De-identification of Medical Images with Retention of Scientific Research Value.

Online public repositories for sharing research data allow investigators to validate existing research or perform secondary research without the expense of collecting new data. Patient data made publicly available through such repositories may constitute a breach of personally identifiable information if not properly de-identified. Imaging data are especially at risk because some intricacies of the Digital Imaging and Communications in Medicine (DICOM) format are not widely understood by researchers. If imaging data still containing protected health information (PHI) were released through a public repository, a number of different parties could be held liable, including the original researcher who collected and submitted the data, the original researcher's institution, and the organization managing the repository. To minimize these risks through proper de-identification of image data, one must understand what PHI exists and where that PHI resides, and one must have the tools to remove PHI without compromising the scientific integrity of the data. DICOM public elements are defined by the DICOM Standard. Modality vendors use private elements to encode acquisition parameters that are not yet defined by the DICOM Standard, or the vendor may not have updated an existing software product after DICOM defined new public elements. Because private elements are not standardized, a common de-identification practice is to delete all private elements, removing scientifically useful data as well as PHI. Researchers and publishers of imaging data can use the tools and process described in this article to de-identify DICOM images according to current best practices.

Reproducibility of detecting silent cerebral infarcts in pediatric sickle cell anemia.

Detecting silent cerebral infarcts on magnetic resonance images (MRIs) in children with sickle cell anemia is challenging, yet reproducibility of readings has not been examined in this population. We evaluated consensus rating, inter-, and intra-grader agreement associated with detecting silent cerebral infarct on screening MRI in the Silent Infarct Transfusion Trial. Three neuroradiologists provided consensus decisions for 1073 MRIs. A random sample of 53 scans was reanalyzed in blinded fashion. Agreement between first and second consensus ratings was substantial (κ = 0.70, P < .0001), as was overall intergrader agreement (κ = 0.76, P < .0001). In the test-retest sample, intragrader agreement ranged from κ of 0.57 to 0.76. Consensus decisions were more concordant when MRIs contained more than one larger lesions. Routine use of MRI to screen for silent cerebral infarcts in the research setting is reproducible in sickle cell anemia and agreement among neuroradiologists is sufficient.

Magnetic resonance angiography-defined intracranial vasculopathy is associated with silent cerebral infarcts and glucose-6-phosphate dehydrogenase mutation in children with sickle cell anaemia.

Silent cerebral infarct (SCI) is the most commonly recognized cause of neurological injury in sickle cell anaemia (SCA). We tested the hypothesis that magnetic resonance angiography (MRA)-defined vasculopathy is associated with SCI. Furthermore, we examined genetic variations in glucose-6-phosphate dehydrogenase (G6PD) and HBA (α-globin) genes to determine their association with intracranial vasculopathy in children with SCA. Magnetic resonance imaging (MRI) of the brain and MRA of the cerebral vasculature were available in 516 paediatric patients with SCA, enrolled in the Silent Infarct Transfusion (SIT) Trial. All patients were screened for G6PD mutations and HBA deletions. SCI were present in 41·5% (214 of 516) of SIT Trial children. The frequency of intracranial vasculopathy with and without SCI was 15·9% and 6·3%, respectively (P < 0·001). Using a multivariable logistic regression model, only the presence of a SCI was associated with increased odds of vasculopathy (P = 0·0007, odds ratio (OR) 2·84; 95% Confidence Interval (CI) = 1·55-5·21). Among male children with SCA, G6PD status was associated with vasculopathy (P = 0·04, OR 2·78; 95% CI = 1·04-7·42), while no significant association was noted for HBA deletions. Intracranial vasculopathy was observed in a minority of children with SCA, and when present, was associated with G6PD status in males and SCI.

Incidental findings on brain magnetic resonance imaging of children with sickle cell disease.

OBJECTIVE: We describe the prevalence and range of incidental intracranial abnormalities identified through MRI of the brain in a large group of children screened for a clinical trial. METHODS: We included 953 children between 5 and 14 years of age who were screened with MRI of the brain for the Silent Infarct Transfusion Trial. All had sickle cell anemia or sickle beta-null thalassemia. MRI scans were interpreted by 3 neuroradiologists. MRI scans reported to have any abnormality were reviewed by 2 study neuroradiologists. Incidental findings were classified into 4 categories, that is, no, routine, urgent, or immediate referral recommended. Cerebral infarctions and vascular lesions were not considered incidental and were excluded. RESULTS: We identified 63 children (6.6% [95% confidence interval: 5.1%-8.4%]) with 68 incidental intracranial MRI findings. Findings were classified as urgent in 6 cases (0.6%), routine in 25 cases (2.6%), and no referral required in 32 cases (3.4%). No children required immediate referral. Two children with urgent findings underwent surgery in the subsequent 6 months. CONCLUSION: In this large cohort of children, incidental intracranial findings were identified for 6.6%, with potentially serious or urgent findings for 0.6%.

Design of the silent cerebral infarct transfusion (SIT) trial.

BACKGROUND: Silent cerebral infarct (SCI) is the most common cause of serious neurological disease in sickle cell anemia (SCA), affecting approximately 22% of children. The goal of this trial is to determine whether blood transfusion therapy will reduce further neurological morbidity in children with SCI, and if so, the magnitude of this benefit. PROCEDURE: The Silent Cerebral Infarct Transfusion (SIT) Trial includes 29 clinical sites and 3 subsites, a Clinical Coordinating Center, and a Statistical and Data Coordinating Center, to test the following hypothesis: prophylactic blood transfusion therapy in children with SCI will result in at least an 86% reduction in the rate of subsequent overt strokes or new or progressive cerebral infarcts as defined by magnetic resonance imaging (MRI) of the brain. The intervention is blood transfusion versus observation. Two hundred and four participants (102 in each treatment assignment) will ensure 85% power to detect the effect necessary to recommend transfusion therapy (86% reduction), after accounting for 10% drop out and 19% crossover rates. MRI examination of the brain is done at screening, immediately before randomization and study exit. Each randomly assigned participant receives a cognitive test battery at study entry, 12-18 months later, and study exit and an annual neurological examination. Blood is obtained from all screened participants for a biologic repository containing serum and a renewable source of DNA. CONCLUSION: The SIT Trial could lead to a change in standard care practices for children affected with SCA and SCI, with a consequent reduction in neurological morbidity.

Silent Cerebral Infarct Transfusion (SIT) trial imaging core: application of novel imaging information technology for rapid and central review of MRI of the brain.

The Silent Cerebral Infarct Multicenter Transfusion (SIT) Trial is a multi-institutional intervention trial in which children with silent cerebral infarcts are randomized to receive either blood transfusion therapy or observation (standard care) for 36 months. The SIT Trial is scheduled to enroll approximately 1,880 children with sickle cell disease from 29 clinical sites in the United States, Canada, UK, and France. Each child undergoes a screening magnetic resonance imaging (MRI) of the brain to detect the presence of silent cerebral infarct-like lesions, a pre-randomization (baseline) MRI and exit MRI to determine if there are new or enlarged cerebral infarcts, using a designated, prospective imaging protocol. The objective of this manuscript is to describe the innovative method used to process and adjudicate imaging studies for an international trial with a primary endpoint that includes neuroimaging. Institution investigators at each site were provided with computer hardware and software for transmission of MRI images that allow them to strip the scans of all personal information and add unique study identifiers. Three neuroradiologists at separate academic centers review MRI studies and determine the presence or absence of silent cerebral infarct-like lesions. Their findings are subsequently placed on web-based case report forms and sent to the Statistical Coordinating Center. The average time from imaging center receipt of the MRI study to the radiology committee report back to the local site is less than two working days. This novel strategy was designed to maximize efficiency and minimize cost of a complex large multicenter trial that depends heavily on neuroimaging for entry criteria and assessment for the primary outcome measures. The technology, process, and expertise used in the SIT Trial can be adapted to virtually any clinical research trial with digital imaging requirements.

Tools for managing image flow in the modality to clinical-image-review chain.

Web-based clinical-image viewing is commonplace in large medical centers. As demands for product and performance escalate, physicians, sold on the concept of "any image, anytime, anywhere," fret when image studies cannot be viewed in a time frame to which they are accustomed. Image delivery pathways in large medical centers are oftentimes complicated by multiple networks, multiple picture archiving and communication systems (PACS), and multiple groups responsible for image acquisition and delivery to multiple destinations. When studies are delayed, it may be difficult to rapidly pinpoint bottlenecks. Described here are the tools used to monitor likely failure points in our modality to clinical-image-viewing chain and tools for reporting volume and throughput trends. Though perhaps unique to our environment, we believe that tools of this type are essential for understanding and monitoring image-study flow, re-configuring resources to achieve better throughput, and planning for anticipated growth. Without such tools, quality clinical-image delivery may not be what it should.