Imaging Manifestations of Pseudoprogression in Metastatic Melanoma Nodes Injected with Talimogene Laherparepvec: Initial Experience

Talimogene laherparepvec is an oncolytic virus recently approved for targeted treatment of advanced melanoma. Because of an inflammatory reaction, treated lesions may increase in size and develop infiltrative margins that can be construed as disease progression or extracapsular spread. In this report, we describe our initial experience imaging the response of metastatic nodes injected with talimogene laherparepvec. Six of 12 nodes (50%) showed growth from baseline followed by decreased size, 5 of 12 nodes (42%) showed a downward size trend, and 1 node showed continued increase in size. Seven of 9 nodes (78%) developed infiltrative margins at a median of 79 days, and 6 of 9 (67%) nodes became necrotic at a median of 76 days after injection, all showing decreased size at final follow-up. An increase in the size of nodes injected with talimogene laherparepvec does not necessarily indicate progression. Infiltrative margins are also frequently seen and may be confused with extracapsular disease.

Folate and vitamin B12 concentrations are associated with plasma DHA and EPA fatty acids in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

This study aimed to examine the association between vitamin B6, folate and vitamin B12 biomarkers and plasma fatty acids in European adolescents. A subsample from the Healthy Lifestyle in Europe by Nutrition in Adolescence study with valid data on B-vitamins and fatty acid blood parameters, and all the other covariates used in the analyses such as BMI, Diet Quality Index, education of the mother and physical activity assessed by a questionnaire, was selected resulting in 674 cases (43 % males). B-vitamin biomarkers were measured by chromatography and immunoassay and fatty acids by enzymatic analyses. Linear mixed models elucidated the association between B-vitamins and fatty acid blood parameters (changes in fatty acid profiles according to change in 10 units of vitamin B biomarkers). DHA, EPA) and n-3 fatty acids showed positive associations with B-vitamin biomarkers, mainly with those corresponding to folate and vitamin B12. Contrarily, negative associations were found with n-6:n-3 ratio, trans-fatty acids and oleic:stearic ratio. With total homocysteine (tHcy), all the associations found with these parameters were opposite (for instance, an increase of 10 nmol/l in red blood cell folate or holotranscobalamin in females produces an increase of 15·85 µmol/l of EPA (P value <0·01), whereas an increase of 10 nmol/l of tHcy in males produces a decrease of 2·06 µmol/l of DHA (P value <0·05). Positive associations between B-vitamins and specific fatty acids might suggest underlying mechanisms between B-vitamins and CVD and it is worth the attention of public health policies.

Early-Stage Glioblastomas: MR Imaging-Based Classification and Imaging Evidence of Progressive Growth

BACKGROUND AND PURPOSE

The serial imaging changes describing the growth of glioblastomas from small to large tumors are seldom reported. Our aim was to classify the imaging patterns of early-stage glioblastomas and to define the order of appearance of different imaging patterns that occur during the growth of small glioblastomas.

MATERIALS AND METHODS

Medical records and preoperative MR imaging studies of patients diagnosed with glioblastoma between 2006 and 2013 were reviewed. Patients were included if their MR imaging studies showed early-stage glioblastomas, defined as small MR imaging lesions detected early in the course of the disease, demonstrating abnormal signal intensity but the absence of classic imaging findings of glioblastoma. Each lesion was reviewed by 2 neuroradiologists independently for location, signal intensity, involvement of GM and/or WM, and contrast-enhancement pattern on MR imaging.

RESULTS

Twenty-six patients with 31 preoperative MR imaging studies met the inclusion criteria. Early-stage glioblastomas were classified into 3 types and were all hyperintense on FLAIR/T2-weighted images. Type I lesions predominantly involved cortical GM (n = 3). Type II (n = 12) and III (n = 16) lesions involved both cortical GM and subcortical WM. Focal contrast enhancement was present only in type III lesions at the gray-white junction. Interobserver agreement was excellent (κ = 0.95; P < .001) for lesion-type classification. Transformations of lesions from type I to type II and type II to type III were observed on follow-up MR imaging studies. The early-stage glioblastomas of 16 patients were pathologically confirmed after imaging progression to classic glioblastoma.

CONCLUSIONS

Cortical lesions may be the earliest MR imaging-detectable abnormality in some human glioblastomas. These cortical tumors may progress to involve WM.

Efficacy of Double-Blind Peer Review in an Imaging Subspecialty Journal

BACKGROUND AND PURPOSE

Many scientific journals use double-blind peer review to minimize potential reviewer bias concerning publication recommendations. However, because neuroradiology is a relatively small subspecialty, this process may be limited by prior knowledge of the authors' work or associated institutions. We sought to investigate the efficacy of reviewer blinding and determine the impact that unblinding may have on manuscript acceptance.

MATERIALS AND METHODS

For manuscripts submitted to the American Journal of Neuroradiology (AJNR) from January through June 2015, reviewers completed a brief anonymous questionnaire after submitting their evaluations, assessing whether they were familiar with the research or had knowledge of the authors or institutions from which the work originated.

RESULTS

The response rate for 1079 questionnaires was 98.8%; 12.9% of reviewers knew or suspected that they knew authors, and 15.3% knew or suspected that they knew the associated institutions. Reviewers correctly identified the authors in 90.3% of cases and correctly stated the institutions in 86.8% of cases. Unblinding resulted from self-citation in 34.1% for both authorship and institutions. The acceptance rate when reviewers knew or suspected that they knew the authors was 57/137 (41.6%) and 262/929 (28.2%) when reviewers did not. The acceptance rate when reviewers knew or suspected that they knew the institutions was 60/163 (36.8%) and 259/903 (28.7%) when they did not. The Fisher exact test showed that author (P < .038) and institution (P < .039) familiarity was associated with greater manuscript acceptance.

CONCLUSIONS

While the AJNR process of double-blind peer review minimizes reviewer bias, perceived knowledge of the author and institution is associated with a higher rate of manuscript acceptance.

Fibrous Histiocytoma-like Spindle-Cell Proliferation in the Nipple After Body-Piercing

We report the case of a 19-year-old pregnant woman who presented with a nipple tumor. The lesion consisted in a spindle-cell proliferation with histologic features similar to those of fibrous histiocytoma, with a highly vascularized stroma. Although it showed low mitotic activity, scattered marked atypical cells with prominent nucleoli were identified, thus raising concern about the benign nature of the tumor. Immunohistochemical evaluation revealed that the spindle cells were diffusely positive for vimentin, focally positive for CD68, and negative for all the other tested antibodies. The patient had a total excision of the lesion and she is free of disease after 30 months. To our knowledge this is the first reported case of a lesion of this type in the nipple after body-piercing.

T1 Signal-Intensity Increase in the Dentate Nucleus after Multiple Exposures to Gadodiamide: Intraindividual Comparison between 2 Commonly Used Sequences

BACKGROUND AND PURPOSE

Different T1-weighted sequences have been used for qualitative and quantitative evaluation of T1 signal intensity related to gadolinium deposition in the dentate nucleus in patients who underwent several enhanced MR imaging studies. Our purpose was to perform an intraindividual qualitative and quantitative comparison between T1-weighted spin-echo and 3D magnetization-prepared rapid acquisition of gradient echo sequences in patients who had multiple exposures to gadodiamide.

MATERIALS AND METHODS

Our retrospectively selected population included 18 patients who underwent at least 3 administrations of gadodiamide and had a baseline and a final MR imaging performed with both T1-weighted sequences. Qualitative and quantitative analyses were independently performed. Dentate nucleus/middle cerebellar peduncle signal-intensity ratios and signal changes between the baseline and final examinations were compared by using the Wilcoxon signed rank test. Correlation between quantitative and qualitative evaluations was assessed by using a polyserial correlation test.

RESULTS

The differences between the 2 sequences for both baseline and last examination dentate nucleus/middle cerebellar peduncle ratios were statistically significant (P = .008 and P = .006, respectively); however, the signal-intensity changes of the ratios with time were not (P = .64). The correlation between the qualitative and quantitative analysis was very strong (near-perfect) (r = 0.9) for MPRAGE and strong (r = 0.63) for spin-echo sequences.

CONCLUSIONS

T1-weighted spin-echo and MPRAGE sequences cannot be used interchangeably for qualitative or quantitative analysis of signal intensity in the dentate nucleus in patients who received gadodiamide. Baseline and final examination ratios should be evaluated across time by using the same sequence. Qualitative analysis performed with MPRAGE correlated better with quantitative analysis and may offer advantages over spin-echo sequences for research purposes.

Gadolinium-Based Contrast Agent Accumulation and Toxicity: An Update

In current practice, gadolinium-based contrast agents have been considered safe when used at clinically recommended doses in patients without severe renal insufficiency. The causal relationship between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with renal insufficiency resulted in new policies regarding the administration of these agents. After an effective screening of patients with renal disease by performing either unenhanced or reduced-dose-enhanced studies in these patients and by using the most stable contrast agents, nephrogenic systemic fibrosis has been largely eliminated since 2009. Evidence of in vivo gadolinium deposition in bone tissue in patients with normal renal function is well-established, but recent literature showing that gadolinium might also deposit in the brain in patients with intact blood-brain barriers caught many individuals in the imaging community by surprise. The purpose of this review was to summarize the literature on gadolinium-based contrast agents, tying together information on agent stability and animal and human studies, and to emphasize that low-stability agents are the ones most often associated with brain deposition.

Subspecialty Virtual Impact Factors within a Dedicated Neuroimaging Journal

BACKGROUND AND PURPOSE

The growing number of subspecialties within neuroradiology compete for pages in neuroradiology journals. We performed a bibliometric analysis of the American Journal of Neuroradiology to identify the virtual Impact Factor of different journal subsections and article topics.

MATERIALS AND METHODS

Original Research and Review Articles published in American Journal of Neuroradiology during 2010-2012 were evaluated. The journal section for each article was recorded, and the number of citations was evaluated by using the Web of Science database. Numbers of citations within the first 2 years after publication were evaluated, normalized to the 2013 journal Impact Factor (for American Journal of Neuroradiology, 3.675), and used to calculate a virtual Impact Factor for different journal subsections.

RESULTS

One thousand forty-nine Original Research and Review Articles were published during this time, which obtained an average of 6.59 citations each within their first 2 years after publication; 91.8% of articles obtained at least 1 citation. Expedited Publications had the greatest number of citations, averaging 43.7 citations each (virtual Impact Factor, 24.39), followed by Review Articles averaging 9.39 citations each (virtual Impact Factor 5.23). Virtual Impact Factors for other sections were the following: Interventional, 4.54; Brain, 3.70; Pediatrics, 2.91; Functional, 2.74; Head & Neck, 2.24; and Spine, 1.86. Virtual Impact Factors for article topics were the following: interventional, 4.75; functional/advanced, 3.79; brain, 3.66; pediatrics, 2.99; head and neck, 2.46; and spine, 2.32.

CONCLUSIONS

Citation patterns of Original Research and Review Articles in American Journal of Neuroradiology varied widely on the basis of subsections. Understanding the citation patterns of specific topics and subsections of a journal may aid authors and editors in evaluating the appropriate balance among various topics and allow authors to determine whether their articles are being cited at a level expected for similar ones in a journal.

Screening for self-plagiarism in a subspecialty-versus-general imaging journal using iThenticate

BACKGROUND AND PURPOSE

Self-plagiarism is a form of research misconduct that can dilute the credibility and reputation of a scientific journal, as well as the represented specialty. Journal editors are aware of this problem when reviewing submissions and use on-line plagiarism-analysis programs to facilitate detection. The American Journal of Neuroradiology (AJNR) uses iThenticate to screen several submitted original research manuscripts selected for review per issue and retrospectively assesses 3 issues per year. The prevalence of self-plagiarism in AJNR was compared with that in Radiology; the necessity and cost of more extensive screening in AJNR were evaluated.

MATERIALS AND METHODS

The self-duplication rate in AJNR original research articles was compared with that in Radiology, a general imaging journal that screens all submitted original research manuscripts selected for review by using iThenticate. The rate of self-duplication in original research articles from 2 randomly selected 2012 AJNR issues was compared with the rate in the prior year to gauge the need for more extensive screening. A cost analysis of screening all submitted original research manuscripts selected for review by using iThenticate was performed.

RESULTS

Using an empiric 15% single-source duplication threshold, we found that the rate of significant self-plagiarism in original research articles was low for both journals. While AJNR had more articles exceeding this threshold, most instances were insignificant. Analyzing 2 randomly chosen issues of AJNR for single-source duplication of >15% in original research articles yielded no significant differences compared with an entire year. The approximate annual cost of screening all submitted original research manuscripts selected for review was US $6800.00.

CONCLUSIONS

While the rate of self-plagiarism was low in AJNR and similar to that in Radiology, its potential cost in negative impact on AJNR and the subspecialty of neuroradiology justifies the costs of broader screening.

Evidence levels for neuroradiology articles: low agreement among raters

BACKGROUND AND PURPOSE

Because evidence-based articles are difficult to recognize among the large volume of publications available, some journals have adopted evidence-based medicine criteria to classify their articles. Our purpose was to determine whether an evidence-based medicine classification used by a subspecialty-imaging journal allowed consistent categorization of levels of evidence among different raters.

MATERIALS AND METHODS

One hundred consecutive articles in the American Journal of Neuroradiology were classified as to their level of evidence by the 2 original manuscript reviewers, and their interobserver agreement was calculated. After publication, abstracts and titles were reprinted and independently ranked by 3 different radiologists at 2 different time points. Interobserver and intraobserver agreement was calculated for these radiologists.

RESULTS

The interobserver agreement between the original manuscript reviewers was -0.2283 (standard error = 0.0000; 95% CI, -0.2283 to -0.2283); among the 3 postpublication reviewers for the first evaluation, it was 0.1899 (standard error = 0.0383; 95% CI, 0.1149-0.2649); and for the second evaluation, performed 3 months later, it was 0.1145 (standard error = 0.0350; 95% CI, 0.0460-0.1831). The intraobserver agreement was 0.2344 (standard error = 0.0660; 95% CI, 0.1050-0.3639), 0.3826 (standard error = 0.0738; 95% CI, 0.2379-0.5272), and 0.6611 (standard error = 0.0656; 95% CI, 0.5325-0.7898) for the 3 postpublication evaluators, respectively. These results show no-to-fair interreviewer agreement and a tendency to slight intrareviewer agreement.

CONCLUSIONS

Inconsistent use of evidence-based criteria by different raters limits their utility when attempting to classify neuroradiology-related articles.