with persistent enhancement changes, four had complete resolution of thrombi.

CONCLUSION

Portal vein thrombi appear to be relatively common after IPAA surgery and are most likely segmental, multiple, and occlusive. Peripheral wedge-shaped areas of hepatic parenchymal hyperenhancement commonly accompany these thrombi.

Imaging of chronic pancreatitis

This article reviews the recognized findings of chronic pancreatitis on CT and endoscopic retrograde cholangiopancreatography. It also discusses more recently developed techniques including gadolinium-enhanced MR imaging, MR cholangiopancreatography, and endoscopic ultrasound. Variants of chronic pancreatitis and difficulties in differentiating pancreatic neoplasms from inflammatory pancreatic masses are also discussed.

Prospective preoperative determination of mucinous pancreatic cystic neoplasms

BACKGROUND

Optimal management of pancreatic cystic neoplasms includes identification and resection of mucinous neoplasms. This study was performed to assess the accuracy of preoperative variables in determining a mucinous lesion.

METHODS

Patients referred for a cystic neoplasm were prospectively assessed by presenting symptoms, blinded radiologic review, and endoscopic ultrasound-guided cyst aspirate analysis. Patients who were symptomatic, or had aspirate findings of a mucinous neoplasm were resected.

RESULTS

Eighty-seven patients were enrolled over a 22-month period ending in December 2001. There were 56 (64%) women and 31 (36%) men, with a mean age of 63 (27-86) years. Thirty-five (40%) patients were resected including 24 (69%) women and 11 (31%) men with a mean age of 58 years. Twenty-eight (80%) patients who had resection were symptomatic. Specimen histology included 18 (51%) mucinous neoplasms, 8 (23%) serous neoplasms, 4 (11%) ductal or neuroendocrine carcinomas, and 3 (9%) pseudocysts. The positive predictive value (PPV) for cyst-aspirate extracellular mucin (83%) was significant in predicting a mucinous neoplasm (P =.009). No other aspirate variables (amylase, carcinoembryonic antigen, CA15-3, viscosity), or patient characteristics were predictive of final histology. Diagnostic agreement between all 3 radiologists was 8% (P =.98). At a median follow-up of 12 months, no patients who were observed required resection.

CONCLUSIONS

Patients with suspected pancreatic cystic neoplasms can be selectively treated on the basis of symptoms and cyst-aspirate mucin analysis. Symptomatic and mucin containing lesions should be resected.

Albumin, steroid hormones and the origin of vertebrates

Albumin, the major serum protein, binds a wide variety of lipophilic compounds including steroids, other lipophilic hormones and various phytochemicals and xenobiotics that bind to receptors for steroids and other lipophilic hormones. Despite albumin's low affinity (K(d) approximately 10(-4) M to 10(-6) M) for these lipophilic compounds, the high concentration of albumin in serum makes this protein a major carrier of steroids and lipophilic hormones and a regulator of their access to receptors. Albumin also functions as a sink for xenobiotics, diminishing the binding of xenobiotics to hormone receptors and other cellular proteins. This protects animals from endocrine disruption by xenobiotics. We propose that these properties of albumin were important in protochordates and primitive vertebrates, such as jawless fish, about 600 to 530 million years ago, just before and during the Cambrian period. It is at that time that the ancestral receptors of adrenal and sex steroids - androgens, estrogens, glucocorticoids, mineralocorticoids, and progestins - arose in multicellular animals. Albumin regulated access of steroids to their receptors, as well as protecting animals from endocrine disruptors, such as phytochemicals, fungal chemicals and phenolics, and other chemicals formed at hydrothermal vents by geochemical processes. Thus, animals in which albumin expression was high had a selective advantage in regulating the steroid response and avoiding endocrine disruption by xenobiotics.

Portal vein thrombi after restorative proctocolectomy

BACKGROUND

Restorative proctocolectomy (RP) has been the surgical procedure of choice for surgical management of mucosal ulcerative colitis since 1978. This study was undertaken to investigate the clinical presentation and implications of portal vein thrombi (PVT).

METHODS

We reviewed all patients undergoing RP in our institution in the 4 years from January 1997 to December 2000. As the diagnosis of PVT was made on computed tomography (CT) scan in all cases, we confined our incidence estimate to those patients having an abdominal CT scan postoperatively. All scans were reviewed by an experienced radiologist. Patient demographics, symptoms, and clinical course were recorded.

RESULTS

A total of 702 patients underwent RP, of whom 94 had a CT scan within the postoperative period. PVT was diagnosed in 42 of the 94 patients (45%). PVT was diagnosed at initial reading of the scan in 11 patients, and on review in 31. The indications for CT scan included abdominal pain, fever, leukocytosis, and delayed bowel function. Septic complications of RP caused these symptoms and signs in 45 patients, 20 of whom had PVT. Twenty-two patients were found to have had PVT without evidence of any septic source.

CONCLUSION

PVT can be found in a high proportion of patients undergoing abdominal CT scan after RP. It is often associated with pain, fever, nausea vomiting, tenderness, and leukocytosis. This study shows that PVT subtle enough to go undiagnosed has no serious consequences, even when not treated. Also, patients treated with anticoagulation recover completely.

Recent insights into the origins of adrenal and sex steroid receptors

The recent cloning by Thornton (2001) of estrogen, progesterone and corticoid receptors from lamprey provides important insights into the early evolution of adrenal and sex steroid receptors and an opportunity to elucidate the ancient steroids that regulated gene transcription. Inclusion of lamprey sequences in a steroid receptor phylogeny indicates that the estrogen receptor is the most ancient of these receptors, followed by the progesterone receptor and the corticoid receptor. Thornton proposed that estradiol was the earliest of the steroids to activate a steroid receptor. An alternative hypothesis is that a steroid in the Delta(5) pathway activated the ancestral estrogen receptor.

Timed barium oesophagram: better predictor of long term success after pneumatic dilation in achalasia than symptom assessment

BACKGROUND

Symptom relief post pneumatic dilation is traditionally used to assess treatment success in achalasia patients. Recently, we showed that symptom relief and objective oesophageal emptying are concordant in about 70% of patients, while up to 30% of achalasia patients report near complete symptom relief despite poor oesophageal emptying of barium.

AIMS

We now report the results of long term clinical follow up in these two groups of achalasia patients, assessing differences in symptomatic remission rates.

METHODS

Achalasia patients undergoing pneumatic dilation since 1995 were evaluated both symptomatically and objectively at regular intervals. Pre and post dilation symptoms were recorded. Barium column height was measured five minutes after ingesting a fixed volume of barium per patient to assess oesophageal emptying. Patients who initially reported near complete symptom relief were divided into two groups based on objective findings on barium study: (1) complete oesophageal emptying (concordant group), and (2) poor oesophageal emptying (discordant group). Patients were followed prospectively for symptom recurrence.

RESULTS

Thirty four patients with complete symptom relief post pneumatic dilation were identified. In 22/34 (65%) patients, the degree of symptom and barium height improvements was similar (concordant group). In 10/34 (30%) patients, there was < 50% improvement in barium height (discordant group). Significantly (p<0.001) more discordant (9/10; 90%) than concordant (2/22; 9%) patients failed therapy at the one year follow up. Seventeen of 22 (77%) concordant patients were still in remission while all discordant patients had failed therapy by six years of follow up. Length of time in symptom remission (mean (SEM)) post pneumatic dilation was significantly (p=0.001) less for the discordant group (18.0 (3.6) months) compared with the concordant group (59.0 (4.8) months).

CONCLUSIONS

(1) Poor oesophageal emptying is present in nearly 30% of achalasia patients reporting complete symptom relief post pneumatic dilation. (2) The majority (90%) of these patients will fail within one year of treatment. (3) Timed barium oesophagram is an important tool in the objective evaluation of achalasia patients post pneumatic dilation.

Enhancement characteristics of papillary renal neoplasms revealed on triphasic helical CT of the kidneys

OBJECTIVE

The purpose of this study was to determine whether renal tumor enhancement or heterogeneity on triphasic helical CT scans is predictive of the papillary cell subtype or nuclear grade of renal cell carcinoma.

MATERIALS AND METHODS

We reviewed the CT scans of 90 consecutive patients with renal masses who had undergone triphasic renal helical CT before a complete or partial nephrectomy (12 with papillary renal cell carcinomas, 66 with nonpapillary renal cell carcinomas, and 12 with benign lesions). Three radiologists who were unaware of the patients' diagnoses retrospectively and independently measured the attenuation of each patient's tumor, abdominal aorta, and normal renal parenchyma on the scans obtained during all three phases. Ratios of tumor-to-aorta enhancement and tumor-to-normal renal parenchyma enhancement were calculated for both of the phases performed after contrast material had been administered. Tumor heterogeneity was calculated as the difference between the highest and lowest attenuation values divided by the value of the enhancement of the aorta. Values were correlated with cell type and nuclear grade found at surgical pathology.

RESULTS

Low tumor-to-aorta enhancement and low tumor-to-normal renal parenchyma enhancement ratios on the vascular phase scans significantly correlated (p < 0.001) with papillary renal cell type carcinoma. Homogeneity and tumor-to-parenchyma enhancement ratios on the parenchymal phase scans also significantly correlated (p < 0.001) with papillary renal cell type carcinoma. Heterogeneity and tumor enhancement ratios did not correlate with the nuclear grade of the carcinoma.

CONCLUSION

Papillary renal cell carcinomas are typically hypovascular and homogeneous. A high tumor-to-parenchyma enhancement ratio (> or = 25%) essentially excludes the possibility of a tumor being papillary renal cell carcinoma. A low tumor-to-aorta enhancement ratio or tumor-to-normal renal parenchyma enhancement ratio is more likely to indicate papillary renal cell carcinoma.

Deletion of 12 carboxyl-terminal residues from pig 3alpha/beta,20beta-hydroxysteroid dehydrogenase affects steroid metabolism

Pig 3alpha/beta,20beta-hydroxysteroid dehydrogenase (3alpha/beta,20beta-HSD) is 80-85% identical to human, rat, and mouse carbonyl reductases. However, pig 3alpha/beta,20beta-HSD contains an extra 12 amino acids at its COOH-terminus that these other mammalian carbonyl reductases lack. We constructed a pig 3alpha/beta,20beta-HSD mutant, G278opal, which lacks these amino acids and found that compared to wild-type 3alpha/beta,20beta-HSD, G278opal has a 10-fold lower catalytic efficiency for testosterone and progesterone. G278opal also has lower 3alpha- and 20beta-reductase and increased 3beta-reductase activity compared to wild-type 3alpha/beta,20beta-HSD. Binding of NADPH to G278opal was similar to that of wild-type 3alpha/beta,20beta-HSD. The recently determined three-dimensional structure of 3alpha/beta,20beta-HSD, without a steroid substrate, shows the 12 COOH-terminal amino acids in a random configuration. Our data indicate that the 12 COOH-terminal amino acids have a role in steroid metabolism suggesting that binding of steroid to wild-type 3alpha/beta,20beta-HSD induces a conformational change in which the 12 COOH-terminal amino acids interact with the steroid substrate.

Radiologic evaluation of the esophagus: methods and value in motility disorders and GERD

The barium esophagram is an essential component in the workup of a patient with dysphagia and gastroesophageal reflux disease, especially when considering antireflux surgery or after such surgery. The examination requires a flexible approach with an emphasis on the motility portion of the examination. When properly performed, the examination should identify the following: normal or impaired esophageal emptying; normal or abnormal motility; the presence and type of hiatal hernia; the presence of a distal stricture or mucosal ring; and in many instances, the presence of gastroesophageal reflux. In patients after antireflux surgery, the examination should identify the following: normal of impaired esophageal emptying; normal or abnormal motility; the location, tightness, and length of the fundoplication; the presence of a recurrent hernia; and the presence of gastroesophageal reflux.

Hydroxysteroid dehydrogenases: ancient and modern regulators of adrenal and sex steroid action

The adrenal and sex steroids receptor clade arose from an ancestral nuclear receptor in a primitive vertebrate at least 540 million years ago during the early Cambrian. At that time, these receptors had less specificity for their canonical ligands than their descendents in mammals have, which raises the question of how specificity for responses to different steroids was regulated. We propose that hydroxysteroid dehydrogenases that metabolized functional groups at different sites on steroids (e.g. C3, C11, C17 and C20) had a key role in providing specificity for steroid regulation of gene transcription in primitive vertebrates. Later, with increased physiological complexity in land animals due to innovations such as the placenta, hydroxysteroid dehydrogenases were recruited for new roles in regulating steroid-mediated physiological responses. Hydroxysteroid dehydrogenases in fish, amphibia and mammals are likely have different affinities for some xenobiotics, which needs to be considered in evaluating their hazards as endocrine disruptors.

Adrenal and sex steroid receptor evolution: environmental implications

The nuclear receptor family responds to a diverse group of ligands, including steroids, retinoids, thyroid hormone, prostaglandins and fatty acids. Previous sequence analyses of adrenal and sex steroid receptors indicate that they form a clade separate from other nuclear receptors. However, the relationships of adrenal and sex steroid receptors to each other and to their ancestors are not fully understood. We have used new information from androgen, estrogen, mineralocorticoid and progesterone receptors in fish to better resolve the phylogeny of adrenal and sex steroid receptors. Sequence divergence between fish and mammalian steroid receptors correlates with differences in steroid specificity, suggesting that phylogeny needs to be considered in evaluating the endocrine effects of xenobiotics. Among the vertebrate steroid receptors, the most ancient is the estrogen receptor. The phylogeny indicates that adrenal and sex steroid receptors arose in a jawless fish or a protochordate and that changes in the sequence of the hormone-binding domain have slowed considerably in land vertebrates. The retinoid X receptor clade is closest to the adrenal and sex steroid receptor clade. Retinoid X receptor is noteworthy for its ability to form dimers with other nuclear receptors, an important mechanism for regulating the action of retinoid X receptor and its dimerization partners. In contrast, the adrenal and sex steroid receptors bind to DNA as homodimers. Moreover, unliganded adrenal and sex steroid receptors form complexes with heat shock protein 90. Thus, the evolution of adrenal and sex steroid receptors involved changes in protein-protein interactions as well as ligand recognition.

Evolution of 17beta-hydroxysteroid dehydrogenases and their role in androgen, estrogen and retinoid action

17beta-Hydroxysteroid dehydrogenases (17beta-HSDs) regulate androgen and estrogen concentrations in mammals. By 1995, four distinct enzymes with 17beta-HSD activity had been identified--17beta-HSD-types 1 and 3, which, in vivo, are NADPH-dependent reductases; and 17beta-HSD-types 2 and 4, which, in vivo, are NAD(+)-dependent oxidases. Since then, six additional enzymes with 17beta-HSD activity have been isolated from mammals. With the exception of 17beta-HSD-type 5, which belongs to the aldoketo-reductase (AKR) family, these 17beta-HSDs belong to the short chain dehydrogenase/reductase (SDR) family. Several 17beta-HSDs appear to be examples of convergent evolution. That is, 17beta-HSD activity arose several times from different ancestors. Some 17beta-HSDs share a common ancestor with retinoid oxido-reductases and have retinol dehydrogenase activity. 17beta-HSD-types 2, 6 and 9 appear to have diverged from ancestral retinoid dehydrogenases early in the evolution of deuterostomes during the Cambrian, about 540 million years ago. This coincided with the origin of nuclear receptors for androgens and estrogens suggesting that expression of 17beta-HSDs had an important role in the early evolution of the physiological response to androgens and estrogens.

Imaging strategies in the pregnant cancer patient

This review summarizes the pertinent issues of radiation exposure to the developing fetus and the existing imaging techniques available to detect neoplastic disease spread of the common malignancies in women of reproductive age (breast cancer, cervical carcinoma, Hodgkin's disease, and melanoma). The standard radiologic work-up for assessing disease extent is reviewed and the pros and cons of these various imaging modalities are discussed with regard to the potential deleterious effects on the mother and fetus. Reasonable alternatives to the standard protocols for documenting extent of disease for these neoplasms are proposed. Usually a pregnant cancer patient can be safely and reasonably staged with imaging. Magnetic resonance (MR) imaging will most often be the procedure of choice because it does not use ionizing radiation. Specialized, focused questions such as sentinel lymph node detection may require limited exposure to ionizing radiation, which will not expose the fetus to a significant dose. While a standard chest x-ray does involve ionizing radiation, it does not expose the fetus to significant radiation.

Timed barium esophagogram: A simple physiologic assessment for achalasia

OBJECTIVE

Success of achalasia therapy is difficult to determine because repeated physiologic study is impractical and symptoms are subjective. Timed barium esophagography directly measures esophageal emptying and is simple to perform. This study (1) evaluates the assessment of myotomy by timed barium esophagography and (2) compares it with premyotomy and postmyotomy symptoms.

METHODS

Fifty patients ingested 250 mL low-density barium and had upright films at 1, 2, and 5 minutes premyotomy. Forty-five underwent repeat timed barium esophagography 8 weeks (median) postmyotomy. Premyotomy and postmyotomy height and width of the barium column were compared and related to symptoms.

RESULTS

At 1, 2, and 5 minutes premyotomy, median barium column height was 19, 17, and 15 cm, and width was 5.2, 4.8, and 4.5 cm, respectively. Surgery reduced these to 7.0, 5.0, and 1.0 cm and to 3.5, 3.0, and 1.0 cm, respectively (P <.001). Postmyotomy complete esophageal emptying was seen in 29%, 36%, and 49% at 1, 2, and 5 minutes. Postmyotomy height was unrelated (r approximately 0.2) to premyotomy height but was directly related to premyotomy width (r = 0.3-0.5; P <.05); postmyotomy width was directly related to premyotomy width (r approximately 0.6; P <.001). Premyotomy dysphagia was more severe when little change in width occurred from 1 to 5 minutes (r = 0.26, P =.07). Premyotomy regurgitation was more severe the higher the barium column (r approximately 0.4, P <.007). Surgery relieved symptoms in the majority of patients (grade 2-5 dysphagia from 72% to 4%, grade 2-5 regurgitation from 79% to 4%). Postmyotomy symptoms were unrelated to the timed barium esophagogram.

CONCLUSIONS

(1) The timed barium esophagogram gives objective confirmation of successful myotomy. (2) Symptoms are unreliable in assessing esophageal emptying.

Feasibility of instructing radiology technologists in the performance of gastrointestinal fluoroscopy

OBJECTIVE

We sought to determine if dedicated gastrointestinal technologists could be trained to properly perform esophagography and double-contrast barium enema examinations.

SUBJECTS AND METHODS

Ninety-four patients undergoing double-contrast barium enema examinations and 123 patients undergoing esophagographic examinations were included in the study. The study was conducted over a 4-month period, with examinations performed by eight gastrointestinal technologists, 10 radiology residents, and four staff radiologists. Four random lists were generated for each set of examinations. Each staff gastrointestinal radiologist, who was unaware of who had performed the examination, independently scored the representative radiographs.

RESULTS

For the double-contrast barium enema examinations, no statistically significant differences were found between the technologists and residents for amount of barium used, degree of distention, cecal opacification, and quality of spot radiographs. The technologist-performed examinations had a statistically significant lower mean fluoroscopy time (3.2 min, compared with 4.0 min for staff radiologists and 5.7 min for residents). For the esophagrams, no statistically significant differences between technologists and residents were found for single-contrast esophagrams; radiographs of the gastric cardia; assessment of motility, reflux, and transit of a solid bolus; and fluoroscopy time. Double-contrast esophagrams obtained by technologists received a better mean score than did those of the residents.

CONCLUSION

Radiology technologists can be trained to perform high-quality esophagography and double-contrast barium enema examinations without an unacceptably high radiation dose.

Mutation of threonine-241 to proline eliminates autocatalytic modification of human carbonyl reductase

Carbonyl reductase catalyses the reduction of steroids, prostaglandins and a variety of xenobiotics. An unusual property of human and rat carbonyl reductases is that they undergo modification at lysine-239 by an autocatalytic process involving 2-oxocarboxylic acids, such as pyruvate and 2-oxoglutarate. Comparison of human carbonyl reductase with the pig enzyme, which does not undergo autocatalytic modification, identified three sites, alanine-236, threonine-241 and glutamic acid-246, on human carbonyl reductase that could be important in the reaction of lysine-239 with 2-oxocarboxylic acids. Mutagenesis experiments show that replacement of threonine-241 with proline (T241P) in human carbonyl reductase eliminates the formation of carboxyethyl-lysine-239. In contrast, the T241A mutant has autocatalytic activity similar to wild-type carbonyl reductase. The T241P mutant retains catalytic activity towards menadione, although with one-fifth the catalytic efficiency of wild-type carbonyl reductase. Replacement of threonine-241 with proline is likely to disrupt the local structure near lysine-239. We propose that integrity of this local environment is essential for chemical modification of lysine-239, but not absolutely required for carbonyl reductase activity.

Adrenal mass evaluation in patients with lung carcinoma: a cost-effectiveness analysis

OBJECTIVE

This study evaluates the cost-effectiveness of various imaging and biopsy strategies for characterizing adrenal masses in patients with newly diagnosed non-small cell carcinoma of the lung.

MATERIALS AND METHODS

A decision-analysis model was used to compare the cost-effectiveness of nine strategies. Initial imaging included unenhanced CT using an adenoma or nonadenoma threshold of 0 or 10 H or in- and opposed-phase MR imaging. When initial imaging did not confirm an adenoma, CT-guided biopsy or subsequent imaging was performed. Medicare reimbursement was used as a surrogate of cost. Net costs were calculated as the difference in costs between two limbs of the decision tree. Net benefits were calculated as the difference between strategies and were calculated for life expectancy in years. MR imaging, CT, and biopsy accuracy, average life expectancy, and surgical mortality rates were based on the literature.

RESULTS

The base case analysis determined that the most cost-effective strategy was CT with an adenoma or nonadenoma threshold of 10 H followed by MR imaging, if necessary. CT with a threshold of 0 H followed by biopsy, if necessary, was the least costly. The incremental cost-effectiveness ratio between these two strategies was $16,370 per year of life gained.

CONCLUSION

Unenhanced CT using a 10 H threshold followed by MR imaging, if needed, was the most cost-effective strategy for evaluating an adrenal mass in a patient with newly diagnosed non-small cell lung cancer.

Knowledge and attitudes of health care social workers regarding advance directives

This cross sectional investigation describes the knowledge and attitudes of health care social workers regarding advance directives and explores factors that influence them. As major contributors to quality patient care, the level of knowledge and attitudes held by health care social workers regarding health care policy mandates are important. Mail survey methods were used to collect data from a systematic random sample (n = 324) of social workers throughout one mid-western state. Results indicate that the majority of health care social workers have high to moderate levels of knowledge about advance directives and hold positive attitudes regarding the policy. Social workers with more experience working with the elderly had higher levels of knowledge. Those employed in nursing homes and hospice settings had more positive attitudes than did those working in other health care facilities.

Esophageal diverticula: patient assessment

Esophageal diverticula are best classified by their anatomic location: pharyngoesophageal (Zenker's diverticula), midthoracic, and epiphrenic. Most diverticula result from esophageal motility disorders. Although some patients are asymptomatic and diverticula are incidental findings, most patients are symptomatic. Dysphagia, regurgitation, and pain are common complaints, however, symptoms are often nonspecific and may be the result of an associated esophageal motility disorder. Contrast radiography is the prime diagnostic tool; evaluation of the diverticulum, associated esophageal abnormalities, and complications are assessed by a barium esophogram. Esophagoscopy adds little to the evaluation of the diverticulum but may be indicated in the assessment of other esophageal abnormalities. Motility studies, which may be difficult or hazardous to perform, are of little use in the diagnosis and treatment of Zenker's diverticula. Manometric evaluation of midthoracic or epiphrenic diverticula usually show an associated motility disorder and may influence treatment decisions.

Midthoracic esophageal diverticula

Periesophageal inflammation, most commonly secondary to tuberculosis, was a frequent cause of midthoracic diverticula. Today, the majority of these diverticula are the result of esophageal motility disorders. Although many patients are asymptomatic, it is the underlying motility disturbances that produce most symptoms. A barium esophagogram is the best study to show midthoracic diverticula. Esophageal manometry may be difficult to perform because of the obstruction of passage of the motility catheter by the diverticulum, but it is useful in defining the cause of the diverticulum and directing therapy. Esophagoscopy is helpful in the assessment of complications or associated esophageal abnormalities. It adds little to the evaluation of the diverticulum. In patients requiring surgery, a diverticulectomy with a myotomy performed on the esophageal wall opposite the diverticulum is the preferred treatment. Lesser procedures have been reported to be successful in select patients.