Detection of intestinal ischemia in patients with acute small-bowel obstruction due to adhesions or hernia: efficacy of CT.

OBJECTIVE: The purpose of this study was to determine whether CT can be used to diagnose ischemia of the small intestine in patients with small-bowel obstruction due to adhesions or hernia. SUBJECTS AND METHODS: During a 12-month period, 60 patients underwent surgery for complete or high-grade small-bowel obstruction due to adhesions or hernia, and 29 (48%) had evidence of associated intestinal ischemia. All of these patients had been preoperatively diagnosed by CT as having high-grade small-bowel obstruction. At the same time, a prospective determination was made based on the CT as to whether there was any associated intestinal ischemia. All CT scans were performed within 24 hours of the operation. A CT diagnosis of ischemia was based on the presence of two or more of the following signs: bowel-wall thickening, high attenuation of the bowel wall on unenhanced CT scans, mesenteric edema or fluid, asymmetric bowel-wall enhancement on i.v. contrast-enhanced CT scans, pneumatosis, or portal venous gas. Results of the CT examination and surgical findings were then compared. Further evaluation was done with a retrospective multivariate discriminant analysis. RESULTS: Ischemia was prospectively diagnosed on the basis of CT findings in 41 (68%) of the 60 patients. There were no false-negative CT diagnoses (sensitivity, 100%); however, there were 12 CT diagnoses that were false-positive (specificity, 61%). The multivariate analysis corroborated the prospective results by showing high sensitivity (90%) and diminished specificity (50-64%). Bowel-wall thickening and high attenuation of the bowel wall were the most important signs of ischemia on unenhanced CT scans, whereas abnormal bowel-wall enhancement and mesenteric fluid correlated best on enhanced CT examinations. CONCLUSIONS: CT is a sensitive but not completely specific preoperative indicator of intestinal ischemia in patients with small-bowel obstruction due to hernias or adhesions.

Distinction between postoperative ileus and mechanical small-bowel obstruction: value of CT compared with clinical and other radiographic findings.

OBJECTIVE: The expeditious diagnosis of complete and partial mechanical small-bowel obstruction, as opposed to paralytic ileus, during the immediate postoperative period may be difficult on the basis of clinical and plain film radiographic findings. For this reason, we prospectively evaluated the use of CT in this setting and compared it with the clinical and plain film evaluations as well as with various contrast examinations. SUBJECTS AND METHODS: Thirty-six postoperative patients with signs and symptoms of paralytic ileus or mechanical small-bowel obstruction were examined clinically and had plain abdominal radiographs. Based on the findings of these examinations, the surgeon assigned patients to one of the following categories: (1) paralytic ileus, (2) indeterminate, (3) partial mechanical obstruction, or (4) complete mechanical obstruction. CT scans were obtained within 24 hr of the initial diagnostic studies, and patients were then recategorized according to the above classification solely based on CT findings. Initial examination results were then compared with the CT results. In addition, the results of contrast studies, namely, enteroclysis and barium enema, performed after CT small-bowel series, were evaluated. The gold standard for diagnosis was laparotomy in 20 patients, clinical course and follow-up in 13 patients, and clinical course and contrast studies in the other three patients. RESULTS: CT was effective (sensitivity and specificity, 100%) in distinguishing between postoperative ileus and complete mechanical small-bowel obstruction. The combined clinical and plain film findings were often confusing and nondiagnostic (sensitivity, 19%). CT was also valuable in diagnosing and distinguishing partial mechanical small-bowel obstruction from paralytic ileus. Contrast studies (enteroclysis) in four patients with partial mechanical small-bowel obstruction were useful in grading the degree and severity of the obstruction. CONCLUSION: Our results suggest that in the immediate postoperative period, CT is the method of choice for diagnosing mechanical small-bowel obstruction and distinguishing it from paralytic ileus. Contrast studies are useful in further evaluating partial mechanical small-bowel obstruction.

MR urography: technique and application.

PURPOSE: To evaluate a magnetic resonance (MR) technique for depicting the kidneys and urinary tract. MATERIALS AND METHODS: Fourteen patients with urinary tract obstruction and 20 without obstructions were examined with a modified, heavily T2-weighted fast spin-echo pulse sequence (MR urography). In addition, six healthy volunteers underwent modified MR urography with intravenous administration of furosemide and ureteral compression prior to imaging. RESULTS: MR urography provided high-resolution images of the kidneys and urinary tract in all patients with obstruction with intact collecting systems. Anatomic anomalies were depicted in two patients. Intraluminal neoplasia was well demonstrated in both obstructed and nonobstructed systems (n = 4). Furosemide-enhanced MR urography provided fine anatomic and functional detail of both the kidneys and urinary tract (n = 6). CONCLUSION: MR urography may provide an alternative to more conventional urinary tract imaging techniques. It does not require ionizing radiation or iodinated contrast material. When combined with furosemide and ureteral compression, MR urography provides fine detail and reflects function.

Active pulmonary tuberculosis in patients with AIDS: spectrum of radiographic findings (including a normal appearance).

PURPOSE: To assess the efficacy of chest radiography in the detection of active pulmonary tuberculosis in patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Initial interpretations of chest radiographs of 133 adult patients with AIDS and positive sputum or bronchoalveolar lavage cultures for Mycobacterium tuberculosis were reviewed. Radiographic findings were correlated with CD4 T-cell counts, sputum stains for acid-fast bacilli (AFB), and antituberculous drug sensitivity. RESULTS: Forty-eight (36%) patients had a primary M tuberculosis pattern, 38 (28%) had a postprimary M tuberculosis pattern, 19 (14%) had normal radiographs, 17 (13%) had atypical infiltrates, seven (5%) had minimal radiographic changes, and four (3%) had a miliary pattern. Normal chest radiographs were seen for 10 (21%) of 48 patients with less than 200 T cells per microliter and one (5%) of 20 patients with more than 200 T cells per microliter. Drug sensitivity and sputum staining for AFB did not correlate with radiographic findings. Overall, 19% of cases had multidrug resistance to antituberculous medications. CONCLUSION: Chest radiographs did not suggest active tuberculosis in 43 (32%) of 133 AIDS patients with active pulmonary tuberculosis.

Percutaneous nephrostomy - recovered renal-function in 50 obstetric and gynecologic patients undergoing percutaneous nephrostomy.

Percutaneous nephrostomy (PN) will rapidly correct renal failure due to ureteral obstruction. Complications of the procedure are few and the procedure can be quickly accomplished on an outpatient basis using local anesthesia. A retrospective review of fifty patients who underwent PN led to derivation of a formula which predicts the expected degree of correction of renal function. Measurement of renal intracalyceal pressures at the time of PN was not helpful in predicting-outcome.

Radiographic measures of hyperinflation in clinical emphysema. Discrimination of patients from controls and relationship to physiologic and mechanical lung function.

In a retrospective study we investigated the accuracy of radiographic measurements of hyperinflation in distinguishing a sample of patients with a clinical diagnosis of pulmonary emphysema (n = 44) from a sample of age- and sex-matched control subjects (n = 39). The relationship of the hyperinflation parameters to pulmonary function test results (PFTs) and arterial blood gas measurements (ABGs) in the emphysema patients was also examined. The radiographic measurements were diaphragmatic angle of depression, lung height, lung width, heart size, diaphragm level, radiographic total lung capacity (TLC), and size of the retrosternal air space. By discriminant function analysis, the best contributors to the function were lung height and diaphragmatic angle of depression, followed by radiographic TLC and heart size. The derived classification rule had a diagnostic accuracy of 88 percent. The radiographic measures, largely independent of one another, showed moderate correlations with percentage PFTs, ABGs, portable percentage spirometric studies, height, and weight. High correlations were found between several of the radiographic measurements and the PFTs that represent actual static lung volumes. The correlation between radiographically measured TLC and PFT TLC measured by the helium dilution technique was .90.

The dexamethasone suppression test in depressive, non-depressive and schizoaffective psychosis.

The authors examined the 24-h plasma cortisol response to dexamethasone in 19 patients with co-existing depressive and psychotic features and in 12 non-depressed patients with only psychotic features. The rate and degree of abnormal dexamethasone suppression was greatest in patients who met RDC criteria for primary depressive disorder. Patients who met criteria for schizoaffective--mainly schizophrenic--depressed and other psychotic disorders did not differ from each other in their response to dexamethasone. These data suggest that the DST may have utility in the diagnostic evaluation of some patients with depressive and psychotic features.

Evaluating prolactin response to dopamine agonists in schizophrenia. Methodological problems.

Serum prolactin (PRL) level was assessed after challenges with apomorphine hydrochloride, saline, dopamine hydrochloride, or levodopa-carbidopa (Sinemet) in 19 control and 38 chronic schizophrenic subjects. Baseline PRL level varied inversely with age. High correlations existed between baseline PRL level and any subsequent absolute measure of PRL after administration of a dopamine agonist or placebo. Percent decrease was not a function of baseline concentrations and was therefore the only independent measure of drug response. Baseline PRL level was generally lower during exacerbation than remission in patients studied during two states of illness. Percent PRL level decrease after apomorphine administration was significantly greater in normal subjects than in schizophrenics. Correction of apomorphine responses for corresponding placebo (saline) values abolished differences between groups. Prolactin responses after dopamine or levodopa-carbidopa did not differ; however, placebo correction was not possible.

Clinical utilization of the dexamethasone suppression test.

To explore the procedural nature and clinical impact of the dexamethasone suppression test (DST) in psychiatric hospital practice, case records of 115 consecutive psychiatric inpatients who had undergone overnight DSTs were examined. It was found that clinicians often fail to perform the test according to previously established guidelines and that the results obtained rarely affect clinical psychiatric management in a positive manner.

Effect of hospital admission on DST results.

The authors examined the dexamethasone suppression test (DST) responses of 41 patients with primary major depressive disorder and 40 patients with other psychiatric disorders who were tested within 2-6 days of hospital admission. Significantly more patients with primary depression who were tested on day 2 demonstrated abnormal cortisol suppression than those who were tested on days 3, 4, or 3-6 and than patients with other psychiatric disorders regardless of test day. These results suggest that patients with primary depression may be sensitive to psychophysiologic stresses associated with hospital admission and that the utility of the DST may require further evaluation vis-à-vis the day of DST administration.

Age and the dexamethasone suppression test in depression.

The authors examined the effects of age on plasma cortisol concentrations of 81 depressed men after dexamethasone administration. Dexamethasone nonsuppression was significantly more frequent in patients older than age 55 than those younger. Similarly, older patients had significantly higher postdexamethasone cortisol concentrations than younger patients at all time points sampled. These differences could not be attributed to severity or to the prevalence of psychosis in older and younger depressed patients.

Acetylcholinesterase activity in CSF in schizophrenia, depression, Alzheimer's disease and normals.

Acetylcholinesterase (AChE) activity and protein were measured in the CSF of patients with Alzheimer's disease, depression, schizophrenia with and without tardive dyskinesia, and control subjects. AChE activity was assayed by a radioenzymatic method involving the direct extraction of hydrolyzed 3H-acetate into a toluene-based scintillation fluid followed by liquid scintillation spectrometry. AChE activity was proportional to the amount of CSF protein. Greater than 90% of AChE activity in CSF could be inhibited by 10(-3) M eserine. In addition, activity remained stable despite repeated freeze-thawing in an acetone-dry ice bath. Age was found to be positively correlated with CSF protein and AChE activity expressed per volume CSF, but not with AChE measured per milligram protein. No differences between diagnostic groups were found on either measure of AChE when the extraneous factors of age and CSF protein concentrations were controlled, nor were any differences found between groups for CSF protein when age was controlled.

Statistical power in biological psychiatry.

The use of statistical power and power analysis in both the design and evaluation of experiments in biological psychiatry is described. The possible consequences of low power investigations are discussed, and guidelines are provided to facilitate the application of power analysis. Power curves are provided for sample sizes ranging from 10 to 100 for the Student's t test, and for testing the significance of an obtained Pearson correlation coefficient at both the 0.01 and 0.05 alpha levels. Additionally, difference scales are provided for plasma cortisol and for several neurotransmitter metabolites that are frequently measured in cerebrospinal fluid (CSF). Power evaluation of selected CSF studies measuring neurotransmitter metabolites in depressives and controls suggests the majority had less than a 50% chance of detecting a medium size difference before the experiment was actually performed.

Neuroendocrine and neurochemical measurements in depression.

The authors performed dexamethasone suppression tests (DST), TRH infusions, 72-hour urine collections, and lumbar punctures on a group of male depressed patients. Approximately 60% of the patients were DST positive and 33% had a blunted TSH response. Two biologic variables, the 8 a.m. postdexamethasone cortisol and the postprobenecid CSF 5-hydroxyindoleacetic acid (5-HIAA), accounted for over half of the variance in the behavioral measure, the Hamilton score. Plasma cortisol elevation was associated with high 3-methoxy-4-hydroxyphenyl glycol (MHPG) excretion; TSH blunting was associated with low urinary MHPG excretion. Comprehensive biologic measures showed certain significant interrelationships and correlations with the severity of depression.