The diagnostic and therapeutic impact of MRI: an observational multi-centre study

Investigating hybrid nanoparticles for drug delivery in multi-stenosed catheterized arteries under magnetic field effects

This groundbreaking study pioneers the exploration of the therapeutic implications of a constant magnetic field simultaneously with hybrid nanoparticles on blood flow within a tapered artery, characterized by multiple stenosis along its exterior walls and a central thrombus, employing three-dimensional bio-fluid simulations. In addition, a magnetized catheter is inserted into the thrombus to increase the therapeutic potential of this novel method. The flow condition under consideration has applications in targeted medication distribution, improved medical device design, and improved diagnostics, as well as in advancing healthcare and biomedical engineering. Our investigation primarily aims to optimize blood flow efficiency, encompassing key parameters like pressure, velocity, and heat fluctuations influenced by diverse geometric constraints within the stenotic artery. Precise solutions are obtained through the finite element method (FEM) coupled with advanced bio-fluid dynamics (BFD) software. Hybrid nanoparticles and magnetic fields impacted pressure and velocity, notably reducing pressure within the stenosis. Convective heat flux remained uniform, while temperature profiles showed consistent inlet rise and gradual decline with transient variations. This approach promotes fluid flow, and convection within stenosed arteries, enhances heat transport, evacuates heat from stenotic regions, and improves heat dispersion to surrounding tissues. These findings hold promise for targeted therapies, benefiting patients with vascular disorders, and advancing our understanding of complex bio-fluid dynamics.

Prevalence of Brain Magnetic Resonance Imaging Diagnoses and Correlation With Signalment and Presenting Complaint in Dogs

Since magnetic resonance imaging (MRI) was introduced, it has become increasingly available and technologically improved. Studies have documented the prevalence of specific pathologies, however no previous veterinary studies have investigated the prevalence and distribution of pathology across all MRIs performed at a single institution. The present study aimed to evaluate the prevalence of MRI-diagnosed brain lesions and correlate these to patient signalment and presenting complaint. Archived MRI brain scans from 805 dogs were reviewed retrospectively. One board-certified veterinary radiologist at the institution retrospectively evaluated all reports to determine the most clinically pertinent imaging diagnosis for each case. Breed, age, and presenting complaint were obtained from the medical record for each patient. The most common imaging diagnoses across all dogs reviewed were no significant findings (35.16%), asymmetric encephalopathy or meningoencephalopathy (19.75%), and extra-axial intracranial mass (11.18%). Age of dogs differed by diagnosis (p <0.0001), with the median age of dogs diagnosed with a brain mass being greater than that of dogs with no significant findings and dogs with asymmetric encephalopathy or meningoencephalopathy (both p <0.0083). In dogs presenting with seizures, the odds of a brain mass increased with each additional year of age [p <0.0001, odds ratio 1.26 (95% CI 1.16–1.37)], whereas the odds of no significant finding [p <0.0001, OR 0.87 (0.82–0.93)] decreased. Our findings provide overview information on the types of disease observed in the clinical population and allow us to detect correlations between imaging diagnoses, presenting complaints, and signalment.

Magnetic Resonance Imaging Safety in Patients with Cardiac Implantable Electronic Devices

High strength magnetic and electric fields used in magnetic resonance imaging (MRI) render images with unmatched soft tissue contrast. These imaging attributes have made MRI an increasingly preferred diagnostic tool in many medical conditions. Initially there was substantial concern regarding the safety of performing these imaging studies in patients with cardiac implantable electronic devices (CIEDs), which have the potential to be affected by the intense electric and magnetic fields of the MRI. More recently, there has been increasing evidence that MRI can be performed safely in patients with devices that have not been specifically labelled by regulatory agencies for use in an MRI environment (MRI nonconditional devices), which has allowed the Centers for Medicare and Medicaid Services (CMS) to start providing reimbursement for MRIs of patients with MRI nonconditional devices. For CMS to reimburse scans, a rigorous protocol must be followed, which recognizes that there are still potential adverse effects that can be mitigated by appropriate procedures. In this review we will survey the initial experiences and efforts to understand the magnitude of risk for device malfunction and harm, as well as current efforts to minimize the potential risks of MRI effects on devices and leads (heating, device movement, lead dislodgement, and device malfunction, the latter including inhibition of pacing and generation of arrhythmias).

MRI Features of the Vomeronasal Organ in Dogs (Canis Familiaris)

According to current knowledge, the vomeronasal organ (VNO, Jacobson's organ) is the structure responsible for semiochemical signal detection. In dogs and other mammals, it is located close to the vomer and palatine processes of the incisive and maxillary bones. Although there are reports describing the anatomy and histology of this structure, there are limited available reports assessing this organ in live individuals and no direct visualization reports in dogs. The aim of this study was 2-fold: (1) preparation and optimization of a protocol for magnetic resonance imaging (MRI) examination of the VNO in a cadaver study with precise visualization and localization, and (2) characterization of the physiological VNO image features in MRI of live dogs. The first part of the study was performed on 10 beagle cadavers, the second on 8 live beagle dogs. For the VNO visualization, a 1.5T MRI (Philips® Ingenia) scanner and 20-channel digital head-neck spine coil were used (Philips®, Holland). The cadaver study allowed confirmation of the organ's location by the topical application of an MRI contrast agent (gadolinium) via the external entrance of the VNO canal. Accurate delineation of the VNO was obtained using a high resolution submillimeter three-dimensional T1-fast field echo (FFE) 3D sequence. Imaging of the VNO in 8 living dogs allowed the description of the morphological MRI features and direct evaluation of its shape and size. The results obtained demonstrate the ability to visualize the VNO in vivo and to evaluate its structure in dogs.

Quantitative sodium MR imaging: A review of its evolving role in medicine

Sodium magnetic resonance (MR) imaging in humans has promised metabolic information that can improve medical management in important diseases. This technology has yet to find a role in clinical practice, lagging proton MR imaging by decades. This review covers the literature that demonstrates that this delay is explained by initial challenges of low sensitivity at low magnetic fields and the limited performance of gradients and electronics available in the 1980s. These constraints were removed by the introduction of 3T and now ultrahigh (≥7T) magnetic field scanners with superior gradients and electronics for proton MR imaging. New projection pulse sequence designs have greatly improved sodium acquisition efficiency. The increased field strength has provided the expected increased sensitivity to achieve resolutions acceptable for metabolic interpretation even in small target tissues. Consistency of quantification of the sodium MR image to provide metabolic parametric maps has been demonstrated by several different pulse sequences and calibration procedures. The vital roles of sodium ion in membrane transport and the extracellular matrix will be reviewed to indicate the broad opportunities that now exist for clinical sodium MR imaging. The final challenge is for the technology to be supplied on clinical ≥3T scanners.

Comparison between multi-slice spiral CT and magnetic resonance imaging in the diagnosis of peritoneal metastasis in primary ovarian carcinoma

The advent of disease evaluation by means of multi-slice spiral computed tomography (MSCT) and magnetic resonance imaging (MRI) represents a continually emerging role in the evaluation of various diseases; however, its role is yet to be adequately defined. Thus, the aim of the study was to compare the diagnostic value of MSCT and MRI in the diagnosis of peritoneal metastasis in primary ovarian carcinoma. Between January 2013 and December 2015, MSCT or MRI data were collected from 42 patients who had been previously diagnosed with peritoneal metastasis of ovarian carcinoma at the First Affiliated Hospital of Kunming Medical University. The tumor location, size, edge, and shape were all evaluated independently by three qualified imaging physicians using a double-blind method to confirm whether the patients were indeed suffering from peritoneal metastasis, as well as to rank the metastatic lesions recorded on a five-point scale. It was hypothesized that MRI and MSCT were comparable in the evaluation of ovarian carcinoma. Therefore, a receiver operating characteristics (ROC) curve was used to analyze the results and also to directly compare the respective diagnostic values of MSCT and MRI. In total, 165 metastatic lesions were confirmed by means of surgical operation. MSCT revealed 131 metastatic lesions, while MRI confirmed 154 metastatic lesions. The metastatic sites were primarily located on the subphrenic, epiploon, and gastrocolic ligaments and were further confirmed by either MRI or CT. In regard to MSCT, the most common site of underdiagnoses was in the vicinity of the uterus-rectum-fossa. MRI displayed a high detection rate in every site. The omission diagnostic rate of MSCT and MRI were 20.61% and 6.67%, respectively, while the accuracy rates were 79.39% and 93.33%, respectively. The obtained results revealed that the MSCT value of area under the ROC curve was smaller than that for MRI. Our findings provided evidence asserting that MRI, in comparison to MSCT, was more accurate in diagnosing peritoneal metastasis in patients with ovarian carcinoma.

Traumatic brain injury: classification, models, and markers

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Due to its high incidence rate and often long-term sequelae, TBI contributes significantly to increasing costs of health care expenditures annually. Unfortunately, advances in the field have been stifled by patient and injury heterogeneity that pose a major challenge in TBI prevention, diagnosis, and treatment. In this review, we briefly discuss the causes of TBI, followed by its prevalence, classification, and pathophysiology. The current imaging detection methods and animal models used to study brain injury are examined. We discuss the potential use of molecular markers in detecting and monitoring the progression of TBI, with particular emphasis on microRNAs as a novel class of molecular modulators of injury and its repair in the neural tissue.

Self-Assembled, Biodegradable Magnetic Resonance Imaging Agents: Organic Radical-Functionalized Diblock Copolymers

We report the design, synthesis, and evaluation of biodegradable amphiphilic poly(ethylene glycol)-b-polycarbonate-based diblock copolymers containing pendant persistent organic radicals (e.g., PROXYL). These paramagnetic radical-functionalized polymers self-assemble into micellar nanoparticles in aqueous media, which preferentially accumulate in tumor tissue via the enhanced permeability and retention (EPR) effect. Through T₁ relaxation NMR studies, as well as magnetic resonance imaging (MRI) studies on mice, we show that these nanomaterials are effective as metal-free, biodegradable MRI contrast agents. We also demonstrate anticancer drugs can be readily loaded into the nanoparticles, conferring therapeutic delivery properties in addition to their imaging properties making these materials potential theranostic agents in the treatment of cancer.

Cerebral magnetic resonance imaging in quiescent Crohn’s disease patients with fatigue

AIM

To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI).

METHODS

Multiple MRI techniques were used to assess cerebral changes in 20 quiescent CD patients with fatigue (defined with at least 6 points out of an 11-point numeric rating scale compared with 17 healthy age and gender matched controls without fatigue. Furthermore, mental status was assessed by cognitive functioning, based on the neuropsychological inventory including the different domains global cognitive functioning, memory and executive functioning and in addition mood and quality of life scores. Cognitive functioning and mood status were correlated with MRI findings in the both study groups.

RESULTS

Reduced glutamate + glutamine (Glx = Glu + Gln) concentrations (P = 0.02) and ratios to total creatine (P = 0.02) were found in CD patients compared with controls. Significant increased Cerebral Blood Flow (P = 0.05) was found in CD patients (53.08 ± 6.14 mL/100 g/min) compared with controls (47.60 ± 8.62 mL/100 g/min). CD patients encountered significantly more depressive symptoms (P < 0.001). Cognitive functioning scores related to memory (P = 0.007) and executive functioning (P = 0.02) were lower in CD patients and both scores showed correlation with depression and anxiety. No correlation was found subcortical volumes between CD patients and controls in the T₁-weighted analysis. In addition, no correlation was found between mental status and MRI findings.

CONCLUSION

This work shows evidence for perfusion, neurochemical and mental differences in the brain of CD patients with fatigue compared with healthy controls.

Polyurethane based organic macromolecular contrast agents (PU-ORCAs) for magnetic resonance imaging

Combination of its convenience for non-invasive application and high spatial resolution make Magnetic Resonance Imaging (MRI) one of the leading imaging modalities.

Analytical and simulation results of a triple micro whispering gallery mode probe system for a 3D blood flow rate sensor

The whispering gallery mode (WGM) is generated by light propagating within a nonlinear micro-ring resonator, which is modeled and made by an InGaAsP/InP material, and called a Panda ring resonator. An imaging probe can also be formed by the micro-conjugate mirror function for the appropriate Panda ring parameter control. The 3D WGM probe can be generated and used for a 3D sensor head and imaging probe. The analytical details and simulation results are given, in which the simulation results are obtained by using the MATLAB and Optiwave programs. From the obtained results, such a design system can be configured to be a thin-film sensor system that can contact the sample surface for the required measurements The outputs of the system are in the form of a WGM beam, in which the 3D WGM probe is also available with the micro-conjugate mirror function. Such a 3D probe can penetrate into the blood vessel and content, from which the time delay among those probes can be detected and measured, and where finally the blood flow rate can be calculated and the blood content 3D image can also be seen and used for medical diagnosis. The tested results have shown that the blood flow rate of 0.72-1.11  μs^-1, with the blood density of 1060  kgm^-3, can be obtained.

Magnetic resonance microimaging of a swine infarcted heart: Performing cardiac virtual histologies

The aim of this study is to develop a computer-aided intuitive software tool based on MATLAB to reproduce the functions of a virtual histology over Magnetic Resonance (MR) microimages of small samples of swine's infarcted hearts. The basic characterization consists of selecting regions of interest (ROIs) of that MR microimage and extracting the most important information of these regions. The software tool will implement intuitive and sophisticated tools that allow the user to define ROIs on the different types of images provided by the MR scanner. The final purpose of this tool will be to analyze the acquired data in order to characterize some aspects of the later possible events after a myocardial infarction in swine's hearts and expand the study to human cases.

Novel Magnetic Resonance Imaging Techniques in Brain Tumors

Magnetic resonance imaging is a powerful, noninvasive imaging technique with exquisite sensitivity to soft tissue composition. Magnetic resonance imaging is primary tool for brain tumor diagnosis, evaluation of drug response assessment, and clinical monitoring of the patient during the course of their disease. The flexibility of magnetic resonance imaging pulse sequence design allows for a variety of image contrasts to be acquired, including information about magnetic resonance-specific tissue characteristics, molecular dynamics, microstructural organization, vascular composition, and biochemical status. The current review highlights recent advancements and novel approaches in MR characterization of brain tumors.

Integrin αvβ3–Targeted Dynamic Contrast–Enhanced Magnetic Resonance Imaging Using a Gadolinium-Loaded Polyethylene Gycol–Dendrimer–Cyclic RGD Conjugate to Evaluate Tumor Angiogenesis and to Assess Early Antiangiogenic Treatment Response in a Mouse Xenograft Tumor Model

The purpose of this study was to validate an integrin αvβ3–targeted magnetic resonance contrast agent, PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2, for its ability to detect tumor angiogenesis and assess early response to antiangiogenic therapy using dynamic contrast–enhanced (DCE) magnetic resonance imaging (MRI). Integrin αvβ3–positive U87 cells and control groups were incubated with fluorescein-labeled cRGD-conjugated dendrimer, and the cellular attachment of the dendrimer was observed. DCE MRI was performed on mice bearing KB xenograft tumors using either PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2 or PEG-G3-(Gd-DTPA)6-(cRAD-DTPA)2. DCE MRI was also performed 2 hours after anti–integrin αvβ3 monoclonal antibody treatment and after bevacizumab treatment on days 3 and 6t. Using DCE MRI, the 30-minute contrast washout percentage was significantly lower in the cRGD-conjugate injection groups. The enhancement patterns were different between the two contrast injection groups. In the antiangiogenic therapy groups, a rapid increase in 30-minute contrast washout percentage was observed in both the LM609 and bevacizumab treatment groups, and this occurred before there was an observable decrease in tumor size. The integrin αvβ3 targeting ability of PEG-G3-(Gd-DTPA)6-(cRGD-DTPA)2 in vitro and in vivo was demonstrated. The 30-minute contrast washout percentage is a useful parameter for examining tumor angiogenesis and for the early assessment of antiangiogenic treatment response.

Diagnostic and therapeutic impact of MR enterography in Crohn's disease

AIM

To assess the impact of magnetic resonance enterography (MRE) on clinician diagnostic confidence and therapeutic strategy in patients under investigation for small bowel Crohn's disease.

MATERIAL AND METHODS

Gastroenterologists completed a proforma before and following MRE in 51 patients (mean age 35 years, 26 female) under investigation for small bowel Crohn's disease, indicating percentage confidence for presence/absence of small bowel involvement. In suspected disease, diagnostic confidence (using a scoring system from 1=no to 6=yes) was scored for subcategories: extent >30 cm (DE), terminal ileum (lTI), jejunal (JD), colonic disease (CoD), strictures (ST), activity (AD), extraluminal complications (EL), and surgical need (NS). Therapeutic strategy was recorded. Patients were divided into three groups: 1=suspected disease, MRE normal (n=15); 2=suspected disease, MRE abnormal (n=30); 3=no suspected disease, MRE normal (n=6). Binomial exact and paired t-tests were use to compare confidence pre and post-MRE.

RESULTS

Mean percentage confidence for the presence/absence of small bowel disease increased from 62 to 84% (p=0.003), 87 to 98% (p=0.0001), and 83 to 98% (p=0.005) after MRE for groups 1, 2, and 3, respectively. In suspected disease, confidence changed significantly for all of the subcategories (p<0.001) except EL in group 1. The percentage of patients with a confidence change ranged from 40% (CoD) to 87% (lTI; group 1) and from 7% (EL) to 93% (DE; group 2). Therapeutic strategy changed in 31/51 (61%, 95% CI 47-74%), 14 with a reduction in planned therapy and 17 with an increase.

CONCLUSION

MRE had a positive diagnostic impact in patients under investigation for small bowel Crohn's disease and this influenced therapeutic strategy in 61% of the patients.

Magnetic resonance imaging, knee arthroscopy, and clinical decision making: a descriptive study of five surgeons

OBJECTIVES

A randomized controlled trial (RCT) showed magnetic resonance imaging for patients waiting for knee arthroscopy did not reduce the number of arthroscopies. Our study aimed to identify decisions made by orthopedic surgeons about whether patients on a waiting list should proceed to arthroscopy, and to describe surgeons' decisions.

METHODS

Five surgeons were asked to Think Aloud (TA) as they made their decisions for twelve patients from the original RCT. Audiotapes of the decision making were transcribed for analysis.

RESULTS

For five patients, surgeons agreed about proceeding with arthroscopy, although reasoning differed. In no cases did surgeons agree about not proceeding to arthroscopy. Agreement was more likely in patients with clinically diagnosed meniscal abnormality, and less likely in patients with osteoarthritis.

CONCLUSIONS

Surgeons' decisions were influenced by patient wishes. For some patients, the decision to proceed with arthroscopy was based solely on clinical diagnosis; MRI may not be advantageous in these instances. Surgeons disagreed more often than they agreed about the decision to proceed with arthroscopy, particularly when OA was diagnosed. This has implications for decision making in the current NHS patient choice environment. Patients may choose a treatment provider from a list of available providers at time of original clinical assessment and diagnosis. The treating surgeon does not necessarily re-examine the patient until the day of surgery. Given the variation between surgeons about the merits of proceeding with arthroscopy, surgeons may end up in the invidious position of providing surgery to patients whom they do not believe will benefit from arthroscopy.

Early magnetic resonance imaging is unnecessary in patients with traumatic brain injury

INTRODUCTION

Computed tomography (CT) is routinely performed in traumatic brain injury (TBI). Magnetic resonance imaging (MRI) is considered more sensitive than CT for subtle abnormalities. Because CT does not always explain the posttraumatic neurologic examination, MRI is being performed with increasing frequency. Although MRI at a later stage may be of significant prognostic value, the role of early MRI is questionable. Our objective was to evaluate the role of early MRI in the initial management of patients with TBI.

METHODS

This is a 3-year prospective study (January 2005-December 2007) of adult patients with TBI who, in addition to CT, had MRI of the head within 48 hours of admission to the hospital. The findings from the two imaging studies were compared. The outcome was any change in management based on MRI findings.

RESULTS

We identified 123 trauma patients who had MRI within 18 hours +/- 14.5 hours of CT (median: 12 hours). In 82 (67%) patients, the findings of CT and MRI were identical. In the remaining 41 patients there were discrepancies between CT and MRI: 35 patients had slight differences in the location or size of the lesions found and six had minor brain lesion detected by MRI and not CT. Compared with patients who had identical CT and MRI, those who showed differences in the two tests had higher severity of head injury, lower initial blood pressure, and a higher rate of intubation. Based on CT findings, 78 (63%) patients received TBI-related interventions: 8 craniotomies, 12 intracranial pressure monitoring catheters, 14 mannitol infusions, and 72 antiepileptic medications. There was no change in treatment because of MRI.

CONCLUSION

Early MRI may be superior to CT in describing subtle TBI findings, but this information does not affect management. Head CT is the only imaging test necessary in the first 48 hours after TBI.

Open access to MRI for general practitioners: 12 years' experience at one institution -- a retrospective analysis

The aim of this study was to evaluate 12 years of general practitioner (GP) use of open access MRI services at a single London teaching hospital. A retrospective analysis of reports from all GP requests for MRI scans between 1994 and 2005 was performed. The date, scanned body part, and requester details from 1798 scans requested by 209 individual GPs over a continuous 12-year period were recorded. All scans were then graded into four categories based on the severity of reported findings from normal to gross abnormality. Over the study period, GP requests as a percentage of the total (MRI) department workload remained low at approximately 2.6%. Spine, knee and brain requests constituted 86% (n = 1546) of requested scans. 48% (n = 868) of scans were reported as normal or minor degenerative changes only. 26% (n = 466) of scans demonstrated serious pathology that was likely to warrant hospital consultant referral. There was a wide range of scans requested per requester, from 1 to 240 over the period, with an average of 8.5 scans per GP. In conclusion, any department wishing to set up open access to MRI services for GPs could cover the majority of requests by offering spine, knee and brain imaging. The percentage of normal report rates for GP requests is comparable with previous studies of outpatient referrals. A large variation in requesting patterns between GPs suggests the need for increased communication between GPs and imaging departments to optimise use of the service.

The contribution of cerebrospinal fluid oligoclonal bands to the early diagnosis of multiple sclerosis

Background

McDonald Criteria (MDC) have been validated in selected patients at high risk for multiple sclerosis (MS). However, possible overdiagnosis of MS can represent critical issues in less controlled clinical settings.

Objective

To assess the contribution of oligoclonal bands (OB) to MS diagnosis in current clinical practice.

Methods

We included all the patients admitted to our Department since 2001 who had undergone diagnostic workup for a possible MS diagnosis, followed up for at least 1 year. We assessed the accuracy of MDC, OB, and two MDC definitions of dissemination in space (DIS-MRI: fulfillment of MRI criteria, DIS-OB: two MRI lesions+OB).

Results

We included 118 patients (median follow-up 4.0 years). Twenty-eight cases received an alternative diagnosis, whereas none of these presented OB, 43% fulfilled the DIS-MRI criteria. OB were present in 70% of the remaining 90 patients. By the end of the follow-up, 56% of the diagnoses had converted to clinically definite MS and OB showed higher accuracy than DIS-MRI fulfillment (70% vs 58%). Moreover, after 1 year and at the end of the follow-up, DIS-OB yielded a higher Specificity level in comparison with DIS-MRI.

Conclusion

OB can improve overall diagnostic Accuracy by increasing Specificity and negative predictive value.

The effect of magnetic resonance imaging scans on knee arthroscopy: randomized controlled trial

PURPOSE

The purpose of this study was to investigate whether magnetic resonance imaging (MRI) in patients waiting for knee arthroscopy could reduce arthroscopy rates and improve patient outcome.

METHODS

A prospective randomized controlled trial was conducted in a teaching hospital setting. All participating patients had knee MRI before arthroscopy. In the intervention group the MRI report was seen by surgeons, and in the control group it was not. The primary outcome measure was the proportion of patients who did not have an arthroscopy. Secondary outcome measures included the Short Form 36, EuroQol EQ-5D, Knee Injury and Osteoarthritis Score, and Knee Society Score.

RESULTS

Surgeons changed both their diagnosis and management plan in 47% of patients in the intervention group compared with 1% in the control group, with no difference between groups in the proportion of patients who underwent an arthroscopy. In the intervention group 7 of 125 patients (5.6%) did not have an arthroscopy compared with 8 of 127 patients (6.3%) in the control group. In one instance a surgeon decided against arthroscopy based on the MRI report. There was no significant difference between groups in other outcome measures.

CONCLUSIONS

We found no effect of MRI on the decision to perform arthroscopy or patient outcome. Performing MRI in patients already on the waiting list for arthroscopy may not be effective in reducing utilization of surgery.

LEVEL OF EVIDENCE

Level I, therapeutic randomized controlled trial with no statistically significant difference but with narrow confidence intervals.

Cutting-edge imaging of the spine

Damage to the spinal cord may be caused by a wide range of pathologies and generally results in profound functional disability. A reliable diagnostic workup of the spine is very important because even relatively small lesions in this part of the central nervous system can have a profound clinical impact. MR imaging has become the method of choice for the detection and diagnosis of many spine disorders. Various innovative MR imaging methods have been developed to improve neuroimaging, including better pulse sequences and new MR contrast parameters. These new "cutting-edge" technologies have the potential to impact profoundly the ease and confidence of spinal disease interpretation and offer a more efficient diagnostic workup of patients suffering from spinal disease.

Analysis of diagnostic confidence and diagnostic accuracy: a unified framework

Diagnostic confidence has been used as a measure of diagnostic efficacy, but this measure in isolation fails to take into account incorrect diagnoses. Conventional analytical approaches of diagnostic confidence ignore associated diagnostic accuracy. To address this limitation, we introduce a unifying framework which incorporates diagnostic confidence, changes in diagnoses and ultimate accuracy. The framework is illustrated using data from a study in which 62 patients with acute abdominal pain prospectively underwent CT. Admitting surgeons documented their diagnoses and graded their diagnostic confidences (on a 5-point scale) on admission and again after CT. Our approach, unlike conventional analyses, incorporates knowledge of final diagnoses, obtained from surgery or 6 months follow up, in assessing the impact of the test (on a 9-point scale). Changes in pre- and post-CT confidence scores were assessed by the one-sample t-test comparing against zero change, with the test statistic acting as a standardized quantity allowing comparison between our and conventional methodological approaches. Overall, 52% (32/62) of patients were misdiagnosed on admission and 19% (12/62) had incorrect post-CT diagnoses. Diagnostic confidence following CT increased significantly compared with pre-CT confidence on applying both analytical methods, although the level of statistical significance was less marked using our approach. Mean (95% confidence interval) increase in confidence under conventional analysis was 1.32 (1.03, 1.62), with standardized score t = 8.90 [p<0.0001], whereas our method yielded 0.69 (0.25, 1.13), with standardized score t = 3.12 [p = 0.003]. Although both analytical methods led to the same inference regarding the efficacy of CT in the illustrative case study presented, they differed somewhat in degree. It is conceivable that disparate conclusions may emerge in other studies and circumstances. Failure to take adequate account of incorrect diagnoses is potentially misleading. We suggest that a comprehensive analysis of diagnostic confidence requires the incorporation of diagnostic accuracy.

Magnetic resonance imaging abnormalities in symptomatic and contralateral knees: prevalence and associations with traumatic history in general practice

BACKGROUND

After trauma, internal knee lesions are found in approximately two thirds of patients. However, magnetic resonance imaging abnormalities have also been described in asymptomatic volunteers.

HYPOTHESIS

Not all visualized lesions in symptomatic posttraumatic knees are the result of recent trauma; there are subgroups of lesions that may be preexistent.

STUDY DESIGN

Cross-sectional study (prevalence); Level of evidence, 2.

METHODS

Patients visiting their general practitioners after knee trauma were invited for magnetic resonance imaging of both knees. Prevalence of knee abnormalities was compared between symptomatic and asymptomatic knees. Multivariable analysis was performed to investigate the association between lesions that were seen in symptomatic and asymptomatic knees (ie, effusion and meniscal tears) and recent trauma, history of old trauma, age, and osteoarthritis.

RESULTS

In 134 participants, ligament lesions were found almost exclusively in symptomatic knees. Meniscal lesions and effusion were almost equally found in symptomatic and asymptomatic knees. Effusion was related to recent trauma (odds ratio, 14.0; 95% confidence interval, 5.0-39.6) and osteoarthritis (odds ratio, 4.7; 95% confidence interval, 1.4-15.5) but not to history of old trauma and age. Meniscal tears were more common in older patients (odds ratio, 1.09; 95% confidence interval, 1.05-1.12) but were not related to osteoarthritis. History of old trauma was more strongly related to the group of radial, longitudinal, and complex meniscal tears (odds ratio, 8.6; 95% confidence interval, 3.3-22.5) than to horizontal tears (odds ratio, 2.3; 95% confidence interval, 0.9-5.6). Recent trauma was not related to horizontal meniscal tears but was strongly related to other types of meniscal tears (odds ratio, 3.2; 95% confidence interval, 1.4-6.9).

CONCLUSION

Ligament knee lesions are most probably the result of recent trauma. Radial, longitudinal, and complex meniscal tears are strongly related to trauma, whereas horizontal meniscal tears and effusion may be preexistent in many cases.

Can breast MRI help in the management of women with breast cancer treated by neoadjuvant chemotherapy?

Contrast-enhanced (CE) MRI was used to monitor breast cancer response to neoadjuvant chemotherapy. Patients underwent CE MRI before and after therapy, together with conventional assessment methods (CAM). CE MRI was carried out at 1.5 T in the coronal plain with 3D sequences before and after bolus injection. An expert panel determined chemotherapy response using both CE MRI and CAM. Histopathological response in the surgical specimen was then used to determine the sensitivity and specificity of CE MRI and CAM. In total, 67 patients with 69 breast cancers were studied (mean age of 46 years). Tumour characteristics showed a high-risk tumour population: median size 49 mm: histopathological grade 3 (55%): oestrogen receptor (ER) negative (48%). Histopathological response was as follows: – complete pathological response (pCR) 17%; partial response (pPR) 68%; no response (NR) 15%. Sensitivity of CAM for pCR or pPR was 98% (CI 91–100%) and specificity was 50% (CI 19–81%). CE MRI sensitivity was 100% (CI 94–100%), and specificity was 80% (CI 44–97%). The absolute agreement between assessment methods and histopathology was marginally higher for CE MRI than CAM (81 vs 68%; P=0.09). In 71%, CE MRI increased diagnostic knowledge, although in 20% it was judged confusing or incorrect. The 2nd MRI study significantly increased diagnostic confidence, and in 19% could have changed the treatment plan. CE MRI persistently underestimated minimal residual disease. In conclusion, CE MRI of breast cancer proved more reliable for predicting histopathological response to neoadjuvant chemotherapy than conventional assessment methods.