CT screening: a trade-off of risks, benefits, and costs

A dual-energy CT reconstruction method based on anchor network from dual quarter scans

Compared with conventional single-energy computed tomography (CT), dual-energy CT (DECT) provides better material differentiation but most DECT imaging systems require dual full-angle projection data at different X-ray spectra. Relaxing the requirement of data acquisition is an attractive research to promote the applications of DECT in wide range areas and reduce the radiation dose as low as reasonably achievable. In this work, we design a novel DECT imaging scheme with dual quarter scans and propose an efficient method to reconstruct the desired DECT images from the dual limited-angle projection data. We first study the characteristics of limited-angle artifacts under dual quarter scans scheme, and find that the negative and positive artifacts of DECT images are complementarily distributed in image domain because the corresponding X-rays of high- and low-energy scans are symmetric. Inspired by this finding, a fusion CT image is generated by integrating the limited-angle DECT images of dual quarter scans. This strategy enhances the true image information and suppresses the limited-angle artifacts, thereby restoring the image edges and inner structures. Utilizing the capability of neural network in the modeling of nonlinear problem, a novel Anchor network with single-entry double-out architecture is designed in this work to yield the desired DECT images from the generated fusion CT image. Experimental results on the simulated and real data verify the effectiveness of the proposed method. This work enables DECT on imaging configurations with half-scan and largely reduces scanning angles and radiation doses.

How should preoperative examinations be chosen for infants with a ventricular septal defect: transthoracic echocardiography, cardiac CTA, or a combination of these two technologies?

OBJECTIVE

To evaluate the accuracy of transthoracic echocardiography (TTE) and cardiac computed tomography angiography (CTA) in detecting the size and location of ventricular septal defects (VSD) in infants.

METHODS

Data from 258 infants diagnosed with VSD between January 2020 and December 2022 were retrospectively analyzed. All infants underwent both TTE and cardiac CTA. The accuracy of these imaging modalities was assessed by comparing their findings with intraoperative observations of VSD size and location.

RESULTS

Intraoperatively, the average VSD size was 6.1 ± 2.5 mm. The defects were classified as committed VSD (Type 1) in 45 patients, noncommitted VSD (Type 2) in 198 patients, inlet VSD (Type 3) in 12 patients, and muscular VSD (Type 4) in 3 patients. Echocardiography estimated the average VSD size at 5.6 ± 2.7 mm, with 42 patients identified as Type 1, 203 as Type 2, 10 as Type 3, and 3 as Type 4. Cardiac CTA estimated the average size at 5.9 ± 3.2 mm, with 48 patients identified as Type 1, 196 as Type 2, 11 as Type 3, and 3 as Type 4. The accuracy rates of TTE and cardiac CTA in diagnosing VSD location were 98.1% and 98.8%, respectively. A survey of surgeons indicated that 80% believe both TTE and cardiac CTA are essential preoperative evaluations.

CONCLUSIONS

TTE accurately diagnoses the size and location of VSD, while cardiac CTA serves as a valuable complementary method to TTE. Most surgeons advocate for the combined use of these examinations for preoperative assessment.

Assessing cardiovascular risk with mammography and non-contrast chest CT: A review of the literature and clinical implications

Coronary artery disease (CAD) is the leading cause of mortality and disability globally. In the United States, about 7.2% of adults aged 20 and older are affected by CAD. However, due to its progression over decades, CAD is often undetected and unnoticed until plaque ruptures. This leads to partial or complete artery blockage, resulting in myocardial infarction. Thus, new screening methods for early detection of CAD are needed to prevent and minimize the morbidity and mortality from CAD. Vascular calcifications seen on mammography and non-contrast chest CT (NCCT) can be used for the early detection of CAD and are an accurate predictor of cardiovascular risk. This paper aims to review the basic epidemiology, pathophysiology, imaging findings, and correlation of long-term cardiovascular outcomes with vascular calcifications on mammography and NCCT.

Cost-Effectiveness Analyses of Lung Cancer Screening Using Low-Dose Computed Tomography: A Systematic Review Assessing Strategy Comparison and Risk Stratification

OBJECTIVES

Our first study objective was to assess the range of lung cancer screening intervals compared within cost-effectiveness analyses (CEAs) of low-dose computed tomography (LDCT) and to examine the implications for the strategies identified as optimally cost effective; the second objective was to examine if and how risk subgroup-specific policies were considered.

METHODS

PubMed, Embase and Web of Science were searched for model-based CEAs of LDCT lung screening. The retrieved studies were assessed to examine if the analyses considered sufficient strategy variation to permit incremental estimation of cost effectiveness. Regarding risk selection, we examined if analyses considered alternative risk strata in separate analyses or as alternative risk-based eligibility criteria for screening.

RESULTS

The search identified 33 eligible CEAs, 23 of which only considered one screening frequency. Of the 10 analyses considering multiple screening intervals, only 4 included intervals longer than 2 years. Within the 10 studies considering multiple intervals, the optimal policy choice would differ in 5 if biennial intervals or longer had not been considered. Nineteen studies conducted risk subgroup analyses, 12 of which assumed that subgroup-specific policies were possible and 7 of which assumed that a common screening policy applies to all those screened.

CONCLUSIONS

The comparison of multiple strategies is recognised as good practice in CEA when seeking optimal policies. Studies that do include multiple intervals indicate that screening intervals longer than 1 year can be relevant. The omission of intervals of 2 years or longer from CEAs of LDCT screening could lead to the adoption of sub-optimal policies. There also is scope for greater consideration of risk-stratified policies which tailor screening intensity to estimated disease risk. Policy makers should take care when interpreting current evidence before implementing lung screening.

Early detection of kidney cancer using urinary proteins: a truly non-invasive strategy

OBJECTIVES

To review urinary protein biomarkers as potential non-invasive, easily obtainable, early diagnostic tools in renal cell carcinoma (RCC).

METHODS

A PubMed database search was performed up to the year 2020 to identify primary studies reporting potential urinary protein biomarkers for RCC. Separate searches were conducted to identify studies describing appropriate methods of developing cancer screening programmes and detection of cancer biomarkers.

RESULTS

Several urinary protein biomarkers are under validation for RCC diagnostics, e.g. aquaporin-1, perilipin-2, carbonic anhydrase-9, Raf-kinase inhibitory protein, nuclear matrix protein-22, 14-3-3 Protein β/α and neutrophil gelatinase-associated lipocalin. However, none has yet been validated or approved for clinical use due to low sensitivity or specificity, inconsistencies in appropriate study design, or lack of external validation.

CONCLUSIONS

Evaluation of biomarkers' feasibility, sample preparation and storage, biomarker validation, and the application of novel technologies may provide a solution that maximises the potential for a truly non-invasive biomarker in early RCC diagnostics.

Point-of-Care Ultrasound for the Diagnosis of Skull Fractures in Children Younger Than Two Years of Age

OBJECTIVES

To determine the accuracy of skull point-of-care ultrasound (POCUS) for identifying fractures in children younger than 2 years of age with signs of head trauma, and the ability of POCUS to identify the type and depth of fracture depression.

STUDY DESIGN

This was a multicenter, prospective, observational study of children younger than 2 years of age with nontrivial mechanisms of injury and signs of scalp/skull trauma. Patients were enrolled if they underwent computed tomography (CT). Patients underwent clinical evaluation, in addition to a cranial POCUS in the emergency department (ED). From the POCUS examinations, we documented whether fractures were present or absent, their location, characteristics, and depth. POCUS and CT findings were compared to calculate the diagnostic accuracy.

RESULTS

We enrolled a convenience sample of 115 of 151 (76.1%) eligible patients. Of the 115 enrolled, 88 (76.5%) had skull fractures. POCUS had a sensitivity of 80 of 88 (90.9%; 95% CI 82.9-96.0) and a specificity of 23 of 27 (85.2%; 95% CI 66.3-95.8) for identifying skull fractures. Agreement between POCUS and CT to identify the type of fracture as linear, depressed, or complex was 84.4% (97 of 115) with a kappa of 0.75 (95% CI 0.70-0.84).

CONCLUSIONS

POCUS performed by emergency physicians may identify the type and depth of fractures in infants with local physical signs of head trauma with substantial accuracy. Emergency physicians should consider POCUS as an adjunct to clinical evaluation and prediction rules for traumatic brain injuries in children younger than 2 years of age.

Wide-field Raman imaging for bone detection in tissue

Inappropriate bone growth in soft tissue can occur after trauma to a limb and can cause a disruption to the healing process. This is known as Heterotopic Ossification (HO) in which regions in the tissue start to mineralize and form microscopic bone-like structures. These structures continue to calcify and develop into large, non-functional bony masses that cause pain, limit limb movement, and expose the tissue to reoccurring infections; in the case of open wounds this can lead to amputation as a result of a failed wound. Both Magnetic Resonance Imaging (MRI) and X-ray imaging have poor sensitivity and specificity for the detection of HO, thus delaying therapy and leading to poor patient outcomes. We present a low-power, fast (1 frame per second) optical Raman imaging system with a large field of view (1 cm(2)) that can differentiate bone tissue from soft tissue without spectroscopy, this in contrast to conventional Raman microscopy systems. This capability may allow for the development of instrumentation which permits bedside diagnosis of HO.

Economic evaluation of colorectal cancer (CRC) screening

Because of its incidence and mortality colorectal cancer represents a serious public health issue in industrial countries. In order to reduce its social impact a number of screening strategies have been implemented, which allow an early diagnosis and treatment. These basically include faecal tests and studies that directly explore the colon and rectum. No strategy, whether alone or combined, has proven definitively more effective than the rest, but any such strategy is better than no screening at all. Selecting the most efficient strategy for inclusion in a population-wide program is an uncertain choice. Here we review the evidence available on the various economic evaluations, and conclude that no single method has been clearly identified as most cost-effective; further research in this setting is needed once common economic evaluation standards are established in order to alleviate the methodological heterogeneity prevailing in study results.

From accuracy to patient outcome and cost-effectiveness evaluations of diagnostic tests and biomarkers: an exemplary modelling study

BACKGROUND

Proper evaluation of new diagnostic tests is required to reduce overutilization and to limit potential negative health effects and costs related to testing. A decision analytic modelling approach may be worthwhile when a diagnostic randomized controlled trial is not feasible. We demonstrate this by assessing the cost-effectiveness of modified transesophageal echocardiography (TEE) compared with manual palpation for the detection of atherosclerosis in the ascending aorta.

METHODS

Based on a previous diagnostic accuracy study, actual Dutch reimbursement data, and evidence from literature we developed a Markov decision analytic model. Cost-effectiveness of modified TEE was assessed for a life time horizon and a health care perspective. Prevalence rates of atherosclerosis were age-dependent and low as well as high rates were applied. Probabilistic sensitivity analysis was applied.

RESULTS

The model synthesized all available evidence on the risk of stroke in cardiac surgery patients. The modified TEE strategy consistently resulted in more adapted surgical procedures and, hence, a lower risk of stroke and a slightly higher number of life-years. With 10% prevalence of atherosclerosis the incremental cost-effectiveness ratio was € 4,651 and € 481 per quality-adjusted life year in 55-year-old men and women, respectively. In all patients aged 65 years or older the modified TEE strategy was cost saving and resulted in additional health benefits.

CONCLUSIONS

Decision analytic modelling to assess the cost-effectiveness of a new diagnostic test based on characteristics, costs and effects of the test itself and of the subsequent treatment options is both feasible and valuable. Our case study on modified TEE suggests that it may reduce the risk of stroke in cardiac surgery patients older than 55 years at acceptable cost-effectiveness levels.

Abdominal aortic aneurysm: an often asymptomatic and fatal men's health issue

Men are more likely than women to develop an abdominal aortic aneurysm (AAA), a disease that is often asymptomatic and has up to a 90% risk of mortality if the aneurysm ruptures. What many men do not know is that an AAA can easily be identified through an ultrasound screening, and if the aneurysm is >5.5 cm, it can be surgically repaired to prevent a life-threatening rupture. Although current AAA screening recommendations focus on men between the ages of 65 and 75 years, who have ever smoked, recent evidence suggest many men of ages 50 to 80 years, regardless of smoking status, may also be at risk for developing an AAA. This article presents a comprehensive overview of AAA disease and summarizes current evidence-based diagnostic and treatment guidelines, the importance of educating men about this health issue, and the need for more widespread AAA ultrasound screening opportunities.

Absolute value of visceral fat area measured on computed tomography scans and obesity-related cardiovascular risk factors in large-scale Japanese general population (the VACATION-J study)

BACKGROUND

The management of cardiovascular risk factors is important for prevention of atherosclerotic cardiovascular diseases (ACVD). Visceral fat accumulation plays an important role in the clustering of cardiovascular risk factors, leading to ACVD. The present study investigated the gender- and age-specific relationship between obesity-related cardiovascular risk factor accumulation and computed tomography (CT)-measured fat distribution in a large-scale Japanese general population.

METHODS AND RESULTS

Fat distribution was measured on CT scans in 12,443 subjects (males/females = 10,080/2,363), who underwent medical health check-up at 9 centers in Japan. The investigated obesity-related cardiovascular risk factors were hyperglycemia, dyslipidemia, and elevated blood pressure. Visceral fat area (VFA) for all males and old females showed almost symmetric distribution, while that of young females showed skewed distribution with a marked left shift. Only a small proportion of young females had large visceral fat and cardiovascular risk accumulation. The mean number of risk factors exceeded 1.0 at around 100 cm(2) for VFA in all groups, irrespective of gender, age (cut-off age 55), and BMI (cut-off BMI 25 kg/m(2)).

CONCLUSIONS

In this large-scale Japan-wide general population study, an absolute VFA value of about 100 cm(2) equated with obesity-related cardiovascular risk factor accumulation, irrespective of gender, age, and BMI.

Qualitative score of systemic arteriosclerosis by vascular ultrasonography as a predictor of coronary artery disease in type 2 diabetes

OBJECTIVE

Patients with type 2 diabetes mellitus (T2DM) are at risk of polyvascular comorbidities and poor prognosis. Non-invasive techniques for early prediction of coronary artery disease (CAD) are desirable to prevent cardiovascular events in these patients. The aim of the present study was to investigate the association between CAD and systemic arteriosclerosis by qualitative vascular ultrasonography.

METHODS

The study subjects were 102 consecutive outpatients with T2DM [males/females = 60/42, age: mean ± SD 67 ± 9 (range, 40-85) years] evaluated by vascular ultrasonography for arteriosclerosis in the abdominal aorta, carotid, renal, and common iliac arteries. The total number of detected arteriosclerotic vascular lesions in the four arteries was determined. CAD was diagnosed by two cardiologists using either stress electrocardiography, myocardial scintigraphy, multi-detector row computed tomography or coronary angiography.

RESULTS

Multiple arteriosclerotic vascular lesions (>1) were detected in 64 (63%) patients. The total systemic vascular score was significantly higher in patients with CAD than those without (average score 2.7 versus 1.0, p < 0.0001). None of the CAD patients had a total score of 0. Age- and sex-adjusted multiple logistic regression analysis identified total score of ≥ 2 as the only predictor of CAD (p < 0.001). The sensitivity, specificity, positive and negative predictive values for total systemic vascular score in the prediction of CAD were 98%, 77%, 83%, and 97%, respectively, which were better than those for carotid mean and maximum intima-media thickness.

CONCLUSION

Non-invasive qualitative evaluation of systemic arteriosclerosis by the total systemic vascular score is potentially useful for the early prediction of CAD in T2DM patients.

Impact of whole-body CT screening on the cost-effectiveness of CT colonography

PURPOSE

To analyze the impact of adding computed tomographic (CT) imaging of the chest on the clinical effectiveness and cost-effectiveness of CT colonography to determine whether performing CT colonography and whole-body CT is a more clinically and cost-effective strategy than CT colonography alone when screening average-risk subjects.

MATERIALS AND METHODS

A Markov model simulated the occurrence of colorectal neoplasia, extracolonic abominal-pelvic malignancy, lung cancer, coronary artery disease (CAD), and abdominal aortic aneurysm (AAA) in a cohort of 100,000 U.S. subjects aged 50 to 100 years. Cost-effectiveness of CT colonography and whole-body CT was compared with that of CT colonography alone; each test was assumed to be repeated every 10 years between ages of 50 and 80 years.

RESULTS

Performing CT colonography and whole-body CT was more effective and costly than was CT colonography alone. The addition of chest CT was associated with a 22% increase in efficacy (life-years gained: 14,662 vs 11,990) and with a 48% increase in cost per person ($13,605 vs $9,223). Both strategies were cost effective as compared with no screening, with an incremental cost-effectiveness ratio (ICER) of $17,672 (CT colonography alone) and $44,337 (CT colonography and whole-body CT), respectively, but performing CT colonography and whole-body CT was not a cost-effective option when compared with CT colonography alone (ICER, $164,020). This was mainly a result of the high cost of false-positive follow-up for CAD and to the poor efficacy of lung cancer screening. Expected value of perfect information was $520 per patient.

CONCLUSION

The addition of chest CT to CT colonography does not appear to be a cost-effective alternative. Further research is needed before whole-body CT can be recommended in clinical practice.

The use of CT for screening: a national survey of radiologists' activities and attitudes

PURPOSE

To investigate the activities, motivations, and attitudes of radiologists regarding specific computed tomographic (CT) screening examinations by using a survey.

MATERIALS AND METHODS

All study activities were approved by the institutional review board. A self-administered, mailed survey was used to collect data on the practices and attitudes of U.S. radiologists regarding three CT screening tests--coronary artery calcium scoring (CACS), lung cancer screening CT, and whole-body screening CT. The survey was sent to 1000 diagnostic radiologists who were randomly sampled from the American Medical Association Physician Masterfile.

RESULTS

A total of 398 (41.4%) of 961 eligible radiologists completed the survey. Among respondents, 33.6% reported reading CT screening studies, the most common being CACS (26.7%), followed by lung screening (19.2%) and whole-body screening (9.5%). Among respondents, 34.1% supported CACS and 29.9% supported lung CT screening for particular patients, while 1.9% supported whole-body CT screening. The most common reasons reported for reading CT screening studies were responses to requests from physicians (83.3%) or patients (75.0%), while fewer (40.8%) cited patient benefit from screening as a reason.

CONCLUSION

A substantial proportion of a nationally representative sample of radiologists in the United States reads CT screening studies of the heart, lungs, and whole body and holds favorable attitudes toward CACS and lung CT screening. These attitudes may allow for the premature diffusion of new screening tests into practice before higher-level evidence demonstrates their benefits for population mortality.

Could CT screening for lung cancer ever be cost effective in the United Kingdom?

Background

The absence of trial evidence makes it impossible to determine whether or not mass screening for lung cancer would be cost effective and, indeed, whether a clinical trial to investigate the problem would be justified. Attempts have been made to resolve this issue by modelling, although the complex models developed to date have required more real-world data than are currently available. Being founded on unsubstantiated assumptions, they have produced estimates with wide confidence intervals and of uncertain relevance to the United Kingdom.

Method

I develop a simple, deterministic, model of a screening regimen potentially applicable to the UK. The model includes only a limited number of parameters, for the majority of which, values have already been established in non-trial settings. The component costs of screening are derived from government guidance and from published audits, whilst the values for test parameters are derived from clinical studies. The expected health gains as a result of screening are calculated by combining published survival data for screened and unscreened cohorts with data from Life Tables. When a degree of uncertainty over a parameter value exists, I use a conservative estimate, i.e. one likely to make screening appear less, rather than more, cost effective.

Results

The incremental cost effectiveness ratio of a single screen amongst a high-risk male population is calculated to be around £14,000 per quality-adjusted life year gained. The average cost of this screening regimen per person screened is around £200. It is possible that, when obtained experimentally in any future trial, parameter values will be found to differ from those previously obtained in non-trial settings. On the basis both of differing assumptions about evaluation conventions and of reasoned speculations as to how test parameters and costs might behave under screening, the model generates cost effectiveness ratios as high as around £20,000 and as low as around £7,000.

Conclusion

It is evident that eventually being able to identify a cost effective regimen of CT screening for lung cancer in the UK is by no means an unreasonable expectation.

Predictors of non-calcified plaques in the coronary arteries of 242 subjects using multislice computed tomography and logistic regression models

OBJECTIVES

We detected non-calcified plaques (NCPs) in the coronary arteries using multislice computed tomography (MSCT) in order to determine the predictors of NCPs using logistic regression models.

METHODS

Two hundred and forty-two consecutive subjects (141 males; overall age range, 17-91 years old) underwent enhanced electrocardiogram-gated MSCT to detect NCPs. Logistic models for predicting NCPs were developed which incorporated age, sex, coronary calcified-plaque (CP), and the following coronary risk factors (RFs): hypertension (HT), diabetes mellitus (DM), hyperlipidemia (HL), a smoking habit, and obesity.

RESULTS

NCPs were detected in 76 subjects (59 males, 35-82 years old [median=67]) whose average number of coronary RFs was 2.6, 75% of whom presented with HT, 30% with DM, 51% with HL, 64% were present or past cigarette smokers, and 32% were obese. In the 76 subjects with NCPs, the incidence of male sex, presence of HT, a smoking habit, CP and the number of coronary RFs were significantly higher than in the 166 subjects without NCP. Of the 101 female subjects, 17 showed NCPs and in every case the subject was more than 50 years old. In a logistic regression model, male sex, HT and smoking habit (relative risks 2.7, 2.0, and 2.7 [95% confidence interval=1.3-5.6, 1.0-4.0, and 1.5-4.9, respectively]) were associated with increased incidence of NCPs.

CONCLUSIONS

The incidence of NCPs was significantly increased in the presence of HT and a smoking habit, suggesting that lesions may be caused by HT or smoking-induced vessel injury even in the young male.

Direction, location, and size of shunt flow in congenital heart disease evaluated by ECG-gated multislice computed tomography

OBJECTIVE

To demonstrate the utility of multislice computed tomography (MSCT) in the evaluation of direction, location, and size of shunt flow in congenital heart disease.

BACKGROUND

Transthoracic and transesophageal echocardiography, magnetic resonance imaging, and conventional angiography has been used to evaluate congenital heart disease; however, some are invasive and some do not provide accurate information about the spatial relationship to other organs.

METHODS

Three patients with typical presentation of ventricular septal defect, atrial septal defect, and patent ductus arteriosus were recruited. Enhanced MSCT (Light Speed Ultra 16, General Electric) was performed with a 1.25-mm slice thickness, helical pitch 3.25. Following intravenous injection of 100 ml of iodinated contrast material (350 mg I/ml) at a rate of 3 ml/s, CT scanning was performed with retrospective ECG-gated reconstruction at 5 s and 30 s after injection.

RESULTS

In all cases the information of direction, location, and size of shunt flow including left-to-right and right-to-left shunt with spatial relationship to other organs could be obtained non-invasively.

CONCLUSION

ECG-gated MSCT is a useful tool to evaluate congenital heart diseases with shunts.

Influence of heart rate on the detectability and reproducibility of multislice computed tomography for measuring coronary calcium score using a pulsating calcified mock-vessel in comparison with electron beam tomography

BACKGROUND

The influence of heart rate on detectability and reproducibility of multislice computed tomography (MSCT) for measuring coronary calcium score was evaluated using pulsating calcified mock-vessels and compared with electron beam tomography (EBT).

MATERIALS AND METHODS

Four calcified mock-vessels with 200-350 HU were made to pulsate at a rate of 40-80 beat/min. Retrospective ECG-gating MSCT (Light Speed Ultra 16) scanning with 0.625 mm slice-thickness was performed twice at each pulsation rate. For comparison, EBT (Imatron C150 XP) was performed with 3 and 1.5 mm beam collimation with prospective ECG-gating and calcium scores were measured.

RESULTS

The comparison revealed that MSCT did not have better reproducibility than EBT, but the calcium scores with MSCT were less influenced by pulsation rates than those with EBT. Especially in mild calcification, the calcium scores decreased with EBT with 3 mm beam collimation with increasing pulsation rate, but the scores were stable in any rate with MSCT.

CONCLUSION

MSCT effectively detects coronary calcification, especially mild calcification, without being influenced by heart rate. This is accomplished by reducing the partial volume effect in the through plane using sub millimeter slice thickness, and using appropriate reconstruction methods, which improve temporal resolution.

Emerging techniques: Whole-body screening and staging with MRI

Strategies for screening or tumor staging include various modalities such as plain radiography, computed tomography (CT), MRI, and ultrasound. Technical innovations have created the feasibility to use MRI to image the entire body in a relatively short time-period. Whole-body MRI may play a potentially important role in evaluating for cancer or vascular disease. This article describes the rationale for using MRI to display the entire body, the techniques employed in whole-body MRI, possibilities and limitations, and summarizes first clinical results for screening and staging purposes.

Routine histopathology in uncomplicated sinus surgery: is it necessary?

OBJECTIVE

To evaluate the incidence of occult pathology in routine, uncomplicated endoscopic sinus surgery, and to suggest guidelines for when to send specimens for histopathologic exam.

STUDY DESIGN AND SETTING

Retrospective analysis of case records of 790 patients who underwent 868 endoscopic sinus surgeries at a tertiary care center from 1986 to 2003. Indications were chronic sinusitis, recurrent acute sinusitis, nasal polyposis, or combinations of these diagnoses. All cases were considered routine and did not involve preoperative suspicion of neoplasm or other complicating factors. Charts were reviewed for surgical indication, patient age, laterality of disease, history of prior sinus surgery, intraoperative suspicion of tumor, and final histopathology.

RESULTS

In 868 cases of endoscopic sinus surgery, occult neoplasm was diagnosed in 2 patients (0.23%). In one patient, the initial surgery cured the lesion. Final histopathology of the remaining 866 (99.8%) specimens was consistent with inflammation and/or nasal polyposis. In 121 cases of unilateral sinusitis, none was positive for neoplasm. In 277 cases involving bilateral nasal polyposis and 13 involving unilateral polyposis, no neoplasms were found. Intraoperative suspicion of neoplasm occurred in 12 cases, with all specimens read as consistent with sinusitis and/or polyposis.

CONCLUSIONS

Histopathologic review of every specimen obtained in routine sinus surgery for sinusitis and/or nasal polyposis is not indicated. Submission of specimen is indicated in routine cases when: 1) there is intraoperative suspicion of tumor, 2) unilateral nasal polyposis is present, 3) unilateral sinus opacification is present, and 4) additional diagnostic information is needed (eg, presence of eosinophils, fungal forms, etc.).

SIGNIFICANCE

Establishes a safe and reasonable standard of care, with potential cost savings and medico-legal ramifications.

Whole-body magnetic resonance imaging

Whole-body magnetic resonance imaging is a fast and accurate modality for the detection of disease throughout the entire body. Technical improvements including the availability of different high image quality MR sequences, the remote movement of the imaging table, and the use of specialized surface coils have rendered whole-body screening with MRI a feasible method. In this article we describe underlying techniques and report on first clinical experiences of whole-body magnetic resonance imaging as a staging and screening method. Furthermore, advantages and limitations compared with whole-body imaging based on computed tomography are discussed.

Cardiovascular Circulation and Hepatic Perfusion of Pigs in 4-Dimensional Films Evaluated by 256-Slice Cone-Beam Computed Tomography

BACKGROUND

In both cardiac and hepatic disorders it is desirable to accurately visualize the direction and scale of blood flow in the whole organ in pulsating 3-dimensional (D) images, which are known as 4-D images.

METHODS AND RESULTS

The present study used 256-slice cone-beam computed tomography (CT) (Athena, Sony-Toshiba) at one rotation per second and a section thickness of 0.5 mm to show the dynamics of cardiovascular circulation and hepatic perfusion by contrast injection in 4-D films of pigs. Four pigs (20 kg each) were anesthetized with isoflurane. The distal tips of the catheters were positioned in the inferior vena cava (IVC) (pigs 1-3) and in the proper hepatic artery (pig 4). Volumetric scanning and injection of contrast material were started simultaneously and continued for 25 s with image reconstruction at 1-s intervals. In pigs 1-3, 4-D filming revealed the dynamics of cardiovascular circulation, first in the IVC, followed by the right ventricle and pulmonary artery, then the left ventricle, left atrium, pulmonary vein, and finally, the right heart disappeared and only the left heart and aorta remained visible. In pig 4, the hepatic arterial trees, followed by the venous trees, could be easily visualized in turn on the 4-D images.

CONCLUSIONS

This technology successfully demonstrated cardiovascular circulation and hepatic perfusion in 4-D and will have clinical applicability.

Cancer imaging: is it cost-effective?

With expenditure on imaging patients with cancer set to increase in line with rising cancer prevalence, there is a need to demonstrate the cost-effectiveness of advanced cancer imaging techniques. Cost-effectiveness studies aim to quantify the cost of providing a service relative to the amount of desirable outcome gained, such as improvements in patient survival. Yet, the impact of imaging on the survival of patients with cancer is small compared to the impact of treatment and is therefore hard to measure directly. Hence, techniques such as decision-tree analysis, that model the impact of imaging on survival, are increasingly used for cost-effectiveness evaluations. Using such techniques, imaging strategies that utilise computed tomography, magnetic resonance imaging and positron emission tomography have been shown to be more cost-effective than non-imaging approaches for the management of certain cancers including lung, prostate and lymphoma. There is stronger evidence to support the cost-effectiveness of advanced cancer imaging for diagnosis, staging and monitoring therapy than for screening. The results of cost-effectiveness evaluations are not directly transferable between countries or tumour types and hence more studies are needed. As many of the techniques developed to assess the evidence base for therapeutic modalities are not readily applicable to diagnostic tests, cancer imaging specialists need to define the methods for health technology assessment that are most appropriate to their speciality.