4-dimensional computed tomography (4D-CT)-based pulmonary ventilation imaging is an emerging functional imaging modality. The purpose of this study was to investigate the physiological significance ...of 4D-CT ventilation imaging by comparison with pulmonary function test (PFT) measurements and single-photon emission CT (SPECT) ventilation images, which are the clinical references for global and regional lung function, respectively.
In an institutional review board-approved prospective clinical trial, 4D-CT imaging and PFT and/or SPECT ventilation imaging were performed in thoracic cancer patients. Regional ventilation (V4DCT) was calculated by deformable image registration of 4D-CT images and quantitative analysis for regional volume change. V4DCT defect parameters were compared with the PFT measurements (forced expiratory volume in 1 second (FEV1; % predicted) and FEV1/forced vital capacity (FVC; %). V4DCT was also compared with SPECT ventilation (VSPECT) to (1) test whether V4DCT in VSPECT defect regions is significantly lower than in nondefect regions by using the 2-tailed t test; (2) to quantify the spatial overlap between V4DCT and VSPECT defect regions with Dice similarity coefficient (DSC); and (3) to test ventral-to-dorsal gradients by using the 2-tailed t test.
Of 21 patients enrolled in the study, 18 patients for whom 4D-CT and either PFT or SPECT were acquired were included in the analysis. V4DCT defect parameters were found to have significant, moderate correlations with PFT measurements. For example, V4DCT(HU) defect volume increased significantly with decreasing FEV1/FVC (R=-0.65, P<.01). V4DCT in VSPECT defect regions was significantly lower than in nondefect regions (mean V4DCT(HU) 0.049 vs 0.076, P<.01). The average DSCs for the spatial overlap with SPECT ventilation defect regions were only moderate (V4DCT(HU)0.39 ± 0.11). Furthermore, ventral-to-dorsal gradients of V4DCT were strong (V4DCT(HU) R(2) = 0.69, P=.08), which was similar to VSPECT (R(2) = 0.96, P<.01).
An 18-patient study demonstrated significant correlations between 4D-CT ventilation and PFT measurements as well as SPECT ventilation, providing evidence toward the validation of 4D-CT ventilation imaging.
Mutations in the gene for the major protein component of peripheral nerve myelin, myelin protein zero (MPZ, P0), cause hereditary disorders of Schwann cell myelin such as Charcot‐Marie‐Tooth ...neuropathy type 1B (CMT1B), Dejerine‐Sottas syndrome (DSS), and congenital hypomyelinating neu‐ropathy (CHN). More recently, P0 mutations were identified in the axonal type of CMT neuropathy, CMT2, which is different from the demyelinating variants with respect to electroneurography and nerve pathology. We screened 49 patients with a clinical and histopathological diagnosis of CMT2 for mutations in the P0 gene. Three heterozygous single nucleotide changes were detected: two novel mis‐sense mutations, Asp61Gly and Tyr119Cys, and the known Thr124Met substitution, that has already been reported in several CMT patients from different European countries. Haplotype analysis for the P0 locus proved that our patients with the 124Met allele were not related to a cohort of patients with the same mutation, all of Belgian descent and all found to share a common ancestor (7).Our data suggest that P0 mutations account for a detectable proportion of CMT2 cases with virtually every patient harbouring a different mutation but recurrence of the Thr124Met amino acid substitution.The high frequency of this peculiar genotype in the European CMT population is presumably not only due to a founder effect but Thr124Met might constitute a mutation hotspot in the P0 gene as well.
A novel ventilation imaging method based on four-dimensional (4D) computed tomography (CT) has been applied to the field of radiation oncology. Understanding its reproducibility is a prerequisite for ...clinical applications. The purpose of this study was to quantify the reproducibility of 4D CT ventilation imaging over different days and the same session.
Two ventilation images were created from repeat 4D CT scans acquired over the average time frames of 15 days for 6 lung cancer patients and 5 minutes for another 6 patients. The reproducibility was quantified using the voxel-based Spearman rank correlation coefficients for all lung voxels and Dice similarity coefficients (DSC) for the spatial overlap of segmented high-, moderate-, and low-functional lung volumes. Furthermore, the relationship between the variation in abdominal motion range as a measure of the depth of breathing and variation in ventilation was evaluated using linear regression.
The voxel-based correlation between the two ventilation images was moderate on average (0.50 ± 0.15). The DSCs were also moderate for the high- (0.60 ± 0.08), moderate- (0.46 ± 0.06), and low-functional lung (0.58 ± 0.09). No patients demonstrated strong correlations. The relationship between the motion range variation and ventilation variation was found to be moderate and significant.
We investigated the reproducibility of 4D CT ventilation imaging over the time frames of 15 days and 5 minutes and found that it was only moderately reproducible. Respiratory variation during 4D CT scans was found to deteriorate the reproducibility. Improvement of 4D CT imaging is necessary to increase the reproducibility of 4D CT ventilation imaging.
In this publication, the influence of bond wire material properties (Au 2N/4N), and plasma pre-treatment on the wire-bond strength is investigated based on Automotive Electronics Council ...Qualification (AEC-Q100) and customer requirements. The wire pull force capability is compared, and growth of the Au/Al intermetallic phase (IMP) is analyzed with scanning electron microscope (SEM) cross sections after High Temperature Storage Life (HTSL, 150 °C), Temperature Cycling (TC, −65 °C – 150 °C) and unbiased Humidity Accelerated Stress Test (uHAST, 130 °C/85% relative humidity (RH)). The effect of plasma treatment prior bonding on 2N and 4N wires is discussed and compared to the results without plasma treatment prior wire bonding. Furthermore, test acceleration by using elevated test temperatures (HTSL, 250 °C) is shown and the wire capability compared.
Purpose: A novel lung ventilation imaging technique based on 4D‐CT can be used for functional avoidance to spare high‐functional lung regions, and early prediction or assessment of pulmonary toxicity ...in radiotherapy. However, there has been minimal validation showing inconsistent results in human subjects. The purpose of this study was to compare 4D‐CT ventilation images with SPECT ventilation images as clinical reference. Methods: In an IRB‐approved clinical trial, 4D‐CT ventilation and SPECT ventilation images were acquired in the supine position for 12 thoracic cancer patients. 4D‐CT ventilation was calculated by deformable image registration of 4D‐CT images, followed by analysis of the resultant displacement vector field to quantify regional volume change (Jacobian), a surrogate for ventilation. SPECT ventilation scans were performed by inhalation of 99mTc‐DTPA aerosols. We evaluated the physiologic accuracy of 4D‐CT ventilation by: (1) comparing 4D‐CT ventilation values in SPECT ventilation defect regions with those in non‐defect regions; (2) quantifying Dice similarity coefficients (DSCs) for the spatial overlap of low‐functional lung regions determined by 4D‐CT ventilation and SPECT ventilation; (3) comparing a ventral‐to‐dorsal gradient of 4D‐CT ventilation with that of SPECT ventilation. Results: Five patients showed severe depositions of SPECT DTPA aerosols in central airways, and hence were excluded from the analysis. The 4D‐CT ventilation value in SPECT ventilation defect regions was found to be significantly lower than that in non‐defect regions (0.14±0.06 vs. 0.19±0.07, p=0.01). The DSC for the spatial overlap of low‐functional lung regions was weak (0.29±0.11). 4D‐CT ventilation demonstrated a ventral‐to‐dorsal gravitational gradient, which was consistent with SPECT ventilation. Conclusion: A 12‐patient study demonstrated reasonable correlations between 4D‐CT ventilation and SPECT ventilation as clinical reference, indicating the potential for 4D‐CT ventilation imaging to achieve high physiologic accuracy. However, poor DSCs suggest the need for further studies to improve 4D‐CT ventilation imaging and/or a validation study design. National Lung Cancer Partnership Young Investigator Research Grant; NIH/NCI 2 R01 CA 093626
The female breast undergoes large scale deformations, when the patient position is changed from the prone position where imaging is usually performed to the supine position, which is the standard ...surgical setting. To guide the surgical procedure, MRI data need to be aligned between these two positions. Image registration techniques which are purely intensity based usually fail, when prone and supine image data are to be aligned. To address this we use patient specific biomechanical models to provide an initial deformation of the breast prior to registration. In contrast to previous methods, we use these models to estimate the zero-gravity reference state for both the prone and supine configurations and perform the subsequent registration in this space. In this symmetric approach we incorporate non-linear material models and displacement boundary conditions on the chest wall which lead to clinically useful accuracy in the simulation and subsequent registration.
Angiography confirmed the normal course of the left coronary artery with delayed retrograde visualisation of the right coronary artery via collaterals and run-off of the contrast medium into the ...pulmonary artery (bottom panel).
For the improvement of thrombolytic therapy with recombinant tissue-plasminogen activator (rt-PA) in children, more clinical data are needed. We retrospectively analyzed the clinical course of 20 ...patients (age ranging from 1 day to 16 years) with venous thrombosis (n = 16), arterial thrombosis (n = 2), and purpura fulminans by meningococcosis (n = 2). The venous thromboses were localized in the iliac-femoral veins (n = 9), brachiocephalic-jugular-subclavian veins (n = 6), and the superior caval vein (n = 1). The arterial occlusions were localized in the abdominal aorta and in the left pulmonary artery. Central venous catheters were of pathogenetic importance in seven cases. The patients were treated with rt-PA for 3 hours to 13 days. The dose ranged between 0.2 and 0.5 mg/kg for the initial bolus and 1.0 to 2.0 mg/kg/d for the continuous infusion. Nineteen patients received simultaneously low-dose unfractionated heparin. Complete clot lysis was detected in 11 cases, a partial lysis in 1, and in 8 patients thrombolytic therapy was not successful. An episode of hematemesis in one patient represented the only serious side effect observed in our study. A systemic decrease in fibrinogen concentration was also rare. In conclusion, thrombolysis with rt-PA represents an effective and safe therapy for children at the dosage used.
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