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Sample records for breath-hold cine imaging

  1. Evaluation of a motion artifacts removal approach on breath-hold cine-magnetic resonance images of hypertrophic cardiomyopathy subjects

    NASA Astrophysics Data System (ADS)

    Betancur, Julián.; Simon, Antoine; Schnell, Frédéric; Donal, Erwan; Hernández, Alfredo; Garreau, Mireille

    2013-11-01

    The acquisition of ECG-gated cine magnetic resonance images of the heart is routinely performed in apnea in order to suppress the motion artifacts caused by breathing. However, many factors including the 2D nature of the acquisition and the use of di erent beats to acquire the multiple-view cine images, cause this kind of artifacts to appear. This paper presents the qualitative evaluation of a method aiming to remove motion artifacts in multipleview cine images acquired on patients with hypertrophic cardiomyopathy diagnosis. The approach uses iconic registration to reduce for in-plane artifacts in long-axis-view image stacks and in-plane and out-of-plane motion artifacts in sort-axis-view image stack. Four similarity measures were evaluated: the normalized correlation, the normalized mutual information, the sum of absolute voxel di erences and the Slomka metric proposed by Slomka et al. The qualitative evaluation assessed the misalignment of di erent anatomical structures of the left ventricle as follows: the misalignment of the interventricular septum and the lateral wall for short-axis-view acquisitions and the misalignment between the short-axis-view image and long-axis-view images. Results showed the correction using the normalized correlation as the most appropriated with an 80% of success.

  2. High-resolution breath-hold cardiac magnetic resonance imaging

    SciTech Connect

    Liu, Yu.

    1993-01-01

    This dissertation work is composed of investigations of three methods for fast cardiac magnetic resonance imaging (MRI). These methods include (1) 2D breath-hold magnetization prepared gradient echo and fast spin-echo (FSE) cardiac imaging, (2) 3D breath-hold magnetization prepared gradient echo cardiac imaging, and (3) real-time monitoring, feedback, and triggering for breath-hold MRI. The hypothesis of this work is that high resolution 2D and 3D magnetic resonance data sets for the heart can be acquired with the combination of magnetization prepared blood suppression for gradient echo techniques and accurate breath-holding methods. The 2D method included development of magnetic resonance data acquisition for cardiac imaging. The acquisition time is within a single breath-hold of 16 seconds (assuming heart 60/min). The data acquisition is synchronized with the electrocardiogram signal. Based on consistent observations of specific small cardiac structures like the papillary muscle, trabeculae, moderator band, and coronary vessels in studies of normal volunteers, the image quality represents a significant improvement over that obtained with fast imaging methods previously. To further improve the image quality provided by the 2D method, the first 3D cardiac MRI technique was developed. This method provides even better spatial resolution for cardiac images, with a voxel size of 1.09 [times] 2.19 [times] 4 mm[sup 3]. A 3D acquisition is completed in 8 breath-holds. The data acquisition for 3D cardiac imaging requires a consistent breath-hold position to avoid respiratory artifacts. To improve the reliability of the 3DFT acquisition, a new technique called MR breath-hold feedback was developed to provide reproducible breathholding. The diaphragm location is used as the index for breath-hold reproducibility measurement. The range of the diaphragm displacement in different breath-hold is reduced from 8.3 mm without the technique, to 1.3 mm with the technique.

  3. Comparison of cardiac stroke volume measurement determined using stereological analysis of breath-hold cine MRI and phase contrast velocity mapping.

    PubMed

    Graves, M J; Dommett, D M

    2000-08-01

    Cine MRI of the heart using segmented k-space pulse sequences permits multiphase images to be acquired in a single breath-hold. Whilst image quality is improved compared with conventional (non-segmented) cine imaging, subsequent analysis can be relatively time consuming. In this study, multiple slice breath-hold cine imaging of the heart was performed in 11 normal volunteers. Left and right ventricular stroke volume (SV) was estimated from the images by application of the Cavalieri method of modern design stereology in combination with point counting. The measured SVs were compared with those obtained by cine phase contrast velocity mapping in the ascending aorta and main pulmonary artery. Excellent agreement was found between the SVs determined by the two techniques, with mean differences (+/- one SD) of 0.41 +/- 3.00 ml and 0.41 +/- 4.78 ml for left and right ventricles, respectively. Comparison of left and right ventricular SV using stereology yielded a mean difference of 0.84 +/- 5.70 ml. Breath-hold data acquisition together with stereological analysis is demonstrated to be an accurate and unbiased technique for the rapid assessment of cardiac function. PMID:11026856

  4. Attenuation correction of emission PET images with average CT: Interpolation from breath-hold CT

    NASA Astrophysics Data System (ADS)

    Huang, Tzung-Chi; Zhang, Geoffrey; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Wang, Shyh-Jen; Wu, Tung-Hsin

    2011-05-01

    Misregistration resulting from the difference of temporal resolution in PET and CT scans occur frequently in PET/CT imaging, which causes distortion in tumor quantification in PET. Respiration cine average CT (CACT) for PET attenuation correction has been reported to improve the misalignment effectively by several papers. However, the radiation dose to the patient from a four-dimensional CT scan is relatively high. In this study, we propose a method to interpolate respiratory CT images over a respiratory cycle from inhalation and exhalation breath-hold CT images, and use the average CT from the generated CT set for PET attenuation correction. The radiation dose to the patient is reduced using this method. Six cancer patients of various lesion sites underwent routine free-breath helical CT (HCT), respiration CACT, interpolated average CT (IACT), and 18F-FDG PET. Deformable image registration was used to interpolate the middle phases of a respiratory cycle based on the end-inspiration and end-expiration breath-hold CT scans. The average CT image was calculated from the eight interpolated CT image sets of middle respiratory phases and the two original inspiration and expiration CT images. Then the PET images were reconstructed by these three methods for attenuation correction using HCT, CACT, and IACT. Misalignment of PET image using either CACT or IACT for attenuation correction in PET/CT was improved. The difference in standard uptake value (SUV) from tumor in PET images was most significant between the use of HCT and CACT, while the least significant between the use of CACT and IACT. Besides the similar improvement in tumor quantification compared to the use of CACT, using IACT for PET attenuation correction reduces the radiation dose to the patient.

  5. Magnetic Resonance Imaging in Breath-Hold Divers with Cerebral Decompression Sickness

    PubMed Central

    Matsuo, Ryu; Kamouchi, Masahiro; Arakawa, Shuji; Furuta, Yoshihiko; Kanazawa, Yuka; Kitazono, Takanari

    2014-01-01

    The mechanism of cerebral decompression sickness (DCS) is still unclear. We report 2 cases of breath-hold divers with cerebral DCS in whom magnetic resonance imaging (MRI) demonstrated distinctive characteristics. One case presented right hemiparesthesia, diplopia, and gait disturbance after breath-hold diving into the sea at a depth of 20 m. Brain MRI with fluid-attenuated inversion recovery (FLAIR) sequence revealed multiple hyperintense lesions in the right frontal lobe, bilateral thalamus, pons, and right cerebellar hemisphere. The second case presented visual and gait disturbance after repetitive breath-hold diving into the sea. FLAIR imaging showed hyperintense areas in the bilateral occipito-parietal lobes. In both cases, diffusion-weighted imaging and apparent diffusion coefficient mapping revealed hyperintense areas in the lesions identified by FLAIR. Moreover, follow-up MRI showed attenuation of the FLAIR signal abnormalities. These findings are suggestive of transient hyperpermeability in the microvasculature as a possible cause of cerebral DCS. PMID:24575029

  6. Free-breathing radial volumetric interpolated breath-hold examination vs breath-hold cartesian volumetric interpolated breath-hold examination magnetic resonance imaging of the liver at 1.5T

    PubMed Central

    Yedururi, Sireesha; Kang, HyunSeon C; Wei, Wei; Wagner-Bartak, Nicolaus A; Marcal, Leonardo P; Stafford, R Jason; Willis, Brandy J; Szklaruk, Janio

    2016-01-01

    AIM To compare breath-hold cartesian volumetric interpolated breath-hold examination (cVIBE) and free-breathing radial VIBE (rVIBE) and determine whether rVIBE could replace cVIBE in routine liver magnetic resonance imaging (MRI). METHODS In this prospective study, 15 consecutive patients scheduled for routine MRI of the abdomen underwent pre- and post-contrast breath-hold cVIBE imaging (19 s acquisition time) and free-breathing rVIBE imaging (111 s acquisition time) on a 1.5T Siemens scanner. Three radiologists with 2, 4, and 8 years post-fellowship experience in abdominal imaging evaluated all images. The radiologists were blinded to the sequence types, which were presented in a random order for each patient. For each sequence, the radiologists scored the cVIBE and rVIBE images for liver edge sharpness, hepatic vessel clarity, presence of artifacts, lesion conspicuity, fat saturation, and overall image quality using a five-point scale. RESULTS Compared to rVIBE, cVIBE yielded significantly (P < 0.001) higher scores for liver edge sharpness (mean score, 3.87 vs 3.37), hepatic-vessel clarity (3.71 vs 3.18), artifacts (3.74 vs 3.06), lesion conspicuity (3.81 vs 3.2), and overall image quality (3.91 vs 3.24). cVIBE and rVIBE did not significantly differ in quality of fat saturation (4.12 vs 4.03, P = 0.17). The inter-observer variability with respect to differences between rVIBE and cVIBE scores was close to zero compared to random error and inter-patient variation. Quality of rVIBE images was rated as acceptable for all parameters. CONCLUSION rVIBE cannot replace cVIBE in routine liver MRI. At 1.5T, free-breathing rVIBE yields acceptable, although slightly inferior image quality compared to breath-hold cVIBE. PMID:27551341

  7. SU-E-J-62: Breath Hold for Left-Sided Breast Cancer: Visually Monitored Deep Inspiration Breath Hold Amplitude Evaluated Using Real-Time Position Management

    SciTech Connect

    Conroy, L; Quirk, S; Smith, WL; Yeung, R; Phan, T; Hudson, A

    2015-06-15

    Purpose: We used Real-Time Position Management (RPM) to evaluate breath hold amplitude and variability when gating with a visually monitored deep inspiration breath hold technique (VM-DIBH) with retrospective cine image chest wall position verification. Methods: Ten patients with left-sided breast cancer were treated using VM-DIBH. Respiratory motion was passively collected once weekly using RPM with the marker block positioned at the xiphoid process. Cine images on the tangent medial field were acquired on fractions with RPM monitoring for retrospective verification of chest wall position during breath hold. The amplitude and duration of all breath holds on which treatment beams were delivered were extracted from the RPM traces. Breath hold position coverage was evaluated for symmetric RPM gating windows from ± 1 to 5 mm centered on the average breath hold amplitude of the first measured fraction as a baseline. Results: The average (range) breath hold amplitude and duration was 18 mm (3–36 mm) and 19 s (7–34 s). The average (range) of amplitude standard deviation per patient over all breath holds was 2.7 mm (1.2–5.7 mm). With the largest allowable RPM gating window (± 5 mm), 4 of 10 VM-DIBH patients would have had ≥ 10% of their breath hold positions excluded by RPM. Cine verification of the chest wall position during the medial tangent field showed that the chest wall was greater than 5 mm from the baseline in only 1 out of 4 excluded patients. Cine images verify the chest wall/breast position only, whether this variation is acceptable in terms of heart sparing is a subject of future investigation. Conclusion: VM-DIBH allows for greater breath hold amplitude variability than using a 5 mm gating window with RPM, while maintaining chest wall positioning accuracy within 5 mm for the majority of patients.

  8. Breath holding spell

    MedlinePlus

    ... confronted Breath holding spells are more common in children with: Genetic conditions, such as Riley-Day syndrome or Rett syndrome Iron deficiency anemia A family history of breath holding spells (parents ...

  9. Clinical Results of Image-Guided Deep Inspiration Breath Hold Breast Irradiation

    SciTech Connect

    Borst, Gerben R.; Sonke, Jan-Jakob; Hollander, Suzanne den; Betgen, Anja; Remeijer, Peter; Giersbergen, Aline van; Russell, Nicola S.; Elkhuizen, Paula H.M.; Bartelink, Harry; Vliet-Vroegindeweij, Corine van

    2010-12-01

    Purpose: To evaluate the feasibility, cardiac dose reduction, and the influence of the setup error on the delivered dose for fluoroscopy-guided deep inspiration breath hold (DIBH) irradiation using a cone-beam CT for irradiation of left-sided breast cancer patients. Methods and Materials: Nineteen patients treated according to the DIBH protocol were evaluated regarding dose to the ipsilateral breast (or thoracic wall), heart, (left ventricle [LV]and left anterior descending artery [LAD]), and lung. The DIBH treatment plan was compared to the free-breathing (FB) treatment planning and to the dose data in which setup error was taken into account (i.e., actual delivered dose). Results: The largest setup variability was observed in the direction perpendicular to the RT field ({mu} = -0.8 mm, {Sigma} = 2.9 mm, {sigma} = 2.0 mm). The mean (D{sub mean}) and maximum (D{sub max}) doses of the DIBH treatment plan was significantly lower compared with the FB treatment plan for the heart (34% and 25%, p < 0.001), LV (71% and 28%, p < 0.001), and LAD (52% and 39.8%, p < 0.001). For some patients, large differences were observed between the heart D{sub max} according to the DIBH treatment plan and the actual delivered dose (up to 71%), although D{sub max} was always smaller than the planned FB dose (mean group reduction = 29%, p < 0.001). Conclusion: The image-guided DIBH treatment protocol is a feasible irradiation method with small setup variability that significantly reduces the dose to the heart, LV, and LAD.

  10. Incorporating breath holding and image guidance in the adjuvant gastric cancer radiotherapy: a dosimetric study

    PubMed Central

    2012-01-01

    Background The respiratory related target motion and setup error will lead to a large margin in the gastric radiotherapy. The purpose of this study is to investigate the dosimetric benefit and the possibility of incorporating the breath-hold (BH) technique with online image-guided radiotherapy in the adjuvant gastric cancer radiotherapy. Methods Setup errors and target motions of 22 post-operative gastric cancer patients with surgical clips were analyzed. Clips movement was recorded using the digital fluoroscopics and the probability distribution functions (pdf) of the target motions were created for both the free breathing (FB) and BH treatment. For dosimetric comparisons, two intensity-modulated radiotherapy (IMRT) treatment plans, i.e. the free breathing treatment plan (IMRTFB) and the image-guided BH treatment plan (IMRTIGBH) using the same beam parameters were performed among 6 randomly selected patients. Different margins for FB and BH plans were derived. The plan dose map was convoluted with various pdfs of the setup errors and the target motions. Target coverage and dose to organs at risk were compared and the dose-escalation probability was assessed. Results The mean setup errors were 1.2 mm in the superior-inferior (SI), 0.0 mm in the left-right (LR), and 1.4 mm in the anterior-posterior (AP) directions. The mean target motion for the free breathing (vs. BH) was 11.1 mm (vs. 2.2 mm), 1.9 mm (vs. 1.1 mm), and 5.5 mm (vs. 1.7 mm) in the SI, LR, and AP direction, respectively. The target coverage was comparable for all the original plans. IMRTIGBH showed lower dose to the liver compared with IMRTFB (p = 0.01) but no significant difference in the kidneys. Convolved IMRTIGBH showed better sparing in kidneys (p < 0.01) and similar in liver (p = 0.08). Conclusions Combining BH technique with online image guided IMRT can minimize the organ motion and improve the setup accuracy. The dosimetric comparison showed the dose could be

  11. Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

    PubMed Central

    Chan, Queenie; Wáng, Yì-Xiáng J.

    2016-01-01

    Background Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion. Methods A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms. Results Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression. Conclusions A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods. PMID:27190769

  12. Comparison between in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging

    SciTech Connect

    Rofsky, N.M.; Weinreb, J.C.; Ambrosino, M.M.; Safir, J.; Krinsky, G.

    1996-03-01

    Our goal was to compare in-phase (IP) and opposed-phase (OP) sequences for GRE breath-hold hepatic imaging. Non-contrast-enhanced IP and OP GRE breath-hold images were obtained in 104 consecutive patients referred for abdominal MRI at 1.0 T. For both sequences, the TR, FA, matrix, FOV, slice thickness, interslice gap, and measurements were kept constant. Images were compared quantitatively [liver/spleen and liver/lesion signal difference/noise ratio, (SD/N)] and qualitatively (artifacts, lesion detection and conspicuity, and intrahepatic anatomy). There was no statistically significant difference when comparing IP and OP sequences for liver/spleen and liver/lesion SD/N or for the qualitative parameters. In patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SD/N (0.9 and - 1.2, respectively) than the IP sequences (20 and 17, respectively). Furthermore, in several cases with fatty infiltration, many more lesions were identified using IP images. The use of IP and OP GRE sequences provides complementary diagnostic information. Focal liver lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging. 11 refs., 3 figs., 1 tab.

  13. Clinical outcome of hypofractionated breath-hold image-guided SABR of primary lung tumors and lung metastases

    PubMed Central

    2014-01-01

    Background Stereotactic Ablative RadioTherapy (SABR) of lung tumors/metastases has been shown to be an effective treatment modality with low toxicity. Outcome and toxicity were retrospectively evaluated in a unique single-institution cohort treated with intensity-modulated image-guided breath-hold SABR (igSABR) without external immobilization. The dose–response relationship is analyzed based on Biologically Equivalent Dose (BED). Patients and methods 50 lesions in 43 patients with primary NSCLC (n = 27) or lung-metastases of various primaries (n = 16) were consecutively treated with igSABR with Active-Breathing-Coordinator (ABC®) and repeat-breath-hold cone-beam-CT. After an initial dose-finding/-escalation period, 5x12 Gy for peripheral lesions and single doses of 5 Gy to varying dose levels for central lesions were applied. Overall-survival (OS), progression-free-survival (PFS), progression pattern, local control (LC) and toxicity were analyzed. Results The median BED2 was 83 Gy. 12 lesions were treated with a BED2 of <80 Gy, and 38 lesions with a BED2 of >80 Gy. Median follow-up was 15 months. Actuarial 1- and 2-year OS were 67% and 43%; respectively. Cause of death was non-disease-related in 27%. Actuarial 1- and 2-year PFS was 42% and 28%. Progression site was predominantly distant. Actuarial 1- and 2 year LC was 90% and 85%. LC showed a trend for a correlation to BED2 (p = 0.1167). Pneumonitis requiring conservative treatment occurred in 23%. Conclusion Intensity-modulated breath-hold igSABR results in high LC-rates and low toxicity in this unfavorable patient cohort with inoperable lung tumors or metastases. A BED2 of <80 Gy was associated with reduced local control. PMID:24401323

  14. Breath-Holding Spells

    MedlinePlus

    ... less than a minute before a child regains consciousness and resumes breathing normally. Breath-holding spells can ... spells cause kids to stop breathing and lose consciousness for up to a minute. In the most ...

  15. Single Breath-Hold Physiotherapy Technique: Effective tool for T2* magnetic resonance imaging in young patients with thalassaemia major.

    PubMed

    Mevada, Surekha T; Al-Mahruqi, Najma; El-Beshlawi, Ismail; El-Shinawy, Mohamed; Zachariah, Mathew; Al-Rawas, Abdul H; Daar, Shahina; Wali, Yasser

    2016-02-01

    Magnetic resonance imaging using T2* (MRI T2*) is a highly sensitive and non-invasive technique for the detection of tissue iron load. Although the single breath-hold multi-echo T2* technique has been available at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, since 2006, it could not be performed on younger patients due to their inability to hold their breath after expiration. This study was carried out between May 2007 and May 2015 and assessed 50 SQUH thalassaemic patients aged 7-17 years old. Seven of these patients underwent baseline and one-year follow-up MRI T2* scans before receiving physiotherapy training. Subsequently, all patients were trained by a physiotherapist to hold their breath for approximately 15-20 seconds at the end of expiration before undergoing baseline and one-year follow-up MRI T2* scans. Failure rates for the pre- and post-training groups were 6.0% and 42.8%, respectively. These results indicate that the training of thalassaemic patients in breath-hold techniques is beneficial and increases rates of compliance for MRI T2* scans. PMID:26909218

  16. Accuracy Evaluation of a 3-Dimensional Surface Imaging System for Guidance in Deep-Inspiration Breath-Hold Radiation Therapy

    SciTech Connect

    Alderliesten, Tanja; Sonke, Jan-Jakob; Betgen, Anja; Honnef, Joeri; Vliet-Vroegindeweij, Corine van; Remeijer, Peter

    2013-02-01

    Purpose: To investigate the applicability of 3-dimensional (3D) surface imaging for image guidance in deep-inspiration breath-hold radiation therapy (DIBH-RT) for patients with left-sided breast cancer. For this purpose, setup data based on captured 3D surfaces was compared with setup data based on cone beam computed tomography (CBCT). Methods and Materials: Twenty patients treated with DIBH-RT after breast-conserving surgery (BCS) were included. Before the start of treatment, each patient underwent a breath-hold CT scan for planning purposes. During treatment, dose delivery was preceded by setup verification using CBCT of the left breast. 3D surfaces were captured by a surface imaging system concurrently with the CBCT scan. Retrospectively, surface registrations were performed for CBCT to CT and for a captured 3D surface to CT. The resulting setup errors were compared with linear regression analysis. For the differences between setup errors, group mean, systematic error, random error, and 95% limits of agreement were calculated. Furthermore, receiver operating characteristic (ROC) analysis was performed. Results: Good correlation between setup errors was found: R{sup 2}=0.70, 0.90, 0.82 in left-right, craniocaudal, and anterior-posterior directions, respectively. Systematic errors were {<=}0.17 cm in all directions. Random errors were {<=}0.15 cm. The limits of agreement were -0.34-0.48, -0.42-0.39, and -0.52-0.23 cm in left-right, craniocaudal, and anterior-posterior directions, respectively. ROC analysis showed that a threshold between 0.4 and 0.8 cm corresponds to promising true positive rates (0.78-0.95) and false positive rates (0.12-0.28). Conclusions: The results support the application of 3D surface imaging for image guidance in DIBH-RT after BCS.

  17. Simulation of four-dimensional CT images from deformable registration between inhale and exhale breath-hold CT scans

    SciTech Connect

    Sarrut, David; Boldea, Vlad; Miguet, Serge; Ginestet, Chantal

    2006-03-15

    Purpose: We propose to simulate an artificial four-dimensional (4-D) CT image of the thorax during breathing. It is performed by deformable registration of two CT scans acquired at inhale and exhale breath-hold. Materials and methods: Breath-hold images were acquired with the ABC (Active Breathing Coordinator) system. Dense deformable registrations were performed. The method was a minimization of the sum of squared differences (SSD) using an approximated second-order gradient. Gaussian and linear-elastic vector field regularizations were compared. A new preprocessing step, called a priori lung density modification (APLDM), was proposed to take into account lung density changes due to inspiration. It consisted of modulating the lung densities in one image according to the densities in the other, in order to make them comparable. Simulated 4-D images were then built by vector field interpolation and image resampling of the two initial CT images. A variation in the lung density was taken into account to generate intermediate artificial CT images. The Jacobian of the deformation was used to compute voxel values in Hounsfield units. The accuracy of the deformable registration was assessed by the spatial correspondence of anatomic landmarks located by experts. Results: APLDM produced statistically significantly better results than the reference method (registration without APLDM preprocessing). The mean (and standard deviation) of distances between automatically found landmark positions and landmarks set by experts were 2.7(1.1) mm with APLDM, and 6.3(3.8) mm without. Interexpert variability was 2.3(1.2) mm. The differences between Gaussian and linear elastic regularizations were not statistically significant. In the second experiment using 4-D images, the mean difference between automatic and manual landmark positions for intermediate CT images was 2.6(2.0) mm. Conclusion: The generation of 4-D CT images by deformable registration of inhale and exhale CT images is

  18. SU-E-J-223: A BOLD Contrast Imaging Sequence to Evaluate Oxygenation Changes Due to Breath Holding for Breast Radiotherapy: A Pilot Study

    SciTech Connect

    Adamson, J; Chang, Z; Cai, J; Palta, M; Horton, J; Yin, F; Blitzblau, R

    2015-06-15

    Purpose: To develop a robust MRI sequence to measure BOLD breath hold induced contrast in context of breast radiotherapy. Methods: Two sequences were selected from prior studies as candidates to measure BOLD contrast attributable to breath holding within the breast: (1) T2* based Gradient Echo EPI (TR/TE = 500/41ms, flip angle = 60°), and (2) T2 based Single Shot Fast Spin Echo (SSFSE) (TR/TE = 3000/60ms). We enrolled ten women post-lumpectomy for breast cancer who were undergoing treatment planning for whole breast radiotherapy. Each session utilized a 1.5T GE MRI and 4 channel breast coil with the subject immobilized prone on a custom board. For each sequence, 1–3 planes of the lumpectomy breast were imaged continuously during a background measurement (1min) and intermittent breath holds (20–40s per breath hold, 3–5 holds per sequence). BOLD contrast was quantified as correlation of changes in per-pixel intensity with the breath hold schedule convolved with a hemodynamic response function. Subtle motion was corrected using a deformable registration algorithm. Correlation with breath-holding was considered significant if p<0.001. Results: The percentage of the breast ROI with positive BOLD contrast measured by the two sequences were in agreement with a correlation coefficient of R=0.72 (p=0.02). While both sequences demonstrated areas with strong BOLD response, the response was more systematic throughout the breast for the SSFSE (T2) sequence (% breast with response in the same direction: 51.2%±0.7% for T2* vs. 68.1%±16% for T2). In addition, the T2 sequence was less prone to magnetic susceptibility artifacts, especially in presence of seroma, and provided a more robust image with little distortion or artifacts. Conclusion: A T2 SSFSE sequence shows promise for measuring BOLD contrast in the context of breast radiotherapy utilizing a breath hold technique. Further study in a larger patient cohort is warranted to better refine this novel technique.

  19. A Voluntary Breath-Hold Treatment Technique for the Left Breast With Unfavorable Cardiac Anatomy Using Surface Imaging

    SciTech Connect

    Gierga, David P.; Turcotte, Julie C.; Sharp, Gregory C.; Harvard Medical School, Boston, Massachusetts ; Sedlacek, Daniel E.; Cotter, Christopher R.; Taghian, Alphonse G.; Harvard Medical School, Boston, Massachusetts

    2012-12-01

    Purpose: Breath-hold (BH) treatments can be used to reduce cardiac dose for patients with left-sided breast cancer and unfavorable cardiac anatomy. A surface imaging technique was developed for accurate patient setup and reproducible real-time BH positioning. Methods and Materials: Three-dimensional surface images were obtained for 20 patients. Surface imaging was used to correct the daily setup for each patient. Initial setup data were recorded for 443 fractions and were analyzed to assess random and systematic errors. Real time monitoring was used to verify surface placement during BH. The radiation beam was not turned on if the BH position difference was greater than 5 mm. Real-time surface data were analyzed for 2398 BHs and 363 treatment fractions. The mean and maximum differences were calculated. The percentage of BHs greater than tolerance was calculated. Results: The mean shifts for initial patient setup were 2.0 mm, 1.2 mm, and 0.3 mm in the vertical, longitudinal, and lateral directions, respectively. The mean 3-dimensional vector shift was 7.8 mm. Random and systematic errors were less than 4 mm. Real-time surface monitoring data indicated that 22% of the BHs were outside the 5-mm tolerance (range, 7%-41%), and there was a correlation with breast volume. The mean difference between the treated and reference BH positions was 2 mm in each direction. For out-of-tolerance BHs, the average difference in the BH position was 6.3 mm, and the average maximum difference was 8.8 mm. Conclusions: Daily real-time surface imaging ensures accurate and reproducible positioning for BH treatment of left-sided breast cancer patients with unfavorable cardiac anatomy.

  20. Diagnosing Lung Nodules on Oncologic MR/PET Imaging: Comparison of Fast T1-Weighted Sequences and Influence of Image Acquisition in Inspiration and Expiration Breath-Hold

    PubMed Central

    Schwenzer, Nina F.; Seith, Ferdinand; Gatidis, Sergios; Brendle, Cornelia; Schmidt, Holger; Pfannenberg, Christina A.; laFougère, Christian; Nikolaou, Konstantin

    2016-01-01

    Objective First, to investigate the diagnostic performance of fast T1-weighted sequences for lung nodule evaluation in oncologic magnetic resonance (MR)/positron emission tomography (PET). Second, to evaluate the influence of image acquisition in inspiration and expiration breath-hold on diagnostic performance. Materials and Methods The study was approved by the local Institutional Review Board. PET/CT and MR/PET of 44 cancer patients were evaluated by 2 readers. PET/CT included lung computed tomography (CT) scans in inspiration and expiration (CTin, CTex). MR/PET included Dixon sequence for attenuation correction and fast T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences (volume interpolated breath-hold examination acquired in inspiration [VIBEin], volume interpolated breath-hold examination acquired in expiration [VIBEex]). Diagnostic performance was analyzed for lesion-, lobe-, and size-dependence. Diagnostic confidence was evaluated (4-point Likert-scale; 1 = high). Jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed. Results Seventy-six pulmonary lesions were evaluated. Lesion-based detection rates were: CTex, 77.6%; VIBEin, 53.3%; VIBEex, 51.3%; and Dixon, 22.4%. Lobe-based detection rates were: CTex, 89.6%; VIBEin, 58.3%; VIBEex, 60.4%; and Dixon, 31.3%. In contrast to CT, inspiration versus expiration did not alter diagnostic performance in VIBE sequences. Diagnostic confidence was best for VIBEin and CTex and decreased in VIBEex and Dixon (1.2 ± 0.6; 1.2 ± 0.7; 1.5 ± 0.9; 1.7 ± 1.1, respectively). The JAFROC figure-of-merit of Dixon was significantly lower. All patients with malignant lesions were identified by CTex, VIBEin, and VIBEex, while 3 patients were false-negative in Dixon. Conclusion Fast T1-weighted VIBE sequences allow for identification of patients with malignant pulmonary lesions. The Dixon sequence is not recommended for lung nodule evaluation in oncologic MR

  1. [An Examination of Variable Image Positions in the Aortic Valve Blood Flow Using Phase Contrast MRI: Effect of Breath-holding Methods in Healthy Volunteers].

    PubMed

    Nakagawa, Kenichi; Morimoto, Noriyoshi; Fukushima, Sachi

    2015-12-01

    Phase contrast MRI (PC-MRI) is a useful tool for evaluating valvular pathology. In addition, PC-MRI can provide a noninvasive assessment of blood flow in an arbitrary cross section. However, the blood flow measurement with breath-hold or free breath PC-MRI may be different from each other because of intrathoracic pressure changing and variable image position. The aim of this study was to find both the optimal breath-hold technique and the image position. Quantitative flow images were acquired in four planes (ascending aorta: Ao, sino-tubular junction: STJ, valsalva sinus: valsalva, left ventricular outflow tract: LVOT), in healthy subjects (n=10). The study protocol was divided into two parts: (1) stroke volume (SV) measured in each slice positions by using inspiration, expiration, and navigation method during normal breathing and (2) SV measured at each breath-hold techniques in the Ao, STJ, valsalva, and LVOT. As a result, (1) SV of the respective measurement positions were not significant by using inspiration, expiration, and navigation method and (2) LVOT SV was significantly lower than Ao, STJ, and valsalva. PMID:26685835

  2. In vivo micro-CT imaging of the murine lung via a computer controlled intermittent iso-pressure breath hold (IIBH) technique

    NASA Astrophysics Data System (ADS)

    Namati, Eman; Chon, Deokiee; Thiesse, Jacqueline; McLennan, Geoffrey; Sieren, Jered; Ross, Alan; Hoffman, Eric A.

    2006-03-01

    Micro-CT, a technique for imaging small objects at high resolution using micro focused x-rays, is becoming widely available for small animal imaging. With the growing number of mouse models of pulmonary pathology, there is great interest in following disease progression and evaluating the alteration in longitudinal studies. Along with the high resolution associated with micro CT comes increased scanning times, and hence minimization of motion artifacts is required. We propose a new technique for imaging mouse lungs in vivo by inducing an intermittent iso-pressure breath hold (IIBH) with a fixed level of positive airway pressure during image acquisition, to decrease motion artifacts and increase image resolution and quality. Mechanical ventilation of the respiratory system for such a setup consists of three phases, 1) tidal breathing (hyperventilated), 2) a breath hold during a fixed level of applied positive airway pressure, 3) periodic deep sighs. Image acquisition is triggered over the stable segment of the IIBH period. Comparison of images acquired from the same mouse lung using three imaging techniques (normal breathing / no gating, normal breathing with gating at End Inspiration (EI) and finally the IIBH technique) demonstrated substantial improvements in resolution and quality when using the IIBH gating. Using IIBH triggering the total image acquisition time increased from 15 minutes to 35 minutes, although total x-ray exposure time and hence animal dosage remains the same. This technique is an important step in providing high quality lung imaging of the mouse in vivo, and will provide a good foundation for future longitudinal studies.

  3. Functional Analysis and Intervention for Breath Holding.

    ERIC Educational Resources Information Center

    Kern, Lee; And Others

    1995-01-01

    A functional analysis of breath-holding episodes in a 7-year-old girl with severe mental retardation and Cornelia-de-Lange syndrome indicated that breath holding served an operant function, primarily to gain access to attention. Use of extinction, scheduled attention, and a picture card communication system decreased breath holding. (Author/SW)

  4. Evaluation of target and cardiac position during visually monitored deep inspiration breath-hold for breast radiotherapy.

    PubMed

    Conroy, Leigh; Yeung, Rosanna; Watt, Elizabeth; Quirk, Sarah; Long, Karen; Hudson, Alana; Phan, Tien; Smith, Wendy L

    2016-01-01

    A low-resource visually monitored deep inspiration breath-hold (VM-DIBH) technique was successfully implemented in our clinic to reduce cardiac dose in left-sided breast radiotherapy. In this study, we retrospectively characterized the chest wall and heart positioning accuracy of VM-DIBH using cine portal images from 42 patients. Central chest wall position from field edge and in-field maximum heart distance (MHD) were manually measured on cine images and compared to the planned positions based on the digitally reconstructed radiographs (DRRs). An in-house program was designed to measure left anterior descending artery (LAD) and chest wall separation on the planning DIBH CT scan with respect to breath-hold level (BHL) during simulation to determine a minimum BHL for VM-DIBH eligibility. Systematic and random setup uncertainties of 3.0 mm and 2.6 mm, respectively, were found for VM-DIBH treatment from the chest wall measurements. Intrabeam breath-hold stability was found to be good, with over 96% of delivered fields within 3 mm. Average treatment MHD was significantly larger for those patients where some of the heart was planned in the field compared to patients whose heart was completely shielded in the plan (p < 0.001). No evidence for a minimum BHL was found, suggesting that all patients who can tolerate DIBH may yield a benefit from it. PMID:27455494

  5. SU-E-J-55: End-To-End Effectiveness Analysis of 3D Surface Image Guided Voluntary Breath-Holding Radiotherapy for Left Breast

    SciTech Connect

    Lin, M; Feigenberg, S

    2015-06-15

    Purpose To evaluate the effectiveness of using 3D-surface-image to guide breath-holding (BH) left-side breast treatment. Methods Two 3D surface image guided BH procedures were implemented and evaluated: normal-BH, taking BH at a comfortable level, and deep-inspiration-breath-holding (DIBH). A total of 20 patients (10 Normal-BH and 10 DIBH) were recruited. Patients received a BH evaluation using a commercialized 3D-surface- tracking-system (VisionRT, London, UK) to quantify the reproducibility of BH positions prior to CT scan. Tangential 3D/IMRT plans were conducted. Patients were initially setup under free-breathing (FB) condition using the FB surface obtained from the untaged CT to ensure a correct patient position. Patients were then guided to reach the planned BH position using the BH surface obtained from the BH CT. Action-levels were set at each phase of treatment process based on the information provided by the 3D-surface-tracking-system for proper interventions (eliminate/re-setup/ re-coaching). We reviewed the frequency of interventions to evaluate its effectiveness. The FB-CBCT and port-film were utilized to evaluate the accuracy of 3D-surface-guided setups. Results 25% of BH candidates with BH positioning uncertainty > 2mm are eliminated prior to CT scan. For >90% of fractions, based on the setup deltas from3D-surface-trackingsystem, adjustments of patient setup are needed after the initial-setup using laser. 3D-surface-guided-setup accuracy is comparable as CBCT. For the BH guidance, frequency of interventions (a re-coaching/re-setup) is 40%(Normal-BH)/91%(DIBH) of treatments for the first 5-fractions and then drops to 16%(Normal-BH)/46%(DIBH). The necessity of re-setup is highly patient-specific for Normal-BH but highly random among patients for DIBH. Overall, a −0.8±2.4 mm accuracy of the anterior pericardial shadow position was achieved. Conclusion 3D-surface-image technology provides effective intervention to the treatment process and ensures

  6. Accelerated Cardiac T2 Mapping using Breath-hold Multi-Echo Fast Spin-Echo Pulse Sequence with Compressed sensing and Parallel Imaging

    PubMed Central

    Feng, Li; Otazo, Ricardo; Jung, Hong; Jensen, Jens H.; Ye, Jong C.; Sodickson, Daniel K.; Kim, Daniel

    2010-01-01

    Cardiac T2 mapping is a promising method for quantitative assessment of myocardial edema and iron overload. We have developed a new multi-echo fast spin echo (ME-FSE) pulse sequence for breath-hold T2 mapping with acceptable spatial resolution. We propose to further accelerate this new ME-FSE pulse sequence using k-t FOCal Underdetermined System Solver (FOCUSS) adapted with a framework that utilizes both compressed sensing and parallel imaging (.e.g, GRAPPA) to achieve higher spatial resolution. We imaged twelve control subjects in mid-ventricular short-axis planes and compared the accuracy of T2 measurements obtained using ME-FSE with GRAPPA and ME-FSE with k-t FOCUSS. For image reconstruction, we used a bootstrapping two-step approach, where in the first step fast Fourier transform was used as the sparsifying transform and in the final step principal component analysis was used as the sparsifying transform. Compared with T2 measurements obtained using GRAPPA, T2 measurements obtained using k-t FOCUSS were in excellent agreement (mean difference = 0.04 ms; upper/lower 95% limits of agreement were 2.26/−2.19 ms). The proposed accelerated ME-FSE pulse sequence with k-t FOCUSS is a promising investigational method for rapid T2 measurement of the heart with relatively high spatial resolution (1.7 mm × 1.7 mm). PMID:21360737

  7. Using surface imaging and visual coaching to improve the reproducibility and stability of deep-inspiration breath hold for left-breast-cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Cerviño, Laura I.; Gupta, Sonia; Rose, Mary A.; Yashar, Catheryn; Jiang, Steve B.

    2009-11-01

    Late cardiac complications may arise after left-breast radiation therapy. Deep-inspiration breath hold (DIBH) allows reduction of the irradiated heart volume at the same time as it reduces tumor bed motion and increases lung sparing. In the present study, we have evaluated the improvement in reproducibility and stability of the DIBH for left-breast-cancer treatment when visual coaching is provided with the aid of 3D video surface imaging and video goggles. Five left-breast-cancer patients and fifteen healthy volunteers were asked to perform a series of DIBHs without and with visual coaching. Reproducibility and stability of DIBH were measured for each individual with and without visual coaching. The average reproducibility and stability changed from 2.1 mm and 1.5 mm, respectively, without visual feedback to 0.5 mm and 0.7 mm with visual feedback, showing a significant statistical difference (p < 0.001 for reproducibility, p < 0.01 for stability). Significant changes (>2 mm) in reproducibility and stability were observed in 35% and 15% of the subjects, respectively. The average chest wall excursion of the DIBH with respect to the free breathing preceding the DIBH was found to be 11.3 mm. The reproducibility and stability of the DIBH improve significantly from the visual coaching provided to the patient, especially in those patients with poor reproducibility and stability.

  8. Single Breath-Hold Physiotherapy Technique

    PubMed Central

    Mevada, Surekha T.; Al-Mahruqi, Najma; El-Beshlawi, Ismail; El-Shinawy, Mohamed; Zachariah, Mathew; Al-Rawas, Abdul H.; Daar, Shahina; Wali, Yasser

    2016-01-01

    Magnetic resonance imaging using T2* (MRI T2*) is a highly sensitive and non-invasive technique for the detection of tissue iron load. Although the single breath-hold multi-echo T2* technique has been available at the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, since 2006, it could not be performed on younger patients due to their inability to hold their breath after expiration. This study was carried out between May 2007 and May 2015 and assessed 50 SQUH thalassaemic patients aged 7–17 years old. Seven of these patients underwent baseline and one-year follow-up MRI T2* scans before receiving physiotherapy training. Subsequently, all patients were trained by a physiotherapist to hold their breath for approximately 15–20 seconds at the end of expiration before undergoing baseline and one-year follow-up MRI T2* scans. Failure rates for the pre- and post-training groups were 6.0% and 42.8%, respectively. These results indicate that the training of thalassaemic patients in breath-hold techniques is beneficial and increases rates of compliance for MRI T2* scans. PMID:26909218

  9. Tracheomalacia and breath holding: a case report.

    PubMed

    Griffiths, H; Doull, I; Williams, R G; Marnane, C

    2000-10-01

    A child with a long standing history of cyanotic breath holding attacks presented with acute respiratory distress. Subsequent investigation established that her clinical condition was caused by tracheomalacia. We hypothesise that tracheomalacia might be an under recognised contributor to cyanotic breath holding attacks, the pathogenesis of which is poorly understood. PMID:10999873

  10. Repetitive breath-hold diving causes serious brain injury.

    PubMed

    Tamaki, Hideki; Kohshi, Kiyotaka; Sajima, Shuichi; Takeyama, Junichiro; Nakamura, Takashi; Ando, Hideo; Ishitake, Tatsuya

    2010-01-01

    We report on a Japanese male professional breath-hold diver (Ama) who developed neurological disorders during repetitive dives to 22 meters of sea water. Each diving duration and surface interval were 40-80 seconds and 20-30 seconds, respectively. He suffered from sensory numbness of the right cheek, hand and foot, and double vision after more than two hours of consecutive dives. Magnetic resonance images of his brain showed multiple cerebral infarcts, and one of the lesions was situated in the brainstem. There is a possibility that repetitive deep breath-hold dives with short surface intervals can induce fatal accidents for divers. PMID:20369648

  11. Cardiac dosimetric evaluation of deep inspiration breath-hold level variances using computed tomography scans generated from deformable image registration displacement vectors.

    PubMed

    Harry, Taylor; Rahn, Doug; Semenov, Denis; Gu, Xuejun; Yashar, Catheryn; Einck, John; Jiang, Steve; Cerviño, Laura

    2016-01-01

    There is a reduction in cardiac dose for left-sided breast radiotherapy during treatment with deep inspiration breath-hold (DIBH) when compared with treatment with free breathing (FB). Various levels of DIBH may occur for different treatment fractions. Dosimetric effects due to this and other motions are a major component of uncertainty in radiotherapy in this setting. Recent developments in deformable registration techniques allow displacement vectors between various temporal and spatial patient representations to be digitally quantified. We propose a method to evaluate the dosimetric effect to the heart from variable reproducibility of DIBH by using deformable registration to create new anatomical computed tomography (CT) scans. From deformable registration, 3-dimensional deformation vectors are generated with FB and DIBH. The obtained deformation vectors are scaled to 75%, 90%, and 110% and are applied to the reference image to create new CT scans at these inspirational levels. The scans are then imported into the treatment planning system and dose calculations are performed. The average mean dose to the heart was 2.5Gy (0.7 to 9.6Gy) at FB, 1.2Gy (0.6 to 3.8Gy, p < 0.001) at 75% inspiration, 1.1Gy (0.6 to 3.1Gy, p = 0.004) at 90% inspiration, 1.0Gy (0.6 to 3.0Gy) at 100% inspiration or DIBH, and 1.0Gy (0.6 to 2.8Gy, p = 0.019) at 110% inspiration. The average mean dose to the left anterior descending artery (LAD) was 19.9Gy (2.4 to 46.4Gy), 8.6Gy (2.0 to 43.8Gy, p < 0.001), 7.2Gy (1.9 to 40.1Gy, p = 0.035), 6.5Gy (1.8 to 34.7Gy), and 5.3Gy (1.5 to 31.5Gy, p < 0.001), correspondingly. This novel method enables numerous anatomical situations to be mimicked and quantifies the dosimetric effect they have on a treatment plan. PMID:26206154

  12. A clinical evaluation of visual feedback-guided breath-hold reproducibility of tumor location

    NASA Astrophysics Data System (ADS)

    Yoshitake, Tadamasa; Shioyama, Yoshiyuki; Nakamura, Katsumasa; Ohga, Saiji; Nonoshita, Takeshi; Ohnishi, Kayoko; Terashima, Kotaro; Arimura, Hidetaka; Hirata, Hideki; Honda, Hiroshi

    2009-12-01

    The purpose of this study was to evaluate the reproducibility of visual feedback-guided breath-hold using a machine vision system with a charge-coupled device camera and a monocular head-mounted display. Sixteen patients with lung tumors who were treated with stereotactic radiotherapy were enrolled. A machine vision system with a charge-coupled device camera was used for monitoring respiration. A monocular head-mounted display was used to provide the patient with visual feedback about the breathing trace. The patients could control their breathing so that the breathing waveform would fall between the upper and lower threshold lines. Planning and treatment were performed under visual feedback-guided expiratory breath-hold. Electronic portal images were obtained during treatment. The range of cranial-caudal motion of the tumor location during each single breath-hold was calculated as the intra-breath-hold (intra-BH) variability. The maximum displacement between the two to five averaged tumor locations of each single breath-hold was calculated as the inter-breath-hold (inter-BH) variability. All 16 patients tolerated the visual feedback-guided breath-hold maneuvers well. The intra- and inter-BH variability of all patients was 1.5 ± 0.6 mm and 1.2 ± 0.5 mm, respectively. A visual feedback-guided breath-hold technique using the machine vision system is feasible with good breath-hold reproducibility.

  13. Brain Damage in Commercial Breath-Hold Divers

    PubMed Central

    Kohshi, Kiyotaka; Tamaki, Hideki; Lemaître, Frédéric; Okudera, Toshio; Ishitake, Tatsuya; Denoble, Petar J.

    2014-01-01

    Background Acute decompression illness (DCI) involving the brain (Cerebral DCI) is one of the most serious forms of diving-related injuries which may leave residual brain damage. Cerebral DCI occurs in compressed air and in breath-hold divers, likewise. We conducted this study to investigate whether long-term breath-hold divers who may be exposed to repeated symptomatic and asymptomatic brain injuries, show brain damage on magnetic resonance imaging (MRI). Subjects and Methods Our study subjects were 12 commercial breath-hold divers (Ama) with long histories of diving work in a district of Japan. We obtained information on their diving practices and the presence or absence of medical problems, especially DCI events. All participants were examined with MRI to determine the prevalence of brain lesions. Results Out of 12 Ama divers (mean age: 54.9±5.1 years), four had histories of cerebral DCI events, and 11 divers demonstrated ischemic lesions of the brain on MRI studies. The lesions were situated in the cortical and/or subcortical area (9 cases), white matters (4 cases), the basal ganglia (4 cases), and the thalamus (1 case). Subdural fluid collections were seen in 2 cases. Conclusion These results suggest that commercial breath-hold divers are at a risk of clinical or subclinical brain injury which may affect the long-term neuropsychological health of divers. PMID:25115903

  14. Decompression sickness following breath-hold diving.

    PubMed

    Schipke, J D; Gams, E; Kallweit, Oliver

    2006-01-01

    Despite convincing evidence of a relationship between breath-hold diving and decompression sickness (DCS), the causal connection is only slowly being accepted. Only the more recent textbooks have acknowledged the risks of repetitive breath-hold diving. We compare four groups of breath-hold divers: (1) Japanese and Korean amas and other divers from the Pacific area, (2) instructors at naval training facilities, (3) spear fishers, and (4) free-dive athletes. While the number of amas is likely decreasing, and Scandinavian Navy training facilities recorded only a few accidents, the number of spear fishers suffering accidents is on the rise, in particular during championships or using scooters. Finally, national and international associations (e.g., International Association of Free Drives [IAFD] or Association Internationale pour Le Developpment De L'Apnee [AIDA]) promote free-diving championships including deep diving categories such as constant weight, variable weight, and no limit. A number of free-diving athletes, training for or participating in competitions, are increasingly accident prone as the world record is presently set at a depth of 171 m. This review presents data found after searching Medline and ISI Web of Science and using appropriate Internet search engines (e.g., Google). We report some 90 cases in which DCS occurred after repetitive breath-hold dives. Even today, the risk of suffering from DCS after repetitive breath-hold diving is often not acknowledged. We strongly suggest that breath-hold divers and their advisors and physicians be made aware of the possibility of DCS and of the appropriate therapeutic measures to be taken when DCS is suspected. Because the risk of suffering from DCS increases depending on depth, bottom time, rate of ascent, and duration of surface intervals, some approaches to assess the risks are presented. Regrettably, none of these approaches is widely accepted. We propose therefore the development of easily manageable

  15. 3D coronary MR angiography in multiple breath-holds using a respiratory feedback monitor.

    PubMed

    Wang, Y; Grimm, R C; Rossman, P J; Debbins, J P; Riederer, S J; Ehman, R L

    1995-07-01

    To reduce respiratory blur and ghosts in 3D coronary imaging, a data acquisition scheme using consistent multiple breath-holds was implemented. A navigator echo was acquired and processed in real time to dynamically measure diaphragm position. This information was provided as a visual prompt to the patient to maintain consistency in breath-hold levels such that the variation range of diastolic heart position was less than 2 mm. Preliminary results indicate that this multiple breath-hold acquisition scheme, compared with acquisition under respiration, can significantly reduce blur and ghost artifacts in 3D coronary imaging. PMID:7674888

  16. Kidney motion during free breathing and breath hold for MR-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Stam, Mette K.; van Vulpen, Marco; Barendrecht, Maurits M.; Zonnenberg, Bernard A.; Intven, Martijn; Crijns, Sjoerd P. M.; Lagendijk, Jan J. W.; Raaymakers, Bas W.

    2013-04-01

    Current treatments for renal cell carcinoma have a high complication rate due to the invasiveness of the treatment. With the MRI-linac it may be possible to treat renal tumours non-invasively with high-precision radiotherapy. This is expected to reduce complications. To deliver a static dose distribution, radiation gating will be used. In this study the reproducibility and efficiency of free breathing gating and a breath hold treatment of the kidney was investigated. For 15 patients with a renal lesion the kidney motion during 2 min of free breathing and 10 consecutive expiration breath holds was studied with 2D cine MRI. The variability in kidney expiration position and treatment efficiency for gating windows of 1 to 20 mm was measured for both breathing patterns. Additionally the time trend in free breathing and the variation in expiration breath hold kidney position with baseline shift correction was determined. In 80% of the patients the variation in expiration position during free breathing is smaller than 2 mm. No clinically relevant time trends were detected. The variation in expiration breath hold is for all patients larger than the free breathing expiration variation. Gating on free breathing is, for gating windows of 1 to 5 mm more efficient than breath hold without baseline correction. When applying a baseline correction to the breath hold it increases the treatment efficiency. The kidney position is more reproducible in expiration free breathing than non-guided expiration breath hold. For small gating windows it is also more time efficient. Since free breathing also seems more comfortable for the patients it is the preferred breathing pattern for MRI-Linac treatments of the kidney.

  17. The Physics of Breath-Hold Diving.

    ERIC Educational Resources Information Center

    Aguilella, Vicente; Aguilella-Arzo, Marcelo

    1996-01-01

    Analyzes physical features of breath-hold diving. Considers the diver's descent and the initial surface dive and presents examples that show the diver's buoyancy equilibrium varying with depth, the driving force supplied by finning, and the effect of friction between the water and the diver. (Author/JRH)

  18. Haemoptysis after breath-hold diving.

    PubMed

    Boussuges, A; Pinet, C; Thomas, P; Bergmann, E; Sainty, J M; Vervloet, D

    1999-03-01

    Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain this type of accident. Furthermore, these divers had taken aspirin, which may have aggravated the bleeding. PMID:10232449

  19. Anatomic and Pathologic Variability During Radiotherapy for a Hybrid Active Breath-Hold Gating Technique

    SciTech Connect

    Glide-Hurst, Carri K.; Gopan, Ellen; Hugo, Geoffrey D.

    2010-07-01

    Purpose: To evaluate intra- and interfraction variability of tumor and lung volume and position using a hybrid active breath-hold gating technique. Methods and Materials: A total of 159 repeat normal inspiration active breath-hold CTs were acquired weekly during radiotherapy for 9 lung cancer patients (12-21 scans per patient). A physician delineated the gross tumor volume (GTV), lungs, and spinal cord on the first breath-hold CT, and contours were propagated semiautomatically. Intra- and interfraction variability of tumor and lung position and volume were evaluated. Tumor centroid and border variability were quantified. Results: On average, intrafraction variability of lung and GTV centroid position was <2.0 mm. Interfraction population variability was 3.6-6.7 mm (systematic) and 3.1-3.9 mm (random) for the GTV centroid and 1.0-3.3 mm (systematic) and 1.5-2.6 mm (random) for the lungs. Tumor volume regressed 44.6% {+-} 23.2%. Gross tumor volume border variability was patient specific and demonstrated anisotropic shape change in some subjects. Interfraction GTV positional variability was associated with tumor volume regression and contralateral lung volume (p < 0.05). Inter-breath-hold reproducibility was unaffected by time point in the treatment course (p > 0.1). Increases in free-breathing tidal volume were associated with increases in breath-hold ipsilateral lung volume (p < 0.05). Conclusions: The breath-hold technique was reproducible within 2 mm during each fraction. Interfraction variability of GTV position and shape was substantial because of tumor volume and breath-hold lung volume change during therapy. These results support the feasibility of a hybrid breath-hold gating technique and suggest that online image guidance would be beneficial.

  20. Comparison of Multi-Echo Dixon Methods with Volume Interpolated Breath-Hold Gradient Echo Magnetic Resonance Imaging in Fat-Signal Fraction Quantification of Paravertebral Muscle

    PubMed Central

    Yoo, Yeon Hwa; Kim, Hak-Sun; Lee, Young Han; Yoon, Choon-Sik; Paek, Mun Young; Yoo, Hanna; Kannengiesser, Stephan; Chung, Tae-Sub; Song, Ho-Taek; Suh, Jin-Suck

    2015-01-01

    Objective To assess whether multi-echo Dixon magnetic resonance (MR) imaging with simultaneous T2* estimation and correction yields more accurate fat-signal fraction (FF) measurement of the lumbar paravertebral muscles, in comparison with non-T2*-corrected two-echo Dixon or T2*-corrected three-echo Dixon, using the FF measurements from single-voxel MR spectroscopy as the reference standard. Materials and Methods Sixty patients with low back pain underwent MR imaging with a 1.5T scanner. FF mapping images automatically obtained using T2*-corrected Dixon technique with two (non-T2*-corrected), three, and six echoes, were compared with images from single-voxel MR spectroscopy at the paravertebral muscles on levels L4 through L5. FFs were measured directly by two radiologists, who independently drew the region of interest on the mapping images from the three sequences. Results A total of 117 spectroscopic measurements were performed either bilaterally (57 of 60 subjects) or unilaterally (3 of 60 subjects). The mean spectroscopic FF was 14.3 ± 11.7% (range, 1.9-63.7%). Interobserver agreement was excellent between the two radiologists. Lin's concordance correlation between the spectroscopic findings and all the imaging-based FFs were statistically significant (p < 0.001). FFs obtained from the T2*-corrected six-echo Dixon sequences showed a significantly better concordance with the spectroscopic data, with its concordance correlation coefficient being 0.99 and 0.98 (p < 0.001), as compared with two- or three-echo methods. Conclusion T2*-corrected six-echo Dixon sequence would be a better option than two- or three-echo methods for noninvasive quantification of lumbar muscle fat quantification. PMID:26357503

  1. Cardiac function during breath-hold diving in humans: an echocardiographic study.

    PubMed

    Marabotti, C; Belardinelli, A; L'Abbate, A; Scalzini, A; Chiesa, F; Cialoni, D; Passera, M; Bedini, R

    2008-01-01

    Breath-hold diving induces, in marine mammals, a reduction of cardiac output due to a decrease of both heart rate and stroke volume. Cardiovascular changes in humans during breath-hold diving are only partially known due to the technical difficulty of studying fully immersed subjects. Recently, a submersible echocardiograph has been developed, allowing a feasible assessment of cardiac anatomy and function of subjects during diving. Aim of the study was to evaluate, by Doppler-echocardiography, the cardiovascular changes inducedby breath-hold diving in humans. Ten male subjects were studied by Doppler echocardiography in dry conditions and during breath-hold diving at 3 m depth. In addition 14 male subjects were studied, using the same protocol, before and during breath-hold diving at 10 m depth. At 3 m depth significant reductions in heart rate (-17%), stroke volume (-17%), cardiac output (-29%), left atrial dimensions, and deceleration time of early diastolic transmitral flow (DTE) were observed. At 10 m depth similar but more pronounced changes occurred. In particular, increase in early transmitral flow velocity became significant (+33%), while DTE decreased by 34%. At both depths dimensions of right cardiac chambers remained unchanged. Breath-hold diving at shallow depth induced, in humans, cardiovascular changes qualitatively similar to those observed in natural divers such as seals. The reduced dimensions of left atrium associated to a left ventricular diastolic pattern resembling that of restrictive/constrictive heart disease, suggest that the hemodynamic effects of diving could be explained, at least in part, by a constriction exerted on the heart by the reduced chest volume and the increased blood content of the lungs. Finally, the absence of dimensional changes in the right chambers suggests that most of the pulmonary blood shift occurred before cardiac imaging. PMID:18500072

  2. Acute effects of cannabis on breath-holding duration.

    PubMed

    Farris, Samantha G; Metrik, Jane

    2016-08-01

    Distress intolerance (an individual's perceived or actual inability to tolerate distressing psychological or physiological states) is associated with cannabis use. It is unknown whether a biobehavioral index of distress intolerance, breath-holding duration, is acutely influenced (increased or decreased) by cannabis. Such information may further inform understanding of the expression of psychological or physiological distress postcannabis use. This within-subjects study examined whether smoked marijuana with 2.7%-3.0% delta-9-tetrahydrocannabinol (THC), relative to placebo, acutely changed duration of breath holding. Participants (n = 88; 65.9% male) were nontreatment-seeking frequent cannabis users who smoked placebo or active THC cigarette on two separate study days and completed a breath-holding task postsmoking. Controlling for baseline breath-holding duration and participant sex, THC produced significantly shorter breath-holding durations relative to placebo. There was a significant interaction of drug administration × frequency of cannabis use, such that THC decreased breath-holding time among less frequent but not among more frequent users. Findings indicate that cannabis may exacerbate distress intolerance (via shorter breath-holding durations). As compared to less frequent cannabis users, frequent users display tolerance to cannabis' acute effects including increased ability to tolerate respiratory distress when holding breath. Objective measures of distress intolerance are sensitive to contextual factors such as acute drug intoxication, and may inform the link between cannabis use and the expression of psychological distress. (PsycINFO Database Record PMID:27454678

  3. Novel Findings in Breath-Holding Spells

    PubMed Central

    Azab, Seham F.A.; Siam, Ahmed G.; Saleh, Safaa H.; Elshafei, Mona M.; Elsaeed, Wafaa F.; Arafa, Mohamed A.; Bendary, Eman A.; Farag, Elsayed M.; Basset, Maha A.A.; Ismail, Sanaa M.; Elazouni, Osama M.A.

    2015-01-01

    Abstract The mechanism of breath-holding spells (BHS) is not fully understood and most probably multifactorial; so, this study was designed to clarify the pathophysiology of BHS through assessing some laboratory parameters and electrocardiographic (ECG) changes which might be contributing to the occurrence of the attacks. Another aim of the study was to evaluate the differences in the pathophysiology between pallid and cyanotic types of BHS. This was a prospective study performed in Zagazig University Hospitals. Seventy-six children diagnosed with BHS were included as follows: 32 children with cyanotic BHS, 14 children with pallid BHS, and 30 healthy children as a control group. All children were subjected to the following: full history taking, clinical examination, and laboratory work up in the form of CBC, serum iron, ferritin, and zinc levels. Twenty-four hours ambulatory ECG (Holter) recording was also performed. No significant statistical difference was found between cyanotic and pallid groups regarding family history of BHS, severity, and precipitating factors of the attacks. Frequent runs of respiratory sinus arrhythmia (RSA) during 24 hours ECG were significantly higher in children with BHS; the frequency of RSA was significantly correlated with the frequency (severity) of the attacks. Low serum ferritin was significantly associated with BHS groups but not correlated with the severity of the attacks. Autonomic dysregulation evidenced by frequent RSA is considered to be an important cause of BHS in children and is correlated with the frequency of the attacks. Low serum ferritin is additional factor in the pathophysiology. Both pallid and cyanotic BHS are suggested to be types of the same disease sharing the same pathophysiology. PMID:26181556

  4. Impact of breath holding on cardiovascular respiratory and cerebrovascular health.

    PubMed

    Dujic, Zeljko; Breskovic, Toni

    2012-06-01

    Human underwater breath-hold diving is a fascinating example of applied environmental physiology. In combination with swimming, it is one of the most popular forms of summer outdoor physical activities. It is performed by a variety of individuals ranging from elite breath-hold divers, underwater hockey and rugby players, synchronized and sprint swimmers, spear fishermen, sponge harvesters and up to recreational swimmers. Very few data currently exist concerning the influence of regular breath holding on possible health risks such as cerebrovascular, cardiovascular and respiratory diseases. A literature search of the PubMed electronic search engine using keywords 'breath-hold diving' and 'apnoea diving' was performed. This review focuses on recent advances in knowledge regarding possibly harmful physiological changes and/or potential health risks associated with breath-hold diving. Available evidence indicates that deep breath-hold dives can be very dangerous and can cause serious acute health problems such a collapse of the lungs, barotrauma at descent and ascent, pulmonary oedema and alveolar haemorrhage, cardiac arrest, blackouts, nitrogen narcosis, decompression sickness and death. Moreover, even shallow apnoea dives, which are far more frequent, can present a significant health risk. The state of affairs is disturbing as athletes, as well as recreational individuals, practice voluntary apnoea on a regular basis. Long-term health risks of frequent maximal breath holds are at present unknown, but should be addressed in future research. Clearly, further studies are needed to better understand the mechanisms related to the possible development or worsening of different clinical disorders in recreational or competitive breath holding and to determine the potential changes in training/competition regimens in order to prevent these adverse events. PMID:22574634

  5. Cardiovascular changes during maximal breath-holding in elite divers.

    PubMed

    Guaraldi, Pietro; Serra, Maria; Barletta, Giorgio; Pierangeli, Giulia; Terlizzi, Rossana; Calandra-Buonaura, Giovanna; Cialoni, Danilo; Cortelli, Pietro

    2009-12-01

    During maximal breath-holding six healthy elite breath-hold divers, after an initial "easy-going" phase in which cardiovascular changes resembled the so-called "diving response", exhibited a sudden and severe rise in blood pressure during the "struggle" phase of the maneuver. These changes may represent the first tangible expression of a defense reaction, which overrides the classic diving reflex, aiming to reduce the hypoxic damage and to break the apnea before the loss of consciousness. PMID:19655193

  6. TH-C-12A-11: Target Correlation of a 3D Surface Surrogate for Left Breast Irradiation Using the Respiratory-Gated Deep-Inspiration Breath-Hold Technique

    SciTech Connect

    Rong, Y; Walston, S

    2014-06-15

    Purpose: To evaluate the use of 3D optical surface imaging as a new surrogate for respiratory motion gated deep-inspiration breath-hold (DIBH) technique for left breast cancer patients. Methods: Patients with left-sided breast cancer after lumpectomy or mastectomy were selected as candidates for DIBH technique for their external beam radiation therapy. Treatment plans were created on both free breathing (FB) and DIBH CTs to determine whether DIBH was beneficial in reducing heart doses. The Real-time Position Management (RPM) system was used to acquire patient's breathing trace during DIBH CT acquisition and treatment delivery. The reference 3D surface models from FB and DIBH CTs were generated and transferred to the “AlignRT” system for patient positioning and real-time treatment monitoring. MV Cine images were acquired for each beam as quality assurance for intra-fractional position verification. The chest wall excursions measured on these images were used to define the actual target position during treatment, and to investigate the accuracy and reproducibility of RPM and AlignRT. Results: Reduction in heart dose can be achieved for left-sided breast patients using DIBH. Results showed that RPM has poor correlation with target position, as determined by the MV Cine imaging. This indicates that RPM may not be an adequate surrogate in defining the breath-hold level when used alone. Alternatively, the AlignRT surface imaging demonstrated a better correlation with the actual CW excursion during DIBH. Both the vertical and magnitude real-time deltas (RTDs) reported by AlignRT can be used as the gating parameter, with a recommend threshold of ±3 mm and 5 mm, respectively. Conclusion: 3D optical surface imaging serves as a superior target surrogate for the left breast treatment when compared to RPM. Working together with the realtime MV Cine imaging, they ensure accurate patient setup and dose delivery, while minimizing the imaging dose to patients.

  7. Multiview 3-D Echocardiography Fusion with Breath-Hold Position Tracking Using an Optical Tracking System.

    PubMed

    Punithakumar, Kumaradevan; Hareendranathan, Abhilash R; McNulty, Alexander; Biamonte, Marina; He, Allen; Noga, Michelle; Boulanger, Pierre; Becher, Harald

    2016-08-01

    Recent advances in echocardiography allow real-time 3-D dynamic image acquisition of the heart. However, one of the major limitations of 3-D echocardiography is the limited field of view, which results in an acquisition insufficient to cover the whole geometry of the heart. This study proposes the novel approach of fusing multiple 3-D echocardiography images using an optical tracking system that incorporates breath-hold position tracking to infer that the heart remains at the same position during different acquisitions. In six healthy male volunteers, 18 pairs of apical/parasternal 3-D ultrasound data sets were acquired during a single breath-hold as well as in subsequent breath-holds. The proposed method yielded a field of view improvement of 35.4 ± 12.5%. To improve the quality of the fused image, a wavelet-based fusion algorithm was developed that computes pixelwise likelihood values for overlapping voxels from multiple image views. The proposed wavelet-based fusion approach yielded significant improvement in contrast (66.46 ± 21.68%), contrast-to-noise ratio (49.92 ± 28.71%), signal-to-noise ratio (57.59 ± 47.85%) and feature count (13.06 ± 7.44%) in comparison to individual views. PMID:27166019

  8. The physiology and pathophysiology of human breath-hold diving.

    PubMed

    Lindholm, Peter; Lundgren, Claes E G

    2009-01-01

    This is a brief overview of physiological reactions, limitations, and pathophysiological mechanisms associated with human breath-hold diving. Breath-hold duration and ability to withstand compression at depth are the two main challenges that have been overcome to an amazing degree as evidenced by the current world records in breath-hold duration at 10:12 min and depth of 214 m. The quest for even further performance enhancements continues among competitive breath-hold divers, even if absolute physiological limits are being approached as indicated by findings of pulmonary edema and alveolar hemorrhage postdive. However, a remarkable, and so far poorly understood, variation in individual disposition for such problems exists. Mortality connected with breath-hold diving is primarily concentrated to less well-trained recreational divers and competitive spearfishermen who fall victim to hypoxia. Particularly vulnerable are probably also individuals with preexisting cardiac problems and possibly, essentially healthy divers who may have suffered severe alternobaric vertigo as a complication to inadequate pressure equilibration of the middle ears. The specific topics discussed include the diving response and its expression by the cardiovascular system, which exhibits hypertension, bradycardia, oxygen conservation, arrhythmias, and contraction of the spleen. The respiratory system is challenged by compression of the lungs with barotrauma of descent, intrapulmonary hemorrhage, edema, and the effects of glossopharyngeal insufflation and exsufflation. Various mechanisms associated with hypoxia and loss of consciousness are discussed, including hyperventilation, ascent blackout, fasting, and excessive postexercise O(2) consumption. The potential for high nitrogen pressure in the lungs to cause decompression sickness and N(2) narcosis is also illuminated. PMID:18974367

  9. Optical measures of changes in cerebral vascular tone during voluntary breath holding and a Sternberg memory task.

    PubMed

    Tan, Chin Hong; Low, Kathy A; Schneider-Garces, Nils; Zimmerman, Benjamin; Fletcher, Mark A; Maclin, Edward L; Chiarelli, Antonio M; Gratton, Gabriele; Fabiani, Monica

    2016-07-01

    The human cerebral vasculature responds to changes in blood pressure and demands for oxygenation via cerebral autoregulation. Changes in cerebrovascular tone (vasoconstriction and vasodilation) also mediate the changes in blood flow measured by the BOLD fMRI signal. This cerebrovascular reactivity is known to vary with age. In two experiments, we demonstrate that cerebral pulse parameters measured using optical imaging can quantify changes in cerebral vascular tone, both globally and locally. In experiment 1, 51 older adults (age range=55-87) performed a voluntary breath-holding task while cerebral pulse amplitude measures were taken. We found significant pulse amplitude variations across breath-holding periods, indicating vasodilation during, and vasoconstriction after breath holding. The breath-holding index (BHI), a measure of cerebrovascular reactivity (CVR) was derived and found to correlate with age. BHI was also correlated with performance in the Modified Mini-Mental Status Examination, even after controlling for age and education. In experiment 2, the same participants performed a Sternberg task, and changes in regional pulse amplitude between high (set-size 6) and low (set-size 2) task loads were compared. Only task-related areas in the fronto-parietal network (FPN) showed significant reduction in pulse amplitude, indicating vasodilation. Non-task-related areas such as the somatosensory and auditory cortices did not show such reductions. Taken together, these experiments suggest that optical pulse parameters can index changes in brain vascular tone both globally and locally, using both physiological and cognitive load manipulations. PMID:27235126

  10. Reduced breath holding index in patients with chronic migraine.

    PubMed

    Akgün, Hakan; Taşdemir, Serdar; Ulaş, Ümit Hıdır; Alay, Semih; Çetiz, Ahmet; Yücel, Mehmet; Öz, Oğuzhan; Odabaşı, Zeki; Demirkaya, Şeref

    2015-09-01

    Migraine is a neurovascular disorder characterized by autonomic nervous system dysfunction and severe headache attacks. Studies have shown that changes in the intracranial vessels during migraine have an important role in the pathophysiology. Many studies have been conducted on the increased risk of stroke in patients with migraine, but insufficient data are available on the mechanism underlying the increase. This study aimed to evaluate basal cerebral blood flow velocity and vasomotor reactivity in patients with chronic migraine. We evaluated 38 patients with chronic migraine. Three of them were excluded because they had auras and four of them were excluded because of their use of medication that can affect cerebral blood flow velocity and breath holding index (beta or calcium channel blockers). Our study population consisted of 31 patients with chronic migraine without aura and 29 age- and gender-matched healthy individuals who were not taking any medication. The mean blood flow velocity and breath holding index were measured on both sides from the middle cerebral artery and posterior cerebral artery, with temporal window insonation. The breath holding index for middle cerebral artery and posterior cerebral artery was significantly lower in the migraine group compared to that of the control group (p < 0.05).The vasomotor reactivity indicates the dilatation potential of a vessel, and it is closely related to autoregulation. According to our results, the vasodilator response of cerebral arterioles to hypercapnia was lower in patients with chronic migraine. These findings showed the existence of impairments in the harmonic cerebral hemodynamic mechanisms in patients with chronic migraine. This finding also supports the existing idea of an increased risk of stroke in patients with chronic migraine due to impaired vasomotor reactivity. PMID:25308111

  11. Energy cost and optimisation in breath-hold diving.

    PubMed

    Trassinelli, M

    2016-05-01

    We present a new model for calculating locomotion costs in breath-hold divers. Starting from basic mechanics principles, we calculate the work that the diver must provide through propulsion to counterbalance the action of drag, the buoyant force and weight during immersion. Compared to those in previous studies, the model presented here accurately analyses breath-hold divers which alternate active swimming with prolonged glides during the dive (as is the case in mammals). The energy cost of the dive is strongly dependent on these prolonged gliding phases. Here we investigate the length and impacts on energy cost of these glides with respect to the diver characteristics, and compare them with those observed in different breath-hold diving species. Taking into account the basal metabolic rate and chemical energy to propulsion transformation efficiency, we calculate optimal swim velocity and the corresponding total energy cost (including metabolic rate) and compare them with observations. Energy cost is minimised when the diver passes through neutral buoyancy conditions during the dive. This generally implies the presence of prolonged gliding phases in both ascent and descent, where the buoyancy (varying with depth) is best used against the drag, reducing energy cost. This is in agreement with past results (Miller et al., 2012; Sato et al., 2013) where, when the buoyant force is considered constant during the dive, the energy cost was minimised for neutral buoyancy. In particular, our model confirms the good physical adaption of dolphins for diving, compared to other breath-hold diving species which are mostly positively buoyant (penguins for example). The presence of prolonged glides implies a non-trivial dependency of optimal speed on maximal depth of the dive. This extends previous findings (Sato et al., 2010; Watanabe et al., 2011) which found no dependency of optimal speed on dive depth for particular conditions. The energy cost of the dive can be further

  12. Essential Hypertension: Cardiovascular Response to Breath Hold Combined with Exercise.

    PubMed

    Hoffmann, U; Urban, P; Koschate, J; Drescher, U; Pfister, R; Michels, G

    2015-07-01

    Essential hypertension (EH) is a widespread disease and might be prevalent in apnea divers and master athletes. Little is known about the influence of EH and the antihypertensive drugs (AHD) on cardiovascular reactions to combined breath hold (BH) and exercise. In this pilot study, healthy divers (HCON) were compared with treated hypertensive divers with regard to heart rate (HR) and mean blood-pressure (MAP) responses to BH, exercise and the combination of both. Ten subjects with EH and ten healthy divers were tested. 3 different 20 s stimuli were applied: BH combined with 30 W or 150 W and 150 W without BH. The time-charts during the stress intervals and during recovery were compared. Subjects treated with an angiotensin-converting enzyme (ACE) inhibitor showed higher changes for MAP values if breath hold was performed. HR responses were obviously changed if a β-blocker was part of the medication. One subject showed extreme MAP responses to all stimuli and conspicuous HR if BH was involved. The modulation of HR-/MAP-response in EH subjects depends on the mechanisms of antihypertensive agents. The combination of an ACE inhibitor and a β-blocker may give the best protection. It is recommended to include short apnea tests in the fitness-to-dive examination to individually predict potential endangerment. PMID:25875316

  13. Effect of gender on maximal breath-hold time.

    PubMed

    Cherouveim, Evgenia D; Botonis, Petros G; Koskolou, Maria D; Geladas, Nickos D

    2013-05-01

    This study examined the effect of gender on breath-hold time (BHT). Sixteen healthy subjects, eight males (M) and eight females (F), aged 18-30 years, without breath-hold (BH) experience, performed: (a) a pulmonary function test, (b) an incremental cycle ergometer test to exhaustion and (c) a BH protocol, which included eight repeated maximal efforts separated by 2-min intervals on two occasions: without (BHFOI) and with face immersion (BHFI) in cool water (14.8 ± 0.07 °C). Cardiovascular, ventilatory and hematological responses were studied before, during and after BH efforts. Maximal BHT was similar between genders (M: 103.90 ± 25.68 s; F: 104.97 ± 32.71 s, p > 0.05) and unaffected by face immersion (BHFOI: 105.13 ± 28.68 s; BHFI: 103.74 ± 31.19 s, p > 0.05). The aerobic capacity, lung volumes and hematological indexes were higher in males compared to females. BHT was predicted (r (2) = 0.98, p = 0.005) by aerobic capacity, total lung volume, hematocrit and hemoglobin concentration only in males. It was concluded that despite gender differences in physiological and anthropometrical traits, BH ability was not different between males and females, both not experienced in apneas. PMID:23187428

  14. Decompression sickness in breath-hold divers: a review.

    PubMed

    Lemaitre, Frederic; Fahlman, Andreas; Gardette, Bernard; Kohshi, Kiyotaka

    2009-12-01

    Although it has been generally assumed that the risk of decompression sickness is virtually zero during a single breath-hold dive in humans, repeated dives may result in a cumulative increase in the tissue and blood nitrogen tension. Many species of marine mammals perform extensive foraging bouts with deep and long dives interspersed by a short surface interval, and some human divers regularly perform repeated dives to 30-40 m or a single dive to more than 200 m, all of which may result in nitrogen concentrations that elicit symptoms of decompression sickness. Neurological problems have been reported in humans after single or repeated dives and recent necropsy reports in stranded marine mammals were suggestive of decompression sickness-like symptoms. Modelling attempts have suggested that marine mammals may live permanently with elevated nitrogen concentrations and may be at risk when altering their dive behaviour. In humans, non-pathogenic bubbles have been recorded and symptoms of decompression sickness have been reported after repeated dives to modest depths. The mechanisms implicated in these accidents indicate that repeated breath-hold dives with short surface intervals are factors that predispose to decompression sickness. During deep diving, the effect of pulmonary shunts and/or lung collapse may play a major role in reducing the incidence of decompression sickness in humans and marine mammals. PMID:19967580

  15. Assessing and ensuring patient safety during breath-holding for radiotherapy

    PubMed Central

    Green, S; Stevens, A M; Clutton-Brock, T H

    2014-01-01

    Objective: While there is recent interest in using repeated deep inspiratory breath-holds, or prolonged single breath-holds, to improve radiotherapy delivery, breath-holding has risks. There are no published guidelines for monitoring patient safety, and there is little clinical awareness of the pronounced blood pressure rise and the potential for gradual asphyxia that occur during breath-holding. We describe the blood pressure rise during deep inspiratory breath-holding with air and test whether it can be abolished simply by pre-oxygenation and hypocapnia. Methods: We measured blood pressure, oxygen saturation (SpO2) and heart rate in 12 healthy, untrained subjects performing breath-holds. Results: Even for deep inspiratory breath-holds with air, the blood pressure rose progressively (e.g. mean systolic pressure rose from 133 ± 5 to 175 ± 8 mmHg at breakpoint, p < 0.005, and in two subjects, it reached 200 mmHg). Pre-oxygenation and hypocapnia prolonged breath-hold duration and prevented the development of asphyxia but failed to abolish the pressure rise. The pressure rise was not a function of breath-hold duration and was not signalled by any fall in heart rate (remaining at resting levels of 72 ± 2 beats per minute). Conclusion: Colleagues should be aware of the progressive blood pressure rise during deep inspiratory breath-holding that so far is not easily prevented. In breast cancer patients scheduled for breath-holds, we recommend routine screening for heart, cardiovascular, renal and cerebrovascular disease, routine monitoring of patient blood pressure and SpO2 during breath-holding and requesting patients to stop if systolic pressure rises consistently >180 mmHg and or SpO2 falls <94%. Advances in knowledge: There is recent interest in using deep inspiratory breath-holds, or prolonged single breath-holding techniques, to improve radiotherapy delivery. But there appears to be no clinical awareness of the risks to patients from breath-holding

  16. The Ins and Outs of Breath Holding: Simple Demonstrations of Complex Respiratory Physiology

    ERIC Educational Resources Information Center

    Skow, Rachel J.; Day, Trevor A.; Fuller, Jonathan E.; Bruce, Christina D.; Steinback, Craig D.

    2015-01-01

    The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology…

  17. Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy

    PubMed Central

    Bartlett, Frederick R.; Colgan, Ruth M.; Donovan, Ellen M.; Carr, Karen; Landeg, Steven; Clements, Nicola; McNair, Helen A.; Locke, Imogen; Evans, Philip M.; Haviland, Joanne S.; Yarnold, John R.; Kirby, Anna M.

    2014-01-01

    Breath-holding techniques reduce the amount of radiation received by cardiac structures during tangential-field left breast radiotherapy. With these techniques, patients hold their breath while radiotherapy is delivered, pushing the heart down and away from the radiotherapy field. Despite clear dosimetric benefits, these techniques are not yet in widespread use. One reason for this is that commercially available solutions require specialist equipment, necessitating not only significant capital investment, but often also incurring ongoing costs such as a need for daily disposable mouthpieces. The voluntary breath-hold technique described here does not require any additional specialist equipment. All breath-holding techniques require a surrogate to monitor breath-hold consistency and whether breath-hold is maintained. Voluntary breath-hold uses the distance moved by the anterior and lateral reference marks (tattoos) away from the treatment room lasers in breath-hold to monitor consistency at CT-planning and treatment setup. Light fields are then used to monitor breath-hold consistency prior to and during radiotherapy delivery. PMID:25046661

  18. The ins and outs of breath holding: simple demonstrations of complex respiratory physiology.

    PubMed

    Skow, Rachel J; Day, Trevor A; Fuller, Jonathan E; Bruce, Christina D; Steinback, Craig D

    2015-09-01

    The physiology of breath holding is complex, and voluntary breath-hold duration is affected by many factors, including practice, psychology, respiratory chemoreflexes, and lung stretch. In this activity, we outline a number of simple laboratory activities or classroom demonstrations that illustrate the complexity of the integrative physiology behind breath-hold duration. These activities require minimal equipment and are easily adapted to small-group demonstrations or a larger-group inquiry format where students can design a protocol and collect and analyze data from their classmates. Specifically, breath-hold duration is measured during a number of maneuvers, including after end expiration, end inspiration, voluntary prior hyperventilation, and inspired hyperoxia. Further activities illustrate the potential contribution of chemoreflexes through rebreathing and repeated rebreathing after a maximum breath hold. The outcome measures resulting from each intervention are easily visualized and plotted and can comprise a comprehensive data set to illustrate and discuss complex and integrated cardiorespiratory physiology. PMID:26330043

  19. Improved 3-Tesla cardiac cine imaging using wideband.

    PubMed

    Lee, Hsu-Lei; Shankaranarayanan, Ajit; Pohost, Gerald M; Nayak, Krishna S

    2010-06-01

    Cine balanced steady-state free precession (SSFP) is the most widely used sequence for assessing cardiac ventricular function at 1.5 T because it provides high signal-to-noise ratio efficiency and strong contrast between myocardium and blood. At 3 T, the use of SSFP is limited by susceptibility-induced off-resonance, resulting in either banding artifacts or the need to use a short-sequence pulse repetition time that limits the readout duration and hence the achievable spatial resolution. In this work, we apply wideband SSFP, a variant of SSFP that uses two alternating pulse repetition times to establish a steady state with wider band spacing in its frequency response and overcome the key limitations of SSFP. Prospectively gated cine two-dimensional imaging with wideband SSFP is evaluated in healthy volunteers and compared to conventional balanced SSFP, using quantitative metrics and qualitative interpretation by experienced clinicians. We demonstrate that by trading off temporal resolution and signal-to-noise ratio efficiency, wideband SSFP mitigates banding artifacts and enables imaging with approximately 30% higher spatial resolution compared to conventional SSFP with the same effective band spacing. PMID:20512877

  20. Scaling of swim speed in breath-hold divers.

    PubMed

    Watanabe, Yuuki Y; Sato, Katsufumi; Watanuki, Yutaka; Takahashi, Akinori; Mitani, Yoko; Amano, Masao; Aoki, Kagari; Narazaki, Tomoko; Iwata, Takashi; Minamikawa, Shingo; Miyazaki, Nobuyuki

    2011-01-01

    1. Breath-hold divers are widely assumed to descend and ascend at the speed that minimizes energy expenditure per distance travelled (the cost of transport (COT)) to maximize foraging duration at depth. However, measuring COT with captive animals is difficult, and empirical support for this hypothesis is sparse. 2. We examined the scaling relationship of swim speed in free-ranging diving birds, mammals and turtles (37 species; mass range, 0·5-90,000 kg) with phylogenetically informed statistical methods and derived the theoretical prediction for the allometric exponent under the COT hypothesis by constructing a biomechanical model. 3. Swim speed significantly increased with mass, despite considerable variations around the scaling line. The allometric exponent (0·09) was statistically consistent with the theoretical prediction (0·05) of the COT hypothesis. 4. Our finding suggests a previously unrecognized advantage of size in divers: larger animals swim faster and thus could travel longer distance, search larger volume of water for prey and exploit a greater range of depths during a given dive duration. 5. Furthermore, as predicted from the model, endotherms (birds and mammals) swam faster than ectotherms (turtles) for their size, suggesting that metabolic power production limits swim speed. Among endotherms, birds swam faster than mammals, which cannot be explained by the model. Reynolds numbers of small birds (<2 kg) were close to the lower limit of turbulent flow (∼ 3 × 10(5) ), and they swam fast possibly to avoid the increased drag associated with flow transition. PMID:20946384

  1. Cine viability magnetic resonance imaging of the heart without increased scan time.

    PubMed

    Hassanein, Azza S; Khalifa, Ayman M; Ibrahim, El-Sayed H

    2016-02-01

    Cardiac magnetic resonance imaging (MRI) provides information about myocardial morphology, function, and viability from cine, tagged, and late gadolinium enhancement (LGE) images, respectively. While the cine and tagged images are acquired in a time-resolved fashion, the LGE images are acquired at a single timeframe. The purpose of this work is to develop a method for generating cine LGE images without additional scan time. The motion field is extracted from the tagged images, and is then used to guide the deformation of the infarcted region from the acquired LGE image at the acquired timeframe to any other timeframe. Major techniques for motion estimation, including harmonic phase (HARP) and optical flow analysis, are tested in this work for motion estimation. The proposed method is tested on numerical phantom and images from four human subjects. The generated cine LGE images showed both viability and wall motion information in the same set of images without additional scan time or image misregistration problems. The band-pass optical flow analysis resulted in the most accurate motion estimation compared to other methods, especially HARP, which fails to track points at the myocardial boundary. Infarct transmurality from the generated images showed good agreement with myocardial strain, and wall thickening showed good agreement with that measured from conventional cine images. In conclusion, the developed technique allows for generating cine LGE images that enable simultaneous display of wall motion and viability information. The generated images could be useful for estimating myocardial contractility reserve and for treatment prognosis. PMID:26528793

  2. Dynamic diaphragmatic MRI during apnea struggle phase in breath-hold divers.

    PubMed

    Batinic, Tonci; Mihanovic, Frane; Breskovic, Toni; Zubin-Maslov, Petra; Lojpur, Mihajlo; Mijacika, Tanja; Dujic, Zeljko

    2016-02-01

    The purpose of the study was to provide insight in diaphragmatic involuntary breathing movements (IBM) during struggle phase of apnea at total lung capacity (TLC) and functional residual capacity (FRC) using magnetic resonance imaging along with measurements of hemodynamics and arterial oxygenation. The study was performed in eight elite breath-hold divers. There was a similar increase in diaphragmatic cranio-caudal excursions towards the end of TLC and FRC apnea. The greatest diaphragmatic excursion in both apneas and during tidal breathing was in the middle and posterior part of the diaphragm. Diaphragm thickness in elite BHD was within the reference range of normal values suggesting no diaphragmatic hypertrophy in this population. We found that the range of diaphragmatic excursions increases toward the end of apneas. Additionally, our data suggest that the diaphragm participates in IBM occurrence and that various segments of the diaphragm behave nonhomogenously both in tidal breathing and IBMs. PMID:26644078

  3. SU-E-J-236: Audiovisual Biofeedback Improves Breath-Hold Lung Tumor Position Reproducibility Measured with 4D MRI

    SciTech Connect

    Lee, D; Pollock, S; Keall, P; Greer, P; Lapuz, C; Ludbrook, J; Kim, T

    2015-06-15

    Purpose: Audiovisual biofeedback breath-hold (AVBH) was employed to reproduce tumor position on inhale and exhale breath-holds for 4D tumor information. We hypothesize that lung tumor position will be more consistent using AVBH compared with conventional breath-hold (CBH). Methods: Lung tumor positions were determined for seven lung cancer patients (age: 25 – 74) during to two separate 3T MRI sessions. A breathhold training session was performed prior to the MRI sessions to allow patients to become comfortable with AVBH and their exhale and inhale target positions. CBH and AVBH 4D image datasets were obtained in the first MRI session (pre-treatment) and the second MRI session (midtreatment) within six weeks of the first session. Audio-instruction (MRI: Siemens Skyra) in CBH and verbal-instruction (radiographer) in AVBH were used. A radiation oncologist contoured the lung tumor using Eclipse (Varian Medical Systems); tumor position was quantified as the centroid of the contoured tumor after rigid registration based on vertebral anatomy across two MRI sessions. CBH and AVBH were compared in terms of the reproducibility assessed via (1) the difference between the two exhale positions for the two sessions and the two inhale positions for the sessions. (2) The difference in amplitude (exhale to inhale) between the two sessions. Results: Compared to CBH, AVBH improved the reproducibility of two exhale (or inhale) lung tumor positions relative to each other by 33%, from 6.4±5.3 mm to 4.3±3.0 mm (p=0.005). Compared to CBH, AVBH improved the reproducibility of exhale and inhale amplitude by 66%, from 5.6±5.9 mm to 1.9±1.4 mm (p=0.005). Conclusions: This study demonstrated that audiovisual biofeedback can be utilized for improving the reproducibility of breath-hold lung tumor position. These results are advantageous towards achieving more accurate emerging radiation treatment planning methods, in addition to imaging and treatment modalities utilizing breath-hold

  4. Respiratory hypoalgesia? Breath-holding, but not respiratory phase modulates nociceptive flexion reflex and pain intensity.

    PubMed

    Jafari, Hassan; Van de Broek, Karlien; Plaghki, Léon; Vlaeyen, Johan W S; Van den Bergh, Omer; Van Diest, Ilse

    2016-03-01

    Several observations suggest that respiratory phase (inhalation vs. exhalation) and post-inspiratory breath-holds could modulate pain and the nociceptive reflex. This experiment aimed to investigate the role of both mechanisms. Thirty-two healthy participants received supra-threshold electrocutaneous stimulations to elicit both the Nociceptive Flexion Reflex (NFR) and pain, either during spontaneous inhalations or exhalations, or during three types of instructed breath-holds: following exhalation, at mid-inhalation and at full-capacity inhalation. Whether the electrocutaneous stimulus was applied during inhalation or exhalation did not affect the NFR or pain. Self-reported pain was reduced and the NFR was increased during breath-holding compared to spontaneous breathing. Whereas the type of breath-hold did not impact on self-reported pain, breath-holds at full-capacity inhalation and following exhalation were associated with a lower NFR amplitude compared to breath-holds at mid-inhalation. The present findings confirm that breath-holding can modulate pain (sensitivity) and suggest that both attentional distraction and changes in vagal activity may underlie the observed effects. PMID:26808697

  5. Breath-Hold Target Localization With Simultaneous Kilovoltage/Megavoltage Cone-Beam Computed Tomography and Fast Reconstruction

    SciTech Connect

    Blessing, Manuel; Stsepankou, Dzmitry; Wertz, Hansjoerg; Arns, Anna; Lohr, Frank; Hesser, Juergen; Wenz, Frederik

    2010-11-15

    Purpose: Hypofractionated high-dose radiotherapy for small lung tumors has typically been based on stereotaxy. Cone-beam computed tomography and breath-hold techniques have provided a noninvasive basis for precise cranial and extracranial patient positioning. The cone-beam computed tomography acquisition time of 60 s, however, is beyond the breath-hold capacity of patients, resulting in respiratory motion artifacts. By combining megavoltage (MV) and kilovoltage (kV) photon sources (mounted perpendicularly on the linear accelerator) and accelerating the gantry rotation to the allowed limit, the data acquisition time could be reduced to 15 s. Methods and Materials: An Elekta Synergy 6-MV linear accelerator, with iViewGT as the MV- and XVI as the kV-imaging device, was used with a Catphan phantom and an anthropomorphic thorax phantom. Both image sources performed continuous image acquisition, passing an angle interval of 90{sup o} within 15 s. For reconstruction, filtered back projection on a graphics processor unit was used. It reconstructed 100 projections acquired to a 512 x 512 x 512 volume within 6 s. Results: The resolution in the Catphan phantom (CTP528 high-resolution module) was 3 lines/cm. The spatial accuracy was within 2-3 mm. The diameters of different tumor shapes in the thorax phantom were determined within an accuracy of 1.6 mm. The signal-to-noise ratio was 68% less than that with a 180{sup o}-kV scan. The dose generated to acquire the MV frames accumulated to 82.5 mGy, and the kV contribution was <6 mGy. Conclusion: The present results have shown that fast breath-hold, on-line volume imaging with a linear accelerator using simultaneous kV-MV cone-beam computed tomography is promising and can potentially be used for image-guided radiotherapy for lung cancer patients in the near future.

  6. Diverse Presentation of Breath Holding Spells: Two Case Reports with Literature Review

    PubMed Central

    Rathore, Geetanjali; Larsen, Paul; Fernandez, Cristina; Parakh, Manish

    2013-01-01

    Breath holding spells are a common and dramatic form of syncope and anoxic seizure in infancy. They are usually triggered by an emotional stimuli or minor trauma. Based on the color change, they are classified into 3 types, cyanotic, pallid, and mixed. Pallid breath holding spells result from exaggerated, vagally-mediated cardiac inhibition, whereas the more common, cyanotic breathholding spells are of more complex pathogenesis which is not completely understood. A detailed and accurate history is the mainstay of diagnosis. An EKG should be strongly considered to rule out long QT syndrome. Spontaneous resolution of breath-holding spells is usually seen, without any adverse developmental and intellectual sequelae. Rare cases of status epilepticus, prolonged asystole, and sudden death have been reported. Reassurance and education is the mainstay of therapy. Occasionally, pharmacologic intervention with iron, piracetam; atropine may be of benefit. Here we present 2 cases, one of each, pallid and cyanotic breath holding spells. PMID:24191206

  7. Case report of successful treatment of pallid breath-holding spells with glycopyrrolate.

    PubMed

    Williams, Jason; Cain, Nicole

    2015-05-01

    Breath-holding spells are a common childhood disorder that typically present before 12 months of age. Whereas most cases are benign, some patients have very severe cases associated with bradycardia that can progress from asystole to syncope and seizures. Treatment studies have implicated the use of several therapies, such as oral iron, fluoxetine, and pacemaker implantation. This is a retrospective study of patients treated with glycopyrrolate for pallid breath-holding spells. Clinical data from 4 patients referred to pediatric cardiology who saw therapeutic benefit from treatment using glycopyrrolate were reviewed to evaluate for clinical response to the drug. Two twin patients, whose symptoms began at 5 months of age, experienced a decrease in breath-holding frequency after 1 month. A patient diagnosed at 7 months of age experienced a decrease in frequency of spells. A patient diagnosed at 10 months of age reported cessation of syncope shortly after initiation of glycopyrrolate and complete resolution of breath-holding spells during prolonged treatment. This case study of 4 patients with pallid breath-holding offers evidence that glycopyrrolate may be beneficial in treating breath-holding spells and has a safer side-effect profile than pacemaker implantation. PMID:25869368

  8. Respiration-correlated treatment delivery using feedback-guided breath hold: A technical study

    SciTech Connect

    Nelson, Christopher; Starkschall, George; Balter, Peter; Fitzpatrick, Mathew J.; Antolak, John A.; Tolani, Naresh; Prado, Karl

    2005-01-01

    Respiratory motion causes movement of internal structures in the thorax and abdomen, making accurate delivery of radiation therapy to tumors in those areas a challenge. To reduce the uncertainties caused by this motion, we have developed feedback-guided breath hold (FGBH), a novel delivery technique in which radiation is delivered only during a voluntary breath hold that is sustained for as long as the patient feels comfortable. Here we present the technical aspects of FGBH, which involve (1) fabricating the hardware so the respiratory trace can be displayed to the patient, (2) assembling a delay box to be used as a breath-hold detector, and (3) performing quality control tests to ensure that FGBH can be delivered accurately and safely. A commercial respiratory tracking system that uses an external fiducial to monitor abdominal wall motion generates and displays the breathing trace and specific positions in the breathing cycle where a breath hold needs to occur. Hardware was developed to present this display to the patient in the treatment position. Patients view the presentation either on a liquid crystal display or through a pair of virtual reality goggles. Using the respiratory trace as a visual aid, the patient performs a breath hold so that the position representing the location of a fiducial is held within a specified gating window. A delay box was fabricated to differentiate between gating signals received during free breathing and those received during breath hold, allowing radiation delivery only when the fiducial was within the breath-hold gating window. A quality control analysis of the gating delay box and the integrated system was performed to ensure that all of the hardware and components were ready for clinical use.

  9. SU-E-J-234: Application of a Breathing Motion Model to ViewRay Cine MR Images

    SciTech Connect

    O’Connell, D. P.; Thomas, D. H.; Dou, T. H.; Lamb, J. M.; Yang, L.; Low, D. A.

    2015-06-15

    Purpose: A respiratory motion model previously used to generate breathing-gated CT images was used with cine MR images. Accuracy and predictive ability of the in-plane models were evaluated. Methods: Sagittalplane cine MR images of a patient undergoing treatment on a ViewRay MRI/radiotherapy system were acquired before and during treatment. Images were acquired at 4 frames/second with 3.5 × 3.5 mm resolution and a slice thickness of 5 mm. The first cine frame was deformably registered to following frames. Superior/inferior component of the tumor centroid position was used as a breathing surrogate. Deformation vectors and surrogate measurements were used to determine motion model parameters. Model error was evaluated and subsequent treatment cines were predicted from breathing surrogate data. A simulated CT cine was created by generating breathing-gated volumetric images at 0.25 second intervals along the measured breathing trace, selecting a sagittal slice and downsampling to the resolution of the MR cines. A motion model was built using the first half of the simulated cine data. Model accuracy and error in predicting the remaining frames of the cine were evaluated. Results: Mean difference between model predicted and deformably registered lung tissue positions for the 28 second preview MR cine acquired before treatment was 0.81 +/− 0.30 mm. The model was used to predict two minutes of the subsequent treatment cine with a mean accuracy of 1.59 +/− 0.63 mm. Conclusion: Inplane motion models were built using MR cine images and evaluated for accuracy and ability to predict future respiratory motion from breathing surrogate measurements. Examination of long term predictive ability is ongoing. The technique was applied to simulated CT cines for further validation, and the authors are currently investigating use of in-plane models to update pre-existing volumetric motion models used for generation of breathing-gated CT planning images.

  10. Hemoptysis Due to Breath-Hold Diving Following Chemotherapy and Lung Irradiation

    PubMed Central

    Gutsche, Markus; Kuschner, Ware G.

    2012-01-01

    Breath-hold diving, also known as free-diving, describes the practice of intentional immersion under water without an external supply of oxygen. Pulmonary hemorrhage with hemoptysis has been reported as a complication of immersion and breath-hold diving in young healthy athletes. We report the case of a 60-year-old man with a history of radiation and chemotherapy for breast carcinoma, who developed the abrupt onset of hemoptysis in the setting of swimming and breath-hold diving. A computed tomography (CT) scan of the chest demonstrated an area of ground glass opacification, suggestive of pulmonary hemorrhage, superimposed on a background of reticular opacities within the prior radiation field. A follow-up CT scan of the chest, obtained 2 months after presentation, demonstrated resolution of the ground glass opacification, but persistence of fibrotic features attributable to prior radiation therapy. We postulate that prior irradiation of the chest resulted in lung injury and fibrosis which, in turn, rendered the affected region of the lung susceptible to “stress failure,” due to an increase in the transcapillary pressure gradient arising from immersion and breath-hold diving. Patients with a history of lung injury resulting from chest irradiation should be cautioned about pulmonary hemorrhage and hemoptysis as a potential complication of swimming and breath-hold diving. PMID:22537760

  11. Lack of Correlation Between External Fiducial Positions and Internal Tumor Positions During Breath-Hold CT

    SciTech Connect

    Hunjan, Sandeep; Starkschall, George; Prado, Karl; Dong Lei; Balter, Peter

    2010-04-15

    Purpose: For thoracic tumors, if four-dimensional computed tomography (4DCT) is unavailable, the internal margin can be estimated by use of breath-hold (BH) CT scans acquired at end inspiration (EI) and end expiration (EE). By use of external surrogates for tumor position, BH accuracy is estimated by minimizing the difference between respiratory extrema BH and mean equivalent-phase free breathing (FB) positions. We tested the assumption that an external surrogate for BH accuracy correlates with internal tumor positional accuracy during BH CT. Methods and Materials: In 16 lung cancer patients, 4DCT images, as well as BH CT images at EI and EE, were acquired. Absolute differences between BH and mean equivalent-phase (FB) positions were calculated for both external fiducials and gross tumor volume (GTV) centroids as metrics of external and internal BH accuracy, respectively, and the results were correlated. Results: At EI, the absolute difference between mean FB and BH fiducial displacement correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R{sup 2} = 0.11). Similarly, at EE, the absolute difference between mean FB and BH fiducial displacements correlated poorly with the absolute difference between FB and BH GTV centroid positions on CT images (R{sup 2} = 0.18). Conclusions: External surrogates for tumor position are not an accurate metric of BH accuracy for lung cancer patients. This implies that care should be taken when using such an approach because an incorrect internal margin could be generated.

  12. SU-C-19A-01: A Simple Deep Inspiration Breath Hold System

    SciTech Connect

    Rasmussen, B; Kaznowski, L; Blackburn, J; Chu, K; Duelge, J; Baldwin, B; Valenti, M; Hunsader, A

    2014-06-15

    Purpose: Deep Inspiration Breath Hold (DIBH) Radiation therapy for left sided breast can reduce dose to the lungs and heart. The purpose of this work is to illustrate how to implement a simple method of DIBH for simulation and treatment using equipment readily available in most radiation oncology clinics. Methods: For simulation and treatment, a foam block is placed on the patient's abdomen or chest and a horizontal laser mounted on a movable slide is aimed at the center of the foam block. After a coaching session the block is marked at the average free breathing position and average DIBH position. The position of block relative to laser can be seen by the patient via prism glasses as well as the radiation therapists via a video camera system. Simulation CT scans and treatment delivery are performed under DIBH conditions. Imaging and treatment are performed by manually turning the beam on once the patient has achieved DIBH after being given verbal instructions. Results: Manually triggered imaging was used daily to verify DIBH reproducibility for all patients treated using this system. Sets of before and during port images were used to ensure patient position was appropriate for treatment. Results of the laser on block method were compared to a sister facility using surface mapping techniques for DIBH and the two methods were found to have clinically equivalent reproducibility. Conclusion: The laser and block system was found to be simple to implement and robust during patient treatment. This system can be created from readily available materials at low cost and provides adequate feedback to patient and therapists. During treatment images document the reproducibility of setup and give confidence to clinicians that this method is reproducible from day to day.

  13. Risk of decompression sickness in extreme human breath-hold diving.

    PubMed

    Fitz-Clarke, J R

    2009-01-01

    The risk of decompression sickness (DCS) in human breath-hold diving is expected to increase as dives progress deeper until a depth is reached where total lung collapse stops additional nitrogen gas uptake. We assembled a database of all documented human breath-hold dives to 100 metres or greater, including both practice and record dives. Between 1976 and 2006 there were 192 such dives confirmed by 24 divers (18 male, 6 female). The deepest dive was to 209 metres. There were two drowning fatalities, and two cases ofDCS. Depth-time risk estimates for DCS were derived for single breath-hold dives by modifying probabilistic decompression models calibrated with data from short deep no-stop air dives and submarine escape trials using maximum-likelihood estimation. Arterial nitrogen levels during apnea were adjusted for lung compression and decreased cardiac output. Predicted DCS risk is negligible up to about 100 metres, beyond which risk increases nonlinearly and reaches a plateau around 5 to 7 percent when total lung collapse occurs beyond 230 metres. Results are consistent with data available from deep breath-hold dives. PMID:19462748

  14. Spleen volume and blood flow response to repeated breath-hold apneas.

    PubMed

    Baković, Darija; Valic, Zoran; Eterović, Davor; Vukovic, Ivica; Obad, Ante; Marinović-Terzić, Ivana; Dujić, Zeljko

    2003-10-01

    The purpose of this study was 1) to answer whether the reduction in spleen size in breath-hold apnea is an active contraction or a passive collapse secondary to reduced splenic arterial blood flow and 2) to monitor the spleen response to repeated breath-hold apneas. Ten trained apnea divers and 10 intact and 7 splenectomized untrained persons repeated five maximal apneas (A1-A5) with face immersion in cold water, with 2 min interposed between successive attempts. Ultrasonic monitoring of the spleen and noninvasive cardiopulmonary measurements were performed before, between apneas, and at times 0, 10, 20, 40, and 60 min after the last apnea. Blood flows in splenic artery and splenic vein were not significantly affected by breath-hold apnea. The duration of apneas peaked after A3 (143, 127, and 74 s in apnea divers, intact, and splenectomized persons, respectively). A rapid decrease in spleen volume ( approximately 20% in both apnea divers and intact persons) was mainly completed throughout the first apnea. The spleen did not recover in size between apneas and only partly recovered 60 min after A5. The well-known physiological responses to apnea diving, i.e., bradycardia and increased blood pressure, were observed in A1 and remained unchanged throughout the following apneas. These results show rapid, probably active contraction of the spleen in response to breath-hold apnea in humans. Rapid spleen contraction and its slow recovery may contribute to prolongation of successive, briefly repeated apnea attempts. PMID:12819225

  15. A feasibility study of treatment verification using EPID cine images for hypofractionated lung radiotherapy

    NASA Astrophysics Data System (ADS)

    Tang, Xiaoli; Lin, Tong; Jiang, Steve

    2009-09-01

    We propose a novel approach for potential online treatment verification using cine EPID (electronic portal imaging device) images for hypofractionated lung radiotherapy based on a machine learning algorithm. Hypofractionated radiotherapy requires high precision. It is essential to effectively monitor the target to ensure that the tumor is within the beam aperture. We modeled the treatment verification problem as a two-class classification problem and applied an artificial neural network (ANN) to classify the cine EPID images acquired during the treatment into corresponding classes—with the tumor inside or outside of the beam aperture. Training samples were generated for the ANN using digitally reconstructed radiographs (DRRs) with artificially added shifts in the tumor location—to simulate cine EPID images with different tumor locations. Principal component analysis (PCA) was used to reduce the dimensionality of the training samples and cine EPID images acquired during the treatment. The proposed treatment verification algorithm was tested on five hypofractionated lung patients in a retrospective fashion. On average, our proposed algorithm achieved a 98.0% classification accuracy, a 97.6% recall rate and a 99.7% precision rate. This work was first presented at the Seventh International Conference on Machine Learning and Applications, San Diego, CA, USA, 11-13 December 2008.

  16. Nonrigid registration method to assess reproducibility of breath-holding with ABC in lung cancer

    SciTech Connect

    Sarrut, David . E-mail: dsarrut@univ-lyon2.fr; Boldea, Vlad; Ayadi, Myriam; Badel, Jean-Noel; Ginestet, Chantal; Clippe, Sebastien; Carrie, Christian

    2005-02-01

    Purpose: To study the interfraction reproducibility of breath-holding using active breath control (ABC), and to develop computerized tools to evaluate three-dimensional (3D) intrathoracic motion in each patient. Methods and materials: Since June 2002, 11 patients with non-small-cell lung cancer enrolled in a Phase II trial have undergone four CT scans: one during free-breathing (reference) and three using ABC. Patients left the room between breath-hold scans. The patient's breath was held at the same predefined phase of the breathing cycle (about 70% of the vital capacity) using the ABC device, then patients received 3D-conformal radiotherapy. Automated computerized tools for breath-hold CT scans were developed to analyze lung and tumor interfraction residual motions with 3D nonrigid registration. Results: All patients but one were safely treated with ABC for 7 weeks. For 6 patients, the lung volume differences were <5%. The mean 3D displacement inside the lungs was between 2.3 mm (SD 1.4) and 4 mm (SD 3.3), and the gross tumor volume residual motion was 0.9 mm (SD 0.4) to 5.9 mm (SD 0.7). The residual motion was slightly greater in the inferior part of the lung than the superior. For 2 patients, we detected volume changes >300 cm{sup 3} and displacements >10 mm, probably owing to atelectasia and emphysema. One patient was excluded, and two others had incomplete data sets. Conclusion: Breath-holding with ABC was effective in 6 patients, and discrepancies were clinically accountable in 2. The proposed 3D nonrigid registration method allows for personalized evaluation of breath-holding reproducibility with ABC. It will be used to adapt the patient-specific internal margins.

  17. Treatment of Chronic Breath-Holding in an Adult with Severe Mental Retardation: A Clinical Case Study

    ERIC Educational Resources Information Center

    Reed, Derek D.; Martens, Brian K.

    2008-01-01

    We describe a clinical case study surrounding the behavioral assessment and operant treatment of, an adult with severe mental retardation who engaged in chronic breath-holding. In this clinical case, previous neurological and medical testing had ruled out biological bases for the individual's breath-holding. A functional behavioral assessment…

  18. Analysis of 3-D Tongue Motion from Tagged and Cine Magnetic Resonance Images

    ERIC Educational Resources Information Center

    Xing, Fangxu; Woo, Jonghye; Lee, Junghoon; Murano, Emi Z.; Stone, Maureen; Prince, Jerry L.

    2016-01-01

    Purpose: Measuring tongue deformation and internal muscle motion during speech has been a challenging task because the tongue deforms in 3 dimensions, contains interdigitated muscles, and is largely hidden within the vocal tract. In this article, a new method is proposed to analyze tagged and cine magnetic resonance images of the tongue during…

  19. Evaluation of congenital heart disease by cine magnetic resonance imaging (MRI)

    SciTech Connect

    Feiglin, D.H.I.; Moodie, D.S.; O'Donnell, J.K.; Go, R.T.; Sterba, R.; MacIntyre, W.J.

    1985-05-01

    The authors studied 11 adult patients (pts) with atrial septal defect (ASD) and 4 adult pts with ventricular septal defect (VSD) using cine magnetic resonance. All studies were performed using a .6T superconducting magnet with ECG gating and electronic axial rotation when appropriate. Repeated multislice image with no change in physiologic delay of the spin echo pulse sequence, but varying the time by offsetting one slice at each imaging stage allowed for an N x N collection of data where N is the number of slices in one collection set and is equal to the number of sets collected. Algebraic manipulation of the T1 weighted images (TE=30mSec TRcine dynamic display. This technique provides multitime views of each slice and allows for greater appreciation of right atrial enlargement, right ventricular hypertrophy and dilation, and imaging of the atrial septum than does conventional MRI. Using this technique, the authors have identified both atrial and ventricular septal defects in all pts preoperatively and have noted an intact atrial septum following surgery. Standard MRI produced 4 false positive studies postoperatively because only 1 phase of the cardiac cycle was reviewed. Cine MRI allows better identification of septal defects than standard static acquisitions. The cine technique also provides better definition and delineation of right sided abnormalities which are maximized when viewed in a cardiac major axis obtained by electronic axial rotation.

  20. Assessment of Bladder Motion for Clinical Radiotherapy Practice Using Cine-Magnetic Resonance Imaging

    SciTech Connect

    McBain, Catherine A.; Khoo, Vincent S.; Buckley, David L.; Sykes, Jonathan S.; Green, Melanie M.; Cowan, Richard A.; Hutchinson, Charles E.; Moore, Christopher J.; Price, Patricia M.

    2009-11-01

    Purpose: Organ motion is recognized as the principal source of inaccuracy in bladder radiotherapy (RT), but there is currently little information on intrafraction bladder motion. Methods and Materials: We used cine-magnetic resonance imaging (cine-MRI) to study bladder motion relevant to intrafraction RT delivery. On two occasions, a 28 minute cine-MRI sequence was acquired from 10 bladder cancer patients and 5 control participants immediately after bladder emptying, after abstinence from drinking for the preceding hour. From the resulting cine sequences, bladder motion was subjectively assessed. To quantify bladder motion, the bladder was contoured in imaging volume sets at 0, 14, and 28 min to measure changes to bladder volumes, wall displacements, and center of gravity (COG) over time. Results: The dominant source of bladder motion during imaging was bladder filling (up to 101% volume increase); rectal and small bowel movements were transient, with minimal impact. Bladder volume changes were similar for all participants. However for bladder cancer patients, wall displacements were larger (up to 58 mm), less symmetrical, and more variable compared with nondiseased control bladders. Conclusions: Significant and individualized intrafraction bladder wall displacements may occur during bladder RT delivery. This important source of inaccuracy should be incorporated into treatment planning and verification.

  1. An evaluation of cine-mode 3D portal image dosimetry for Volumetric Modulated Arc Therapy

    NASA Astrophysics Data System (ADS)

    Ansbacher, W.; Swift, C.-L.; Greer, P. B.

    2010-11-01

    We investigated cine-mode portal imaging on a Varian Trilogy accelerator and found that the linearity and other dosimetric properties are sufficient for 3D dose reconstruction as used in patient-specific quality assurance for VMAT (RapidArc) treatments. We also evaluated the gantry angle label in the portal image file header as a surrogate for the true imaged angle. The precision is only just adequate for the 3D evaluation method chosen, as discrepancies of 2° were observed.

  2. An insulin based model to explain changes and interactions in human breath-holding.

    PubMed

    Dangmann, Rosita

    2015-06-01

    Until now oxygen was thought to be the leading factor of hypoxic conditions. Whereas now it appears that insulin is the key regulator of hypoxic conditions. Insulin seems to regulate the redox state of the organism and to determine the breakpoint of human breath-holding. This new hypoxia-insulin hypotheses might have major clinical relevance. Besides the clinical relevance, this hypothesis could explain, for the first time, why the training of the diaphragm, among other factors, results in an increase in breath-holding performance. Elite freedivers/apnea divers are able to reach static breath-holding times to over 6 min. Untrained persons exhibit an unpleasant feeling after more or less a minute. Breath-holding is stopped at the breakpoint. The partial oxygen pressure as well as the carbon dioxide pressure failed to directly influence the breakpoint in earlier studies. The factors that contribute to the breakpoint are still under debate. Under hypoxic conditions the organism needs more glucose, because it changes from the oxygen consuming pentose phosphate (36 ATP/glucose molecule) to the anaerobic glycolytic pathway (2ATP/glucose molecule). Hence insulin, as it promotes the absorption of glucose, is set in the center of interest regarding hypoxic conditions. This paper provides an insulin based model that could explain the changes and interactions in human breath-holding. The correlation between hypoxia and reactive oxygen species (ROS) and their influence on the sympathetic nerve system and hypoxia-inducible factor 1 alpha (HIF-1α) is dealt with. It reviews as well the direct interrelation of HIF-1α and insulin. The depression of insulin secretion through the vagus nerve activation via inspiration is discussed. Furthermore the paper describes the action of insulin on the carotid bodies and the diaphragm and therefore a possible role in respiration pattern. Freedivers that go over the breakpoint of breath-holding could exhibit seizures and thus the effect of

  3. Algebraic Reconstruction Technique (ART) for parallel imaging reconstruction of undersampled radial data: Application to cardiac cine

    PubMed Central

    Li, Shu; Chan, Cheong; Stockmann, Jason P.; Tagare, Hemant; Adluru, Ganesh; Tam, Leo K.; Galiana, Gigi; Constable, R. Todd; Kozerke, Sebastian; Peters, Dana C.

    2014-01-01

    Purpose To investigate algebraic reconstruction technique (ART) for parallel imaging reconstruction of radial data, applied to accelerated cardiac cine. Methods A GPU-accelerated ART reconstruction was implemented and applied to simulations, point spread functions (PSF) and in twelve subjects imaged with radial cardiac cine acquisitions. Cine images were reconstructed with radial ART at multiple undersampling levels (192 Nr x Np = 96 to 16). Images were qualitatively and quantitatively analyzed for sharpness and artifacts, and compared to filtered back-projection (FBP), and conjugate gradient SENSE (CG SENSE). Results Radial ART provided reduced artifacts and mainly preserved spatial resolution, for both simulations and in vivo data. Artifacts were qualitatively and quantitatively less with ART than FBP using 48, 32, and 24 Np, although FBP provided quantitatively sharper images at undersampling levels of 48-24 Np (all p<0.05). Use of undersampled radial data for generating auto-calibrated coil-sensitivity profiles resulted in slightly reduced quality. ART was comparable to CG SENSE. GPU-acceleration increased ART reconstruction speed 15-fold, with little impact on the images. Conclusion GPU-accelerated ART is an alternative approach to image reconstruction for parallel radial MR imaging, providing reduced artifacts while mainly maintaining sharpness compared to FBP, as shown by its first application in cardiac studies. PMID:24753213

  4. Pulmonary oedema in breath-hold diving: an unusual presentation and computed tomography findings.

    PubMed

    Gempp, Emmanuel; Sbardella, Fabrice; Cardinale, Mickael; Louge, Pierre

    2013-09-01

    Haemoptysis and pulmonary oedema following deep breath-hold diving have been described in recent years. We describe the case of a 33-year-old healthy military diver who presented symptoms suggestive of pulmonary oedema after two breathhold dives, the first lasting 0.5-1 min and the second 1-2 min, to 6 metres' depth in the sea. The diagnosis was promptly confirmed with chest computed tomography showing bilateral interstitial infiltrates in the upper regions of the lungs. To our knowledge, this is the first report to document pulmonary oedema in this setting of shallow breath-hold diving with atypical radiological presentation. A definite mechanism for this specific distribution of lung injury remains unclear. PMID:24122192

  5. Review of deep inspiration breath-hold techniques for the treatment of breast cancer

    PubMed Central

    Latty, Drew; Stuart, Kirsty E; Wang, Wei; Ahern, Verity

    2015-01-01

    Radiation treatment to the left breast is associated with increased cardiac morbidity and mortality. The deep inspiration breath-hold technique (DIBH) can decrease radiation dose delivered to the heart and this may facilitate the treatment of the internal mammary chain nodes. The aim of this review is to critically analyse the literature available in relation to breath-hold methods, implementation, utilisation, patient compliance, planning methods and treatment verification of the DIBH technique. Despite variation in the literature regarding the DIBH delivery method, patient coaching, visual feedback mechanisms and treatment verification, all methods of DIBH delivery reduce radiation dose to the heart. Further research is required to determine optimum protocols for patient training and treatment verification to ensure the technique is delivered successfully. PMID:26229670

  6. Review of deep inspiration breath-hold techniques for the treatment of breast cancer

    SciTech Connect

    Latty, Drew; Stuart, Kirsty E; Wang, Wei; Ahern, Verity

    2015-03-15

    Radiation treatment to the left breast is associated with increased cardiac morbidity and mortality. The deep inspiration breath-hold technique (DIBH) can decrease radiation dose delivered to the heart and this may facilitate the treatment of the internal mammary chain nodes. The aim of this review is to critically analyse the literature available in relation to breath-hold methods, implementation, utilisation, patient compliance, planning methods and treatment verification of the DIBH technique. Despite variation in the literature regarding the DIBH delivery method, patient coaching, visual feedback mechanisms and treatment verification, all methods of DIBH delivery reduce radiation dose to the heart. Further research is required to determine optimum protocols for patient training and treatment verification to ensure the technique is delivered successfully.

  7. Hemoptysis provoked by voluntary diaphragmatic contractions in breath-hold divers.

    PubMed

    Kiyan, E; Aktas, S; Toklu, A S

    2001-12-01

    Pulmonary barotrauma of descent (lung squeeze) has been described in breath-hold divers when the lung volume becomes smaller than the residual volume (RV), with the effect of increased ambient pressure. However, the ratio between the total lung capacity and the RV is not the only factor that plays a role in the lung squeeze. Blood shift into the thorax is another important factor. We report three cases of hemoptysis in breath-hold divers who dove for spear fishing in shallower depths than usual. All of the divers performed voluntary diaphragmatic contractions at the beginning of their ascent, while their mouths and noses were closed. We suggest that the negative intrathoracic pressure due to the forced attempt to breathe in with voluntary diaphragmatic contractions contributes to alveolar hemorrhage, since it may damage the pulmonary capillaries. PMID:11742946

  8. Horses Auto-Recruit Their Lungs by Inspiratory Breath Holding Following Recovery from General Anaesthesia

    PubMed Central

    Mosing, Martina; Waldmann, Andreas D.; MacFarlane, Paul; Iff, Samuel; Auer, Ulrike; Bohm, Stephan H.; Bettschart-Wolfensberger, Regula; Bardell, David

    2016-01-01

    This study evaluated the breathing pattern and distribution of ventilation in horses prior to and following recovery from general anaesthesia using electrical impedance tomography (EIT). Six horses were anaesthetised for 6 hours in dorsal recumbency. Arterial blood gas and EIT measurements were performed 24 hours before (baseline) and 1, 2, 3, 4, 5 and 6 hours after horses stood following anaesthesia. At each time point 4 representative spontaneous breaths were analysed. The percentage of the total breath length during which impedance remained greater than 50% of the maximum inspiratory impedance change (breath holding), the fraction of total tidal ventilation within each of four stacked regions of interest (ROI) (distribution of ventilation) and the filling time and inflation period of seven ROI evenly distributed over the dorso-ventral height of the lungs were calculated. Mixed effects multi-linear regression and linear regression were used and significance was set at p<0.05. All horses demonstrated inspiratory breath holding until 5 hours after standing. No change from baseline was seen for the distribution of ventilation during inspiration. Filling time and inflation period were more rapid and shorter in ventral and slower and longer in most dorsal ROI compared to baseline, respectively. In a mixed effects multi-linear regression, breath holding was significantly correlated with PaCO2 in both the univariate and multivariate regression. Following recovery from anaesthesia, horses showed inspiratory breath holding during which gas redistributed from ventral into dorsal regions of the lungs. This suggests auto-recruitment of lung tissue which would have been dependent and likely atelectic during anaesthesia. PMID:27331910

  9. Underwater study of arterial blood pressure in breath-hold divers.

    PubMed

    Sieber, Arne; L'abbate, Antonio; Passera, Mirko; Garbella, Erika; Benassi, Antonio; Bedini, Remo

    2009-11-01

    Knowledge regarding arterial blood pressure (ABP) values during breath-hold diving is scanty. It derives from a few reports of measurements performed at the water's surface, showing slight or no increase in ABP, and from a single study of two simulated deep breath-hold dives in a hyperbaric chamber. Simulated dives showed an increase in ABP to values considered life threatening by standard clinical criteria. For the first time, using a novel noninvasive subaquatic sphygmomanometer, we successfully measured ABP in 10 healthy elite breath-hold divers at a depth of 10 m of freshwater (mfw). ABP was measured in dry conditions, at the surface (head-out immersion), and twice at a depth of 10 mfw. Underwater measurements of ABP were obtained in all subjects. Each measurement lasted 50-60 s and was accomplished without any complications or diver discomfort. In the 10 subjects as a whole, mean ABP values were 124/93 mmHg at the surface and 123/94 mmHg at a depth of 10 mfw. No significant statistical differences were found when blood pressure measurements at the water surface were compared with breath-hold diving conditions at a depth of 10 mfw. No systolic blood pressure values >140 mmHg or diastolic blood pressure values >115 mmHg were recorded. In conclusion, direct measurements of ABP during apnea diving showed no or only mild increases in ABP. However, our results cannot be extended over environmental conditions different from those of the present study. PMID:19696356

  10. A survey of neurological decompression illness in commercial breath-hold divers (Ama) of Japan.

    PubMed

    Tamaki, Hideki; Kohshi, Kiyotaka; Ishitake, Tatsuya; Wong, Robert M

    2010-01-01

    A survey was conducted in the northern district of Yamaguchi, Japan to determine the relationship between neurological diving accidents and risk factors among commercial breath-hold divers (Ama). A questionnaire was distributed to 381 Ama divers who are members of the Ama diving union. We sought information on their dive practices (depth of single dive, single dive time, surface interval, length of dive shifts, lunch break) and the presence or absence of medical problems, such as hypertension, cardiac arrhythmia, diabetic mellitus and other issues. Of the 381 Ama divers, 173 responded (45%): 29 were Funado (assisted-descent using weights) and 144 Cachido (unassisted) divers. Twelve had experienced strokelike symptoms during or after repetitive breath-hold diving; 11 were assisted and one unassisted (Funado vs. Cachido). Only two of 12 divers with neurological diving accidents had musculoskeletal symptoms. Neurological events were significantly correlated with dive depth, dive time, and surface interval; however, they were not related to medical history. Neurological diving accidents are more likely to happen among assisted Ama divers than unassisted ones. Repetitive breath-hold diving with a deep dive depth, long dive time, and short surface interval predisposes divers to decompression illness, which characteristically manifests as cerebral stroke. PMID:20737928

  11. Dosimetric and clinical advantages of deep inspiration breath-hold (DIBH) during radiotherapy of breast cancer

    PubMed Central

    2013-01-01

    Background To investigate the potential dosimetric and clinical benefits of Deep Inspiration Breath-Hold (DIBH) technique during radiotherapy of breast cancer compared with Free Breathing (FB). Methods Eight left-sided breast cancer patients underwent a supervised breath hold during treatment. For each patient, two CT scans were acquired with and without breath hold, and virtual simulation was performed for conventional tangential fields, utilizing 6 or 15 MV photon fields. The resulting dose–volume histograms were calculated, and the volumes of heart/lung irradiated to given doses were assessed. The left anterior descending coronary artery (LAD) mean and maximum doses were calculated, together with tumour control probability (TCP) and normal tissue complication probabilities (NTCP) for lung and heart. Results For all patients a reduction of at least 16% in lung mean dose and at least 20% in irradiated pulmonary volumes was observed when DIBH was applied. Heart and LAD maximum doses were decreased by more than 78% with DIBH. The NTCP values for pneumonitis and long term cardiac mortality were also reduced by about 11% with DIBH. The NTCP values for pericarditis were zero for both DIBH and FB. Conclusion Delivering radiation in DIBH conditions the dose to the surrounding normal structures could be reduced, in particular heart, LAD and lung, due to increased distance between target and heart, and to reduced lung density. PMID:24423396

  12. Cardio-ventilatory responses to poikilocapnic hypoxia and hypercapnia in trained breath-hold divers.

    PubMed

    Costalat, Guillaume; Pichon, Aurélien; Coquart, Jeremy; Bauer, Fabrice; Lemaître, Frédéric

    2014-02-01

    Trained breath-hold divers (BHDs) are exposed to repeated bouts of intermittent hypoxia and hypercapnia during prolonged breath-holding. It has thus been hypothesized that their specific training may develop enhanced chemo-responsiveness to hypoxia associated with reduced ventilatory response to hypercapnia. Hypercapnic ventilatory responses (HCVR) and hypoxic ventilatory responses at rest (HVRr) and exercise (HVRe) were assessed in BHDs (n=7) and a control group of non-divers (NDs=7). Cardiac output (CO), stroke volume (SV) and heart rate (HR) were also recorded. BHDs presented carbon dioxide sensitivity similar to that of NDs (2.85±1.41 vs. 1.85±0.93Lmin(-1)mmHg(-1), p>0.05, respectively). However, both HVRr (+68%) and HVRe (+31%) were increased in BHDs. CO and HR reached lower values in BHDs than NDs during the hypoxic exercise test. These results suggest that the exposure to repeated bouts of hypoxia/hypercapnia frequently experienced by trained breath-hold divers only enhances their chemo-responsiveness to poikilocapnic hypoxia, without altering HCVR. PMID:24341998

  13. Interfractional Dose Variations in Intensity-Modulated Radiotherapy With Breath-Hold for Pancreatic Cancer

    SciTech Connect

    Nakamura, Mitsuhiro; Shibuya, Keiko; Nakamura, Akira; Shiinoki, Takehiro; Matsuo, Yukinori; Nakata, Manabu; Sawada, Akira; Mizowaki, Takashi; Hiraoka, Masahiro

    2012-04-01

    Purpose: To investigate the interfractional dose variations for intensity-modulated radiotherapy (RT) combined with breath-hold (BH) at end-exhalation (EE) for pancreatic cancer. Methods and Materials: A total of 10 consecutive patients with pancreatic cancer were enrolled. Each patient was fixed in the supine position on an individualized vacuum pillow with both arms raised. Computed tomography (CT) scans were performed before RT, and three additional scans were performed during the course of chemoradiotherapy using a conventional RT technique. The CT data were acquired under EE-BH conditions (BH-CT) using a visual feedback technique. The intensity-modulated RT plan, which used five 15-MV coplanar ports, was designed on the initial BH-CT set with a prescription dose of 39 Gy at 2.6 Gy/fraction. After rigid image registration between the initial and subsequent BH-CT scans, the dose distributions were recalculated on the subsequent BH-CT images under the same conditions as in planning. Changes in the dose-volume metrics of the gross tumor volume (GTV), clinical target volume (CTV = GTV + 5 mm), stomach, and duodenum were evaluated. Results: For the GTV and clinical target volume (CTV), the 95th percentile of the interfractional variations in the maximal dose, mean dose, dose covering 95% volume of the region of structure, and percentage of the volume covered by the 90% isodose line were within {+-}3%. Although the volume covered by the 39 Gy isodose line for the stomach and duodenum did not exceed 0.1 mL at planning, the volume covered by the 39 Gy isodose line for these structures was up to 11.4 cm{sup 3} and 1.8 cm{sup 3}, respectively. Conclusions: Despite variations in the gastrointestinal state and abdominal wall position at EE, the GTV and CTV were mostly ensured at the planned dose, with the exception of 1 patient. Compared with the duodenum, large variations in the stomach volume receiving high-dose radiation were observed, which might be beyond the

  14. High spatial and temporal resolution retrospective cine cardiovascular magnetic resonance from shortened free breathing real-time acquisitions

    PubMed Central

    2013-01-01

    Background Cine cardiovascular magnetic resonance (CMR) is challenging in patients who cannot perform repeated breath holds. Real-time, free-breathing acquisition is an alternative, but image quality is typically inferior. There is a clinical need for techniques that achieve similar image quality to the segmented cine using a free breathing acquisition. Previously, high quality retrospectively gated cine images have been reconstructed from real-time acquisitions using parallel imaging and motion correction. These methods had limited clinical applicability due to lengthy acquisitions and volumetric measurements obtained with such methods have not previously been evaluated systematically. Methods This study introduces a new retrospective reconstruction scheme for real-time cine imaging which aims to shorten the required acquisition. A real-time acquisition of 16-20s per acquired slice was inputted into a retrospective cine reconstruction algorithm, which employed non-rigid registration to remove respiratory motion and SPIRiT non-linear reconstruction with temporal regularization to fill in missing data. The algorithm was used to reconstruct cine loops with high spatial (1.3-1.8 × 1.8-2.1 mm2) and temporal resolution (retrospectively gated, 30 cardiac phases, temporal resolution 34.3 ± 9.1 ms). Validation was performed in 15 healthy volunteers using two different acquisition resolutions (256 × 144/192 × 128 matrix sizes). For each subject, 9 to 12 short axis and 3 long axis slices were imaged with both segmented and real-time acquisitions. The retrospectively reconstructed real-time cine images were compared to a traditional segmented breath-held acquisition in terms of image quality scores. Image quality scoring was performed by two experts using a scale between 1 and 5 (poor to good). For every subject, LAX and three SAX slices were selected and reviewed in the random order. The reviewers were blinded to the reconstruction approach and

  15. Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes

    NASA Astrophysics Data System (ADS)

    Bjerre, Troels; Crijns, Sjoerd; Rosenschöld, Per Munck af; Aznar, Marianne; Specht, Lena; Larsen, Rasmus; Keall, Paul

    2013-07-01

    The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path. For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm for a translation of 39.9 mm. We have demonstrated how interleaved acquired, orthogonal cine-MRI planes can be used for online tracking of soft-tissue target volumes.

  16. Three-dimensional MRI-linac intra-fraction guidance using multiple orthogonal cine-MRI planes.

    PubMed

    Bjerre, Troels; Crijns, Sjoerd; af Rosenschöld, Per Munck; Aznar, Marianne; Specht, Lena; Larsen, Rasmus; Keall, Paul

    2013-07-21

    The introduction of integrated MRI-radiation therapy systems will offer live intra-fraction imaging. We propose a feasible low-latency multi-plane MRI-linac guidance strategy. In this work we demonstrate how interleaved acquired, orthogonal cine-MRI planes can be used for low-latency tracking of the 3D trajectory of a soft-tissue target structure. The proposed strategy relies on acquiring a pre-treatment 3D breath-hold scan, extracting a 3D target template and performing template matching between this 3D template and pairs of orthogonal 2D cine-MRI planes intersecting the target motion path. For a 60 s free-breathing series of orthogonal cine-MRI planes, we demonstrate that the method was capable of accurately tracking the respiration related 3D motion of the left kidney. Quantitative evaluation of the method using a dataset designed for this purpose revealed a translational error of 1.15 mm for a translation of 39.9 mm. We have demonstrated how interleaved acquired, orthogonal cine-MRI planes can be used for online tracking of soft-tissue target volumes. PMID:23807514

  17. Cardiac Motion During Deep-Inspiration Breath-Hold: Implications for Breast Cancer Radiotherapy

    SciTech Connect

    Wang Xiaochun; Pan Tinsu; Pinnix, Chelsea; Zhang, Sean X.; Salehpour, Mohammad; Sun, Tzouh Liang; Gladish, Gregory; Strom, Eric A.; Perkins, George H.; Tereffe, Welela; Woodward, Wendy; Hoffman, Karen E.; Buchholz, Thomas A.; Yu, T. Kuan

    2012-02-01

    Purpose: Many patients with left-sided breast cancer receive adjuvant radiotherapy during deep-inspiration breath hold (DIBH) to minimize radiation exposure to the heart. We measured the displacement of the left anterior descending artery (LAD) and heart owing to cardiac motion during DIBH, relative to the standard tangential fields for left breast cancer radiotherapy. Methods and Materials: A total of 20 patients who had undergone computed tomography-based coronary angiography with retrospective electrocardiographic gating were randomly selected for the present study. The patients underwent scanning during DIBH to control the influence of respiration on cardiac motion. Standard medial and lateral tangential fields were placed, and the LADs were contoured on the systolic- and diastolic-phase computed tomography data sets by the clinicians. Displacement of the LAD during cardiac contractions was calculated in three directions: toward the posterior edge of the treatment fields, left-right, and anteroposterior. Displacement of the entire heart was measured on the maximal and minimal intensity projection computed tomography images. Results: The mean displacement of the LAD from cardiac contraction without the influence of respiration for 20 patients was 2.3 mm (range, 0.7-3.8) toward the posterior edge of the treatment fields, 2.6 mm (range, 1.0-6.8) in the left-right direction, and 2.3 mm (range, 0.6-6.5) in the anteroposterior direction. At least 30% of the LAD volume was displaced >5 mm in any direction in 2 patients (10%), and <10% of the LAD volume was displaced >5 mm in 10 patients (50%). The extent of displacement of the heart periphery during cardiac motion was negligible near the treatment fields. Conclusions: Displacement of the heart periphery near the treatment fields was negligible during DIBH; however, displacement of the LAD from cardiac contraction varied substantially between and within patients. We recommend maintaining {>=}5 mm of distance between

  18. Fourier modeling of the BOLD response to a breath-hold task: Optimization and reproducibility.

    PubMed

    Pinto, Joana; Jorge, João; Sousa, Inês; Vilela, Pedro; Figueiredo, Patrícia

    2016-07-15

    Cerebrovascular reactivity (CVR) reflects the capacity of blood vessels to adjust their caliber in order to maintain a steady supply of brain perfusion, and it may provide a sensitive disease biomarker. Measurement of the blood oxygen level dependent (BOLD) response to a hypercapnia-inducing breath-hold (BH) task has been frequently used to map CVR noninvasively using functional magnetic resonance imaging (fMRI). However, the best modeling approach for the accurate quantification of CVR maps remains an open issue. Here, we compare and optimize Fourier models of the BOLD response to a BH task with a preparatory inspiration, and assess the test-retest reproducibility of the associated CVR measurements, in a group of 10 healthy volunteers studied over two fMRI sessions. Linear combinations of sine-cosine pairs at the BH task frequency and its successive harmonics were added sequentially in a nested models approach, and were compared in terms of the adjusted coefficient of determination and corresponding variance explained (VE) of the BOLD signal, as well as the number of voxels exhibiting significant BOLD responses, the estimated CVR values, and their test-retest reproducibility. The brain average VE increased significantly with the Fourier model order, up to the 3rd order. However, the number of responsive voxels increased significantly only up to the 2nd order, and started to decrease from the 3rd order onwards. Moreover, no significant relative underestimation of CVR values was observed beyond the 2nd order. Hence, the 2nd order model was concluded to be the optimal choice for the studied paradigm. This model also yielded the best test-retest reproducibility results, with intra-subject coefficients of variation of 12 and 16% and an intra-class correlation coefficient of 0.74. In conclusion, our results indicate that a Fourier series set consisting of a sine-cosine pair at the BH task frequency and its two harmonics is a suitable model for BOLD-fMRI CVR measurements

  19. Inter- and Intrafraction Variability in Liver Position in Non-Breath-Hold Stereotactic Body Radiotherapy

    SciTech Connect

    Case, Robert B.; Sonke, Jan-Jakob; Moseley, Douglas J.; Kim, John; Brock, Kristy K.; Dawson, Laura A.

    2009-09-01

    Purpose: The inter- and intrafraction variability of liver position was assessed in patients with liver cancer treated with kilovoltage cone-beam computed tomography (CBCT)-guided stereotactic body radiotherapy. Methods and Materials: A total of 314 CBCT scans obtained in the treatment position immediately before and after each fraction were evaluated from 29 patients undergoing six-fraction, non-breath-hold stereotactic body radiotherapy for unresectable liver cancer. Off-line, the CBCT scans were sorted into 10 bins, according to the phase of respiration. The liver position (relative to the vertebral bodies) was measured using rigid alignment of the exhale CBCT liver with the exhale planning CT liver, following the alignment of the vertebrae. The interfraction liver position change was measured by comparing the pretreatment CBCT scans, and the intrafraction change was measured from the CBCT scans obtained immediately before and after each fraction. Results: The mean amplitude of liver motion for all patients was 1.8 mm (range, 0.1-5.7), 8.0 mm (range, 0.1-18.8), and 4.3 mm (range 0.1-12.1) in the medial-lateral (ML), craniocaudal (CC), and anteroposterior (AP) directions, respectively. The mean absolute ML, CC, and AP interfraction changes in liver position were 2.0 mm (90th percentile, 4.2), 3.5 mm (90th percentile, 7.3), and 2.3 mm (90th percentile, 4.7). The mean absolute intrafraction ML, CC, and AP changes were 1.3 mm (90th percentile, 2.9), 1.6 mm (90th percentile, 3.6), and 1.5 mm (90th percentile, 3.1), respectively. The interfraction changes were significantly larger than the intrafraction changes, with a CC systematic error of 2.9 and 1.1 mm, respectively. The intraobserver reproducibility ({sigma}, n = 29 fractions) was 1.3 mm in the ML, 1.4 mm in the CC, and 1.6 mm in the AP direction. Conclusion: Interfraction liver position changes relative to the vertebral bodies are an important source of geometric uncertainty, providing a rationale for

  20. Pneumomediastinum or lung damage in breath-hold divers from different mechanisms: a report of three cases.

    PubMed

    Toklu, Akin Savaş; Erelel, Mustafa; Arslan, Abdullah

    2013-12-01

    Normally pulmonary over-inflation is not an issue during breath-hold diving, in contrast to lung squeeze. Compared with compressed air diving, pulmonary barotrauma is rare in breath-hold diving. Several mechanisms can lead to an increase in intrathoracic pressure in breath-hold diving that may cause alveolar rupture. Here we report three cases of pulmonary barotrauma in breath-hold diving. Using high-resolution chest tomography, bullous damage in Case 1, and pneumomediastinum in Cases 2 and 3 were detected. Transient neurological symptoms in Cases 1 and 2 suggested cerebral arterial gas embolism. The mechanisms that caused intrapulmonary overpressure were, respectively, lung packing ('buccal pumping'), considerable effort and straining at depth, and breathing compressed air at depth and ascending without exhaling. All three cases recovered without specific treatment such as recompression. PMID:24510331

  1. Circulating bubbles and breath-hold underwater fishing divers: a two-dimensional echocardiography and continuous wave Doppler study.

    PubMed

    Boussuges, A; Abdellaoui, S; Gardette, B; Sainty, J M

    1997-01-01

    Since the 1960s, decompression illness after breath-hold diving has been widely debated. The aim of this study was to detect circulating bubbles after breath-hold diving in underwater fishing divers. We used continuous Doppler (DUG, COMEX Pro) and transthoracic two-dimensional (2D) echocardiography (Kontron Sigma 1). This study was conducted during a training course organized by the French Federation of Subaquatic Sports at Minorca (Balearic Islands). Ten breath-hold divers performed repeated breath-hold dives for periods ranging from 2 to 6 h [mean maximum depth 35 meters of seawater (msw)]. A dive computer (Maestro Pro Beuchat, analyst PC interface) was used to record diving patterns. No circulating bubbles were detected in the right heart cavities (2D echocardiography) or in the pulmonary artery (continuous Doppler). However, this study had some limits: only 10 subjects were studied and the earliest detection was 3 min after immersion, further studies will thus be required. PMID:9444062

  2. Myocardial 3D strain calculation by combining cine DENSE and cine SENC imaging

    PubMed Central

    Hess, Aaron T.; Zhong, Xiaodong; Spottiswoode, Bruce. S.; Epstein, Frederick. H.; Meintjes, Ernesta M.

    2009-01-01

    Three-dimensional (3D) strain maps of the myocardium provide a coordinate-system-independent quantification of myocardial deformation and kinematics. We combine two MRI techniques, displacement encoding with stimulated echoes (DENSE) and strain encoding (SENC), to fully formulate a 3D strain map in a single slice of myocardium. The method utilizes two-dimensional DENSE in-plane displacement measurements in two adjacent slices in conjunction with a single SENC through-plane strain measure to calculate the 3D strain tensor. Six volunteers were imaged and the technique demonstrated 3D strain measures in all volunteers that are consistent with those reported in the literature from 3D tagging. The mean peak strain (+/− standard deviation) for six healthy volunteers for the first, second and third principal strains are 0.42 +/−0.11, −0.10 +/−0.03, and −0.21 +/−0.02, respectively. These results show that this technique is capable of reliably quantifying 3D cardiac strain. PMID:19322795

  3. Quantifying the Reproducibility of Heart Position During Treatment and Corresponding Delivered Heart Dose in Voluntary Deep Inhalation Breath Hold for Left Breast Cancer Patients Treated With External Beam Radiotherapy

    SciTech Connect

    McIntosh, Alyson; Shoushtari, Asal N.; Benedict, Stanley H.; Read, Paul W.; Wijesooriya, Krishni

    2011-11-15

    Purpose: Voluntary deep inhalation breath hold (VDIBH) reduces heart dose during left breast irradiation. We present results of the first study performed to quantify reproducibility of breath hold using bony anatomy, heart position, and heart dose for VDIBH patients at treatment table. Methods and Materials: Data from 10 left breast cancer patients undergoing VDIBH whole-breast irradiation were analyzed. Two computed tomography (CT) scans, free breathing (FB) and VDIBH, were acquired to compare dose to critical structures. Pretreatment weekly kV orthogonal images and tangential ports were acquired. The displacement difference from spinal cord to sternum across the isocenter between coregistered planning Digitally Reconstructed Radiographs (DRRs) and kV imaging of bony thorax is a measure of breath hold reproducibility. The difference between bony coregistration and heart coregistration was the measured heart shift if the patient is aligned to bony anatomy. Results: Percentage of dose reductions from FB to VDIBH: mean heart dose (48%, SD 19%, p = 0.002), mean LAD dose (43%, SD 19%, p = 0.008), and maximum left anterior descending (LAD) dose (60%, SD 22%, p = 0.008). Average breath hold reproducibility using bony anatomy across the isocenter along the anteroposterior (AP) plane from planning to treatment is 1 (range, 0-3; SD, 1) mm. Average heart shifts with respect to bony anatomy between different breath holds are 2 {+-} 3 mm inferior, 1 {+-} 2 mm right, and 1 {+-} 3 mm posterior. Percentage dose changes from planning to delivery: mean heart dose (7%, SD 6%); mean LAD dose, ((9%, SD 7%)S, and maximum LAD dose, (11%, SD 11%) SD 11%, p = 0.008). Conclusion: We observed excellent three-dimensional bony registration between planning and pretreatment imaging. Reduced delivered dose to heart and LAD is maintained throughout VDIBH treatment.

  4. Optimization of parameter settings in cine-MR imaging for diagnosis of swallowing.

    PubMed

    Ohkubo, Mai; Higaki, Takuo; Nishikawa, Keiichi; Otonari-Yamamoto, Mika; Sugiyama, Tetsuya; Ishida, Ryo; Wako, Mamoru; Sano, Tsukasa

    2014-01-01

    Videofluorography is frequently used to evaluate swallowing and is considered the "gold standard" among imaging modalities. This modality, however, has several disadvantages, including radiation exposure and limitations in the detection of soft tissues. Conversely, magnetic resonance imaging (MRI) offers excellent contrast resolution in soft tissue without radiation exposure. A major drawback of MRI in evaluating swallowing, however, is that temporal resolution is poor. The aim of this study was to investigate a new cine-MRI modality. Imaging parameters were optimized and the efficacy of this new technique is discussed. Three techniques for speeding up MRI were combined: true fast imaging with steady state precession, generalized auto-calibrating partially parallel acquisition, and key-hole imaging. The effects of the receiver coils used, receiving bandwidth, slice thickness, and flip angle on each image were determined. The optimal imaging parameters obtained comprised a reduction factor of 2, receiving bandwidth of 1,000 Hz/pixel (repetition time of 151.7 milliseconds and echo time of 1.4 milliseconds), flip angle of 50°, and slice thickness of 6 mm. Neck and spine coils were used. Under these conditions, the new cine-MR imaging technique investigated showed a temporal resolution of 0.1 sec/slice (10 frames/sec). Even with optimized parameter settings, this technique did not allow a true temporal resolution of 30 frames/sec by a large margin. Motion artifacts persisted. Further study is needed on how to speed up this technique. PMID:25212558

  5. Spontaneous pneumomediastinum in an 11-year-old boy after a shallow breath-hold dive.

    PubMed

    Laitila, Maija; Eskola, Vesa

    2013-12-01

    Spontaneous pneumomediastinum is caused by pulmonary barotrauma due to transiently increased intra-alveolar and intra-bronchial pressure. The most frequent triggers of spontaneous pneumomediastinum in children are asthma and manoeuvres creating forced expiration. It has been rarely associated with breath-hold diving. Chest pain and dyspnoea are the main symptoms, and the diagnosis can be confirmed by chest X-ray. The treatment of choice is oxygen, analgesics and monitoring the patient. The recurrence rate is low. The main differential diagnoses of spontaneous pneumomediastinum are oesophageal perforation and pericarditis. We report a case of an 11-year-old boy with no substantial medical history, who tried to breath-hold in shallow water for as long as possible. After diving, he felt dyspnoea and chest pain. Chest X-ray revealed pneumomediastinum and subcutaneous emphysema. The patient was admitted to the PICU for observation and was discharged after two days' follow up. Spontaneous pneumomediastinum in children may be more common than thus far acknowledged. It requires a high index of suspicion and should be considered in all children with acute chest pain. PMID:24510332

  6. Comparison of cerebral vascular reactivity measures obtained using breath-holding and CO2 inhalation.

    PubMed

    Tancredi, Felipe B; Hoge, Richard D

    2013-07-01

    Stimulation of cerebral vasculature using hypercapnia has been widely used to study cerebral vascular reactivity (CVR), which can be expressed as the quantitative change in cerebral blood flow (CBF) per mm Hg change in end-tidal partial pressure of CO2 (PETCO2). We investigate whether different respiratory manipulations, with arterial spin labeling used to measure CBF, lead to consistent measures of CVR. The approaches included: (1) an automated system delivering variable concentrations of inspired CO2 for prospective targeting of PETCO2, (2) administration of a fixed concentration of CO2 leading to subject-dependent changes in PETCO2, (3) a breath-hold (BH) paradigm with physiologic modeling of CO2 accumulation, and (4) a maneuver combining breath-hold and hyperventilation. When CVR was expressed as the percent change in CBF per mm Hg change in PETCO2, methods 1 to 3 gave consistent results. The CVR values using method 4 were significantly lower. When CVR was expressed in terms of the absolute change in CBF (mL/100 g per minute per mm Hg), greater discrepancies became apparent: methods 2 and 3 gave lower absolute CVR values compared with method 1, and the value obtained with method 4 was dramatically lower. Our findings indicate that care must be taken to ensure that CVR is measured over the linear range of the CBF-CO2 dose-response curve, avoiding hypocapnic conditions. PMID:23571282

  7. Regulation of brain blood flow and oxygen delivery in elite breath-hold divers.

    PubMed

    Willie, Christopher K; Ainslie, Philip N; Drvis, Ivan; MacLeod, David B; Bain, Anthony R; Madden, Dennis; Maslov, Petra Zubin; Dujic, Zeljko

    2015-01-01

    The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n=17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) while breathing. End-apnea PaO2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF. PMID:25370857

  8. Cardiovascular changes during underwater static and dynamic breath-hold dives in trained divers.

    PubMed

    Breskovic, Toni; Uglesic, Lovro; Zubin, Petra; Kuch, Benjamin; Kraljevic, Jasenka; Zanchi, Jaksa; Ljubkovic, Marko; Sieber, Arne; Dujic, Zeljko

    2011-09-01

    Limited information exists concerning arterial blood pressure (BP) changes in underwater breath-hold diving. Simulated chamber dives to 50 m of freshwater (mfw) reported very high levels of invasive BP in two divers during static apnea (SA), whereas a recent study using a noninvasive subaquatic sphygmomanometer reported unchanged or mildly increased values at 10 m SA dive. In this study we investigated underwater BP changes during not only SA but, for the first time, dynamic apnea (DA) and shortened (SHT) DA in 16 trained breath-hold divers. Measurements included BP (subaquatic sphygmomanometer), ECG, and pulse oxymetry (arterial oxygen saturation, SpO₂, and heart rate). BP was measured during dry conditions, at surface fully immersed (SA), and at 2 mfw (DA and SHT DA), whereas ECG and pulse oxymetry were measured continuously. We have found significantly higher mean arterial pressure (MAP) values in SA (∼40%) vs. SHT DA (∼30%). Postapneic recovery of BP was slightly slower after SHT DA. Significantly higher BP gain (mmHg/duration of apnea in s) was found in SHT DA vs. SA. Furthermore, DA attempts resulted in faster desaturation vs. SA. In conclusion, we have found moderate increases in BP during SA, DA, and SHT DA. These cardiovascular changes during immersed SA and DA are in agreement with those reported for dry SA and DA. PMID:21719730

  9. Heart rate and blood pressure time courses during prolonged dry apnoea in breath-hold divers.

    PubMed

    Perini, Renza; Tironi, Adelaide; Gheza, Alberto; Butti, Ferdinando; Moia, Christian; Ferretti, Guido

    2008-09-01

    To define the dynamics of cardiovascular adjustments to apnoea, beat-to-beat heart rate (HR) and blood pressure and arterial oxygen saturation (SaO(2)) were recorded during prolonged breath-holding in air in 20 divers. Apnoea had a mean duration of 210 +/- 70 s. In all subjects, HR attained a value 14 beats min(-1) lower than control within the initial 30 s (phase I). HR did not change for the following 2-2.5 min (phase II). Then, nine subjects interrupted the apnoea (group A), whereas 11 subjects (group B) could prolong the breath-holding for about 100 s, during which HR continuously decreased (phase III). In both groups, mean blood pressure was 8 mmHg above control at the end of phase I; it then further increased by additional 12 mmHg at the end of the apnoea. In both groups, SaO(2) did not change in the initial 100-140 s of apnoea; then, it decreased to 95% at the end of phase II. In group B, SaO(2) further diminished to 84% at the end of phase III. A typical pattern of cardiovascular readjustments was identified during dry apnoea. This pattern was not compatible with a role for baroreflexes in phase I and phase II. Further readjustment in group B may imply a role for both baroreflexes and chemoreflexes. Hypothesis has been made that the end of phase II corresponds to physiological breakpoint. PMID:18496707

  10. Barotraumatic orbital emphysema of rhinogenic origin in a breath-hold diver: a case report.

    PubMed

    Bolognini, A; Delehaye, E; Cau, M; Cosso, L

    2008-01-01

    Orbital emphysema is a well-recognized complication of fractures involving the orbit. Commonly, it occurs when high pressure develops in nasal cavity as during nose blowing, coughing or Valsalva's maneuver and usually occurs in the subcutaneous tissues. We report the case of a young breath-hold diver who developed spontaneous, non compressive orbital emphysema during underwater fishing, with a maximal depth of 25-30 meters in the Sardinian sea. He was otherwise healthy, without previous cranio-facial trauma and nasosinusal diseases or surgery were not present in the history. When he was referred to our attention the patient presented right eyelid ptosis but diplopia and vision impairment were absent. Computer tomography scans showed subcutaneous air in the right upper eyelid and around the eyeball, particularly near the orbit's roof but optic nerve area, intraconal, was free of air. A dehiscence in lamina papyracea was evident. In our opinion, this has been the point of air entry into the orbit. A supportive therapy was advised and two weeks later the emphysema was recovered completely and the subject was symptoms free. The literature has been revised and to our knowledge no previous cases of barotraumatic orbital emphysema, in a breath-hold diver, are referred. PMID:18619111

  11. Presumed Arterial Gas Embolism After Breath-Hold Diving in Shallow Water.

    PubMed

    Harmsen, Stefani; Schramm, Dirk; Karenfort, Michael; Christaras, Andreas; Euler, Michael; Mayatepek, Ertan; Tibussek, Daniel

    2015-09-01

    Dive-related injuries are relatively common, but almost exclusively occur in recreational or scuba diving. We report 2 children with acute central nervous system complications after breath-hold diving. A 12-year-old boy presented with unilateral leg weakness and paresthesia after diving beneath the water surface for a distance of ∼25 m. After ascent, he suddenly felt extreme thoracic pain that resolved spontaneously. Neurologic examination revealed right leg weakness and sensory deficits with a sensory level at T5. Spinal MRI revealed a nonenhancing T2-hyperintense lesion in the central cord at the level of T1/T2 suggesting a spinal cord edema. A few weeks later, a 13-year-old girl was admitted with acute dizziness, personality changes, confusion, and headache. Thirty minutes before, she had practiced diving beneath the water surface for a distance of ∼25 m. After stepping out, she felt sudden severe thoracic pain and lost consciousness. Shortly later she reported headache and vertigo, and numbness of the complete left side of her body. Neurologic examination revealed reduced sensibility to all modalities, a positive Romberg test, and vertigo. Cerebral MRI revealed no pathologic findings. Both children experienced a strikingly similar clinical course. The chronology of events strongly suggests that both patients were suffering from arterial gas embolism. This condition has been reported for the first time to occur in children after breath-hold diving beneath the water surface without glossopharyngeal insufflation. PMID:26260715

  12. An Atypical Case of Taravana Syndrome in a Breath-Hold Underwater Fishing Champion: A Case Report

    PubMed Central

    Foresta, Grazia; Strano, Giustino; Strano, Maria Teresa; Montalto, Francesca; Garbo, Domenico

    2013-01-01

    Dysbaric accidents are usually referred to compressed air-supplied diving. Nonetheless, some cases of decompression illness are known to have occurred among breath-hold (BH) divers also, and they are reported in the medical literature. A male BH diver (57 years old), underwater fishing champion, presented neurological disorders as dizziness, sensory numbness, blurred vision, and left frontoparietal pain after many dives to a 30–35 meters sea water depth with short surface intervals. Symptoms spontaneously regressed and the patient came back home. The following morning, pain and neurological impairment occurred again and the diver went by himself to the hospital where he had a generalized tonic-clonic seizure and lost consciousness. A magnetic resonance imaging of the brain disclofsed a cortical T1-weighted hypointense area in the temporal region corresponding to infarction with partial hemorrhage. An early hyperbaric oxygen therapy led to prompt resolution of neurological findings. All clinical and imaging characteristics were referable to the Taravana diving syndrome, induced by repetitive prolonged deep BH dives. The reappearance of neurological signs after an uncommon 21-hour symptom-free interval may suggest an atypical case of Taravana syndrome. PMID:23970902

  13. An atypical case of taravana syndrome in a breath-hold underwater fishing champion: a case report.

    PubMed

    Cortegiani, Andrea; Foresta, Grazia; Strano, Giustino; Strano, Maria Teresa; Montalto, Francesca; Garbo, Domenico; Raineri, Santi Maurizio

    2013-01-01

    Dysbaric accidents are usually referred to compressed air-supplied diving. Nonetheless, some cases of decompression illness are known to have occurred among breath-hold (BH) divers also, and they are reported in the medical literature. A male BH diver (57 years old), underwater fishing champion, presented neurological disorders as dizziness, sensory numbness, blurred vision, and left frontoparietal pain after many dives to a 30-35 meters sea water depth with short surface intervals. Symptoms spontaneously regressed and the patient came back home. The following morning, pain and neurological impairment occurred again and the diver went by himself to the hospital where he had a generalized tonic-clonic seizure and lost consciousness. A magnetic resonance imaging of the brain disclofsed a cortical T1-weighted hypointense area in the temporal region corresponding to infarction with partial hemorrhage. An early hyperbaric oxygen therapy led to prompt resolution of neurological findings. All clinical and imaging characteristics were referable to the Taravana diving syndrome, induced by repetitive prolonged deep BH dives. The reappearance of neurological signs after an uncommon 21-hour symptom-free interval may suggest an atypical case of Taravana syndrome. PMID:23970902

  14. Changes in partial pressures of respiratory gases during submerged voluntary breath hold across odontocetes: is body mass important?

    PubMed

    Noren, S R; Williams, T M; Ramirez, K; Boehm, J; Glenn, M; Cornell, L

    2012-02-01

    Odontocetes have an exceptional range in body mass spanning 10(3) kg across species. Because, size influences oxygen utilization and carbon dioxide production rates in mammals, this lineage likely displays an extraordinary variation in oxygen store management compared to other marine mammal groups. To examine this, we measured changes in the partial pressures of respiratory gases ([Formula: see text], [Formula: see text]), pH, and lactate in the blood during voluntary, quiescent, submerged breath holds in Pacific white-sided dolphins (Lagenorhynchus obliquidens), bottlenose dolphins (Tursiops truncatus), and a killer whale (Orcinus orca) representing a mass range of 96-3,850 kg. These measurements provided an empirical determination of the effect of body size on the variability in blood biochemistry during breath hold and experimentally determined aerobic dive limits (ADL) within one taxonomic group (odontocetes). For the species in this study, maximum voluntary breath-hold duration was positively correlated with body mass, ranging from 3.5 min in white-sided dolphins to 13.3 min for the killer whale. Variation in breath-hold duration was associated with differences in the rate of change for [Formula: see text] throughout breath hold; [Formula: see text] decreased twice as fast for the two smaller species (-0.6 mmHg O(2) min(-1)) compared to the largest species (-0.3 mmHg O(2) min(-1)). In contrast, the rate of increase in [Formula: see text] during breath hold was similar across species. These results demonstrate that large body size in odontocetes facilitates increased aerobic breath-hold capacity as mediated by decreased mass-specific metabolic rates (rates of change in [Formula: see text] served as a proxy for oxygen utilization). Indeed the experimentally determined 5 min ADL for bottlenose dolphins was surpassed by the 13.3 min maximum breath hold of the killer whale, which did not end in a rise in lactate. Rather, breath hold ended voluntarily as respiratory

  15. Comparison of Liver Tumor Motion With and Without Abdominal Compression Using Cine-Magnetic Resonance Imaging

    SciTech Connect

    Eccles, Cynthia L.; Patel, Ritesh; Simeonov, Anna K.; Lockwood, Gina; Haider, Masoom; Dawson, Laura A.

    2011-02-01

    Purpose: Abdominal compression (AC) can be used to reduce respiratory liver motion in patients undergoing liver stereotactic body radiotherapy. The purpose of the present study was to measure the changes in three-dimensional liver tumor motion with and without compression using cine-magnetic resonance imaging. Patients and Methods: A total of 60 patients treated as a part of an institutional research ethics board-approved liver stereotactic body radiotherapy protocol underwent cine T2-weighted magnetic resonance imaging through the tumor centroid in the coronal and sagittal planes. A total of 240 cine-magnetic resonance imaging sequences acquired at one to three images each second for 30-60 s were evaluated using an in-house-developed template matching tool (based on the coefficient correlation) to measure the magnitude of the tumor motion. The average tumor edge displacements were used to determine the magnitude of changes in the caudal-cranial (CC) and anteroposterior (AP) directions, with and without AC. Results: The mean tumor motion without AC of 11.7 mm (range, 4.8-23.3) in the CC direction was reduced to 9.4 mm (range, 1.6-23.4) with AC. The tumor motion was reduced in both directions (CC and AP) in 52% of the patients and in a single direction (CC or AP) in 90% of the patients. The mean decrease in tumor motion with AC was 2.3 and 0.6 mm in the CC and AP direction, respectively. Increased motion occurred in one or more directions in 28% of patients. Clinically significant (>3 mm) decreases were observed in 40% and increases in <2% of patients in the CC direction. Conclusion: AC can significantly reduce three-dimensional liver tumor motion in most patients, although the magnitude of the reduction was smaller than previously reported.

  16. Quantification of Esophageal Tumor Motion on Cine-Magnetic Resonance Imaging

    SciTech Connect

    Lever, Frederiek M.; Lips, Irene M.; Crijns, Sjoerd P.M.; Reerink, Onne; Lier, Astrid L.H.M.W. van; Moerland, Marinus A.; Vulpen, Marco van; Meijer, Gert J.

    2014-02-01

    Purpose: To quantify the movement of esophageal tumors noninvasively on cine-magnetic resonance imaging (MRI) by use of a semiautomatic method to visualize tumor movement directly throughout multiple breathing cycles. Methods and Materials: Thirty-six patients with esophageal tumors underwent MRI. Tumors were located in the upper (8), middle (7), and lower (21) esophagus. Cine-MR images were collected in the coronal and sagittal plane during 60 seconds at a rate of 2 Hz. An adaptive correlation filter was used to automatically track a previously marked reference point. Tumor movement was measured in the craniocaudal (CC), left–right (LR), and anteroposterior (AP) directions and its relationship along the longitudinal axis of the esophagus was investigated. Results: Tumor registration within the individual images was typically done at a millisecond time scale. The mean (SD) peak-to-peak displacements in the CC, AP, and LR directions were 13.3 (5.2) mm, 4.9 (2.5) mm, and 2.7 (1.2) mm, respectively. The bandwidth to cover 95% of excursions from the mean position (c95) was also calculated to exclude outliers caused by sporadic movements. The mean (SD) c95 values were 10.1 (3.8) mm, 3.7 (1.9) mm, and 2.0 (0.9) mm in the CC, AP, and LR dimensions. The end-exhale phase provided a stable position in the respiratory cycle, compared with more variety in the end-inhale phase. Furthermore, lower tumors showed more movement than did higher tumors in the CC and AP directions. Conclusions: Intrafraction tumor movement was highly variable between patients. Tumor position proved the most stable during the respiratory cycle in the end-exhale phase. A better understanding of tumor motion makes it possible to individualize radiation delivery strategies accordingly. Cine-MRI is a successful noninvasive modality to analyze motion for this purpose in the future.

  17. Real-time automatic fiducial marker tracking in low contrast cine-MV images

    SciTech Connect

    Lin, Wei-Yang; Lin, Shu-Fang; Yang, Sheng-Chang; Liou, Shu-Cheng; Nath, Ravinder; Liu Wu

    2013-01-15

    Purpose: To develop a real-time automatic method for tracking implanted radiographic markers in low-contrast cine-MV patient images used in image-guided radiation therapy (IGRT). Methods: Intrafraction motion tracking using radiotherapy beam-line MV images have gained some attention recently in IGRT because no additional imaging dose is introduced. However, MV images have much lower contrast than kV images, therefore a robust and automatic algorithm for marker detection in MV images is a prerequisite. Previous marker detection methods are all based on template matching or its derivatives. Template matching needs to match object shape that changes significantly for different implantation and projection angle. While these methods require a large number of templates to cover various situations, they are often forced to use a smaller number of templates to reduce the computation load because their methods all require exhaustive search in the region of interest. The authors solve this problem by synergetic use of modern but well-tested computer vision and artificial intelligence techniques; specifically the authors detect implanted markers utilizing discriminant analysis for initialization and use mean-shift feature space analysis for sequential tracking. This novel approach avoids exhaustive search by exploiting the temporal correlation between consecutive frames and makes it possible to perform more sophisticated detection at the beginning to improve the accuracy, followed by ultrafast sequential tracking after the initialization. The method was evaluated and validated using 1149 cine-MV images from two prostate IGRT patients and compared with manual marker detection results from six researchers. The average of the manual detection results is considered as the ground truth for comparisons. Results: The average root-mean-square errors of our real-time automatic tracking method from the ground truth are 1.9 and 2.1 pixels for the two patients (0.26 mm/pixel). The

  18. Breath holding duration as a measure of distress tolerance: examining its relation to measures of executive control.

    PubMed

    Sütterlin, Stefan; Schroijen, Mathias; Constantinou, Elena; Smets, Elyn; Van den Bergh, Omer; Van Diest, Ilse

    2013-01-01

    Recent research considers distress (in)tolerance as an essential component in the development of various forms of psychopathology. A behavioral task frequently used to assess distress tolerance is the breath holding task. Although breath holding time (BHT) has been associated with behavioral outcomes related to inhibitory control (e.g., smoking cessation), the relationship among breath holding and direct measures of executive control has not yet been thoroughly examined. The present study aims to assess (a) the BHT-task's test-retest reliability in a 1-year follow-up and (b) the relationship between a series of executive function tasks and breath holding duration. One hundred and thirteen students completed an initial BHT assessment, 58 of which also completed a series of executive function tasks [the Wisconsin Card Sorting Test (WCST), the Parametric Go/No-Go task and the N-back memory updating task]. A subsample of these students (N = 34) repeated the breath holding task in a second session 1 year later. Test-retest reliability of the BHT-task over a 1-year period was high (r = 0.67, p < 0.001), but none of the executive function tasks was significantly associated with BHT. The rather moderate levels of unpleasantness induced by breath holding in our sample may suggest that other processes (physiological, motivational) besides distress tolerance influence BHT. Overall, the current findings do not support the assumption of active inhibitory control in the BHT-task in a healthy sample. Our findings suggest that individual differences (e.g., in interoceptive or anxiety sensitivity) should be taken into account when examining the validity of BHT as a measure of distress tolerance. PMID:23908639

  19. Laughter is not always funny: breath-holding spells in familial dysautonomia.

    PubMed

    Maayan, Channa; Katz, Eliot; Begin, Michal; Yuvchev, Ivelin; Kharasch, Virginia S

    2015-02-01

    Familial dysautonomia (FD) is a genetic disease characterized by primary autonomic dysfunction including parasympathetic hypersensitivity. Breath-holding spells (BHS) are believed to be caused by autonomic dysregulation mediated via the vagus nerve and increased in patients with a family history of BHS. Details and understanding of its pathophysiology are lacking. In this retrospective study of patients with FD, the incidence of BHS was higher at 53.3%, compared with previous studies in normal children. Laughter as a precipitating factor for BHS has not been previously reported in FD and occurred in 10% of patients in this study. Lower lung volumes, chronic lung disease, chronic CO2 retention, and inadequate autonomic compensation occur in those with FD leading to a higher incidence and severity of BHS when crying or laughing. Thus, FD may be a good model for understanding manifestations of the autonomic nervous system dysfunction and contribute to our knowledge of BHS mechanisms. PMID:25539948

  20. Hemoptysis and pneumomediastinum after breath-hold diving in shallow water: a case report.

    PubMed

    Henckes, A; Arvieux, J; Cochard, G; Jézéquel, P; Arvieux, C C

    2011-01-01

    We report the case of a healthy 21-year-old woman who performed iterative breath-hold dives in relatively cold water, not exceeding depths of 5 meters but with "empty lungs." At the end of a dive, after experiencing an intense involuntary diaphragmatic contraction underwater, she presented hemoptysis followed by chest pain and cough. Chest radiography and computed tomography were performed 24 hours later, confirming the diagnosis of pneumomediastinum. The clinical course was benign: However, chest pain and effort dyspnea lasted for a few weeks. The pathophysiology of this accident may be explained by a combination of mechanisms involved in several clinical entities, namely pulmonary edema of immersion, pulmonary barotrauma and spontaneous pneumomediastinum. PMID:21721355

  1. Mechanics of airway and alveolar collapse in human breath-hold diving.

    PubMed

    Fitz-Clarke, John R

    2007-11-15

    A computational model of the human respiratory tract was developed to study airway and alveolar compression and re-expansion during deep breath-hold dives. The model incorporates the chest wall, supraglottic airway, trachea, branched airway tree, and elastic alveoli assigned time-dependent surfactant properties. Total lung collapse with degassing of all alveoli is predicted to occur around 235 m, much deeper than estimates for aquatic mammals. Hysteresis of the pressure-volume loop increases with maximum diving depth due to progressive alveolar collapse. Reopening of alveoli occurs stochastically as airway pressure overcomes adhesive and compressive forces on ascent. Surface area for gas exchange vanishes at collapse depth, implying that the risk of decompression sickness should reach a plateau beyond this depth. Pulmonary capillary transmural stresses cannot increase after local alveolar collapse. Consolidation of lung parenchyma might provide protection from capillary injury or leakage caused by vascular engorgement due to outward chest wall recoil at extreme depths. PMID:17827075

  2. Segmentation of cardiac magnetic resonance cine images of single ventricle: including or excluding the accessorial ventricle?

    PubMed

    Secchi, Francesco; Resta, Elda Chiara; Di Leo, Giovanni; Petrini, Marcello; Messina, Carmelo; Carminati, Mario; Sardanelli, Francesco

    2014-08-01

    Our aim was to compare two different approaches for segmentation of single ventricle (SV) on cardiac magnetic resonance (CMR) cine images. We retrospectively studied 30 consecutive patients (23 males; aged 27 ± 10 years) with a treated SV who underwent 1.5-T CMR using ECG-triggered axial true-FISP, HASTE and cine true-FISP sequences. We classified patients for visceroatrial situs, cardiac axis orientation, ventricular loop, morphology of SV and position of great arteries. One experienced reader segmented cine images twice, firstly including only the systemic ventricle, secondly including both systemic and accessorial ventricles. Ejection fraction (EF), indexed end-diastolic volume (EDVI), end-systolic volume (ESVI), and stroke volume (SVI) were calculated. Data were presented as medians and interquartile intervals. Four patients presented dextrocardia and one patient mesocardia. Two had situs ambiguus with asplenia and one situs ambiguus with polisplenia. Four patients showed right morphology of the SV and three levo-ventricle loop. We found 14 levo-trasposition of great arteries (TGA), 4 levo-malposition of great arteries (MGA), four dextro-MGA, two dextro-TGA, and one inverted vessel position. When segmenting only the systemic ventricle, EDVI (mL/m2) was 65 (50-91), when segmenting both ventricles 76 (58-110) (P < 0.001); ESVI (mL/m2) was 32 (24-45) and 45 (33-60), respectively (P < 0.001); EF (%) was 49 (43-57) and 33 (24-47), respectively (P = 0.003); SVI (mL/m2) was 34 (17-48) and 33 (24-47) (P = 0.070). The inclusion of the accessorial ventricle in the segmentation of SV produce a biased lower EF showing a very low contribution to the pump function. PMID:24801178

  3. Effect of breath holding on cerebrovascular hemodynamics in normal pregnancy and preeclampsia.

    PubMed

    van Veen, Teelkien R; Panerai, Ronney B; Haeri, Sina; Zeeman, Gerda G; Belfort, Michael A

    2015-04-01

    Preeclampsia (PE) is associated with endothelial dysfunction and impaired autonomic function, which is hypothesized to cause cerebral hemodynamic abnormalities. Our aim was to test this hypothesis by estimating the difference in the cerebrovascular response to breath holding (BH; known to cause sympathetic stimulation) between women with preeclampsia and a group of normotensive controls. In a prospective cohort analysis, cerebral blood flow velocity (CBFV) in the middle cerebral artery (transcranial Doppler), blood pressure (BP, noninvasive arterial volume clamping), and end-tidal carbon dioxide (EtCO2) were simultaneously recorded during a 20-s breath hold maneuver. CBFV changes were broken down into standardized subcomponents describing the relative contributions of BP, cerebrovascular resistance index (CVRi), critical closing pressure (CrCP), and resistance area product (RAP). The area under the curve (AUC) was calculated for changes in relation to baseline values. A total of 25 preeclamptic (before treatment) and 25 normotensive women in the second half of pregnancy were enrolled, and, 21 patients in each group were included in the analysis. The increase in CBFV and EtCO2 was similar in both groups. However, the AUC for CVRi and RAP during BH was significantly different between the groups (3.05 ± 2.97 vs. -0.82 ± 4.98, P = 0.006 and 2.01 ± 4.49 vs. -2.02 ± 7.20, P = 0.037), indicating an early, transient increase in CVRi and RAP in the control group, which was absent in PE. BP had an equal contribution in both groups. Women with preeclampsia have an altered initial CVRi response to the BH maneuver. We propose that this is due to blunted sympathetic or myogenic cerebrovascular response in women with preeclampsia. PMID:25614597

  4. [Research of Left Ventricle Function Analysis Using Real-time Cardiac Magnetic Resonance Imaging].

    PubMed

    Yang, Fan; He, Yan; Zhang, Jie; Wu, Yin

    2015-12-01

    Real-time free breathing cardiac cine imaging is a reproducible method with shorter acquisition time and without breath-hold for cardiac magnetic resonance imaging. However, the detection of end-diastole and end-systole frames of real-time free breathing cardiac cine imaging for left ventricle function analysis is commonly completed by visual identification, which is time-consuming and laborious. In order to save processing time, we propose a method for semi-automatic identification of end-diastole and end-systole frames. The method fits respiratory motion signal and acquires the expiration phase, end-diastole and end-systole frames by cross correlation coefficient. The procedure successfully worked on ten healthy volunteers and validated by the analysis of left ventricle function compared to the standard breath-hold steady-state free precession cardiac cine imaging without any significant statistical differences. The results demonstrated that the present method could correctly detect end-diastole and end-systole frames. In the future, this technique may be used for rapid left ventricle function analysis in clinic. PMID:27079101

  5. 3D tongue motion from tagged and cine MR images.

    PubMed

    Xing, Fangxu; Woo, Jonghye; Murano, Emi Z; Lee, Junghoon; Stone, Maureen; Prince, Jerry L

    2013-01-01

    Understanding the deformation of the tongue during human speech is important for head and neck surgeons and speech and language scientists. Tagged magnetic resonance (MR) imaging can be used to image 2D motion, and data from multiple image planes can be combined via post-processing to yield estimates of 3D motion. However, lacking boundary information, this approach suffers from inaccurate estimates near the tongue surface. This paper describes a method that combines two sources of information to yield improved estimation of 3D tongue motion. The method uses the harmonic phase (HARP) algorithm to extract motion from tags and diffeomorphic demons to provide surface deformation. It then uses an incompressible deformation estimation algorithm to incorporate both sources of displacement information to form an estimate of the 3D whole tongue motion. Experimental results show that use of combined information improves motion estimation near the tongue surface, a problem that has previously been reported as problematic in HARP analysis, while preserving accurate internal motion estimates. Results on both normal and abnormal tongue motions are shown. PMID:24505742

  6. A size-based emphysema severity index: robust to the breath-hold-level variations and correlated with clinical parameters

    PubMed Central

    Hwang, Jeongeun; Lee, Minho; Lee, Sang Min; Oh, Sang Young; Oh, Yeon-Mok; Kim, Namkug; Seo, Joon Beom

    2016-01-01

    Objective To determine the power-law exponents (D) of emphysema hole-size distributions as a competent emphysema index. Robustness to extreme breath-hold-level variations and correlations with clinical parameters for chronic obstructive pulmonary disease (COPD) were investigated and compared to a conventional emphysema index (EI%). Patients and methods A total of 100 patients with COPD (97 males and three females of mean age 67±7.9 years) underwent multidetector row computed tomography scanning at full inspiration and full expiration. The diameters of the emphysematous holes were estimated and quantified with a fully automated algorithm. Power-law exponents (D) of emphysematous hole-size distribution were evaluated. Results The diameters followed a power-law distribution in all cases, suggesting the scale-free nature of emphysema. D of inspiratory and expiratory computed tomography of patients showed intraclass correlation coefficients >0.8, indicating statistically absolute agreement of different breath-hold levels. By contrast, the EI% failed to agree. Bland–Altman analysis also revealed the superior robustness of D to EI%. D also significantly correlated with clinical parameters such as airflow limitation, diffusion capacity, exercise capacity, and quality of life. Conclusion The D of emphysematous hole-size distribution is robust to breath-hold-level variations and sensitive to the severity of emphysema. This measurement may help rule out the confounding effects of variations in breath-hold levels. PMID:27536095

  7. [Value of cine magnetic resonance imaging in the diagnosis and quantification of valvular regurgitation. Comparison with angiography and Doppler echocardiography].

    PubMed

    Germain, P; Baruthio, J; Roul, G; Mossard, J M; Bareiss, P; Wecker, D; Chambron, J; Sacrez, A

    1989-10-01

    Thirty-three patients presenting with regurgitation of the mitral valve (19 cases), tricuspid valve (14 cases) or aortic valve (11 cases) documented by angiography (n = 20) and/or doppler-echocardiography (n = 28) were examined by cine-MRI in order to test this method in valvular regurgitation. Sixteen ECG-synchronized cine-MRI images were acquired by the GRASS technique every 40 ms on appropriate projections, with a resistive 0.28 Tesla Bruker magnet. The semiology of normal and pathological blood flow images at cine-MRI is described. Valvular regurgitations present as "signal void" jets the chronology and spatial extension of which depend on the severity of the lesion. The differential diagnosis with physiological flows is discussed. The diagnostic sensitivity of the method was 29/29 when compared with angiography and 29/33 when compared with doppler-echocardiography (2 cases of 1/4 mitral regurgitation and 2 cases 1/4 tricuspid regurgitation were not visible at cine-MRI). The specificity of this method, as can be judged from 104 patients explored, also seems to be satisfactory. The severity of regurgitation was graded from 1 to 4 with the three methods, on the basis of strict criteria. The differences in grade evaluation exceeded +/- 1 point in only one case of mitral regurgitation which was greatly underestimated by the doppler method as compared with angiography and cine-MRI. Thus, cine-MRI is a reliable method to evaluate valvular regurgitations and their severity. It solves the practical problem raised by non-echogenic patients when catheterization is to be postponed or avoided. PMID:2512868

  8. Effects of Incentive Spirometry on Respiratory Motion in Healthy Subjects Using Cine Breathing Magnetic Resonance Imaging

    PubMed Central

    Akazawa, Tsutomu; Sakuma, Tsuyoshi; Nagaya, Shigeyuki; Sonoda, Masaru; Tanaka, Yuji; Katogi, Takehide; Nemoto, Tetsuharu; Minami, Shohei

    2015-01-01

    Objective To investigate the effectiveness of incentive spirometry on respiratory motion in healthy subjects using cine breathing magnetic resonance imaging (MRI). Methods Ten non-smoking healthy subjects without any history of respiratory disease were studied. Subjects were asked to perform pulmonary training using incentive spirometry every day for two weeks. To assess the effectiveness of this training, pulmonary function tests and cine breathing MRI were performed before starting pulmonary training and two weeks after its completion. Results After training, there were significant improvements in vital capacity (VC) from 3.58±0.8 L to 3.74±0.8 L and in %VC from 107.4±10.8 to 112.1±8.2. Significant changes were observed in the right diaphragm motion, right chest wall motion, and left chest wall motion, which were increased from 55.7±9.6 mm to 63.4±10.2 mm, from 15.6±6.1 mm to 23.4±10.4 mm, and from 16.3±7.6 mm to 22.0±9.8 mm, respectively. Conclusion Two weeks of training using incentive spirometry provided improvements in pulmonary function and respiratory motion, which suggested that incentive spirometry may be a useful preoperative modality for improving pulmonary function during the perioperative period. PMID:26161341

  9. The effect of climbing Mount Everest on spleen contraction and increase in hemoglobin concentration during breath holding and exercise.

    PubMed

    Engan, Harald K; Lodin-Sundström, Angelica; Schagatay, Fanny; Schagatay, Erika

    2014-04-01

    Release of stored red blood cells resulting from spleen contraction improves human performance in various hypoxic situations. This study determined spleen volume resulting from two contraction-evoking stimuli: breath holding and exercise before and after altitude acclimatization during a Mount Everest ascent (8848 m). Eight climbers performed the following protocol before and after the climb: 5 min ambient air respiration at 1370 m during rest, 20 min oxygen respiration, 20 min ambient air respiration at 1370 m, three maximal-effort breath holds spaced by 2 min, 10 min ambient air respiration, 5 min of cycling at 100 W, and finally 10 min ambient air respiration. We measured spleen volume by ultrasound and capillary hemoglobin (HB) concentration after each exposure, and heart rate (HR) and arterial oxygen saturation (Sao2) continuously. Mean (SD) baseline spleen volume was unchanged at 213 (101) mL before and 206 (52) mL after the climb. Before the climb, spleen volume was reduced to 184 (83) mL after three breath holds, and after the climb three breath holds resulted in a spleen volume of 132 (26) mL (p=0.032). After exercise, the preclimb spleen volume was 186 (89) mL vs. 112 (389) mL) after the climb (p=0.003). Breath hold duration and cardiovascular responses were unchanged after the climb. We concluded that spleen contraction may be enhanced by altitude acclimatization, probably reflecting both the acclimatization to chronic hypoxic exposure and acute hypoxia during physical work. PMID:24673535

  10. SU-E-J-33: Cardiac Movement in Deep Inspiration Breath-Hold for Left-Breast Cancer Radiotherapy

    SciTech Connect

    Kim, M; Lee, S; Suh, T

    2014-06-01

    Purpose: The present study was designed to investigate the displacement of heart using Deep Inspiration Breath Hold (DIBH) CT data compared to free-breathing (FB) CT data and radiation exposure to heart. Methods: Treatment planning was performed on the computed tomography (CT) datasets of 20 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ≥ 95% of the prescribed dose and that the volume inside the CTV receiving > 107% of the prescribed dose should be minimized. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated. Results: The maximum and minimum left-right (LR) displacements of heart were 8.9 mm and 3 mm, respectively. The heart moved > 4 mm in the LR direction in 17 of the 20 patients. The distances between the heart and left breast ranged from 8.02–17.68 mm (mean, 12.23 mm) and 7.85–12.98 mm (mean, 8.97 mm) with DIBH CT and FB CT, respectively. The maximum doses to the heart were 3115 cGy and 4652 cGy for the DIBH and FB CT dataset, respectively. Conclusion: The present study has demonstrated that the DIBH technique could help to reduce the risk of radiation dose-induced cardiac toxicity by using movement of cardiac; away from radiation field. The DIBH technique could be used in an actual treatment room for a few minutes and could effectively reduce the cardiac dose when used with a sub-device or image acquisition standard to maintain consistent respiratory motion.

  11. Positional Reproducibility of Pancreatic Tumors Under End-Exhalation Breath-Hold Conditions Using a Visual Feedback Technique

    SciTech Connect

    Nakamura, Mitsuhiro; Shibuya, Keiko; Shiinoki, Takehiro; Matsuo, Yukinori; Nakamura, Akira; Nakata, Manabu; Sawada, Akira; Mizowaki, Takashi; Hiraoka, Masahiro

    2011-04-01

    Purpose: To assess positional reproducibility of pancreatic tumors under end-exhalation (EE) breath-hold (BH) conditions with a visual feedback technique based on computed tomography (CT) images. Methods and Materials: Ten patients with pancreatic cancer were enrolled in an institutional review board-approved trial. All patients were placed in a supine position on an individualized vacuum pillow with both arms raised. At the time of CT scan, they held their breath at EE with the aid of video goggles displaying their abdominal displacement. Each three-consecutive helical CT data set was acquired four times (sessions 1-4; session 1 corresponded to the time of CT simulation). The point of interest within or in proximity to a gross tumor volume was defined based on certain structural features. The positional variations in point of interest and margin size required to cover positional variations were assessed. Results: The means {+-} standard deviations (SDs) of intrafraction positional variations were 0.0 {+-} 1.1, 0.1 {+-} 1.2, and 0.1 {+-} 1.0 mm in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions, respectively (p = 0.726). The means {+-} SDs of interfraction positional variations were 0.3 {+-} 2.0, 0.8 {+-} 1.8, and 0.3 {+-} 1.8 mm in the LR, AP, and SI directions, respectively (p = 0.533). Population-based margin sizes required to cover 95th percentiles of the overall positional variations were 4.7, 5.3, and 4.9 mm in the LR, AP, and SI directions, respectively. Conclusions: A margin size of 5 mm was needed to cover the 95th percentiles of the overall positional variations under EE-BH conditions, using this noninvasive approach to motion management for pancreatic tumors.

  12. Three-dimensional MR Cholangiopancreatography in a Breath Hold with Sparsity-based Reconstruction of Highly Undersampled Data.

    PubMed

    Chandarana, Hersh; Doshi, Ankur M; Shanbhogue, Alampady; Babb, James S; Bruno, Mary T; Zhao, Tiejun; Raithel, Esther; Zenge, Michael O; Li, Guobin; Otazo, Ricardo

    2016-08-01

    Purpose To develop a three-dimensional breath-hold (BH) magnetic resonance (MR) cholangiopancreatographic protocol with sampling perfection with application-optimized contrast using different flip-angle evolutions (SPACE) acquisition and sparsity-based iterative reconstruction (SPARSE) of prospectively sampled 5% k-space data and to compare the results with conventional respiratory-triggered (RT) acquisition. Materials and Methods This HIPAA-compliant prospective study was institutional review board approved. Twenty-nine patients underwent conventional RT SPACE and BH-accelerated SPACE acquisition with 5% k-space sampling at 3 T. Spatial resolution and other parameters were matched when possible. BH SPACE images were reconstructed by enforcing joint multicoil sparsity in the wavelet domain (SPARSE-SPACE). Two board-certified radiologists independently evaluated BH SPARSE-SPACE and RT SPACE images for image quality parameters in the pancreatic duct and common bile duct by using a five-point scale. The Wilcoxon signed-rank test was used to compare BH SPARSE-SPACE and RT SPACE images. Results Acquisition time for BH SPARSE-SPACE was 20 seconds, which was significantly (P < .001) shorter than that for RT SPACE (mean ± standard deviation, 338.8 sec ± 69.1). Overall image quality scores were higher for BH SPARSE-SPACE than for RT SPACE images for both readers for the proximal, middle, and distal pancreatic duct, but the difference was not statistically significant (P > .05). For reader 1, distal common bile duct scores were significantly higher with BH SPARSE-SPACE acquisition (P = .036). More patients had acceptable or better overall image quality (scores ≥ 3) with BH SPARSE-SPACE than with RT SPACE acquisition, respectively, for the proximal (23 of 29 [79%] vs 22 of 29 [76%]), middle (22 of 29 [76%] vs 18 of 29 [62%]), and distal (20 of 29 [69%] vs 13 of 29 [45%]) pancreatic duct and the proximal (25 of 28 [89%] vs 22 of 28 [79%]) and distal (25 of 28 [89%] vs 24

  13. The impact of cine EPID image acquisition frame rate on markerless soft-tissue tracking

    SciTech Connect

    Yip, Stephen Rottmann, Joerg; Berbeco, Ross

    2014-06-15

    Purpose: Although reduction of the cine electronic portal imaging device (EPID) acquisition frame rate through multiple frame averaging may reduce hardware memory burden and decrease image noise, it can hinder the continuity of soft-tissue motion leading to poor autotracking results. The impact of motion blurring and image noise on the tracking performance was investigated. Methods: Phantom and patient images were acquired at a frame rate of 12.87 Hz with an amorphous silicon portal imager (AS1000, Varian Medical Systems, Palo Alto, CA). The maximum frame rate of 12.87 Hz is imposed by the EPID. Low frame rate images were obtained by continuous frame averaging. A previously validated tracking algorithm was employed for autotracking. The difference between the programmed and autotracked positions of a Las Vegas phantom moving in the superior-inferior direction defined the tracking error (δ). Motion blurring was assessed by measuring the area change of the circle with the greatest depth. Additionally, lung tumors on 1747 frames acquired at 11 field angles from four radiotherapy patients are manually and automatically tracked with varying frame averaging. δ was defined by the position difference of the two tracking methods. Image noise was defined as the standard deviation of the background intensity. Motion blurring and image noise are correlated with δ using Pearson correlation coefficient (R). Results: For both phantom and patient studies, the autotracking errors increased at frame rates lower than 4.29 Hz. Above 4.29 Hz, changes in errors were negligible withδ < 1.60 mm. Motion blurring and image noise were observed to increase and decrease with frame averaging, respectively. Motion blurring and tracking errors were significantly correlated for the phantom (R = 0.94) and patient studies (R = 0.72). Moderate to poor correlation was found between image noise and tracking error with R −0.58 and −0.19 for both studies, respectively. Conclusions: Cine EPID

  14. SU-E-T-326: The Oxygen Saturation (SO2) and Breath-Holding Time Variation Applied Active Breathing Control (ABC)

    SciTech Connect

    Gong, G; Yin, Y

    2014-06-01

    Purpose: To study the oxygen saturation (SO2) and breath-holding time variation applied active breathing control (ABC) in radiotherapy of tumor. Methods: 24 volunteers were involved in our trials, and they all did breath-holding motion assisted by ELEKTA Active Breathing Coordinator 2.0 for 10 times respectively. And the patient monitor was used to observe the oxygen saturation (SO2) variation. The variation of SO2, and length of breath-holding time and the time for recovering to the initial value of SO2 were recorded and analyzed. Results: (1) The volunteers were divided into two groups according to the SO2 variation in breath-holding: A group, 14 cases whose SO2 reduction were more than 2% (initial value was 97% to 99%, while termination value was 91% to 96%); B group, 10 cases were less than 2% in breath-holding without inhaling oxygen. (2) The interfraction breath holding time varied from 8 to 20s for A group compared to the first breath-holding time, and for B group varied from 4 to 14s. (3) The breathing holding time of B group prolonged mean 8s, compared to A group. (4) The time for restoring to the initial value of SO2 was from 10s to 30s. And the breath-holding time shortened obviously for patients whose SO2 did not recover to normal. Conclusion: It is very obvious that the SO2 reduction in breath-holding associated with ABC for partial people. It is necessary to check the SO2 variation in breath training, and enough time should be given to recover SO2.

  15. Ultrasound lung comets induced by repeated breath-hold diving, a study in underwater fishermen.

    PubMed

    Boussuges, A; Coulange, M; Bessereau, J; Gargne, O; Ayme, K; Gavarry, O; Fontanari, P; Joulia, F

    2011-12-01

    Pulmonary edema has been reported in breath-hold divers during fish-catching diving activity. The present study was designed to detect possible increases in extravascular lung water (EVLW) in underwater fishermen after a competition. Thirty healthy subjects were studied. They participated in two different 5-h fish-catching diving competitions: one organized in the winter (10 subjects) and one organized in the autumn (20 subjects). A questionnaire was used to record underwater activity and note respiratory problems. An increase in EVLW was investigated from the detection of ultrasound lung comets (ULC) by chest ultrasonography. Complementary investigations included echocardiography and pulmonary function testing. An increase in EVLW was detected in three out of 30 underwater fishermen after the competition. No signs of cardiovascular dysfunction were found in the entire population and in divers with an increase in the ULC score. Two divers with raised ULC presented respiratory disorders such as cough or shortness of breath. Impairment in spirometric parameters was recorded in these subjects. An increase in EVLW could be observed after a fish-catching diving competition in three out of 30 underwater fishermen. In two subjects, it was related to respiratory disorders and impairment in pulmonary flow. PMID:21535186

  16. Effects of dietary inorganic nitrate on static and dynamic breath-holding in humans.

    PubMed

    Schiffer, Tomas A; Larsen, Filip J; Lundberg, Jon O; Weitzberg, Eddie; Lindholm, Peter

    2013-01-15

    Inorganic nitrate has been shown to reduce oxygen cost during exercise. Since the nitrate-nitrite-NO pathway is facilitated during hypoxia, we investigated the effects of dietary nitrate on oxygen consumption and cardiovascular responses during apnea. These variables were measured in two randomized, double-blind, placebo-controlled, crossover protocols at rest and ergometer exercise in competitive breath-hold divers. Subjects held their breath for predetermined times along with maximum effort apneas after two separate 3-day periods with supplementation of potassium nitrate/placebo. In contrast to our hypothesis, nitrate supplementation led to lower arterial oxygen saturation (SaO(2), 77 ± 3%) compared to placebo (80 ± 2%) during static apnea, along with lower end-tidal fraction of oxygen (FETO(2)) after 4 min of apnea (nitrate 6.9 ± 0.4% vs. placebo 7.6 ± 0.4%). Maximum apnea duration was shorter after nitrate (329 ± 13 s) compared to placebo (344 ± 13 s). During cycle ergometry nitrate had no effect on SaO(2), FETO(2) or maximum apnea duration. The negative effects of inorganic nitrate during static apnea may be explained by an attenuated diving response. PMID:23099220

  17. Electrocardiographic aspects of deep dives in elite breath-hold divers.

    PubMed

    Lemaître, F; Lafay, V; Taylor, M; Costalat, G; Gardette, B

    2013-01-01

    The cardiac diving response, 12-lead electrocardiogram (ECG) and the prevalence, time of onset, and possible associations of cardiac arrhythmias were examined during deep breath-hold (BH) dives. Nine elite BH divers (33.2 +/- 3.6 years; mean +/- SD) performed one constant-weight dive of at least 75% of their best personal performance (70 +/- 7 meters for 141 +/- 22 seconds) wearing a 12-lead ECG Holter monitor. Diving parameters (depth and time), oxygen saturation (SaO2), blood lactate concentration and ventilatory parameters were also recorded. Bradycardia during these dives was pronounced (52.2 +/- 12.2%), with heart rates dropping to 46 +/- 10 beats/minute. The diving reflex was strong, overriding the stimulus of muscular exercise during the ascent phase of the dive for all divers. Classical arrhythmias occurred, mainly after surfacing, and some conduction alterations were detected at the bottom of the dives. The BH divers did not show any right shift of the QRS electrical axis during their dives. PMID:23682546

  18. Modified ventilatory response characteristics to exercise in breath-hold divers.

    PubMed

    Roecker, Kai; Metzger, Jule; Scholz, Tobias; Tetzlaff, Kay; Sorichter, Stephan; Walterspacher, Stephan

    2014-09-01

    Specific adjustments to repeated extreme apnea are not fully known and understood. While a blunted ventilatory chemosensitivity to CO2 is described for elite breath-hold divers (BHDs) at rest, it is unclear whether specific adaptations affect their response to dynamic exercise. Eight elite BHDs with a previously validated decrease in CO2 chemosensitivity, 8 scuba divers (SCDs), and 8 matched control subjects were included in a study where markers of ventilatory response, Fowler's dead space, partial pressure of carbon dioxide (pCO2), and blood lactate concentrations during cycle exercise were measured. Maximal power output did not differ between the groups, but lactate threshold (θL) appeared at a significantly lowered respiratory compensation point (RCP) and at a higher VO2 for the BHDs. End-tidal (petCO2) and estimated arterial pCO2 (paCO2) were significantly higher in BHDs at θL, the RCP, and maximum exhaustion. BHDs showed a significantly (P < .01) slower breathing pattern in relation to a given tidal volume at a specific work rate. In summary, BHDs presented signs of a metabolic shift from aerobic to anaerobic energy supply, decreased chemosensitivity during exercise, and a distinct ventilatory-response pattern during cycle exercise that differs from SCDs and controls. PMID:24231513

  19. Computerized method for measurement of displacement vectors of target positions on EPID cine images in stereotactic radiotherapy

    NASA Astrophysics Data System (ADS)

    Arimura, Hidetaka; Anai, Shigeo; Yoshidome, Satoshi; Nakamura, Katsumasa; Shioyama, Yoshiyuki; Nomoto, Satoshi; Honda, Hiroshi; Onizuka, Yoshihiko; Terashima, Hiromi

    2007-03-01

    The purpose of this study was to develop a computerized method for measurement of displacement vectors of target position on electronic portal imaging device (EPID) cine images in a treatment without implanted markers. Our proposed method was based on a template matching technique with cross-correlation coefficient between a reference portal (RP) image and each consecutive portal (CP) image acquired by the EPID. EPID images with 512×384 pixels (pixel size:0.56 mm) were acquired in a cine mode at a sampling rate of 0.5 frame/sec by using an energy of 4, 6, or 10MV on linear accelerators. The displacement vector of the target on each cine image was determined from the position in which took the maximum cross-correlation value between the RP image and each CP image. We applied our method to EPID cine images of a lung phantom with a tumor model simulating respiratory motion, and 5 cases with a non-small cell lung cancer and one case of metastasis. For validation of our proposed method, displacement vectors of a target position calculated by our method were compared with those determined manually by two radiation oncologists. As a result, for lung phantom images, target displacements by our method correlated well with those by the oncologists (r=0.972 - 0.994). Correlation values for 4 cases ranged from 0.854 to 0.991, but the values for the other two cases were 0.609 and 0.644. This preliminary result suggested that our method may be useful for monitoring of displacement vectors of target positions without implanted markers in stereotactic radiotherapy.

  20. Detection and correction for EPID and gantry sag during arc delivery using cine EPID imaging

    SciTech Connect

    Rowshanfarzad, Pejman; Sabet, Mahsheed; O'Connor, Daryl J.; McCowan, Peter M.; McCurdy, Boyd M. C.; Greer, Peter B.

    2012-02-15

    Purpose: Electronic portal imaging devices (EPIDs) have been studied and used for pretreatment and in-vivo dosimetry applications for many years. The application of EPIDs for dosimetry in arc treatments requires accurate characterization of the mechanical sag of the EPID and gantry during rotation. Several studies have investigated the effects of gravity on the sag of these systems but each have limitations. In this study, an easy experiment setup and accurate algorithm have been introduced to characterize and correct for the effect of EPID and gantry sag during arc delivery. Methods: Three metallic ball bearings were used as markers in the beam: two of them fixed to the gantry head and the third positioned at the isocenter. EPID images were acquired during a 360 deg. gantry rotation in cine imaging mode. The markers were tracked in EPID images and a robust in-house developed MATLAB code was used to analyse the images and find the EPID sag in three directions as well as the EPID + gantry sag by comparison to the reference gantry zero image. The algorithm results were then tested against independent methods. The method was applied to compare the effect in clockwise and counter clockwise gantry rotations and different source-to-detector distances (SDDs). The results were monitored for one linear accelerator over a course of 15 months and six other linear-accelerators from two treatment centers were also investigated using this method. The generalized shift patterns were derived from the data and used in an image registration algorithm to correct for the effect of the mechanical sag in the system. The Gamma evaluation (3%, 3 mm) technique was used to investigate the improvement in alignment of cine EPID images of a fixed field, by comparing both individual images and the sum of images in a series with the reference gantry zero image. Results: The mechanical sag during gantry rotation was dependent on the gantry angle and was larger in the in-plane direction, although

  1. Segmentation of cardiac cine-MR images and myocardial deformation assessment using level set methods.

    PubMed

    Chenoune, Y; Deléchelle, E; Petit, E; Goissen, T; Garot, J; Rahmouni, A

    2005-12-01

    In this paper, we present an original method to assess the deformations of the left ventricular myocardium on cardiac cine-MRI. First, a segmentation process, based on a level set method is directly applied on a 2D + t dataset to detect endocardial contours. Second, the successive segmented contours are matched using a procedure of global alignment, followed by a morphing process based on a level set approach. Finally, local measurements of myocardial deformations are derived from the previously determined matched contours. The validation step is realized by comparing our results to the measurements achieved on the same patients by an expert using the semi-automated HARP reference method on tagged MR images. PMID:16290086

  2. A Method to Create Regional Mechanical Dyssynchrony Maps from Short-Axis Cine SSFP Images

    PubMed Central

    Suever, Jonathan D.; Fornwalt, Brandon K.; Neuman, Lee R.; Delfino, Jana G.; Lloyd, Michael S.; Oshinski, John N.

    2013-01-01

    Purpose To develop a robust method to assess regional mechanical dyssynchrony from cine short-axis MR images. Cardiac resynchronization therapy (CRT) is an effective treatment for patients with heart failure and evidence of left-ventricular (LV) dyssynchrony. Patient response to CRT is greatest when the LV pacing lead is placed in the most dyssynchronous segment. Existing techniques for assessing regional dyssynchrony require difficult acquisition and/or postprocessing. Our goal was to develop a widely applicable and robust method to assess regional mechanical dyssynchrony. Materials and Methods Using the endocardial boundary, radial displacement curves (RDCs) were generated throughout the LV. Cross-correlation was used to determine the delay time between each RDC and a patient-specific reference. Delay times were projected onto the AHA 17-segment model creating a regional dyssynchrony map. Our method was tested in 10 normal individuals and 10 patients enrolled for CRT (QRS>120ms, NYHA III-IV, EF<35%). Results Delay times over the LV were 23.9±33.8ms and 93.1±99.9ms (p<0.001) in normal subjects and patients, respectively. Inter-observer reproducibility for segment averages was 6.8±39.3ms and there was 70% agreement in identifying the latest contracting segment. Conclusion We have developed a method that can reliably calculate regional delay times from cine SSFP images. Maps of regional dyssynchrony could be used to identify the latest-contracting segment to assist in CRT lead implantation. PMID:24123528

  3. 3D cine magnetic resonance imaging of rat lung ARDS using gradient-modulated SWIFT with retrospective respiratory gating

    NASA Astrophysics Data System (ADS)

    Kobayashi, Naoharu; Lei, Jianxun; Utecht, Lynn; Garwood, Michael; Ingbar, David H.; Bhargava, Maneesh

    2015-03-01

    SWeep Imaging with Fourier Transformation (SWIFT) with gradient modulation and DC navigator retrospective gating is introduced as a 3D cine magnetic resonance imaging (MRI) method for the lung. In anesthetized normal rats, the quasi-simultaneous excitation and acquisition in SWIFT enabled extremely high sensitivity to the fast-decaying parenchymal signals (TE=~4 μs), which are invisible with conventional MRI techniques. Respiratory motion information was extracted from DC navigator signals and the SWIFT data were reconstructed to 3D cine images with 16 respiratory phases. To test this technique's capabilities, rats exposed to > 95% O2 for 60 hours for induction of acute respiratory distress syndrome (ARDS), were imaged and compared with normal rat lungs (N=7 and 5 for ARDS and normal groups, respectively). SWIFT images showed lung tissue density differences along the gravity direction. In the cine SWIFT images, a parenchymal signal drop at the inhalation phase was consistently observed for both normal and ARDS rats due to lung inflation (i.e. decrease of the proton density), but the drop was less for ARDS rats. Depending on the respiratory phase and lung region, the lungs from the ARDS rats showed 1-24% higher parenchymal signal intensities relative to the normal rat lungs, likely due to accumulated extravascular water (EVLW). Those results demonstrate that SWIFT has high enough sensitivity for detecting the lung proton density changes due to gravity, different phases of respiration and accumulation of EVLW in the rat ARDS lungs.

  4. Automatic image-driven segmentation of cardiac ventricles in cine anatomical MRI

    NASA Astrophysics Data System (ADS)

    Cocosco, Chris A.; Niessen, Wiro J.; Netsch, Thomas; Vonken, Evert-jan P. A.; Viergever, Max A.

    2005-08-01

    The automatic segmentation of the heart's two ventricles from dynamic ("cine") cardiac anatomical images, such as 3D+time short-axis MRI, is of significant clinical importance. Previously published automated methods have various disadvantages for routine clinical use. This work reports about a novel automatic segmentation method that is very fast, and robust against anatomical variability and image contrast variations. The method is mostly image-driven: it fully exploits the information provided by modern 4D (3D+time) balanced Fast Field Echo (bFFE) cardiac anatomical MRI, and makes only few and plausible assumptions about the images and the imaged heart. Specifically, the method does not need any geometrical shape models nor complex gray-level appearance models. The method simply uses the two ventricles' contraction-expansion cycle, as well as the ventricles' spatial coherence along the time dimension. The performance of the cardiac ventricles segmentation method was demonstrated through a qualitative visual validation on 32 clinical exams: no gross failures for the left-ventricle (right-ventricle) on 32 (30) of the exams were found. Also, a clinical validation of resulting quantitative cardiac functional parameters was performed against a manual quantification of 18 exams; the automatically computed Ejection Fraction (EF) correlated well to the manually computed one: linear regression with RMS=3.7% (RMS expressed in EF units).

  5. Development and application of a real-time monitoring and feedback system for deep inspiration breath hold based on external marker tracking

    SciTech Connect

    Stock, Markus; Kontrisova, Kristina; Dieckmann, Karin; Bogner, Joachim; Poetter, Richard; Georg, Dietmar

    2006-08-15

    Respiration can cause tumor movements in thoracic regions of up to 3 cm. To minimize motion effects several approaches, such as gating and deep inspiration breath hold (DIBH), are still under development. The goal of our study was to develop and evaluate a noninvasive system for gated DIBH (GDIBH) based on external markers. DIBH monitoring was based on an infrared tracking system and an in-house-developed software. The in-house software provided the breathing curve in real time and was used as on-line information for a prototype of a feedback device. Reproducibility and stability of the breath holds were evaluated without and with feedback. Thirty-five patients undergoing stereotactic body radiotherapy (SBRT) performed DIBH maneuvers after each treatment. For 16 patients dynamic imaging sequences on a multislice CT were used to determine the correlation between tumor and external markers. The relative reproducibility of DIBH maneuvers was improved with the feedback device (74.5%{+-}17.1% without versus 93.0%{+-}4.4% with feedback). The correlation between tumor and marker was good (Pearson correlation coefficient 0.83{+-}0.17). The regression slopes showed great intersubject variability but on average the internal margin in a DIBH treatment situation could be theoretically reduced by 3 mm with the feedback device. DIBH monitoring could be realized in a noninvasive manner through external marker tracking. We conclude that reduction of internal margins can be achieved with a feedback system but should be performed with great care due to the individual behavior of target motion.

  6. Release of erythropoietin and neuron-specific enolase after breath holding in competing free divers.

    PubMed

    Kjeld, T; Jattu, T; Nielsen, H B; Goetze, J P; Secher, N H; Olsen, N V

    2015-06-01

    Free diving is associated with extreme hypoxia. This study evaluated the combined effect of maximal static breath holding and underwater swimming on plasma biomarkers of tissue hypoxemia: erythropoietin, neuron-specific enolase and S100B, C-reactive protein, pro-atrial natriuretic peptide, and troponin T. Venous blood samples were obtained from 17 competing free divers before and 3 h after sessions of static apnea and underwater swimming. The heart was evaluated by echocardiography. Static apnea for 293 ± 78 s (mean ± SD) and subsequent 88 ± 21 m underwater swimming increased plasma erythropoietin from 10.6 ± 3.4 to 12.4 ± 4.1 mIU/L (P = 0.013) and neuron-specific enolase from 14.5 ± 5.3 to 24.6 ± 6.4 ng/mL (P = 0.017); C-reactive protein decreased from 0.84 ± 1.0 to 0.71 ± 0.67 mmol/L (P = 0.013). In contrast, plasma concentrations of S100B (P = 0.394), pro-atrial natriuretic peptide (P = 0.549), and troponin T (P = 0.125) remained unchanged and, as assessed by echocardiography, the heart was not affected. In competitive free divers, bouts of static and dynamic apnea increase plasma erythropoietin and neuron-specific enolase, suggesting that renal and neural tissue, rather than the heart, is affected by the hypoxia developed during apnea and underwater swimming. PMID:25142912

  7. Novel Findings in Breath-Holding Spells: A Cross-Sectional Study.

    PubMed

    Azab, Seham F A; Siam, Ahmed G; Saleh, Safaa H; Elshafei, Mona M; Elsaeed, Wafaa F; Arafa, Mohamed A; Bendary, Eman A; Farag, Elsayed M; Basset, Maha A A; Ismail, Sanaa M; Elazouni, Osama M A

    2015-07-01

    The mechanism of breath-holding spells (BHS) is not fully understood and most probably multifactorial; so, this study was designed to clarify the pathophysiology of BHS through assessing some laboratory parameters and electrocardiographic (ECG) changes which might be contributing to the occurrence of the attacks. Another aim of the study was to evaluate the differences in the pathophysiology between pallid and cyanotic types of BHS. This was a prospective study performed in Zagazig University Hospitals. Seventy-six children diagnosed with BHS were included as follows: 32 children with cyanotic BHS, 14 children with pallid BHS, and 30 healthy children as a control group. All children were subjected to the following: full history taking, clinical examination, and laboratory work up in the form of CBC, serum iron, ferritin, and zinc levels. Twenty-four hours ambulatory ECG (Holter) recording was also performed. No significant statistical difference was found between cyanotic and pallid groups regarding family history of BHS, severity, and precipitating factors of the attacks. Frequent runs of respiratory sinus arrhythmia (RSA) during 24  hours ECG were significantly higher in children with BHS; the frequency of RSA was significantly correlated with the frequency (severity) of the attacks. Low serum ferritin was significantly associated with BHS groups but not correlated with the severity of the attacks. Autonomic dysregulation evidenced by frequent RSA is considered to be an important cause of BHS in children and is correlated with the frequency of the attacks. Low serum ferritin is additional factor in the pathophysiology. Both pallid and cyanotic BHS are suggested to be types of the same disease sharing the same pathophysiology. PMID:26181556

  8. Evaluation of intra- and inter-fraction motion in breast radiotherapy using electronic portal cine imaging.

    PubMed

    Kron, T; Lee, C; Perera, F; Yu, E

    2004-10-01

    Breast irradiation is one of the most challenging problems in radiotherapy due to the complex shape of the target volume, proximity of radiation sensitive normal structures and breathing motion. It was the aim of the present study to use electronic portal imaging (EPI) during treatment to determine intra- and inter-fraction motion in patients undergoing radiotherapy and to correlate the magnitude of motion with patient specific parameters. EPI cine images were acquired from the medial tangential fields of twenty radiotherapy patients on a minimum of 5 days each over the course of their treatment. The treatments were administered using 10 MV X-rays and dynamic wedges on a Varian Clinac 2100CD linear accelerator. Depending on the incident dose and the angle of the wedge, between 4 and 16 images could be acquired in one session using an EPI device based on liquid ionization chambers (Varian). The border between lung and chest-wall could be easily detected in all images and quantitative measurements were taken for the amount of lung in the field and the distance of the breast tissue from the field edges. Inter-fraction variability was found to be about twice as large as intra-fraction variability. The largest variability was detected in cranio/caudal direction (intra-fraction: 1.3 +/- 0.4 mm; inter-fraction: 2.6 +/- 1.3 mm) while the lung involvement varied by 1.1 +/- 0.2 mm and 1.8 +/- 0.6 mm intra- and inter-fraction, respectively. This indicates that the effect of breathing motion on the amount of radiated lung was not of major concern in the patients studied. Of other patient specific parameters such as body weight, breast separation, field size and location of the target, only increasing age was significantly correlated with larger inter-fraction motion. Acquisition of EPI cine loops proved to be a quick and easy technique to establish the amount of patient movement during breast radiotherapy. The relatively small variability found in the present pilot study

  9. An initial study on the estimation of time-varying volumetric treatment images and 3D tumor localization from single MV cine EPID images

    SciTech Connect

    Mishra, Pankaj Mak, Raymond H.; Rottmann, Joerg; Bryant, Jonathan H.; Williams, Christopher L.; Berbeco, Ross I.; Lewis, John H.; Li, Ruijiang

    2014-08-15

    Purpose: In this work the authors develop and investigate the feasibility of a method to estimate time-varying volumetric images from individual MV cine electronic portal image device (EPID) images. Methods: The authors adopt a two-step approach to time-varying volumetric image estimation from a single cine EPID image. In the first step, a patient-specific motion model is constructed from 4DCT. In the second step, parameters in the motion model are tuned according to the information in the EPID image. The patient-specific motion model is based on a compact representation of lung motion represented in displacement vector fields (DVFs). DVFs are calculated through deformable image registration (DIR) of a reference 4DCT phase image (typically peak-exhale) to a set of 4DCT images corresponding to different phases of a breathing cycle. The salient characteristics in the DVFs are captured in a compact representation through principal component analysis (PCA). PCA decouples the spatial and temporal components of the DVFs. Spatial information is represented in eigenvectors and the temporal information is represented by eigen-coefficients. To generate a new volumetric image, the eigen-coefficients are updated via cost function optimization based on digitally reconstructed radiographs and projection images. The updated eigen-coefficients are then multiplied with the eigenvectors to obtain updated DVFs that, in turn, give the volumetric image corresponding to the cine EPID image. Results: The algorithm was tested on (1) Eight digital eXtended CArdiac-Torso phantom datasets based on different irregular patient breathing patterns and (2) patient cine EPID images acquired during SBRT treatments. The root-mean-squared tumor localization error is (0.73 ± 0.63 mm) for the XCAT data and (0.90 ± 0.65 mm) for the patient data. Conclusions: The authors introduced a novel method of estimating volumetric time-varying images from single cine EPID images and a PCA-based lung motion model

  10. Dosimetric effect due to the motion during deep inspiration breath hold for left-sided breast cancer radiotherapy.

    PubMed

    Tang, Xiaoli; Cullip, Tim; Dooley, John; Zagar, Timothy; Jones, Ellen; Chang, Sha; Zhu, Xiaofeng; Lian, Jun; Marks, Lawrence

    2015-01-01

    Deep inspiration breath-hold (DIBH) radiotherapy for left-sided breast cancer can reduce cardiac exposure and internal motion. We modified our in-house treatment planning system (TPS) to retrospectively analyze breath-hold motion log files to calculate the dosimetric effect of the motion during breath hold. Thirty left-sided supine DIBH breast patients treated using AlignRT were studied. Breath-hold motion was recorded — three translational and three rotational displacements of the treatment surface — the Real Time Deltas (RTD). The corresponding delivered dose was estimated using the beam-on portions of the RTDs. Each motion was used to calculate dose, and the final estimated dose was the equally weighted average of the multiple resultant doses. Ten of thirty patients had internal mammary nodes (IMN) purposefully included in the tangential fields, and we evaluated the percentage of IMN covered by 40 Gy. The planned and delivered heart mean dose, lungs V20 (volume of the lungs receiving > 20 Gy), percentage of IMN covered by 40 Gy, and IMN mean dose were compared. The averaged mean and standard deviation of the beam-on portions of the absolute RTDs were 0.81 ± 1.29 mm, 0.68 ± 0.85mm, 0.76 ± 0.85 mm, 0.96° ± 0.49°, 0.93° ± 0.43°, and 1.03° ± 0.50°, for vertical, longitudinal, lateral, yaw, roll, and pitch, respectively. The averaged planned and delivered mean heart dose were 99 and 101 cGy. Lungs V20 were 6.59% and 6.74%. IMN 40 Gy coverage was 83% and 77%, and mean IMN dose was 4642 and 4518 cGy. The averaged mean motion during DIBH was smaller than 1 mm and 1°, which reflects the relative reproducibility of the patient breath hold. On average, the mean heart dose and lungs V20 were reasonably close to what have been planned. IMN 40 Gy coverage might be modestly reduced for certain cases. PMID:26219001

  11. Imaging two-dimensional displacements and strains in skeletal muscle during joint motion by cine DENSE MR.

    PubMed

    Zhong, Xiaodong; Epstein, Frederick H; Spottiswoode, Bruce S; Helm, Patrick A; Blemker, Silvia S

    2008-01-01

    The objective of this study was to apply cine magnetic resonance imaging (MRI) using displacement encoding with stimulated echoes (DENSE) to measure the dynamic two-dimensional (2D) displacement and Lagrangian strain fields in the biceps brachii muscle. Six healthy volunteers underwent cine DENSE MRI during repeated elbow flexion against the load of gravity. Displacement encoded dynamic images of the upper arm were acquired with spatial and temporal resolutions of 1.9 x 1.9 mm(2) and 30 ms, respectively. Pixel-wise Lagrangian displacement and strain fields were calculated from the measured images. We extracted the first and second principal strains (E1 and E2) along the centerline and anterior regions of the muscle. E1 and E2 were relatively uniform along the anterior region. However, E1 and E2 were both non-uniform along the centerline region-normalized values for E1 and E2 varied over the ranges of 0.27-1.35, and 0.45-2.36, respectively. The directions of the first and second principal strains varied throughout the muscle and showed that the direction of principal shortening is not necessarily aligned with fascicle direction. This study demonstrates the utility of cine DENSE MRI for analyzing skeletal muscle mechanics and provides data describing the in vivo mechanics of muscle tissue to a level of detail that has not been previously possible. PMID:18177655

  12. Dosimetric investigation of breath-hold intensity-modulated radiotherapy for pancreatic cancer

    SciTech Connect

    Nakamura, Mitsuhiro; Kishimoto, Shun; Iwamura, Kohei; Shiinoki, Takehiro; Nakamura, Akira; Matsuo, Yukinori; Shibuya, Keiko; Hiraoka, Masahiro

    2012-01-15

    Purpose: To experimentally investigate the effects of variations in respiratory motion during breath-holding (BH) at end-exhalation (EE) on intensity-modulated radiotherapy (BH-IMRT) dose distribution using a motor-driven base, films, and an ionization chamber. Methods: Measurements were performed on a linear accelerator, which has a 120-leaf independently moving multileaf collimator with 5-mm leaf width at the isocenter for the 20-cm central field. Polystyrene phantoms with dimensions of 40 x 40 x 10 cm were set on a motor-driven base. All gantry angles of seven IMRT plans (a total of 35 fields) were changed to zero, and doses were then delivered to a film placed at a depth of 4 cm and an ionization chamber at a depth of 5 cm in the phantom with a dose rate of 600 MU/min under the following conditions: pulsation from the abdominal aorta and baseline drift with speeds of 0.2 mm/s (BD{sub 0.2mm/s}) and 0.4 mm/s (BD{sub 0.4mm/s}). As a reference for comparison, doses were also delivered to the chamber and film under stationary conditions. Results: In chamber measurements, means {+-} standard deviations of the dose deviations between stationary and moving conditions were -0.52% {+-} 1.03% (range: -3.41-1.05%), -0.07% {+-} 1.21% (range: -1.88-4.31%), and 0.03% {+-} 1.70% (range: -2.70-6.41%) for pulsation, BD{sub 0.2mm/s}, and BD{sub 0.4mm/s}, respectively. The {gamma} passing rate ranged from 99.5% to 100.0%, even with the criterion of 2%/1 mm for pulsation pattern. In the case of BD{sub 0.4mm/s}, the {gamma} passing rate for four of 35 fields (11.4%) did not reach 90% with a criterion of 3%/3 mm. The differences in {gamma} passing rate between BD{sub 0.2mm/s} and BD{sub 0.4mm/s} were statistically significant for each criterion. Taking {gamma} passing rates of > 90% as acceptable with a criterion of 3%/3 mm, large differences were observed in the {gamma} passing rate between the baseline drift of {<=}5 mm and that of >5 mm (minimum {gamma} passing rate: 92.0% vs 82

  13. Deposition of Particles in the Alveolar Airways: Inhalation and Breath-Hold with Pharmaceutical Aerosols

    PubMed Central

    Khajeh-Hosseini-Dalasm, Navvab; Longest, P. Worth

    2014-01-01

    Previous studies have demonstrated that factors such as airway wall motion, inhalation waveform, and geometric complexity influence the deposition of aerosols in the alveolar airways. However, deposition fraction correlations are not available that account for these factors in determining alveolar deposition. The objective of this study was to generate a new space-filling model of the pulmonary acinus region and implement this model to develop correlations of aerosol deposition that can be used to predict the alveolar dose of inhaled pharmaceutical products. A series of acinar models was constructed containing different numbers of alveolar duct generations based on space-filling 14-hedron elements. Selected ventilation waveforms were quick-and-deep and slow-and-deep inhalation consistent with the use of most pharmaceutical aerosol inhalers. Computational fluid dynamics simulations were used to predict aerosol transport and deposition in the series of acinar models across various orientations with gravity where ventilation was driven by wall motion. Primary findings indicated that increasing the number of alveolar duct generations beyond 3 had a negligible impact on total acinar deposition, and total acinar deposition was not affected by gravity orientation angle. A characteristic model containing three alveolar duct generations (D3) was then used to develop correlations of aerosol deposition in the alveolar airways as a function of particle size and particle residence time in the geometry. An alveolar deposition parameter was determined in which deposition correlated with d2t over the first half of inhalation followed by correlation with dt2, where d is the aerodynamic diameter of the particles and t is the potential particle residence time in the alveolar model. Optimal breath-hold times to allow 95% deposition of inhaled 1, 2, and 3 μm particles once inside the alveolar region were approximately >10, 2.7, and 1.2 s, respectively. Coupling of the deposition

  14. Deposition of Particles in the Alveolar Airways: Inhalation and Breath-Hold with Pharmaceutical Aerosols.

    PubMed

    Khajeh-Hosseini-Dalasm, Navvab; Longest, P Worth

    2015-01-01

    Previous studies have demonstrated that factors such as airway wall motion, inhalation waveform, and geometric complexity influence the deposition of aerosols in the alveolar airways. However, deposition fraction correlations are not available that account for these factors in determining alveolar deposition. The objective of this study was to generate a new space-filling model of the pulmonary acinus region and implement this model to develop correlations of aerosol deposition that can be used to predict the alveolar dose of inhaled pharmaceutical products. A series of acinar models was constructed containing different numbers of alveolar duct generations based on space-filling 14-hedron elements. Selected ventilation waveforms were quick-and-deep and slow-and-deep inhalation consistent with the use of most pharmaceutical aerosol inhalers. Computational fluid dynamics simulations were used to predict aerosol transport and deposition in the series of acinar models across various orientations with gravity where ventilation was driven by wall motion. Primary findings indicated that increasing the number of alveolar duct generations beyond 3 had a negligible impact on total acinar deposition, and total acinar deposition was not affected by gravity orientation angle. A characteristic model containing three alveolar duct generations (D3) was then used to develop correlations of aerosol deposition in the alveolar airways as a function of particle size and particle residence time in the geometry. An alveolar deposition parameter was determined in which deposition correlated with d(2)t over the first half of inhalation followed by correlation with dt(2), where d is the aerodynamic diameter of the particles and t is the potential particle residence time in the alveolar model. Optimal breath-hold times to allow 95% deposition of inhaled 1, 2, and 3 μm particles once inside the alveolar region were approximately >10, 2.7, and 1.2 s, respectively. Coupling of the deposition

  15. Performance of simultaneous cardiac-respiratory self-gated three-dimensional MR imaging of the heart: initial experience.

    PubMed

    Manka, Robert; Buehrer, Martin; Boesiger, Peter; Fleck, Eckart; Kozerke, Sebastian

    2010-06-01

    This study was approved by the local institutional ethics committee, and informed consent was obtained from all volunteers and patients. The objective of the present study was to assess the performance of high-spatial-resolution three-dimensional prospective cardiac-respiratory self-gated (CRSG) magnetic resonance (MR) imaging for determining left ventricular (LV) volumes and mass, as well as right ventricular (RV) volumes, in comparison with standard electrocardiography (ECG)-triggered, two-dimensional multisection, multiple-breath-hold cine imaging. The self-gated method derives cardiac triggering and respiratory gating information prospectively on the basis of additional MR imaging signals acquired in every repetition time and, thereby, eliminates the need for ECG triggering and multiple-breath-hold procedures. Data were acquired in 15 healthy volunteers (mean age, 27.2 years +/- 7.2 [standard deviation]) and 11 patients (mean age, 60.7 years +/- 11.3). The bias between the self-gating and the reference imaging techniques was minimal for all LV and RV parameters (mean values: LV end-diastolic volume, 2.0 mL; LV end-systolic volume, 0.6 mL; RV end-diastolic volume, 2.2 mL; and RV end-systolic volume, 0.8 mL). Prospective CRSG is a valuable alternative to ECG-triggered, multisection, multiple-breath-hold cine imaging of the heart and holds considerable promise for simplifying functional imaging of the heart, particularly in patients who are unable to hold their breath for a long period and patients who show ECG signal disturbances. PMID:20501728

  16. Cine and tagged cardiovascular magnetic resonance imaging in normal rat at 1.5 T: a rest and stress study

    PubMed Central

    Daire, Jean-Luc; Jacob, Jean-Pascal; Hyacinthe, Jean-Noel; Croisille, Pierre; Montet-Abou, Karin; Richter, Sophie; Botsikas, Diomidis; Lepetit-Coiffé, Matthieu; Morel, Denis; Vallée, Jean-Paul

    2008-01-01

    Background The purpose of this study was to measure regional contractile function in the normal rat using cardiac cine and tagged cardiovascular magnetic resonance (CMR) during incremental low doses of dobutamine and at rest. Methods Five rats were investigated for invasive left ventricle pressure measurements and five additional rats were imaged on a clinical 1.5 T MR system using a cine sequence (11–20 phases per cycle, 0.28/0.28/2 mm) and a C-SPAMM tag sequence (18–25 phases per cycle, 0.63/1.79/3 mm, tag spacing 1.25 mm). For each slice, wall thickening (WT) and circumferential strains (CS) were calculated at rest and at stress (2.5, 5 and 10 μg/min/kg of dobutamine). Results Good cine and tagged images were obtained in all the rats even at higher heart rate (300–440 bpm). Ejection fraction and left ventricular (LV) end-systolic volume showed significant changes after each dobutamine perfusion dose (p < 0.001). Tagged CMR had the capacity to resolve the CS transmural gradient and showed a significant increase of both WT and CS at stress compared to rest. Intra and interobserver study showed less variability for the tagged technique. In rats in which a LV catheter was placed, dobutamine produced a significant increase of heart rate, LV dP/dtmax and LV pressure significantly already at the lowest infusion dose. Conclusion Robust cardiac cine and tagging CMR measurements can be obtained in the rat under incremental dobutamine stress using a clinical 1.5 T MR scanner. PMID:18980685

  17. Fast Determination of Flip Angle and T1 in Hyperpolarized Gas MRI During a Single Breath-Hold

    NASA Astrophysics Data System (ADS)

    Zhong, Jianping; Ruan, Weiwei; Han, Yeqing; Sun, Xianping; Ye, Chaohui; Zhou, Xin

    2016-05-01

    MRI of hyperpolarized media, such as 129Xe and 3He, shows great potential for clinical applications. The optimal use of the available spin polarization requires accurate flip angle calibrations and T1 measurements. Traditional flip angle calibration methods are time-consuming and suffer from polarization losses during T1 relaxation. In this paper, we propose a method to simultaneously calibrate flip angles and measure T1 in vivo during a breath-hold time of less than 4 seconds. We demonstrate the accuracy, robustness and repeatability of this method and contrast it with traditional methods. By measuring the T1 of hyperpolarized gas, the oxygen pressure in vivo can be calibrated during the same breath hold. The results of the calibration have been applied in variable flip angle (VFA) scheme to obtain a stable steady-state transverse magnetization. Coupled with this method, the ultra-short TE (UTE) and constant VFA (CVFA) schemes are expected to give rise to new applications of hyperpolarized media.

  18. Fast Determination of Flip Angle and T1 in Hyperpolarized Gas MRI During a Single Breath-Hold

    PubMed Central

    Zhong, Jianping; Ruan, Weiwei; Han, Yeqing; Sun, Xianping; Ye, Chaohui; Zhou, Xin

    2016-01-01

    MRI of hyperpolarized media, such as 129Xe and 3He, shows great potential for clinical applications. The optimal use of the available spin polarization requires accurate flip angle calibrations and T1 measurements. Traditional flip angle calibration methods are time-consuming and suffer from polarization losses during T1 relaxation. In this paper, we propose a method to simultaneously calibrate flip angles and measure T1 in vivo during a breath-hold time of less than 4 seconds. We demonstrate the accuracy, robustness and repeatability of this method and contrast it with traditional methods. By measuring the T1 of hyperpolarized gas, the oxygen pressure in vivo can be calibrated during the same breath hold. The results of the calibration have been applied in variable flip angle (VFA) scheme to obtain a stable steady-state transverse magnetization. Coupled with this method, the ultra-short TE (UTE) and constant VFA (CVFA) schemes are expected to give rise to new applications of hyperpolarized media. PMID:27169670

  19. Quality Assurance Challenges for Motion-Adaptive Radiation Therapy: Gating, Breath Holding, and Four-Dimensional Computed Tomography

    SciTech Connect

    Jiang, Steve B. Wolfgang, John; Mageras, Gig S.

    2008-05-01

    Compared with conventional three-dimensional (3D) conformal radiation therapy and intensity-modulated radiation therapy treatments, quality assurance (QA) for motion-adaptive radiation therapy involves various challenges because of the added temporal dimension. Here we discuss those challenges for three specific techniques related to motion-adaptive therapy: namely respiratory gating, breath holding, and four-dimensional computed tomography. Similar to the introduction of any other new technologies in clinical practice, typical QA measures should be taken for these techniques also, including initial testing of equipment and clinical procedures, as well as frequent QA examinations during the early stage of implementation. Here, rather than covering every QA aspect in depth, we focus on some major QA challenges. The biggest QA challenge for gating and breath holding is how to ensure treatment accuracy when internal target position is predicted using external surrogates. Recommended QA measures for each component of treatment, including simulation, planning, patient positioning, and treatment delivery and verification, are discussed. For four-dimensional computed tomography, some major QA challenges have also been discussed.

  20. Fast Determination of Flip Angle and T1 in Hyperpolarized Gas MRI During a Single Breath-Hold.

    PubMed

    Zhong, Jianping; Ruan, Weiwei; Han, Yeqing; Sun, Xianping; Ye, Chaohui; Zhou, Xin

    2016-01-01

    MRI of hyperpolarized media, such as (129)Xe and (3)He, shows great potential for clinical applications. The optimal use of the available spin polarization requires accurate flip angle calibrations and T1 measurements. Traditional flip angle calibration methods are time-consuming and suffer from polarization losses during T1 relaxation. In this paper, we propose a method to simultaneously calibrate flip angles and measure T1 in vivo during a breath-hold time of less than 4 seconds. We demonstrate the accuracy, robustness and repeatability of this method and contrast it with traditional methods. By measuring the T1 of hyperpolarized gas, the oxygen pressure in vivo can be calibrated during the same breath hold. The results of the calibration have been applied in variable flip angle (VFA) scheme to obtain a stable steady-state transverse magnetization. Coupled with this method, the ultra-short TE (UTE) and constant VFA (CVFA) schemes are expected to give rise to new applications of hyperpolarized media. PMID:27169670

  1. Clinico-laboratory profile of breath-holding spells in children in Sohag University Hospital, Upper Egypt

    PubMed Central

    Sadek, Abdelrahim Abdrabou; Mohamed, Montaser Mohamed; Sharaf, El-Zahraa El-Said Ahmed; Magdy, Rofaida Mohamed; Allam, Ahmed Ahmed

    2016-01-01

    Introduction Breath-holding spells (BHSs) are involuntary pauses of breathing, sometimes accompanied by loss of consciousness. They usually occur in response to an upsetting or surprising situation. Breath-holding spells are usually caused by either a change in the usual breathing pattern or a slowing of the heart rate. In some children, BHSs may be related to iron deficiency anemia. The aim of the work was to study the clinical and laboratory profile of BPHs in children presented to the Neuropediatric Clinic at Sohag University Hospital. Methods An observational prospective study was done at Sohag University Hospital over a period of one year on children diagnosed as having BHSs by clinical history and laboratory evaluation, including complete blood count (CBC), serum iron, serum ferritin, total iron binding capacity, and Electroencephalography (EEG). Results During the period of study (one year), we reviewed data of 32 children who had been diagnosed as having BHSs. We found that cyanotic spells (71.88%) predominated over pallid spells. There were positive family histories (31.25%) and consanguinity (53.135) in the studied patients. We found a high incidence of iron deficiency anemia (62.5%) in association with BHS. Abnormal EEGs were found in (65.63%) of studied children. Conclusion BHS is a common, important problem associated with iron deficiency anemia, which is, in turn, a common nutritional problem in our country. PMID:27279996

  2. Passive flooding of paranasal sinuses and middle ears as a method of equalisation in extreme breath-hold diving.

    PubMed

    Germonpré, Peter; Balestra, Costantino; Musimu, Patrick

    2011-06-01

    Breath-hold diving is both a recreational activity, performed by thousands of enthusiasts in Europe, and a high-performance competitive sport. Several 'disciplines' exist, of which the 'no-limits' category is the most spectacular: using a specially designed heavy 'sled,' divers descend to extreme depths on a cable, and then reascend using an inflatable balloon, on a single breath. The current world record for un-assisted descent stands at more than 200 m of depth. Equalising air pressure in the paranasal sinuses and middle-ear cavities is a necessity during descent to avoid barotraumas. However, this requires active insufflations of precious air, which is thus unavailable in the pulmonary system. The authors describe a diver who, by training, is capable of allowing passive flooding of the sinuses and middle ear with (sea) water during descent, by suppressing protective (parasympathetic) reflexes during this process. Using this technique, he performed a series of extreme-depth breath-hold dives in June 2005, descending to 209 m of sea water on one breath of air. PMID:20961916

  3. Computerized method for estimation of the location of a lung tumor on EPID cine images without implanted markers in stereotactic body radiotherapy

    NASA Astrophysics Data System (ADS)

    Arimura, H.; Egashira, Y.; Shioyama, Y.; Nakamura, K.; Yoshidome, S.; Anai, S.; Nomoto, S.; Honda, H.; Toyofuku, F.; Higashida, Y.; Onizuka, Y.; Terashima, H.

    2009-02-01

    The purpose of this study was to develop a computerized method for estimation of the location of a lung tumor in cine images on an electronic portal imaging device (EPID) without implanted markers during stereotactic body radiotherapy (SBRT). Each tumor region was segmented in the first EPID cine image, i.e., reference portal image, based on a multiple-gray level thresholding technique and a region growing technique, and then the image including the tumor region was cropped as a 'tumor template' image. The tumor location was determined as the position in which the tumor template image took the maximum cross-correlation value within each consecutive portal image, which was acquired in cine mode on the EPID in treatment. EPID images with 512 × 384 pixels (pixel size: 0.56 mm) were acquired at a sampling rate of 0.5 frame s-1 by using energies of 4, 6 or 10 MV on linear accelerators. We applied our proposed method to EPID cine images (226 frames) of 12 clinical cases (ages: 51-83, mean: 72) with a non-small cell lung cancer. As a result, the average location error between tumor points obtained by our method and the manual method was 1.47 ± 0.60 mm. This preliminary study suggests that our method based on the tumor template matching technique might be feasible for tracking the location of a lung tumor without implanted markers in SBRT.

  4. Quantification of lung tumor rotation with automated landmark extraction using orthogonal cine MRI images

    NASA Astrophysics Data System (ADS)

    Paganelli, Chiara; Lee, Danny; Greer, Peter B.; Baroni, Guido; Riboldi, Marco; Keall, Paul

    2015-09-01

    The quantification of tumor motion in sites affected by respiratory motion is of primary importance to improve treatment accuracy. To account for motion, different studies analyzed the translational component only, without focusing on the rotational component, which was quantified in a few studies on the prostate with implanted markers. The aim of our study was to propose a tool able to quantify lung tumor rotation without the use of internal markers, thus providing accurate motion detection close to critical structures such as the heart or liver. Specifically, we propose the use of an automatic feature extraction method in combination with the acquisition of fast orthogonal cine MRI images of nine lung patients. As a preliminary test, we evaluated the performance of the feature extraction method by applying it on regions of interest around (i) the diaphragm and (ii) the tumor and comparing the estimated motion with that obtained by (i) the extraction of the diaphragm profile and (ii) the segmentation of the tumor, respectively. The results confirmed the capability of the proposed method in quantifying tumor motion. Then, a point-based rigid registration was applied to the extracted tumor features between all frames to account for rotation. The median lung rotation values were  -0.6   ±   2.3° and  -1.5   ±   2.7° in the sagittal and coronal planes respectively, confirming the need to account for tumor rotation along with translation to improve radiotherapy treatment.

  5. International Reproducibility of Single Breath-hold T2* Magnetic Resonance for Cardiac and Liver Iron Assessment among Five Thalassemia Centers

    PubMed Central

    Kirk, Paul; He, Taigang; Anderson, Lisa J; Roughton, Michael; Tanner, Mark A; Lam, Wynnie WM; Au, Wing Y; Chu, Winnie CW; Chan, Godfrey; Galanello, Renzo; Matta, Gildo; Fogel, Mark; Cohen, Alan R; Tan, Ru San; Chen, Kevin; Ng, Ivy; Lai, Angi; Fucharoen, Suthat; Laothamata, Jiraporn; Chuncharunee, Suporn; Jongjirasiri, Sutipong; Firmin, David N; Smith, Gillian C; Pennell, Dudley J

    2010-01-01

    Purpose To examine the reproducibility of the single breath-hold T2* technique from different scanners, after installation of standard methodology in 5 international centers. Materials and Methods Up to 10 patients from each center were scanned twice locally for local interstudy reproducibility of heart and liver T2*, and then flown to a central MR facility to be rescanned on a reference scanner for intercenter reproducibility. Interobserver reproducibility for all scans was also assessed. Results Of the 49 patients scanned, the intercenter reproducibility for T2* was 5.9% for the heart and 5.8% for the liver. Local interstudy reproducibility for T2* was 7.4% for the heart and 4.6% for the liver. Interobserver reproducibility for T2* was 5.4% for the heart and 4.4% for the liver. Conclusion These data indicate that T2* MR may be developed into a widespread test for tissue siderosis providing that well defined and approved imaging and analysis techniques are used. PMID:20677256

  6. SU-E-J-211: Design and Study of In-House Software Based Respiratory Motion Monitoring, Controlling and Breath-Hold Device for Gated Radiotherapy

    SciTech Connect

    Shanmugam, Senthilkumar

    2014-06-01

    Purpose: The purpose of this present work was to fabricate an in-house software based respiratory monitoring, controlling and breath-hold device using computer software programme which guides the patient to have uniform breath hold in response to request during the gated radiotherapy. Methods: The respiratory controlling device consists of a computer, inhouse software, video goggles, a highly sensitive sensor for measurement of distance, mounting systems, a camera, a respiratory signal device, a speaker and a visual indicator. The computer is used to display the respiratory movements of the patient with digital as well as analogue respiration indicators during the respiration cycle, to control, breath-hold and analyze the respiratory movement using indigenously developed software. Results: Studies were conducted with anthropomophic phantoms by simulating the respiratory motion on phantoms and recording the respective movements using the respiratory monitoring device. The results show good agreement between the simulated and measured movements. Further studies were conducted for 60 cancer patients with several types of cancers in the thoracic region. The respiratory movement cycles for each fraction of radiotherapy treatment were recorded and compared. Alarm indications are provided in the system to indicate when the patient breathing movement exceeds the threshold level. This will help the patient to maintain uniform breath hold during the radiotherapy treatment. Our preliminary clinical test results indicate that our device is highly reliable and able to maintain the uniform respiratory motion and breathe hold during the entire course of gated radiotherapy treatment. Conclusion: An indigenous respiratory monitoring device to guide the patient to have uniform breath hold device was fabricated. The alarm feature and the visual waveform indicator in the system guide the patient to have normal respiration. The signal from the device can be connected to the radiation

  7. Clinical Feasibility of Using an EPID in cine Mode for Image-Guided Verification of Stereotactic Body Radiotherapy

    SciTech Connect

    Berbeco, Ross I.

    2007-09-01

    Purpose: To introduce a novel method for monitoring tumor location during stereotactic body radiotherapy (SBRT) while the treatment beam is on by using a conventional electronic portal imaging device (EPID). Methods and Materials: In our clinic, selected patients were treated under a phase I institutional review board-approved SBRT protocol for limited hepatic metastases from solid tumors. Before treatment planning multiple gold fiducial markers were implanted on the periphery of the tumor. During treatment the EPID was used in cine mode to collect the exit radiation and produce a sequence of images for each field. An in-house program was developed for calculating the location of the fiducials and their relative distance to the planned locations. Results: Three case studies illustrate the utility of the technique. Patient A exhibited a systematic shift of 4 mm during one of the treatment beams. Patient B showed an inferior drift of the target of approximately 1 cm from the time of setup to the end of the fraction. Patient C had a poor setup on the first day of treatment that was quantified and accounted for on subsequent treatment days. Conclusions: Target localization throughout each treatment beam can be quickly assessed with the presented technique. Treatment monitoring with an EPID in cine mode is shown to be a clinically feasible and useful tool.

  8. Fast cine-magnetic resonance imaging point tracking for prostate cancer radiation therapy planning

    NASA Astrophysics Data System (ADS)

    Dowling, J.; Dang, K.; Fox, Chris D.; Chandra, S.; Gill, Suki; Kron, T.; Pham, D.; Foroudi, F.

    2014-03-01

    The analysis of intra-fraction organ motion is important for improving the precision of radiation therapy treatment delivery. One method to quantify this motion is for one or more observers to manually identify anatomic points of interest (POIs) on each slice of a cine-MRI sequence. However this is labour intensive and inter- and intra- observer variation can introduce uncertainty. In this paper a fast method for non-rigid registration based point tracking in cine-MRI sagittal and coronal series is described which identifies POIs in 0.98 seconds per sagittal slice and 1.35 seconds per coronal slice. The manual and automatic points were highly correlated (r>0.99, p<0.001) for all organs and the difference generally less than 1mm. For prostate planning peristalsis and rectal gas can result in unpredictable out of plane motion, suggesting the results may require manual verification.

  9. SU-E-J-140: Availability of Using Diaphragm Matching in Stereotactic Body Radiotherapy (SBRT) at the Time in Breath-Holding SBRT for Liver Cancer

    SciTech Connect

    Kawahara, D; Tsuda, S.; Ozawa, S; Ohno, Y.; Kimura, T.; Nagata, Y.; Nakashima, T.; Aita, M.; Ochi, Y.; Okumura, T.; Masuda, H.

    2014-06-01

    Purpose: IGRT based on the bone matching may produce a larger target positioning error in terms of the reproducibility of the expiration breath hold. Therefore, the feasibility of the 3D image matching between planning CT image and pretreatment CBCT image based on the diaphragm matching was investigated. Methods: In fifteen-nine liver SBRT cases, Lipiodol, uptake after TACE was outlined as the marker of the tumor. The relative coordinate of the isocenter obtained by the contrast matching was defined as the reference coordinate. The target positioning difference between diaphragm matching and bone matching were evaluated by the relative coordinate of the isocenter from the reference coordinate obtained by each matching technique. In addition, we evaluated PTV margins by van Herk setup margin formula. Results: The target positioning error by the diaphragm matching and the bone matching was 1.31±0.83 and 3.10±2.80 mm in the cranial-caudal(C-C) direction, 1.04±0.95 and 1.62±1.02 mm in the anterior-posterior(A-P) direction, 0.93±1.19 and 1.12±0.94 mm in the left-right(L-R) direction, respectively. The positioning error by the diaphragm matching was significantly smaller than the bone matching in the C-C direction (p<0.05). The setup margin of diaphragm matching and bone matching that we had calculated based on van Herk margin formula was 4.5mm and 6.2mm(C-C), and 3.6mm and 6.3mm(A-P), and 2.6mm and 4.5mm(L-R), respectively. Conclusion: IGRT based on a diaphragm matching could be one alternative image matching technique for the positioning of the patients with liver tumor.

  10. NOTE: Dosimetric evaluation of inspiration and expiration breath-hold for intensity-modulated radiotherapy planning of non-small cell lung cancer

    NASA Astrophysics Data System (ADS)

    Tahir, Bilal A.; Bragg, Christopher M.; Lawless, Sarah E.; Hatton, Matthew Q. F.; Ireland, Rob H.

    2010-04-01

    The purpose of this study was to compare target coverage and lung tissue sparing between inspiration and expiration breath-hold intensity-modulated radiotherapy (IMRT) plans for patients with non-small cell lung cancer (NSCLC). In a prospective study, seven NSCLC patients gave written consent to undergo both moderate deep inspiration and end-expiration breath-hold computed tomography (CT), which were used to generate five-field IMRT plans. Dose was calculated with a scatter and an inhomogeneity correction algorithm. The percentage of the planning target volume (PTV) receiving 90% of the prescription dose (PTV90), the volume of total lung receiving >= 10 Gy (V10) and >= 20 Gy (V20) and the mean lung dose (MLD) were compared by the Student's paired t-test. Compared with the expiration plans, the mean ± SD reductions for V10, V20 and MLD on the inspiration plans were 4.0 ± 3.7% (p = 0.031), 2.5 ± 2.3% (p = 0.028) and 1.1 ± 0.7 Gy (p = 0.007), respectively. Conversely, a mean difference of 1.1 ± 1.1% (p = 0.044) in PTV90 was demonstrated in favour of expiration. When using IMRT, inspiration breath-hold can reduce the dose to normal lung tissue while expiration breath-hold can improve the target coverage. The improved lung sparing at inspiration may outweigh the modest improvements in target coverage at expiration.

  11. Development and clinical evaluation of automatic fiducial detection for tumor tracking in cine megavoltage images during volumetric modulated arc therapy

    PubMed Central

    Azcona, Juan Diego; Li, Ruijiang; Mok, Edward; Hancock, Steven; Xing, Lei

    2013-01-01

    Purpose: Real-time tracking of implanted fiducials in cine megavoltage (MV) imaging during volumetric modulated arc therapy (VMAT) delivery is complicated due to the inherent low contrast of MV images and potential blockage of dynamic leaves configurations. The purpose of this work is to develop a clinically practical autodetection algorithm for motion management during VMAT. Methods: The expected field-specific segments and the planned fiducial position from the Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system were projected onto the MV images. The fiducials were enhanced by applying a Laplacian of Gaussian filter in the spatial domain for each image, with a blob-shaped object as the impulse response. The search of implanted fiducials was then performed on a region of interest centered on the projection of the fiducial when it was within an open field including the case when it was close to the field edge or partially occluded by the leaves. A universal template formula was proposed for template matching and normalized cross correlation was employed for its simplicity and computational efficiency. The search region for every image was adaptively updated through a prediction model that employed the 3D position of the fiducial estimated from the localized positions in previous images. This prediction model allowed the actual fiducial position to be tracked dynamically and was used to initialize the search region. The artifacts caused by electronic interference during the acquisition were effectively removed. A score map was computed by combining both morphological information and image intensity. The pixel location with the highest score was selected as the detected fiducial position. The sets of cine MV images taken during treatment were analyzed with in-house developed software written in MATLAB (The Mathworks, Inc., Natick, MA). Five prostate patients were analyzed to assess the algorithm performance by measuring their positioning

  12. Development and clinical evaluation of automatic fiducial detection for tumor tracking in cine megavoltage images during volumetric modulated arc therapy

    SciTech Connect

    Azcona, Juan Diego; Li Ruijiang; Mok, Edward; Hancock, Steven; Xing Lei

    2013-03-15

    Purpose: Real-time tracking of implanted fiducials in cine megavoltage (MV) imaging during volumetric modulated arc therapy (VMAT) delivery is complicated due to the inherent low contrast of MV images and potential blockage of dynamic leaves configurations. The purpose of this work is to develop a clinically practical autodetection algorithm for motion management during VMAT. Methods: The expected field-specific segments and the planned fiducial position from the Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system were projected onto the MV images. The fiducials were enhanced by applying a Laplacian of Gaussian filter in the spatial domain for each image, with a blob-shaped object as the impulse response. The search of implanted fiducials was then performed on a region of interest centered on the projection of the fiducial when it was within an open field including the case when it was close to the field edge or partially occluded by the leaves. A universal template formula was proposed for template matching and normalized cross correlation was employed for its simplicity and computational efficiency. The search region for every image was adaptively updated through a prediction model that employed the 3D position of the fiducial estimated from the localized positions in previous images. This prediction model allowed the actual fiducial position to be tracked dynamically and was used to initialize the search region. The artifacts caused by electronic interference during the acquisition were effectively removed. A score map was computed by combining both morphological information and image intensity. The pixel location with the highest score was selected as the detected fiducial position. The sets of cine MV images taken during treatment were analyzed with in-house developed software written in MATLAB (The Mathworks, Inc., Natick, MA). Five prostate patients were analyzed to assess the algorithm performance by measuring their positioning

  13. SU-E-J-112: The Impact of Cine EPID Image Acquisition Frame Rate On Markerless Soft-Tissue Tracking

    SciTech Connect

    Yip, S; Rottmann, J; Berbeco, R

    2014-06-01

    Purpose: Although reduction of the cine EPID acquisition frame rate through multiple frame averaging may reduce hardware memory burden and decrease image noise, it can hinder the continuity of soft-tissue motion leading to poor auto-tracking results. The impact of motion blurring and image noise on the tracking performance was investigated. Methods: Phantom and patient images were acquired at a frame rate of 12.87Hz on an AS1000 portal imager. Low frame rate images were obtained by continuous frame averaging. A previously validated tracking algorithm was employed for auto-tracking. The difference between the programmed and auto-tracked positions of a Las Vegas phantom moving in the superior-inferior direction defined the tracking error (δ). Motion blurring was assessed by measuring the area change of the circle with the greatest depth. Additionally, lung tumors on 1747 frames acquired at eleven field angles from four radiotherapy patients are manually and automatically tracked with varying frame averaging. δ was defined by the position difference of the two tracking methods. Image noise was defined as the standard deviation of the background intensity. Motion blurring and image noise were correlated with δ using Pearson correlation coefficient (R). Results: For both phantom and patient studies, the auto-tracking errors increased at frame rates lower than 4.29Hz. Above 4.29Hz, changes in errors were negligible with δ<1.60mm. Motion blurring and image noise were observed to increase and decrease with frame averaging, respectively. Motion blurring and tracking errors were significantly correlated for the phantom (R=0.94) and patient studies (R=0.72). Moderate to poor correlation was found between image noise and tracking error with R -0.58 and -0.19 for both studies, respectively. Conclusion: An image acquisition frame rate of at least 4.29Hz is recommended for cine EPID tracking. Motion blurring in images with frame rates below 4.39Hz can substantially reduce the

  14. Implementation of Feedback-Guided Voluntary Breath-Hold Gating for Cone Beam CT-Based Stereotactic Body Radiotherapy

    SciTech Connect

    Peng Yong; Vedam, Sastry; Chang, Joe Y.; Gao Song; Sadagopan, Ramaswamy; Bues, Martin; Balter, Peter

    2011-07-01

    Purpose: To analyze tumor position reproducibility of feedback-guided voluntary deep inspiration breath-hold (FGBH) gating for cone beam computed tomography (CBCT)-based stereotactic body radiotherapy (SBRT). Methods and materials: Thirteen early-stage lung cancer patients eligible for SBRT with tumor motion of >1cm were evaluated for FGBH-gated treatment. Multiple FGBH CTs were acquired at simulation, and single FGBH CBCTs were also acquired prior to each treatment. Simulation CTs and treatment CBCTs were analyzed to quantify reproducibility of tumor positions during FGBH. Benefits of FGBH gating compared to treatment during free breathing, as well treatment with gating at exhalation, were examined for lung sparing, motion margins, and reproducibility of gross tumor volume (GTV) position relative to nonmoving anatomy. Results: FGBH increased total lung volumes by 1.5 times compared to free breathing, resulting in a proportional drop in total lung volume receiving 10 Gy or more. Intra- and inter-FGBH reproducibility of GTV centroid positions at simulation were 1.0 {+-} 0.5 mm, 1.3 {+-} 1.0 mm, and 0.6 {+-} 0.4 mm in the anterior-posterior (AP), superior-inferior (SI), and left-right lateral (LR) directions, respectively, compared to more than 1 cm of tumor motion at free breathing. During treatment, inter-FGBH reproducibility of the GTV centroid with respect to bony anatomy was 1.2 {+-} 0.7 mm, 1.5 {+-} 0.8 mm, and 1.0 {+-} 0.4 mm in the AP, SI, and LR directions. In addition, the quality of CBCTs was improved due to elimination of motion artifacts, making this technique attractive for poorly visualized tumors, even with small motion. Conclusions: The extent of tumor motion at normal respiration does not influence the reproducibility of the tumor position under breath hold conditions. FGBH-gated SBRT with CBCT can improve the reproducibility of GTV centroids, reduce required margins, and minimize dose to normal tissues in the treatment of mobile tumors.

  15. Application of the Karhunen-Loeve transform temporal image filter to reduce noise in real-time cardiac cine MRI.

    PubMed

    Ding, Yu; Chung, Yiu-Cho; Raman, Subha V; Simonetti, Orlando P

    2009-06-21

    Real-time dynamic magnetic resonance imaging (MRI) typically sacrifices the signal-to-noise ratio (SNR) to achieve higher spatial and temporal resolution. Spatial and/or temporal filtering (e.g., low-pass filtering or averaging) of dynamic images improves the SNR at the expense of edge sharpness. We describe the application of a temporal filter for dynamic MR image series based on the Karhunen-Loeve transform (KLT) to remove random noise without blurring stationary or moving edges and requiring no training data. In this paper, we present several properties of this filter and their effects on filter performance, and propose an automatic way to find the filter cutoff based on the autocorrelation of the eigenimages. Numerical simulation and in vivo real-time cardiac cine MR image series spanning multiple cardiac cycles acquired using multi-channel sensitivity-encoded MRI, i.e., parallel imaging, are used to validate and demonstrate these properties. We found that in this application, the noise standard deviation was reduced to 42% of the original with no apparent image blurring by using the proposed filter cutoff. Greater noise reduction can be achieved by increasing the length of the image series. This advantage of KLT filtering provides flexibility in the form of another scan parameter to trade for SNR. PMID:19491455

  16. The cardiac dose-sparing benefits of deep inspiration breath-hold in left breast irradiation: a systematic review

    SciTech Connect

    Smyth, Lloyd M; Knight, Kellie A; Aarons, Yolanda K; Wasiak, Jason

    2015-03-15

    Despite technical advancements in breast radiation therapy, cardiac structures are still subject to significant levels of irradiation. As the use of adjuvant radiation therapy after breast-conserving surgery continues to improve survival for early breast cancer patients, the associated radiation-induced cardiac toxicities become increasingly relevant. Our primary aim was to evaluate the cardiac-sparing benefits of the deep inspiration breath-hold (DIBH) technique. An electronic literature search of the PubMed database from 1966 to July 2014 was used to identify articles published in English relating to the dosimetric benefits of DIBH. Studies comparing the mean heart dose of DIBH and free breathing treatment plans for left breast cancer patients were eligible to be included in the review. Studies evaluating the reproducibility and stability of the DIBH technique were also reviewed. Ten studies provided data on the benefits of DIBH during left breast irradiation. From these studies, DIBH reduced the mean heart dose by up to 3.4 Gy when compared to a free breathing approach. Four studies reported that the DIBH technique was stable and reproducible on a daily basis. According to current estimates of the excess cardiac toxicity associated with radiation therapy, a 3.4 Gy reduction in mean heart dose is equivalent to a 13.6% reduction in the projected increase in risk of heart disease. DIBH is a reproducible and stable technique for left breast irradiation showing significant promise in reducing the late cardiac toxicities associated with radiation therapy.

  17. Efficacy of a Brief Psychoeducational Intervention for Mothers of Children with Breath-Holding Spells: A Randomized Controlled Pilot Trial.

    PubMed

    Bolat, Nurullah; Eliacik, Kayi; Sargin, Enis; Kanik, Ali; Baydan, Figen; Sarioglu, Berrak

    2016-08-01

    Objective Mothers of individuals with breath-holding spells (BHS) suffer more often from anxiety and experience more stressors in their everyday life. The purpose of this study was to examine the efficacy of psychoeducational intervention in reducing BHS and coping with these spells. Participants and Methods Mothers who have children with BHS were randomly assigned to one of the two groups: an intervention group receiving psychoeducational therapy in addition to the routine follow-up (n = 31) and a control group who did not receive psychoeducation in their routine follow-up (n = 28). The data collected at the beginning of the study and at the end of 3rd and 6th months about the frequency of the spells per month, maternal anxiety, and depression levels and mothers' perceived self-knowledge about coping BHS of both groups were compared. Results Mothers in psychoeducation group, compared with controls, improved significantly on state anxiety, depression, perceived anticipation anxiety level for BHS of their children and self-knowledge about coping with the spells. Conclusion The intervention program had a positive effect on anxiety-depression levels of the mothers and the frequency of BHS among the children. The possible link between emotional and autonomic dysregulation in children with BHS and maternal mental health were discussed. PMID:27128727

  18. Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

    NASA Astrophysics Data System (ADS)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-01-01

    A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p < 0.05). In addition, the presence of artifacts, the image clarity and the overall image quality were excellent at TE = 128 msec (p < 0.05). In abdominal MRI, the breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

  19. Exposure Range For Cine Radiographic Procedures

    NASA Astrophysics Data System (ADS)

    Moore, Robert J.

    1980-08-01

    Based on the author's experience, state-of-the-art cine radiographic equipment of the type used in modern cardiovascular laboratories for selective coronary arteriography must perform at well-defined levels to produce cine images with acceptable quantum mottle, contrast, and detail, as judged by consensus of across section of American cardiologists/radiologists experienced in viewing such images. Accordingly, a "standard" undertable state-of-the-art cine radiographic imaging system is postulated to answer the question of what patient exposure range is necessary to obtain cine images of acceptable quality. It is shown that such a standard system would be expected to produce a 'tabletop exposure of about 25 milliRoentgens per frame for the "standard" adult patient, plus-or-minus 33% for accept-able variation of system parameters. This means that for cine radiography at 60 frames per second (30 frames per second) the exposure rate range based on this model is 60 to 120 Roentgens per minute (30 to 60 Roentgens per minute). The author contends that studies at exposure levels below these will yield cine images of questionable diagnostic value; studies at exposure levels above these may yield cine images of excellent visual quality but having little additional diagnostic value, at the expense of added patient/personnel radiation exposure and added x-ray tube heat loading.

  20. Relationship between coronary flow reserve evaluated by phase-contrast cine cardiovascular magnetic resonance and serum eicosapentaenoic acid

    PubMed Central

    2013-01-01

    Background Long-term intake of long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs), especially eicosapentaenoic acid (EPA) is associated with a low risk for cardiovascular disease. Phase-contrast cine cardiovascular magnetic resonance (PC cine CMR) can assess coronary flow reserve (CFR). The present study investigates the relationship between CFR evaluated by PC cine CMR and the serum EPA. Methods We studied 127 patients (male, 116 (91%); mean age, 72.2 ± 7.4 years) with known or suspected coronary artery disease (CAD). X-ray coronary angiography revealed no significant coronary arterial stenoses (defined as luminal diameter reduction ≥50% on quantitative coronary angiogram (QCA) analysis) in all study participants. Breath-hold PC cine CMR images of the coronary sinus (CS) were acquired to assess blood flow of the CS both at rest and during adenosine triphosphate (ATP) infusion. We calculated CFR as CS blood flow during ATP infusion divided by that at rest. Patients were allocated to groups according to whether they had high (n = 64, EPA ≥ 75.8 μg/mL) or low (n = 63, EPA < 75.8 μg/mL) median serum EPA. Results CFR was significantly lower in the low, than in the high EPA group (2.54 ± 1.00 vs. 2.91 ± 0.98, p = 0.038). Serum EPA positively correlated with CFR (R = 0.35, p < 0.001). We defined preserved CFR as > 2.5, which is the previously reported lower limit of normal flow reserve without obstructive CAD. Multivariate analysis revealed that EPA is an independent predictor of CFR > 2.5 (odds ratio, 1.01; 95% confidence interval, 1.00 – 1.02, p = 0.008). Conclusions The serum EPA is significantly correlated with CFR in CAD patients without significant coronary artery stenosis. PMID:24359564

  1. Breath holding spell

    MedlinePlus

    ... children with: Genetic conditions, such as Riley-Day syndrome or Rett syndrome Iron deficiency anemia A family history of breath ... Editorial team. Related MedlinePlus Health Topics Breathing Problems Rett Syndrome Browse the Encyclopedia A.D.A.M., Inc. ...

  2. Minimizing Late Effects for Patients With Mediastinal Hodgkin Lymphoma: Deep Inspiration Breath-Hold, IMRT, or Both?

    SciTech Connect

    Aznar, Marianne C.; Maraldo, Maja V.; Schut, Deborah A.; Lundemann, Michael; Brodin, N Patrik; Vogelius, Ivan R.; Berthelsen, Anne K.; Specht, Lena; Petersen, Peter M.

    2015-05-01

    Purpose: Hodgkin lymphoma (HL) survivors have an increased risk of cardiovascular disease (CD), lung cancer, and breast cancer. We investigated the risk for the development of CD and secondary lung, breast, and thyroid cancer after radiation therapy (RT) delivered with deep inspiration breath-hold (DIBH) compared with free-breathing (FB) using 3-dimensional conformal RT (3DCRT) and intensity modulated RT (IMRT). The aim of this study was to determine which treatment modality best reduced the combined risk of life-threatening late effects in patients with mediastinal HL. Methods and Materials: Twenty-two patients with early-stage mediastinal HL were eligible for the study. Treatment plans were calculated with both 3DCRT and IMRT on both DIBH and FB planning computed tomographic scans. We reported the estimated dose to the heart, lung, female breasts, and thyroid and calculated the estimated life years lost attributable to CD and to lung, breast, and thyroid cancer. Results: DIBH lowered the estimated dose to heart and lung regardless of delivery technique (P<.001). There was no significant difference between IMRT-FB and 3DCRT-DIBH in mean heart dose, heart V20Gy, and lung V20Gy. The mean breast dose was increased with IMRT regardless of breathing technique. Life years lost was lowest with DIBH and highest with FB. Conclusions: In this cohort, 3DCRT-DIBH resulted in lower estimated doses and lower lifetime excess risks than did IMRT-FB. Combining IMRT and DIBH could be beneficial for a subgroup of patients.

  3. Mind-body relationships in elite apnea divers during breath holding: a study of autonomic responses to acute hypoxemia.

    PubMed

    Laurino, Marco; Menicucci, Danilo; Mastorci, Francesca; Allegrini, Paolo; Piarulli, Andrea; Scilingo, Enzo P; Bedini, Remo; Pingitore, Alessandro; Passera, Mirko; L'abbate, Antonio; Gemignani, Angelo

    2012-01-01

    The mental control of ventilation with all associated phenomena, from relaxation to modulation of emotions, from cardiovascular to metabolic adaptations, constitutes a psychophysiological condition characterizing voluntary breath-holding (BH). BH induces several autonomic responses, involving both autonomic cardiovascular and cutaneous pathways, whose characterization is the main aim of this study. Electrocardiogram and skin conductance (SC) recordings were collected from 14 elite divers during three conditions: free breathing (FB), normoxic phase of BH (NPBH) and hypoxic phase of BH (HPBH). Thus, we compared a set of features describing signal dynamics between the three experimental conditions: from heart rate variability (HRV) features (in time and frequency-domains and by using nonlinear methods) to rate and shape of spontaneous SC responses (SCRs). The main result of the study rises by applying a Factor Analysis to the subset of features significantly changed in the two BH phases. Indeed, the Factor Analysis allowed to uncover the structure of latent factors which modeled the autonomic response: a factor describing the autonomic balance (AB), one the information increase rate (IIR), and a latter the central nervous system driver (CNSD). The BH did not disrupt the FB factorial structure, and only few features moved among factors. Factor Analysis indicates that during BH (1) only the SC described the emotional output, (2) the sympathetic tone on heart did not change, (3) the dynamics of interbeats intervals showed an increase of long-range correlation that anticipates the HPBH, followed by a drop to a random behavior. In conclusion, data show that the autonomic control on heart rate and SC are differentially modulated during BH, which could be related to a more pronounced effect on emotional control induced by the mental training to BH. PMID:22461774

  4. Mechanical indentation improves cerebral blood oxygenation signal quality of functional near-infrared spectroscopy (fNIRS) during breath holding

    NASA Astrophysics Data System (ADS)

    Vogt, William C.; Romero, Edwin; LaConte, Stephen M.; Rylander, Christopher G.

    2013-03-01

    Functional near-infrared spectroscopy (fNIRS) is a well-known technique for non-invasively measuring cerebral blood oxygenation, and many studies have demonstrated that fNIRS signals can be related to cognitive function. However, the fNIRS signal is attenuated by the skin, while scalp blood content has been reported to influence cerebral oxygenation measurements. Mechanical indentation has been shown to increase light transmission through soft tissues by causing interstitial water and blood flow away from the compressed region. To study the effects of indentation on fNIRS, a commercial fNIRS system with 16 emitter/detector pairs was used to measure cerebral blood oxygenation at 2 Hz. This device used diffuse reflectance at 730 nm and 850 nm to calculate deoxy- and oxy-hemoglobin concentrations. A borosilicate glass hemisphere was epoxied over each sensor to function as both an indenter and a lens. After placing the indenter/sensor assembly on the forehead, a pair of plastic bands was placed on top of the fNIRS headband and strapped to the head to provide uniform pressure and tightened to approx. 15 N per strap. Cerebral blood oxygenation was recorded during a breath holding regime (15 second hold, 15 second rest, 6 cycles) in 4 human subjects both with and without the indenter array. Results showed that indentation increased raw signal intensity by 85 +/- 35%, and that indentation increased amplitude of hemoglobin changes during breath cycles by 313% +/- 105%. These results suggest that indentation improves sensing of cerebral blood oxygenation, and may potentially enable sensing of deeper brain tissues.

  5. Changes in Respiratory Parameters and Fin-Swimming Performance Following a 16-Week Training Period with Intermittent Breath Holding.

    PubMed

    Stavrou, Vasileios; Toubekis, Argyris G; Karetsi, Eleni

    2015-12-22

    The purpose of this study was to examine the effects of training with intermittent breath holding (IBH) on respiratory parameters, arterial oxygen saturation (SpO2) and performance. Twenty-eight fin-swimming athletes were randomly divided into two groups and followed the same training for 16 weeks. About 40% of the distance of each session was performed with self-selected breathing frequency (SBF group) or IBH (IBH group). Performance time of 50 and 400 m at maximum intensity was recorded and forced expired volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and SpO2 were measured before and after the 50 m test at baseline and post-training. Post-training, the respiratory parameters were increased in the IBH but remained unchanged in the SBF group (FEV1: 17 ±15% vs. -1 ±11%; FVC: 22 ±13% vs. 1 ±10%; PEF: 9 ±14% vs. -4 ±15%; p<0.05). Pre compared to post-training SpO2 was unchanged at baseline and decreased post-training following the 50 m test in both groups (p<0.05). The reduction was higher in the IBH compared to the SBF group (p<0.05). Performance in the 50 and 400 m tests improved in both groups, however, the improvement was greater in the IBH compared to the SBF group in both 50 and 400 m tests (p<0.05). The use of IBH is likely to enhance the load on the respiratory muscles, thus, contributing to improvement of the respiratory parameters. Decreased SpO2 after IBH is likely due to adaptation to hypoventilation. IBH favours performance improvement at 50 and 400 m fin-swimming. PMID:26839609

  6. Changes in Respiratory Parameters and Fin-Swimming Performance Following a 16-Week Training Period with Intermittent Breath Holding

    PubMed Central

    Stavrou, Vasileios; Toubekis, Argyris G.; Karetsi, Eleni

    2015-01-01

    The purpose of this study was to examine the effects of training with intermittent breath holding (IBH) on respiratory parameters, arterial oxygen saturation (SpO2) and performance. Twenty-eight fin-swimming athletes were randomly divided into two groups and followed the same training for 16 weeks. About 40% of the distance of each session was performed with self-selected breathing frequency (SBF group) or IBH (IBH group). Performance time of 50 and 400 m at maximum intensity was recorded and forced expired volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and SpO2 were measured before and after the 50 m test at baseline and post-training. Post-training, the respiratory parameters were increased in the IBH but remained unchanged in the SBF group (FEV1: 17 ±15% vs. −1 ±11%; FVC: 22 ±13% vs. 1 ±10%; PEF: 9 ±14% vs. −4 ±15%; p<0.05). Pre compared to post-training SpO2 was unchanged at baseline and decreased post-training following the 50 m test in both groups (p<0.05). The reduction was higher in the IBH compared to the SBF group (p<0.05). Performance in the 50 and 400 m tests improved in both groups, however, the improvement was greater in the IBH compared to the SBF group in both 50 and 400 m tests (p<0.05). The use of IBH is likely to enhance the load on the respiratory muscles, thus, contributing to improvement of the respiratory parameters. Decreased SpO2 after IBH is likely due to adaptation to hypoventilation. IBH favours performance improvement at 50 and 400 m fin-swimming. PMID:26839609

  7. Decompression sickness in breath-hold diving, and its probable connection to the growth and dissolution of small arterial gas emboli.

    PubMed

    Goldman, Saul; Solano-Altamirano, J M

    2015-04-01

    We solved the Laplace equation for the radius of an arterial gas embolism (AGE), during and after breath-hold diving. We used a simple three-region diffusion model for the AGE, and applied our results to two types of breath-hold dives: single, very deep competitive-level dives and repetitive shallower breath-hold dives similar to those carried out by indigenous commercial pearl divers in the South Pacific. Because of the effect of surface tension, AGEs tend to dissolve in arterial blood when arteries remote from supersaturated tissue. However if, before fully dissolving, they reach the capillary beds that perfuse the brain and the inner ear, they may become inflated with inert gas that is transferred into them from these contiguous temporarily supersaturated tissues. By using simple kinetic models of cerebral and inner ear tissue, the nitrogen tissue partial pressures during and after the dive(s) were determined. These were used to theoretically calculate AGE growth and dissolution curves for AGEs lodged in capillaries of the brain and inner ear. From these curves it was found that both cerebral and inner ear decompression sickness are expected to occur occasionally in single competitive-level dives. It was also determined from these curves that for the commercial repetitive dives considered, the duration of the surface interval (the time interval separating individual repetitive dives from one another) was a key determinant, as to whether inner ear and/or cerebral decompression sickness arose. Our predictions both for single competitive-level and repetitive commercial breath-hold diving were consistent with what is known about the incidence of cerebral and inner ear decompression sickness in these forms of diving. PMID:25598211

  8. Relationship between Class III malocclusion and hyoid bone displacement during swallowing: a cine-magnetic resonance imaging study

    PubMed Central

    Gokce, Hasan Suat; Gorgulu, Serkan; Karacay, Seniz; Akca, Eralp; Olmez, Huseyin

    2012-01-01

    Objective The displacement of the hyoid bone (HB) is a critical biomechanical component of the swallowing function. The aim of this study was to evaluate the swallowing-induced vertical and horizontal displacements of the HB in subjects with 2 different magnitudes of skeletal Class III malocclusion, by means of real-time, balanced turbo-field-echo (B-TFE) cine-magnetic resonance imaging. Methods The study population comprised 19 patients with mild skeletal Class III malocclusion, 16 with severe skeletal Class III malocclusion, and 20 with a skeletal Class I relationship. Before the commencement of the study, all subjects underwent cephalometric analysis to identify the nature of skeletal malformations. B-TFE images were obtained for the 4 consecutive stages of deglutition as each patient swallowed 10 mL of water, and the vertical and horizontal displacements of the HB were measured at each stage. Results At all stages of swallowing, the vertical position of the HB in the severe Class III malocclusion group was significantly lower than those in the mild Class III and Class I malocclusion groups. Similarly, the horizontal displacement of the HB was found to be significantly associated with the severity of malocclusion, i.e., the degree of Class III malocclusion, while the amount of anterior displacement of the HB decreased with an increase in the severity of the Class III deformity. Conclusions Our findings indicate the existence of a relationship between the magnitude of Class III malocclusion and HB displacement during swallowing. PMID:23112950

  9. Evaluation of template matching for tumor motion management with cine-MR images in lung cancer patients

    PubMed Central

    Shi, Xiutao; Diwanji, Tejan; Mooney, Karen E.; Lin, Jolinta; Feigenberg, Steven; D’Souza, Warren D.; Mistry, Nilesh N.

    2014-01-01

    Purpose: Accurate determination of tumor position is crucial for successful application of motion compensated radiotherapy in lung cancer patients. This study tested the performance of an automated template matching algorithm in tracking the tumor position on cine-MR images by examining the tracking error and further comparing the tracking error to the interoperator variability of three human reviewers. Methods: Cine-MR images of 12 lung cancer patients were analyzed. Tumor positions were determined both automatically with template matching and manually by a radiation oncologist and two additional reviewers trained by the radiation oncologist. Performance of the automated template matching was compared against the ground truth established by the radiation oncologist. Additionally, the tracking error of template matching, defined as the difference in the tumor positions determined with template matching and the ground truth, was investigated and compared to the interoperator variability for all patients in the anterior-posterior (AP) and superior-inferior (SI) directions, respectively. Results: The median tracking error for ten out of the 12 patients studied in both the AP and SI directions was less than 1 pixel (= 1.95 mm). Furthermore, the median tracking error for seven patients in the AP direction and nine patients in the SI direction was less than half a pixel (= 0.975 mm). The median tracking error was positively correlated with the tumor motion magnitude in both the AP (R = 0.55, p = 0.06) and SI (R = 0.67, p = 0.02) directions. Also, a strong correlation was observed between tracking error and interoperator variability (y = 0.26 + 1.25x, R = 0.84, p < 0.001) with the latter larger. Conclusions: Results from this study indicate that the performance of template matching is comparable with or better than that of manual tumor localization. This study serves as preliminary investigations towards developing online motion tracking techniques for hybrid MRI

  10. SU-E-T-361: Clinical Benefit of Automatic Beam Gating Mixed with Breath Hold in Radiation Therapy of Left Breast

    SciTech Connect

    Wu, J; Hill, G; Spiegel, J; Ye, J; Mehta, V

    2014-06-01

    Purpose: To investigate the clinical and dosimetric benefits of automatic gating of left breast mixed with breath-hold technique. Methods: Two Active Breathing Control systems, ABC2.0 and ABC3.0, were used during simulation and treatment delivery. The two systems are different such that ABC2.0 is a breath-hold system without beam control capability, while ABC3.0 has capability in both breath-hold and beam gating. At simulation, each patient was scanned twice: one with free breathing (FB) and one with breath hold through ABC. Treatment plan was generated on the CT with ABC. The same plan was also recalculated on the CT with FB. These two plans were compared to assess plan quality. For treatments with ABC2.0, beams with MU > 55 were manually split into multiple subfields. All subfields were identical and shared the total MU. For treatment with ABC3.0, beam splitting was unnecessary. Instead, treatment was delivered in gating mode mixed with breath-hold technique. Treatment delivery efficiency using the two systems was compared. Results: The prescribed dose was 50.4Gy at 1.8Gy/fraction. The maximum heart dose averaged over 10 patients was 46.0±2.5Gy and 24.5±12.2Gy for treatments with FB and with ABC respectively. The corresponding heart V10 was 13.2±3.6% and 1.0±1.6% respectively. The averaged MUs were 99.8±7.5 for LMT, 99.2±9.4 for LLT. For treatment with ABC2.0, normally the original beam was split into 2 subfields. The averaged total time to delivery all beams was 4.3±0.4min for treatments with ABC2.0 and 3.3±0.6min for treatments with ABC3.0 in gating mode. Conclusion: Treatment with ABC tremendously reduced heart dose. Compared to treatments with ABC2.0, gating with ABC3.0 reduced the total treatment time by 23%. Use of ABC3.0 improved the delivery efficiency, and eliminated the possibility of mistreatments. The latter may happen with ABC2.0 where beam is not terminated when breath signal falls outside of the treatment window.

  11. SU-C-210-04: Considerable Pancreatic Tumor Motion During Breath-Hold Measured Using Intratumoral Fiducials On Fluoroscopic Movies

    SciTech Connect

    Lens, E; Horst, A van der; Versteijne, E; Tienhoven, G van; Bel, A

    2015-06-15

    Purpose: Using a breath hold (BH) technique during radiotherapy of pancreatic tumors is expected to reduce intra-fractional motion. The aim of this study was to evaluate the tumor motion during BH. Methods: In this pilot study, we included 8 consecutive pancreatic cancer patients. All had 2– 4 intratumoral gold fiducials. Patients were asked to perform 3 consecutive 30-second end-inhale BHs on day 5, 10 and 15 of their three-week treatment. During BH, airflow through a mouthpiece was measured using a spirometer. Any inadvertent flow of air during BH was monitored for all patients. We measured tumor motion on lateral fluoroscopic movies (57 in total) made during BH. In each movie the fiducials as a group were tracked over time in superior-inferior (SI) and anterior-posterior (AP) direction using 2-D image correlation between consecutive frames. We determined for each patient the range of intra-BH motion over all movies; we also determined the absolute means and standard deviations (SDs) for the entire patient group. Additionally, we investigated the relation between inadvertent airflow during BH and the intra-BH motion. Results: We found intra-BH tumor motion of up to 12.5 mm (range, 1.0–12.5 mm) in SI direction and up to 8.0 mm (range, 1.0–8.0 mm) in AP direction. The absolute mean motion over the patient population was 4.7 (SD: 3.0) mm and 2.8 (SD: 1.2) mm in the SI and AP direction, respectively. Patients were able to perform stable consecutive BHs; during only 20% of the movies we found very small airflows (≤ 65 ml). These were mostly stepwise in nature and could not explain the continuous tumor motions we observed. Conclusion: We found substantial (up to 12.5 mm) pancreatic tumor motion during BHs. We found minimal inadvertent airflow, seen only during a minority of BHs, and this did not explain the obtained results. This work was supported by the foundation Bergh in het Zadel through the Dutch Cancer Society (KWF Kankerbestrijding) project No. UVA 2011-5271.

  12. Undersampled Cine 3D tagging for rapid assessment of cardiac motion

    PubMed Central

    2012-01-01

    Background CMR allows investigating cardiac contraction, rotation and torsion non-invasively by the use of tagging sequences. Three-dimensional tagging has been proposed to cover the whole-heart but data acquisition requires three consecutive breath holds and hence demands considerable patient cooperation. In this study we have implemented and studied k-t undersampled cine 3D tagging in conjunction with k-t PCA reconstruction to potentially permit for single breath-hold acquisitions. Methods The performance of undersampled cine 3D tagging was investigated using computer simulations and in-vivo measurements in 8 healthy subjects and 5 patients with myocardial infarction. Fully sampled data was obtained and compared to retrospectively and prospectively undersampled acquisitions. Fully sampled data was acquired in three consecutive breath holds. Prospectively undersampled data was obtained within a single breath hold. Based on harmonic phase (HARP) analysis, circumferential shortening, rotation and torsion were compared between fully sampled and undersampled data using Bland-Altman and linear regression analysis. Results In computer simulations, the error for circumferential shortening was 2.8 ± 2.3% and 2.7 ± 2.1% for undersampling rates of R = 3 and 4 respectively. Errors in ventricular rotation were 2.5 ± 1.9% and 3.0 ± 2.2% for R = 3 and 4. Comparison of results from fully sampled in-vivo data acquired with prospectively undersampled acquisitions showed a mean difference in circumferential shortening of −0.14 ± 5.18% and 0.71 ± 6.16% for R = 3 and 4. The mean differences in rotation were 0.44 ± 1.8° and 0.73 ± 1.67° for R = 3 and 4, respectively. In patients peak, circumferential shortening was significantly reduced (p < 0.002 for all patients) in regions with late gadolinium enhancement. Conclusion Undersampled cine 3D tagging enables significant reduction in scan time of whole-heart tagging and

  13. Automated classification of LV regional wall motion based on spatio-temporal profiles from cardiac cine magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Mantilla, Juan; Garreau, Mireille; Bellanger, Jean-Jacques; Paredes, José Luis

    2013-11-01

    Assessment of the cardiac Left Ventricle (LV) wall motion is generally based on visual inspection or quantitative analysis of 2D+t sequences acquired in short-axis cardiac cine-Magnetic Resonance Imaging (MRI). Most often, cardiac dynamic is globally analized from two particular phases of the cardiac cycle. In this paper, we propose an automated method to classify regional wall motion in LV function based on spatio-temporal pro les and Support Vector Machines (SVM). This approach allows to obtain a binary classi cation between normal and abnormal motion, without the need of pre-processing and by exploiting all the images of the cardiac cycle. In each short- axis MRI slice level (basal, median, and apical), the spatio-temporal pro les are extracted from the selection of a subset of diametrical lines crossing opposites LV segments. Initialized at end-diastole phase, the pro les are concatenated with their corresponding projections into the succesive temporal phases of the cardiac cycle. These pro les are associated to di erent types of information that derive from the image (gray levels), Fourier, Wavelet or Curvelet domains. The approach has been tested on a set of 14 abnormal and 6 healthy patients by using a leave-one-out cross validation and two kernel functions for SVM classi er. The best classi cation performance is yielded by using four-level db4 wavelet transform and SVM with a linear kernel. At each slice level the results provided a classi cation rate of 87.14% in apical level, 95.48% in median level and 93.65% in basal level.

  14. Monitoring ABC-assisted deep inspiration breath hold for left-sided breast radiotherapy with an optical tracking system

    SciTech Connect

    Mittauer, Kathryn E.; Deraniyagala, Rohan; Li, Jonathan G.; Lu, Bo; Liu, Chihray; Samant, Sanjiv S.; Lightsey, Judith L.; Yan, Guanghua

    2015-01-15

    Purpose: Recent knowledge on the effects of cardiac toxicity warrants greater precision for left-sided breast radiotherapy. Different breath-hold (BH) maneuvers (abdominal vs thoracic breathing) can lead to chest wall positional variations, even though the patient’s tidal volume remains consistent. This study aims to investigate the feasibility of using optical tracking for real-time quality control of active breathing coordinator (ABC)-assisted deep inspiration BH (DIBH). Methods: An in-house optical tracking system (OTS) was used to monitor ABC-assisted DIBH. The stability and localization accuracy of the OTS were assessed with a ball-bearing phantom. Seven patients with left-sided breast cancer were included. A free-breathing (FB) computed tomography (CT) scan and an ABC-assisted BH CT scan were acquired for each patient. The OTS tracked an infrared (IR) marker affixed over the patient’s xiphoid process to measure the positional variation of each individual BH. Using the BH within which the CT scan was performed as the reference, the authors quantified intra- and interfraction BH variations for each patient. To estimate the dosimetric impact of BH variations, the authors studied the positional correlation between the marker and the left breast using the FB CT and BH CT scans. The positional variations of 860 BHs as measured by the OTS were retrospectively incorporated into the original treatment plans to evaluate their dosimetric impact on breast and cardiac organs [heart and left anterior descending (LAD) artery]. Results: The stability and localization accuracy of the OTS was within 0.2 mm along each direction. The mean intrafraction variation among treatment BHs was less than 2.8 mm in all directions. Up to 12.6 mm anteroposterior undershoot, where the patient’s chest wall displacement of a BH is less than that of a reference BH, was observed with averages of 4.4, 3.6, and 0.1 mm in the anteroposterior, craniocaudal, and mediolateral directions

  15. SU-C-BRF-01: Correlation of DIBH Breath Hold Amplitude with Dosimetric Sparing of Heart and Left Anterior Descending Artery in Left Breast Radiotherapy

    SciTech Connect

    Kim, Taeho; Reardon, Kelli; Sukovich, Kaitlyn; Crandley, Edwin; Read, Paul; Krishni, Wijesooriya

    2014-06-15

    Purpose: A 7.4% increase in major coronary events per 1 Gy increase in mean heart dose has been reported from the population-based analysis of radiation-induced cardiac toxicity following treatment of left sided breast cancer. Deep inhalation breath-hold (DIBH) is clinically utilized to reduce radiation dose to heart and left anterior descending artery (LAD). We investigated the correlation of dose sparing in heart and LAD with internal DIBH amplitude to develop a quantitative predictive model for expected dose to heart and LAD based on internal breath hold amplitude. Methods: A treatment planning study (Prescription Dose = 50 Gy) was performed on 50 left breast cancer patients underwent DIBH whole breast radiotherapy. Two CT datasets, free breathing (FB) and DIBH, were utilized for treatment planning and for determination of the internal anatomy DIBH amplitude (difference between sternum position at FB and DIBH). The heart and LAD dose between FB and DIBH plans was compared and dose to the heart and LAD as a function of breath hold amplitude was determined. Results: Average DIBH amplitude using internal anatomy was 13.9±4.2 mm. The DIBH amplitude-mean dose reduction correlation is 20%/5mm (0.3 Gy/5mm) for the heart and 18%/5mm (1.1 Gy/5mm) for LAD. The correlation with max dose reduction is 12%/5mm (3.8 Gy/5mm) for the heart and 16%/5mm (3.2 Gy/5mm) for LAD. We found that average dose reductions to LAD from 6.0±6.5 Gy to 2.0±1.6 Gy with DIBH (4.0 Gy reduction: -67%, p < 0.001) and average dose reduction to the heart from 1.3±0.7 Gy to 0.7±0.2 Gy with DIBH (0.6 Gy reduction: -46%, p < 0.001). That suggests using DIBH may reduce the risk of the major coronary event for left sided breast cancer patients. Conclusion: The correlation between breath hold amplitude and dosimetric sparing suggests that dose sparing linearly increases with internal DIBH amplitude.

  16. How to perform and interpret cine MR enterography.

    PubMed

    Wnorowski, Amelia M; Guglielmo, Flavius F; Mitchell, Donald G

    2015-11-01

    Magnetic resonance (MR) enterography has become a fundamental tool for small bowel evaluation. Multiphasic cine imaging is a useful component of MR enterography evaluation because it provides functional information about bowel motility. Cine MR enterography can be used to evaluate for strictures and adhesions. Bowel motility evaluation has been shown to increase pathologic lesion detection in Crohn's disease and has been incorporated into disease activity scoring systems. Currently, cine MR enterography remains underutilized. The purpose of this article is to outline how to perform and interpret cine MR enterography. The authors describe how to perform a multiphasic balanced steady state free precession sequence using different MR systems and give practical advice on how to display and interpret the cine sequence. Sample cases illustrate how the cine sequence complements standard MR enterography evaluation with T2 -weighted, contrast-enhanced T1 -weighted, and diffusion-weighted imaging. PMID:26179244

  17. Influence of the short-axis cine acquisition protocol on the cardiac function evaluation: A reproducibility study

    PubMed Central

    Marchesseau, Stephanie; Ho, Jamie X.M.; Totman, John J.

    2016-01-01

    Purpose To define the optimal cardiac short-axis cine acquisition protocol for the assessment of the left and rightventricular functions. Materials and methods 20 volunteers were recruited and breath-hold CINE images were acquired on a Siemens Prisma 3T MRI. Four short-axis acquisition planes were defined from the 4-chamber view. AV Junctions: short-axis slices parallel to the plane that cuts through the external right and left atrioventricular junctions. Left AV Junctions: short-axis slices parallel to the plane that cuts through both left atrioventricular junctions. Septum: short-axis slices perpendicular to the septum with one cutting through the septum junction. LongAxis: short-axis slices perpendicular to the long axis with one cutting through the septum junction. Intra and inter reproducibility was assessed using Bland-Altman coefficient of variation (CV) and Lin’s concordance correlation coefficient (CCC). The influence of the protocol on the ejection fraction (EF) and stroke volume (SV) was quantified statistically using pair-wise CV and Pearson’s correlation coefficient R2. Results All protocols led to high reproducibility for the LV EF (mean intra CV = 3.83%, mean inter CV = 4.81%, lowest CV = 4.20% (AV junctions) and highest CV = 5.24% (Left AV Junctions)). Reproducibility of the RV measurements was lower (mean intra CV = 7.84%, mean inter CV = 9.17%). Septum protocol led to significantly lower variability compared to the other 3 protocols for RV EF (CV = 7.62% (Septum), CV = 8.42% (Long Axis), CV = 9.54% (Left AV Junctions) and CV = 11.08% (AV Junctions) with Lin’s CCC varying from 0.4 (AV Junctions) to 0.69 (Septum) for inter-observer reproducibility). No differences in group average for clinical parameters was found for both LV and RV clinical measurements. However, patient-specific RV EF evaluation is dependent on the chosen protocol (CV = 9.95%, R2 = 0.52). Conclusion Based on the results of the study cine mode short

  18. Accuracy of Routine Treatment Planning 4-Dimensional and Deep-Inspiration Breath-Hold Computed Tomography Delineation of the Left Anterior Descending Artery in Radiation Therapy

    SciTech Connect

    White, Benjamin M.; Vennarini, Sabina; Lin, Lilie; Freedman, Gary; Santhanam, Anand; Low, Daniel A.; Both, Stefan

    2015-03-15

    Purpose: To assess the feasibility of radiation therapy treatment planning 4-dimensional computed tomography (4DCT) and deep-inspiration breath-hold (DIBH) CT to accurately contour the left anterior descending artery (LAD), a primary indicator of radiation-induced cardiac toxicity for patients undergoing radiation therapy. Methods and Materials: Ten subjects were prospectively imaged with a cardiac-gated MRI protocol to determine cardiac motion effects, including the displacement of a region of interest comprising the LAD. A series of planar views were obtained and resampled to create a 3-dimensional (3D) volume. A 3D optical flow deformable image registration algorithm determined tissue displacement during the cardiac cycle. The measured motion was then used as a spatial boundary to characterize motion blurring of the radiologist-delineated LAD structure for a cohort of 10 consecutive patients enrolled prospectively on a breast study including 4DCT and DIBH scans. Coronary motion–induced blurring artifacts were quantified by applying an unsharp filter to accentuate the LAD structure despite the presence of motion blurring. The 4DCT maximum inhalation and exhalation respiratory phases were coregistered to determine the LAD displacement during tidal respiration, as visualized in 4DCT. Results: The average 90th percentile heart motion for the region of interest was 0.7 ± 0.1 mm (left–right [LR]), 1.3 ± 0.6 mm (superior–inferior [SI]), and 0.6 ± 0.2 mm (anterior–posterior [AP]) in the cardiac-gated MRI cohort. The average relative increase in the number of voxels comprising the LAD contour was 69.4% ± 4.5% for the DIBH. The LAD volume overestimation had the dosimetric impact of decreasing the reported mean LAD dose by 23% ± 9% on average in the DIBH. During tidal respiration the average relative LAD contour increase was 69.3% ± 5.9% and 67.9% ± 4.6% for inhalation and exhalation respiratory phases, respectively. The average 90th

  19. Motion management within two respiratory-gating windows: feasibility study of dual quasi-breath-hold technique in gated medical procedures

    NASA Astrophysics Data System (ADS)

    Kim, Taeho; Kim, Siyong; Park, Yang-Kyun; Youn, Kaylin K.; Keall, Paul; Lee, Rena

    2014-11-01

    A dual quasi-breath-hold (DQBH) technique is proposed for respiratory motion management (a hybrid technique combining breathing-guidance with breath-hold task in the middle). The aim of this study is to test a hypothesis that the DQBH biofeedback system improves both the capability of motion management and delivery efficiency. Fifteen healthy human subjects were recruited for two respiratory motion measurements (free breathing and DQBH biofeedback breathing for 15 min). In this study, the DQBH biofeedback system utilized the abdominal position obtained using an real-time position management (RPM) system (Varian Medical Systems, Palo Alto, USA) to audio-visually guide a human subject for 4 s breath-hold at EOI and 90% EOE (EOE90%) to improve delivery efficiency. We investigated the residual respiratory motion and the delivery efficiency (duty-cycle) of abdominal displacement within the gating window. The improvement of the abdominal motion reproducibility was evaluated in terms of cycle-to-cycle displacement variability, respiratory period and baseline drift. The DQBH biofeedback system improved the abdominal motion management capability compared to that with free breathing. With a phase based gating (mean ± std: 55  ±  5%), the averaged root mean square error (RMSE) of the abdominal displacement in the dual-gating windows decreased from 2.26 mm of free breathing to 1.16 mm of DQBH biofeedback (p-value = 0.007). The averaged RMSE of abdominal displacement over the entire respiratory cycles reduced from 2.23 mm of free breathing to 1.39 mm of DQBH biofeedback breathing in the dual-gating windows (p-value = 0.028). The averaged baseline drift dropped from 0.9 mm min-1 with free breathing to 0.09 mm min-1 with DQBH biofeedback (p-value = 0.048). The averaged duty-cycle with an 1 mm width of displacement bound increased from 15% of free breathing to 26% of DQBH biofeedback (p-value = 0.003). The study demonstrated that the DQBH biofeedback

  20. Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers

    PubMed Central

    Winklewski, Pawel J.; Barak, Otto; Madden, Dennis; Gruszecka, Agnieszka; Gruszecki, Marcin; Guminski, Wojciech; Kot, Jacek; Frydrychowski, Andrzej F.; Drvis, Ivan; Dujic, Zeljko

    2015-01-01

    Purpose The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). Methods The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Results Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Conclusions Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and

  1. Automatic generation of endocardial surface meshes with 1-to-1 correspondence from cine-MR images

    NASA Astrophysics Data System (ADS)

    Su, Yi; Teo, S.-K.; Lim, C. W.; Zhong, L.; Tan, R. S.

    2015-03-01

    In this work, we develop an automatic method to generate a set of 4D 1-to-1 corresponding surface meshes of the left ventricle (LV) endocardial surface which are motion registered over the whole cardiac cycle. These 4D meshes have 1- to-1 point correspondence over the entire set, and is suitable for advanced computational processing, such as shape analysis, motion analysis and finite element modelling. The inputs to the method are the set of 3D LV endocardial surface meshes of the different frames/phases of the cardiac cycle. Each of these meshes is reconstructed independently from border-delineated MR images and they have no correspondence in terms of number of vertices/points and mesh connectivity. To generate point correspondence, the first frame of the LV mesh model is used as a template to be matched to the shape of the meshes in the subsequent phases. There are two stages in the mesh correspondence process: (1) a coarse matching phase, and (2) a fine matching phase. In the coarse matching phase, an initial rough matching between the template and the target is achieved using a radial basis function (RBF) morphing process. The feature points on the template and target meshes are automatically identified using a 16-segment nomenclature of the LV. In the fine matching phase, a progressive mesh projection process is used to conform the rough estimate to fit the exact shape of the target. In addition, an optimization-based smoothing process is used to achieve superior mesh quality and continuous point motion.

  2. Differentiation between Focal Malignant Marrow-Replacing Lesions and Benign Red Marrow Deposition of the Spine with T2*-Corrected Fat-Signal Fraction Map Using a Three-Echo Volume Interpolated Breath-Hold Gradient Echo Dixon Sequence

    PubMed Central

    Kim, Yong Pyo; Kannengiesser, Stephan; Paek, Mun-Young; Chung, Tae-Sub; Yoo, Yeon Hwa; Yoon, Choon-Sik; Song, Ho-Taek; Lee, Young Han; Suh, Jin-Suck

    2014-01-01

    Objective To assess the feasibility of T2*-corrected fat-signal fraction (FF) map by using the three-echo volume interpolated breath-hold gradient echo (VIBE) Dixon sequence to differentiate between malignant marrow-replacing lesions and benign red marrow deposition of vertebrae. Materials and Methods We assessed 32 lesions from 32 patients who underwent magnetic resonance imaging after being referred for assessment of a known or possible vertebral marrow abnormality. The lesions were divided into 21 malignant marrow-replacing lesions and 11 benign red marrow depositions. Three sequences for the parameter measurements were obtained by using a 1.5-T MR imaging scanner as follows: three-echo VIBE Dixon sequence for FF; conventional T1-weighted imaging for the lesion-disc ratio (LDR); pre- and post-gadolinium enhanced fat-suppressed T1-weighted images for the contrast-enhancement ratio (CER). A region of interest was drawn for each lesion for parameter measurements. The areas under the curve (AUC) of the parameters and their sensitivities and specificities at the most ideal cutoff values from receiver operating characteristic curve analysis were obtained. AUC, sensitivity, and specificity were respectively compared between FF and CER. Results The AUCs of FF, LDR, and CER were 0.96, 0.80, and 0.72, respectively. In the comparison of diagnostic performance between the FF and CER, the FF showed a significantly larger AUC as compared to the CER (p = 0.030), although the difference of sensitivity (p = 0.157) and specificity (p = 0.157) were not significant. Conclusion Fat-signal fraction measurement using T2*-corrected three-echo VIBE Dixon sequence is feasible and has a more accurate diagnostic performance, than the CER, in distinguishing benign red marrow deposition from malignant bone marrow-replacing lesions. PMID:25469090

  3. Whole left ventricular functional assessment from two minutes free breathing multi-slice CINE acquisition

    NASA Astrophysics Data System (ADS)

    Usman, M.; Atkinson, D.; Heathfield, E.; Greil, G.; Schaeffter, T.; Prieto, C.

    2015-04-01

    Two major challenges in cardiovascular MRI are long scan times due to slow MR acquisition and motion artefacts due to respiratory motion. Recently, a Motion Corrected-Compressed Sensing (MC-CS) technique has been proposed for free breathing 2D dynamic cardiac MRI that addresses these challenges by simultaneously accelerating MR acquisition and correcting for any arbitrary motion in a compressed sensing reconstruction. In this work, the MC-CS framework is combined with parallel imaging for further acceleration, and is termed Motion Corrected Sparse SENSE (MC-SS). Validation of the MC-SS framework is demonstrated in eight volunteers and three patients for left ventricular functional assessment and results are compared with the breath-hold acquisitions as reference. A non-significant difference (P > 0.05) was observed in the volumetric functional measurements (end diastolic volume, end systolic volume, ejection fraction) and myocardial border sharpness values obtained with the proposed and gold standard methods. The proposed method achieves whole heart multi-slice coverage in 2 min under free breathing acquisition eliminating the time needed between breath-holds for instructions and recovery. This results in two-fold speed up of the total acquisition time in comparison to the breath-hold acquisition.

  4. Left ventricular strain and its pattern estimated from cine CMR and validation with DENSE

    NASA Astrophysics Data System (ADS)

    Gao, Hao; Allan, Andrew; McComb, Christie; Luo, Xiaoyu; Berry, Colin

    2014-07-01

    Measurement of local strain provides insight into the biomechanical significance of viable myocardium. We attempted to estimate myocardial strain from cine cardiovascular magnetic resonance (CMR) images by using a b-spline deformable image registration method. Three healthy volunteers and 41 patients with either recent or chronic myocardial infarction (MI) were studied at 1.5 Tesla with both cine and DENSE CMR. Regional circumferential and radial left ventricular strains were estimated from cine and DENSE acquisitions. In all healthy volunteers, there was no difference for peak circumferential strain (- 0.18 ± 0.04 versus - 0.18 ± 0.03, p = 0.76) between cine and DENSE CMR, however peak radial strain was overestimated from cine (0.84 ± 0.37 versus 0.49 ± 0.2, p < 0.01). In the patient study, the peak strain patterns predicted by cine were similar to the patterns from DENSE, including the strain evolution related to recovery time and strain patterns related to MI scar extent. Furthermore, cine-derived strain disclosed different strain patterns in MI and non-MI regions, and regions with transmural and non-transmural MI as DENSE. Although there were large variations with radial strain measurements from cine CMR images, useful circumferential strain information can be obtained from routine clinical CMR imaging. Cine strain analysis has potential to improve the diagnostic yield from routine CMR imaging in clinical practice.

  5. Deep inspiration breath-hold technique for left-sided breast cancer: An analysis of predictors for organ-at-risk sparing

    SciTech Connect

    Register, Steven; Takita, Cristiane; Reis, Isildinha; Zhao, Wei; Amestoy, William; Wright, Jean

    2015-04-01

    To identify anatomic and treatment characteristics that correlate with organ-at-risk (OAR) sparing with deep inspiration breath-hold (DIBH) technique to guide patient selection for this technique. Anatomic and treatment characteristics and radiation doses to OARs were compared between free-breathing and DIBH plans. Linear regression analysis was used to identify factors independently predicting for cardiac sparing. We identified 64 patients: 44 with intact breast and 20 postmastectomy. For changes measured directly on treatment planning scans, DIBH plans decreased heart-chest wall length (6.5 vs 5.0 cm, p < 0.001), and increased lung volume (1074.4 vs 1881.3 cm{sup 3}, p < 0.001), and for changes measured after fields are set, they decreased maximum heart depth (1.1 vs 0.3 cm, p < 0.001) and heart volume in field (HVIF) (9.1 vs 0.9 cm{sup 3}, p < 0.001). DIBH reduced the mean heart dose (3.4 vs 1.8 Gy, p < 0.001) and lung V{sub 20} (19.6% vs 15.3%, p < 0.001). Regression analysis found that only change in HVIF independently predicted for cardiac sparing. We identified patients in the bottom quartile of the dosimetric benefits seen with DIBH and categorized the cause of this “minimal benefit.” Overall, 29% of patients satisfied these criteria for minimal benefit with DIBH and the most common cause was favorable baseline anatomy. Only the reduction in HVIF predicted for reductions in mean heart dose; no specific anatomic surrogate for the dosimetric benefits of DIBH technique could be identified. Most patients have significant dosimetric benefit with DIBH, and this technique should be planned and evaluated for all patients receiving left-sided breast/chest wall radiation.

  6. A comparative analysis of 3D conformal deep inspiratory–breath hold and free-breathing intensity-modulated radiation therapy for left-sided breast cancer

    SciTech Connect

    Reardon, Kelli A.; Read, Paul W.; Morris, Monica M.; Reardon, Michael A.; Geesey, Constance; Wijesooriya, Krishni

    2013-07-01

    Patients undergoing radiation for left-sided breast cancer have increased rates of coronary artery disease. Free-breathing intensity-modulated radiation therapy (FB-IMRT) and 3-dimensional conformal deep inspiratory–breath hold (3D-DIBH) reduce cardiac irradiation. The purpose of this study is to compare the dose to organs at risk in FB-IMRT vs 3D-DIBH for patients with left-sided breast cancer. Ten patients with left-sided breast cancer had 2 computed tomography scans: free breathing and voluntary DIBH. Optimization of the IMRT plan was performed on the free-breathing scan using 6 noncoplanar tangential beams. The 3D-DIBH plan was optimized on the DIBH scan and used standard tangents. Mean volumes of the heart, the left anterior descending coronary artery (LAD), the total lung, and the right breast receiving 5% to 95% (5% increments) of the prescription dose were calculated. Mean volumes of the heart and the LAD were lower (p<0.05) in 3D-DIBH for volumes receiving 5% to 80% of the prescription dose for the heart and 5% for the LAD. Mean dose to the LAD and heart were lower in 3D-DIBH (p≤0.01). Mean volumes of the total lung were lower in FB-IMRT for dose levels 20% to 75% (p<0.05), but mean dose was not different. Mean volumes of the right breast were not different for any dose; however, mean dose was lower for 3D-DIBH (p = 0.04). 3D-DIBH is an alternative approach to FB-IMRT that provides a clinically equivalent treatment for patients with left-sided breast cancer while sparing organs at risk with increased ease of implementation.

  7. Reproducibility of The Abdominal and Chest Wall Position by Voluntary Breath-Hold Technique Using a Laser-Based Monitoring and Visual Feedback System

    SciTech Connect

    Nakamura, Katsumasa . E-mail: nakam@radiol.med.kyushu-u.ac.jp; Shioyama, Yoshiyuki; Nomoto, Satoru; Ohga, Saiji; Toba, Takashi; Yoshitake, Tadamasa; Anai, Shigeo; Terashima, Hiromi; Honda, Hiroshi

    2007-05-01

    Purpose: The voluntary breath-hold (BH) technique is a simple method to control the respiration-related motion of a tumor during irradiation. However, the abdominal and chest wall position may not be accurately reproduced using the BH technique. The purpose of this study was to examine whether visual feedback can reduce the fluctuation in wall motion during BH using a new respiratory monitoring device. Methods and Materials: We developed a laser-based BH monitoring and visual feedback system. For this study, five healthy volunteers were enrolled. The volunteers, practicing abdominal breathing, performed shallow end-expiration BH (SEBH), shallow end-inspiration BH (SIBH), and deep end-inspiration BH (DIBH) with or without visual feedback. The abdominal and chest wall positions were measured at 80-ms intervals during BHs. Results: The fluctuation in the chest wall position was smaller than that of the abdominal wall position. The reproducibility of the wall position was improved by visual feedback. With a monitoring device, visual feedback reduced the mean deviation of the abdominal wall from 2.1 {+-} 1.3 mm to 1.5 {+-} 0.5 mm, 2.5 {+-} 1.9 mm to 1.1 {+-} 0.4 mm, and 6.6 {+-} 2.4 mm to 2.6 {+-} 1.4 mm in SEBH, SIBH, and DIBH, respectively. Conclusions: Volunteers can perform the BH maneuver in a highly reproducible fashion when informed about the position of the wall, although in the case of DIBH, the deviation in the wall position remained substantial.

  8. Dosimetric Benefits of Intensity-Modulated Radiotherapy Combined With the Deep-Inspiration Breath-Hold Technique in Patients With Mediastinal Hodgkin's Lymphoma

    SciTech Connect

    Paumier, Amaury; Ghalibafian, Mithra; Gilmore, Jennifer; Beaudre, Anne; Blanchard, Pierre; El Nemr, Mohammed; Azoury, Farez; Al Hamokles, Hweej; Lefkopoulos, Dimitri; Girinsky, Theodore

    2012-03-15

    Purpose: To assess the additional benefits of using the deep-inspiration breath-hold (DIBH) technique with intensity-modulated radiotherapy (IMRT) in terms of the protection of organs at risk for patients with mediastinal Hodgkin's disease. Methods and Materials: Patients with early-stage Hodgkin's lymphoma with mediastinal involvement were entered into the study. Two simulation computed tomography scans were performed for each patient: one using the free-breathing (FB) technique and the other using the DIBH technique with a dedicated spirometer. The clinical target volume, planning target volume (PTV), and organs at risk were determined on both computed tomography scans according to the guidelines of the European Organization for Research and Treatment of Cancer. In both cases, 30 Gy in 15 fractions was prescribed. The dosimetric parameters retrieved for the statistical analysis were PTV coverage, mean heart dose, mean coronary artery dose, mean lung dose, and lung V20. Results: There were no significant differences in PTV coverage between the two techniques (FB vs. DIBH). The mean doses delivered to the coronary arteries, heart, and lungs were significantly reduced by 15% to 20% using DIBH compared with FB, and the lung V20 was reduced by almost one third. The dose reduction to organs at risk was greater for masses in the upper part of the mediastinum. IMRT with DIBH was partially implemented in 1 patient. This combination will be extended to other patients in the near future. Conclusions: Radiation exposure of the coronary arteries, heart, and lungs in patients with mediastinal Hodgkin's lymphoma was greatly reduced using DIBH with IMRT. The greatest benefit was obtained for tumors in the upper part of the mediastinum. The possibility of a wider use in clinical practice is currently under investigation in our department.

  9. Rate of disappearance of labeled carbon dioxide from the lungs of humans during breath holding: a method for studying the dynamics of pulmonary CO2 exchange

    PubMed Central

    Hyde, Richard W.; Puy, Ricardo J. M.; Raub, William F.; Forster, Robert E.

    1968-01-01

    The dynamics of CO2 exchange in the lungs of man was studied by observing the rate of disappearance of a stable isotope of CO2 (13CO2) from the alveolar gas during breath holding. Over 50% of the inspired isotope disappeared within the first 3 sec followed by a moderately rapid logarithmic decline in which one-half of the remaining 13CO2 disappeared every 10 sec. The large initial disappearance of 13CO2 indicated that alveolar 13CO2 equilibrated in less than 3 sec with the CO2 stored in the pulmonary tissues and capillary blood. The volume of CO2 in the pulmonary tissues calculated from this initial disappearance was 200 ml or 0.33 ml of CO2 per milliliter of pulmonary tissue volume. The alveolar to end-capillary gradient for 13CO2 was calculated by comparing the simultaneous disappearance rates of 13CO2 and acetylene. At rest and during exercise this gradient for 13CO2 was either very small or not discernible, and diffusing capacity for CO2 (DLCO2) exceeded 200 ml/(min × mm Hg). After the administration of a carbonic anhydrase inhibitor the rate of disappearance of 13CO2 decreased markedly. DLCO2 fell to 42 ml/(min × mm Hg) and at least 70% of the exchange of 13CO2 with the CO2 stores in the pulmonary tissues and blood was blocked by the inhibitor. These changes were attributed to impairment of exchange of 13CO2 with the bicarbonate in the pulmonary tissues and blood. The pH of the pulmonary tissues (Vtis) was determined by a method based on the premise that the CO2 space in the pulmonary tissues blocked by the inhibitor represented total bicarbonate content. At an alveolar PCO2 of 40 mm Hg pH of Vtis equalled 6.97 ± 0.09. PMID:5658586

  10. SU-E-J-32: Calypso(R) and Laser-Based Localization Systems Comparison for Left-Sided Breast Cancer Patients Using Deep Inspiration Breath Hold

    SciTech Connect

    Robertson, S; Kaurin, D; Sweeney, L; Kim, J; Fang, L; Tran, A; Holloway, K

    2014-06-01

    Purpose: Our institution uses a manual laser-based system for primary localization and verification during radiation treatment of left-sided breast cancer patients using deep inspiration breath hold (DIBH). This primary system was compared with sternum-placed Calypso(R) beacons (Varian Medical Systems, CA). Only intact breast patients are considered for this analysis. Methods: During computed tomography (CT) simulation, patients have BB and Calypso(R) surface beacons positioned sternally and marked for free-breathing and DIBH CTs. During dosimetry planning, BB longitudinal displacement between free breathing and DIBH CT determines laser mark (BH mark) location. Calypso(R) beacon locations from the DIBH CT are entered at the Tracking Station. During Linac simulation and treatment, patients inhale until the cross-hair and/or lasers coincide with the BH Mark, which can be seen using our high quality cameras (Pelco, CA). Daily Calypso(R) displacement values (difference from the DIBH-CT-based plan) are recorded.The displacement mean and standard deviation was calculated for each patient (77 patients, 1845 sessions). An aggregate mean and standard deviation was calculated weighted by the number of patient fractions.Some patients were shifted based on MV ports. A second data set was calculated with Calypso(R) values corrected by these shifts. Results: Mean displacement values indicate agreement within 1±3mm, with improvement for shifted data (Table). Conclusion: Both unshifted and shifted data sets show the Calypso(R) system coincides with the laser system within 1±3mm, demonstrating either localization/verification system will Resultin similar clinical outcomes. Displacement value uncertainty unilaterally reduces when shifts are taken into account.

  11. Purine metabolism in response to hypoxic conditions associated with breath-hold diving and exercise in erythrocytes and plasma from bottlenose dolphins (Tursiops truncatus).

    PubMed

    del Castillo Velasco-Martínez, Iris; Hernández-Camacho, Claudia J; Méndez-Rodríguez, Lía C; Zenteno-Savín, Tania

    2016-01-01

    In mammalian tissues under hypoxic conditions, ATP degradation results in accumulation of purine metabolites. During exercise, muscle energetic demand increases and oxygen consumption can exceed its supply. During breath-hold diving, oxygen supply is reduced and, although oxygen utilization is regulated by bradycardia (low heart rate) and peripheral vasoconstriction, tissues with low blood flow (ischemia) may become hypoxic. The goal of this study was to evaluate potential differences in the circulating levels of purine metabolism components between diving and exercise in bottlenose dolphins (Tursiops truncatus). Blood samples were taken from captive dolphins following a swimming routine (n=8) and after a 2min dive (n=8). Activity of enzymes involved in purine metabolism (hypoxanthine guanine phosphoribosyl transferase (HGPRT), inosine monophosphate deshydrogenase (IMPDH), xanthine oxidase (XO), purine nucleoside phosphorylase (PNP)), and purine metabolite (hypoxanthine (HX), xanthine (X), uric acid (UA), inosine monophosphate (IMP), inosine, nicotinamide adenine dinucleotide (NAD(+)), adenosine, adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, guanosine diphosphate (GDP), guanosine triphosphate (GTP)) concentrations were quantified in erythrocyte and plasma samples. Enzymatic activity and purine metabolite concentrations involved in purine synthesis and degradation, were not significantly different between diving and exercise. Plasma adenosine concentration was higher after diving than exercise (p=0.03); this may be related to dive-induced ischemia. In erythrocytes, HGPRT activity was higher after diving than exercise (p=0.007), suggesting an increased capacity for purine recycling and ATP synthesis from IMP in ischemic tissues of bottlenose dolphins during diving. Purine recycling and physiological adaptations may maintain the ATP concentrations in bottlenose dolphins after diving and exercise. PMID:26506131

  12. Radiation-induced second malignancies after involved-node radiotherapy with deep-inspiration breath-hold technique for early stage Hodgkin Lymphoma: a dosimetric study

    PubMed Central

    2014-01-01

    Background To estimate the risk of radiation induced second cancers after radiotherapy using deep-inspiration breath-hold (DI) technique with three-dimensional conformal (3DCRT) and volumetric arc therapy (VMAT) for patients with Hodgkin’s lymphoma (HL). Methods Early-stage HL with mediastinal and supraclavicular involvement was studied using an Alderson phantom. A whole body CT was performed and all tissues were delineated. The clinical target volumes and planning target volumes (PTV) were determined according to the German Hodgkin study group guidelines. Free-breathing (FB) technique and DI technique were simulated by different safety margins for the PTV definition. In both cases, 30 Gy in 15 fractions was prescribed. Second cancer risk was estimated for various tissues with a second cancer model including fractionation. Results When compared with FB-3DCRT, estimated relative life time attributable risk (LAR) of cancer induction after DI-3DCRT was 0.86, 0.76, 0.94 and 0.92 for breast, lung, esophagus and stomach, respectively. With DI-VMAT, the corresponding values were 2.05, 1.29, 1.01, 0.93, respectively. For breast cancer, the LAR observed with DI-VMAT was not substantially distinguishable from the LAR computed for mantle RT with an administered dose of 40 Gy. Conclusions This study suggests that DI may reduce the LAR of secondary cancers of all OARs and may be a valuable technique when using 3DCRT. Conversely, VMAT may increase substantially the LAR and should be cautiously implemented in clinical practice. PMID:24548307

  13. Recent experience with design and manufacture of cine lenses

    NASA Astrophysics Data System (ADS)

    Thorpe, Michael D.; Dalzell, Kristen E.

    2015-09-01

    Modern cine lenses require a high degree of aberration correction over a large and ever expanding image size. At low to medium volume production levels, these highly corrected designs also require a workable tolerance set and compensation scheme for successful manufacture. In this paper we discuss the design and manufacture of cine lenses with reference to current designs both internal and in the patent literature and some experience in design, tolerancing and manufacturing these lenses in medium volume production.

  14. Digital retrospective motion-mode display and processing of electron beam cine-computed tomography and other cross-sectional cardiac imaging techniques

    NASA Astrophysics Data System (ADS)

    Reed, Judd E.; Rumberger, John A.; Buithieu, Jean; Behrenbeck, Thomas; Breen, Jerome F.; Sheedy, Patrick F., II

    1995-05-01

    displays give the operator valuable feedback pertaining to the contiguity of the extracted surfaces. As with M-Mode echocardiography, the velocity of moving structures can be easily visualized and measured. However, many views inaccessible to standard transthoracic echocardiography are easily generated. These features have augmented the interpretability of cine electron beam computed tomography and have prompted the recent cloning of this system into an 'omni-directional M-Mode display' system for use in digital post-processing of echocardiographic parasternal short axis tomograms. This enhances the functional assessment in orthogonal views of the left ventricle, accounting for shape changes particularly in the asymmetric post-infarction ventricle. Conclusions: A new tool has been developed for analysis and visualization of cine electron beam computed tomography. It has been found to be very useful in verifying the consistency of myocardial surface definition with a semi-automated segmentation tool. By drawing on M-Mode echocardiography experience, electron beam tomography's interpretability has been enhanced. Use of this feature, in conjunction with the existing image processing tools, will enhance the presentations of data on regional systolic and diastolic functions to clinicians in a format that is familiar to most cardiologists. Additionally, this tool reinforces the advantages of electron beam tomography as a single imaging modality for the assessment of left and right ventricular size, shape, and regional functions.

  15. Obstructive sleep apnea screening by NIRS imaging

    NASA Astrophysics Data System (ADS)

    Kashefi, Feraydune; Watenpaugh, Donald E.; Liu, Hanli

    2007-02-01

    This study aimed at determining cerebral hemodynamic parameters in human subjects during breath holding using near infrared spectroscopy (NIRS). Breath holding serves as a method of simulation OSA (Obstructive Sleep Apnea). Data was acquired non-invasively from 40 subjects, twenty OSA sufferers (10 females, 10 males, age 20-70 years), and twenty normal volunteers (10 females, 10 males, age 20-65 years). Measurements were conducted using a LED Imager (LEDI) during breath holding. In comparing OSA subjects with controls during breath holding, a consistent increase or even a decrease in oxy- ([O IIHb]), deoxy- ([HHb]), total hemoglobin ([tHb]) concentrations, and tissue hemoglobin oxygen saturation (SO II) in the regional brain tissue were observed. The LEDI probe consists of 4 sources and 10 detectors serving as 4 sets of 1 source and 4 detectors each. A three wavelength (730, 805, and 850 nm) LED was used and the wavelengths were switched sequentially. The distance between sources and the source-detector separation were 2.5 cm. Data acquisition consisted of three segments, baseline for one minute, followed by a period of breath holding, and then 2 minutes of recovery time. The duration of the breath holding was subject-dependent. Our investigation proves that NIR spectroscopy could be used as a tool for detecting cerebral hemodynamics and also serves as a method of screening patients with OSA.

  16. A new method for the in vivo identification of mechanical properties in arteries from cine MRI images: theoretical framework and validation.

    PubMed

    Franquet, Alexandre; Avril, Stéphane; Le Riche, Rodolphe; Badel, Pierre; Schneider, Fabien C; Li, Zhi Yong; Boissier, Christian; Favre, Jean Pierre

    2013-08-01

    Quantifying the stiffness properties of soft tissues is essential for the diagnosis of many cardiovascular diseases such as atherosclerosis. In these pathologies it is widely agreed that the arterial wall stiffness is an indicator of vulnerability. The present paper focuses on the carotid artery and proposes a new inversion methodology for deriving the stiffness properties of the wall from cine-MRI (magnetic resonance imaging) data. We address this problem by setting-up a cost function defined as the distance between the modeled pixel signals and the measured ones. Minimizing this cost function yields the unknown stiffness properties of both the arterial wall and the surrounding tissues. The sensitivity of the identified properties to various sources of uncertainty is studied. Validation of the method is performed on a rubber phantom. The elastic modulus identified using the developed methodology lies within a mean error of 9.6%. It is then applied to two young healthy subjects as a proof of practical feasibility, with identified values of 625 kPa and 587 kPa for one of the carotid of each subject. PMID:23591477

  17. SU-D-18A-06: Variation of Controlled Breath Hold From CT Simulation to Treatment and Its Dosimetric Impact for Left-Sided Breast Radiotherapy with a Real-Time Optical Tracking System

    SciTech Connect

    Mittauer, K; Deraniyagala, R; Li, J; Lu, B; Liu, C; Lightsey, J; Yan, G

    2014-06-01

    Purpose: Different breath-hold (BH) maneuvers (abdominal breathing vs. chest breathing) during CT simulation and treatment can lead to chest wall positional variation. The purpose of this study is to quantify the variation of active breathing control (ABC)-assisted BH and estimate its dosimetric impact for left-sided whole-breast radiotherapy with a real-time optical tracking system (OTS). Methods: Seven breast cancer patients were included. An in-house OTS tracked an infrared (IR) marker affixed over the xiphoid process of the patient at CT simulation and throughout the treatment course to measure BH variations. Correlation between the IR marker and the breast was studied for dosimetric purposes. The positional variations of 860 BHs were retrospectively incorporated into treatment plans to assess their dosimetric impact on breast and cardiac organs (heart and left anterior descending artery [LAD]). Results: The mean intrafraction variations were 2.8 mm, 2.7 mm, and 1.6 mm in the anteroposterior (AP), craniocaudal (CC), and mediolateral (ML) directions, respectively. Mean stability in any direction was within 1.5 mm. A general trend of BH undershoot at treatment relative to CT simulation was observed with an average of 4.4 mm, 3.6 mm, and 0.1 mm in the AP, CC, and ML directions, respectively. Undershoot up to 12.6 mm was observed for individual patients. The difference between the planned and delivered dose to breast targets was negligible. The average planned/delivered mean heart doses, mean LAD doses, and max LAD doses were 1.4/2.1, 7.4/15.7, and 18.6/31.0 Gy, respectively. Conclusion: Systematic undershoot was observed in ABC-assisted BHs from CT simulation to treatment. Its dosimetric impact on breast coverage was minimized with image guidance, but the benefits of cardiac organ sparing were degraded. A real-time tracking system can be used in junction with the ABC device to improve BH reproducibility.

  18. SU-E-T-426: Dose Delivery Accuracy in Breast Field Junction for Free Breath and Deep Inspiration Breath Hold Techniques

    SciTech Connect

    Epstein, D; Shekel, E; Levin, D

    2014-06-01

    Purpose: The purpose of this work was to verify the accuracy of the dose distribution along the field junction in a half beam irradiation technique for breast cancer patients receiving radiation to the breast or chest wall (CW) and the supraclavicular LN region for both free breathing and deep inspiration breath hold (DIBH) technique. Methods: We performed in vivo measurements for nine breast cancer patients receiving radiation to the breast/CW and to the supraclavicular LN region. Six patients were treated to the left breast/CW using DIBH technique and three patients were treated to the right breast/CW in free breath. We used five microMOSFET dosimeters: three located along the field junction, one located 1 cm above the junction and the fifth microMOSFET located 1 cm below the junction. We performed consecutive measurements over several days for each patient and compared the measurements to the TPS calculation (Eclipse, Varian™). Results: The calculated and measured doses along the junction were 0.97±0.08 Gy and 1.02±0.14 Gy, respectively. Above the junction calculated and measured doses were 0.91±0.08 Gy and 0.98±0.09 Gy respectively, and below the junction calculated and measured doses were 1.70±0.15 Gy and 1.61±0.09 Gy, respectively. All differences were not statistically significant. When comparing calculated and measured doses for DIBH patients only, there was still no statistically significant difference between values for all dosimeter locations. Analysis was done using the Mann-Whitney Rank-Sum Test. Conclusion: We found excellent correlation between calculated doses from the TPS and measured skin doses at the junction of several half beam fields. Even for the DIBH technique, where there is more potential for variance due to depth of breath, there is no over or underdose along the field junction. This correlation validates the TPS, as well an accurate, reproducible patient setup.

  19. Motion-compensated compressed sensing for dynamic imaging

    NASA Astrophysics Data System (ADS)

    Sundaresan, Rajagopalan; Kim, Yookyung; Nadar, Mariappan S.; Bilgin, Ali

    2010-08-01

    The recently introduced Compressed Sensing (CS) theory explains how sparse or compressible signals can be reconstructed from far fewer samples than what was previously believed possible. The CS theory has attracted significant attention for applications such as Magnetic Resonance Imaging (MRI) where long acquisition times have been problematic. This is especially true for dynamic MRI applications where high spatio-temporal resolution is needed. For example, in cardiac cine MRI, it is desirable to acquire the whole cardiac volume within a single breath-hold in order to avoid artifacts due to respiratory motion. Conventional MRI techniques do not allow reconstruction of high resolution image sequences from such limited amount of data. Vaswani et al. recently proposed an extension of the CS framework to problems with partially known support (i.e. sparsity pattern). In their work, the problem of recursive reconstruction of time sequences of sparse signals was considered. Under the assumption that the support of the signal changes slowly over time, they proposed using the support of the previous frame as the "known" part of the support for the current frame. While this approach works well for image sequences with little or no motion, motion causes significant change in support between adjacent frames. In this paper, we illustrate how motion estimation and compensation techniques can be used to reconstruct more accurate estimates of support for image sequences with substantial motion (such as cardiac MRI). Experimental results using phantoms as well as real MRI data sets illustrate the improved performance of the proposed technique.

  20. Cine CT technique for dynamic airway studies

    SciTech Connect

    Ell, S.R.; Jolles, H.; Keyes, W.D.; Galvin, J.R.

    1985-07-01

    The advent of cine CT scanning with its 50-msec data acquisition time promises a much wider range of dynamic CT studies. The authors describe a method for dynamic evaluation of the extrathoracic airway, which they believe has considerable potential application in nonfixed upper-airway disease, such as sleep apnea and stridor of unknown cause. Conventional CT is limited in such studies by long data acquisition time and can be used to study only prolonged maneuvers such as phonation. Fluoroscopy and digital subtraction studies are limited by relatively high radiation dose and inability to image all wall motions simultaneously.

  1. Left Ventricle: Fully Automated Segmentation Based on Spatiotemporal Continuity and Myocardium Information in Cine Cardiac Magnetic Resonance Imaging (LV-FAST)

    PubMed Central

    Wang, Lijia; Pei, Mengchao; Codella, Noel C. F.; Kochar, Minisha; Weinsaft, Jonathan W.; Li, Jianqi; Prince, Martin R.

    2015-01-01

    CMR quantification of LV chamber volumes typically and manually defines the basal-most LV, which adds processing time and user-dependence. This study developed an LV segmentation method that is fully automated based on the spatiotemporal continuity of the LV (LV-FAST). An iteratively decreasing threshold region growing approach was used first from the midventricle to the apex, until the LV area and shape discontinued, and then from midventricle to the base, until less than 50% of the myocardium circumference was observable. Region growth was constrained by LV spatiotemporal continuity to improve robustness of apical and basal segmentations. The LV-FAST method was compared with manual tracing on cardiac cine MRI data of 45 consecutive patients. Of the 45 patients, LV-FAST and manual selection identified the same apical slices at both ED and ES and the same basal slices at both ED and ES in 38, 38, 38, and 41 cases, respectively, and their measurements agreed within −1.6 ± 8.7 mL, −1.4 ± 7.8 mL, and 1.0 ± 5.8% for EDV, ESV, and EF, respectively. LV-FAST allowed LV volume-time course quantitatively measured within 3 seconds on a standard desktop computer, which is fast and accurate for processing the cine volumetric cardiac MRI data, and enables LV filling course quantification over the cardiac cycle. PMID:25738153

  2. 3D Breath-Held Cardiac Function With Projection Reconstruction in Steady State Free Precession Validated Using 2D Cine MRI

    PubMed Central

    Peters, Dana C.; Ennis, Daniel B.; Rohatgi, Pratik; Syed, Mushabbar A.; McVeigh, Elliot R.; Arai, Andrew E.

    2007-01-01

    Purpose: To develop and validate a three-dimensional (3D) single breath-hold, projection reconstruction (PR), balanced steady state free precession (SSFP) method for cardiac function evaluation against a two-dimensional (2D) multislice Fourier (Cartesian) transform (FT) SSFP method. Materials and Methods: The 3D PR SSFP sequence used projections in the x-y plane and partitions in z, providing 70–80 msec temporal resolution and 1.7 × 1.7 × 8–10 mm in a 24-heartbeat breath hold. A total of 10 volunteers were imaged with both methods, and the measurements of global cardiac function were compared. Results: Mean signal-to-noise ratios (SNRs) for the blood and myocardium were 114 and 42 (2D) and 59 and 21 (3D). Bland-Altman analysis comparing the 2D and 3D ejection fraction (EF), left ventricular end diastolic volume (LVEDV) and end systolic volume (LVESV), and end diastolic myocardial mass (LVEDM) provided values of bias ±2 SD of 0.6% ± 7.7 % for LVEF, 5.9 mL ± 20 mL for LVEDV, −2.8 mL ± 12 mL for LVESV, and −0.61 g ± 13 g for LVEDM. 3D interobserver variability was greater than 2D for LVEDM and LVESV. Conclusion: In a single breath hold, the 3D PR method provides comparable information to the standard 2D FT method, which employs 10–12 breath holds. PMID:15332248

  3. High resolution MR imaging of the fetal heart with cardiac triggering: a feasibility study in the sheep fetus.

    PubMed

    Yamamura, Jin; Schnackenburg, Bernhard; Kooijmann, Hendrik; Frisch, Michael; Hecher, Kurt; Adam, Gerhard; Wedegärtner, Ulrike

    2009-10-01

    The aim of this study was to perform fetal cardiac magnetic resonance imaging (MRI) with triggering of the fetal heart beat in utero in a sheep model. All experimental protocols were reviewed and the usage of ewes and fetuses was approved by the local animal protection authorities. Images of the hearts of six pregnant ewes were obtained by using a 1.5-T MR system (Philips Medical Systems, Best, Netherlands). The fetuses were chronically instrumented with a carotid catheter to measure the fetal heart frequency for the cardiac triggering. Pulse wave triggered, breath-hold cine-MRI with steady-state free precession (SSFP) was achieved in short axis, two-, four- and three-chamber views. The left ventricular volume and thus the function were measured from the short axis. The fetal heart frequencies ranged between 130 and 160 bpm. The mitral, tricuspid, aortic, and pulmonary valves could be clearly observed. The foramen ovale could be visualized. Myocardial contraction was shown in cine sequences. The average blood volume at the end systole was 3.4 + or - 0.2 ml (+ or - SD). The average volume at end diastole was 5.2 + or - 0.2 ml; thus the stroke volumes of the left ventricle in the systole were between 1.7 and 1.9 ml with ejection fractions of 38.6% and 39%, respectively. The pulse wave triggered cardiac MRI of the fetal heart allowed evaluation of anatomical structures and functional information. This feasibility study demonstrates the applicability of MRI for future evaluation of fetuses with complex congenital heart defects, once a noninvasive method has been developed to perform fetal cardiac triggering. PMID:19430796

  4. Clinical evaluation of X-ray voxel Monte Carlo versus pencil beam-based dose calculation in stereotactic body radiotherapy of lung cancer under normal and deep inspiration breath hold.

    PubMed

    Landoni, V; Borzì, G R; Strolin, S; Bruzzaniti, V; Soriani, A; D'Alessio, D; Ambesi, F; Di Grazia, A M; Strigari, L

    2015-06-01

    The purpose of this study is to evaluate the differences between dose distributions calculated with the pencil beam (PB) and X-ray voxel Monte Carlo (MC) algorithms for patients with lung cancer using intensity-modulated radiotherapy (IMRT) or HybridArc techniques. The 2 algorithms were compared in terms of dose-volume histograms, under normal and deep inspiration breath hold, and in terms of the tumor control probability (TCP). The dependence of the differences in tumor volume and location was investigated. Dosimetric validation was performed using Gafchromic EBT3 (International Specialty Products, ISP, Wayne, NJ). Forty-five Computed Tomography (CT) data sets were used for this study; 40 Gy at 8 Gy/fraction was prescribed with 5 noncoplanar 6-MV IMRT beams or 3 to 4 dynamic conformal arcs with 3 to 5 IMRT beams distributed per arc. The plans were first calculated with PB and then recalculated with MC. The difference between the mean tumor doses was approximately 10% ± 4%; these differences were even larger under deep inspiration breath hold. Differences between the mean tumor dose correlated with tumor volume and path length of the beams. The TCP values changed from 99.87% ± 0.24% to 96.78% ± 4.81% for both PB- and MC-calculated plans (P = .009). When a fraction of hypoxic cells was considered, the mean TCP values changed from 76.01% ± 5.83% to 34.78% ± 18.06% for the differently calculated plans (P < .0001). When the plans were renormalized to the same mean dose at the tumor, the mean TCP for oxic cells was 99.05% ± 1.59% and for hypoxic cells was 60.20% ± 9.53%. This study confirms that the MC algorithm adequately accounts for inhomogeneities. The inclusion of the MC in the process of IMRT optimization could represent a further step in the complex problem of determining the optimal treatment plan. PMID:25223324

  5. Organ perfusion during voluntary pulmonary hyperinflation; a magnetic resonance imaging study.

    PubMed

    Kyhl, Kasper; Drvis, Ivan; Barak, Otto; Mijacika, Tanja; Engstrøm, Thomas; Secher, Niels H; Dujic, Zeljko; Buca, Ante; Madsen, Per Lav

    2016-02-01

    Pulmonary hyperinflation is used by competitive breath-hold divers and is accomplished by glossopharyngeal insufflation (GPI), which is known to compress the heart and pulmonary vessels, increasing sympathetic activity and lowering cardiac output (CO) without known consequence for organ perfusion. Myocardial, pulmonary, skeletal muscle, kidney, and liver perfusion were evaluated by magnetic resonance imaging in 10 elite breath-hold divers at rest and during moderate GPI. Cardiac chamber volumes, stroke volume, and thus CO were determined from cardiac short-axis cine images. Organ volumes were assessed from gradient echo sequences, and organ perfusion was evaluated from first-pass images after gadolinium injection. During GPI, lung volume increased by 5.2 ± 1.5 liters (mean ± SD; P < 0.001), while spleen and liver volume decreased by 46 ± 39 and 210 ± 160 ml, respectively (P < 0.05), and inferior caval vein diameter by 4 ± 3 mm (P < 0.05). Heart rate tended to increase (67 ± 10 to 86 ± 20 beats/min; P = 0.052) as right and left ventricular volumes were reduced (P < 0.05). Stroke volume (107 ± 21 to 53 ± 15 ml) and CO (7.2 ± 1.6 to 4.2 ± 0.8 l/min) decreased as assessed after 1 min of GPI (P < 0.01). Left ventricular myocardial perfusion maximum upslope and its perfusion index decreased by 1.52 ± 0.15 s(-1) (P < 0.001) and 0.02 ± 0.01 s(-1) (P < 0.05), respectively, without transmural differences. Pulmonary tissue, spleen, kidney, and pectoral-muscle perfusion also decreased (P < 0.05), and yet liver perfusion was maintained. Thus, during pulmonary hyperinflation by GPI, CO and organ perfusion, including the myocardium, as well as perfusion of skeletal muscles, are reduced, and yet perfusion of the liver is maintained. Liver perfusion seems to be prioritized when CO decreases during GPI. PMID:26589331

  6. Dynamic Multiscale Boundary Conditions for 4D CT Images of Healthy and Emphysematous Rat

    SciTech Connect

    Jacob, Rick E.; Carson, James P.; Thomas, Mathew; Einstein, Daniel R.

    2013-06-14

    Changes in the shape of the lung during breathing determine the movement of airways and alveoli, and thus impact airflow dynamics. Modeling airflow dynamics in health and disease is a key goal for predictive multiscale models of respiration. Past efforts to model changes in lung shape during breathing have measured shape at multiple breath-holds. However, breath-holds do not capture hysteretic differences between inspiration and expiration resulting from the additional energy required for inspiration. Alternatively, imaging dynamically – without breath-holds – allows measurement of hysteretic differences. In this study, we acquire multiple micro-CT images per breath (4DCT) in live rats, and from these images we develop, for the first time, dynamic volume maps. These maps show changes in local volume across the entire lung throughout the breathing cycle and accurately predict the global pressure-volume (PV) hysteresis.

  7. Compressed sensing reconstruction of cardiac cine MRI using golden angle spiral trajectories

    NASA Astrophysics Data System (ADS)

    Tolouee, Azar; Alirezaie, Javad; Babyn, Paul

    2015-11-01

    In dynamic cardiac cine Magnetic Resonance Imaging (MRI), the spatiotemporal resolution is limited by the low imaging speed. Compressed sensing (CS) theory has been applied to improve the imaging speed and thus the spatiotemporal resolution. The purpose of this paper is to improve CS reconstruction of under sampled data by exploiting spatiotemporal sparsity and efficient spiral trajectories. We extend k-t sparse algorithm to spiral trajectories to achieve high spatio temporal resolutions in cardiac cine imaging. We have exploited spatiotemporal sparsity of cardiac cine MRI by applying a 2D + time wavelet-Fourier transform. For efficient coverage of k-space, we have used a modified version of multi shot (interleaved) spirals trajectories. In order to reduce incoherent aliasing artifact, we use different random undersampling pattern for each temporal frame. Finally, we have used nonuniform fast Fourier transform (NUFFT) algorithm to reconstruct the image from the non-uniformly acquired samples. The proposed approach was tested in simulated and cardiac cine MRI data. Results show that higher acceleration factors with improved image quality can be obtained with the proposed approach in comparison to the existing state-of-the-art method. The flexibility of the introduced method should allow it to be used not only for the challenging case of cardiac imaging, but also for other patient motion where the patient moves or breathes during acquisition.

  8. An image acquisition and registration strategy for the fusion of hyperpolarized helium-3 MRI and x-ray CT images of the lung

    NASA Astrophysics Data System (ADS)

    Ireland, Rob H.; Woodhouse, Neil; Hoggard, Nigel; Swinscoe, James A.; Foran, Bernadette H.; Hatton, Matthew Q.; Wild, Jim M.

    2008-11-01

    The purpose of this ethics committee approved prospective study was to evaluate an image acquisition and registration protocol for hyperpolarized helium-3 magnetic resonance imaging (3He-MRI) and x-ray computed tomography. Nine patients with non-small cell lung cancer (NSCLC) gave written informed consent to undergo a free-breathing CT, an inspiration breath-hold CT and a 3D ventilation 3He-MRI in CT position using an elliptical birdcage radiofrequency (RF) body coil. 3He-MRI to CT image fusion was performed using a rigid registration algorithm which was assessed by two observers using anatomical landmarks and a percentage volume overlap coefficient. Registration of 3He-MRI to breath-hold CT was more accurate than to free-breathing CT; overlap 82.9 ± 4.2% versus 59.8 ± 9.0% (p < 0.001) and mean landmark error 0.75 ± 0.24 cm versus 1.25 ± 0.60 cm (p = 0.002). Image registration is significantly improved by using an imaging protocol that enables both 3He-MRI and CT to be acquired with similar breath holds and body position through the use of a birdcage 3He-MRI body RF coil and an inspiration breath-hold CT. Fusion of 3He-MRI to CT may be useful for the assessment of patients with lung diseases.

  9. Cine Computed Tomography Without Respiratory Surrogate in Planning Stereotactic Radiotherapy for Non-Small-Cell Lung Cancer

    SciTech Connect

    Riegel, Adam C. B.A.; Chang, Joe Y.; Vedam, Sastry S.; Johnson, Valen; Chi, Pai-Chun Melinda; Pan, Tinsu

    2009-02-01

    Purpose: To determine whether cine computed tomography (CT) can serve as an alternative to four-dimensional (4D)-CT by providing tumor motion information and producing equivalent target volumes when used to contour in radiotherapy planning without a respiratory surrogate. Methods and Materials: Cine CT images from a commercial CT scanner were used to form maximum intensity projection and respiratory-averaged CT image sets. These image sets then were used together to define the targets for radiotherapy. Phantoms oscillating under irregular motion were used to assess the differences between contouring using cine CT and 4D-CT. We also retrospectively reviewed the image sets for 26 patients (27 lesions) at our institution who had undergone stereotactic radiotherapy for Stage I non-small-cell lung cancer. The patients were included if the tumor motion was >1 cm. The lesions were first contoured using maximum intensity projection and respiratory-averaged CT image sets processed from cine CT and then with 4D-CT maximum intensity projection and 10-phase image sets. The mean ratios of the volume magnitude were compared with intraobserver variation, the mean centroid shifts were calculated, and the volume overlap was assessed with the normalized Dice similarity coefficient index. Results: The phantom studies demonstrated that cine CT captured a greater extent of irregular tumor motion than did 4D-CT, producing a larger tumor volume. The patient studies demonstrated that the gross tumor defined using cine CT imaging was similar to, or slightly larger than, that defined using 4D-CT. Conclusion: The results of our study have shown that cine CT is a promising alternative to 4D-CT for stereotactic radiotherapy planning.

  10. Automatic localization of the left ventricle from cardiac cine magnetic resonance imaging: a new spectrum-based computer-aided tool.

    PubMed

    Zhong, Liang; Zhang, Jun-Mei; Zhao, Xiaodan; Tan, Ru San; Wan, Min

    2014-01-01

    Traditionally, cardiac image analysis is done manually. Automatic image processing can help with the repetitive tasks, and also deal with huge amounts of data, a task which would be humanly tedious. This study aims to develop a spectrum-based computer-aided tool to locate the left ventricle using images obtained via cardiac magnetic resonance imaging. Discrete Fourier Transform was conducted pixelwise on the image sequence. Harmonic images of all frequencies were analyzed visually and quantitatively to determine different patterns of the left and right ventricles on spectrum. The first and fifth harmonic images were selected to perform an anisotropic weighted circle Hough detection. This tool was then tested in ten volunteers. Our tool was able to locate the left ventricle in all cases and had a significantly higher cropping ratio of 0.165 than did earlier studies. In conclusion, a new spectrum-based computer aided tool has been proposed and developed for automatic left ventricle localization. The development of this technique, which will enable the automatic location and further segmentation of the left ventricle, will have a significant impact in research and in diagnostic settings. We envisage that this automated method could be used by radiographers and cardiologists to diagnose and assess ventricular function in patients with diverse heart diseases. PMID:24722328

  11. TH-A-BRF-04: Intra-Fraction Motion Characterization for Early Stage Rectal Cancer Using Cine-MRI

    SciTech Connect

    Kleijnen, J; Asselen, B; Burbach, M; Intven, M; Reerink, O; Philippens, M; Lagendijk, J; Raaymakers, B

    2014-06-15

    Purpose: To investigate the intra-fraction motion in patients with early stage rectal cancer using cine-MRI. Methods: Sixteen patient diagnosed with early stage rectal cancer underwent 1.5 T MR imaging prior to each treatment fraction of their short course radiotherapy (n=76). During each scan session, three 2D sagittal cine-MRIs were performed: at the beginning (Start), after 9:30 minutes (Mid), and after 18 minutes (End). Each cine-MRI has a duration of one minute at 2Hz temporal resolution, resulting in a total of 3:48 hours of cine-MRI. Additionally, standard T2-weighted (T2w) imaging was performed. Clinical target volume (CTV) an tumor (GTV) were delineated on the T2w scan and transferred to the first time-point of each cine-MRI scan. Within each cine-MRI, the first frame was registered to the remaining frames of the scan, using a non-rigid B-spline registration. To investigate potential drifts, a similar registration was performed between the first frame of the Start and End scans.To evaluate the motion, the distances by which the edge pixels of the delineations move in anterior-posterior (AP) and cranial-caudal (CC) direction, were determined using the deformation field of the registrations. The distance which incorporated 95% of these edge pixels (dist95%) was determined within each cine-MRI, and between Start- End scans, respectively. Results: Within a cine-MRI, we observed an average dist95% for the CTV of 1.3mm/1.5mm (SD=0.7mm/0.6mm) and for the GTV of 1.2mm/1.5mm (SD=0.8mm/0.9mm), in respectively AP/CC. For the CTV motion between the Start and End scan, an average dist95% of 5.5mm/5.3mm (SD=3.1mm/2.5mm) was found, in respectively AP/CC. For the GTV motion, an average dist95% of 3.6mm/3.9mm (SD=2.2mm/2.5mm) was found in AP/CC, respectively. Conclusion: Although intra-fraction motion within a one minute cine-MRI is limited, substantial intra-fraction motion was observed within the 18 minute time period between the Start and End cine-MRI.

  12. Motion prediction in MRI-guided radiotherapy based on interleaved orthogonal cine-MRI

    NASA Astrophysics Data System (ADS)

    Seregni, M.; Paganelli, C.; Lee, D.; Greer, P. B.; Baroni, G.; Keall, P. J.; Riboldi, M.

    2016-01-01

    In-room cine-MRI guidance can provide non-invasive target localization during radiotherapy treatment. However, in order to cope with finite imaging frequency and system latencies between target localization and dose delivery, tumour motion prediction is required. This work proposes a framework for motion prediction dedicated to cine-MRI guidance, aiming at quantifying the geometric uncertainties introduced by this process for both tumour tracking and beam gating. The tumour position, identified through scale invariant features detected in cine-MRI slices, is estimated at high-frequency (25 Hz) using three independent predictors, one for each anatomical coordinate. Linear extrapolation, auto-regressive and support vector machine algorithms are compared against systems that use no prediction or surrogate-based motion estimation. Geometric uncertainties are reported as a function of image acquisition period and system latency. Average results show that the tracking error RMS can be decreased down to a [0.2; 1.2] mm range, for acquisition periods between 250 and 750 ms and system latencies between 50 and 300 ms. Except for the linear extrapolator, tracking and gating prediction errors were, on average, lower than those measured for surrogate-based motion estimation. This finding suggests that cine-MRI guidance, combined with appropriate prediction algorithms, could relevantly decrease geometric uncertainties in motion compensated treatments.

  13. Electronic fluorography for the performance of cine hysterosalpingography

    SciTech Connect

    Freedman, M.; Farber, M.; Edelstein, G.; Tildon-Burton, J.; Gill, E.

    1987-04-01

    We used electronic fluorography to perform hysterosalpingography in 25 women with infertility or abnormal bleeding. In contrast to the conventional modality of fluoroscopy with intermittent permanent imaging, an image intensifier was used to periodically record dye injection on a moving tape (cine hysterosalpingography). The mean number of electronic fluorographs taken per patient was 10.8 +/- 3.12 (mean +/- SD). The mean radiation exposure per patient for electronic fluorography was 113.4 +/- 52 versus 112 +/- 52.4 mR when a single conventional radiographic image was taken. We conclude that electronic fluorography is a simple yet accurate radiographic method that delivers to the gonads approximately one-eleventh the dose of ionizing radiation that current standard techniques do, and should be accepted as an alternative diagnostic modality.

  14. Cine EPID evaluation of two non-commercial techniques for DIBH

    PubMed Central

    Jensen, Christopher; Urribarri, Jaime; Cail, Daniel; Rottmann, Joerg; Mishra, Pankaj; Lingos, Tatiana; Niedermayr, Thomas; Berbeco, Ross

    2014-01-01

    Purpose: To evaluate the efficacy of two noncommercial techniques for deep inspiration breathhold (DIBH) treatment of left-sided breast cancer (LSBC) using cine electronic portal imaging device (EPID) images. Methods: 23 875 EPID images of 65 patients treated for LSBC at two different cancer treatment centers were retrieved. At the Milford Regional Cancer Center, DIBH stability was maintained by visual alignment of inroom lasers and patient skin tattoos (TAT). At the South Shore Hospital, a distance-measuring laser device (RTSSD) was implemented. For both centers, cine EPID images were acquired at least once per week during beam-on. Chest wall position relative to image boundary was measured and tracked over the course of treatment for every patient and treatment fraction for which data were acquired. Results: Median intrabeam chest motion was 0.31 mm for the TAT method and 0.37 mm for the RTSSD method. The maximum excursions exceeded our treatment protocol threshold of 3 mm in 0.3% of cases (TAT) and 1.2% of cases (RTSSD). The authors did not observe a clinically significant difference between the two datasets. Conclusions: Both noncommercial techniques for monitoring the DIBH location provided DIBH stability within the predetermined treatment protocol parameters (<3 mm). The intreatment imaging offered by the EPID operating in cine mode facilitates retrospective analysis and validation of both techniques. PMID:24506621

  15. Digital tomosynthesis with an on-board kilovoltage imaging device

    SciTech Connect

    Godfrey, Devon J. . E-mail: devon.godfrey@duke.edu; Yin, F.-F.; Oldham, Mark; Yoo, Sua; Willett, Christopher

    2006-05-01

    Purpose: To generate on-board digital tomosynthesis (DTS) and reference DTS images for three-dimensional image-guided radiation therapy (IGRT) as an alternative to conventional portal imaging or on-board cone-beam computed tomography (CBCT). Methods and Materials: Three clinical cases (prostate, head-and-neck, and liver) were selected to illustrate the capabilities of on-board DTS for IGRT. Corresponding reference DTS images were reconstructed from digitally reconstructed radiographs computed from planning CT image sets. The effect of scan angle on DTS slice thickness was examined by computing the mutual information between coincident CBCT and DTS images, as the DTS scan angle was varied from 0{sup o} to 165{sup o}. A breath-hold DTS acquisition strategy was implemented to remove respiratory motion artifacts. Results: Digital tomosynthesis slices appeared similar to coincident CBCT planes and yielded substantially more anatomic information than either kilovoltage or megavoltage radiographs. Breath-hold DTS acquisition improved soft-tissue visibility by suppressing respiratory motion. Conclusions: Improved bony and soft-tissue visibility in DTS images is likely to improve target localization compared with radiographic verification techniques and might allow for daily localization of a soft-tissue target. Breath-hold DTS is a potential alternative to on-board CBCT for sites prone to respiratory motion.

  16. Requirements and Solutions for Archiving Scientific Data at CINES

    NASA Astrophysics Data System (ADS)

    Coutin, Stephane

    Historically an high-performance computing datacenter, the “Centre Informatique National de l’Enseignement Supérieur” (CINES) has also a mission of long term digital preservation. By coupling those two areas, it became obvious that CINES had to understand and take into account the requirements of scientific communities regarding their data life cycle, and more specifically their archiving requirements. We will present those requirements and describe the platforms CINES proposes for each service class.

  17. Use of cine phase-contrast MRI in the assessment of distal splenorenal shunt function.

    PubMed

    Cabassa, Paolo; Ravanelli, Marco; Alberti, Daniele; Maroldi, Roberto

    2012-06-01

    Magnetic resonance imaging (MRI) features of a surgical splenorenal shunt in a 28-year-old girl are described. The woman underwent color doppler ultrasonography during follow up for the shunt, which was inconclusive. MR was used to investigate the function of the shunt. Velocity and flow direction in splanchnic vessels and in the shunt were evaluated using cine fast phase-contrast sequences. MR findings could be of help in the evaluation of patients undergoing surgical shunts during follow up. PMID:22405982

  18. SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

    SciTech Connect

    Lafata, K; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J

    2014-06-01

    Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D images were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/− 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21

  19. Tissue-point motion tracking in the tongue from cine MRI and tagged MRI.

    PubMed

    Woo, Jonghye; Stone, Maureen; Suo, Yuanming; Murano, Emi Z; Prince, Jerry L

    2014-04-01

    PURPOSE Accurate tissue motion tracking within the tongue can help professionals diagnose and treat vocal tract-related disorders, evaluate speech quality before and after surgery, and conduct various scientific studies. The authors compared tissue tracking results from 4 widely used deformable registration (DR) methods applied to cine magnetic resonance imaging (MRI) with harmonic phase (HARP)-based tracking applied to tagged MRI. METHOD Ten subjects repeated the phrase "a geese" multiple times while sagittal images of the head were collected at 26 Hz, first in a tagged MRI data set and then in a cine MRI data set. HARP tracked the motion of 8 specified tissue points in the tagged data set. Four DR methods including diffeomorphic demons and free-form deformations based on cubic B-spline with 3 different similarity measures were used to track the same 8 points in the cine MRI data set. Individual points were tracked and length changes of several muscles were calculated using the DR- and HARP-based tracking methods. RESULTS The results showed that the DR tracking errors were nonsystematic and varied in direction, amount, and timing across speakers and within speakers. Comparison of HARP and DR tracking with manual tracking showed better tracking results for HARP except at the tongue surface, where mistracking caused greater errors in HARP than DR. CONCLUSIONS Tissue point tracking using DR tracking methods contains nonsystematic tracking errors within and across subjects, making it less successful than tagged MRI tracking within the tongue. However, HARP sometimes mistracks points at the tongue surface of tagged MRI because of its limited bandpass filter and tag pattern fading, so that DR has better success measuring surface tissue points on cine MRI than HARP does. Therefore, a hybrid method is being explored. PMID:24686470

  20. Evaluation of potential internal target volume of liver tumors using cine-MRI

    SciTech Connect

    Akino, Yuichi; Oh, Ryoong-Jin; Masai, Norihisa; Shiomi, Hiroya; Inoue, Toshihiko

    2014-11-01

    Purpose: Four-dimensional computed tomography (4DCT) is widely used for evaluating moving tumors, including lung and liver cancers. For patients with unstable respiration, however, the 4DCT may not visualize tumor motion properly. High-speed magnetic resonance imaging (MRI) sequences (cine-MRI) permit direct visualization of respiratory motion of liver tumors without considering radiation dose exposure to patients. Here, the authors demonstrated a technique for evaluating internal target volume (ITV) with consideration of respiratory variation using cine-MRI. Methods: The authors retrospectively evaluated six patients who received stereotactic body radiotherapy (SBRT) to hepatocellular carcinoma. Before acquiring planning CT, sagittal and coronal cine-MRI images were acquired for 30 s with a frame rate of 2 frames/s. The patient immobilization was conducted under the same condition as SBRT. Planning CT images were then acquired within 15 min from cine-MRI image acquisitions, followed by a 4DCT scan. To calculate tumor motion, the motion vectors between two continuous frames of cine-MRI images were calculated for each frame using the pyramidal Lucas–Kanade method. The target contour was delineated on one frame, and each vertex of the contour was shifted and copied onto the following frame using neighboring motion vectors. 3D trajectory data were generated with the centroid of the contours on sagittal and coronal images. To evaluate the accuracy of the tracking method, the motion of clearly visible blood vessel was analyzed with the motion tracking and manual detection techniques. The target volume delineated on the 50% (end-exhale) phase of 4DCT was translated with the trajectory data, and the distribution of the occupancy probability of target volume was calculated as potential ITV (ITV {sub Potential}). The concordance between ITV {sub Potential} and ITV estimated with 4DCT (ITV {sub 4DCT}) was evaluated using the Dice’s similarity coefficient (DSC). Results

  1. Machine learning for the automatic localisation of foetal body parts in cine-MRI scans

    NASA Astrophysics Data System (ADS)

    Bowles, Christopher; Nowlan, Niamh C.; Hayat, Tayyib T. A.; Malamateniou, Christina; Rutherford, Mary; Hajnal, Joseph V.; Rueckert, Daniel; Kainz, Bernhard

    2015-03-01

    Being able to automate the location of individual foetal body parts has the potential to dramatically reduce the work required to analyse time resolved foetal Magnetic Resonance Imaging (cine-MRI) scans, for example, for use in the automatic evaluation of the foetal development. Currently, manual preprocessing of every scan is required to locate body parts before analysis can be performed, leading to a significant time overhead. With the volume of scans becoming available set to increase as cine-MRI scans become more prevalent in clinical practice, this stage of manual preprocessing is a bottleneck, limiting the data available for further analysis. Any tools which can automate this process will therefore save many hours of research time and increase the rate of new discoveries in what is a key area in understanding early human development. Here we present a series of techniques which can be applied to foetal cine-MRI scans in order to first locate and then differentiate between individual body parts. A novel approach to maternal movement suppression and segmentation using Fourier transforms is put forward as a preprocessing step, allowing for easy extraction of short movements of individual foetal body parts via the clustering of optical flow vector fields. These body part movements are compared to a labelled database and probabilistically classified before being spatially and temporally combined to give a final estimate for the location of each body part.

  2. Clinical Applications of Cine Balanced Steady-State Free Precession MRI for the Evaluation of the Subarachnoid Spaces.

    PubMed

    Li, A E; Wilkinson, M D; McGrillen, K M; Stoodley, M A; Magnussen, J S

    2015-12-01

    The purpose of this article is to review the physiology of normal brain and spinal cord motion in the subarachnoid space, principles of cine balanced steady-state free precession (bSSFP) magnetic resonance imaging (MRI), clinical applications, and the pitfalls encountered with this technique. The brain and spinal cord are dynamic structures that move with each heartbeat due to transmitted arterial pulse waves. Conventional MRI sequences do not allow anatomic evaluation of the pulsatile movement of the neural structures in the subarachnoid space due to limitations in temporal resolution. Cine bSSFP MRI uses cardiac gating to evaluate dynamically the brain and spinal cord with high contrast and temporal resolution.Cine bSSFP can be used in the evaluation of idiopathic syringomyelia to assess an underlying treatable cause, including arachnoid bands, which are usually not well visualized with conventional MR sequences due to motion artifact. This MRI technique is also useful in the evaluation of intraspinal and intracranial arachnoid cysts and the degree of mass effect on the cord. Other applications include preoperative and postoperative evaluation of Chiari I malformation and the evaluation of lateral ventricular asymmetry. The major limitation of cine bSSFP is the presence of banding artifacts, which can be reduced by shimming and modifying other scan parameters. PMID:25854921

  3. Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT

    PubMed Central

    2010-01-01

    Background To date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress. Methods 43 patients age 25 to 81 years underwent a treadmill stress test incorporating both Tc99m SPECT and CMR. After rest Tc99m SPECT imaging, patients underwent resting cine CMR. Patients then underwent in-room exercise stress using a partially modified treadmill. 12-lead ECG monitoring was performed throughout. At peak stress, Tc99m was injected and patients rapidly returned to their prior position in the magnet for post-exercise cine and perfusion imaging. The patient table was pulled out of the magnet for recovery monitoring. The patient was sent back into the magnet for recovery cine and resting perfusion followed by delayed post-gadolinium imaging. Post-CMR, patients went to the adjacent SPECT lab to complete stress nuclear imaging. Each modality's images were reviewed blinded to the other's results. Results Patients completed on average 9.3 ± 2.4 min of the Bruce protocol. Stress cine CMR was completed in 68 ± 14 sec following termination of exercise, and stress perfusion CMR was completed in 88 ± 8 sec. Agreement between SPECT and CMR was moderate (κ = 0.58). Accuracy in eight patients who underwent coronary angiography was 7/8 for CMR and 5/8 for SPECT (p = 0.625). Follow-up at 6 months indicated freedom from cardiovascular events in 29/29 CMR-negative and 33/34 SPECT-negative patients. Conclusions Exercise stress CMR including wall motion and perfusion is feasible in patients with suspected ischemic heart disease. Larger clinical trials are warranted based on the promising results of this pilot study to allow comparative effectiveness studies of this stress imaging system vs. other stress imaging modalities. PMID:20624294

  4. A novel technique for VMAT QA with EPID in cine mode on a Varian TrueBeam linac

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Adamson, Justus; Rodrigues, Anna; Zhou, Fugen; Yin, Fang-fang; Wu, Qiuwen

    2013-10-01

    Volumetric modulated arc therapy (VMAT) is a relatively new treatment modality for dynamic photon radiation therapy. Pre-treatment quality assurance (QA) is necessary and many efforts have been made to apply electronic portal imaging device (EPID)-based IMRT QA methods to VMAT. It is important to verify the gantry rotation speed during delivery as this is a new variable that is also modulated in VMAT. In this paper, we present a new technique to perform VMAT QA using an EPID. The method utilizes EPID cine mode and was tested on Varian TrueBeam in research mode. The cine images were acquired during delivery and converted to dose matrices after profile correction and dose calibration. A sub-arc corresponding to each cine image was extracted from the original plan and its portal image prediction was calculated. Several analyses were performed including 3D γ analysis (2D images + gantry angle axis), 2D γ analysis, and other statistical analyses. The method was applied to 21 VMAT photon plans of 3 photon energies. The accuracy of the cine image information was investigated. Furthermore, this method's sensitivity to machine delivery errors was studied. The pass rate (92.8 ± 1.4%) for 3D γ analysis was comparable to those from Delta4 system (99.9 ± 0.1%) under similar criteria (3%, 3 mm, 5% threshold and 2° angle to agreement) at 6 MV. The recorded gantry angle and start/stop MUs were found to have sufficient accuracy for clinical QA. Machine delivery errors can be detected through combined analyses of 3D γ, gantry angle, and percentage dose difference. In summary, we have developed and validated a QA technique that can simultaneously verify the gantry angle and delivered MLC fluence for VMAT treatment.This technique is efficient and its accuracy is comparable to other QA methods.

  5. Using learned under-sampling pattern for increasing speed of cardiac cine MRI based on compressive sensing principles

    NASA Astrophysics Data System (ADS)

    Zamani, Pooria; Kayvanrad, Mohammad; Soltanian-Zadeh, Hamid

    2012-12-01

    This article presents a compressive sensing approach for reducing data acquisition time in cardiac cine magnetic resonance imaging (MRI). In cardiac cine MRI, several images are acquired throughout the cardiac cycle, each of which is reconstructed from the raw data acquired in the Fourier transform domain, traditionally called k-space. In the proposed approach, a majority, e.g., 62.5%, of the k-space lines (trajectories) are acquired at the odd time points and a minority, e.g., 37.5%, of the k-space lines are acquired at the even time points of the cardiac cycle. Optimal data acquisition at the even time points is learned from the data acquired at the odd time points. To this end, statistical features of the k-space data at the odd time points are clustered by fuzzy c-means and the results are considered as the states of Markov chains. The resulting data is used to train hidden Markov models and find their transition matrices. Then, the trajectories corresponding to transition matrices far from an identity matrix are selected for data acquisition. At the end, an iterative thresholding algorithm is used to reconstruct the images from the under-sampled k-space datasets. The proposed approaches for selecting the k-space trajectories and reconstructing the images generate more accurate images compared to alternative methods. The proposed under-sampling approach achieves an acceleration factor of 2 for cardiac cine MRI.

  6. Joint multi-object registration and segmentation of left and right cardiac ventricles in 4D cine MRI

    NASA Astrophysics Data System (ADS)

    Ehrhardt, Jan; Kepp, Timo; Schmidt-Richberg, Alexander; Handels, Heinz

    2014-03-01

    The diagnosis of cardiac function based on cine MRI requires the segmentation of cardiac structures in the images, but the problem of automatic cardiac segmentation is still open, due to the imaging characteristics of cardiac MR images and the anatomical variability of the heart. In this paper, we present a variational framework for joint segmentation and registration of multiple structures of the heart. To enable the simultaneous segmentation and registration of multiple objects, a shape prior term is introduced into a region competition approach for multi-object level set segmentation. The proposed algorithm is applied for simultaneous segmentation of the myocardium as well as the left and right ventricular blood pool in short axis cine MRI images. Two experiments are performed: first, intra-patient 4D segmentation with a given initial segmentation for one time-point in a 4D sequence, and second, a multi-atlas segmentation strategy is applied to unseen patient data. Evaluation of segmentation accuracy is done by overlap coefficients and surface distances. An evaluation based on clinical 4D cine MRI images of 25 patients shows the benefit of the combined approach compared to sole registration and sole segmentation.

  7. Craniocaudal Safety Margin Calculation Based on Interfractional Changes in Tumor Motion in Lung SBRT Assessed With an EPID in Cine Mode

    SciTech Connect

    Ueda, Yoshihiro; Miyazaki, Masayoshi; Nishiyama, Kinji; Suzuki, Osamu; Tsujii, Katsutomo; Miyagi, Ken

    2012-07-01

    Purpose: To evaluate setup error and interfractional changes in tumor motion magnitude using an electric portal imaging device in cine mode (EPID cine) during the course of stereotactic body radiation therapy (SBRT) for non-small-cell lung cancer (NSCLC) and to calculate margins to compensate for these variations. Materials and Methods: Subjects were 28 patients with Stage I NSCLC who underwent SBRT. Respiratory-correlated four-dimensional computed tomography (4D-CT) at simulation was binned into 10 respiratory phases, which provided average intensity projection CT data sets (AIP). On 4D-CT, peak-to-peak motion of the tumor (M-4DCT) in the craniocaudal direction was assessed and the tumor center (mean tumor position [MTP]) of the AIP (MTP-4DCT) was determined. At treatment, the tumor on cone beam CT was registered to that on AIP for patient setup. During three sessions of irradiation, peak-to-peak motion of the tumor (M-cine) and the mean tumor position (MTP-cine) were obtained using EPID cine and in-house software. Based on changes in tumor motion magnitude ( Increment M) and patient setup error ( Increment MTP), defined as differences between M-4DCT and M-cine and between MTP-4DCT and MTP-cine, a margin to compensate for these variations was calculated with Stroom's formula. Results: The means ({+-}standard deviation: SD) of M-4DCT and M-cine were 3.1 ({+-}3.4) and 4.0 ({+-}3.6) mm, respectively. The means ({+-}SD) of Increment M and Increment MTP were 0.9 ({+-}1.3) and 0.2 ({+-}2.4) mm, respectively. Internal target volume-planning target volume (ITV-PTV) margins to compensate for Increment M, Increment MTP, and both combined were 3.7, 5.2, and 6.4 mm, respectively. Conclusion: EPID cine is a useful modality for assessing interfractional variations of tumor motion. The ITV-PTV margins to compensate for these variations can be calculated.

  8. MRI-based measurements of respiratory motion variability and assessment of imaging strategies for radiotherapy planning

    NASA Astrophysics Data System (ADS)

    Blackall, J. M.; Ahmad, S.; Miquel, M. E.; McClelland, J. R.; Landau, D. B.; Hawkes, D. J.

    2006-09-01

    Respiratory organ motion has a significant impact on the planning and delivery of radiotherapy (RT) treatment for lung cancer. Currently widespread techniques, such as 4D-computed tomography (4DCT), cannot be used to measure variability of this motion from one cycle to the next. In this paper, we describe the use of fast magnetic resonance imaging (MRI) techniques to investigate the intra- and inter-cycle reproducibility of respiratory motion and also to estimate the level of errors that may be introduced into treatment delivery by using various breath-hold imaging strategies during lung RT planning. A reference model of respiratory motion is formed to enable comparison of different breathing cycles at any arbitrary position in the respiratory cycle. This is constructed by using free-breathing images from the inhale phase of a single breathing cycle, then co-registering the images, and thereby tracking landmarks. This reference model is then compared to alternative models constructed from images acquired during the exhale phase of the same cycle and the inhale phase of a subsequent cycle, to assess intra- and inter-cycle variability ('hysteresis' and 'reproducibility') of organ motion. The reference model is also compared to a series of models formed from breath-hold data at exhale and inhale. Evaluation of these models is carried out on data from ten healthy volunteers and five lung cancer patients. Free-breathing models show good levels of intra- and inter-cycle reproducibility across the tidal breathing range. Mean intra-cycle errors in the position of organ surface landmarks of 1.5(1.4)-3.5(3.3) mm for volunteers and 2.8(1.8)-5.2(5.2) mm for patients. Equivalent measures of inter-cycle variability across this range are 1.7(1.0)-3.9(3.3) mm for volunteers and 2.8(1.8)-3.3(2.2) mm for patients. As expected, models based on breath-hold sequences do not represent normal tidal motion as well as those based on free-breathing data, with mean errors of 4

  9. 21 CFR 892.1620 - Cine or spot fluorographic x-ray camera.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cine or spot fluorographic x-ray camera. 892.1620... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1620 Cine or spot fluorographic x-ray camera. (a) Identification. A cine or spot fluorographic x-ray camera is a device intended to...

  10. 21 CFR 892.1620 - Cine or spot fluorographic x-ray camera.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cine or spot fluorographic x-ray camera. 892.1620... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1620 Cine or spot fluorographic x-ray camera. (a) Identification. A cine or spot fluorographic x-ray camera is a device intended to...