Dose dependence of accelerated repopulation in head and neck cancer: Supporting evidence and clinical implications

Publication date: Available online 10 March 2018
Source:Radiotherapy and Oncology
Author(s): Igor Shuryak, Eric J. Hall, David J. Brenner
Background and purposeAccelerated repopulation (AR) can compromise tumor control after conventional radiotherapy for fast-growing tumors. Standard AR models assume it begins at a fixed time, with repopulation rates independent of the number of clonogens killed. We investigate the validity and significance of an alternative model where onset-time and rate of AR depend on the number of clonogens killed, and thus on dose and dose-fractionation.Materials and methodsWe analyzed tumor control (TCP) from randomized trials for head and neck cancer (HNC, 7283 patients), featuring wide ranges of doses, times, and fractionation-schemes. We used the linear-quadratic model with the standard dose-independent AR model, or with an alternative dose-dependent model, where AR onset and rate depend on clonogen killing.ResultsThe alternative dose-dependent model of AR provides significantly-improved descriptions of a wide range of randomized clinical data, relative to the standard dose-independent model. This preferred model predicts that, for currently-used HNC fractionation schemes, the last 5 fractions do not increase TCP, but simply compensate for increased accelerated repopulation.ConclusionsThe preferred dose-dependent AR model predicts that, for standard fractionation schemes currently used to treat HNC, the final week (5 fractions) could be eliminated without compromising TCP, but resulting in significantly decreased late sequelae due to the lower overall dose.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FHgYjq

Use of extracranial radiation therapy in metastatic melanoma patients receiving immunotherapy

Publication date: Available online 11 March 2018
Source:Radiotherapy and Oncology
Author(s): Prashant Gabani, Clifford G. Robinson, George Ansstas, Tanner M. Johanns, Jiayi Huang
PurposeExplore the patterns of use of extracranial radiation therapy (RT) in metastatic melanoma patients receiving immunotherapy, its potential association with OS, the impact of the site and timing of RT on clinical outcomes when combined with immunotherapy.Materials and methodsPatients with extracranial metastatic melanoma who received immunotherapy with or without extracranial RT from 2004 to 2013 were obtained from the National Cancer Database. Multivariable Cox regression analysis was used to evaluate factors associated with overall survival (OS). Subset analyses comparing outcomes in patients receiving RT to bone metastases versus soft tissue metastases were also performed. OS was compared using the Kaplan–Meier and log-rank statistics.ResultsA total of 1675 patients were identified: 1387 received immunotherapy alone and 288 received immunotherapy plus RT. An increase in the utilization of RT as well as SBRT was noted over time. The rate of RT use was 11.5% (0% with SBRT) in 2004 and gradually rose to 19.8% (27.0% with SBRT) in 2013 (P = 0.04). The median OS was 15.4 vs. 19.4 months in the immunotherapy plus RT and immunotherapy alone groups, respectively (P = 0.02). However, on multivariable analysis, RT was not associated with worse OS. The poor OS in the RT group was confined to the patients who received RT to bone metastases, but not in patients who received RT to soft tissue metastases. In subset analyses of patients irradiated to soft tissue, RT administered at least 30 days before immunotherapy was associated with a higher OS than RT administered within 30 days or 30 days after immunotherapy: median 26.1 months vs. 16.0 months (P = 0.009) vs. 15.4 months (P = 0.004), respectively.ConclusionsThis study demonstrates that extracranial RT plays an increasing role in the management of metastatic melanoma patients in the era of immunotherapy. The site and the timing of RT may have important interaction with immunotherapy, and need to be carefully considered in future clinical trials.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tyi4td

The Impact of Gadolinium Deposition on Radiology Practice: An International Survey of Radiologists

Publication date: Available online 7 February 2018
Source:Current Problems in Diagnostic Radiology
Author(s): Ryan T. Fitzgerald, Vikas Agarwal, Jenny K. Hoang, Frank Gaillard, Andrew Dixon, Emanuel Kanal
Rationale and ObjectivesBrain deposition of gadolinium following the administration of gadolinium-based contrast agents (GBCAs) was initially reported in 2014. Gadolinium deposition is now recognized as a dose-dependent consequence of exposure. The potential clinical implications are not yet understood. The purpose of this study was to determine radiologists' reporting practices in response to gadolinium deposition.Materials and MethodsAn electronic survey querying radiologists' practices regarding gadolinium deposition was distributed by Radiopaedia.org from November-December 2015.ResultsOur study sample included 94 total respondents (50% academic; 27% private practice; 23% hybrid) from 30 different countries (USA 18%). Fifty-seven (62%) radiologists had observed brain gadolinium deposition on MRI brain studies howerver more than half of these (30 of 57) reported detecting dentate T1 shortening only rarely (<1/month). Among respondents, 58% (52 of 89) do not or would not include the finding in the radiology report; only 12 (13%) report the finding in the impression of their reports. The most common reason for not reporting gadolinium deposition was the risk of provoking unnecessary patient anxiety (29%, 20 of 70). Recent data on gadolinium deposition has led to a reported practice change in 24 of 87 (28%) of respondents.ConclusionRecognition of, and attitudes toward, brain gadolinium deposition were inconsistent in this worldwide sample. Most surveyed radiologists do not routinely report dentate T1shortening as a marker of gadolinium deposition. Fear of provoking patient/clinician anxiety and an incomplete understanding of the implications of gadolinium deposition contribute to inconsistencies in reporting.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2GeBtlE

Use of extracranial radiation therapy in metastatic melanoma patients receiving immunotherapy

Explore the patterns of use of extracranial radiation therapy (RT) in metastatic melanoma patients receiving immunotherapy, its potential association with OS, the impact of the site and timing of RT on clinical outcomes when combined with immunotherapy.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2p98FTB

Dose dependence of accelerated repopulation in head and neck cancer: Supporting evidence and clinical implications

Accelerated repopulation (AR) can compromise tumor control after conventional radiotherapy for fast-growing tumors. Standard AR models assume it begins at a fixed time, with repopulation rates independent of the number of clonogens killed. We investigate the validity and significance of an alternative model where onset-time and rate of AR depend on the number of clonogens killed, and thus on dose and dose-fractionation.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2IkiZRd

Extraction of permanent maxillary teeth without palatal injection: a meta-analysis

Publication date: Available online 7 February 2018
Source:Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Author(s): Li Cui, Zhuyu Zhang, Ling Xu, Jiao Huang, Dongqing Yin
ObjectiveThe objective of this meta-analysis was to assess the operation success rates of extracting maxillary teeth without palatal injection.Study DesignPubMed, Cochrane Library, Embase, SinoMed and the references of the identified full-text articles were searched for relevant studies published until June 2017 that met the eligibility criteria. Experimental data were combined by meta-analysis using RevMan 5.3 soft- ware.Results7 randomized controlled trials were included in this meta-analysis. Compared with the control groups (were given the combination of buccal and palatal anesthesia recommended by the textbook, also known as routine Infiltration anesthesia), experimental group (single buccal anesthesia) for the removal of maxillary permanent teeth at conventional doses, which resulted in a reduction in the success rate (OR = 0.14, 95% CI = 0.07–0.27, P < 0.00001).ConclusionsThe results revealed that the success rate of the removal of the maxillary permanent teeth has undoubtedly been reduced by the lack of palatal injections. However, larger and higher quality tests are needed to confirm and optimize the effect of this anesthetic procedure.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2DgYLEr

Whole-Tumor Histogram and Texture Analyses of DTI for Evaluation of IDH1-Mutation and 1p/19q-Codeletion Status in World Health Organization Grade II Gliomas.

Whole-Tumor Histogram and Texture Analyses of DTI for Evaluation of IDH1-Mutation and 1p/19q-Codeletion Status in World Health Organization Grade II Gliomas.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Park YW, Han K, Ahn SS, Choi YS, Chang JH, Kim SH, Kang SG, Kim EH, Lee SK

Abstract
BACKGROUND AND PURPOSE: Prediction of the isocitrate dehydrogenase 1 (IDH1)-mutation and 1p/19q-codeletion status of World Health Organization grade ll gliomas preoperatively may assist in predicting prognosis and planning treatment strategies. Our aim was to characterize the histogram and texture analyses of apparent diffusion coefficient and fractional anisotropy maps to determine IDH1-mutation and 1p/19q-codeletion status in World Health Organization grade II gliomas.
MATERIALS AND METHODS: Ninety-three patients with World Health Organization grade II gliomas with known IDH1-mutation and 1p/19q-codeletion status (18 IDH1 wild-type, 45 IDH1 mutant and no 1p/19q codeletion, 30 IDH1-mutant and 1p/19q codeleted tumors) underwent DTI. ROIs were drawn on every section of the T2-weighted images and transferred to the ADC and the fractional anisotropy maps to derive volume-based data of the entire tumor. Histogram and texture analyses were correlated with the IDH1-mutation and 1p/19q-codeletion status. The predictive powers of imaging features for IDH1 wild-type tumors and 1p/19q-codeletion status in IDH1-mutant subgroups were evaluated using the least absolute shrinkage and selection operator.
RESULTS: Various histogram and texture parameters differed significantly according to IDH1-mutation and 1p/19q-codeletion status. The skewness and energy of ADC, 10th and 25th percentiles, and correlation of fractional anisotropy were independent predictors of an IDH1 wild-type in the least absolute shrinkage and selection operator. The area under the receiver operating curve for the prediction model was 0.853. The skewness and cluster shade of ADC, energy, and correlation of fractional anisotropy were independent predictors of a 1p/19q codeletion in IDH1-mutant tumors in the least absolute shrinkage and selection operator. The area under the receiver operating curve was 0.807.
CONCLUSIONS: Whole-tumor histogram and texture features of the ADC and fractional anisotropy maps are useful for predicting the IDH1-mutation and 1p/19q-codeletion status in World Health Organization grade II gliomas.

PMID: 29519794 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FuBLni

MRI Features Can Predict 1p/19q Status in Intracranial Gliomas.

MRI Features Can Predict 1p/19q Status in Intracranial Gliomas.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Lasocki A, Gaillard F, Gorelik A, Gonzales M

Abstract
BACKGROUND AND PURPOSE: The 2016 revision of the World Health Organization Classification of Tumors of the Central Nervous System mandates codeletion of chromosomes 1p and 19q for the diagnosis of oligodendroglioma. We studied whether conventional MR imaging features could predict 1p/19q status.
MATERIALS AND METHODS: Patients with previous 1p/19q testing were identified through pathology department records, typically performed on the basis of an oligodendroglial component on routine histology; 69 patients met the inclusion criteria. Preoperative imaging of patients with grade II or III gliomas was retrospectively assessed by 2 neuroradiologists, blinded to the 1p/19q status. Thirteen MR imaging features were first assessed in a small initial cohort (n = 10), after which the criteria were narrowed for the remaining patients as a validation cohort.
RESULTS: There was 85% agreement between radiologists for the overall prediction of 1p/19q status in the validation cohort, with an accuracy of 84%. The presence of >50% T2-FLAIR mismatch and calcification was found to be the most useful for predicting 1p/19q status. The >50% T2-FLAIR mismatch variable was demonstrated in 14 tumors and had 100% specificity for identifying a noncodeleted tumor (P = .001), with 97% interobserver correlation. Calcification was visualized in 7 tumors, 6 of which were 1p/19q codeleted (specificity, 97%; P = .006), with 100% interobserver correlation.
CONCLUSIONS: The presence of >50% T2-FLAIR mismatch is highly predictive of a noncodeleted tumor, while calcifications suggest a 1p/19q codeleted tumor. If formal 1p/19q testing is not possible, a combined MR imaging-histologic assessment may improve the diagnostic accuracy over histology alone.

PMID: 29519793 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FprjRU

Prenatal Brain MR Imaging: Reference Linear Biometric Centiles between 20 and 24 Gestational Weeks.

Prenatal Brain MR Imaging: Reference Linear Biometric Centiles between 20 and 24 Gestational Weeks.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Conte G, Milani S, Palumbo G, Talenti G, Boito S, Rustico M, Triulzi F, Righini A, Izzo G, Doneda C, Zolin A, Parazzini C

Abstract
BACKGROUND AND PURPOSE: Evaluation of biometry is a fundamental step in prenatal brain MR imaging. While different studies have reported reference centiles for MR imaging biometric data of fetuses in the late second and third trimesters of gestation, no one has reported them in fetuses in the early second trimester. We report centiles of normal MR imaging linear biometric data of a large cohort of fetal brains within 24 weeks of gestation.
MATERIALS AND METHODS: From the data bases of 2 referral centers of fetal medicine, accounting for 3850 examinations, we retrospectively collected 169 prenatal brain MR imaging examinations of singleton pregnancies, between 20 and 24 weeks of gestational age, with normal brain anatomy at MR imaging and normal postnatal neurologic development. To trace the reference centiles, we used the CG-LMS method.
RESULTS: Reference biometric centiles for the developing structures of the cerebrum, cerebellum, brain stem, and theca were obtained. The overall interassessor agreement was adequate for all measurements.
CONCLUSIONS: Reference biometric centiles of the brain structures in fetuses between 20 and 24 weeks of gestational age may be a reliable tool in assessing fetal brain development.

PMID: 29519792 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FvqO4L

Fast and Robust Unsupervised Identification of MS Lesion Change Using the Statistical Detection of Changes Algorithm.

Fast and Robust Unsupervised Identification of MS Lesion Change Using the Statistical Detection of Changes Algorithm.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Nguyen TD, Zhang S, Gupta A, Zhao Y, Gauthier SA, Wang Y

Abstract
We developed a robust automated algorithm called statistical detection of changes for detecting morphologic changes of multiple sclerosis lesions between 2 T2-weighted FLAIR brain images. Results from 30 patients showed that statistical detection of changes achieved significantly higher sensitivity and specificity (0.964, 95% CI, 0.823-0.994; 0.691, 95% CI, 0.612-0.761) than with the lesion-prediction algorithm (0.614, 95% CI, 0.410-0.784; 0.281, 95% CI, 0.228-0.314), while resulting in a 49% reduction in human review time (P = .007).

PMID: 29519791 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2GavWwd

Targeting the Clot in Acute Stroke.

Targeting the Clot in Acute Stroke.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Lövblad KO

PMID: 29519790 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FwXydM

Congenital Aqueductal Stenosis: Findings at Fetal MRI That Accurately Predict a Postnatal Diagnosis.

Congenital Aqueductal Stenosis: Findings at Fetal MRI That Accurately Predict a Postnatal Diagnosis.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Heaphy-Henault KJ, Guimaraes CV, Mehollin-Ray AR, Cassady CI, Zhang W, Desai NK, Paldino MJ

Abstract
BACKGROUND AND PURPOSE: Congenital aqueductal stenosis is a common cause of prenatal ventriculomegaly. An accurate diagnosis provides prognostic information and may guide obstetric management. The purpose of this study was to identify specific anatomic findings on prenatal MR imaging that can be used as predictors of congenital aqueductal stenosis.
MATERIALS AND METHODS: Prenatal and postnatal MRIs of fetuses referred to our institution for ventriculomegaly between June 2008 and August 2015 were reviewed. Imaging findings in postnatally confirmed congenital aqueductal stenosis (disease group) were compared with those of ventriculomegaly cases from other causes (control group). Univariate analysis was performed using the Fisher exact test and the Wilcoxon rank test, and multivariate analysis, via the random forest method.
RESULTS: Forty-three cases of ventriculomegaly had a confirmed postnatal diagnosis of congenital aqueductal stenosis. Thirty-two ventriculomegaly cases negative for congenital aqueductal stenosis were included in the control group. Dominant findings associated with an accurate prenatal diagnosis of congenital aqueductal stenosis on multivariate analysis included the following: enlarged inferior third ventricular recesses, enlargement of the lateral ventricles and third ventricle, and an abnormal corpus callosum. Findings that significantly increase the probability of congenital aqueductal stenosis (high positive predictive value) included the following: enlarged third ventricular recesses, aqueduct funneling, hemorrhage in the cerebral aqueduct, ventricular diverticulum, rhombencephalosynapsis, and dystroglycanopathy-related cerebellar dysplasia.
CONCLUSIONS: Our study identified specific characteristics on fetal MR imaging that can be used as predictors of the diagnosis of congenital aqueductal stenosis. Most of these findings are secondary to the obstructive nature of the resulting hydrocephalus. Common associated malformations such as rhombencephalosynapsis and dystroglycanopathies should also increase the suspicion of congenital aqueductal stenosis when present with ventriculomegaly.

PMID: 29519789 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FrRgR2

Long-Term Outcomes of Patients with Stent Tips Embedded into Internal Carotid Artery Branches during Aneurysm Coiling.

Long-Term Outcomes of Patients with Stent Tips Embedded into Internal Carotid Artery Branches during Aneurysm Coiling.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Ban SP, Kwon OK, Lee SU, Bang JS, Oh CW, Jeong HJ, Cho MJ, Jeong EA, Kim T

Abstract
BACKGROUND AND PURPOSE: During stent-assisted coiling of ICA aneurysms, stent tips are sometimes unintentionally embedded into ICA branches. Stent tips can be visualized because they have radiopaque markers. Concerns regarding stent tip misplacement include risks of artery perforation and occlusion. The aim of this study was to evaluate the long-term outcomes of ICA branches with embedded stent tips.
MATERIALS AND METHODS: ICA branches with embedded stent tips were identified among 35 patients with unruptured ICA aneurysms treated with stent-assisted coiling between November 2003 and November 2014. Patient clinical and angiographic outcomes associated with the embedded stent tip were analyzed.
RESULTS: Most of the 35 studied aneurysms were paraclinoid ICA aneurysms (n = 30). The most commonly involved ICA branch was the posterior communicating artery (26 patients, 74.3%), followed by the anterior choroidal artery (8 patients, 22.9%) and ophthalmic artery (1 patient, 2.9%). During the follow-up period (38.6 ± 17.9 months), no new neurologic deficits developed. Neither hemorrhagic nor thromboembolic events occurred. Angiography was performed during the final follow-up evaluation at a mean of 32.7 ± 18.0 months, and all ICA branches with embedded stent tips showed patent blood flow without severe luminal narrowing.
CONCLUSIONS: In our experience, placement of a stent tip into ICA branches during stent-assisted coiling was not associated with any major adverse events.

PMID: 29519788 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FvnIh6

Quantitative Phase-Contrast MR Angiography to Measure Hemodynamic Changes in Idiopathic Intracranial Hypertension.

Quantitative Phase-Contrast MR Angiography to Measure Hemodynamic Changes in Idiopathic Intracranial Hypertension.

AJNR Am J Neuroradiol. 2018 Mar 08;:

Authors: Juhász J, Lindner T, Riedel C, Margraf NG, Jansen O, Rohr A

Abstract
BACKGROUND AND PURPOSE: Idiopathic intracranial hypertension is a syndrome of raised intracranial pressure of unknown etiology. Few MR imaging-based studies have investigated arterial and venous blood flow in these patients. Results are inconclusive, and to our knowledge, no comparison of the hemodynamic parameters before and after CSF pressure reduction has been published. The aim of this study was to assess the short-term effects of normalizing CSF pressure on intracranial flow to better understand the pathophysiology of idiopathic intracranial hypertension.
MATERIALS AND METHODS: In this study, we performed quantitative MR imaging-derived flow measurements of brain-supplying arteries and draining veins/dural sinuses to visualize hemodynamic changes in patients with idiopathic intracranial hypertension before and after therapy by lumbar puncture in comparison with a healthy control group.
RESULTS: We found differences in patients before and after lumbar puncture in the calculated resistance and pulsatility indices in the superior sagittal sinus. Venous pulsatility showed a negative correlation with CSF pressure in untreated patients. Additionally, there was a trend toward lower flow in the superior sagittal sinus in patients compared with healthy controls. Flow in the internal jugular veins was significantly reduced by lumbar puncture, and the resistance and pulsatility indices differed in patients and controls. The arterial flow was not influenced by pressure normalization.
CONCLUSIONS: The results of the present study indicate that venous but not arterial blood flow differs in patients compared with controls and that calculating resistance and pulsatility indices may contribute to assessing short-term hemodynamic changes in patients with diagnosed idiopathic intracranial hypertension before and after CSF diversion.

PMID: 29519787 [PubMed - as supplied by publisher]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2Ghub0B

Modified Lung-RADS Improves Performance of Screening LDCT in a Population with High Prevalence of Non–smoking-related Lung Cancer

Publication date: Available online 9 March 2018
Source:Academic Radiology
Author(s): Hui-Ting Hsu, En-Kuei Tang, Ming-Ting Wu, Carol C. Wu, Chia-Hao Liang, Chi-Shen Chen, Guang-Yuan Mar, Ruay-Sheng Lai, Jo-Ching Wang, Chuan-Ling Wu, Yi-Luan Huang, Fu-Zong Wu
ObjectivesWe proposed a modification of the ACR Lung Imaging Reporting and Data System (Lung-RADS) to clarify the characteristics of subsolid nodules with categories 1–11, and to compare the diagnostic accuracy with Lung-RADS and National Lung Screening Trial criteria in an Asian population with high prevalence of adenocarcinoma.MethodsWe analyzed a retrospective cohort of 1978 consecutive healthy subjects (72.8% nonsmoker) who underwent low-dose computed tomography from August 2013 to October 2014 (1084 men, 894 women). Lung-RADS categories 2 and 3 were modified to include subcategories of 2A/2B/2C and 3A/3B/3C, respectively. Clinical information and nodule characteristics were recorded. Receiver operating characteristic curves were used to compare diagnostic accuracy at different cutoffs.ResultsThirty-two subjects (30 nonsmokers) had pathology-proven adenocarcinoma spectrum lesions in the follow-up period (1.6 ± 0.5 years). Modified Lung-RADS, using modified Lung-RADS category 2C as cutoff, had an area under the curve (AUC) of 0.973 in predicting adenocarcinoma spectrum lesions (sensitivity of 100%, specificity of 89.3%), which was significantly higher than that of Lung-RADS (AUC = 0.815, P < .001) and National Lung Screening Trial (AUC = 0.906, P < .001). Furthermore, modified Lung-RADS showed an AUC of 0.992 in predicting invasive adenocarcinoma (sensitivity of 95%, specificity of 97.8%) when category 3B was used as cutoff.ConclusionsModified Lung-RADS may substantially improve sensitivity while maintaining specificity for detection of adenocarcinoma spectrum lesions in an Asian population. Compared to Lung-RADS, it has enhanced ability to differentiate invasive from indolent adenocarcinoma by more refined subclassification of subsolid nodules using two cutoff values of category 2C and 3B. The effect of using modified Lung-RADS in clinical practice must be carefully studied in prospective large cohort studies.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2FvUPl7

Attitudes of Radiology Program Directors Toward MD-PhD Trainees, Resident Research Productivity, and Dedicated Research Time

Publication date: Available online 9 March 2018
Source:Academic Radiology
Author(s): Petrice M. Cogswell, Lori A. Deitte, Edwin F. Donnelly, Victoria L. Morgan, Reed A. Omary
Rationale and ObjectivesThe percentage of clinical scientists in radiology has historically been low. Increasing the pipeline of trainees interested in research could occur by recruiting MD-PhD trainees and providing protected research time during residency. The purpose of this work is to assess the attitudes of radiology program directors toward MD-PhD trainees, resident research productivity, and dedicated research time.MethodsAn online survey was sent to residency program directors of all diagnostic radiology departments that received National Institutes of Health (NIH) awards in 2014 (n = 63). Survey questions included program size; perception of overall performance, clinical performance, and research productivity of MD-PhD residents compared to non-PhD residents; and presence of dedicated research time. Responses comparing MD-PhD residents to non-PhD residents were reported as a five-point Likert scale. Student t test was used to assess for significance (alpha = 0.05).ResultsResponse rate was 37%. Clinical performance of MD-PhD residents was judged inferior (P < .05) to non-PhD residents, although that of all residents engaged in research trended toward superiority compared to those not involved in research. Dedicated research time is offered by 61% of programs in years R1–R3 and all programs in year R4. Research productivity during residency was judged to be similar (P = .5) between MD-PhD and non-PhD residents.ConclusionsSurvey results suggest that clinical performance during residency and research involvement is often individually based and difficult to generalize based on prior PhD training. All programs offered dedicated research time, and the vast majority of residents were reported to engage in research during residency, which may increase the pipeline of trainees interested in an academic career.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2GatHZP

Qualitative CT Criterion for Subsolid Nodule Subclassification

Publication date: Available online 9 March 2018
Source:Academic Radiology
Author(s): Po An Chen, Eric P. Huang, Lu Yang Shih, En Kuei Tang, Chu Chun Chien, Ming Ting Wu, Fu Zong Wu
Rationale and ObjectivesThe main aim of this study was to evaluate the clinical validity and correlation with pathologic invasiveness in the pulmonary adenocarcinoma spectrum based on the novel qualitative computed tomography criterion for subsolid nodule (SSN) classification, which classified SSN into pure ground-glass nodule, heterogeneous ground-glass nodule, and part-solid nodule. In addition, we compared the performance of the conventional and novel classifications.Materials and MethodsThe computed tomography images of 41 SSN nodules were interpreted by six observers independently, and the SSN characteristics were classified according to both the conventional and the novel classification systems. Each observer assessed 41 nodules in two different classifications separated by a minimum of 8 weeks. The kappa (κ) coefficient test was used to determine the reliability. The correlation between pulmonary adenocarcinoma spectrum and the SSN classification was analyzed with Spearman correlation coefficients.ResultsInterobserver agreement (κ) was 0.702 (range 0.42–0.89) and 0.707 (range 0.58–0.88) for the conventional and the novel classifications for SSN, respectively, and intraobserver agreement (κ) was 0.92 and 0.88 for the conventional and the novel classifications for SSN, respectively. The novel SSN classification (correlation coefficient range 0.622–0.732) is more strongly correlated with the pathologic invasiveness degree of lesions in adenocarcinoma spectrum than the conventional SSN classification (correlation coefficient range 0.458–0.644).ConclusionsThe agreement between observers on the novel SSN classification system was good and had better correlation with pathologic invasiveness than the conventional SSN classification. Further studies are needed to confirm these results on interobserver agreement.



from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2Fwh9uO

Use of Iodine-131 to Tellurium-132 Ratios for Assessing the Relationships between Human Inhaled Radioactivity and Environmental Monitoring after the Accident in Fukushima.

Use of Iodine-131 to Tellurium-132 Ratios for Assessing the Relationships between Human Inhaled Radioactivity and Environmental Monitoring after the Accident in Fukushima.

Int J Environ Res Public Health. 2018 Mar 09;15(3):

Authors: Uchiyama K, Miyashita M, Tanishima Y, Maeda S, Sato H, Yoshikawa J, Watanabe S, Shibata M, Ohhira S, Kobashi G

Abstract
Significant differences in findings were seen between the intake amounts of iodine-131 that were derived from direct measurements and the estimated intake from environmental monitoring data at the Fukushima accident. To clarify these discrepancies, we have investigated the iodine-131 and tellurium-132 body burdens of five human subjects, who after being exposed to a radioactive plume, underwent 21.5 h whole body counter measurements at Fukui Prefectural Hospital, so clear intake scenario and thyroid counter measurement data were available. To determine the iodine-131 and tellurium-132 body burdens, we introduced a new method of whole body counter calibration composed of a self-consistent approach with the time-dependent correction efficiency factors concept. The ratios of iodine-131 to tellurium-132, ranging from 0.96 ± 0.05 to 2.29 ± 0.38, were consistent with results of the environmental measurements. The 24 h iodine uptake values ranging from 12.1-16.0% were within euthyroid range in Japanese people. These results suggest, even if the relatively low thyroid iodine uptake in the Japanese population was taken into consideration, that there is no doubt about the consistency between direct measurements and environmental monitoring data. Adequate intake scenario is suggested to be principally important to estimate the inhaled radioactivity in areas in or around nuclear accidents.

PMID: 29522502 [PubMed - in process]

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2IgW8WD

A Review of the Current Evidence on Gadolinium Deposition in the Brain

Abstract

Over the past 3 years, gadolinium-based contrast agents have been linked to MRI signal changes in the brain, which have been found to be secondary to gadolinium deposition in the brain, particularly in the dentate nuclei and globus pallidus even in patients having an intact blood-brain barrier and a normal renal function. This tends to occur more in linear agents than with macrocyclic agents. Nonetheless, there has been no significant evidence that this has any clinical consequence. We reviewed the current evidence related to this new phenomenon and the precautionary approach taken by regulatory agencies.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2IfahUk

Comparison of ultrasonography and computed tomography for diagnosing diffuse thyroid disease: a multicenter study

Abstract

Purpose

To compare the diagnostic performance of ultrasonography (US) and computed tomography (CT) for diagnosing incidentally detected diffuse thyroid disease (DTD) in patients who underwent thyroid surgery using multicenter data.

Methods

Between July and December 2016, a total of 177 patients who underwent preoperative thyroid US and neck CT, and subsequent thyroid surgery at 4 participating institutions, were reviewed. US and CT images in each case were retrospectively reviewed by a radiologist at each institution, and classified into one of the following four categories based on US and CT features: no DTD; indeterminate; suspicious for DTD; and DTD. The diagnostic accuracy of US and CT were calculated at each institution by comparison with histopathological results.

Results

Respective US and CT classifications in the 177 patients were no DTD in 75 and 71, indeterminate in 46 and 34, suspicious for DTD in 28 and 31, and DTD in 28 and 41. Among the histopathological results, 113 patients had normal thyroid parenchyma, 23 had Hashimoto thyroiditis, 36 had non-Hashimoto lymphocytic thyroiditis, and 5 had diffuse hyperplasia. The presence of ≥ 2 US and CT features of DTD, which was classified as suspicious for DTD or DTD, had the largest area under the receiver operating characteristic curve (0.866 and 0.893, respectively), with sensitivity and specificity of 71.9 and 91.2% in US, and 84.4 and 84.1% in CT, respectively. However, there was no statistically significant difference between readers' experience and their diagnostic performance.

Conclusion

US and CT imaging may be helpful for detecting incidental DTD.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2tF7PU7

Comparison of cerebral perfusion in perimesencephalic subarachnoid hemorrhage and aneurysmal subarachnoid hemorrhage

Abstract

Purpose

Perimesencephalic hemorrhage (PMH) is a benign subtype of nonaneurysmal subarachnoid hemorrhage (SAH). We aimed to investigate if cerebral perfusion in PMH is less affected than in aneurysmal SAH (aSAH).

Methods

From a prospective cohort of 80 patients with spontaneous SAH, we included PMH patients (n = 15) and selected aSAH patients (n = 39) with similar clinical grade at admission (World Federation of Neurosurgeons Scale-WFNS I/II). Computed tomography (CT) perfusion was performed at < 72 h and/or at 8–10 days. Cerebral perfusion parameter values were compared between groups with nonparametric tests. Subgroup analyses compared PMH and aSAH patients stratified according to aneurysmal location (anterior or posterior circulation) and blood burden (Fisher grade).

Results

At < 72 h, no significant differences in perfusion parameters were found between PMH and aSAH patients. At 8–10 days, PMH patients had lower MTT than aSAH patients, and a trend for higher CBF. PMH patients had higher CBF and CBV at < 72 h when compared to posterior circulation aSAH patients. When compared to aSAH patients with similar blood burden, PMH patients had higher CBF and lower MTT at < 72 h, and lower MTT at 8–10 days.

Conclusion

PMH patients had better cerebral perfusion compared to patients with aSAH, particularly during the vasospasm time window. After stratifying for the amount of blood, PMH patients also had better cerebral perfusion in the first 72 h after SAH. These results are in line with the better clinical presentation and prognosis of PMH, and possibly with a different etiology.

from Imaging via alkiviadis.1961 on Inoreader http://ift.tt/2oZiDHE