Aaron P. Kamer

Relative cerebral blood volume from dynamic susceptibility contrast perfusion in the grading of pediatric primary brain tumors

IntroductionThe aim of this study is to evaluate the utility of relative cerebral blood volume (rCBV) data from dynamic susceptibility contrast (DSC) perfusion in grading pediatric primary brain tumors.MethodsA retrospective blinded review of 63 pediatric brain tumors with DSC perfusion was performed independently by two neuroradiologists. A diagnosis of low- versus high-grade tumor was obtained from conventional imaging alone. Maximum rCBV (rCBVmax) was measured from manual ROI placement for each reviewer and averaged. Whole-tumor CBV data was obtained from a semi-automated approach. Results from all three analyses were compared to WHO grade.ResultsBased on conventional MRI, the two reviewers had a concordance rate of 81xa0% (ku2009=u20090.62). Compared to WHO grade, the concordant cases accurately diagnosed high versus low grade in 82xa0%. A positive correlation was demonstrated between manual rCBVmax and tumor grade (ru2009=u20090.30, Pu2009=u20090.015). ROC analysis of rCBVmax (area under curve 0.65, 0.52–0.77, Pu2009=u20090.03) gave a low-high threshold of 1.38 with sensitivity of 92xa0% (74–99xa0%), specificity of 40xa0% (24–57xa0%), NPV of 88xa0% (62–98xa0%), and PPV of 50xa0% (35–65xa0%) Using this threshold on 12 discordant tumors between evaluators from conventional imaging yielded correct diagnoses in nine patients. Semi-automated analysis demonstrated statistically significant differences between low- and high-grade tumors for multiple metrics including average rCBV (Pu2009=u20090.027).ConclusionsDespite significant positive correlation with tumor grade, rCBV from pediatric brain tumors demonstrates limited specificity, but high NPV in excluding high-grade neoplasms. In selective patients whose conventional imaging is nonspecific, an rCBV threshold may have further diagnostic value.

Diffusion Imaging for Tumor Grading of Supratentorial Brain Tumors in the First Year of Life

BACKGROUND AND PURPOSE: Supratentorial tumors in the first year of life are typically large and heterogeneous at presentation, making differentiation of these CNS neoplasms on pre-operative imaging difficult. We hypothesize that the ADC value can reliably differentiate high- versus low-grade supratentorial tumors in this patient population. MATERIALS AND METHODS: A blinded review of ADC maps was performed on 19 patients with histologically proved supratentorial brain tumors diagnosed within the first year of life. Minimum ADC values obtained by region of interest from 2 neuroradiologists were averaged and compared with World Health Organization tumor grade. ADC values for the entire tumor were also obtained by use of a semi-automated histogram method and compared with World Health Organization tumor grade. Data were analyzed by use of Spearman ρ and Student t test, with a value of P < .05 considered statistically significant. RESULTS: For the manual ADC values, a significant negative correlation was found between the mean minimum ADC and tumor grade (P = .0016). A significant difference was found between the mean minimum ADC of the low-grade (1.14 × 10−3 mm2/s ± 0.30) and high-grade tumors (0.64 × 10−3 mm2/s ± 0.28) (P = .0018). Likewise, the semi-automated method demonstrated a significant negative correlation between the lowest 5th (P = .0002) and 10th (P = .0009) percentile individual tumor ADC values and tumor grade, a significant difference between the mean 5th and 10th percentile ADC values of the low-grade and high-grade groups (P = .0028), and a significant positive correlation with values obtained by manual region-of-interest placement (P < .000001). CONCLUSIONS: ADC maps can differentiate high- versus low-grade neoplasms for supratentorial tumors presenting in the first year of life, given the significant negative correlation between ADC values and tumor grade.

A case of natalizumab-associated progressive multifocal leukoencephalopathy with repeated negative CSF JCV testing

The development of progressive multifocal leukoencephalopathy (PML) in patients treated with natalizumab is a well-known potential risk. Diagnosis of PML can be confounded in patients with multiple sclerosis (MS) if new demyelinating lesions develop, and the sensitivity of existing diagnostic tests is less than ideal. In the case presented here, four samples of cerebrospinal fluid tested negative for John Cunningham virus (JCV) DNA by polymerase chain reaction, yet brain biopsy eventually proved positive by immunohistochemistry. A review of the limitations of existing clinical diagnostic tests is addressed, and we review the most recent literature on the proper management of natalizumab-treated MS patients.

Meaningful Peer Review in Radiology: A Review of Current Practices and Potential Future Directions

The current practice of peer review within radiology is well developed and widely implemented compared with other medical specialties. However, there are many factors that limit current peer review practices from reducing diagnostic errors and improving patient care. The development of meaningful peer review requires a transition away from compliance toward quality improvement, whereby the information and insights gained facilitate education and drive systematic improvements that reduce the frequency and impact of diagnostic error. The next generation of peer review requires significant improvements in IT functionality and integration, enabling features such as anonymization, adjudication by multiple specialists, categorization and analysis of errors, tracking, feedback, and easy export into teaching files and other media that require strong partnerships with vendors. In this article, the authors assess various peer review practices, with focused discussion on current limitations and future needs for meaningful peer review in radiology.

Diagnostic imaging of intracranial metastasis.

1 In both asymptomatic and symptomatic patients, imaging of the brain has a primary role in the detection of brain metastases and is important for subsequent patient management and treatment. This article will focus on the routine and advanced imaging techniques used to diagnose and monitor treatment of both new and recurrent intracranial metastases. Specific imaging patterns and potential pitfalls in the discernment between intracranial metastatic disease and other brain masses, intracranial infections, and the effects of treatment will be discussed.

Transitioning to Independent Practice: A Successful Fourth-Year Radiology Resident Curriculum

THE PROBLEM In 2007, the ABR announced changes to the structure and timing of the diagnostic radiology board examinations that would effectively consolidate testing into two examinations, a qualifying examination at the end of the third year of residency and a certifying examination 15 months after graduation. At the same time, the Radiology Residency Review Committee announced that the new board examination structure would enable a functional partitioning of radiology residency into a 3-year “core” period before the qualifying examination, followed by the fourth year of residency after it. The core years, it was reasoned, would be a time to focus on acquiring the fundamental concepts and skills of radiology, and the fourth year would be an opportunity for trainees to gain additional experience in subspecialty areas of interest that would allow them to bring valueadded skills to patients and clinical care providers once in practice. In the decade since these joint announcements, programs have worked hard to define their new fourth-year resident curricula. The redesigned fourth year provides opportunities for residents to focus on _________________________________

Radiological diagnosis of drop metastases from paediatric brain tumours using combination of 2D and 3D MRI sequences

AIMnTo evaluate spinal magnetic resonance imaging (MRI) examinations using a combination of two-dimensional (2D) and three-dimensional (3D) MRI sequences for diagnosis of drop metastases.nnnMATERIALS AND METHODSnFifty-five paediatric patients with primary brain tumours werexa0evaluated for drop metastases at initial presentation using spinal MRI including sagittal 2D T1-weighted (W) contrast-enhanced (+C), axial 3D T1W+C volumetric interpolated breath-hold (VIBE), and sagittal 3D T2W SPACE (Sampling Perfection with Application optimised Contrasts using different flip angle Evolutions).nnnRESULTSnThe MRI false-negative rate was 4%, and cerebrospinal fluid (CSF) false-negative rate was 16% (p=0.07). The 3D T1W+C VIBE increased the number of drop metastases detected in 42% of patients. Drop metastases were more conspicuous in 25% of patients on 3D T2W SPACE.nnnCONCLUSIONnSpinal MRI examinations including 2D and 3D sequences demonstrate characteristics that may improve radiological diagnosis of drop metastases.

Toward Data-Driven Radiology Education-Early Experience Building Multi-Institutional Academic Trainee Interpretation Log Database (MATILDA).

The residency review committee of the Accreditation Council of Graduate Medical Education (ACGME) collects data on resident exam volume and sets minimum requirements. However, this data is not made readily available, and the ACGME does not share their tools or methodology. It is therefore difficult to assess the integrity of the data and determine if it truly reflects relevant aspects of the resident experience. This manuscript describes our experience creating a multi-institutional case log, incorporating data from three American diagnostic radiology residency programs. Each of the three sites independently established automated query pipelines from the various radiology information systems in their respective hospital groups, thereby creating a resident-specific database. Then, the three institutional resident case log databases were aggregated into a single centralized database schema. Three hundred thirty residents and 2,905,923 radiologic examinations over a 4-year span were catalogued using 11 ACGME categories. Our experience highlights big data challenges including internal data heterogeneity and external data discrepancies faced by informatics researchers.