Author: jross

Jeffrey Ross • Mayo Clinic, Phoenix

Dr. Jeffrey S. Ross is a Professor of Radiology at the Mayo Clinic College of Medicine, and practices neuroradiology at the Mayo Clinic in Phoenix, Arizona. His publications include over 100 peer-reviewed articles, nearly 60 non-refereed articles, 33 book chapters, and 10 books. He was an AJNR Senior Editor from 2006-2015, is a member of the editorial board for 3 other journals, and a manuscript reviewer for 10 journals. He became Editor-in-Chief of the AJNR in July 2015. He received the Gold Medal Award from the ASSR in 2013.

Two-Center Experience in the Endovascular Treatment of Ruptured and Unruptured Intracranial Aneurysms Using the WEB Device: A Retrospective Analysis

Fellows’ Journal Club

The authors performed a retrospective analysis of all ruptured and unruptured aneurysms treated with a WEB device between August 2014 and February 2017. Primary outcome measures included the feasibility of implantation and the angiographic outcome. Secondary outcome measures included the clinical outcome at discharge and procedural complications. One hundred two aneurysms in 101 patients, including 37 (36.3%) ruptured aneurysms, were treated with the WEB device. Implantation was successful in 98 (96.1%) aneurysms. Additional devices (stents/coils) were necessary in 15.3% (15/98) of aneurysms. Delayed aneurysm ruptures have not been observed during the follow-up period to date. They conclude that the WEB device offers a safe and effective treatment option for broad-based intracranial aneurysms without the need for dual antiplatelet therapy.

Dynamic Contrast-Enhanced MRI–Derived Intracellular Water Lifetime (τi): A Prognostic Marker for Patients with Head and Neck Squamous Cell Carcinomas

Editor’s Choice

The authors evaluated 60 patients with dynamic contrast-enhanced MR imaging before treatment. Median, mean intracellular water molecule lifetime, and volume transfer constant values from metastatic nodes were computed from each patient. Kaplan-Meier analyses were performed to associate mean intracellular water molecule lifetime and volume transfer constant and their combination with overall survival and beyond. Patients with high mean intracellular water molecule lifetime had overall survival significantly prolonged by 5 years compared with those with low mean intracellular water molecule lifetime. Patients with high mean intracellular water molecule lifetime had significantly longer overall survival at long-term duration than those with low mean intracellular water molecule lifetime. Volume transfer constant was a significant predictor for only the 5-year follow-up period. They conclude that a combined analysis of mean intracellular water molecule lifetime and volume transfer constant provided the best model to predict overall survival in patients with squamous cell carcinomas of the head and neck.

Do Fluid-Attenuated Inversion Recovery Vascular Hyperintensities Represent Good Collaterals before Reperfusion Therapy?

Fellows’ Journal Club

The authors evaluated 244 consecutive patients eligible for reperfusion therapy with MCA stroke and pretreatment MR imaging with both FLAIR and PWI. The FLAIR vascular hyperintensity score was based on ASPECTS, ranging from 0 (no FLAIR vascular hyperintensity) to 7 (FLAIR vascular hyperintensities abutting all ASPECTS cortical areas). The hypoperfusion intensity ratio was defined as the ratio of the time-to-maximum >10-second over time-to-maximum >6-second lesion volumes. The FLAIR vascular hyperintensities were more extensive in patients with good collaterals than those with poor collaterals. The FLAIR vascular hyperintensity score was independently associated with good collaterals. They conclude that the ASPECTS assessment of FLAIR vascular hyperintensities could be used to rapidly identify patients more likely to benefit from reperfusion therapy.

Reproducibility of Deep Gray Matter Atrophy Rate Measurement in a Large Multicenter Dataset

Editor’s Choice

The authors assessed the reproducibility of 2 automated segmentation software packages (FreeSurfer and the FMRIB Integrated Registration and Segmentation Tool) by quantifying the volume changes of deep GM structures by using back-to-back MR imaging scans from the Alzheimer Disease Neuroimaging Initiative’s multicenter dataset in 562 subjects. Back-to-back differences in 1-year percentage volume change were approximately 1.5–3.5 times larger than the mean measured 1-year volume change of those structures. They conclude that longitudinal deep GM atrophy measures should be interpreted with caution and that deep GM atrophy measurement techniques require substantially improved reproducibility, specifically when aiming for personalized medicine.

Deep Brain Nuclei T1 Shortening after Gadobenate Dimeglumine in Children: Influence of Radiation and Chemotherapy

Fellows’ Journal Club

The authors reviewed clinical charts and images of patients 18 years of age or younger with ≥4 gadobenatedimeglumine–enhanced MRIs for 6 years. Seventy-six children (60 unconfounded by treatment, 16 with radiochemotherapy) met the selection criteria. T1 signal intensity ratios for the dentate to pons and globus pallidus to thalamus were calculated and correlated with number of injections, time interval, and therapy. Among the 60 children without radiochemotherapy, only 2 had elevated T1 signal intensity ratios. Twelve of the 16 children with radiochemotherapy showed elevated signal intensity ratios. Statistical analysis demonstrated a significant signal intensity ratio change for the number of injections. Compared with published adult series, children show a similar pattern of T1 hyperintense signal changes of the dentate and globus pallidus after multiple gadobenatedimeglumine injections. The T1 signal changes in children are accelerated by radiochemotherapy.

MR Elastography Analysis of Glioma Stiffness and IDH1-Mutation Status

Editor’s Choice

Tumor stiffness properties were prospectively quantified in 18 patients with histologically proved gliomas using MR elastography. Images were acquired on a 3T MR imaging unit with a vibration frequency of 60 Hz. Tumor stiffness was compared with unaffected contralateral white matter, across tumor grade, and by IDH1-mutation status. Gliomas were softer than healthy brain parenchyma, 2.2kPa compared with 3.3kPa, with grade IV tumors softer than grade II. MR elastography demonstrated that not only were gliomas softer than normal brain but the degree of softening was directly correlated with tumor grade and IDH1-mutation status.

Journal Scan – This Month in Other Journals, January 2018

Wilkinson RJ, Rohlwink U, Misra UK, et al. Tuberculous meningitis. Nat Rev Neurol. 2017;13(10):581-598. doi:10.1038/nrneurol.2017.120.

Tuberculosis remains a global health problem, with an estimated 10.4 million cases and 1.8 million deaths resulting from the disease in 2015. The most lethal and disabling form of tuberculosis is tuberculous meningitis, for which more than 100,000 new cases are estimated to occur per year. In adults, the best-documented risk factor for tuberculous meningitis is HIV‑1 co‑infection. Among HIV-infected individuals who live in areas where tuberculosis is highly endemic, the proportion of HIV‑1‑associated meningitis cases attributable to Mycobacterium tuberculosis can exceed 50%. Individuals with tuberculous meningitis and a HIV‑1 co‑infection have a twofold to threefold increase in relative risk of death from any cause with overall mortality around 40%, even in those individuals prescribed antiretroviral therapy. Drug-resistant tuberculous meningitis in people co‑infected with HIV‑1 has a particularly poor prognosis, approaching 100% mortality.

Bacterial replication must occur in the CNS for tuberculous meningitis pathogenesis to proceed. However, the bacillary load in the CSF rarely exceeds 100–1000 bacterial colonies per milliliter, and viable bacilli are difficult to detect in the majority of individuals. Early studies in experimental animal models showed that the meningitis syndrome and even death of tuberculin-sensitized animals could be induced by meningeal inoculation with dead bacilli. Much of the tissue damage is therefore attributed to a dysregulated host inflammatory response. Once bacilli have traversed the blood–brain barrier, they are taken up by microglia and can also replicate in these cells, leading to the induction of microglial cytokine and chemokine production.

The importance of infarction to long-term outcomes has led to interest in cranial vessel imaging. CTA has been used to define lesions in the anterior and posterior cerebral circulation, and has demonstrated that the supraclinoid portion of the internal carotid artery …

CT Texture Analysis Potentially Predicts Local Failure in Head and Neck Squamous Cell Carcinoma Treated with Chemoradiotherapy

Fellows’ Journal Club

This was a retrospective study including 62 patients diagnosed with primary head and neck squamous cellcarcinoma who underwent contrast-enhanced CT examinations for staging, followed by chemoradiotherapy. CT texture features of thewhole primary tumor were measured using an in-house developed Matlab-based texture analysis program. Histogram, gray-level co-occurrence matrix, gray-level run-length, gray-level gradient matrix, and Laws features were used for texture feature extraction. Three histogram features (geometric mean, harmonic, and fourth moment) and 4 gray-level run-length features (short-run emphasis, gray-level nonuniformity, run-length nonuniformity, and short-run low gray-level emphasis) were significant predictors of outcome.

Preoperative Cerebral Oxygen Extraction Fraction Imaging Generated from 7T MR Quantitative Susceptibility Mapping Predicts Development of Cerebral Hyperperfusion following Carotid Endarterectomy

Editor’s Choice

Seventy-seven patients with unilateral internal carotid artery stenosis underwent preoperative 3DT2*-weighted imaging using a multiple dipole-inversion algorithm with a 7T MR scanner. Quantitative susceptibility mapping images wereobtained, and oxygen extraction fraction maps were generated. Quantitative brain perfusion single-photon emission CT was alsoperformed before and immediately after carotid endarterectomy. Ten patients (13%) showed post–carotid endarterectomy hyperperfusion. Multivariate analysis showed that a high quantitative susceptibility mapping–oxygen extraction fraction ratio was significantly associated with the development of post–carotid endarterectomy hyperperfusion.

Setting the Stage for 2018: How the Changes in the American Joint Committee on Cancer/Union for International Cancer Control Cancer Staging Manual Eighth Edition Impact Radiologists

Fellows’ Journal Club

The updated eighth edition of the Cancer Staging Manual of the American Joint Committee on Cancer will be implemented in January 2018. There are multiple changes to the head and neck section of the manual, which will be relevant to radiologists participating in multidisciplinary head and neck tumor boards and reading pretreatment head and neck cancer scans.