Which imaging method is better for the differentiation of adenomyosis and uterine fibroids?

OBJECTIVE: The paper compares shear wave elastography (SWE), strain elastography (SE) and magnetic resonance imaging apparent diffusion coefficient (MRI ADC) values, to evaluate their efficacy for differentiating between adenomyosis (AM) and uterine fibroids (UF). METHODS: Patients who were scheduled for hysterectomy for AM or UFs, with a preliminary diagnosis, were additionally evaluated before surgery by transabdominal and transvaginal ultrasound elastography. SE of patients were evaluated by transvaginal ultrasound, and SWE of patients and control subjects were evaluated by transabdominal ultrasound. Then, the patients with a definitive histopathological diagnosis as AM or UFs were evaluated retrospectively and compared to the control group without myometrial pathology. In addition, MRI images of patients with UFs and AM were examined for ADC values. RESULTS: The results of 98 patients in the UF group, 37 patients in the AM group, and 40 volunteers with a healthy myometrium in the control group were compared. There were no statistically significant differences in age and body mass index between the groups (P > 0.05). Uterine size was significantly higher in the UF and AM group than the control group (P < 0.001). A statistically significant difference was found between strain ratio (mean), strain ratio (max), and ADC values between the UF and AM groups (P < 0.001 for all three). There was a statistically significant difference in elastography scores distribution between the groups (P < 0.001). There was a statistically significant difference between the UF and control (P < 0.001) and between the UF and AM (P < 0.001) groups in terms of SWE (kilopascal (kPa)) averages (P < 0.001). We found that none of these discrimination methods were statistically superior to each other in differentiating the UFs from the AM. CONCLUSION: In the differentiation of myometrial pathologies in gynecological imaging, both SE and SWE are cheaper, provide faster results, are non-invasive and easy to apply, and hence are as promising as the more expensive MRI ADC. Our study is the first to use both modalities of elastography and MRI ADC values together, compare these methods with each other and confirm the results pathologically.

Gadoxetate-enhanced abbreviated MRI is highly accurate for hepatocellular carcinoma screening.

OBJECTIVES: The primary objective was to compare the performance of 3 different abbreviated MRI (AMRI) sets extracted from a complete gadoxetate-enhanced MRI obtained for hepatocellular carcinoma (HCC) screening. Secondary objective was to perform a preliminary cost-effectiveness analysis, comparing each AMRI set to published ultrasound performance for HCC screening in the USA. METHODS: This retrospective study included 237 consecutive patients (M/F, 146/91; mean age, 58 years) with chronic liver disease who underwent a complete gadoxetate-enhanced MRI for HCC screening in 2017 in a single institution. Two radiologists independently reviewed 3 AMRI sets extracted from the complete exam: non-contrast (NC-AMRI: T2-weighted imaging (T2wi)+diffusion-weighted imaging (DWI)), dynamic-AMRI (Dyn-AMRI: T2wi+DWI+dynamic T1wi), and hepatobiliary phase AMRI (HBP-AMRI: T2wi+DWI+T1wi during the HBP). Each patient was classified as HCC-positive/HCC-negative based on the reference standard, which consisted in all available patient data. Diagnostic performance for HCC detection was compared between sets. Estimated set characteristics, including historical ultrasound data, were incorporated into a microsimulation model for cost-effectiveness analysis. RESULTS: The reference standard identified 13/237 patients with HCC (prevalence, 5.5%; mean size, 33.7 ± 30 mm). Pooled sensitivities were 61.5% for NC-AMRI (95% confidence intervals, 34.4-83%), 84.6% for Dyn-AMRI (60.8-95.1%), and 80.8% for HBP-AMRI (53.6-93.9%), without difference between sets (p range, 0.06-0.16). Pooled specificities were 95.5% (92.4-97.4%), 99.8% (98.4-100%), and 94.9% (91.6-96.9%), respectively, with a significant difference between Dyn-AMRI and the other sets (p < 0.01). All AMRI methods were effective compared with ultrasound, with life-year gain of 3-12 months against incremental costs of US$ < 12,000. CONCLUSIONS: NC-AMRI has limited sensitivity for HCC detection, while HBP-AMRI and Dyn-AMRI showed excellent sensitivity and specificity, the latter being slightly higher for Dyn-AMRI. Cost-effectiveness estimates showed that AMRI is effective compared with ultrasound. KEY POINTS: • Comparison of different abbreviated MRI (AMRI) sets reconstructed from a complete gadoxetate MRI demonstrated that non-contrast AMRI has low sensitivity (61.5%) compared with contrast-enhanced AMRI (80.8% for hepatobiliary phase AMRI and 84.6% for dynamic AMRI), with all sets having high specificity. • Non-contrast and hepatobiliary phase AMRI can be performed in less than 14 min (including set-up time), while dynamic AMRI can be performed in less than 17 min. • All AMRI sets were cost-effective for HCC screening in at-risk population in comparison with ultrasound.

Diffusion-weighted MRI at 3.0 T for detection of occult disease in the contralateral breast in women with newly diagnosed breast cancer.

PURPOSE: Diffusion-weighted magnetic resonance imaging (DW-MRI) offers unenhanced method to detect breast cancer without cost and safety concerns associated with dynamic contrast-enhanced (DCE) MRI. Our purpose was to evaluate the performance of DW-MRI at 3.0T in detection of clinically and mammographically occult contralateral breast cancer in patients with unilateral breast cancer. METHODS: Between 2017 and 2018, 1130 patients (mean age 53.3 years; range 26-84 years) with newly diagnosed unilateral breast cancer who underwent breast MRI and had no abnormalities on clinical and mammographic examinations of contralateral breast were included. Three experienced radiologists independently reviewed DW-MRI (b = 0 and 1000 s/mm2) and DCE-MRI and assigned a BI-RADS category. Using histopathology or 1-year clinical follow-up, performance measures of DW-MRI were compared with DCE-MRI. RESULTS: A total of 21 (1.9%, 21/1130) cancers were identified (12 ductal carcinoma in situ and 9 invasive ductal carcinoma; mean invasive tumor size, 8.0 mm) in the contralateral breast. Cancer detection rate of DW-MRI was 13-15 with mean of 14 per 1000 examinations (95% confidence interval [CI] 9-23 per 1000 examinations), which was lower than that of DCE-MRI (18-19 with mean of 18 per 1000 examinations, P = 0.01). A lower abnormal interpretation rate (14.0% versus 17.0%, respectively, P < 0.001) with higher specificity (87.3% versus 84.6%, respectively, P < 0.001) but lower sensitivity (77.8% versus 96.8%, respectively, P < 0.001) was noted for DW-MRI compared to DCE-MRI. CONCLUSIONS: DW-MRI at 3.0T has the potential as a cost-effective tool for evaluation of contralateral breast in women with newly diagnosed breast cancer.

Novel Cost Function Definition for Minimum-Cost Tractography in MR Diffusion Tensor Imaging.

Magnetic resonance imaging (MRI) is an established clinical technique that measures diffusion-weighted signals, applied primarily in brain studies. Diffusion tensor imaging (DTI) is a technique that uses the diffusion-weighted signals to obtain information about tissue connectivity, which recently started to become established in clinical use. The extraction of tracts (tractography) is an issue under active research. In this work we present an algorithm for recovering tracts, based on Dijkstra's minimum-cost path. A novel cost definition algorithm is presented that allows tract reconstruction, considering the tract's curvature, as well as its alignment with the diffusion vector field. The proposed cost function is able to adapt to linear, planar, and spherical diffusion. Thus, it can handle issues of fiber crossing, which pose considerable problems to tractography algorithms. A simple method for generating synthetic diffusion - weighted MR signals from known fibers - is also presented and utilized in this work. Results are shown for two (2D)- and three-dimensional (3D) synthetic data, as well as for a clinical MRI-DTI brain study.

Comparison of 18F-sodium fluoride PET/CT, 18F-fluorocholine PET/CT and diffusion-weighted MRI for the detection of bone metastases in recurrent prostate cancer: a cost-effectiveness analysis in France.

BACKGROUND: The diagnostic performance of 18F-sodium fluoride positron emission tomography/computed tomography (PET/CT) (NaF), 18F-fluorocholine PET/CT (FCH) and diffusion-weighted whole-body magnetic resonance imaging (DW-MRI) in detecting bone metastases in prostate cancer (PCa) patients with first biochemical recurrence (BCR) has already been published, but their cost-effectiveness in this indication have never been compared. METHODS: We performed trial-based and model-based economic evaluations. In the trial, PCa patients with first BCR after previous definitive treatment were prospectively included. Imaging readings were performed both on-site by local specialists and centrally by experts. The economic evaluation extrapolated the diagnostic performances of the imaging techniques using a combination of a decision tree and Markov model based on the natural history of PCa. The health states were non-metastatic and metastatic BCR, non-metastatic and metastatic castration-resistant prostate cancer and death. The state-transition probabilities and utilities associated with each health state were derived from the literature. Real costs were extracted from the National Cost Study of hospital costs and the social health insurance cost schedule. RESULTS: There was no significant difference in diagnostic performance among the 3 imaging modalities in detecting bone metastases. FCH was the most cost-effective imaging modality above a threshold incremental cost-effectiveness ratio of 3000€/QALY when imaging was interpreted by local specialists and 9000€/QALY when imaging was interpreted by experts. CONCLUSIONS: FCH had a better incremental effect on QALY, independent of imaging reading and should be preferred for detecting bone metastases in patients with biochemical recurrence of prostate cancer. TRIAL REGISTRATION: NCT01501630. Registered 29 December 2011.

Cost-comparison analysis of diffusion weighted magnetic resonance imaging (DWMRI) versus second look surgery for the detection of residual and recurrent cholesteatoma.

BACKGROUND: Cholesteatoma is a destructive, erosive growth of keratinizing squamous epithelium in the middle ear cleft. Following treatment with a canal wall-up (CWU) tympanomastoidectomy, surveillance of residual and recurrent disease has traditionally been achieved through a second look tympanotomy following the initial procedure. Historically, MRI sequences have been inadequate at differentiating between granulation tissue, inflammation, and cholesteatoma. Recent literature has shown diffusion-weighted magnetic resonance imaging (DWMRI) to be a viable alternative to second look surgery for the detection of residual or recurrent disease. The goal of the present study was to perform a cost analysis of DWIMRI versus second look surgery in the detection of residual or recurrent cholesteatoma following combined approach tympanomastoidectomy. METHODS: A probabilistic decision tree model was generated from a literature review to compare traditional second look surgery with DWMRI. Cost inputs were obtained from the Ontario Case Costing Initiative, the Ontario Health Insurance Plan (OHIP) schedule of benefits. Costs were reported in Canadian dollars and a payer perspective was adopted. A probabilistic sensitivity analysis was performed. RESULTS: According to the probabilistic sensitivity analysis, mean cost difference of traditional second look tympanotomy versus echo planar imaging (EPI) DWMRI was $180.27CAD, 95%CI [$177.32, $188,32] in favour of second-look tympanotomy. However, mean cost difference of traditional second look tympanotomy versus non-EPI DWMRI was $390.66CAD, 95%CI [$381.52, $399.80] in favour of non-EPI DWMRI. CONCLUSIONS: Diffusion-weighted MRI, specifically non-EPI sequences, are a viable cost-saving alternative to second-look tympanotomy in the setting of detecting residual or recurrent cholesteatoma.

Diagnostic Accuracy of a Rapid Biparametric MRI Protocol for Detection of Histologically Proven Prostate Cancer.

OBJECTIVE: To evaluate the performance of a rapid, low cost, noncontrast MRI examination as a secondary screening tool in detection of clinically significant prostate cancer. METHODS: In this prospective single institution study, 129 patients with elevated prostate-specific antigen levels or abnormal digital rectal examination findings underwent MRI with an abbreviated biparamatric MRI protocol consisting of high-resolution axial T2- and diffusion-weighted images. Index lesions were classified according to modified Prostate Imaging - Reporting and Data System (mPI-RADS) version 2.0. All patients underwent standard transrectal ultrasound-guided biopsy after MRI with the urologist being blinded to MRI results. Subsequently, all patients with suspicious lesions (mPI-RADS 3, 4, or 5) underwent cognitively guided targeted biopsy after discussion of MRI results with the urologist. Sensitivity and negative predictive value for identification of clinically significant prostate cancer (Gleason score 3+4 and above) were determined. RESULTS: Rapid biparametric MRI discovered 176 lesions identified in 129 patients. Rapid MRI detected clinically significant cancers with a sensitivity of 95.1% with a negative predictive value of 95.1% and positive predictive value of 53.2%, leading to a change in management in 10.8% of the patients. False negative rate of biparametric (bp) MRI was 4.7%. CONCLUSION: We found that a bp-MRI examination can detect clinically significant lesions and changed patient management in 10.8% of the patients. A rapid MRI protocol can be used as a useful secondary screening tool in men presenting with suspicion of prostate cancer.

Detection of recurrent hepatocellular carcinoma after surgical resection: Non-contrast liver MR imaging with diffusion-weighted imaging versus gadoxetic acid-enhanced MR imaging.

OBJECTIVE:: To compare the diagnostic performance of non-contrast liver MRI to whole MRI using gadoxetic acid for detection of recurrent hepatocellular carcinoma (HCC) after hepatectomy. METHODS:: This retrospective study analyzed 483 patients who underwent surveillance with liver MRI after hepatectomy for HCC (median time interval, 7.7 months). Non-contrast MRI set (T1- and T2 weighted and diffusion-weighted images) and whole MRI set (gadoxetic acid-enhanced and non-contrast MRI) were analyzed independently by two observers. Receiver operating characteristic analysis was used (with the observers' individual observations and consensus) to detect recurrent HCC. The accuracy, sensitivity, and specificity were calculated. RESULTS:: A total of 113 patients had 197 recurrent HCCs on first follow-up MRI. Although non-contrast MRI had fairly high sensitivity for recurrent HCC, there were significant differences in sensitivity (94.7% vs 99.1%, p = 0.025) and accuracy (97.5% vs 99.2%, p = 0.021) between the two image sets (per-patients base analysis). However, in patients followed for ≥1 year after surgery, the diagnostic performance of non-contrast MRI and whole MRI were not significantly different (p > 0.05). CONCLUSION:: Non-contrast MRI may serve as an alternative follow-up method which can potentially replace whole MRI at least in selected patients followed up ≥1 year after surgery who have relatively lower risk of HCC recurrence. ADVANCES IN KNOWLEDGE:: There is no consensus regarding the ideal imaging modality or follow-up interval after resection of HCC. Non-contrast MRI had comparable performance to that of gadoxetic acid-enhanced MRI in the detection of HCC recurrence during surveillance ≥1 year after surgery.

Safety and cost-effectiveness thrombolysis by diffusion-weighted imaging and fluid attenuated inversion recovery mismatch for wake-up stroke.

Wake-up stroke, defined as patients who wake up with stroke symptoms which were not present prior to falling asleep, accounted for 14%-25% of acute ischemic stroke. Due to the unknown time of symptom onset, wake-up stoke was not in including criteria of intravenous thrombolysis. Several large randomized stroke trials using diffusion-weighted imaging(DWI)and fluid attenuated inversion recovery(FLAIR)mismatch patient selection may identify a subset of patients with wake-up stroke that can safely and effectively benefit from intravenous thrombolysis. In addition, economic factor was another important limitation to generalize thrombolysis treatment. Fortunately, MRI-based thrombolysis was a cost-effective treatment for wake-up stroke compared to these patients with no thrombolysis.

Clinical Utility of Multiparametric Magnetic Resonance Imaging as the First-line Tool for Men with High Clinical Suspicion of Prostate Cancer.

BACKGROUND: Transrectal ultrasound-guided biopsy (TRUS-Bx) is recommended by the European Urology Association (EAU) as the first diagnostic modality for men at risk of prostate cancer (PCa). Current EAU guidelines reserve the use of multiparametric MRI to target or guide any repeat biopsy (mpMRI-Bx). It remains uncertain if TRUS-Bx is effective as a first strategy in terms of costs, diagnostic performance, time to diagnosis, and triage for individualised therapy. OBJECTIVE: To determine the diagnostic and treatment costs and the effectiveness of pathways incorporating mpMRI-Bx compared to TRUS-Bx in men at high risk of PCa. DESIGN, SETTING, AND PARTICIPANTS: A cost and time analysis was performed using data from a randomised single-centre study of 1140 patients (prostate-specific antigen >4ng/ml) divided into two groups: 570 patients underwent an initial TRUS-Bx and 570 underwent 3-T mpMRI-Bx. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Budget analyses were used to compare the diagnostic strategies using reimbursement data from the Italian National Health Security system. Analyses of reimbursable diagnostic and treatment costs were undertaken separately. Histologic outcomes, pathway diagnostic accuracy, therapy choices, and time to diagnosis were compared. RESULTS AND LIMITATIONS: The cumulative diagnosis costs were 14.6% greater for the mpMRI-Bx pathway than for the TRUS strategy, and 5.2-6.0% higher for therapy. Diagnostic costs were €228 946 for mpMRI-Bx and €199 750 for TRUS-Bx, and the corresponding therapy costs were €1 912 000 and €1 802 800. The mpMRI-Bx strategy was highly effective in excluding clinically significant disease (Gleason ≥7; sensitivity and negative predictive value both 100%, 95% confidence interval 98-100%). The time to diagnosis was significantly shorter for the mpMRI-Bx (median 4.0 mo interquartile range [IQR] 3-6) than for the TRUS-Bx strategy (median 6 mo, IQR 4-12; p<0.001). Limitations include the lack of data on costs associated with treatment-related complications and follow-up data. CONCLUSIONS: The mpMRI-Bx strategy is effective for diagnosing patients with a clinical suspicion of PCa and provides more accurate diagnosis, with combined diagnosis and therapy costs only moderately higher than for the standard strategy. PATIENT SUMMARY: It is a matter of debate whether a diagnostic pathway that incorporates multiparametric magnetic resonance imaging (MRI) as the first-line test before performing any type of biopsy in men suspected of having prostate cancer (PCa) is cost-effective. Our analysis of the costs for men suspected of harbouring PCa revealed higher diagnostic costs for the MRI approach, with the benefits of greater diagnostic accuracy. Moreover, the combined diagnostic and treatment costs are only modestly higher whenever the same treatment for all patients is considered.

Economic Benefits and Diagnostic Quality of Diffusion-Weighted Magnetic Resonance Imaging for Primary Lung Cancer.

This paper focuses on the latest research of diffusion-weighted magnetic resonance imaging (DWI), and deals with economic benefits, diagnostic benefits, and prospects of DWI for lung cancer. The medical cost of a magnetic resonance imaging (MRI) is 81%-84% cheaper than that of 18-fluoro-2-deoxy-glucose positron emission tomography/computed tomography (FDG-PET/CT). DWI is reported to be useful for differential diagnosis of malignancy or benignity for neoplasm in various organs. Diagnostic efficacy by DWI for pulmonary nodules and masses and the evaluation of N factor and M factor in lung cancer are equivalent to or more than that of FDG-PET/CT. The diagnostic capability of whole-body DWI (WB-DWI) for the staging of clinically operable lung cancers is equivalent to that of FDG-PET/CT and brain MRI, and WB-DWI is now becoming a more main stream procedure. Although the diagnostic performance of DWI for lung cancer may be equivalent to that of FDG-PET/CT, prospective randomized controlled trial for comparison of diagnostic efficacy between FDG-PET/CT and DWI for lung cancer is necessary for an accurate comparison. DWI may have an advantage in the aspect of the cost and diagnostic efficacy in lung cancer management.

Cost-effectiveness of response evaluation after chemoradiation in patients with advanced oropharyngeal cancer using 18F-FDG-PET-CT and/or diffusion-weighted MRI.

BACKGROUND: Considerable variation exists in diagnostic tests used for local response evaluation after chemoradiation in patients with advanced oropharyngeal cancer. The yield of invasive examination under general anesthesia (EUA) with biopsies in all patients is low and it may induce substantial morbidity. We explored four response evaluation strategies to detect local residual disease in terms of diagnostic accuracy and cost-effectiveness. METHODS: We built a decision-analytic model using trial data of forty-six patients and scientific literature. We estimated for four strategies the proportion of correct diagnoses, costs concerning diagnostic instruments and the proportion of unnecessary EUA indications. Besides a reference strategy, i.e. EUA for all patients, we considered three imaging strategies consisting of 18FDG-PET-CT, diffusion-weighted MRI (DW-MRI), or both 18FDG-PET-CT and DW-MRI followed by EUA after a positive test. The impact of uncertainty was assessed in sensitivity analyses. RESULTS: The EUA strategy led to 96% correct diagnoses. Expected costs were €468 per patient whereas 89% of EUA indications were unnecessary. The DW-MRI strategy was the least costly strategy, but also led to the lowest proportion of correct diagnoses, i.e. 93%. The PET-CT strategy and combined imaging strategy were dominated by the EUA strategy due to respectively a smaller or equal proportion of correct diagnoses, at higher costs. However, the combination of PET-CT and DW-MRI had the highest sensitivity. All imaging strategies considerably reduced (unnecessary) EUA indications and its associated burden compared to the EUA strategy. CONCLUSIONS: Because the combined PET-CT and DW-MRI strategy costs only an additional €927 per patient, it is preferred over immediate EUA since it reaches the same diagnostic accuracy in detecting local residual disease while leading to substantially less unnecessary EUA indications. However, if healthcare resources are limited, DW-MRI is the strategy of choice because of lower costs while still providing a large reduction in unnecessary EUA indications.

Technical Note: A safe, cheap, and easy-to-use isotropic diffusion MRI phantom for clinical and multicenter studies.

PURPOSE: Since Diffusion Weighted Imaging (DWI) data acquisition and processing are not standardized, substantial differences in DWI derived measures such as Apparent Diffusion Coefficient (ADC) may arise which are related to the acquisition or MRI processing method, but not to the sample under study. Quality assurance using a standardized test object, or phantom, is a key factor in standardizing DWI across scanners. METHODS: Current diffusion phantoms are either complex to use, not available in larger quantities, contain substances unwanted in a clinical environment, or are expensive. A diffusion phantom based on a polyvinylpyrrolidone (PVP) solution, together with a phantom holder, is presented and compared to existing diffusion phantoms for use in clinical DWI scans. An ADC vs. temperature calibration curve was obtained. RESULTS: ADC of the phantom (808 to 857 ± 0.2 mm2 /s) is in the same range as ADC values found in brain tissue. ADC measurements are highly reproducible across time with an intra-class correlation coefficient of > 0.8. ADC as function of temperature (in Kelvin) can be estimated as ADCm(T)=[exp(-7.09)·exp-2903.81T-1293.55] with a total uncertainty (95% confidence limit) of ± 1.7%. CONCLUSION: We present an isotropic diffusion MRI phantom, together with its temperature calibration curve, that is easy-to-use in a clinical environment, cost-effective, reproducible to produce, and that contains no harmful substances.

Health economic aspects of evaluation with diffusion weighted MR and MR colonography compared to standard evaluation with colonoscopy and CT before rectal cancer surgery.

Background Colorectal cancer is a frequent type of cancer, and with the risk of synchronous disease, the need for a complete staging leads to an extensive and costly preoperative diagnostic evaluation. Previously we described a total preoperative evaluation using magnetic resonance (MR) colonography and diffusion-weighted MR of the liver. Purpose To compare the economic aspects of this modality with the standard evaluation in an analysis of the different cost drivers. Material and Methods Based on the results from previous studies, two calculations were performed, a theoretical cost calculation and a practical cost calculation. The cost drivers utilized are an average cost based on the cost of all procedures and diagnostic modalities performed in hospitalized patients (DRG) and outpatients (DAGS [Danish outpatient grouping system]) in Denmark. Results The total cost for a full colorectal evaluation and computed tomography (CT) scan of the thorax/abdomen was less for the new modality group in all theoretical models proposed; €225 using model A, €322 using model B, and €383 using model C. Using results from previous studies, the actual difference and the potential difference in cost between the two preoperative diagnostic modalities per patient were €312 and €712, respectively. Conclusion This cost analysis shows the cost effectiveness of the new modality as the future standard preoperative diagnostic work-up by reducing total cost and by having a higher sensitivity and completion rate.

Should DWI MRI be the primary screening test for stroke?

Patients presenting with focal neurological symptoms may suffer from ischemic stroke, intracerebral hemorrhage, or stroke mimics. Such patients are usually screened with a noncontrast-enhanced computed tomography to rule out hemorrhage and to detect early signs of ischemia. However, the sensitivity of noncontrast-enhanced computed tomography for acute stroke is far inferior to that of diffusion-weighted magnetic resonance imaging and the latter is also very sensitive for identifying acute intracerebral hemorrhage. Most centers perform a magnetic resonance imaging stroke protocol that takes long to accomplish and may therefore delay therapy. Herein, we propose that a short diffusion-weighted imaging-only magnetic resonance imaging protocol can effectively differentiate ischemic stroke from intracerebral hemorrhage and stroke mimics and could therefore be used as the first line screening test for stroke. Adopting such a screening strategy will result in increased diagnostic accuracy and avoidance of unnecessary treatment of stroke mimics with thrombolysis but may come at the increased cost of performing a magnetic resonance imaging at the emergency department. Whether such a strategy will be cost effective or not remains to be tested in future studies.

An assessment of the cost-effectiveness of magnetic resonance, including diffusion-weighted imaging, in patients with transient ischaemic attack and minor stroke: a systematic review, meta-analysis and economic evaluation.

BACKGROUND: Patients with transient ischaemic attack (TIA) or minor stroke need rapid treatment of risk factors to prevent recurrent stroke. ABCD2 score or magnetic resonance diffusion-weighted brain imaging (MR DWI) may help assessment and treatment. OBJECTIVES: Is MR with DWI cost-effective in stroke prevention compared with computed tomography (CT) brain scanning in all patients, in specific subgroups or as 'one-stop' brain-carotid imaging? What is the current UK availability of services for stroke prevention? DATA SOURCES: Published literature; stroke registries, audit and randomised clinical trials; national databases; survey of UK clinical and imaging services for stroke; expert opinion. REVIEW METHODS: Systematic reviews and meta-analyses of published/unpublished data. Decision-analytic model of stroke prevention including on a 20-year time horizon including nine representative imaging scenarios. RESULTS: The pooled recurrent stroke rate after TIA (53 studies, 30,558 patients) is 5.2% [95% confidence interval (CI) 3.9% to 5.9%] by 7 days, and 6.7% (5.2% to 8.7%) at 90 days. ABCD2 score does not identify patients with key stroke causes or identify mimics: 66% of specialist-diagnosed true TIAs and 35-41% of mimics had an ABCD2 score of ≥ 4; 20% of true TIAs with ABCD2 score of < 4 had key risk factors. MR DWI (45 studies, 9078 patients) showed an acute ischaemic lesion in 34.3% (95% CI 30.5% to 38.4%) of TIA, 69% of minor stroke patients, i.e. two-thirds of TIA patients are DWI negative. TIA mimics (16 studies, 14,542 patients) make up 40-45% of patients attending clinics. UK survey (45% response) showed most secondary prevention started prior to clinic, 85% of primary brain imaging was same-day CT; 51-54% of patients had MR, mostly additional to CT, on average 1 week later; 55% omitted blood-sensitive MR sequences. Compared with 'CT scan all patients' MR was more expensive and no more cost-effective, except for patients presenting at > 1 week after symptoms to diagnose haemorrhage; strategies that triaged patients with low ABCD2 scores for slow investigation or treated DWI-negative patients as non-TIA/minor stroke prevented fewer strokes and increased costs. 'One-stop' CT/MR angiographic-plus-brain imaging was not cost-effective. LIMITATIONS: Data on sensitivity/specificity of MR in TIA/minor stroke, stroke costs, prognosis of TIA mimics and accuracy of ABCD2 score by non-specialists are sparse or absent; all analysis had substantial heterogeneity. CONCLUSIONS: Magnetic resonance with DWI is not cost-effective for secondary stroke prevention. MR was most helpful in patients presenting at > 1 week after symptoms if blood-sensitive sequences were used. ABCD2 score is unlikely to facilitate patient triage by non-stroke specialists. Rapid specialist assessment, CT brain scanning and identification of serious underlying stroke causes is the most cost-effective stroke prevention strategy. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

The diagnostic accuracy and cost-effectiveness of magnetic resonance spectroscopy and enhanced magnetic resonance imaging techniques in aiding the localisation of prostate abnormalities for biopsy: a systematic review and economic evaluation.

BACKGROUND: In the UK, prostate cancer (PC) is the most common cancer in men. A diagnosis can be confirmed only following a prostate biopsy. Many men find themselves with an elevated prostate-specific antigen (PSA) level and a negative biopsy. The best way to manage these men remains uncertain. OBJECTIVES: To assess the diagnostic accuracy of magnetic resonance spectroscopy (MRS) and enhanced magnetic resonance imaging (MRI) techniques [dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DW-MRI)] and the clinical effectiveness and cost-effectiveness of strategies involving their use in aiding the localisation of prostate abnormalities for biopsy in patients with prior negative biopsy who remain clinically suspicious for harbouring malignancy. DATA SOURCES: Databases searched--MEDLINE (1946 to March 2012), MEDLINE In-Process & Other Non-Indexed Citations (March 2012), EMBASE (1980 to March 2012), Bioscience Information Service (BIOSIS; 1995 to March 2012), Science Citation Index (SCI; 1995 to March 2012), The Cochrane Library (Issue 3 2012), Database of Abstracts of Reviews of Effects (DARE; March 2012), Medion (March 2012) and Health Technology Assessment database (March 2012). REVIEW METHODS: Types of studies: direct studies/randomised controlled trials reporting diagnostic outcomes. INDEX TESTS: MRS, DCE-MRI and DW-MRI. Comparators: T2-weighted magnetic resonance imaging (T2-MRI), transrectal ultrasound-guided biopsy (TRUS/Bx). Reference standard: histopathological assessment of biopsied tissue. A Markov model was developed to assess the cost-effectiveness of alternative MRS/MRI sequences to direct TRUS-guided biopsies compared with systematic extended-cores TRUS-guided biopsies. A health service provider perspective was adopted and the recommended 3.5% discount rate was applied to costs and outcomes. RESULTS: A total of 51 studies were included. In pooled estimates, sensitivity [95% confidence interval (CI)] was highest for MRS (92%; 95% CI 86% to 95%). Specificity was highest for TRUS (imaging test) (81%; 95% CI 77% to 85%). Lifetime costs ranged from £3895 using systematic TRUS-guided biopsies to £4056 using findings on T2-MRI or DCE-MRI to direct biopsies (60-year-old cohort, cancer prevalence 24%). The base-case incremental cost-effectiveness ratio for T2-MRI was <£30,000 per QALY (all cohorts). Probabilistic sensitivity analysis showed high uncertainty surrounding the incremental cost-effectiveness of T2-MRI in moderate prevalence cohorts. The cost-effectiveness of MRS compared with T2-MRI and TRUS was sensitive to several key parameters. LIMITATIONS: Non-English-language studies were excluded. Few studies reported DCE-MRI/DW-MRI. The modelling was hampered by limited data on the relative diagnostic accuracy of alternative strategies, the natural history of cancer detected at repeat biopsy, and the impact of diagnosis and treatment on disease progression and health-related quality of life. CONCLUSIONS: MRS had higher sensitivity and specificity than T2-MRI. Relative cost-effectiveness of alternative strategies was sensitive to key parameters/assumptions. Under certain circumstances T2-MRI may be cost-effective compared with systematic TRUS. If MRS and DW-MRI can be shown to have high sensitivity for detecting moderate/high-risk cancer, while negating patients with no cancer/low-risk disease to undergo biopsy, their use could represent a cost-effective approach to diagnosis. However, owing to the relative paucity of reliable data, further studies are required. In particular, prospective studies are required in men with suspected PC and elevated PSA levels but previously negative biopsy comparing the utility of the individual and combined components of a multiparametric magnetic resonance (MR) approach (MRS, DCE-MRI and DW-MRI) with both a MR-guided/-directed biopsy session and an extended 14-core TRUS-guided biopsy scheme against a reference standard of histopathological assessment of biopsied tissue obtained via saturation biopsy, template biopsy or prostatectomy specimens. STUDY REGISTRATION: PROSPERO number CRD42011001376. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

[EU-funded treatment study: WAKE-UP: a randomized, placebo-controlled MRI-based trial of thrombolysis in wake-up stroke]. / EU-geförderte Therapiestudie WAKE-UP : Eine randomisierte, placebokontrollierte, MRT-basierte Thrombolysestudie bei "wake-up stroke"

Patients waking up with stroke symptoms are generally excluded from intravenous thrombolysis. It was shown that magnetic resonance imaging (MRI) can identify patients within the time window for thrombolysis (≤ 4.5 h from symptom onset) by a mismatch between the acute ischemic lesion visible on diffusion-weighted imaging (DWI) but not visible on fluid-attenuated inversion recovery (FLAIR) imaging. The WAKE-UP trial is an investigator initiated, European, randomized, double-blind, placebo-controlled trial designed to test efficacy and safety of MRI-based thrombolysis with alteplase (tPA) in stroke patients with unknown time of symptom onset, e.g. due to symptom recognition on awakening. A total of 800 patients showing MRI findings of a DWI-FLAIR-mismatch will be randomized to either tPA or placebo. The primary efficacy endpoint will be favourable outcome defined by a modified Rankin scale score 0-1 at day 90. The primary safety outcome measures will be mortality and death or dependency defined by modified Rankin scale score 4-6 at 90 days. If positive the WAKE-UP trial is expected to change clinical practice and to make effective and safe treatment available for a large group of acute stroke patients currently excluded from specific acute treatment.

[Whole-body diffusion-weighted imaging in oncology: technical aspects and practical relevance]. / Ganzkörperdiffusionsbildgebung in der Onkologie: Technische Aspekte und praktischer Stellenwert.

This review illustrates the relevance of whole-body diffusion-weighted imaging (WB-DWI) in the field of oncological imaging. WB-DWI is an alternative method to positron-emission tomography/computed tomography (PET/CT) due to the lack of radiation and lower examination costs. Technical aspects of WB-DWI and the current role of the method in cancer imaging regarding practical requirements in oncology are presented.

Statistical analysis of minimum cost path based structural brain connectivity.

Diffusion MRI can be used to study the structural connectivity within the brain. Brain connectivity is often represented by a binary network whose topology can be studied using graph theory. We present a framework for the construction of weighted structural brain networks, containing information about connectivity, which can be effectively analyzed using statistical methods. Network nodes are defined by segmentation of subcortical structures and by cortical parcellation. Connectivity is established using a minimum cost path (mcp) method with an anisotropic local cost function based directly on diffusion weighted images. We refer to this framework as Statistical Analysis of Minimum cost path based Structural Connectivity (SAMSCo) and the weighted structural connectivity networks as mcp-networks. In a proof of principle study we investigated the information contained in mcp-networks by predicting subject age based on the mcp-networks of a group of 974 middle-aged and elderly subjects. Using SAMSCo, age was predicted with an average error of 3.7 years. This was significantly better than predictions based on fractional anisotropy or mean diffusivity averaged over the whole white matter or over the corpus callosum, which showed average prediction errors of at least 4.8 years. Additionally, we classified subjects, based on the mcp-networks, into groups with low and high white matter lesion load, while correcting for age, sex and white matter atrophy. The SAMSCo classification outperformed the classification based on the diffusion measures with a classification accuracy of 76.0% versus 63.2%. We also performed a classification in groups with mild and severe atrophy, correcting for age, sex and white matter lesion load. In this case, mcp-networks and diffusion measures yielded similar classification accuracies of 68.3% and 67.8% respectively. The SAMSCo prediction and classification experiments indicate that the mcp-networks contain information regarding age, white matter lesion load and white matter atrophy, and that in case of age and white matter lesion load the mcp-network based models outperformed the predictions based on diffusion measures.