Current Medical Imaging Reviews

ISSN: 1573-4056

Current Medical Imaging Reviews
Volume 1, Number 1, January 2005

Contents

Role of Integrated 18-F FDG PET/CT in Recurrent Ovarian Cancer Pp.1-4
Sandro Sironi, Cristina Messa and Ferruccio Fazio
[Abstract] [Full text article]


Ultrasound Augmented Thrombolysis Pp.5-12
William C. Culp and Timothy C. McCowan
[Abstract] [Full text article]


The Cardiologist in the Periphery: Indications and Usefulness of Peripheral Artery Invasive Angiography in Patients Undergoing Coronary Angiography Pp.13-16
Gianluca Rigatelli, Massimo Giordan, Massimo Rinuncini, Laura Oliva, Beatrice Magro, Loris Ronoon and Giorgio Rigatelli
[Abstract] [Full text article]


Radionuclide Imaging in Patients with Ischemic Heart Failure Pp.17-23
Wanda Acampa, Mario Petretta, Laura Evangelista, Andrea Petretta and Alberto Cuocolo
[Abstract] [Full text article]


Tumor Specific Imaging Using Tc-99m and Ga-68 Labeled Radiopharmaceuticals Pp.25-34
David J. Yang, Ali Azhdarinia and E. Edmund Kim
[Abstract] [Full text article]


MRI Techniques for the Examination of Trabecular Bone Structure Pp.35-41
M. Petrantonaki, T. Maris and J. Damilakis
[Abstract] [Full text article]


Magnetic Resonance Imaging of Iron in Parkinson's Disease Pp.43-48
Kazuo Abe and Tachio Hikita
[Abstract] [Full text article]


Geometric Distortion in Structural Magnetic Resonance Imaging Pp.49-60
Deming Wang and David M. Doddrell
[Abstract] [Full text article]


Imaging Primary Brain Tumors by Single-Photon Emission Computerized Tomography (SPECT) with Technetium-99m Sestamibi (MIBI) and Tetrofosmin Pp.61-66
Luca Filippi, Riccardo Santoni, Carlo Manni, Roberta Danieli, Roberto Floris and Orazio Schillaci
[Abstract] [Full text article]


Quantitative Ultrasound in Diagnosis of Metabolic Bone Diseases Pp.67-74
Bogna Drozdzowska and Wojciech Pluskiewicz
[Abstract] [Full text article]


Ultrasonography for Rhinoplasty Pp.75-80
Eray Copcu
[Abstract] [Full text article]


Analysis of Functional Brain Images Using Population-Based Probabilistic
Atlas Pp.81-87
Jae Sung Lee and Dong Soo Lee
[Abstract] [Full text article]


Noninvasive Imaging and Monitoring of Retinal Pigment Epithelium Patterns Using Fundus Autofluorescence – Review Pp.89-103
Carsten Framme, Johann Roider, Helmut G Sachs, Ralf Brinkmann and Veit-Peter Gabe
[Abstract] [Full text article]




Abstracts

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Role of Integrated 18-F FDG PET/CT in Recurrent Ovarian Cancer
Sandro Sironi, Cristina Messa and Ferruccio Fazio
[Full text article]

Carcinoma of the ovary is the third most common cancer of the female genital tract but it accounts for over half of all deaths related to gynecologic neoplasms. This is primarily because, unlike patients with other common malignant gynecologic tumors, most patients with ovarian cancer have advanced stage of disease at the time of initial diagnosis. After completion of initial surgery, patients with ovarian cancer receive systemic chemotherapy for disease control. Despite the fact that ovarian cancer is very sensitive to platinum-based chemotherapy, 5-year survival for patients with advanced disease is only 17%, due to the high rate of recurrent disease. Although its limited accuracy, serial determination of the tumor marker CA 125 is the most frequently used method for monitoring the disease. Morphologic imaging modalities have played a major role to accurately delineate disease status. Computed tomography (CT) proved to be useful for evaluating response to treatment in these patients. Fluorodeoxyglucose (FDG) positron emission tomography (PET), which provides metabolic information useful in the identification of cancer tissue, also proved to be of value for the assessment of recurrent ovarian cancer. Recently, a new imaging technique combining state of the art PET and CT equipments (integrated PET/CT) has been introduced in clinical use. PET/CT device acquires PET and CT images, that are contemporaneous and coregistered, to localize elevated FDG uptake with improved anatomic specificity. Potential advantages of PET/CT include increased lesion conspicuity, anatomic localization of lesions, and differentiation of neoplastic disease process from postreatment fibrosis. In this article we illustrate the role of PET/CT relative to CT and MR imaging in the field of recurrent ovarian cancer.


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Ultrasound Augmented Thrombolysis
William C. Culp and Timothy C. McCowan
[Full text article]

Recent developments in thrombolysis include transcutaneous ultrasound augmentation of tissue plasminogen activator (tPA) activity and microbubble augmented ultrasound lysis. While standard thrombolytic drugs are well-known, the increased thrombolytic drug activity with the addition of ultrasound is a new clinical tool early in development. The therapeutic thrombolytic action of ultrasonographic microbubble contrast agents and a beam of ultrasound when in contact with clot is also a technique rapidly developing and not widely appreciated. Both augmentation techniques have progressed to early clinical use. The use of directed ultrasound beams to increase lytic activity in a specific target with either technique may lead to fewer hemorrhagic complications, especially in anatomical areas remote from the target. The combination of intravenous tPA and directed ultrasound is very promising in the treatment of ischemic stroke in human trials, and microbubble augmented ultrasound thrombolysis has been proven effective in several animal models of stroke and clotted dialysis grafts, with phase I/II trials in human dialysis grafts, arteries, and veins ongoing. This paper will review the state-of-the-art in this rapidly progressing field.


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The Cardiologist in the Periphery: Indications and Usefulness of Peripheral Artery Invasive Angiography in Patients Undergoing Coronary Angiography
Gianluca Rigatelli, Massimo Giordan, Massimo Rinuncini, Laura Oliva, Beatrice Magro, Loris Ronoon and Giorgio Rigatelli
[Full text article]

Although the most widely used screening techniques for extra-cardiac atherosclerotic distributions are noninvasive, in selected patients undergoing coronary arteriography a coincident angiography of certain peripheral arteries may appear justified. Subclavian artery angiography may be indicated in patients undergoing coronary angiography and candidates to internal mammary artery by pass surgery in order to prevent any subclavian coronary steal syndrome after coronary surgery using arterial conduits: in the authors experience should be always performed in patients with multiple risk factors and multivessel coronary artery disease. An extensive literature supports the need of a renal artery angiography in patients with unexplained renal dysfunction, flash pulmonary edema, and severe hypertension. Renal angiography in patients undergoing coronary angiography is diagnostic of unknown renal artery stenosis in 11% to 18% of patients, the prevalence of unsuspected renal artery stenosis increasing from 7% to 22% in patients with coronary artery disease. Aortoiliac lesions are detected in 40.5% of patients undergoing coronary angiography and in a significant proportion of patients with aortic aneurismal disease by a simple 35-40 ml injection of contrast medium at level of L1. Data given by an abdominal aorta angiography may be important for choose the correct treatment strategy in case of abdominal aorta aneurysms or renal artery stenosis especially in patients candidates to coronary bypass surgery and generally in emergent or urgent clinical setting.

Invasive angiography of peripheral arteries performed by the cardiologist at the time of coronary angiography appears justified following clear criteria in patients over 60 years, multi-vessel CAD and multiple risk factors especially if candidates to cardiac surgery in order to detect potentially dangerous peripheral artery disease and to improve long-term results of myocardial revascularization or other cardiac surgical procedures.


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Radionuclide Imaging in Patients with Ischemic Heart Failure
Wanda Acampa, Mario Petretta, Laura Evangelista, Andrea Petretta and Alberto Cuocolo
[Full text article]

Nuclear imaging procedures are well-established diagnostic tools in clinical cardiology, providing noninvasive information about myocardial perfusion, cardiac function and metabolism. Scintigraphic parameters provide relevant information that aids in everyday clinical decision making for referring physicians. In patients with coronary artery disease, the presence of myocardial necrosis, postischemic stunning and hibernation can determine left ventricular dysfunction leading to ischemic heart failure. The prognosis of these patients is still poor and the long-term results of medical management remain discouraging. It is now well established that ventricular dysfunction is often a reversible process and ventricular function may improve following myocardial revascularization. Patients with extensive areas of hibernation treated medically have a worse prognosis as compared to those who undergo revascularization with a similar extent of viable myocardium. Therefore, an accurate non-invasive assessment of myocardial viability with the preoperative differentiation between hibernation and stunning and irreversibly necrotic tissue is important for clinical decision-making to select patients candidates for revascularization. Radionuclide imaging techniques evaluating myocardial perfusion, cell membrane integrity, ventricular function and cardiac metabolism have demonstrated clinical utility in the assessment of myocardial viability and in predicting improvement of ventricular function and prognosis after coronary revascularization.


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Tumor Specific Imaging Using Tc-99m and Ga-68 Labeled Radiopharmaceuticals
David J. Yang, Ali Azhdarinia and E. Edmund Kim
[Full text article]

Improvement of scintigraphic tumor imaging is extensively determined by the development of more tumor specific radiopharmaceuticals. Thus, to improve the differential diagnosis, prognosis, planning and monitoring of cancer treatment, several functional pharmaceuticals have been developed. Application of molecular targets for cancer imaging, therapy and prevention using generator-produced isotopes are the major focus of ongoing research projects. Radionuclide imaging modalities (positron emission tomography, PET; single photon emission computed tomography, SPECT) are diagnostic cross-sectional imaging techniques that map the location and concentration of radionuclide-labeled radiotracers. ^99mTc- and ⁶⁸Ga-labeled agents using ethylenedicysteine (EC) as a chelator were synthesized and their potential uses to assess tumor targets were evaluated. ^99mTc (t_1/2=6 hr, 140 keV) is used for SPECT and ⁶⁸Ga (tt_1/2=68 min, 511 keV) is for PET. Molecular targets labeled with Tc-99m and Ga-68 can be utilized for prediction of therapeutic response, monitoring tumor response to treatment and differential diagnosis. Molecular targets for oncological research in (1) cell apoptosis, (2) gene and nucleic acid-based approach, (3) angiogenesis (4) tumor hypoxia, and (5) metabolic imaging are discussed. Numerous imaging ligands in these categories have been developed and evaluated in animals and humans. Molecular targets were imaged and their potential to redirect optimal cancer diagnosis and therapeutics were demonstrated.


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MRI Techniques for the Examination of Trabecular Bone Structure
M. Petrantonaki, T. Maris and J. Damilakis
[Full text article]

It is well known that bone mineral density measurement is a widely available means of identifying individuals with osteoporosis. However, bone strength depends not only on the amount of material but also on properties related to bone quality. Significant progress has been made in the development of magnetic resonance imaging (MRI) techniques for assessing bone status during the past years. This review discusses the technical principles, clinical applications, recent advances, limitations, and future trends of MRI techniques available for the diagnosis of osteoporosis. Using MRI, bone status can be evaluated either by T2* measurements, which are sensitive to field inhomogeneities caused by susceptibility differences at the marrowbone interfaces, or by high-resolution imaging. In T2* relaxometry, the decrease in marrow T2* measurements and its decay characteristics provide useful information about the structure and quality of the trabecular bone. T2* measurements have been performed at several locations of the axial and peripheral skeleton such as spine, proximal femur and calcaneus. It has also been shown that osteoporotic and normal subjects may be distinguished using T2* decay characteristics. In addition to T2* relaxometry, high-resolution MR imaging may be used to quantify trabecular bone architecture. Gradient echo and spin echo sequences have been used to obtain images in vitro and in vivo mainly at peripheral sites of the skeleton. Several image-processing methods have been applied to measure bone structure. Technological advances in MRI scanners offer exciting new possibilities in bone analysis and may contribute to our understanding of osteoporosis.


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Magnetic Resonance Imaging of Iron in Parkinson's Disease
Kazuo Abe and Tachio Hikita
[Full text article]

The primary pathology of idiopathic Parkinson's disease (PD) is degeneration of the substantia nigra pars compacta. This leads to a reduction in striatal dopamine, which results in the cardinal symptoms of bradykinesia, tremor and rigidity. Increased iron content is consistently reported post-mortem in the substantia nigra of patients with PD and reactive microglia and its capacity to enhance production of toxic reactive oxygen radicals. This may suggest that ironrelated oxidative stress may be an important component of the neurodegenerative process in such patients. Presently the mechanisms involved in the disturbances of iron metabolism in PD remain obscure, but evaluating iron contents in brain of PD may be important.

Evaluation of iron contents in brain has been possible only with post-mortem study, but advent of MRI techniques makes it possible to evaluate brain iron deposits in vivo. However, previous studies have been inconsistent with the findings compared with post-mortem investigations. This suggests that improved MRI techniques may be useful for assessing brain iron deposits with greater accuracy.

In this mini-review, we discussed investigations for assessing brain iron in PD.


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Geometric Distortion in Structural Magnetic Resonance Imaging
Deming Wang and David M. Doddrell
[Full text article]

Geometric distortion, an undesirable image artifact, is an inferior aspect associated with magnetic resonance imaging (MRI). Although slight distortions in MR images often have no consequences in reaching clinical conclusions, geometric distortions can make significant differences in certain MR applications such as, for example, stereotactic localization in radio-surgery and MR image-guided biopsy. In this article, geometric distortion in structural MRI is reviewed. It begins with a brief discussion of various sources that can cause geometric distortion in structural MRI, followed by a review of the apparatus and methods that have been developed for the measurement and characterization of the geometric distortion in MRI. The paper will then focus on a novel phantom-based technique that has been developed recently by the authors. This technique can provide a comprehensive and complete measurement of the geometric distortion in 3-dimensions with unprecedented details and accuracy. The major outcomes of a comprehensive study on the geometric distortion in representative clinical MR scanners, carried out recently using this technique, will be discussed. The article will also include a discussion of various correction methods that have been developed for correcting geometric distortion in MRI.


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Imaging Primary Brain Tumors by Single-Photon Emission Computerized Tomography (SPECT) with Technetium-99m Sestamibi (MIBI) and Tetrofosmin
Luca Filippi, Riccardo Santoni, Carlo Manni, Roberta Danieli, Roberto Floris and Orazio Schillaci
[Full text article]

In spite of many advances in diagnosis and therapy, primary brain tumors remain a serious challenge for clinicians. In particular, high-grade gliomas are characteristically radioresistant and their localization and invasive growth pattern often reduce the effectiveness of surgery. MRI and CT scan proved powerful tool to diagnose primary brain tumors. Nevertheless, these methods have some limitations, especially after surgery and radiochemotherapy, in discriminating between residual neoplasia versus radionecrosis / scar tissue. Scintigraphy by MIBI and Tetrofosmin, successfully used as imaging agents in oncology (i.e. breast and lung cancer), was also applied in diagnosis and follow-up of brain tumors. These two radiotracers are synthetic lipophilic cationic complexes and their uptake and retention depend on perfusion and cellular metabolism so that the level of radiotracer uptake corresponds to the cellular activity of the tumor. Although these two radiopharmaceuticals present similar imaging properties, very few studies in brain tumors imaging were performed with Tetrofosmin. On the contrary, MIBI was widely proved useful in diagnosis of brain tumors, showing high specificity and sensitivity. A trend between MIBI uptake and gliomas grade was observed, while this relationship is not present in glioblastomas, which exhibit a variable uptake. Most important, MIBI was demonstrated effective in patients’ follow-up after treatments, well differentiating tumoral viable tissue versus radionecrosis. Since MIBI and Tetrofosmin are physiologically taken by intracranial structures like choroid plexus, the detection of small tumoral lesion in para-ventricular areas, especially in case of recurrence, may be problematic. In such cases, the dual integrated modality imaging system SPECT/CT might be considered of value to obtain a precise anatomical localization and to exclude the presence of disease in sites of physiologic tracer accumulation.


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Quantitative Ultrasound in Diagnosis of Metabolic Bone Diseases
Bogna Drozdzowska and Wojciech Pluskiewicz
[Full text article]

Currently, the diagnosis of osteoporosis is based on bone mineral density measurements using Dual Energy Xray Absorptiometry (DXA). DXA provides information about quantitative content of calcium hydroxyapatite in the skeleton. From about 20 years Quantitative Ultrasound (QUS) measurements are used. QUS reveals both quantitative and qualitative (elasticity and microstructure) features of bone tissue and was used in several pathologic and physiologic conditions.

The most important are results of prospective studies showing the ability of QUS measurements to predict osteoporotic fractures. QUS was used in monitoring skeletal changes during therapy on osteoporosis. In several studied QUS measurements showed an ability to detect skeletal changes in children and adolescents and involutional changes at the skeleton. QUS measurements were also used in order to follow bone changes during pregnancy and lactation, glucocorticosteroid therapy, renal osteodystrophy, oncologic and rheumatic diseases, and prolonged immobilization.

Advantages of QUS are: lack of ionizing radiation, portability of devices and their relatively low cost. Disadvantages of QUS include the lack of precise determination of measured bone features, measurements limited to peripheral skeleton, relatively poor precision and the lack of unification of several devices.

Currently, despite these limitations QUS is a validated method in diagnostic armentarium in metabolic bone diseases.


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Ultrasonography for Rhinoplasty
Eray Copcu
[Full text article]

Objective: To get the desired outcome and minimize the complications in rhinoplasty it is essential that the anatomy of the nose be precisely known and an appropriate surgical technique should be chosen for the existing problem in a given patient. Preoperative assessment in rhinoplasty is usually based on a physical examination and photographs of the patient. To date, there has been no objective diagnostic test for nose anomalies such as bulbous nasal tip.

Methods: In this study we measured the interdomal distance and size of the interdomal fat pad using USG in a total of 40 rhinoplasty patients. Open rhinoplasty was performed in all patients. Also, interdomal fat pad was dissected and excised in all patients. The size of the specimens was determined and their histopathological diagnoses were made. All the cases were evaluated in the 6th month after the operations. Reviewing of the literature was performed.

Results: Before the operation, six patients had been diagnosed as bulbous nasal tip clinically. In the patients with bulbous nose both interdomal distance and interdomal fat pad proportions were found to be larger than normal. In the cases in which tip refinement had been performed the interdomal distance was measured as zero.

Conclusions: Joseph in 1931 used the “profilometer”; Webster et al. in 1977 used the projectometer in the evaluation of the nose. The evaluation of the anatomical structure of the nose has been the topic of many anthropometric studies and advanced and highly detailed studies with 3 dimensional facial plaster models; digitizer or laser surface scanners have appeared the literature. Tasman and Helbig used the ultrasonography in the evaluation of the nasal tip area. Evaluation of the interdomal space by using USG is quite simple, cheap and easily applicable. In addition, interdomal fat pad can be visualized and an objective criterion can be obtained for bulbous nose by measuring the interdomal distance on USG. Since the excision of interdomal fat pad could only be achieved by open rhinoplasty, and that tip refinement is required in order to correct the increased interdomal distance, pre-operative interdomal USG will guide the surgeon and provide objective criteria in determination of the operative technique in bulbous nose. This is the first study to show interdomal fat pad by a diagnostic test and it can be concluded that interdomal fat pad excision is necessary for the prevention of supratip.


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Analysis of Functional Brain Images Using Population-Based Probabilistic Atlas
Jae Sung Lee and Dong Soo Lee
[Full text article]

Advances in imaging technology in the past decades have allowed profound insights into the human brain function and anatomy for normal and pathological conditions. Population-based probabilistic atlases (probabilistic map) for structural and functional anatomy of the brain have been developed using MRI, SPECT, and cytoarchitectonic data and provide a standard framework for functional brain data analysis. For example, automated delineation of the volume of interest (VOI) using the probabilistic maps of individual brain structures predefined on standard templates provides an efficient way for the objective assessment of image intensity and the underlying physiologies reflected by that image intensity. This review will focus on the development of the population-based atlases and application studies proving the utility of the atlases in basic neuroscience and the clinical assessment of brain disorders.


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Noninvasive Imaging and Monitoring of Retinal Pigment Epithelium Patterns Using Fundus Autofluorescence - Review
Carsten Framme, Johann Roider, Helmut G Sachs, Ralf Brinkmann and Veit-Peter Gabe
[Full text article]

Non-invasive imaging of the retinal pigment epithelium (RPE) using autofluorescence became recently available with the introduction of confocal laser scanning ophthalmoscopes. Fundus autofluorescence is usually excited at a wavelength of 488nm and the emitted light is detected above 500nm. This intrinsic autofluorescence was shown to derive from the lipofuscin accumulating within the RPE either with age or also due to different hereditary or degenerative diseases of the macula as e.g. age-related macular degeneration. Since a variety of macular diseases correlate with distinct RPE changes, specific patterns of autofluorescence could be evaluated within the recent years for diagnostic and prognostic reasons in those RPE-related diseases. Moreover autofluorescence can also be regarded as a monitoring tool after therapeutic applications as macular surgery or laser treatment. Other new applications try to determine macular pigment density using autofluorescence or use it to evaluate oxygen-dependent cell metabolism. This review summarizes the recent findings of autofluorescent patterns in specific diseases and therapeutic approaches and emphasizes on the tremendous potential of this novel imaging method.