Technical cost of radiologic examinations: analysis across imaging modalities.

PURPOSE: To determine the individual technical costs of general diagnostic radiographic, ultrasonographic (US), computed tomographic (CT), magnetic resonance (MR) imaging, and scintigraphic examinations and interventional radiology. MATERIALS AND METHODS: The Radiology Cost and Productivity Benchmarking Study method of the University HealthSystem Consortium, a cooperative group of academic medical centers, was modified and extended to the six imaging modalities in a tertiary care academic setting. Hospital billing and cost records were analyzed for fiscal year 1996. Costs were divided into labor and nonlabor categories and were allocated to individual imaging modalities on the basis of resources consumed. Physician cost and hospital overhead were not included. Unit costs were analyzed per technical relative value unit (RVU) and per examination. RESULTS: The costs per technical RVU for diagnostic radiography, US, CT, MR imaging, scintigraphy, and interventional radiology were $65. 06, $28.74, $20.95, $17.69, $42.19, and $89.03, respectively. The technical costs per examination for diagnostic radiography, US, CT, MR imaging, scintigraphy, and interventional radiology were $41.92, $50.28, $112.32, $266.96, $196.88, and $692.60, respectively. CONCLUSION: The method of unit cost analysis for individual imaging modalities was successfully tested in a tertiary care setting. The method should be adopted to allow cost comparison across many institutions, which will permit the promotion of best practices.

Can academic radiology departments become more efficient and cost less?

PURPOSE: To determine how successful two large academic radiology departments have been in responding to market-driven pressures to reduce costs and improve productivity by downsizing their technical and support staffs while maintaining or increasing volume. MATERIALS AND METHODS: A longitudinal study was performed in which benchmarking techniques were used to assess the changes in cost and productivity of the two departments for 5 years (fiscal years 1992-1996). Cost per relative value unit and relative value units per full-time equivalent employee were tracked. RESULTS: Substantial cost reduction and productivity enhancement were realized as linear improvements in two key metrics, namely, cost per relative value unit (decline of 19.0% [decline of $7.60 on a base year cost of $40.00] to 28.8% [$12.18 of $42.21]; P < or = .001) and relative value unit per full-time equivalent employee (increase of 46.0% [increase of 759.55 units over a base year productivity of 1,651.45 units] to 55.8% [968.28 of 1,733.97 units]; P < .001), during the 5 years of study. CONCLUSION: Academic radiology departments have proved that they can "do more with less" over a sustained period.

Effect of patient position on sonographically measured renal length in neonates, infants, and children.

OBJECTIVE: Renal length as measured on sonography is fundamental in the evaluation of renal disease in children. Understanding the effect of patient position and imaging plane on measured renal length is important for the appropriate use of the standards for interpretation. The goal of this study was to determine how measurement of renal length on sonograms is affected by changes in patient position and imaging plane. SUBJECTS AND METHODS: One hundred seventy-six neonates, infants, and children who were 2 days to 17 years old underwent sonography froin October 1995 through June 1996. The largest long-axis renal dimension in sagittal, coronal, and prone planes was obtained for each kidney. Data were analyzed separately for each kidney to determine the individual variation of renal length. RESULTS: The correlation between maximum renal length on coronal, sagittal, and prone sonograms was greater than .95 for both right and left kidneys. The coronal plane yielded the largest measured renal length and the prone view, the smallest. The median of the absolute value of the differences between individual renal lengths as measured on sonograms in the different imaging planes was 2-3 mm for both left and right kidneys (mean difference, left kidney = 3.34-3.62 mm; mean difference, right kidney = 3.22-3.68 mm). CONCLUSION: The coronal and sagittal views yield the longest measurements and prone views, the shortest. Therefore, initial measurements should be made in coronal or sagittal planes. Prone views should be reserved for situations in which the suspicion exists that the kidney was foreshortened on other views. Reference standards done in a particular plane should be applicable in most situations regardless of the patient position necessary to obtain optimum length.

Intraluminal colon pressure dynamics with Valsalva maneuver during air enema study.

PURPOSE: To determine the effects of the Valsalva maneuver on intraluminal colon pressure during air enema studies. MATERIALS AND METHODS: Air enema studies were performed in four adult volunteers, and intraluminal colon pressure measurements were recorded with a high-speed electronic strip chart and aneroid gauge methods. One hundred thirty-five Valsalva maneuvers were produced with open- and closed-glottis maneuvers, with varying degrees of straining, and during normal peristalsis. RESULTS: Valsalva pressure waves are discrete waveforms that can be distinguished from baseline insufflation and normal peristaltic waves. Valsalva waves are of both simple and complex types. The range of peak Valsalva pressures was 12-148 mm Hg. Average mild, moderate, and vigorous pressures with a closed glottis were 22, 38, and 90 mm Hg, respectively. High pressures (120-130 mm Hg) were observed with open- and closed-glottis maneuvers. CONCLUSION: Valsalva maneuvers increase intracolonic pressure 12-148 mm Hg above baseline pressure. Valsalva pressure waves are discrete and can be accurately detected with both aneroid and electronic transducer systems.

Achievement of substantial cost reduction through joint purchasing by the radiology departments of a large vertically integrated health care system.

RATIONALE AND OBJECTIVES: The authors sought to lower costs by coordinating the purchase of equipment, supplies, and services in the radiology departments of a vertically integrated health system formed by the merger of two of the largest academic medical centers in New England. METHODS: The radiology departments at Massachusetts General Hospital and Brigham & Women's Hospital formed a cost-reduction task force to explore opportunities to jointly decrease costs. Data from the operating budgets of both institutions were collected and analyzed to find specific items within the budgets that could yield substantial cost savings. RESULTS: The project's first phase yielded over $810,000 in reduced costs from a system-wide annual budget of only $7 million for film and contrast material. Ongoing additional projects suggest that longer term contracts that contain steeper discounts with a decreased number of vendors will result in further decreases in the cost of materials and supplies. CONCLUSION: Coordination of purchasing by the radiology members of an integrated delivery system can yield substantial savings.

Radiographic appearance of follicular bronchitis in children.

OBJECTIVE: The purpose of this study was to present the first radiographic description of a newly described disease in children, follicular bronchitis. MATERIALS AND METHODS: We retrospectively reviewed the medical history and radiographs of eight children with biopsy evidence of follicular bronchitis. RESULTS: All eight infants had findings on initial radiographs that were consistent with viral inflammatory disease. The clinical features of follicular bronchitis started by 6-8 weeks old and peaked between about 2 and 3 years old. After several months of the disease, the infants' radiographs showed a more obvious interstitial pattern. When these children were approximately 3 years old, the radiographic findings began to return to normal. Four children have been followed up for at least 8 years. By that age, the clinical symptoms of respiratory disease have disappeared. All four children tested after they were 8 years old had abnormal results of pulmonary function tests. CONCLUSION: The combination of unique clinical features associated with the radiographic appearances we describe should allow radiologists to suggest the diagnosis of follicular bronchitis.

Can clinical parameters help reliably predict the onset of acute intracranial hemorrhage in infants receiving extracorporeal membrane oxygenation?

PURPOSE: To determine whether clinical parameters can be used to help predict the onset of acute intracranial hemorrhage (ICH) in infants receiving extracorporeal membrane oxygenation (ECMO). MATERIALS AND METHODS: The authors retrospectively reviewed cranial sonograms and intensive care unit data for 53 neonates treated with ECMO for intractable cardiorespiratory insufficiency. Thirty-nine boys and 14 girls were treated between February 1988 and June 1993. Gestational age ranged from 34 to 43.5 weeks (mean, 39.2 weeks). Birth weights ranged from 2,200 to 4,650 g (mean, 3,310 g). Multiple clinical variables were subjected to statistical analysis. RESULTS: There were 38 patients without ICH, 10 with early ICH (within 72 hours after cannulation), and five with late ICH (more than 72 hours after cannulation). Analysis with bivariate scatterplots revealed almost complete overlap in the clinical parameters for patients in these three categories. Thus, use of individual variables to predict acute ICH was impractical. CONCLUSION: No clinical parameters helped adequately distinguish patients who developed ICH from those who did not.

Pseudomembranous colitis: CT findings in children.

A spectrum of nodular haustral thickening and an accordion pattern have been reported as specific features of pseudomembranous colitis (PMC) in adults. A retrospective review of nine patients with PMC was performed to assess whether this spectrum of CT findings also occurred in children. In four girls and five boys, CT scans were performed within 3 days of a positive stool toxin assay for Clostridium difficile. Documented CT abnormalities included nodular haustral thickening, the accordion pattern, colonic wall thickening, ascites, and pericolonic edema. These results were then correlated as to their impact on the clinical outcome. Circumferential colon wall thickening was identified in 7/9 (78 %) patients (mean thickening 14.5 mm). Nodular haustral thickening was identified in 4/9 (44 %) and the accordion pattern in 2/9 (22 %). Other findings included pericolonic edema in 3/9 (33 %) and ascites in 1/9 (11 %). Wall thickening was confined to the left colon and rectum in 2/9 (22 %), to the right colon in 2/9 (22 %), and involved the whole colon in 3/9 (33 %). Although CT findings associated with PMC in children may be suggestive for this diagnosis, CT is less specific than laboratory and clinical findings.

Intracolonic pressure measurements during hydrostatic and air contrast barium enema studies in children.

PURPOSE: To prospectively evaluate intraluminal pressure changes in the colon of children undergoing conventional hydrostatic (barium and water-soluble contrast material) and air contrast barium enema studies. MATERIALS AND METHODS: Dynamic intracolonic pressure was measured in 26 children undergoing hydrostatic barium (23% wt/vol) enema studies, air contrast barium enema studies, or water-soluble contrast material enema examinations. Measurements were obtained with a measuring device capable of recording rapid changes in pressure. Pressure measurements were obtained with the contrast reservoir system open (contrast material was free to run through the tubing into the patient's colon) and closed (tube was clamped). RESULTS: The colonic pressures during the filling phase with liquid contrast material were equal to those elsewhere at the same level with the hydrostatic system. Mean pressure ranged from 30 to 50 mm Hg with peaks of more than 100 mm Hg during Valsalva maneuvers. During air contrast barium enema studies, sharp pressure increases and rapid swings in the intracolonic pressure occurred during and after manual insufflation of air. CONCLUSION: During conventional hydrostatic barium enema studies, intracolonic pressures remain low. During air insufflation, there were intermittent high, sharp pressure peaks.

Autosomal recessive polycystic kidney disease: long-term sonographic findings in patients surviving the neonatal period.

OBJECTIVE: We studied the sonographic findings and the changes in renal function seen on long-term follow-up of children who had the initial diagnosis of autosomal recessive polycystic kidney disease made in the neonatal period. MATERIALS AND METHODS: The case records and sonograms of 14 children with biopsy evidence of autosomal recessive polycystic kidney disease were evaluated. Nine children who survived the neonatal period were followed up for a mean of 13 years (range, 5-19 years) after diagnosis and form the basis of this study. Serial changes in renal size, echogenicity, and function were assessed sonographically. The imaging findings were compared with those described in published reports. RESULTS: The sonographic findings showed that five of the nine children had a decrease in renal size, and three had stable renal size over a minimum follow-up period of 5 years. Only one of the nine survivors showed progressive increase in renal size. All had increased cortical echogenicity and large kidneys. Three patients showed a subjective change in renal echogenicity over time. A change in the echogenic pattern to one that resembles autosomal dominant polycystic kidney disease was noted with no evidence of increase in size of the kidneys. None of the surviving children had renal stones or massively enlarged kidneys. The renal function of seven of the nine survivors has remained stable with creatinine clearance nearly normal (> 60 ml/min/1.73 m2), and there was no correlation between renal size and renal function. CONCLUSION: In patients with autosomal recessive polycystic kidney disease who survive the neonatal period, kidney size as seen on sonograms does not continue to increase despite the patients' linear growth and maintained normal renal function. Rather, a decrease in kidney size and change in echogenicity occurs, producing a pattern that is similar to that seen on sonograms of patients with autosomal dominant polycystic kidney disease but without the marked increase in kidney size that occurs in that entity. This changing cystic pattern on follow-up sonograms may be the reason that previous descriptions of the sonographic findings in cases of autosomal recessive polycystic kidney disease have varied and why a decrease in size may not herald deteriorating renal function.

Application of wavelet compression to digitized radiographs.

OBJECTIVE: Image data compression is an enabling technology for teleradiology and picture archive and communication systems. Compression decreases the time and cost of image transmission and the requirements for image storage. Wavelets, discovered in 1987, constitute a new compression technique that has been described in radiologic publications but, to our knowledge, no previous studies of its use have been reported. The purpose of this study was to demonstrate the application of wavelet-based compression technology to digitized radiographs. MATERIALS AND METHODS: Twelve radiographs with abnormal findings were digitized, compressed, and decompressed by using a new wavelet-based lossy compression algorithm. Images were compressed at ratios from 10:1 to 60:1. Seven board-certified radiologists reviewed images on a two-headed, high-resolution (2K x 2K) diagnostic workstation. Paired original and compressed/decompressed images were presented in random order. Reviewers adjusted contrast and magnification to judge whether image degradation was present, and if so, whether it was of diagnostic significance. Quantitative error measures were tabulated. RESULTS: Reviewers found no clinically relevant degradation below a compression ratio of 30:1. Skeletal radiographs appeared more sensitive to compression than did chest or abdominal radiographs, but the trend was not statistically significant. Quantitative error measures increased gradually with compression ratio. CONCLUSION: On the basis of subjective assessment of image quality and the computational efficiency of the algorithm, wavelet-base techniques appear promising for the compression of digitized radiographs. The results of this initial experience can be used to design appropriate observer performance studies.

The role of emergent arteriography in penetrating limb trauma.

Routine arteriographic evaluation of patients with penetrating trauma in proximity to major limb arteries has been declining in popularity. Although some controversy still exists, management based on clinical examination alone has been advocated for those without overt signs of vascular injury. To better identify the need for invasive radiologic intervention, 453 limbs (394 patients) sustaining gunshot, shotgun, and stab wounds (331, 28, and 94, respectively) in proximity to a major artery underwent angiography from 1984 through 1990. An arterial injury was demonstrated in 37 (9.4%) of 394 limbs, with a normal vascular examination, but only eight (2.0%) were deemed to require operative intervention. By comparison, 45 (76%) of 59 patients with an abnormal vascular examination (diminished/absent peripheral pulses or decreased Doppler-derived limb blood pressures) had an arterial injury demonstrated by arteriography, with 33 (55.9%) undergoing operative repair. The presence of an associated long bone fracture increased the incidence of angiographically demonstrated vascular injury, but operative intervention was only increased for those with an abnormal vascular exam. A detailed physical examination including Doppler-derived limb blood pressures is essential. In the presence of a normal vascular exam, routine arteriography for proximity of injury is unnecessary. Arteriography should be reserved to identify those few patients with an abnormal vascular examination and an unclear injury who may require vascular repair.

Barium extravasation discovered some years after pyloromyotomy.

Two children who had surgery for pyloric stenosis are presented. Each had an unusual density discovered on an abdominal plain radiograph taken at least a year after surgery for pyloric stenosis. Subsequent investigation showed that this density represented barium from the preoperative contrast studies that had apparently leaked into the soft tissues at the time of surgery but was not recognized at that time. This unusual complication has not been previously reported but could potentially be fairly common. Unnecessary diagnostic testing could be avoided by recognition that this complication does occur.

The futility of the chest radiograph in the febrile infant without respiratory symptoms.

OBJECTIVE: Major pediatric textbooks advocate a chest radiograph as part of the diagnostic evaluation for a sepsis workup for febrile infants less than 3 months old. Very few studies have addressed the value of performing a chest radiograph in this situation. Two studies previously published lack the numbers to statistically justify a conclusion about the need to perform a chest radiograph in the febrile infant. METHODS: Evaluated were 197 febrile infants 3 months old or less with a history, physical examination, chest radiograph, and other laboratory studies to determine the cause of their fever. This group of infants was combined with the group of infants from two similar studies published previously in the literature using cumulative meta-analysis. The combined group resulted in 617 infants. RESULTS: The combined group of infants had 361 infants who had no clinical evidence of pulmonary disease on history or physical examination. All 361 infants had normal chest radiograph. These results gave a 95% confidence interval that the chance of a positive chest radiograph in a patient with no pulmonary symptoms would occur less than 1.02% of the time. CONCLUSIONS: The generally advocated policy of obtaining a chest radiograph as part of the sepsis workup in febrile infants should be discontinued, and chest radiographs should be obtained only in febrile infants who have clinical indications of pulmonary disease.