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.

Comparison of two barium suspensions for dedicated small-bowel series.

OBJECTIVE: The in vivo radiographic features of two commercially available formulations of barium used as contrast media in dedicated small-bowel series were compared. SUBJECTS AND METHODS: Fifty-six consecutive outpatients referred for a dedicated small-bowel series were randomly administered either E-Z-Paque or Entrobar. Representative survey radiographs from each examination were randomized and reviewed by six gastrointestinal radiologists from three institutions. Each observer assigned a numeric score (1 = poor, 2 = fair, 3 = good, and 4 = excellent) that rated the quality of the radiograph with respect to these characteristics: definition of fold pattern, translucency, distention, and integrity of the barium column. Statistical analysis was performed for each characteristic using Wilcoxon's two-sample rank sum test. RESULTS: All six observers found a statistically significant difference between the two barium formulations for mean scores for definition of fold pattern and translucency. Mean scores for fold pattern were 3.3, 3.0, 3.2, 3.6, 3.3, and 3.4 for Entrobar and 2.1, 2.3, 2.4, 3.2, 2.6, and 2.7 for E-Z-Paque. Mean scores for translucency were 2.5, 2.7, 2.8, 3.1, 2.7, and 3.3 for Entrobar and 1.6, 1.7, 2.1, 2.3, 1.9, and 2.7 for E-Z-Paque. No statistically significant difference was found for mean score for distention or integrity of the barium column. CONCLUSION: On radiographs, Entrobar was found to have superior characteristics for visualization of fold pattern and translucency but offered no advantages for distention or integrity of the barium column. Improved translucency and definition of fold pattern may translate into improved sensitivity and confidence in diagnosing small-bowel abnormality.

Pelvic computed tomography of breast carcinoma patients. Should it routinely be added to abdominal computed tomography?

BACKGROUND: This study was conducted to determine if pelvic computed tomography (CT) should routinely be appended to abdominal CT in the workup of patients with breast carcinoma. METHODS: The abdominal-pelvic CTs of 139 breast carcinoma patients (195 exams) were reviewed. Scans were grouped by indication and whether pelvic pathology was known before CT. Pelvic CT results were correlated with their effect on patient management. RESULTS: Among the 119 patients without pre-CT evidence of pelvic disease, a nonosseous pelvic metastasis was identified in only 1; this patient also had liver metastases and management was not changed. No unsuspected pelvic CT finding altered therapy for breast carcinoma. However, three patients underwent surgery for asymptomatic masses discovered on pelvic CT; all were benign. CONCLUSIONS: Pelvic CT is unlikely to affect the management of patients with breast carcinoma by detecting occult metastatic disease.

Power injection of intravenous contrast material through central venous catheters for CT: in vitro evaluation.

PURPOSE: To determine the feasibility of use of a power injector to deliver contrast material through central venous catheters for computed tomographic (CT) examinations. MATERIALS AND METHODS: Ioversol 240 and iothalamate meglumine 43% were separately injected through three 9.6-F Hickman catheters and three 10.0-F Leonard catheters with a power injector in an in vitro study. Flow rates of 1.0, 1.5, 2.0, and 2.5 mL/sec were tested. Peak pressures were mechanically recorded from two sites. A 95% prediction interval was calculated for each peak pressure, and the upper limits at the prediction interval were evaluated to determine if it was less than the recommended limit of 25 psi (175 kPa). RESULTS: Contrast medium, flow rate, and catheter type each statistically significantly affected the measured peak pressures (P = .0001). For each flow rate tested, the upper limits of the prediction interval for the peak pressure at the connection between the coiled tubing and the catheter were below the manufacturer's specified peak pressure. CONCLUSION: In vitro analysis demonstrates that power injection of intravenous contrast medium through central venous catheters does not exceed the pressure limits of these catheters at the flow rates tested. In vivo testing to evaluate the safety and efficacy of power injection through central venous catheters is necessary.

Use of contrast material for spiral CT of the abdomen: comparison of hepatic enhancement and vascular attenuation for three different contrast media at two different delay times.

OBJECTIVE: The purpose of this study was to determine the relative effects of delay time, contrast agent concentration, and contrast agent volume on hepatic enhancement and on aortic and portal vein attenuation for contrast-enhanced spiral CT of the abdomen. The effect of delay time was evaluated by comparing two different delay times for each of three IV contrast media. Three different media were tested to identify whether the effects were different with different iodine concentrations and doses or with different volumes of contrast medium. SUBJECTS AND METHODS: A total of 169 patients who underwent contrast-enhanced CT of the abdomen with spiral CT imaging were evaluated for enhancement of the liver parenchyma and for postenhancement attenuation of the aorta and portal vein. Total iodine doses of 30 g as 100 ml of iohexol 300 or 125 ml of ioversol 240 and of 40 g as 125 ml of ioversol 320 were evaluated at delay times of 45 and 60 sec and with a low-flow monophasic injection at a rate of 2 ml/sec. RESULTS: For each contrast medium tested, a 60-sec delay provided greater hepatic enhancement than did a 45-sec delay (43 vs 32 H for iohexol 300, 37 vs 28 H for ioversol 240, and 50 vs 39 H for ioversol 320; all comparisons, p < or = .0001). The aortic attenuation achieved in the abdomen after contrast medium administration was significantly greater with a 45-sec delay than with a 60-sec delay for iohexol 300 (p = .0290) but not for the other contrast media. The portal vein attenuation achieved after contrast medium administration was significantly greater with a 60-sec delay than with a 45-sec delay for all three contrast media (p = .0051). CONCLUSION: When IV contrast material was injected with a low-flow-rate monophasic bolus, a delay time of 60 sec, longer than that typically used for dynamic incremental scanning, provided greater hepatic enhancement in spiral CT. This result was significant for the three contrast media tested. Aortic attenuation was significantly greater at shorter delay times when a smaller volume of contrast material was injected. Portal vein attenuation was greater at longer delay times, suggesting that the optimal delay time may be longer than 60 sec. Further work to determine the optimal scanning window for hepatic enhancement in spiral CT by use of time-density curves is indicated.

Evaluation of renal masses detected by excretory urography: cost-effectiveness of sonography versus CT.

OBJECTIVE: The purpose of this study was to compare the cost-effectiveness of sonography and CT for the evaluation of renal masses discovered at excretory urography. MATERIALS AND METHODS: The records of 225 patients with a renal mass shown by urography who then had either sonography or CT within 3 months were reviewed retrospectively. The number, location, and size of lesions; initial and subsequent imaging tests; and final diagnoses were determined. Using the current Medicare reimbursements for sonography and CT, we calculated the economic implications of using sonography or CT as the initial examination. Any effect of the location or size of the lesion on the most cost-effective examination was also determined. RESULTS: Twenty-one percent of patients had both initial sonography and follow-up CT because of indeterminate findings or detection of a solid mass that required further staging. When CT was done first, CT findings were equivocal in 12%, necessitating follow-up sonography. At the prevailing charges, CT would have to be needed in 70% of patients initially imaged with sonography to justify the use of CT as the initial examination. The location and size of the lesion did not affect the need for CT at a rate (greater than 70%) that would economically justify use of CT as the first imaging test. Eighty-six percent of patients with a mass detected by urography had either a simple cyst or no evidence of a mass on sonography or CT. CONCLUSION: Sonography is the most cost-effective imaging method for the workup of a renal mass detected at urography. The number of sonographic examinations in which findings are indeterminate or positive (for a solid mass) is not sufficiently high to warrant replacement of sonography by CT, regardless of the size and location of the lesion. CT should be reserved for a limited number of specific indications.

Cystic artery pseudoaneurysm as a complication of laparoscopic cholecystectomy.

A 39-year-old man presented with a subhepatic fluid collection 3 weeks after undergoing a laparoscopic cholecystectomy. This was mistakenly thought to represent an abscess, and a drainage catheter was placed at an outside institution. Upon transfer, the collection was diagnosed as a pseudoaneurysm by spiral computed tomography (CT) and angiography. This is the first report of a pseudoaneurysm complicating laparoscopic cholecystectomy.

Metastasis or adenoma? Computed tomographic evaluation of the adrenal mass.

BACKGROUND: Determining the nature of an adrenal mass is often a clinical challenge. OBJECTIVE: To determine if unenhanced computed tomographic (CT) scanning can differentiate benign adenomas from metastases. METHODS: Twenty-four pathologically proven adrenal masses were retrospectively correlated with their appearance on unenhanced CT scanning. RESULTS: Metastases were significantly larger than adenomas and had higher attenuation coefficients. A sensitivity-to-specificity ratio of 33:100 was achieved at a threshold of 0 Hounsfield units (HU), while a threshold of 10 HU produced a ratio of 58:92. A threshold size of 2.5 cm produced a ratio of 58:100. Attenuation and size were the only useful criteria for differentiating adenomas from metastases. CONCLUSION: Measuring the size and attenuation of adrenal masses can help identify benign adenomas. Lesions exceeding specific thresholds may still be benign and may require biopsy. We advocate documenting lesion stability for longer than is usually done, as one metastatic lesion remained without significant change in appearance for 18 months.

Spiral CT of the abdomen: artifacts and potential pitfalls.

Spiral CT has been advocated as a major advancement in CT technology. Spiral CT scanning is rapid, the volume of IV contrast material can potentially be decreased, and high-quality coronal, sagittal, and three-dimensional reconstruction is possible. However, when compared with dynamic CT, because of the shorter acquisition time of spiral CT, vascular and organ enhancement on spiral CT scans is more dependent on factors that affect the delivery of contrast material into the bloodstream and on the time that scanning begins after the start of injection of contrast material. Additionally, organs other than the liver are scanned earlier than they typically are during a dynamic study, particularly the kidneys and spleen. In our experience to date, these aspects of spiral scanning have led to several difficulties in the interpretation of spiral CT scans. This essay illustrates potential pitfalls in the interpretation of spiral CT scans associated with scanning too soon after injection of contrast material.

Gastrointestinal radiology: current indications and referral patterns.

To determine the current indications and referral patterns for routine gastrointestinal radiology examinations, 1000 consecutive patients were prospectively analyzed. The following specialties were the largest sources of referral: general internal medicine (38%), gastroenterology (21%), and general and colorectal surgery (17%). Referrals from gastroenterologists were weighted toward areas not well evaluated by endoscopy, such as suspected small bowel disease. The major indications for upper gastrointestinal (GI) examinations were dysphagia and swallowing disorders (32%), hiatus hernia/reflux (14%), and ulcer (14%). Small bowel series were predominantly performed for inflammatory bowel disease (37%), obstruction (25%), and occult blood loss (18%). The majority of combined upper GI/small bowel studies were performed for indications primarily relating to the small bowel. Forty percent of barium enemas were performed for detection of neoplasms and polyps, with pain/irritable colon (14%) and exclusion of leak (14%) the next most common indications. Traditional indications, such as peptic ulcer disease and neoplastic disease, continue to be sources of referral for gastrointestinal radiology. However, more specialized applications, particularly in areas not well suited to endoscopy, such as swallowing disorders, inflammatory disease of the small bowel, and evaluation of surgical anastomoses, are also being commonly used. The changing indications, along with the previously documented decreased volume of gastrointestinal radiologic procedures, should be kept in mind when planning a radiology resident educational curriculum.

Hypoechoic renal pyramids: sonographic visualization in older children and young adults.

The frequency and degree of visualization of medullary pyramids in a normal population, aged 10-29 years, was analyzed. Hypoechoic pyramids were visualized in 42% of right kidneys in subjects aged 10-18 years and in 27% of subjects aged 19-29 years. Prominently hypoechoic pyramids, mimicking the appearance of neonatal kidneys, were seen in an additional 34% of subjects aged 10-18 years and in 16% aged 19-29 years. Prominent pyramids were present in 50% of subjects with renal cortical echogenicity (RCE) equal to liver, but also in 21% of subjects with RCE less than liver. Our study expands the age at which prominently hypoechoic medullary pyramids can be considered a normal finding. This may relate to recent improvements in ultrasound technology.

Comparison of iohexol-240 versus iohexol-300 in abdominal CT.

Forty patients without evidence of liver, kidney, or significant cardiac disease were prospectively divided into two groups of 20, receiving either iohexol-240 or iohexol-300. A contrast load of 150 ml was administered in conjunction with a rapid scanning technique at a preselected, fixed level to include liver, renal cortex, and aorta. Peak enhancement was calculated as change in Hounsfield units (HU) over baseline for each area of interest. Mean peak enhancement and standard deviation were calculated for each organ, and the difference between the means for the two contrast agents was compared using the Student's t test. Differences were not statistically significant with all p values greater than 0.05. Our results suggest iohexol-240 is preferred to iohexol-300 for body computed tomography (CT) due to its lower cost and iodine load without statistically significant change in diagnostic quality of the examination.

Fibrotic lesions of the testicle: sonographic patterns mimicking malignancy.

All testicular sonograms performed over a 2.5-year period were retrospectively reviewed, yielding eight patients with pathologically proven lesions consisting primarily of tubular sclerosis and interstitial fibrosis. Only two patients (25%) had a palpable abnormality. A variety of sonographic patterns was found, including focal hypoechoic or hyperechoic lesions and diffuse heterogeneity of the testicular parenchyma. The clinical and sonographic findings prompted open biopsy or orchiectomy in all cases. In the same time period, nine pathologically proven testicular malignancies were evaluated sonographically and displayed either well-defined hypoechoic or diffusely heterogeneous echo patterns. All but two of these patients (78%) had palpable abnormalities. This study demonstrates a significant overlap in the sonographic appearance of benign fibrotic lesions and testicular malignancies. When careful palpation of a sonographically heterogeneous or focal hypoechoic lesion fails to reveal a mass and serum tumor markers are negative, an open biopsy with frozen section analysis should be considered rather than proceeding directly to orchiectomy. Homogeneously hyperechoic masses can be considered benign and do not require surgery.

CT evaluation of wall thickening in the alimentary tract.

Computed tomography (CT) of the alimentary tract, when performed with adequate distention of the organ being examined and in the true axial plane, provides valuable information about the intramural or extramural extent of pathologic conditions. Neoplastic, vascular, and inflammatory diseases can all result in wall thickening of the alimentary tract. Wall thicknesses greater than 5 mm in the esophagus, stomach, and colon and 4 mm or greater in the small bowel are considered abnormal. If the thickened wall has a target or double-ringed appearance, it is most likely caused by benign disease. In general, the CT findings of asymmetric or focal wall thickening, nodularity, and thickening greater than 1.5 cm suggest a malignant process. Although it is commonly associated with benign disease, diffuse thickening can also result from some infiltrating malignant diseases. Careful review of CT scans for evidence of metastatic disease and adenopathy and correlation with clinical information aid in the differential diagnosis.

Abdominal desmoids: CT findings in 25 patients.

Desmoids are histologically benign but locally aggressive fibrous tumors. Although overall they are rare lesions, they are a common manifestation of Gardner syndrome. We retrospectively reviewed clinical records and CT scans of 25 patients with abdominal desmoids. The number, location, and CT characteristics of the lesions were recorded for each patient. Tumors were solitary in 72% of patients and multiple in 28%. Fifty percent were located in the abdominal wall, 41% in the mesentery, and 9% in the retroperitoneum. More than two thirds of the lesions had well-defined borders, with the remainder displaying an infiltrative outer margin. The majority of tumors had attenuation values equal to (47%) or greater than (41%) the attenuation of muscle on contrast-enhanced CT scans. Complications attributable to the desmoid were commonly detectable on CT (hydronephrosis occurred in 36% and small-bowel obstruction in 20%). Our results detail the spectrum of CT findings and complications caused by abdominal desmoids.

Abdominal lymphadenopathy: spectrum of CT findings.

Many malignant processes cause abdominal lymphadenopathy, and computed tomography (CT) has become the primary modality for its detection. Diagnosis of lymphadenopathy is facilitated by optimal imaging techniques and a knowledge of the various nodal chains, their complex interconnections, and preferential pathways of spread. Optimal techniques include imaging after oral administration of adequate amounts of barium suspension and dynamic scanning after intravenous administration of contrast material with an infusion pump. Although such techniques help prevent misdiagnoses due to normal and anomalous vascular structures, other benign diseases can mimic the CT appearance of malignant lymphadenopathy. The authors emphasize a regional approach for the diagnosis of lymphadenopathy, according to the groupings of retrocrural, retroperitoneal, gastrohepatic ligament, porta hepatis, celiac and superior mesenteric artery, pancreaticoduodenal, perisplenic, mesenteric, and pelvic lymph nodes. Lymphadenopathy is defined as retrocrural nodes greater than 6 mm in short axis, upper abdominal nodes greater than 10 mm, and pelvic nodes greater than 15 mm.

The insensitivity of sonography in the detection of choledocholithiasis.

To determine the sensitivity of sonography in the detection of choledocholithiasis, the sonograms of 138 patients with surgically proven common bile duct stones were reviewed. A definite diagnosis of choledocholithiasis could be made on the basis of the sonograms in 22% of cases. Overall, 23% had common ducts of normal caliber (less than or equal to 7 mm diam) and 23% had normal total bilirubin levels at the time of the examination. Although a sonographic diagnosis of choledocholithiasis provides important information for the surgeon, the method is not sufficiently sensitive to serve as a definitive preoperative test for common bile duct stones.