Pulmonary embolism at CT angiography: implications for appropriateness, cost, and radiation exposure in 2003 patients.

Radiology. 2010 Aug;256(2):625-32

Authors: Mamlouk MD, vanSonnenberg E, Gosalia R, Drachman D, Gridley D, Zamora JG, Casola G, Ornstein S

PURPOSE: To determine whether thromboembolic risk factor assessment could accurately indicate the pretest probability for pulmonary embolism (PE), and if so, computed tomographic (CT) angiography might be targeted more appropriately than in current usage, resulting in decreased costs and radiation exposure. MATERIALS AND METHODS: Institutional review board approval was obtained. Electronic medical records of 2003 patients who underwent CT angiography for possible PE during 1(1/2) years (July 2004 to February 2006) were reviewed retrospectively for thromboembolic risk factors. Risk factors that were assessed included immobilization, malignancy, hypercoagulable state, excess estrogen state, a history of venous thromboembolism, age, and sex. Logistic regressions were conducted to test the significance of each risk factor. RESULTS: Overall, CT angiograms were negative for PE in 1806 (90.16%) of 2003 patients. CT angiograms were positive for PE in 197 (9.84%) of 2003 patients; 6.36% were Emergency Department patients, and 13.46% were inpatients. Of the 197 patients with CT angiograms positive for PE, 192 (97.46%) had one or more risk factors, of which age of 65 years or older (69.04%) was the most common. Of the 1806 patients with CT angiograms negative for PE, 520 (28.79%) had no risk factors. The sensitivity and negative predictive value of risk factor assessment in all patients were 97.46% and 99.05%, respectively. All risk factors, except sex, were significant in the multivariate logistic regression (P < .031). CONCLUSION: In the setting of no risk factors, it is extraordinarily unlikely (0.95% chance) to have a CT angiogram positive for PE. This selectivity and triage step should help reduce current costs and radiation exposure to patients.

PMID: 20551182 [PubMed - indexed for MEDLINE]

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Triple-lumen peripherally inserted central catheter in patients in the critical care unit: prospective evaluation.

Radiology. 2010 Jul;256(1):312-20

Authors: Trerotola SO, Stavropoulos SW, Mondschein JI, Patel AA, Fishman N, Fuchs B, Kolansky DM, Kasner S, Pryor J, Chittams J

PURPOSE: To prospectively evaluate outcomes associated with use of a triple-lumen (TL) peripherally inserted central catheter (PICC) in the intensive care unit (ICU) setting. MATERIALS AND METHODS: Patients were prospectively enrolled in this HIPAA-compliant, institutional review board-approved study. Informed consent was obtained. All patients were in one hospital’s ICUs and needed intermediate-term central venous access requiring three lumina. A 6-F tapered TL PICC was placed by a bedside nursing-based team with backup from the Interventional Radiology department. Placement complications, as well as long-term complications, were recorded. At catheter removal, ultrasonography (US) of the veins containing the TL PICC was performed to detect occult venous thrombosis. Regardless of indication for removal, catheters were sent for culture to detect colonization. RESULTS: The study was stopped prematurely after 50 of a planned 167 patients were enrolled when a scheduled interim analysis detected a venous thrombosis rate that was considered unacceptably high by the study oversight committee (thrombosis was symptomatic in 20% of patients [10 of 50]). Venous thrombosis (symptomatic or asymptomatic) was detected in 26 of 45 patients (58%; 95% confidence interval [CI]: 43%, 72%) examined with US. Documented catheter-related bloodstream infection did not occur (0%; 95% CI: 0%, 7%); colonization was detected in three of 29 catheter tips sent for culture (10%; 95% CI: 2%, 27%). Catheter malfunction and dislodgment occurred in one patient each. CONCLUSION: The TL PICC design used in this study resulted in unacceptably high venous thrombosis rates. Even when used in a high-risk setting for infection (ie, the ICU), rates of clinically evident infection and colonization were absent and low, respectively.

PMID: 20574104 [PubMed - indexed for MEDLINE]

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Management of the incidental renal mass.

Radiology. 2008 Oct;249(1):16-31

Authors: Silverman SG, Israel GM, Herts BR, Richie JP

Despite substantial advances in the imaging-based diagnosis of renal masses, the increased detection of incidental renal masses with cross-sectional imaging poses problems to the radiologist and referring physician. Most incidental renal masses can be diagnosed with confidence and either ignored or treated without further testing. However, some renal masses, particularly small ones, remain indeterminate and require a management strategy that is both medically appropriate and practical. In this article, the literature will be reviewed and an approach to the diagnosis and management of the incidental renal mass will be suggested. Management recommendations, derived from data regarding the probability of malignancy in cystic and solid renal masses, are provided for two types of patients, those in the general population and those with limited life expectancy or co-morbidity. The Bosniak classification is used to guide the management of cystic masses, with observation reserved for selected patients, and the presumption of benignity recommended for simple-appearing cystic masses smaller than 1 cm. Among solid renal masses, a more aggressive overall approach is taken. However, additional imaging, and in selected patients, percutaneous biopsy, is recommended to diagnose benign neoplasms. Although additional studies are needed to establish risks and benefits, observation of solid masses may be considered in selected patients. Minimally invasive treatments of renal cancer (including percutaneous ablation) show promise but at the same time challenge the radiologist to review the approach to the incidental renal mass.

PMID: 18796665 [PubMed - indexed for MEDLINE]

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Acute appendicitis: meta-analysis of diagnostic performance of CT and graded compression US related to prevalence of disease.

Radiology. 2008 Oct;249(1):97-106

Authors: van Randen A, Bipat S, Zwinderman AH, Ubbink DT, Stoker J, Boermeester MA

PURPOSE: This study was a head-to-head comparison of graded compression ultrasonography (US) and computed tomography (CT) in helping diagnose acute appendicitis with an emphasis on diagnostic value at different disease prevalences, commonly occurring in various hospital settings. MATERIALS AND METHODS: MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched from January 1966 to February 2006. Prospective trials were selected if they (a) compared graded compression US and CT in the same patient population; (b) included more than 10 patients, otherwise, the study was considered a case report; (c) evaluated mainly adults or adolescents; (d) used surgery and/or clinical follow-up as reference standard; and (e) reported data to calculate 2 x 2 contingency tables for graded compression US and CT. Estimates of sensitivity, specificity, and positive and negative likelihood ratios (LRs) for US and CT were calculated. Posttest probabilities after CT and US were calculated for various clinically relevant prevalences. RESULTS: Six studies were included, evaluating 671 patients (mean age range, 26-38 years); prevalence of acute appendicitis was 50% (range, 13%-77%). Positive LR was 9.29 (95% confidence interval [CI]: 6.9, 12.6) for CT and 4.50 (95% CI: 3.0, 6.7; P = .011) for US, yielding posttest probabilities for positive tests of 90% and 82%, respectively. Negative LR was 0.10 (95% CI: 0.06, 0.17) for CT and 0.27 (95% CI: 0.17, 0.43) for US (P = .013), resulting in posttest probabilities of 9% and 21%, respectively. Posttest probabilities for positive tests were markedly decreased at lower prevalences. CONCLUSION: In head-to-head comparison studies of diagnostic imaging, CT had a better test performance than did graded compression US in diagnosing appendicitis. Ignoring the relationship between prevalence (pretest probability) and diagnostic value may lead to an inaccurate estimation of diagnostic performance.

PMID: 18682583 [PubMed - indexed for MEDLINE]

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Incidence of nephrogenic systemic fibrosis at two large medical centers.

Radiology. 2008 Sep;248(3):807-16

Authors: Prince MR, Zhang H, Morris M, MacGregor JL, Grossman ME, Silberzweig J, DeLapaz RL, Lee HJ, Magro CM, Valeri AM

PURPOSE: To determine the incidence and associated risk factors of nephrogenic systemic fibrosis (NSF) in patients who undergo gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: Institutional review board approval was obtained for retrospective review of the medical records from two hospitals to identify all cases of biopsy-confirmed NSF and all patients administered a GBCA from January 1, 1997, to June 30, 2007. Informed patient consent was not required. The incidence of NSF was calculated for patients who received a standard dose of GBCA, patients who received a high dose, and subgroups of patients with renal impairment. RESULTS: Fifteen patients developed NSF after gadolinium-enhanced MR imaging. All of them had an estimated glomerular filtration rate (eGFR) lower than 30 mL/min, and 11 had acute renal failure or acute deterioration of chronic renal failure. The incidence of NSF after gadolinium-enhanced MR imaging without screening for renal function was zero of 74,124 patients with the standard dose of GBCA and 15 (0.17%) of 8997 patients with the high dose (P < .001). The NSF incidence associated with a high dose of GBCA increased to 0.4% in patients in a chronic hemodialysis program and to 8.8% in those who had an eGFR lower than 15 mL/min but were not undergoing hemodialysis (P < .001). The NSF incidence in the patients with acute renal failure who received a high dose when their creatinine level was increasing was 19% (11 of 58 patients) when hemodialysis was delayed for longer than 2 days. More patients with NSF had proinflammatory events, and compared with patients without NSF, these patients had lower pH, younger age, lower eGFR, elevated serum phosphorus levels, and a longer delay between GBCA injection and hemodialysis. CONCLUSION: For patients with an eGFR lower than 15 mL/min, hemodialysis helped to prevent NSF. For patients with an eGFR lower than 30 mL/min who received a high dose of GBCA, acute renal failure, delayed hemodialysis after contrast agent injection, proinflammatory events, and hyperphosphatemia were associated with increased risk of NSF.

PMID: 18710976 [PubMed - indexed for MEDLINE]

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Risk of nephrogenic systemic fibrosis: evaluation of gadolinium chelate contrast agents at four American universities.

Radiology. 2008 Sep;248(3):799-806

Authors: Wertman R, Altun E, Martin DR, Mitchell DG, Leyendecker JR, O’Malley RB, Parsons DJ, Fuller ER, Semelka RC

PURPOSE: To retrospectively determine the benchmark incidence of nephrogenic systemic fibrosis (NSF) related to the confirmed use of different gadolinium chelate contrast agents at four U.S. university tertiary care centers. MATERIALS AND METHODS: Institutional review board approval was obtained for this HIPAA-compliant multi-institutional study; the requirement for informed patient consent was waived. Patients who had a diagnosis of NSF between January 2000 and December 2006 were identified at four tertiary care centers with renal transplant and dialysis services. A standard checklist was used to acquire reliable data from the four centers. The diagnosis of NSF was confirmed histopathologically in all patients. The association of NSF development with gadolinium chelate contrast agent administration in each patient was assessed. The type and cumulative dose of contrast agent administered to each patient with NSF were determined at each center by using the standard checklist. The benchmark incidence of NSF was determined and expressed as the ratio of the number of patients with NSF who had undergone gadolinium chelate-enhanced magnetic resonance (MR) imaging, relative to the total number of patients who underwent gadolinium chelate-enhanced MR imaging at each tertiary care center. Benchmark incidences of NSF were compared among the four centers by using Fisher exact tests. RESULTS: Gadodiamide was used at University of North Carolina at Chapel Hill (center A) and Emory University (center B), and gadopentetate dimeglumine was used at Wake Forest University (center C) and Thomas Jefferson University (center D) during the study period. Twenty-three patients at center A, nine patients at center B, three patients at center C, and one patient at center D had NSF and had undergone gadolinium chelate-enhanced MR imaging. The incidence of NSF was one in 2913 patients who underwent gadodiamide-enhanced MR examinations and one in 44,224 patients who underwent gadopentetate dimeglumine-enhanced MR examinations. CONCLUSION: The benchmark incidence of NSF was much greater at the two centers where gadodiamide was used than at the two centers where gadopentetate dimeglumine was used.

PMID: 18632533 [PubMed - indexed for MEDLINE]

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Evaluation of a “triple rule-out” coronary CT angiography protocol: use of 64-Section CT in low-to-moderate risk emergency department patients suspected of having acute coronary syndrome.

Radiology. 2008 Aug;248(2):438-46

Authors: Takakuwa KM, Halpern EJ

PURPOSE: To determine whether coronary computed tomographic (CT) angiography "triple rule-out" evaluation of emergency department (ED) patients presenting with symptoms suggestive of acute coronary syndrome (ACS) can help identify a subset of patients who can be discharged without adverse clinical outcomes within 30 days. MATERIALS AND METHODS: This protocol was approved by the university institutional review board. Each patient provided written informed consent prior to inclusion. Coronary CT angiography was performed in 201 consecutive low-to-moderate risk ACS patients. A triple rule-out protocol was used to evaluate for coronary disease, pulmonary embolism, aortic dissection, and other thoracic disease. Four patients were excluded because of technical problems. The remaining subjects underwent a 30-day follow-up. RESULTS: A disease process other than coronary atherosclerosis that explained the presenting symptoms was diagnosed in 22 (11%) of 197 patients. Clinically important noncoronary diagnoses that did not explain patient symptoms were identified in 27 (14%) of 197 additional patients. With respect to coronary artery disease, 10 patients had severe disease (>70% stenosis), 12 had moderate disease (50%-70% stenosis), 46 had mild disease (up to 50% stenosis), and 129 had no disease. No further diagnostic testing was performed in 133 (76%) of 175 of patients with no to mild coronary disease. At 30-day follow-up, the negative predictive value of coronary CT angiography with no more than mild disease was 99.4%. There were no adverse outcomes at 30 days. CONCLUSION: Triple rule-out coronary CT angiography evaluation of low-to-moderate risk ACS patients presenting to the ED provided a noncoronary diagnosis that explained the presenting complaint in 11% of patients, suggested the presence of significant moderate-to-severe coronary disease in 11% (22 of 197) of patients, and precluded additional diagnostic cardiac testing in the majority of patients with no adverse outcomes at 30-day follow-up.

PMID: 18641247 [PubMed - indexed for MEDLINE]

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MR Imaging of hepatocellular carcinoma in the cirrhotic liver: challenges and controversies.

Radiology. 2008 May;247(2):311-30

Authors: Willatt JM, Hussain HK, Adusumilli S, Marrero JA

The incidence of hepatocellular carcinoma (HCC) is expected to increase in the next 2 decades, largely due to hepatitis C infection and secondary cirrhosis. HCC is being detected at an earlier stage owing to the implementation of screening programs. Biopsy is no longer required prior to treatment, and diagnosis of HCC is heavily dependent on imaging characteristics. The most recent recommendations by the American Association for the Study of Liver Diseases (AASLD) state that a diagnosis of HCC can be made if a mass larger than 2 cm shows typical features of HCC (hypervascularity in the arterial phase and washout in the venous phase) at contrast material-enhanced computed tomography or magnetic resonance (MR) imaging or if a mass measuring 1-2 cm shows these features at both modalities. There is an ever-increasing demand on radiologists to detect smaller tumors, when curative therapies are most effective. However, the major difficulty in imaging cirrhosis is the characterization of hypervascular nodules smaller than 2 cm, which often have nonspecific imaging characteristics. The authors present a review of the MR imaging and pathologic features of regenerative nodules and dysplastic nodules and focus on HCC in the cirrhotic liver, with particular reference to small tumors and lesions that may mimic HCC. The authors also review the sensitivity of MR imaging for the detection of these tumors and discuss the staging of HCC and the treatment options in the context of the guidelines of the AASLD and the imaging criteria required by the United Network for Organ Sharing for transplantation. MR findings following ablation and chemoembolization are also reviewed.

PMID: 18430871 [PubMed - indexed for MEDLINE]

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