Haim  Azhari

Robert R. Edelman

David  Townsend

Multimodal Imaging and Hybrid Scanners

An important goal of software development in the medical field is the design of methods which are able to integrate information obtained from various imaging and nonimaging modalities into a cohesive framework in order to understand the results of qualitatively different measurements in a larger context. Moreover, it is essential to assess the various features of the data quantitatively so that relationships in anatomical and functional domains between complementing modalities can be expressed mathematically. This paper presents a clinically feasible software environment for the quantitative assessment of the relationship among biochemical functions as assessed by PET imaging and electrophysiological parameters derived from intracranial EEG. Based on the developed software tools, quantitative results obtained from individual modalities can be merged into a data structure allowing a consistent framework for advanced data mining techniques and 3D visualization. Moreover, an effort was made to derive quantitative variables (such as the spatial proximity index, SPI) characterizing the relationship between complementing modalities on a more generic level as a prerequisite for efficient data mining strategies. We describe the implementation of this software environment in twelve children (mean age <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>5.2</mml:mn><mml:mo>±</mml:mo><mml:mn>4.3</mml:mn></mml:mrow></mml:math> years) with medically intractable partial epilepsy who underwent both high-resolution structural MR and functional PET imaging. Our experiments demonstrate that our approach will lead to a better understanding of the mechanisms of epileptogenesis and might ultimately have an impact on treatment. Moreover, our software environment holds promise to be useful in many other neurological disorders, where integration of multimodality data is crucial for a better understanding of the underlying disease mechanisms.

Otto Muzik

Diane C. Chugani

Guangyu Zou

Jing Hua

Yi Lu

Shiyong Lu

Eishi Asano

Harry T. Chugani

Multimodality Data Integration in Epilepsy

Purpose: beyond the pure morphological visual representation, MR imaging offers the possibility to quantify parameters in the healthy, as well as, in pathologic lung parenchyma. Gas exchange is the primary function of the lung and the transport of oxygen plays a key role in pulmonary physiology and pathophysiology. The purpose of this review is to present a short overview of the relaxation mechanisms of the lung and the current technical concepts of T1 mapping and methods of oxygen enhanced MR imaging. Material and Methods: molecular oxygen has weak paramagnetic properties so that an increase in oxygen concentration results in shortening of the T1 relaxation time and thus to an increase of the signal intensity in T1 weighted images. A possible way to gain deeper insights into the relaxation mechanisms of the lung is the calculation of parameter Maps. T1 Maps based on a snapshot FLASH sequence obtained during the inhalation of various oxygen concentrations provide data for the creation of the so-called oxygen transfer function (OTF), assigning a measurement for local oxygen transfer. T1 weighted single shot TSE sequences also permit expression of the signal changing effects associated with the inhalation of pure oxygen. Results: the average of the mean T1 values over the entire lung in inspiration amounts to 1199 <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mo>/</mml:mo><mml:mo>−</mml:mo></mml:mrow></mml:mrow></mml:math> 117 milliseconds, the average of the mean T1 values in expiration was 1333 <mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mo>/</mml:mo><mml:mo>−</mml:mo></mml:mrow></mml:mrow></mml:math> 167 milliseconds. T1 Maps of patients with emphysema and lung fibrosis show fundamentally different behavior patterns. Oxygen enhanced MRT is able to demonstrate reduced diffusion capacity and diminished oxygen transport in patients with emphysema and cystic fibrosis. Discussion: results published in literature indicate that T1 mapping and oxygen enhanced MR imaging are promising new methods in functional imaging of the lung and when evaluated in conjunction with the pure morphological images can provide additional valuable information.

Alfred Stadler

Leopold Stiebellehner

Peter M. Jakob

Johannes F. T. Arnold

Edith Eisenhuber

Isabella von Katzler

Alexander A. Bankier

Quantitative and O2 Enhanced MRI of the Pathologic Lung: Findings in Emphysema, Fibrosis, and Cystic Fibrosis

Conformal radiotherapy (CRT) results in high-precision tumor volume irradiation. In fractioned radiotherapy (FRT), lesions are irradiated in several sessions so that healthy neighbouring tissues are better preserved than when treatment is carried out in one fraction. In the case of intracranial tumors, classical methods of patient positioning in the irradiation machine coordinate system are invasive and only allow for CRT in one irradiation session. This contribution presents a noninvasive positioning method representing a first step towards the combination of CRT and FRT. The 3D data used for the positioning is point clouds spread over the patient&#39;s head (CT-data usually acquired during treatment) and points distributed over the patient&#39;s face which are acquired with a structured light sensor fixed in the therapy room. The geometrical transformation linking the coordinate systems of the diagnosis device (CT-modality) and the 3D sensor of the therapy room (visible light modality) is obtained by registering the surfaces represented by the two 3D point sets. The geometrical relationship between the coordinate systems of the 3D sensor and the irradiation machine is given by a calibration of the sensor position in the therapy room. The global transformation, computed with the two previous transformations, is sufficient to predict the tumor position in the irradiation machine coordinate system with only the corresponding position in the CT-coordinate system. Results obtained for a phantom show that the mean positioning error of tumors on the treatment machine isocentre is 0.4 mm. Tests performed with human data proved that the registration algorithm is accurate (0.1 mm mean distance between homologous points) and robust even for facial expression changes.

R.  Posada

Ch.  Daul

D.  Wolf

P.  Aletti

Towards a Noninvasive Intracranial Tumor Irradiation Using 3D Optical Imaging and Multimodal Data Registration

Traditional mutual information (MI) function aligns two
multimodality images with intensity information, lacking spatial
information, so that it usually presents many local maxima that can
lead to inaccurate registration. Our paper proposes an algorithm of
adaptive combination of intensity and gradient field mutual
information (ACMI). Gradient code maps (GCM) are constructed by
coding gradient field information of corresponding original images.
The gradient field MI, calculated from GCMs, can provide
complementary properties to intensity MI. ACMI combines intensity MI
and gradient field MI with a nonlinear weight function, which can
automatically adjust the proportion between two types MI in
combination to improve registration. Experimental results
demonstrate that ACMI outperforms the traditional MI and it is much
less sensitive to reduced resolution or overlap of images.

Jiangang Liu

Jie Tian

Registration of Brain MRI/PET Images Based on Adaptive Combination of Intensity and Gradient Field Mutual Information

Objectives. SPECT/slow-rotation low-output CT systems can produce streak artifacts in filtered backprojection (FBP) attenuation maps, impacting attenuation correction (AC) in myocardial perfusion imaging. This paper presents an adaptive Bayesian iterative transmission reconstruction (ABITR) algorithm for more accurate AC. Methods. In each iteration, ABITR calculated a three-dimensional prior containing the pixels with attenuation coefficients similar to water, then used it to encourage these pixels to the water value. ABITR was tested with a cardiac phantom and 4 normal patients acquired by a GE Millennium VG/Hawkeye system. Results. FBP AC and ABITR AC produced similar phantom results. For the patients, streak artifacts were observed in the FBP and ordered-subsets expectation-maximization (OSEM) maps but not in the ABITR maps, and ABITR AC produced more uniform images than FBP AC and OSEM AC. Conclusion. ABITR can improve the quality of the attenuation map, producing more uniform images for normal studies.

Ji  Chen

Ernest V. Garcia

Russell D. Folks

Aharon  Peretz

James R. Galt

Adaptive Bayesian Iterative Transmission Reconstruction for Attenuation Correction in Myocardial Perfusion Imaging with SPECT/Slow-Rotation Low-Output CT Systems

Vibro-acoustography (VA) is a new imaging modality that has been applied to both medical and industrial imaging. Integrating unique diagnostic information of VA with other medical imaging is one of our research interests. In this work, we establish correspondence between the VA images and traditional X-ray mammogram by adopting a flexible control-point selection technique for image registration. A modified second-order polynomial, which simply leads to a scale/rotation/translation invariant registration, was used. The results of registration were used to spatially transform the breast VA images to map with the X-ray mammography with a registration error of less than 1.65 mm. The fused image is defined as a linear integration of the VA and X-ray images. Moreover, a color-based fusion technique was employed to integrate the images for better visualization of structural information.

H. Gholam Hosseini

A. Alizad

M. Fatemi

Integration of Vibro-Acoustography Imaging Modality with the Traditional Mammography

Purpose. To provide PET/CT image fusion with an improved PET resolution and better contrast ratios than standard reconstructions. Method. Using a super-resolution algorithm, several PET acquisitions were combined to
improve the resolution. In addition, functional PET data was smoothed with a hybrid
computed tomography algorithm (HCT), in which anatomical edge information taken from
the CT was employed to retain sharper edges. The combined HCT and super-resolution
technique were evaluated in phantom and patient studies using a clinical PET scanner.
Results. In the phantom studies, 3 mm<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mtext>F</mml:mtext><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>18</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>-FDG sources were resolved. PET contrast ratios
improved (average: 54<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>, range: 45<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>&#8211;69<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>) relative to the standard reconstructions. In the
patient study, target-to-background ratios also improved (average: 34<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>, range: 17<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>&#8211;47<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x0025;</mml:mi></mml:math>).
Given corresponding anatomical borders, sharper edges were depicted.
Conclusion. A new method incorporating super-resolution and HCT for 
fusing PET and CT images has been developed and shown to provide higher-resolution metabolic images.

John A. Kennedy

Ora  Israel

Alex  Frenkel

Rachel  Bar-Shalom

Improved Image Fusion in PET/CT Using Hybrid Image Reconstruction and Super-Resolution

The purpose of this article is to review the spectrum of image-based diagnostic tools used in the investigation of suspected deep vein thrombosis (DVT). Summary of the experience gained by the author as well as relevant publications, regarding vein imaging modalities taken from a computerized database, was reviewed. The imaging modalities reviewed include phlebography, color Doppler duplex ultrasonography (CDDUS), computerized tomography angiography (CTA) and venography (CTV), magnetic resonance venography (MRV), and radionuclide venography (RNV). CDDUS is recommended as the modality of choice for the diagnosis of DVT. A strategy combining clinical score and D-dimer test refines the selection of patients. Phlebography is reserved for discrepant noninvasive studies.

Diana Gaitini

Multimodality Imaging of the Peripheral Venous System

The purpose of the paper is to present and evaluate the performance of a new software-based registration system for patient setup verification, during radiotherapy, using electronic portal images. The estimation of setup errors, using the proposed system, can be accomplished by means of two alternate registration methods. (a) The portal image of the current fraction of the treatment is registered directly with the reference image (digitally reconstructed radiograph (DRR) or simulator image) using a modified manual technique. (b) The portal image of the current fraction of the treatment is registered with the portal image of the first fraction of the treatment (reference portal image) by applying a nearly automated technique based on self-organizing maps, whereas the reference portal has already been registered with a DRR or a simulator image. The proposed system was tested on phantom data and on data from six patients. The root mean square error (RMSE) of the setup estimates was <mml:math id="E1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.8</mml:mn><mml:mo>&#x00B1;</mml:mo><mml:mn>0.3</mml:mn></mml:mrow></mml:math> (mean value <mml:math id="E2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>&#x00B1;</mml:mo></mml:math> standard deviation) for the phantom data and <mml:math id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.3</mml:mn><mml:mo>&#x00B1;</mml:mo><mml:mn>0.3</mml:mn></mml:mrow></mml:math> for the patient data, respectively, by applying the two methodologies. Furthermore, statistical analysis by means of the Wilcoxon nonparametric signed test showed that the results that were obtained by the two methods did not differ significantly
 (<mml:math id="E4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>P</mml:mi></mml:math> value <mml:math id="E5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>&#x003E;</mml:mo><mml:mn>0.05</mml:mn></mml:mrow></mml:math>).

Pantelis A. Asvestas

Konstantinos K. Delibasis

Nikolaos A. Mouravliansky

George K. Matsopoulos

ESTERR-PRO: A Setup Verification Software System Using Electronic Portal Imaging

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International Journal of Biomedical Imaging

Multimodal Imaging and Hybrid Scanners

Multimodal Imaging and Hybrid Scanners

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