CT Scans Obtained for Nonpulmonary Indications: Associated Respiratory Findings of COVID-19

Background Atypical manifestations of coronavirus disease 2019 (COVID-19) are being encountered as the pandemic unfolds, leading to non-chest CT scans that may uncover unsuspected pulmonary disease. Purpose To investigate patients with primary nonrespiratory symptoms who underwent CT of the abdomen or pelvis or CT of the cervical spine or neck with unsuspected findings highly suspicious for pulmonary COVID-19. Materials and Methods This retrospective study from March 10, 2020, to April 6, 2020, involved three institutions, two in a region considered a hot spot (area of high prevalence) for COVID-19. Patients without known COVID-19 were included who presented to the emergency department (ED) with primary nonrespiratory (gastrointestinal or neurologic) symptoms, had lung parenchymal findings suspicious for COVID-19 at non-chest CT but not concurrent chest CT, and underwent COVID-19 testing in the ED. Group 1 patients had reverse transcription polymerase chain reaction (RT-PCR) results obtained before CT scan reading (COVID-19 suspected on presentation); group 2 had RT-PCR results obtained after CT scans were read (COVID-19 not suspected). Presentation and imaging findings were compared, and outcomes were evaluated. Descriptive statistics and Fisher exact tests were used for analysis. Results Group 1 comprised 62 patients (31 men, 31 women; mean age, 67 years ±17 [standard deviation]), and group 2 comprised 57 patients (28 men, 29 women; mean age, 63 years ± 16). Cough and fever were more common in group 1 (37 of 62 [60%] and 29 of 62 [47%], respectively) than in group 2 (nine of 57 [16%] and 12 of 57 [21%], respectively), with no significant difference in the remaining symptoms. There were 101 CT scans of the abdomen or pelvis and 18 CT scans of the cervical spine or neck. In group 1, non-chest CT findings provided the initial evidence of COVID-19-related pneumonia in 32 of 62 (52%) patients. In group 2, the evidence was found in 44 of 57 (77%) patients. Overall, the most common CT findings were ground-glass opacity (114 of 119, 96%) and consolidation (47 of 119, 40%). Major interventions (vasopressor medication or intubation) were required for 29 of 119 (24%) patients, and 27 of 119 (23%) died. Patients who underwent CT of the cervical spine or neck had worse outcomes than those who underwent abdominal or pelvic CT (P = .01). Conclusion In a substantial percentage of patients with primary nonrespiratory symptoms who underwent non-chest CT, CT provided evidence of coronavirus disease 2019-related pneumonia. © RSNA, 2020.

Reducing risk in the emergency department: a 12-month prospective longitudinal study of radiographer preliminary image evaluations

INTRODUCTION

Innovations are necessary to accommodate the increasing demands on emergency departments whilst maintaining a high level of patient care and safety. Radiographer Preliminary Image Evaluation (PIE) is one such innovation. The purpose of this study was to determine the accuracy of radiographer PIE in clinical practice within an emergency department over 12 months.

METHODS

A total of 6290 radiographic examinations were reviewed from 15 January 2016 to 15 January 2017. The range of adult and paediatric examinations incorporated in the review included the appendicular and axial skeleton including the chest and abdomen. Each examination was compared to the radiologist's report this allowed calculated mean sensitivity and specificity values to indicate if the radiographer's PIE was of a true negative/positive or false negative/positive value. Cases of no PIE participation or series' marked as unsure for pathology by the radiographer were also recorded. This allowed mean sensitivity, specificity and diagnostic accuracy to be calculated.

RESULTS

The study reported a mean ± 95% confidence level (standard deviation) for sensitivity, specificity, accuracy, no participation and unsure of 71.1% ± 2.4% (6.1), 98.4% ± 0.04% (0.9), 92.0% ± 0.68% (1.9), 5.1% (1.6) and 3.6% (0.14) respectively.

CONCLUSIONS

This study has demonstrated that the participating radiographers provided a consistent PIE service while maintaining a reasonably high diagnostic accuracy. This form of image interpretation can complement an emergency referrer's diagnosis when a radiologist's report is unavailable at the time of patient treatment. PIE promotes a reliable enhancement of the radiographer's role with the multi-disciplinary team.

In comparison with other abdominal imaging modalities, which radiologists interpret abdominal MRI?

PURPOSE

To assess subspecialty mix and case volumes of general and abdominal subspecialty radiologists interpreting abdominal MRI.

METHODS

The 2016 CMS Physician/Supplier Procedure Summary Master File was used to obtain billed counts of radiologist-interpreted abdominal fluoroscopy, US, CT, and MRI examinations. The CMS Physician and Other Supplier Public Use File was used to assess the subspecialty mix and case volume of the radiologists interpreting those examinations.

RESULTS

The fraction of all abdominal imaging examinations interpreted by generalists and abdominal subspecialty radiologists was 70.7% and 16.5% for fluoroscopy; 68.7% and 21.0% for US; 71.4% and 19.2% for CT; and 41.9% and 52.5% for MRI. In 2016, the fraction of general and abdominal radiologists interpreting > 50 fluoroscopy examinations on Medicare fee-for-service beneficiaries was 15.1% and 16.2%. For > 50 US examinations, the fraction was 61.5% and 60.5%; for > 50 CT examinations, 91.2% and 79.6%; and for > 50 MRI examinations, 4.0% and 28.5%. The fraction of abdominal imaging examinations interpreted overall by low-volume providers (those interpreting ≤ 50 examinations in 2016) was 59.5% for fluoroscopy, 17.5% for US, 6.3% for CT, and 50.6% for MRI.

CONCLUSION

Nationally, most abdominal fluoroscopy, US, and CT examinations are interpreted by general radiologists, who have similar annual volumes of these examinations as abdominal subspecialty radiologists. In contrast, most abdominal MRI examinations are interpreted by abdominal subspecialty radiologists, who attain considerably higher volumes. These findings have implications for workforce planning and abdominal imaging fellowship design to ensure their graduates are optimally prepared to contribute to their future practices.

Sex Hormone-Binding Globulin Levels in Young Men Are Associated With Nonalcoholic Fatty Liver Disease in Midlife

INTRODUCTION

Cross-sectional data note lower levels of testosterone and sex hormone-binding globulin (SHBG) levels in men with nonalcoholic fatty liver disease (NAFLD). Whether sex hormone levels in young men are predictive of later risk of NAFLD is not known.

METHODS

Among men in the prospective population-based multicenter Coronary Artery Risk Development in Young Adults study (mean age 50; n = 837), we assessed whether testosterone and SHBG levels measured at study year 10 (median age 35 years) were associated with prevalent NAFLD at study year 25. NAFLD was defined using noncontrast abdominal computed tomography (CT) scan after excluding other causes of hepatic steatosis. The association of testosterone and SHBG with prevalent NAFLD was assessed by logistic regression.

RESULTS

Total testosterone levels in young men were inversely associated with subsequent prevalent NAFLD on unadjusted analysis (odds ratio [OR] 0.64, 95% confidence interval 0.53-0.7, P < 0.001), although no longer significant after adjustment for year 10 metabolic covariates as well as change in metabolic covariates from years 10 to 25 (OR 0.99, 95% confidence interval 0.76-1.27). In contrast, there was a significant inverse association of SHBG with prevalent NAFLD, independent of testosterone and metabolic covariates (OR 0.68, OR 0.51-0.92, P = 0.013). On formal mediation testing, visceral adiposity was found to explain ∼41.0% (95% confidence interval 27%-73%) of the association of lower SHBG with prevalent NAFLD.

CONCLUSIONS

Lower levels of SHBG in young men are associated with increase in prevalent NAFLD in middle age, independent of comprehensive metabolic risk factors. SHBG may provide a novel marker of NAFLD risk in young men.

[Consistency analysis between preoperative CT enterography and intraoperative findings in patients undergoing surgery for Crohn's disease]

OBJECTIVE

To evaluate the diagnostic value of preoperative CT enterography (CTE) on obstruction, fistula and abscess formation compared to intraoperative findings in patients undergoing surgery for Crohn's disease(CD), aiming to provide reference to clinical practice.

METHODS

Preoperative CTE data of 176 CD patients confirmed by clinic, endoscopy, imaging, operation and pathology at the Department of General Surgery in Nanjing Jinling Hospital from January 2013 to December 2015 were enrolled in retrospective cohort study. All the patients underwent enhanced full abdominal CT scan using SIMENS SOMATOM Definition Flash 64 row dual-source CT machine. CTE scans were performed from the dome of diaphragm to the symphysis pubis. The CT images in arterial and venous phase were reconstructed with 1.0 mm thin layer, and then processed in MMWP 4.0 workstation including multi-planar recombination, surface recombination and maximum density projection. The sensitivity, specificity, positive and negative predictive value, false negative rate and accuracy of preoperative CTE on obstruction, fistula and abscess were compared with intraoperative findings.

RESULTS

Among 176 patients, 122 were males and 54 were females with median age of 29 (18 to 65) years, median disease duration of 48 (1 to 240) months, median time interval from CT scan to operation of 16(1 to 30) days, and median body mass index of 17.8 (10.8 to 34.7) kg/m². Twenty-six cases (14.8%) had nutritional risk (NRS2002≥3); 23 cases (13.1%) had lesions limited to ileum; 19 cases (10.8%) had lesions limited to colon; 126 cases (71.6%) had simultaneous lesions of ileum and colon, and 8 cases (4.5%) had lesion in upper gastrointestinal tract. A total of 199 lesions of small intestine were identified by preoperative CTE, including 131 of obstruction (65.8%), 42 of fistula (21.1%), and 26 of abscess (13.1%), while 235 lesions were confirmed by operation, including 133 of obstruction (56.6%), 74 of fistula (31.5%), 28 of abscess (11.9%). The modification of planned surgical procedure due to unexpected intraoperative findings were found in 29(16.5%) patients. The sensitivity, specificity, positive predictive value and negative predictive value of preoperative CTE were 86.4%, 78.8%, 86.9% and 76.0% for obstruction; 83.8%, 79.1%, 67.5% and 90.4% for fistula; and 96.2%, 98.0%, 90.1% and 99.3 for abscess, respectively.

CONCLUSION

Preoperative CTE can effectively evaluate the lesions of intestinal obstruction, fistula and abscess in CD patients, with the highest accuracy of abscess, and has quite good consistency with intraoperative findings, which may be used as the first choice of imaging diagnosis of CD.

Evaluation of extrapancreatic inflammation on abdominal computed tomography as an early predictor of organ failure in acute pancreatitis as defined by the revised Atlanta classification

The aim of the study was to determine whether extrapancreatic inflammation on computed tomography (EPIC) is helpful in predicting organ failure in the early phase of acute pancreatitis (AP) as defined by the 2012 revised Atlanta classification.Patients (n = 208) who underwent abdominal computed tomography (CT) within 24 hours after AP onset and admission were retrospectively identified. Each patient's EPIC score, Balthazar score, bedside index of severity in acute pancreatitis (BISAP), and systemic inflammatory response syndrome (SIRS) score were obtained. Primary endpoints were organ failure occurrence and death. Scores were evaluated by receiver operator characteristic (ROC) curve and area under the curve (AUC) analysis.Median age was 45 years (range: 18-83 years). Forty-seven patients (22.6%) developed organ failure, and 5 patients (2.4%) developed infection and underwent surgery. Two patients died. The median EPIC score was 2 (range: 0-7). EPIC score accuracy (AUC = 0.724) in predicting organ failure was similar to that of BISAP (0.773) and SIRS (0.801) scores, whereas Balthazar scoring was not significant (P = .293). An EPIC score of 3 or greater had a sensitivity and specificity of 80.65% and 63.16%, respectively. EPIC scores correlated moderately with organ failure severity (Spearman r = 0.321) and number of failed organs (r = 0.343).The EPIC scoring system can be useful in predicting the occurrence of organ failure, but it does not differentiate severity and number of failed organs in early phase AP.

Effectiveness of a radiation reduction campaign targeting children with gastrointestinal symptoms in a pediatric emergency department

Children feature more active cellular division and a smaller body area, which leads to a greater radiation dosage accumulation. We tried to reduce radiation hazards by reducing unnecessary radiological studies in a pediatric emergency department (PED) through the radiation reduction campaign.Our campaign involved a reduction from 2 (erect and supine) to 1 ordered abdominal plain radiograph (erect). This quasi-experimental, uncontrolled before-and-after study aimed to evaluate the campaign effect. We compared simple radiograph orders, length of stay (LOS) in PED, and return visit (RV) to PED between the before period (June 1, 2011-May 30, 2014) and the after period (June 1, 2014-May 30, 2015). Piecewise regression was used to assess rate differences between the periods.A total of 10,729 and 3515 patients were included before and after the campaign, respectively. During study periods, 9647 (90%) and 2710 (77%) total abdominal radiographs were ordered, respectively (rate difference = 13%; P < 0.001), and the slopes of rate changes were 0.03 and -0.71, respectively (P = 0.056). The total abdominal erect and supine film rate slope decreased from -0.19 to -2.86 (P = 0.004). The RV rate did not change (220 [2%] vs 56 [2%], respectively; P = 0.104). The slope of total RV rate changed from -0.01 to -0.05 (P = 0.132), and the slope of LOS changed from 0.001 to -0.352 (P = 0.243).The campaign to reduce abdominal radiograph orders in pediatric patients successfully reduced the abdominal plain film X-ray rate without on the RV rate and the LOS.

Spatial anatomy of the round ligament, gallbladder, and intrahepatic vessels in patients with right-sided round ligament of the liver

PURPOSE

To analyze the vascular structure of the liver in patients with a right-sided round ligament.

METHODS

We reviewed 16 patients with a right-sided round ligament and 3 polysplenia and situs inversus patients with a left-sided round ligament who underwent multidetector row CT with contrast media. The patient population consisted of 13 men and 6 women (mean 62 years). We analyzed the axial and volume-rendered images for the location of the round ligament, gallbladder, portal veins, hepatic veins, and hepatic artery. The following imaging findings for the patients with polysplenia and situs inversus were horizontally reversed.

RESULTS

The prevalence of a right-sided round ligament with and without polysplenia was 75 and 0.11 %, respectively. The gallbladder was located to the right, below, and left of the round ligament in 27.7, 38.8 and 33.3 %, respectively. Independent branching of the right posterior portal vein was noted in 57.8 %. PV4 was difficult to identify in 36.8 %. The middle hepatic vein was located to the left of the round ligament. Two branching patterns for the lateral and medial branches of the right anterior hepatic artery were noted: the common (44.4 %) and separated types (55.5 %). Both of the right anterior hepatic artery and portal vein ramified into two segments; the lateral segment with many branches and the medial segment with a few branches.

CONCLUSIONS

The right-sided round ligament divided the right anterior section into the lateral and medial segments based on the portal vein and hepatic artery anatomy.

Utility of Reviewing Radiology Studies in Electronic Medical Records When Preparing Bone Mineral Density Reports

We quantitated how often review of recent radiology studies provides information useful to the densitometrist. While preparing bone mineral density (BMD) reports on 1012 consecutive patients, radiology reports in electronic medical records (EMRs) for the previous 5 years at potentially relevant sites (lumbar spine X-rays, abdominal computed tomography (CT) scans, and so forth) were reviewed. When a study was found, it received a grade according to how relevant findings were to the BMD report: "1" for studies that were irrelevant, "2" for those that confirmed the impression formed from review of the BMD images, "3" for those that clarified the impression that was unclear after reviewing the BMD images, and "4" for those that revealed new relevant data when no abnormality was noted on review of the BMD images. A total of 562 patients (55.5%) had a radiologic study at a site of potential interest within the past 5 years. Fifty-three patients (5.2% of all patients) had a grade 4 study, 88 patients (8.7% of all patients) had a grade 3 study, and 185 patients (18.3% of all patients) had a grade 2 study. Two hundred sixty-four patients (25.8%) had a grade 2 or 3 study, and 299 (29.5%) had a grade 2-4 study. The radiographic study that was most likely to be found in patients' EMR was chest X-ray (34.7% of all patients), but it was also the one that was least likely to have any relevance to the reader; only 10.5% of the total chest X-rays were graded 2-4. The next most likely studies to be found in patients' EMR were abdominal CT scans (18.0% of all patients) and lumbar spine X-rays (14.4% of all patients), but these studies were much more likely to be useful to the reader, as 62.6% of abdominal CT scans and 78.1% of lumbar spine X-rays were graded 2-4. The likelihood of a patient having radiologic examinations in the EMR at sites potentially relevant to the BMD reader is high, but the likelihood that these clarify abnormalities noted on BMD is only moderate. Review of the EMR is unlikely to be relevant when the dual-energy X-ray absorptiometry images are normal.

Predicting High Imaging Utilization Based on Initial Radiology Reports: A Feasibility Study of Machine Learning

RATIONALE AND OBJECTIVES

Imaging utilization has significantly increased over the last two decades, and is only recently showing signs of moderating. To help healthcare providers identify patients at risk for high imaging utilization, we developed a prediction model to recognize high imaging utilizers based on their initial imaging reports.

MATERIALS AND METHODS

The prediction model uses a machine learning text classification framework. In this study, we used radiology reports from 18,384 patients with at least one abdomen computed tomography study in their imaging record at Stanford Health Care as the training set. We modeled the radiology reports in a vector space and trained a support vector machine classifier for this prediction task. We evaluated our model on a separate test set of 4791 patients. In addition to high prediction accuracy, in our method, we aimed at achieving high specificity to identify patients at high risk for high imaging utilization.

RESULTS

Our results (accuracy: 94.0%, sensitivity: 74.4%, specificity: 97.9%, positive predictive value: 87.3%, negative predictive value: 95.1%) show that a prediction model can enable healthcare providers to identify in advance patients who are likely to be high utilizers of imaging services.

CONCLUSIONS

Machine learning classifiers developed from narrative radiology reports are feasible methods to predict imaging utilization. Such systems can be used to identify high utilizers, inform future image ordering behavior, and encourage judicious use of imaging.

Written Informed Consent for Computed Tomography of the Abdomen/Pelvis is Associated with Decreased CT Utilization in Low-Risk Emergency Department Patients

INTRODUCTION

The increasing rate of patient exposure to radiation from computerized tomography (CT) raises questions about appropriateness of utilization. There is no current standard to employ informed consent for CT (ICCT). Our study assessed the relationship between informed consent and CT utilization in emergency department (ED) patients.

METHODS

An observational multiphase before-after cohort study was completed from 4/2010-5/2011. We assessed CT utilization before and after (Time I/Time II) the implementation of an informed consent protocol. Adult patients were included if they presented with symptoms of abdominal/pelvic pathology or completed ED CT. We excluded patients with pregnancy, trauma, or altered mental status. Data on history, exam, diagnostics, and disposition were collected via standard abstraction tool. We generated a multivariate logistic model via stepwise regression, to assess CT utilization across risk groups. Logistic models, stratified by risk, were generated to include study phase and a propensity score that controlled for potential confounders of CT utilization.

RESULTS

7,684 patients met inclusion criteria. In PHASE 2, there was a 24% (95% CI [10-36%]) reduction in CT utilization in the low-risk patient group (p<0.002). ICCT did not affect CT utilization in the high-risk group (p=0.16). In low-risk patients, the propensity score was significant (p<0.001). There were no adverse events reported during the study period.

CONCLUSION

The implementation of ICCT was associated with reduced CT utilization in low-risk ED patients. ICCT has the potential to increase informed, shared decision making with patients, as well as to reduce the risks and cost associated with CT.

Patient-specific dose calculations for pediatric CT of the chest, abdomen and pelvis

BACKGROUND

Organ dose is essential for accurate estimates of patient dose from CT.

OBJECTIVE

To determine organ doses from a broad range of pediatric patients undergoing diagnostic chest-abdomen-pelvis CT and investigate how these relate to patient size.

MATERIALS AND METHODS

We used a previously validated Monte Carlo simulation model of a Philips Brilliance 64 multi-detector CT scanner (Philips Healthcare, Best, The Netherlands) to calculate organ doses for 40 pediatric patients (M:F = 21:19; range 0.6-17 years). Organ volumes and positions were determined from the images using standard segmentation techniques. Non-linear regression was performed to determine the relationship between volume CT dose index (CTDIvol)-normalized organ doses and abdominopelvic diameter. We then compared results with values obtained from independent studies.

RESULTS

We found that CTDIvol-normalized organ dose correlated strongly with exponentially decreasing abdominopelvic diameter (R(2) > 0.8 for most organs). A similar relationship was determined for effective dose when normalized by dose-length product (R(2) = 0.95). Our results agreed with previous studies within 12% using similar scan parameters (e.g., bowtie filter size, beam collimation); however results varied up to 25% when compared to studies using different bowtie filters.

CONCLUSION

Our study determined that organ doses can be estimated from measurements of patient size, namely body diameter, and CTDIvol prior to CT examination. This information provides an improved method for patient dose estimation.

Identification of Incidental Pulmonary Nodules in Free-text Radiology Reports: An Initial Investigation

Advances in image quality produced by computed tomography (CT) and the growth in the number of image studies currently performed has made the management of incidental pulmonary nodules (IPNs) a challenging task. This research aims to identify IPNs in radiology reports of chest and abdominal CT by Natural Language Processing techiniques to recognize IPN in sentences of radiology reports. Our preliminary analysis indicates vastly different pulmonary incidental findings rates for two different patient groups.

Follow-up Recommendation Detection on Radiology Reports with Incidental Pulmonary Nodules

The management of follow-up recommendations is fundamental for the appropriate care of patients with incidental pulmonary findings. The lack of communication of these important findings can result in important actionable information being lost in healthcare provider electronic documents. This study aims to analyze follow-up recommendations in radiology reports containing pulmonary incidental findings by using Natural Language Processing and Regular Expressions. Our evaluation highlights the different follow-up recommendation rates for oncology and non-oncology patient cohorts. The results reveal the need for a context-sensitive approach to tracking different patient cohorts in an enterprise-wide assessment.

Segmentation of abdominal organs from CT using a multi-level, hierarchical neural network strategy

Precise measurements on abdominal organs are vital prior to the important clinical procedures. Such measurements require accurate segmentation of these organs, which is a very challenging task due to countless anatomical variations and technical difficulties. Although, several features with various classifiers have been designed to overcome these challenges, abdominal organ segmentation via classification is still an emerging field in order to reach desired precision. Recent studies on multiple feature-classifier combinations show that hierarchical systems outperform composite feature-single classifier models. In this study, how hierarchical formations can translate to improved accuracy, when large size feature spaces are involved, is explored for the problem of abdominal organ segmentation. As a result, a semi-automatic, slice-by-slice segmentation method is developed using a novel multi-level and hierarchical neural network (MHNN). MHNN is designed to collect complementary information about organs at each level of the hierarchy via different feature-classifier combinations. Moreover, each level of MHNN receives residual data from the previous level. The residual data is constructed to preserve zero false positive error until the last level of the hierarchy, where only most challenging samples remain. The algorithm mimics analysis behaviour of a radiologist by using the slice-by-slice iteration, which is supported with adjacent slice similarity features. This enables adaptive determination of system parameters and turns into the advantage of online training, which is done in parallel to the segmentation process. Proposed design can perform robust and accurate segmentation of abdominal organs as validated by using diverse data sets with various challenges.

Plain abdominal radiographs in patients with Crohn's disease: radiological findings and diagnostic value

AIM

To determine the diagnostic yield and clinical value of plain film of the abdomen (PFA) in Crohn's disease (CD) patients and to determine whether performance of PFA yields definitive diagnostic information or whether additional imaging examinations are required.

MATERIALS AND METHODS

One hundred and seventy-seven CD patients underwent 643 PFAs during the period September 1992 to August 2008. Two radiologists blinded to the clinical details independently evaluated individual PFAs and/or their reports for abnormal findings using the following criteria: normal, small bowel (SB) findings; colonic findings, acute CD complications, extra-colonic findings; global assessment/impression. The results of additional imaging studies performed within 5 days of PFA were recorded and findings were analysed.

RESULTS

A mean of 3.6 (range 1-22) PFAs was performed per patient during the study period. Almost 70% of films were normal (n = 449). SB abnormalities were detected in 21.8% (n = 140) PFAs; most commonly dilated loops (18.8%, n = 121) and mucosal oedema (5%, n = 32). Colonic abnormalities were present in 11.4% (n = 73); most commonly mucosal oedema (7.5%, n = 48) and dilated loops (5%, n = 32). Four cases of pneumoperitoneum were detected. There was no case of toxic megacolon. There was one case in which intra-abdominal abscess/collection was suspected and two cases of obstruction/ileus. Extracolonic findings (renal calculi, sacro-iliitis, etc.) were identified in 7.5% (n = 48). PFAs were followed by additional abdominal imaging within 5 days of PFA in 273/643 (42.5%) of cases.

CONCLUSION

Despite the high rates of utilization of PFA in CD patients, there is a low incidence of abnormal findings (32.5%). Many of the findings are non-specific and clinically irrelevant and PFA is frequently followed by additional abdominal imaging examinations.

Is it worth looking? Abdominal imaging after pancreatic cancer resection: a national study

INTRODUCTION

Abdominal imaging is often performed after pancreatic cancer resection. We attempted to quantify the volume and estimate the cost of complex imaging after pancreatectomy nationwide, and to determine whether their frequent use confers benefit.

METHODS

Patients with pancreatic adenocarcinoma who underwent resection were identified in Surveillance, Epidemiology and End Results-Medicare (1991-2005). Claims for abdominal imaging ≤5 years after resection were analyzed. Patients receiving annual CT scans were identified. Univariate and multivariate analyses were performed. To assess frequency of annual CT scanning in patients with superior survival, the top decile was further analyzed.

RESULTS

Eleven thousand eight hundred fifty studies were performed on 2,217 patients. Ten thousand five hundred forty-two (89%) were CT scans. The median number of scans doubled from three in 1991 to six in 2005 (p < 0.0001). Among patients with sufficient survival to allow for analysis, 51.3% received annual CT scans, while only 32.4% of top-performing patients received annual scans. Univariate analysis of the 10% of patients with superior survival did not reveal any significant benefit associated with annual imaging.

CONCLUSION

Utilization of complex imaging after pancreatic cancer resection has increased substantially among Medicare beneficiaries, driven primarily by an increasing number of CT scans. Our study demonstrated no significant survival benefit among patients who received scans on a routine basis.

Commentary: for the children's sake, avoid non-contrast CT

Enough literature now exists such that doing a non-contrast abdominal or chest computed tomography (CT) scan for suspected mass lesions in children borders on malpractice. Although there is great uncertainty regarding estimated radiation doses and long-term cancer risks in childhood, there is no doubt that an entirely unnecessary CT study does more harm than good. When a chest or abdominal mass is suspected in a child, only a post-intravenous contrast enhanced CT examination is needed, and a prior non-enhanced CT run exposes the child to unnecessary radiation.

Increased neck soft tissue mass and worsening of obstructive sleep apnea after growth hormone treatment in men with abdominal obesity

BACKGROUND

Risk factors for obstructive sleep apnea (OSA) are male gender, obesity and abnormalities in neck soft tissue mass. OSA is associated with both growth hormone (GH) excess and severe GH deficiency in adults. Adults with abdominal obesity have markedly suppressed GH secretion.

AIM

To study the effect of GH treatment on OSA in abdominally obese men with impaired glucose tolerance.

PATIENTS AND METHODS

Forty men with abdominal obesity and glucose intolerance were randomized in a prospective, 12-month double-blind trial to receive either GH or placebo. The treatment groups had similar BMI and waist circumference. Overnight polysomnography and computed tomography to assess muscle and fat distribution in the neck and abdomen were performed at baseline and after 12 months.

RESULTS

GH treatment increased insulin-like growth-factor-1i from (mean [SD]) 168 (72) to 292 (117) microg/L, the apnea-hypopnea index from (n/h) 31 (20) to 43 (25) and oxygen-desaturation index from (n/h) 18 (14) to 29 (21) (p = 0.0001, 0.001, 0.002). Neck transverse diameter, circumference and total cross-sectional area (p = 0.007, 0.01, 0.02) increased, while abdominal visceral adipose tissue (p = 0.007) was reduced. No between-group differences in total sleep time, REM sleep, NREM sleep, and time spent in supine position were found. The Epworth sleepiness scale score was unchanged.

CONCLUSIONS

GH treatment increased the severity of OSA in abdominally obese men. The possible mechanism appears to be reflected by the GH-induced increase of measures of neck volume. The present results, to some extent, argue against that low GH/IGF-I activity is a primary cause of OSA in abdominally obese men.

The in vivo relationship between cross-sectional area and CT dose index in abdominal multidetector CT with automatic exposure control

The relationship between patient cross-sectional area and both volume CT dose index (CTDI) and dose length product was explored for abdominal CT in vivo, using a 16 multidetector row CT (MDCT) scanner with automatic exposure control. During a year-long retrospective survey of patients with MDCT for symptoms of abdominal sepsis, cross-sectional areas were estimated using customised ellipses at the level of the middle of vertebra L3. The relationship between cross-sectional area and the exposure parameters was explored. Scans were performed using a LightSpeed 16 (GE Healthcare Medical Systems, Milwaukee, WI) operated with tube current modulation. From a survey of 94 patients it was found that the CTDI increased with the increase in patient cross-sectional area. The relationship was logarithmic rather than linear, with a least-squares fit to the data (R(2) = 0.80). For abdominal CT the cross-sectional area gave a measure of patient size based on the region of the body to be exposed. Exposure parameters increased with increasing cross-sectional area and the greater radiation exposure of larger patients was partly a consequence of their size. Given increasing obesity levels we believe that cross-sectional area and scan length should be added to future dose surveys, allowing patient size to be considered as a factor of relevance when examining population doses.

Nationwide surveys of chest, abdomen, lumbosacral spine radiography, and upper gastrointestinal fluoroscopy: a summary of findings

This paper reports findings from Nationwide Evaluation of X-ray Trends surveys conducted in 2001, 2002, and 2003 of clinical facilities that perform routine radiographic examinations of the adult chest, abdomen, lumbosacral spine, and upper gastrointestinal fluoroscopic examinations. Randomly identified clinical facilities were surveyed in approximately 40 participating states. For the surveyed radiographic exams, additional facilities that use computed radiography or digital radiography were surveyed to ensure adequate sample sizes for determining comparative statistics. State radiation control personnel performed site visits and collected data on patient exposure, radiographic/fluoroscopic technique factors, image quality, and quality-control and quality-assurance practices. Results of the NEXT surveys are compared with those of previous surveys conducted in 1964 and 1970 by the U.S. Public Health Service and the Food and Drug Administration. An estimated 155 million routine adult chest exams were performed in 2001. Average patient entrance skin air kerma from chest radiography at facilities using digital-based imaging modalities was found to be significantly higher (p < 0.001), but not so for routine abdomen or lumbosacral spine radiography. Digital-based imaging showed a substantial reduction in patient exposure for the radiographic portion of the routine upper gastrointestinal fluoroscopy exam. Long-term trends in surveyed diagnostic examinations show that average patient exposures are at their lowest levels. Of concern is the observation that a substantial fraction of surveyed non-hospital sites indicated they do not regularly have a medical physics survey conducted on their radiographic equipment. These facilities are likely unaware of the radiation doses they administer to their patients.

Exposure of extremely low birth weight infants to diagnostic X-Rays: a longitudinal study

AIM

To quantify the number of chest and abdominal radiograms performed in surviving singleton extremely low birth weight (ELBW) infants in order to examine whether changes in imaging application occurred during the last 21 years (1987-2007).

METHODS

Clinical and radiological data of 225 out of 229 surviving infants were obtained and associations with time and clinical variables were evaluated.

RESULTS

The number of chest X-Rays performed per infant was 10.3 +/- 11.1 (mean +/- SD), median = 7; range = 0-77 and the number of abdominal radiograms was 5.6 +/- 7.1, median = 3; range = 0-61. The number of chest and abdominal X-Rays performed per patient during 1987-1996 was very similar to that of 1997-2007, and no appreciable change of trend was observed along the years. There were negative and statistically significant correlations between the gestational age and the number of radiograms performed per patient (chest X-Rays: r =-0.402; p < 0.001, abdominal X-Rays: r =-0.182; p = 0.006). Controlling for gestational age, reduced numbers of radiograms per patient (abdominal: b =-1.20, p = 0.235; chest: b =-3.08, p = 0.035) were demonstrated in the second period. Patients with complicated clinical course were exposed to significantly more radiograms.

CONCLUSION

Controlling for gestational age, a reduced number of exposures to chest radiograms was demonstrated during 1997-2007 compared with 1987-1996. Measures to reduce radiation, especially in complicated cases, are advocated.

Entrance surface dose and image quality: comparison of adult chest and abdominal X-ray examinations in general practitioner clinics, public and private hospitals in Malaysia

This study was undertaken to compare the entrance surface dose (ESD) and image quality of adult chest and abdominal X-ray examinations conducted at general practitioner (GP) clinics, and public and private hospitals in Malaysia. The surveyed facilities were randomly selected within a given category (28 GP clinics, 20 public hospitals and 15 private hospitals). Only departmental X-ray units were involved in the survey. Chest examinations were done at all facilities, while only hospitals performed abdominal examinations. This study used the x-ray attenuation phantoms and protocols developed for the Nationwide Evaluation of X-ray Trends (NEXT) survey program in the United States. The ESD was calculated from measurements of exposure and clinical geometry. An image quality test tool was used to evaluate the low-contrast detectability and high-contrast detail performance under typical clinical conditions. The median ESD value for the adult chest X-ray examination was the highest (0.25 mGy) at GP clinics, followed by private hospitals (0.22 mGy) and public hospitals (0.17 mGy). The median ESD for the adult abdominal X-ray examination at public hospitals (3.35 mGy) was higher than that for private hospitals (2.81 mGy). Results of image quality assessment for the chest X-ray examination show that all facility types have a similar median spatial resolution and low-contrast detectability. For the abdominal X-ray examination, public hospitals have a similar median spatial resolution but larger low-contrast detectability compared with private hospitals. The results of this survey clearly show that there is room for further improvement in performing chest and abdominal X-ray examinations in Malaysia.

Radiation doses from some common paediatric X-ray examinations in Sudan

Radiation doses to patients from some common paediatric X-ray examinations were studied in three hospitals in Khartoum state, Sudan. Entrance surface dose (ESD) was determined from exposure settings using DosCal software. Totally, 459 patients were included in this study. Mean ESDs obtained from anteroposterior projection for chest, skull, abdomen and pelvis for neonates falls in the range of 52-100, 115-169, 145-183, 204-242 microGy, respectively. For a 1-y-old infant, mean ESD range was 80-114, 153-202, 204-209, 181-264 microGy, respectively. Some doses for neonates and infants were exceeding the reference doses by >20%. The results highlighted that a good technique has to adhere to guidelines necessarily. As demonstrated elsewhere, patients' doses were high in departments using single-phase generators compared with those using constant potential. The results presented will serve as a baseline data needed for deriving reference doses for paediatric X-ray examinations in Sudan.

Multi-detector computed tomography in critically ill patients

BACKGROUND

There is a lack of studies showing the overall impact of multi-detector computed tomography (MDCT) on the treatment of critically ill patients in a general intensive care unit (ICU) setting.

METHODS

A prospective observational study on the effects of MDCT on the treatment of patients in a 12-bed medical-surgical ICU in a university hospital providing tertiary care.

RESULTS

During the 9-month study period, there were 343 admissions with ICU length of stay longer than 48 h. Of these patients, 64 (19%) had had inconclusive findings with other modalities of radiological imaging, and they underwent altogether 82 MDCT examinations. Fifty examinations (61%) resulted in a change of treatment. The changes included 22 surgical interventions, 16 percutaneous or paranasal interventions, 15 changes of antimicrobial therapy, three withdrawals of active treatment, and four other changes of treatment. Eight patients underwent two and one patient underwent three changes of treatment. Twenty examinations (24%) were regarded as otherwise necessary for clinical decision-making, although no change in the treatment was indicated. Twelve examinations (15%) failed to provide any additional information relevant to the patient's treatment.

CONCLUSION

Sixty-one percent of the MDCT examinations led to a change of treatment, and 24% of them otherwise contributed to or supported clinical decision-making, suggesting that MDCT examination is helpful in the case of general ICU patients, with inconclusive findings with other imaging modalities.

Acute Abdominal Pain: Diagnostic Impact of Immediate CT Scanning

BACKGROUND

Acute abdominal pain is a common diagnostic problem. This study aimed to evaluate the routinely use of contrast enhanced computed tomographic (CT) scanning early in the diagnostic process.

METHODS

A retrospective review of 2,222 patients with acute abdominal pain who underwent contrast enhanced CT scanning within 24 h after admission. The diagnoses obtained were compared with the final diagnoses after 1 month.

RESULTS

After CT scanning the following diagnoses were suggested as the primary cause of the abdominal pain: nonspecific abdominal pain 984 (44.3%), appendicitis 354 (15.9%), bowel obstruction 190 (8.6%), diverticulitis 182 (8.2%), gastrointestinal perforation 52 (2.3%), gallstone disease 64 (2.9%), pancreatitis 72 (3.2%), inflammatory bowel disease 13 (0.6%), intra-abdominal malignancy 34 (1.5%), vascular disease (including 1 completely cured patient with paradoxical embolization in the superior mesenteric artery) 33 (1.5%), urological 131 (5.9%), gynecological 54 (2.4%), miscellaneous 31 (1.4%). In 28 cases a conclusive CT examination could not be carried out. The suggested diagnoses were correct in 2,151 cases (96.8%). In 16 cases (0.7%) an incorrect diagnosis was reported, leading to 7 unnecessary laparotomies. False negative reports were obtained in 27 cases (1.2%). After CT examination 500 patients could be discharged immediately.

CONCLUSIONS

Contrast-enhanced CT scanning results in superior diagnostic precision in patients with acute abdominal pain. The present work supports the strategy to include this examination early in the routine diagnostic process.

[Acute abdomen film: is there hope of changing referring patterns?]

An abdomen radiograph (KUB) is frequently requested by ER physicians as part of the inital work-up of patients. However, other imaging studies are now routinely available in the acute setting that may make the KUB an obsolete and unnecessary examination. The first part of this study was to assess the current referral patterns for urgent KUB in our center; the improper referral pattern for KUB in terms of requests for unnecessary exams 48,5% as well as number of technical errors in terms of inadequate radiographic projection for the suspected pathology 47% were recorded. In a second part, the impact of corrective actions at one month, 2 months and 6 months was assessed and we observed a decrease of about 20% of the number of KUB scheduled by the ER physician. Our results confirm that it is possible to teach ER physicians to more appropriately order imaging studies, which should improve patient care and generate savings. Long term correction of referral patterns is possible if all actors remain involved in this process.

Abdominal CT scanning in reproductive-age women with right lower quadrant abdominal pain: does its use reduce negative appendectomy rates and healthcare costs?

Although acute appendicitis is the most frequent cause of the acute abdomen in the United States, its accurate diagnosis in reproductive-age women remains difficult. Problems in making the diagnosis are evidenced by negative appendectomy rates in this group of 20 per cent to 45 per cent. Abdominal CT scanning has been used in diagnosing acute appendicitis, but its reliability and usefulness remains controversial. There is concern that the use of CT scanning to make this diagnosis leads to increased and unwarranted healthcare charges and costs. The purpose of our study is to determine if abdominal CT scanning is an effective test in making the diagnosis of acute appendicitis in reproductive-age women (age, 16-49 years) with right lower quadrant abdominal pain and to determine if its use is cost-effective. From January 2003 to December 2006, 439 patients were identified from our academic surgical database and confirmed by chart review as undergoing an appendectomy with a pre- or postoperative diagnosis of acute appendicitis. Data, including age, presence and results of preoperative abdominal CT scans, operative findings, and pathology reports were reviewed. Comparison of patients receiving a preoperative CT scan with those who did not was performed using chi-squared analysis. In the subgroup of reproductive-age women, there was a significant difference in negative appendectomy rates of 17 per cent in the group that received abdominal CT scans versus 42 per cent in the group that did not (P < 0.038). After accounting for the patient and insurance company costs, abdominal CT scan savings averaged $1412 per patient. Abdominal CT scanning is a reliable, useful, and cost-effective test for evaluating right lower quadrant abdominal pain and making the diagnosis of acute appendicitis in reproductive-age women.

Frequency of radiology self-referral in abdominal computed tomographic scans and the implied cost

Concerns over rising imaging costs have led to the consideration by Medicare to limit the ability of clinicians to bill for image interpretation. This move has often been justified as a method to limit self-referral. However, clinicians may not be the only ones capable of referring imaging business to themselves.

OBJECTIVE

This study was conducted to evaluate the frequency and potential cost of self-referral by radiologists found in dictated reports of abdominal computed tomographic (CT) scans for emergency patients.

METHODS

A retrospective chart review of all abdominal CTs performed at a level 1 academic urban emergency department (ED) with an annual census of 80,000 patients for a 12-month period was performed. Two investigators reviewed the medical record dictation on each abdominal CT performed on ED patients older than 18 years, for specific recommendations for additional radiologic testing. To check for agreement, both investigators reviewed approximately 20% of the charts. Recommended additional radiologic tests were recorded, and their costs were estimated by the lowest regional Medicare reimbursements for each test; professional and facilities fees were combined. Statistical methodology included descriptive statistics and interrater agreement.

RESULTS

A total of 785 reports of abdominal CTs were reviewed. Of these reports, 246 (31%) specifically recommended an additional imaging study be obtained for a specific finding. In 38 (5%) cases, 2 separate imaging studies were suggested. The total lowest cost for additional imaging among all of the patients studied was $58,157. The mean suggested charge per patient with additional imaging self-referral was $242.32. The additional suggested imaging averaged to $74.09 (95% confidence interval, 63.67-84.50) for each patient receiving an abdominal CT scan in the ED. The largest suggested cost was $1045. Extrapolation to a national level means that more than $226 million of additional costs are seen annually from such CTs. No attempt was made to evaluate the appropriateness of the suggested imaging.

CONCLUSIONS

A type of radiology self-referral is possible and can add considerable cost to patient care. In our study, an average of $74 of extra imaging was suggested for each patient who received an abdominal CT. If this holds up nationwide, Medicare can expect at least $226 million worth of radiology self-referrals per year on patients getting abdominal CT.

Accuracy of abdominal radiography in acute small-bowel obstruction: does reviewer experience matter?

OBJECTIVE

The purposes of this study were to determine the accuracy of abdominal radiography in the detection of acute small-bowel obstruction (SBO), to assess the role of reviewer experience, and to evaluate individual radiographic signs of SBO.

MATERIALS AND METHODS

A retrospective study was performed in which the subjects were 90 patients with suspected SBO who underwent CT and abdominal radiography within 48 hours of each other. The patients were enrolled from June 1, 2003, to February 2004. Twenty-nine of the patients had proven SBO. Hard-copy radiographs were reviewed by three groups of radiologists: senior staff, junior staff, and second-year radiology residents. Each reviewer evaluated the quality of the radiographs, patient position for acquisition of the radiographs, and whether SBO was present. The reviewers rated their confidence on a five-point scale and recorded the presence or absence of specific radiographic signs of SBO. Chi-square tests were used to compare the three groups. A statistically significant finding was considered p < 0.05. Receiver operating characteristic (ROC) curves were fit with a 10-point confidence scale.

RESULTS

The sensitivity for SBO among the six reviewers ranged from 59% to 93%. The senior staff members were significantly more accurate. The mean sensitivity, specificity, and accuracy for all six reviewers were 82%, 83%, and 83%, respectively. Three radiographic signs were highly significant (p < 0.001): two or more air-fluid levels, air-fluid levels wider than 2.5 cm, and air-fluid levels differing more than 5 mm from one another in the same loop of small bowel. ROC analysis showed that senior staff is significantly more accurate than the other groups in the detection of acute SBO.

CONCLUSION

Our results confirmed that abdominal radiographs are accurate in the detection of acute SBO, that more-experienced radiologists are more accurate than less-experienced reviewers in the evaluation of abdominal radiographs, and that three types of air-fluid levels are highly predictive of the presence of SBO.

Emergency department evaluation of ventricular shunt malfunction: is the shunt series really necessary?

OBJECTIVE

The malfunction of a ventricular shunt is one of the most common clinical problems encountered in pediatric neurosurgery. Standard emergency department (ED) evaluation of suspected shunt malfunction consists of plain radiographs of the skull, neck, chest, and abdomen (shunt series) to look for mechanical breaks, kinks, and disconnections in the shunt, and a cranial computed tomography (CT) scan to evaluate for signs of increased ventricular size. We hypothesized, however, that in the context of a cranial CT scan that did not demonstrate a shunt malfunction, obtaining the shunt series would not prove to be clinically useful.

METHODS

A retrospective chart review was conducted of all patients younger than 18 years with a history of a ventricular shunt who presented to an urban, tertiary pediatric ED between January 1, 2000, and September 30, 2004, for suspected shunt malfunction. Demographic and clinical characteristics of patients were recorded, as well as the results of shunt series and cranial CT scans. Shunt malfunction was defined as the performance of a shunt revision within 1 week of radiographic evaluation.

RESULTS

During the study period, 291 children with a ventricular shunt were evaluated in the ED 461 times for suspected shunt malfunction. The mean age of patients was 90.6 months (SD, 71.5 months); 163 (58.5%) were men, and 209 (71.8%) were white. Three hundred sixty patients (78.1%) had a shunt series performed during their ED evaluation, and 410 (88.9%) had a CT scan of the head. Seventy-one patients (15.4%) were diagnosed with shunt malfunction. Twenty-two had a normal cranial CT scan. Of these patients, 6 had an abnormal shunt series, and 14 had a normal shunt series.

CONCLUSIONS

The routine use of the shunt series seems warranted in the evaluation of the child with suspected shunt malfunction as children with shunt malfunction may present with a normal cranial CT scan but an abnormal shunt series.

Extrapancreatic inflammation on abdominal computed tomography as an early predictor of disease severity in acute pancreatitis: evaluation of a new scoring system

OBJECTIVE

To introduce a new scoring system based on signs of systemic inflammation on computed tomography (CT) [ExtraPancreatic Inflammation on CT (EPIC) score] and evaluate this score as an early prognostic tool.

METHODS

Forty patients with acute pancreatitis who received an abdominal CT within 24 h after admission were included in the study. The Balthazar score, the CT Severity Index, and the EPIC score (based on the presence of pleural effusion, ascites, and retroperitoneal fluid collections) were calculated for all patients. The end points were the occurrence of severe acute pancreatitis (local complication or presence of organ failure for more than 48 h) and in hospital mortality. This score was evaluated by calculating receiver operator characteristic (ROC) curves and the area under the ROC curve.

RESULTS

Mean age of the patients was 50 (+/-17.7) years, and Ranson score was 3.3. Fourteen (35%) patients developed severe disease; in hospital mortality was 15% (6/40). The mean EPIC score was 3.6 (+/-2.0). The area under the ROC curve for predicting severe disease and mortality was 0.91 (95% confidence interval, 0.83-0.99) and 0.85 (95% confidence interval, 0.71-0.99), respectively. An EPIC score of 4 or more had a 100% sensitivity and 70.8% specificity for predicting severe pancreatitis. The EPIC score was superior to the Balthazar score and CT Severity Index to predict outcome.

CONCLUSIONS

In patients with acute pancreatitis, extrapancreatic inflammation assessed by abdominal CT scan and quantified with the EPIC score allows accurate estimation of disease severity and mortality within 24 h of admission.

Survey of doses and frequency of X-ray examinations on children at the intensive care unit of a large reference pediatric hospital

OBJECTIVE

This work aims to evaluate the entrance surface dose (ESD), the body organ dose (BOD) and the effective dose (E) resulting from pediatric radiological procedures with the use of portable X-ray equipments.

MATERIALS AND METHODS

The software DoseCal was used to evaluate the doses imparted to patients. The children were classified according to their weight and age groups, and the study included three sectors of the intensive care unit of a large reference pediatric hospital in Rio de Janeiro.

RESULTS

A total of 518 radiographs have been performed, (424 for chest and 94 for abdomen). The statistical data were compared with previously published results. The BOD is presented for the most exposed organs.

CONCLUSION

The mean value of ESD and E varied widely among neonates. The highest number of radiographs per infant peaked 33 for chest examination in the age group 0-1 year.

Increasing utilization of computed tomography in the adult emergency department, 2000–2005

This study aims to characterize changes in computed tomography (CT) utilization in the adult emergency department (ED) over a 5-year period. CT scans ordered on adult ED patients from July 2000 to July 2005 were analyzed in five groups: head, cervical spine, chest, abdomen, and miscellaneous. ED patient volume and triage acuity scores were determined. Triage acuity scores are used to determine the severity of a patient's illness or injury and the need for immediate evaluation and treatment. There were 46,553 CT scans performed on 27,625 adult patients in the ED during the study period. During this same period, 194,622 adult patients were evaluated in the ED. From 2000 to 2005, the adult emergency department patient volume increased by 13% while triage acuity remained stable. During this same period, head CT increased by 51%, cervical spine CT by 463%, chest CT by 226%, abdominal CT by 72%, and miscellaneous CT by 132%. Although increases were generally greater for patients over age 40, the increase in those less than 40 years was also substantial. Of the 4,320 individual patients who underwent chest CT, 83 (2%) had chest CT on three or more separate ED visits. Of 10,960 patients undergoing abdominal CT, 406 (4%) had abdominal CT on three or more separate ED visits. ED CT utilization has increased at a rate far exceeding the growth in ED patient volume. This presumably reflects the improved utility of CT in diagnosing serious pathology, its increased availability, and a desire on the part of physicians for diagnostic certainty. Whether this increase in utilization results in improved patient outcomes is at present unclear and deserves additional study.

Abdominal radiograph requesting in the setting of acute abdominal pain: temporal trends and appropriateness of requesting

INTRODUCTION

The biannual turnover of house surgeons has long been dreaded by paramedical staff because of fears of increased workloads generated by 'untrained' junior doctors. The aim of this study was to address this issue by examining both the quantity and quality of requests made for emergency abdominal radiographs made by 'experienced' house surgeons during the month of July and by the 'novices' during August.

PATIENTS AND METHODS

All adult patients undergoing abdominal radiography (AXR) following admission as emergencies via the surgical directorate with abdominal signs were identified prospectively. The reports of the AXRs were reviewed to determine the total number of requests and the number of positive findings for the two groups. In addition, the hand-written request forms were recovered to determine the suitability of the requests according to nationally-accepted guidelines produced by the Royal College of Radiologists (RCR).

RESULTS

During the study period, a total of 252 radiographs were performed consisting of 98 in July and 154 in August. The number of unreported films in each month were similar at 11 (11.2%) and 16 (10.4%), respectively, leaving 87 reported radiographs in July and 138 in August. There was no difference in the number of radiographs with positive findings (excluding degenerative spinal disease) for July (n = 19; 22%) and August (n = 33; 24%). Of the 225 reported films, RCR guidelines were followed in only 73 (32%) of 225 cases. When guidelines were adhered to, positive findings were identified in 56 (76.7%) of 73 cases whereas when guidelines were not followed positive findings were seen in only 13/139 (8.9%) of AXRs.

CONCLUSIONS

We have demonstrated that the popular myth of the 'August syndrome' is unsubstantiated at least using the surrogate marker of abdominal radiograph requests. The worrying finding of a high number of unacceptable indications for the performance of abdominal radiographs deserves urgent attention both in terms of its financial implications and with regards reducing radiation exposure. A programme of education is proposed to emphasise the RCR guidelines with re-audit to assess adherence to the guidelines.

Radiation exposure in body computed tomography examinations of trauma patients

Multi-slice CT provides an efficient imaging modality for trauma imaging. The purpose of this study was to provide absorbed and effective dose data from CT taking into account the patient size and compare such doses with the standard CT dose quantities based on standard geometry. The CT examination data from abdominal and thoracic scan series were collected from 36 trauma patients. The CTDI(vol), DLP(w) and effective dose were determined, and the influence of patient size was applied as a correction factor to calculated doses. The patient size was estimated from the patient weight as the effective radius based on the analysis from the axial images of abdominal and thoracic regions. The calculated mean CTDI(vol), DLP(w) and effective dose were 15.2 mGy, 431 mGy cm and 6.5 mSv for the thorax scan, and 18.5 mGy, 893 mGy cm and 14.8 mSv for the abdomen scan, respectively. The doses in the thorax and abdomen scans taking the patient size into account were 34% and 9% larger than the standard dose quantities, respectively. The use of patient size in dose estimation is recommended in order to provide realistic data for evaluation of the radiation exposure in CT, especially for paediatric patients and smaller adults.

How many medical requests for US, body CT, and musculoskeletal MR exams in outpatients are inadequate?

PURPOSE

Our aim was to evaluate how many medical requests for US, CT and MR outpatients exams are inadequate.

MATERIALS AND METHODS

We evaluated three series of consecutive requests for outpatients exams, distinguishing firstly the adequate from the inadequate requests. The inadequate requests were classified as: (A) absence of real indication; (B) lacking or vague clinical query; (C) absence of important information on patient's status. US requests concerned 282 patients for 300 body segments, as follows: neck (n=50); upper abdomen (n=95); lower abdomen (n=12); upper and lower abdomen (n=84); musculoskeletal (n=32); other body segments (n=27). CT requests concerned 280 patients for 300 body segments, as follows: chest (n=67); abdomen (n=77); musculoskeletal (n=94); other body segments (n=62). MR musculoskeletal requests concerned 138 patients for 150 body segments, as follows: knee (n=87); ankle (n=13); shoulder (n=28) , other body segments (n=22).

RESULTS

A total of 228/300 US requests (76%) were inadequate, ranging from 66% (musculoskeletal) to 86% (neck), classified as: A, 21/228 (9%); B, 130/228 (57%); C, 77/228 (34%). A total of 231/300 (77%) body CT requests were inadequate, ranging from 72% (chest) to 86% (musculoskeletal), classified as: A, 22/231(10%); B, 88/231(38%); C, 121/231(52%). A total of 124/150 (83%) MR musculoskeletal requests were inadequate, ranging from 69% (ankle) to 89% (knee), classified as: A, 12/124(10%); B, 50/124(40%); C, 62/124 (50%). No significant difference was found among the levels of inadequacy for the three techniques and among the body segments for each of the three techniques.

CONCLUSIONS

The majority of the medical requests for outpatient exams turned out to be inadequate. A large communication gap between referring physicians and radiologists needs to be filled.

Can order of report prevent satisfaction of search in abdominal contrast studies?

RATIONALE AND OBJECTIVE

A previous receiver operating characteristic (ROC) study showed a systematic shift in decision thresholds for detecting plain film abnormalities on contrast examinations rather than plain radiographs. A previous eye-position study showed that this shift was based on a relative visual neglect of plain film regions on the contrast studies. We now determine whether an intervention that changes visual search can reduce this search-based satisfaction of search effect in contrast studies of the abdomen.

MATERIALS AND METHODS

The authors measured detection of 23 plain film abnormalities in 44 patients who had plain film and contrast examinations. In 2 experiments, each plain-film and contrast study was examined independently in different sessions with observers providing a confidence rating of abnormality for each interpretation. There were 13 observers in the first experiment and 10 in the second experiment. The intervention required that for the contrast studies, observers first report abnormalities in the noncontrast region of the radiograph before reporting contrast findings. ROC curve areas for each observer in each treatment condition were estimated by using a proper ROC model. The analysis focused on changes in decision thresholds among the treatment conditions.

RESULTS

The SOS effect on decision thresholds in abdominal contrast studies was replicated. Although reduced, the shift in decision thresholds in detecting plain film abnormalities on contrast examinations remained when observers were required to report those abnormalities before contrast findings.

CONCLUSION

Reporting plain film abnormalities before reporting abnormalities demonstrated by contrast reduced somewhat the satisfaction of search effect on decision thresholds produced by a visual neglect of noncontrast regions on contrast examinations. This suggests that interventions that direct visual search do not offer protection against satisfaction of search effects that are based on faulty visual search.

Prospective study of the clinical predictors of a positive abdominal computed tomography in blunt trauma patients

BACKGROUND

CT scans are often used in the evaluation of blunt trauma patients. Many scans are negative. Clinical predictors of positive abdominal CT scans would be beneficial in patient care.

METHODS

A prospective study of 213 patients at a Level I trauma center presenting with blunt trauma who underwent abdominal CT scan. Indications for CT scan were analyzed statistically, using univariate and multivariate models.

RESULTS

Univariate chi2 tests showed abnormal pelvis x-ray (p = 0.0002) and an intubated patient (p = 0.03) were predictors of a positive CT scan. When subjected to multivariate logistic regression, these two indications were significant predictors of a positive CT scan, abnormal pelvis x-ray (p = 0.0005, OR=6.6, 95% CI), and an intubated patient (p = 0.02, OR=2.6, 95% CI). Univariate chi2 tests also showed that alcohol intoxication was statistically significant predictor of a negative CT scan (p = 0.03).

CONCLUSION

Our data suggest that an abnormal pelvis x-ray and intubation are significant risk factors for a positive CT scan. Alcohol intoxication, mechanism of injury, and unreliable examination, without other associated indication for a scan, may warrant further study.

Sixteen–Detector Row CT of Abdomen and Pelvis: Study for Optimization of Z-Axis Modulation Technique Performed in 153 Patients

PURPOSE

To retrospectively determine the optimal noise indexes required to obtain diagnostically acceptable computed tomographic (CT) images of the abdomen and pelvis with z-axis modulation.

MATERIALS AND METHODS

Ninety-five patients underwent 16-section multi-detector row CT of the abdomen and pelvis with z-axis modulation at noise indexes of 10.5, 11.0, 11.5, and 12.0 HU with 10-380 mA. Subsequently, 58 patients were scanned at noise indexes of 12.5 and 15.0 HU with 75-380 mA. The weights of all subjects were recorded, and transverse and anteroposterior diameters were measured. The CT images were evaluated for abnormalities and graded for image quality in terms of noise and diagnostic acceptability by using a five-point scale. Objective noise in the liver parenchyma was measured, and the tube current was recorded at each section in all 153 patients. Statistical analyses were performed to determine the appropriate noise index and to assess the effect of patient weight and abdominal diameters on image noise and diagnostic acceptability at different noise indexes. Tube current-time products (in milliampere seconds) at various noise indexes were compared with those at CT previously performed without z-axis modulation.

RESULTS

No significant difference in subjective image noise or diagnostic acceptability was found at noise indexes of 10.5-15.0 HU (P =.14), and objective noise was significantly inferior only at a noise index of 15.0 HU (P =.009). Compared with CT scanning at a 10.5-HU noise index, CT scanning at 12.5- and 15.0-HU noise indexes yielded, respectively, 10.0% and 41.3% reductions in radiation exposure. Patient weight and abdominal diameters affected subjective image quality.

CONCLUSION

Use of a 15.0-HU noise index at 75-380 mA results in acceptable subjective image noise and diagnostic acceptability but significantly greater objective image noise at routine abdominal-pelvic CT. For greater image quality demands, a noise index of 12.5 HU results in acceptable image quality and a 19.6% reduction in radiation exposure.

Radiological imaging to improve the emergency department diagnosis of acute appendicitis

OBJECTIVES

To determine the institution's current non-therapeutic (negative) appendicectomy rate; the frequency of clinical predictors for appendicitis in patients who underwent appendicectomy; and the utilization and accuracy of ultrasound scans (USS) and computed tomography (CT) in the diagnosis of appendicitis.

METHODS

A retrospective chart review was conducted in an adult, metropolitan teaching hospital. Patients who presented to the ED and underwent an appendicectomy over a 12-month period were analysed. Symptoms and signs predictive of appendicitis, results of USS and CT scans if performed, and histopathology findings were abstracted from patient records.

RESULTS

Two hundred and forty patients had appendicectomies, 147 (61%) were male and the median age was 25 years (range 14-78 years). The negative appendicectomy rate was 14.3% (95% CI 9.1-21.0%) and 18.3% (95% CI 11.0-26.7%) in males and females, respectively. Abdominal pain shifting to the right iliac fossa (RIF), anorexia and RIF rebound tenderness were found more frequently in patients with positive than negative appendicectomies (P < 0.05). USS and CT scans were performed in 68 (28%) and 15 (9.5%) patients, respectively. The likelihood ratio for appendicitis in patients with a normal USS or a normal CT scan was 0.83 (95% CI 0.56-1.24) and 0.08 (95% CI 0.01-0.60), respectively. There were no false positive CT scan results.

CONCLUSION

Computed tomoraphy scanning should play an increasing role in the ED management of suspected appendicitis. Our negative appendicectomy rate could potentially be halved by the introduction of CT scans in the diagnostic work up of these patients.

Performance of helical computed tomography without oral contrast for the detection of gastrointestinal injuries

STUDY OBJECTIVE

We describe the performance of helical abdominal computed tomography (CT) scan without oral contrast for the detection of blunt gastrointestinal injuries.

METHODS

We retrospectively reviewed the records of a consecutive series of patients who underwent helical abdominal CT scanning for evaluation of blunt intra-abdominal injury and were admitted to a Level I trauma center from May 1996 to September 2001. Abdominal CT scans were performed with intravenous contrast but without oral contrast. Patients were considered to have gastrointestinal injuries if an injury was identified to the gastrointestinal tract from the duodenum to the sigmoid colon or associated mesentery and considered to have major gastrointestinal injuries if gastrointestinal perforation, active mesenteric hemorrhage, or mesenteric devascularization occurred. All gastrointestinal injuries were confirmed by laparotomy, autopsy, or additional imaging studies.

RESULTS

Six thousand fifty-two patients underwent abdominal CT scan (mean age 35.5 +/- 21.1 years), and 106 (1.8%) patients had gastrointestinal injuries identified by laparotomy, autopsy, or additional (nonabdominal CT) imaging studies. Abdominal CT scan result was abnormal in 91 (86%; 95% confidence interval [CI] 78% to 92%) of the 106 patients with gastrointestinal injuries and revealed findings suggestive of gastrointestinal injury in 81 (76%; 95% CI 67% to 84%) patients. Abdominal CT scan demonstrated findings suggestive of gastrointestinal injury in 58 of 64 (91%; 95% CI 81% to 96%) patients with major gastrointestinal injuries. Two hundred thirty-eight (4.0%) patients had findings suspicious for gastrointestinal injuries on abdominal CT scan, but gastrointestinal injury was never confirmed.

CONCLUSION

Helical abdominal CT scan without oral contrast identified nearly three fourths of patients with blunt gastrointestinal injuries who were selected for abdominal CT scanning. Sensitivity of this diagnostic test improves in the subset of patients with major gastrointestinal injuries.

Radiation from "extra" images acquired with abdominal and/or pelvic CT: effect of automatic tube current modulation

PURPOSE

To retrospectively determine the number and usefulness of images acquired beyond the intended anatomic area of interest with abdominal and/or pelvic computed tomography (CT) and to assess the effect of automatic tube current modulation (ATCM) on associated radiation.

MATERIALS AND METHODS

Superior and inferior levels at routine abdominal and/or pelvic CT were defined as the dome of the diaphragm and the inferior margin of the pubic symphysis, respectively. Records of 106 consecutive examinations (male-to-female ratio, 45:61; age range, 21-86 years) performed from June 1 to June 30, 2003, were reviewed to determine the number of "extra" images. Sixty-two abdominal and/or pelvic CT examinations performed concurrently with chest or thigh CT or for trauma were not included in the 106. Abdominal and/or pelvic CT was performed with either ATCM (n = 44) or manual selection of tube current (n = 62). CT parameters recorded for each extra image included tube current, peak kilovoltage, and gantry rotation time. Mean and median tube current-time products were calculated for extra images. Extra images were analyzed for pathologic findings. Statistical analysis was performed with the Student t test.

RESULTS

Extra images were acquired above the dome of the diaphragm in 103 (97%) of 106 examinations and below the pubic symphysis in 100 (94%) of 106. A total of 1,280 extra images were acquired in 106 examinations (mean, 12 images per examination). Nineteen additional findings were observed on extra images. With ATCM, mean tube current-time product was 74.5 and 120.6 mAs for extra images acquired above the diaphragm and below the pubic symphysis, respectively; with manual selection, mean tube current-time products were 167.5 and 168.3 mAs (P <.05).

CONCLUSION

Most extra images acquired at abdominal and/or pelvic CT contributed no additional information. With ATCM, the radiation dose was reduced by a mean of 56% (median, 72%) for extra images above the diaphragm and 29% (median, 36%) for images below the pubic symphysis, compared with dose levels with manual selection.

Interindividual variation in abdominal subcutaneous and visceral adipose tissue: influence of measurement site

We evaluated the influence of measurement site on the ranking (low to high) of abdominal subcutaneous (SAT) and visceral (VAT) adipose tissue. We also determined the influence of measurement site on the prediction of abdominal SAT and VAT mass. The subjects included 100 men with computed tomography (CT) measurements at L4–L5 and L3–L4 levels and 100 men with magnetic resonance imaging (MRI) measurements at L4–L5 and 5 cm above L4–L5 (L4–L5 +5 cm). Corresponding mass values were determined by using multiple-image protocols. For SAT, 90 and 92 of the 100 subjects for CT and MRI, respectively, had a difference in rank position at the two levels. The change in rank position exceeded the error or measurement for ∼75% of the subjects for both methods. For VAT, 91 and 95 of the 100 subjects for CT and MRI, respectively, had a difference in rank position at the two levels. The change in rank position exceeded the error of measurement for 36% of the subjects for CT and for 8% of the subjects for MRI. For both imaging modalities, the variance explained in SAT and VAT mass (kg) was comparable for L4–L5, L4–L5 +5 cm, and L3–L4 levels. In conclusion, the ranking of subjects for abdominal SAT and VAT quantity is influenced by measurement location. However, the ability to predict SAT and VAT mass by using single images obtained at the L4–L5, L4–L5 +5 cm, or L3–L4 levels is comparable.

Radiation dose to premature infants in neonatal intensive care units in Kuwait

Entrance surface dose (ESD) and effective dose (E) to premature infants were estimated at three neonatal intensive care units in Kuwait for three standard X-ray examinations--abdominal, chest and skull X rays using a simple water phantom. The ESD was found to vary between 58 and 102 microGy for abdominal X rays, between 51 and 102 microGy for chest X rays and between 58 and 145 microGy for skull examinations. These doses are comparable to the entrance skin doses published elsewhere. The E-values were estimated using normalised organ dose dataset from the National Radiological Protection Board. The E-values for abdominal, chest and skull examinations were in the ranges of 30-46, 20-36 and 8-18 microSv per examination, respectively. The risk of developing childhood cancers from each of the three examinations was estimated to be in the range (9-117) x 10(-6) for infants undergoing 25 of these X-ray examinations during their stay in the NIC unit.

Nationwide Evaluation of X-ray Trends Survey of Abdomen and Lumbosacral Spine Radiography

Results of the 1995 Nationwide Evaluation of X-ray Trends (NEXT) survey of facilities that perform diagnostic radiographic examinations of the abdomen and lumbosacral spine were compared with those of previous NEXT surveys conducted in 1987 and 1989. A clinically validated radiographic phantom was used in the 1995 survey to capture data about radiation exposure and image quality. Additional data were obtained regarding clinical techniques, facility workloads, x-ray beam quality, film processing quality, and darkroom fog. Mean skin-entrance air kerma for the abdomen examination dropped from 3.2 mGy (in 1987) to 2.8 mGy at hospitals and from 3.4 mGy (in 1989) to 3.0 mGy at nonhospital facilities. Mean skin-entrance air kerma also decreased for the lumbosacral spine examination from 3.7 mGy (in 1987) to 3.3 mGy at hospitals and from 3.8 mGy (in 1989) to 3.2 mGy at nonhospital facilities. The quality of film processing improved, although 58 (18.3%) of 317 surveyed facilities did not meet the Mammography Quality Standards Act standard for film processing quality, compared with 185 (5.9%) of 3,120 mammography facilities inspected in 1995. Finally, 181 (58.0%) of 312 surveyed facilities had darkroom fog levels greater than the Mammography Quality Standards Act standard, compared with 1,426 (16.6%) of 8,605 mammography facilities inspected in 1995.

Using sonography to examine adult patients at an academic medical center: have usage patterns changed with the expansion of managed care?

OBJECTIVE

This study was designed to determine whether significant changes have occurred in the utilization of sonography relative to more expensive cross-sectional imaging techniques in adult patients during a time of increasing reliance on managed care.

MATERIALS AND METHODS

Use of sonography was compared with use of CT and MR imaging of the abdomen, pelvis, and retroperitoneum in adult patients in 1993 and 1998 at an academic medical center. Clinicians who requested the greatest number of examinations in both years were surveyed to assess their perception of changes in their practice patterns during the interim.

RESULTS

Between 1993 and 1998, the use of sonography relative to the other cross-sectional imaging modalities decreased from 56% to 43% (p < or = 0.001). During the same time, CT use increased from 30% to 41% (p < or = 0.001), and MR imaging use increased from 14% to 16% (p < or = 0.001). Survey responses indicated that potential cost saving was not a major factor in physicians' decisions to use sonography rather than other cross-sectional imaging modalities.

CONCLUSION

Sonographic utilization decreased during a 5-year period in which managed care provided an increasingly large proportion of overall reimbursement. Cost did not appear to be a major factor in selection of diagnostic tests. Differences over time in refering clinicians' perception of the relative usefulness of sonography, CT, and MR imaging may have contributed to the change in usage patterns.