Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy: prospective comparison.

BACKGROUND: The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests. METHODS: Patients with faecal occult blood, haematochezia, iron-deficiency anaemia, or a family history of colon cancer underwent three separate colon-imaging studies--ACBE, followed 7-14 days later by CTC and colonoscopy on the same day. The primary outcome was detection of colonic polyps and cancers. Outcomes were assessed by building an aggregate view of the colon, taking into account results of all three tests. FINDINGS: 614 patients completed all three imaging tests. When analysed on a per-patient basis, for lesions 10 mm or larger in size (n=63), the sensitivity of ACBE was 48% (95% CI 35-61), CTC 59% (46-71, p=0.1083 for CTC vs ACBE), and colonoscopy 98% (91-100, p<0.0001 for colonoscopy vs CTC). For lesions 6-9 mm in size (n=116), sensitivity was 35% for ACBE (27-45), 51% for CTC (41-60, p=0.0080 for CTC vs ACBE), and 99% for colonoscopy (95-100, p<0.0001 for colonoscopy vs CTC). For lesions of 10 mm or larger in size, the specificity was greater for colonoscopy (0.996) than for either ACBE (0.90) or CTC (0.96) and declined for ACBE and CTC when smaller lesions were considered. INTERPRETATION: Colonoscopy was more sensitive than other tests, as currently undertaken, for detection of colonic polyps and cancers. These data have important implications for diagnostic use of colon imaging tests.

Imaging primary and metastatic cancer of the liver.

Either CT or MRI can be used as a primary screening test for liver masses in a patient with a known or suspected malignancy. A number of variations in techniques are available for both CT and MRI, and combinations of these techniques are often required to increase the detectability rate for hepatic lesions. Whether CT or MRI is chosen as an initial screening technique depends upon the particular patient and the institution. After a liver lesion has been identified, attempts should be made to obtain a specific diagnosis. Certain liver masses may have a specific CT appearance, especially when they are calcified. With some benign lesions a specific diagnosis is possible using imaging techniques, and in these instances CT and a supplemental radionuclide study may be of complimentary value. These include cavernous hemangioma, focal fatty liver, and focal nodular hyperplasia. Another group of lesions have a CT or an MRI appearance that is suggestive for a specific diagnosis, but may require confirmation with a biopsy or other tests. These include hepatoma, which may present as a mass with portal vein thrombosis, hepatic adenoma, which may appear as a mass with central hemorrhage, focal nodular hyperplasia may occur as a mass with a central stellate scar (on CT), or a cavernous hemangioma, which fulfills specific CT or MRI criteria. A final group of lesions consists of masses without a characteristic or suggestive CT or MRI appearance. These lesions will require biopsy for final diagnosis.

Esophageal cancer.

The important concepts of carcinoma of the esophagus are reviewed in this article. Pathology of malignant esophageal tumors is described and tumor behavior of squamous cell carcinoma is discussed and illustrated. Various classifications and staging methods are reviewed with emphasis placed on the TNM system. The role of current imaging techniques in patients with esophageal carcinoma is presented. Computed tomography is discussed and illustrated in detail. The relative cost effectiveness of these procedures is presented and an imaging approach emphasizing TNM staging is described for patients with known carcinoma of the esophagus. This imaging approach is integrated with the basic aspects of treatment and both curative and palliative pathways are presented. The final section of the article deals with these same concepts in patients with carcinoma of the gastroesophageal junction. The important differences between adenocarcinoma of the gastroesophageal junction and esophageal carcinoma are described.

Delayed detection of coarctation in infancy: implications for timing of newborn follow-up.

During a recent 5-year period, 74 patients younger than 6 months of age were diagnosed with coarctation of the aorta. Coarctation was correctly diagnosed in only 22% of patients prior to referral despite readily apparent femoral pulse abnormalities in 86%. Infants whose symptoms were detected between 5 and 14 days of age were significantly more ill than infants outside this age range and had a high mortality rate (25%). The number of associated cardiac defects was not related to the severity of clinical illness in this group, suggesting that closure of the ductus arteriosus is the primary determinate of disease severity. Observations in two patients suggested that a detectable pulse discrepancy occurs between 3 and 5 days postnatally. Upper extremity hypertension was found commonly in infants after 5 days of age despite the presence of congestive heart failure. Earlier detection of coarctation in the newborn requires a diligent cardiovascular and peripheral pulse examination between 3 and 7 days of life, upper extremity and lower extremity blood pressure measurement, and a high index of suspicion.

Postoperative irradiation for tonsillar carcinoma.

From January 1975 through July 1987 at the Mayo Clinic, 16 patients received postoperative adjuvant radiation therapy for squamous cell carcinoma of the tonsil (pathologic stage I in 4 patients, stage III in 3, and stage IV in 9). Follow-up was continued for a minimum of 2 years or until death. At 5 years, overall survival was 74% and disease-free survival was 68% for the entire group of patients. The local-regional control rate at 5 years was 83% for 12 patients with pathologic stage III or IV disease; the 5-year disease-free survival rate was 74%. The results with use of postoperative irradiation for stage III or IV tonsillar cancer seem superior to those for a similar historical group of patients who underwent surgical treatment only. Because the number of patients was small and the analysis was retrospective, our study may have included some undetected bias.

Hemophilus influenzae purulent pericarditis in children: diagnostic and therapeutic considerations.

Purulent pericarditis is an unusual complication of infection in infancy and has been associated with an extremely high mortality rate. Early diagnosis followed by combined antibiotic therapy and surgical drainage of the pericardium has markedly improved survival. Between APril, 1975, and February, 1979, nine patients with purulent pericarditis secondary to Hemophilus influenzae type B were treated at the Oklahoma Children's Memorial Hospital. In every case signs and symptoms of congestive heart failure were present, and a pericardial effusion was demonstrated by echocardiography and confirmed by pericardiocentesis. The organism was identified with countercurrent immunoelectrophoresis and antibiotic sensitivity determined by rapid beta lactamase assay. All patients were treated with a combination of parenteral antibiotics and open surgical drainage of the pericardium. There were no deaths and all patients demonstrated marked improvement following operation. Follow-up echocardiography revealed no evidence of pericardial effusion or signs of constriction in any patient.

Computed tomographic staging of gastrointestinal tract malignancies. Part I. Esophagus and stomach.

The utility and limitations of CT staging of carcinomas of the esophagus, stomach, small bowel, and colon are reviewed. Routine preoperative staging of esophageal carcinoma is recommended because of CT's sensitivity of more than 90% in detecting mediastinal invasion and a specificity of more than 85% in collected series. We recommend the use of CT as a problem-solving technique rather than as a routine preoperative test in patients with gastroesophageal junction, and gastric and small bowel malignancies. Routine use of CT to stage colorectal carcinomas also does not seem justifiable, due to the inability of CT to determine the depth of bowel wall involvement and to detect tumor in normal size lymph nodes. CT can help differentiate tumors that invade the pelvic side walls from more limited cancers and, therefore, in certain cases can aid in therapy planning. CT is the best method for detecting local recurrence in patients with rectosigmoid carcinomas.

Contrast media tonicity. Part I. Effects upon IV-DSA time-concentration curve peak and width: experimental studies.

Prior to the formation of an intravenous digital subtraction angiography (IV-DSA) image, contrast medium passes through the lesser circulation and is diluted by the blood volume of the heart and lungs. If the contrast medium alone influences central blood volume or cardiac output, the shape of the resultant time-concentration curve may be degraded. To the extent that contrast medium tonicity reduces curve peak or increases width, image quality for mask mode IV-DSA will suffer. To quantify the effect of contrast medium tonicity upon curve shape, contrast medium (1) at increasing iodine concentration and increasing osmolality and (2) at constant iodine concentration and increasing osmolality was injected into the right atria of mongrel dogs. In both experiments, increasing osmolality was associated with an increase in central blood volume (CBV) and cardiac output. With an increase in CBV, curve peak fell. With an increase in both CBV and cardiac output, curve width was not influenced by increasing osmolality. The effect of osmolality upon CBV was highly variable; in these experiments CBV was influenced more by subject-to-subject variability. However, on the average, higher tonicity contrast media produced curves with lower peaks. These studies suggest that isotonic contrast medium does not increase CBV and that isotonic contrast medium is preferable to hypertonic contrast medium for IV-DSA image formation.

Transcatheter electrocoagulation of the pulmonary artery: an experimental model in dogs for studying pulmonary thrombosis.

Transcatheter electrocoagulation (TCEC) has been shown to produce permanent arterial occlusion. This study was performed to evaluate the potential of using TCEC of the pulmonary artery as an experimental model of pulmonary thromboembolism. Fourteen lobar or first-order pulmonary arteries were occluded in ten dogs in the acute studies. Eight pulmonary arteries were occluded in eight dogs that were sacrificed 25 to 85 days after TCEC. There were permanent occlusions in seven, and all seven evidence of pulmonary infarction. The animals tolerated the procedure well. The technique may have merit as an experimental model for studying pulmonary thrombosis and infarction.

High-resolution multiplanar CT images of the larynx.

The standard technique for computed tomographic evaluation of the larynx utilizes 5-mm contiguous transaxial sections. Multiplanar images reformatted with these sections have not been of clinical use. We have evaluated the practicality of utilizing coronal and sagittal reformatted images produced from contiguous 1.5-mm transaxial sections. The technique of rapid sequential scanning with automatic table incrementation allows 36 contiguous thin section scans to be acquired in less than 9 minutes. Phantom studies showed a marked improvement in spatial resolution with thin section reconstructions. Preliminary clinical evaluation shows visualization of smaller structures with improved edge definition of both low- and high-contrast structures.

CT differentiation of pleural effusion from ascites. An evaluation of four signs using blinded analysis of 52 cases.

Four criteria have been described to differentiate ascites from pleural effusion by computed tomography (CT). These four signs (the diaphragm sign, the displaced crus sign, the interface sign, and the bare area sign) were compared in a retrospective blinded analysis in 52 patients with ascites, right pleural effusion, or both ascites and right pleural effusion. There were limitations with each of the four criteria. Each of the individual criteria was reliable when only one abnormal fluid collection, either pleural effusion or ascites, was present. When both a right pleural effusion and ascites were present, none of the four criteria reliably identified both fluid collections. The combined use of the four criteria, however, led to a correct identification of all the abnormal fluid collections.

Evaluation of embolization distal to arterial occlusion by transcatheter electrocoagulation (TCEC) and Gianturco coils.

A technique was developed to evaluate the degree of embolization distal to arterial occlusion by transcatheter electrocoagulation (TCEC) and Gianturco coils. The kidneys of mongrel dogs were used to collect emboli distal to conventional TCEC or Gianturco coil occlusion of the renal arteries. TCEC controls (TCEC setup without current), normal kidneys, kidneys embolized with autologous clot, and kidneys whose renal arteries were surgically ligated were evaluated for comparison. The renal vasculature was flushed and then fixed by glutaraldehyde infusion. The kidneys were filled with a barium gelatin mixture and examined both radiographically and pathologically. The four normal kidneys and the four ligated kidneys gave a characteristic complete filling of the vascular web, while filling defects were evident in the following conditions: 3/12 TCEC controls; 26/34 with TCEC occlusion; 6/10 with Gianturco coils; and 11/11 with autologous clot. An excellent correlation existed between radiographic intraluminal filling defects and grossly and microscopically identified emboli.

The mechanism of transcatheter electrocoagulation (TCEC).

This study was performed to evaluate the temperature, pH change, and electrolysis products at the anode during transcatheter electrocoagulation (TCEC). Stainless steel and platinum anodes insulated by standard angiographic catheters were placed in renal dialysis tubing. The tubing, filled with either saline solution or plasma, was placed in a water bath (25 degrees C) containing a cathode. Temperature was recorded at the tip of the anode, placed in saline solution, using 15 ma for 20 minutes (n = 5 for each wire and current). pH was measured during applications of 15, 30, and 60 ma for 20 minutes (n = 6 for each current, anode, and solution). The solutions were analyzed for products of electrolysis. The temperature remained constant. The pH declined to 1.5 +/- .3 (mean +/- SEM) with the platinum electrode and to 2.5 +/- .5 with the stainless steel anode. Metallic elements and oxygen were the electrolysis products recovered from the stainless steel experiments. Chlorine gas was the major product recovered from the platinum studies. These results confirm that during TCEC there is no thermal injury. The pH change at the anode is probably a major mechanism in TCEC. Different types of reactions take place at platinum and stainless steel anodes, which may account for differences between TCEC with these two electrodes.

Factors in the intestinal absorption of oral cholecystopaques.

Interest in the pharmacokinetics of cholecystopaques initially centered on transport from blood to bile. The data obtained in this effort have been valuable and have shown that the maximal iodine concentration achievable in the bile is quite similar for all of the currently available compounds. This concentration is, of course, dose dependent. the transport of contrast material from the bowel to the blood has been shown to be quite variable. Considerable progress was made in understanding this. The tremendous differences in absorption of iopanoic acid depending upon the pH of the administered solution was an initial revelation. The development of the concept that there is a water layer through which the cholecystopaque must pass before reaching the lipid membrane of the intestinal cell has added clarity to understanding the difference in absorption between water-soluble and water-insoluble cholecystopaques. A complete knowledge of what might enhance or inhibit absorption is not known. There is beginning to be an understanding of how intestinal dose relates to plasma levels. This should lead to an optimal dose-timing scheme for each cholecystopaque. The basic assumption is that the highest iodine concentration in the gallbladder leads to the most accurate cholecystography. If this is true, the gallbladder needs to be offered bile at the maximum concentrations during the period preceding filming. To accomplish this, the appropriate plasma level necessary for maximum excretion is needed. Experimental data suggest that our current clinical methods in regard to dose and dose timing need revision to optimize cholecystography. This revision needs to take place with a careful look at toxicity. Accepting the present premise that oral cholecystography can be improved, perhaps without a significant increase in morbidity, a fundamental question to be asked is: is it worth it?

Effect of B-15,000 (Iopamidol), a new nonionic contrast agent, on cardiac function of the isolated rat heart.

The isolated rat heart model was used to examine the effect of a new nonionic contrast agent, B-15,000 (Iopamidol), on cardiac function. Comparative studies were performed with Amipaque, Renografin 60, Renografin 76, and Vascoray. The three ionic contrast agents had significantly greater detrimental effects on cardiac function than either nonionic agent. The results support the continued evaluation of the nonionic agents for use in coronary angiography.

Transcatheter electrocoagulation: a therapeutic angiographic technique for vessel occlusion.

Previous work has shown that localized electrocoagulation of blood vessels using direct current applied by catheter placed electrodes is feasible. In vitro and in vivo experiments showed that clot size and thrombosis of vessels are directly related to the product of the amount and duration of the current. Surgically created splenic hemorrhage was well controlled in 9 of 10 animals. The vessels remained permanently occluded after electrocoagulation in 8 of 9 animals. Pathological studies of all the vessels showed intimal damage at the sites of occlusion. These experiments indicate that clot formation may be a product of both intimal damage and platelet attraction to the positive electrode. The technique has advantages over embolization since no foreign material is injected and a localized clot is produced at the tip of the guidewire. There are certain disadvantages and further refinements must be developed to establish transcatheter electrocoagulation as a useful clinical technique for vessel occlusion.

Effect of iopanoate on the biliary and urinary excretion of iodipamide.

The effect of sodium iopanoate and iopanoic acid on the biliary excretion of iodipamide in dogs was studied. Enteric administration of sodium iopanoate within one hour of iodipamide infusion reduced biliary iodipamide excretion and increased urinary iodipamide output. The biliary and urinary excretion of iodipamide was not influenced by iopanoic acid administered 40 and then again 16 hrs before iodipamide. These results suggest that iodipamide cholangiography can be employed 16-18 hrs after a standard two-day iopanoic acid oral cholecystogram without decreasing the ability to visualize the biliary ductal system or increasing the urinary iodipamide excretion.

Experimental pulmonary infarction in dogs: a comparison of chest radiography and computed tomography.

Transcatheter electrocoagulation of the pulmonary artery was used to successfully create experimental pulmonary infarcts in 15 to 16 dogs. The animals were evaluated from one to 13 weeks by chest radiography, computed tomography (CT), angiography, and pathologic examination. The abnormal densities in the dogs' lungs cleared in two to three weeks. The majority of the chest radiographs were normal in two weeks, and all were normal after three weeks. Prior to sacrifice, CT showed abnormal densities in the lungs in only two of eight animals. CT proved to be more sensitive than chest radiography for showing the densities in the lungs due to pulmonary infarction.

Effect of increasing current and decreasing blood flow for transcatheter electrocoagulation (TCEC).

Arterial occlusion by direct-current transcatheter electrocoagulation (TCEC) has been developed experimentally and used successfully in clinical situations. The major shortcoming of the technique has been the lengthy time necessary for occlusion of larger arteries. In the present study we attempted to decrease the time necessary for TCEC occlusion of the renal and femoral arteries of heparinized mongrel dogs. The results showed that the occlusion time could be significantly decreased, either by increasing the TCEC current from 15 ma to 30 or 60 ma, or by using a Meditech balloon catheter to occlude the artery during TCEC. The combination of higher current and simultaneous balloon occlusion consistently produced permanent occlusion of arteries up to 7 mm in diameter in 15 minutes or less. Balloon occlusion with TCEC is significantly faster than without this modification and makes the technique of TCEC more applicable for human use and for continued experimental study than any previous refinements.

Digital radiographic evaluation of the bile ducts.

This study compares digital radiographic images of the bile ducts in dogs with images obtained using routine radiography. The dogs were infused with iodipamide (2 ml/minute for 30 minutes), and the bile ducts were imaged at 60 minutes using plain radiograph and five digital techniques: (1) dual-energy, (2) DSA-hybrid prepixel shift, (3) DSA-hybrid postpixel shift, (4) a dual-energy film system--Digirad, and (5) scan projection radiography using hybrid subtraction. Six radiologists who were not familiar with digital radiography evaluated the six different studies. The images were presented in a randomized order and each image was evaluated on a five-point scale. There was no difference between the plain radiographs and the dual-energy images. Both of these studies were rated significantly better (P less than .001) than the other four digital images. These results suggest that digital radiography during direct cholangiography may be easily accomplished using a 10% to 15% iodine solution.