Measuring the value of MRI: Comparative effectiveness & outcomes research

Effects of the Fasting-Postprandial State on Arterial Spin Labeling MRI-Based Cerebral Perfusion Quantification in Alzheimer's Disease

BACKGROUND

The fasting-postprandial state remains an underrecognized confounding factor for quantifying cerebral blood flow (CBF) in the cognitive assessment and differential diagnosis of Alzheimer's disease (AD).

PURPOSE

To investigate the effects of fasting-postprandial state on arterial spin labeling (ASL)-based CBF in AD patients.

STUDY TYPE

Prospective.

SUBJECTS

Ninety-two subjects (mean age = 62.5 ± 6.4 years; females 29.3%), including 30 with AD, 32 with mild cognitive impairment (MCI), and 30 healthy controls (HCs). Differential diagnostic models were developed with a 4:1 training to testing set ratio.

FIELD STRENGTH/SEQUENCE

3-T, T1-weighted imaging using gradient echo and pseudocontinuous ASL imaging using turbo spin echo.

ASSESSMENT

Two ASL scans were acquired to quantify fasting state and postprandial state regional CBFs based on an automated anatomical labeling atlas. Two-way ANOVA was used to assess the effects of fasting/postprandial state and disease state (AD, MCI, and HC) on regional CBF. Pearson's correlation analysis was conducted between regional CBF and cognitive scores (Mini-Mental State Examination [MMSE] and Montreal Cognitive Assessment [MoCA]). The diagnostic performances of the fasting state, postprandial state, and mixed state (random mixing of the fasting and postprandial state CBF) in differential diagnosis of AD were conducted using support vector machine and logistic regression models.

STATISTICAL TESTS

Two-way ANOVA, Pearson's correlation, and area under the curve (AUC) of diagnostic model were performed. P values <0.05 indicated statistical significance.

RESULTS

Fasting-state CBF was correlated with cognitive scores in more brain regions (17 vs. 4 [MMSE] and 15 vs. 9 [MoCA]) and had higher absolute correlation coefficients than postprandial-state CBF. In the differential diagnosis of AD patients from MCI patients and HCs, fasting-state CBF outperformed mixed-state CBF, which itself outperformed postprandial-state CBF.

DATA CONCLUSION

Compared with postprandial CBF, fasting-state CBF performed better in terms of cognitive score correlations and in differentiating AD patients from MCI patients and HCs.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 3.

Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

Humans are exposed to a complex mix of man-made electric and magnetic fields (MFs) at many different frequencies, at home and at work. Epidemiological studies indicate that there is a positive relationship between residential/domestic and occupational exposure to extremely low frequency electromagnetic fields and some types of cancer, although some other studies indicate no relationship. In this review, after an introduction on the MF definition and a description of natural/anthropogenic sources, the epidemiology of residential/domestic and occupational exposure to MFs and cancer is reviewed, with reference to leukemia, brain, and breast cancer. The in vivo and in vitro effects of MFs on cancer are reviewed considering both human and animal cells, with particular reference to the involvement of reactive oxygen species (ROS). MF application on cancer diagnostic and therapy (theranostic) are also reviewed by describing the use of different magnetic resonance imaging (MRI) applications for the detection of several cancers. Finally, the use of magnetic nanoparticles is described in terms of treatment of cancer by nanomedical applications for the precise delivery of anticancer drugs, nanosurgery by magnetomechanic methods, and selective killing of cancer cells by magnetic hyperthermia. The supplementary tables provide quantitative data and methodologies in epidemiological and cell biology studies. Although scientists do not generally agree that there is a cause-effect relationship between exposure to MF and cancer, MFs might not be the direct cause of cancer but may contribute to produce ROS and generate oxidative stress, which could trigger or enhance the expression of oncogenes.

MRI Utility in Hand Surgery

Background: Magnetic resonance imaging (MRI) is frequently used in the diagnosis of upper extremity conditions. We hypothesize that the results often do not change treatment. The purpose of the present study was to prospectively assess the extent to which MRI findings alter patient management. Methods: Ten hand surgeons who were ordering an MRI (elbow or distal) completed a standardized questionnaire. Prior to obtaining the MRI, the surgeon recorded their pre-MRI diagnosis and recommended treatment if no MRI could be obtained. Following the MRI, the surgeon recorded their post-MRI diagnosis and ultimate treatment recommendation. Finally, the surgeon answered whether the MRI was helpful, and if so, how it helped guide their treatment. Descriptive statistics were performed. Results: One hundred eighty-seven MRIs were ordered. The most common reasons for ordering an MRI were the evaluation of presumed occult scaphoid fracture, ulnar wrist pain, metacarpophalangeal joint collateral ligament injury, and mass. The surgeon agreed with the radiologist's interpretation of the MRI in 88% of cases. Overall, surgeons found the MRI to be helpful in 92% of cases, and the recommended treatment changed as a result of the MRI findings in 19% (35/187) of patients. Of these 35 patients, 9 had a pre-MRI diagnosis that was concordant with the MRI findings, but the proposed management of the patient changed after the MRI. Conclusions: Hand surgeons infrequently change their treatment plan based on MRI findings. Given the importance of cost-efficient care, indications for use of MRI may need to be re-evaluated.

Imaging-based patient-reported outcomes (PROs) database: How we do it

Patient-reported outcomes (PROs) provide an essential understanding of the impact a condition or treatment has on a patient, while complementing other, more traditional outcomes information like survival and time to symptom resolution. PROs have become increasingly important in medicine with the push toward patient-centered care. The creation of a PROs database within an institution or practice provides a way to collect, understand, and use this kind of patient feedback to inform quality improvement and develop the evidence base for medical decision-making and on a larger scale could potentially help determine national standards of care and treatment guidelines. This paper provides a first-hand account of our experience setting up an imaging-based PROs database at our institution and is organized into steps the reader can follow for creating a PROs database of their own. Given the limited use of PROs within both diagnostic and interventional radiology, we hope our paper stimulates a new interest among radiologists who may have never considered outcomes work in the past.

Evaluation of Diagnostic Tests

As technology advances, diagnostic tests continue to improve and each year, we are presented with new alternatives to standard procedures. Given the plethora of diagnostic alternatives, diagnostic tests must be evaluated to determine their place in the diagnostic armamentarium. The first step involves determining the accuracy of the test, including the sensitivity and specificity, positive and negative predictive values, likelihood ratios for positive and negative tests, and receiver operating characteristic (ROC) curves. The role of the test in a diagnostic pathway has then to be determined, following which the effect on patient outcome should be examined.

Viewing the Emphasis on State-of-the-Art Magnetic Nanoparticles: Synthesis, Physical Properties, and Applications in Cancer Theranostics

Cancer-related mortality is a leading cause of death among both men and women around the world. Target-specific therapeutic drugs, early diagnosis, and treatment are crucial to reducing the mortality rate. One of the recent trends in modern medicine is "Theranostics," a combination of therapeutics and diagnosis. Extensive interest in magnetic nanoparticles (MNPs) and ultrasmall superparamagnetic iron oxide nanoparticles (NPs) has been increasing due to their biocompatibility, superparamagnetism, less-toxicity, enhanced programmed cell death, and auto-phagocytosis on cancer cells. MNPs act as a multifunctional, noninvasive, ligand conjugated nano-imaging vehicle in targeted drug delivery and diagnosis. In this review, we primarily discuss the significance of the crystal structure, magnetic properties, and the most common method for synthesis of the smaller sized MNPs and their limitations. Next, the recent applications of MNPs in cancer therapy and theranostics are discussed, with certain preclinical and clinical experiments. The focus is on implementation and understanding of the mechanism of action of MNPs in cancer therapy through passive and active targeting drug delivery (magnetic drug targeting and targeting ligand conjugated MNPs). In addition, the theranostic application of MNPs with a dual and multimodal imaging system for early diagnosis and treatment of various cancer types including breast, cervical, glioblastoma, and lung cancer is reviewed. In the near future, the theranostic potential of MNPs with multimodality imaging techniques may enhance the acuity of personalized medicine in the diagnosis and treatment of individual patients.