Dynamic contrast-enhanced CT compared with positron emission tomography CT to characterise solitary pulmonary nodules: the SPUtNIk diagnostic accuracy study and economic modelling

BACKGROUND

Current pathways recommend positron emission tomography-computerised tomography for the characterisation of solitary pulmonary nodules. Dynamic contrast-enhanced computerised tomography may be a more cost-effective approach.

OBJECTIVES

To determine the diagnostic performances of dynamic contrast-enhanced computerised tomography and positron emission tomography-computerised tomography in the NHS for solitary pulmonary nodules. Systematic reviews and a health economic evaluation contributed to the decision-analytic modelling to assess the likely costs and health outcomes resulting from incorporation of dynamic contrast-enhanced computerised tomography into management strategies.

DESIGN

Multicentre comparative accuracy trial.

SETTING

Secondary or tertiary outpatient settings at 16 hospitals in the UK.

PARTICIPANTS

Participants with solitary pulmonary nodules of ≥ 8 mm and of ≤ 30 mm in size with no malignancy in the previous 2 years were included.

INTERVENTIONS

Baseline positron emission tomography-computerised tomography and dynamic contrast-enhanced computer tomography with 2 years' follow-up.

MAIN OUTCOME MEASURES

Primary outcome measures were sensitivity, specificity and diagnostic accuracy for positron emission tomography-computerised tomography and dynamic contrast-enhanced computerised tomography. Incremental cost-effectiveness ratios compared management strategies that used dynamic contrast-enhanced computerised tomography with management strategies that did not use dynamic contrast-enhanced computerised tomography.

RESULTS

A total of 380 patients were recruited (median age 69 years). Of 312 patients with matched dynamic contrast-enhanced computer tomography and positron emission tomography-computerised tomography examinations, 191 (61%) were cancer patients. The sensitivity, specificity and diagnostic accuracy for positron emission tomography-computerised tomography and dynamic contrast-enhanced computer tomography were 72.8% (95% confidence interval 66.1% to 78.6%), 81.8% (95% confidence interval 74.0% to 87.7%), 76.3% (95% confidence interval 71.3% to 80.7%) and 95.3% (95% confidence interval 91.3% to 97.5%), 29.8% (95% confidence interval 22.3% to 38.4%) and 69.9% (95% confidence interval 64.6% to 74.7%), respectively. Exploratory modelling showed that maximum standardised uptake values had the best diagnostic accuracy, with an area under the curve of 0.87, which increased to 0.90 if combined with dynamic contrast-enhanced computerised tomography peak enhancement. The economic analysis showed that, over 24 months, dynamic contrast-enhanced computerised tomography was less costly (£3305, 95% confidence interval £2952 to £3746) than positron emission tomography-computerised tomography (£4013, 95% confidence interval £3673 to £4498) or a strategy combining the two tests (£4058, 95% confidence interval £3702 to £4547). Positron emission tomography-computerised tomography led to more patients with malignant nodules being correctly managed, 0.44 on average (95% confidence interval 0.39 to 0.49), compared with 0.40 (95% confidence interval 0.35 to 0.45); using both tests further increased this (0.47, 95% confidence interval 0.42 to 0.51).

LIMITATIONS

The high prevalence of malignancy in nodules observed in this trial, compared with that observed in nodules identified within screening programmes, limits the generalisation of the current results to nodules identified by screening.

CONCLUSIONS

Findings from this research indicate that positron emission tomography-computerised tomography is more accurate than dynamic contrast-enhanced computerised tomography for the characterisation of solitary pulmonary nodules. A combination of maximum standardised uptake value and peak enhancement had the highest accuracy with a small increase in costs. Findings from this research also indicate that a combined positron emission tomography-dynamic contrast-enhanced computerised tomography approach with a slightly higher willingness to pay to avoid missing small cancers or to avoid a 'watch and wait' policy may be an approach to consider.

FUTURE WORK

Integration of the dynamic contrast-enhanced component into the positron emission tomography-computerised tomography examination and the feasibility of dynamic contrast-enhanced computerised tomography at lung screening for the characterisation of solitary pulmonary nodules should be explored, together with a lower radiation dose protocol.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018112215 and CRD42019124299, and the trial is registered as ISRCTN30784948 and ClinicalTrials.gov NCT02013063.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 17. See the NIHR Journals Library website for further project information.

Comparative accuracy and cost-effectiveness of dynamic contrast-enhanced CT and positron emission tomography in the characterisation of solitary pulmonary nodules

INTRODUCTION

Dynamic contrast-enhanced CT (DCE-CT) and positron emission tomography/CT (PET/CT) have a high reported accuracy for the diagnosis of malignancy in solitary pulmonary nodules (SPNs). The aim of this study was to compare the accuracy and cost-effectiveness of these.

METHODS

In this prospective multicentre trial, 380 participants with an SPN (8-30 mm) and no recent history of malignancy underwent DCE-CT and PET/CT. All patients underwent either biopsy with histological diagnosis or completed CT follow-up. Primary outcome measures were sensitivity, specificity and overall diagnostic accuracy for PET/CT and DCE-CT. Costs and cost-effectiveness were estimated from a healthcare provider perspective using a decision-model.

RESULTS

312 participants (47% female, 68.1±9.0 years) completed the study, with 61% rate of malignancy at 2 years. The sensitivity, specificity, positive predictive value and negative predictive values for DCE-CT were 95.3% (95% CI 91.3 to 97.5), 29.8% (95% CI 22.3 to 38.4), 68.2% (95% CI 62.4% to 73.5%) and 80.0% (95% CI 66.2 to 89.1), respectively, and for PET/CT were 79.1% (95% CI 72.7 to 84.2), 81.8% (95% CI 74.0 to 87.7), 87.3% (95% CI 81.5 to 91.5) and 71.2% (95% CI 63.2 to 78.1). The area under the receiver operator characteristic curve (AUROC) for DCE-CT and PET/CT was 0.62 (95% CI 0.58 to 0.67) and 0.80 (95% CI 0.76 to 0.85), respectively (p<0.001). Combined results significantly increased diagnostic accuracy over PET/CT alone (AUROC=0.90 (95% CI 0.86 to 0.93), p<0.001). DCE-CT was preferred when the willingness to pay per incremental cost per correctly treated malignancy was below £9000. Above £15 500 a combined approach was preferred.

CONCLUSIONS

PET/CT has a superior diagnostic accuracy to DCE-CT for the diagnosis of SPNs. Combining both techniques improves the diagnostic accuracy over either test alone and could be cost-effective.

TRIAL REGISTRATION NUMBER

NCT02013063.

Establishing local diagnostic reference levels for common orthopaedic procedures using the mini C-arm fluoroscope

OBJECTIVE

Mini C-arm fluoroscopes are widely used by orthopaedic surgeons for intraoperative image guidance without the need for radiographers. This puts the responsibility for radiation exposure firmly with the operating surgeon. In order to maintain safe and best practice under U.K. Ionising Radiation (Medical Exposure) Regulations, one must limit radiation exposure and audit performance using national diagnostic reference levels (DRLs). In the case of the mini C-arm, there are no national DRLs. IR(ME)R, therefore, require the establishment of local DRLs by each hospital to act as an alternative guideline for safe radiation use. The aim of our audit was to establish local DRLs based on our experience operating with the use of the mini C-arm over the last 7 years.

METHODS

This retrospective audit evaluates the end dose-area product (DAP) recorded for common trauma and orthopaedic procedures using the mini C-arm in a busy district general hospital.We present the quartile data and have set the cut-off point as the third quartile for formulating the local DRLs, consistent with the methodology for the conventional fluoroscope.

RESULTS

For our data set (n = 1664), the third quartile DAP values were lowest for surgeries to the forearm (5.38 cGycm²), hand (7.62 cGycm²), and foot/ankle (8.56 cGycm²), and highest for wrist (10.64 cGycm²) and elbow (14.61 cGycm²) procedures.

ADVANCES IN KNOWLEDGE

To our knowledge, this is the largest data set used to establish local DRLs. Other centres may find our guidelines useful whilst they establish their own local DRLs.

Accuracy and cost-effectiveness of dynamic contrast-enhanced CT in the characterisation of solitary pulmonary nodules-the SPUtNIk study

INTRODUCTION

Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrast-enhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently.

METHODS AND ANALYSIS

The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) (18FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for 18FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs.

ETHICS AND DISSEMINATION

Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN30784948; Pre-results.

Cortical excitability and age-related volumetric MRI changes

OBJECTIVE

Normative data on transcranial magnetic stimulation (TMS)-derived measures of cortical excitability in the elderly is sparse. Nevertheless, elderly subjects are included as controls in studies utilizing TMS to investigate disease states. Age-associated increased ventricular cerebrospinal fluid CSF (vCSF) and white matter hyperintensity (WMH) MRI volumes have uncertain significance in non-demented elderly. Information regarding cortical excitability in neurologically intact elderly would augment our understanding of the pathophysiology of aging and assist in the interpretation of TMS studies involving elderly subjects.

METHODS

Twenty-four healthy elderly subjects underwent TMS testing to determine outcomes of resting motor threshold (RMT) cortical silent period (cSP) and central motor conduction time for examination in relation to WMH, vCSF, and CNS volumes.

RESULTS

Increased vCSF and WMH volumes were associated with decreased right and left hemisphere RMT. Smaller CNS volumes were associated with decreased right hemisphere RMT and shorted cSP.

CONCLUSIONS

Commonly observed age-associated MRI changes are associated with findings consistent with increased cortical excitability.

SIGNIFICANCE

Age-related MRI findings likely reflect changes at a cellular level, and may influence cognitive and motor integrity in the elderly. Future TMS studies investigating cortical excitability may wish to consider neuroimaging markers of neurodegeneration prior to enrolling elderly subjects as controls.

Distal scaphoid resection arthroplasty for the treatment of degenerative arthritis secondary to scaphoid nonunion

Nineteen patients with chronic scaphoid nonunion and associated degenerative arthritis between the distal fragment and the radial styloid were treated by resection of the distal fragment. All patients had a dorsal intercalated segment instability wrist collapse pattern with an average radiolunate angle of -32 degrees and a 10% reduction in the carpal height, both of which changed minimally during the follow-up period. The duration of the nonunion averaged 12 years and the follow-up period averaged 49 months. Range of motion improved 85% and grip improved 134%. Thirteen of the patients experienced complete pain relief. One patient required additional surgery and elected wrist arthrodesis. Resection of the distal fragment is not recommended for patients with capitolunate arthritis. Two of the 4 patients with capitolunate arthritis had persistent symptoms; 3 had progressive degenerative changes.

In vitro interleukin-1 and tumor necrosis factor-alpha production by macrophages from chickens infected with either Eimeria maxima or Eimeria tenella

We measured the in vitro production of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF- ) by macrophages from chickens during and immediately following an infection with one of two different species of Eimeria, E. maxima and E. tenella. Quantitatively, the amounts of IL-1 produced during each infection were nearly identical regardless of the oocyst dose of each parasite. TNF production followed a biphasic pattern of increased production with the first peak associated with the pathogenesis of disease and the second peak associated with the development of protective immunity. These experiments together with others we have reported imply cells taken from chickens infected with coccidia have a greater capacity to produce cytokines upon stimulation in vitro than cells from non-infected birds. The production of significantly greater amounts of TNF during the days 3-6 after inoculation correlates with the appearance of the most characteristic local and systemic pathophysiological changes in the host induced by the coccidia. The excessive release of TNF in response to a heavy coccidial infection may account for many of the pathological features observed with avian coccidiosis probably through the release of other mediators.

Abnormalities of antibody production after thermal injury. An association with reduced interleukin 2 production

Antibody (Ab) production was studied in 25 burned patients who were immunized with 0.5 mg of tetanus toxoid adsorbed. Anti-tetanus toxoid (TT) Ab was measured by hemagglutination, radial immunodiffusion, and an enzyme-linked immunosorbent assay, and the results for the patients were compared with those for five similarly immunized healthy controls. As measured by hemagglutination, 12 (63%) of 19 patients had lower Ab responses than all five controls (P less than .05 by chi 2), and the median Ab response during the period of maximum response was significantly less than that in controls (8 vs 15.5 log2 maximum dilution; P = .014). After the initial response, serum Ab levels were not maintained in patients, in contrast to controls. This pattern was demonstrated by all three assays; enzyme-linked immunosorbent assay demonstrated that IgG anti-TT Ab was the major class of Ab produced. In nine patients interleukin 2 production by T lymphocytes was measured simultaneously; it was significantly depressed throughout the study except during the period from 36 to 45 days. The Ab response was also impaired in this patient group. Since maintained antibody production in response to TT is known to be T-cell dependent, these results suggest that inadequate interleukin 2 production leading to reduced T-cell help may be responsible for the lack of a persistent Ab response in these burned patients.

Reconstruction of acetabular deficiency utilizing iliac bone graft

ABSTRACT; Acetabular reconstructions were performed on 12 hips possessing deficient acetabuli. Eleven required total hip arthroplasties for relief of pain; seven of which were surface replacements. The one remaining h ip had erosion of the posterior wall, secondary to spastic paraparesis, and the posterior wall was reconstructed. The etiologies of the deficient acetabuli included five secondary to fracture/dislocation, four with acetabular dysplasias, and three related to failed acetabular components from conventional total hip arthroplasties. There were six posterior Hp deficiencies, five superior rim deficiencies, and one central deficiency. The iliac crest provided the graft material utilized in 11 of 12 cases; in one case the femoral head was used for reconstruction. All peripheral defects, however, were handled similarly regardless of the source of graft material, in that all grafts were secured with at least two cortical cancellous screws lagged for compression. Central defects utilized single cortex grafts keyed into the defect upon a bed of cancellous graft and rimmed with methyl methacrylate. All patients were followed at routine intervals; the shortest followup was 14 months, and the longest 32 months. All grafts showed radiographic evidence of union by one year. Three-phase bone scans were routinely done in patients undergoing surface replacement by one year. The scan appearance of the femoral head was identical to other uncomplicated surface replacements. The grafted area showed increased uptake.The purpose of this report is twofold: to present iliac crest as a graft material from which deficient acetabuli can be reconstructed when autogenous femoral head is not available, and to offer a fixation technique potentially less demanding and yet no less secure than those previously suggested. The results of this study indicate that, in selected situations, iliac crest graft acetabuloplasty can be successfully employed so that the total hip arthroplasties may be performed reducing fear of premature acetabular loosening related to insufficient bony coverage of the acetabular component.

Analysis of revision surgery of resurfacing hip arthroplasty

Results of revision of 24 resurfacing hip prostheses followed up for a minimum of one year are encouraging. The average Iowa Hip Rating after salvage was higher than the average highest rating prior to failure of the original resurfacing procedure. There were no intraoperative complications in revising any of the failed resurfacing procedures. Results of revision of the failed component of a resurfacing procedure are comparable with those of conversion to a conventional hip arthroplasty. Thorough, prompt evaluation of hip pain in recipients of a hip resurfacing procedure is necessary for preservation of remaining bone stock. In comparison to revision of conventional hip arthroplasty, revision of failed resurfacing hip arthroplasty is technically easier and has a better prognosis in providing the patient with a pain-free, functional hip.

Computerized axial tomography-a method of localizing steinmann pin migration: a case report

Steinmann pins have long been used as a means of internally fixing acromioclavicular separations. A few reported cases have described the complications of pin migration.1-5 The purpose of this case report is to support computerized tomography for localizing foreign bodies in selected cases.

Augmented venous return: a model of left ventricular afterload reduction during the course of endotoxin shock

Utilizing a canine model of endotoxin shock (E coli, 4 mg/kg, B6:026) the major determinants of cardiac output (preload, afterload, contractility, and heart rate) were simultaneously followed for 5 hr in four study groups: Group I: time-matched controls, Group II: endotoxin shock, Group III: endotoxin shock and femoral-femoral A-V shunt, and Group IV: A-V shunt control. Groups II and III demonstrated an initial, abrupt increase in total peripheral resistance (TPR), coronary vascular resistance (CVR), and pulmonary vascular resistance (PVR), and a decrease in cardiac output (CO), coronary flow (CF) and heart rate (HR) and stroke work (P less than 0.05). Group II then demonstrated a decrease in TPR, CVR, PVR with an increase in CO and CF but systemic arterial pressure did not return to control values. At approximately 3 hr, Group II developed a progressive increase in TPR, CVR, and PVR, and a decrease in CO, CF, and SW. Heart rate did not change. In contrast, at 3 hr Group III demonstrated no significant increase in TPR, CVR, or PVR, a progressive increase of CO and CF, and preservation of SW. It is hypothesized that endotoxin shock is characterized by an initial phase characterized by an increase in resistance and decrease in flow that is not affected by an augmented venous return. However, in the intermediate and latter stages of shock, there is a progressive increase in resistance and decrease in flow, increasing impedance to left ventricular ejection that results in an imbalance between myocardial oxygen supply and demand, contributing to the observed myocardial failure. An augmented venous return, by decreasing resistance (afterload) and increasing venous return (preload) preserves cardiac output and myocardial function and thus serves as a model of left ventricular afterload reduction during the course of endotoxin shock.