Evaluation of Clinical Application and Dosimetric Comparison of Treatment Plans of Gamma Knife and CyberKnife in Treating Arteriovenous Malformations

Purpose: To analyze and compare the characteristics of dose distributions for Leksell Gamma Knife Perfexion (LGK-PFX) and CyberKnife (CK) in treating arteriovenous malformations (AVMs). Subjects and Methods: Twenty-four patients with AVMs who received CK radiosurgery at a prescribed dose (PD) of 16-25 Gy in a single fraction were selected. A LGK-PFX treatment plan with the same PD was designed for each patient. Dosimetric values for both systems were compared with respect to the conformity index (CI); selectivity index (SI); gradient index (GI) of 75, 50, and 25% of the PD; heterogeneity index; volume of the brain tissue covered by doses of 10 and 12 Gy; maximum dose delivered to the brainstem; and beam-on time. Results: The CIs of LGK-PFX and CK were 0.744 ± 0.075 and 0.759 ± 0.071 (p = 0.385), respectively. The SIs of LGK-PFX and CK were 0.764 ± 0.081 and 0.780 ± 0.076 (p = 0.424), respectively. The GI_75%, GI_50%, and GI_25% values of LGK-PFX and CK were 1.028 ± 0.123 and 2.439 ± 0.338 (p p p p Conclusions: LGK-PFX and CK exhibited similar dose conformity. LGK-PFX showed superior normal tissue sparing.
Stereotact Funct Neurosurg 2017;95:142-148

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3 Tesla 23Na Magnetic Resonance Imaging During Acute Kidney Injury

Publication date: Available online 8 May 2017
Source:Academic Radiology
Author(s): Matthias Hammon, Susan Grossmann, Peter Linz, Hannes Seuss, Rebecca Hammon, Daniela Rosenhauer, Rolf Janka, Alexander Cavallaro, Friedrich C. Luft, Jens Titze, Michael Uder, Anke Dahlmann
Rationale and ObjectivesSodium and proton magnetic resonance imaging (²³Na/¹H-MRI) have shown that muscle and skin can store Na⁺ without water. In chronic renal failure and in heart failure, Na⁺ mobilization occurs, but is variable depending on age, dialysis vintage, and other features. Na⁺ storage depots have not been studied in patients with acute kidney injury (AKI).Materials and MethodsWe studied 7 patients with AKI (mean age: 51.7 years; range: 25–84) and 14 age-matched and gender-matched healthy controls. All underwent ²³Na/¹H-MRI at the calf. Patients were studied before and after acute hemodialysis therapy within 5–6 days. The ²³Na-MRI produced grayscale images containing Na⁺ phantoms, which served to quantify Na⁺ contents. A fat-suppressed inversion recovery sequence was used to quantify H2O content.ResultsPlasma Na⁺ levels did not change. Mean Na⁺ contents in muscle and skin did not significantly change following four to five cycles of hemodialysis treatment (before therapy: 32.7 ± 6.9 and 44.2 ± 13.5 mmol/L, respectively; after dialysis: 31.7 ± 10.2 and 42.8 ± 11.8 mmol/L, respectively; P > .05). Water content measurements did not differ significantly before and after hemodialysis in muscle and skin (P > .05). Na⁺ contents in calf muscle and skin of patients before hemodialysis were significantly higher than in healthy subjects (16.6 ± 2.1 and 17.9 ± 3.2) and remained significantly elevated after hemodialysis.ConclusionsNa⁺ in muscle and skin accumulates in patients with AKI and, in contrast to patients receiving chronic hemodialysis and those with acute heart failure, is not mobilized with hemodialysis within 5–6 days.



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Breast Density Legislation in New England

Publication date: Available online 8 May 2017
Source:Academic Radiology
Author(s): Ana P. Lourenco, Roberta M. DiFlorio-Alexander, Priscilla J. Slanetz
Rationale and ObjectivesThis study aimed to assess radiologists' knowledge about breast density legislation as well as perceived practice changes resulting from the enactment of breast density legislation.Materials and MethodsThis is an institutional review board-exempt anonymous email survey of 523 members of the New England Roentgen Ray Society. In addition to radiologist demographics, survey questions addressed radiologist knowledge of breast density legislation, knowledge of breast density as a risk factor for breast cancer, recommendations for supplemental screening, and perceived practice changes resulting from density notification legislation.ResultsOf the 523 members, 96 responded, yielding an 18% response rate. Seventy-three percent of respondents practiced in a state with breast density legislation. Sixty-nine percent felt that breast density notification increased patient anxiety about breast cancer, but also increased patient (74%) and provider (66%) understanding of the effect of breast density on mammographic sensitivity. Radiologist knowledge of the relative risk of breast cancer when comparing breasts of different density was variable.ConclusionsConsiderable confusion and controversy regarding breast density persists, even among practicing radiologists.



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Quantification of Mouse Renal Perfusion Using Arterial Spin Labeled MRI at 1 T

Publication date: Available online 8 May 2017
Source:Academic Radiology
Author(s): Quyen N. Do, Ananth J. Madhuranthakam, Peter Bendel, Robert E. Lenkinski
Rationale and ObjectivesQuantitative measurement of renal perfusion in murine models provides important information on the organ physiology and disease states. The 1-T desktop magnetic resonance imaging has a small footprint and a self-contained fringe field. This resultant flexibility in siting makes the system ideal for preclinical imaging research. Our objective was to evaluate the capability of the 1-T desktop magnetic resonance imaging to measure mouse renal perfusion without the administration of exogenous contrast agents.Materials and MethodsWe implemented a flow-sensitive alternating inversion recovery (FAIR)-based arterial spin labeling sequence with a mouse volume coil on a 1-T desktop magnetic resonance scanner. The validity of the implementation was tested by comparing obtained renal perfusion results with literature values for normal mice and challenging the technique with mice treated with furosemide, a blood vessel vasoconstrictor drug.ResultsThe measured cortical and medullary perfusions were quantified to be 402 ± 95 and 184 ± 52 mL/100 g/min, respectively, in agreement with literature values. The ratio of cortical to medullary renal blood flow was between 2 and 3 and was independent of the mouse weight. As expected, upon furosemide injection, a decrease (~50%) in cortical perfusion was observed in the mice population, at 1 hour post injection compared to baseline (P < 0.0001), which returned to baseline after 24 hours (P = 0.68).ConclusionsWe reported the successful application of FAIR-based arterial spin labeling for noncontrast perfusion measurement of mouse kidneys using a 1-T desktop scanner. The easy implementation of FAIR sequence on a 1-T desktop scanner offers the potential for longitudinal perfusion studies in limited access areas such as behind the barrier in mouse facilities and in multimodality preclinical imaging laboratories without the administration of exogenous contrast agents.



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Maximum Aortic Valve Opening Phase for Annulus Sizing in Pre-TAVR CTA

Publication date: Available online 8 May 2017
Source:Academic Radiology
Author(s): Nam Ju Lee, Saurabh Jha, Bong Ju Lee, Harold Litt
Rationale and ObjectivesThe optimal phase for the measurement of the aortic annular area for transcatheter aortic valve replacement (TAVR) is not standardized, although most agree that systolic measurements are preferred, when the annulus is larger. We hypothesized that the maximum annular area occurs at the cardiac phase of the maximum aortic valve opening (MAVO) and that this phase can be accurately and reproducibly assessed by visual inspection only.Materials and MethodsThe aortic valve opening area was inspected visually by two readers to determine the MAVO phase. The annular area was measured at the MAVO phase and the typical systolic phase (35% of the R-R interval). Differences in the annular area that would change valve sizing for prostheses were noted.ResultsFifty patients (mean age 81) were studied. Ninety percent had the MAVO at the 15%–25% R-R interval. There was high interobserver correlation (0.89) for determining the MAVO phase by visual inspection. For 49 out of 50 patients, the annular area was maximal at the MAVO phase. The mean difference in the annular area between the MAVO phase and 35% was 22.3 (±4.57) mm². In 12% of the patients, the difference in the annular area changed the recommended size of a self-expanding prosthesis and would have altered the procedure in 32% for balloon-expandable prostheses.ConclusionsVisually assessed MAVO occurs in early systole for most patients and is almost always the cardiac phase of the maximal aortic annular area. This method allows rapid and reproducible determination of the appropriate phase for TAVR planning measurements. Consideration should be given to optimizing pre-TAVR computed tomography acquisitions for early systolic reconstruction and visual determination of the MAVO.



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Trabectedin and Campthotecin Synergistically Eliminate Cancer Stem Cells in Cell-of-Origin Sarcoma Models

Publication date: June 2017
Source:Neoplasia, Volume 19, Issue 6
Author(s): Lucia Martinez-Cruzado, Juan Tornin, Aida Rodriguez, Laura Santos, Eva Allonca, Maria Teresa Fernandez-Garcia, Aurora Astudillo, Juana Maria Garcia-Pedrero, Rene Rodriguez
Trabectedin has been approved for second-line treatment of soft tissue sarcomas. However, its efficacy to target sarcoma initiating cells has not been addressed yet. Here, we used pioneer models of myxoid/round cell liposarcoma (MRCLS) and undifferentiated pleomorphic sarcoma (UPS) developed from transformed human mesenchymal stromal/stem cells (MSCs) to evaluate the effect of trabectedin in the cell type responsible for initiating sarcomagenesis and their derived cancer stem cells (CSC) subpopulations. We found that low nanomolar concentrations of trabectedin efficiently inhibited the growth of sarcoma-initiating cells, induced cell cycle arrest, DNA damage and apoptosis. Interestingly, trabectedin treatment repressed the expression of multiple genes responsible for the development of the CSC phenotype, including pluripotency factors, CSC markers and related signaling pathways. Accordingly, trabectedin induced apoptosis and reduced the survival of CSC-enriched tumorsphere cultures with the same efficiency that inhibits the growth of bulk tumor population. In vivo, trabectedin significantly reduced the mitotic index of MRCLS xenografts and inhibited tumor growth at a similar extent to that observed in doxorubicin-treated tumors. Combination of trabectedin with campthotecin (CPT), a chemotherapeutic drug that shows a robust anti-tumor activity when combined with alkylating agents, resulted in a very strong synergistic inhibition of tumor cell growth and highly increased DNA damage and apoptosis induction. Importantly, the enhanced anti-tumor activity of this combination was also observed in CSC subpopulations. These data suggest that trabectedin and CPT combination may constitute a novel strategy to effectively target both the cell-of-origin and CSC subpopulations in sarcoma.



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The effect of ALA-PDT under normoxia and cobalt chloride (CoCl2)-induced hypoxia on adhesion molecules (ICAM-1, VCAM-1) secretion by colorectal cancer cells

Publication date: Available online 8 May 2017
Source:Photodiagnosis and Photodynamic Therapy
Author(s): Aleksandra Kawczyk-Krupka, Zenon Czuba, Beata Kwiatek, Sebastian Kwiatek, Magdalena Krupka, Karolina Sieroń
BACKGROUNDThe most fundamental problem in cancer biology research is to understand the mechanisms of cancer cell resistance to oncological therapies. Literature reports emphasize the important role of adhesion molecules: intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 (ICAM-1 and VCAM-1) in cancer progression and resistance to treatment. Photodynamic therapy (PDT) could become the component of a personalized approach to colorectal cancer, therefore we examined the effects of ALA (δ-aminolevulinic) acid PDT in normoxia and under cobalt chloride (CoCl2)-induced hypoxia on ICAM-1 and VCAM-1 secretion by colorectal cancer cells.METHODSHuman colorectal cancer cells of different malignant potential SW480 and SW620 were used in the experiment. Cell lines were treated ALA, in order to achieve conditions comparable to in vivo hypoxia, CoCl2 was added, then cells were irradiated both in normoxia and in hypoxia-like conditions. Cell viability was assessed using the LDH and MTT assays and apoptosis. ICAM-1 and VCAM-1 concentrations were determined with the Bio − Plex ProTM Assay and System.RESULTSThe experiment revealed that ALA PDT under normoxia and CoCl2-induced hypoxia had no significant effect on ICAM-1 and VCAM-1-dependent adhesion of colorectal cancer cells. The secretion of ICAM-1 by SW480 ell line was more pronounced compared to ICAM-1 secretion by SW620 cells.CONCLUSIONDetermination of tumor marker levels and especially adhesion molecules involved in metastatic spread is necessary. Our experiment reveals, that ALA PDT in normoxia and CoCl2-induced hypoxia has no effect on adhesion molecules secretion by colon cancer cells in vitro.



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