Dear subscribers, Together with this December issue of Acta Radi- ologica, you will find a unique publication: Acta Radiologica 19212006. Our radiological journal is now quite a ''grand old lady,'' founded back in 1921, a substantial number of years ago. It is not, however, the oldest, an accolade which probably belongs to Archives of Clinical Skiagraphy, later renamed the British Journal of Radiology, founded as early as April 1896, just a few months after Wilhelm Conrad Rontgen's discovery of the so- called X-ray. In this special issue of Acta Radiologica, written and edited by Professor Emeritus Anders Hem- mingsson, a former Editor in Chief of the journal, you will find an overview of the most important milestones of the first 85 years of Acta Radiologica. You will also find one prominent article from every decade since its foundation in 1921. Each of those articles represent milestones not only within Nordic radiology, but internationally as well, the first of which is Hugo Laurell's article from 1925, ''Freie Gas in der Bauhohle,'' followed by Peter Rusthoi's ''Uber Angiographie'' from 1933, Stig Radner's ''An Attempt at the Roentgenologic Visualization of Coronary Blood Vessels in Man'' from 1945, Sven Ivar Seldinger's world-famous article from 1953, ''Catheter Replacement of the Needle in Percuta- neous Arteriography,'' and, not least, Torsten Al- men's article from 1973, ''The Effect of Non-ionic
GÖSTA FORSSELL, professeur du röntgendiagnostic à l’Institut médico-chirurgical Carolin à Stockholm, accomplit ses 65 ans le 2 mars 1941 et quittera de ce fait ses fonctions de professeur à l’université. La part prise par GÖSTA FORSSELL dans les progrès de la radiologie médicale est bien connue de tous les lecteurs des Acta Radiologica. La contribution que GÖSTA FORSSELL a apportée à la radiologie ne peut encore être considérée dans son entier, puisque, à la veille de ses 65 ans, se trouvant encore à l’apogée de ses facultés d’homme de sciences et d’organisateur, il s’occupe actuellement à la mise au point de sa mémorable découverte de l’autoplasie de la muqueuse dans l’appareil digestif. Puisse-t-il lui être permis de poursuivre dans la plénitude de ses forces l’oeuvre scientifique de sa vie et, pendant longtemps encore, de consacrer ses efforts à la prospérité et à l’avenir de la radiologie médicale. Lorsqu’en 1926 GÖSTA FORSSELL célébra son cinquantenaire, il fut grandiosement fêté par ses amis et ses disciples. 120 radiologistes de 13 pays différents ont résumé les expériences qu’ils avaient réalisées dans les domaines des recherches de la radiologie médicale dans une publication jubilaire qui lui fut consacrée, Xenia Forsselliana, pars I et II, formant les tomes VI et VII des Acta Radiologica. Aujourd’hui, de néfastes circonstances extérieures ne permettent pas aux nombreux amis de GÖSTA FORSSELL, dans tous les pays, de se réunir et de lui rendre l’hommage qui lui est si légitimement dû. Les élèves et amis travaillant maintenant dans les institutions scientifiques qu’il a créées, les services de röntgen de l’Hôpital des Séraphins et de l’Hôpital Carolin ainsi que le Radiumhemmet avec ses services de recherches, ont cependant voulu célébrer son activité de savant en éditant la pars III de Xenia Forsselliana, qui, formant les fascicules 1 et 2, tome XXII, des Acta Radiologica, expose les résultats obtenus par ces institutions au cours de leurs différentes recherches pendant les dernières années.
Dear subscribers, Together with this December issue of Acta Radi- ologica, you will find a unique publication: Acta Radiologica 19212006. Our radiological journal is now quite a ''grand old lady,'' founded back in 1921, a substantial number of years ago. It is not, however, the oldest, an accolade which probably belongs to Archives of Clinical Skiagraphy, later renamed the British Journal of Radiology, founded as early as April 1896, just a few months after Wilhelm Conrad Rontgen's discovery of the so- called X-ray. In this special issue of Acta Radiologica, written and edited by Professor Emeritus Anders Hem- mingsson, a former Editor in Chief of the journal, you will find an overview of the most important milestones of the first 85 years of Acta Radiologica. You will also find one prominent article from every decade since its foundation in 1921. Each of those articles represent milestones not only within Nordic radiology, but internationally as well, the first of which is Hugo Laurell's article from 1925, ''Freie Gas in der Bauhohle,'' followed by Peter Rusthoi's ''Uber Angiographie'' from 1933, Stig Radner's ''An Attempt at the Roentgenologic Visualization of Coronary Blood Vessels in Man'' from 1945, Sven Ivar Seldinger's world-famous article from 1953, ''Catheter Replacement of the Needle in Percuta- neous Arteriography,'' and, not least, Torsten Al- men's article from 1973, ''The Effect of Non-ionic
Acta Radiologica has now been published for 85 years, and especially during the last decades discussions about the survival of a high number of scientific journals have taken place. Despite most of the journals are accessible electronically they seem to survive also as paper issues. With time old documents have a tendency to disappear. Although several reviews have been written about Acta Radiologica since it started in 1921, we decided to review the existing material about the journal. A short survey of a few other radiological journals with a long history is also included. It has been the opinion among Scandinavian radiologists that Acta Radiologica was one of the first radiological scientific journals. This is not quite correct, as evident from the following.
Als Prof. LON) DE CARVALHO Ende Mai 1932 meinem Chef, Prof. H. C. JACOBAEUS, zwei Angiopneumogramme sandte, boten diese mil' u. a. den Anlass, das Thema und die Versuche mit 'I'ieren Zll disponieren, deren praliminare Resultate hier dargelegt werden sollen. Die praktische Arbeit konntc erst im November hegonnen werden. Die Experimente beabsichtigten, zunachst die Koronargefasse, besenders die Arterien, riintgenologiseh darzustellen. Analog u. a. den friiheren pulmonalen Angiographicversuchen teils durch direkte Punktion z. B. des rechtcn Vorhofes unci Injektion eines Kontrastrnittels, teils durch Sondierung del' Vorkammer nach FORSS~IANN -galt es die ::VHiglichkeiten fiir cine Puuktion bzw. Sondierung zu untersuchen. Ich habe darum die Miigliehkeiten mit Versuchen ali Tieren in vivo in Betraeht gezogen: einerseits dircktc Punktion des Bulbus aortae, andercrseits Sondier'ung desselben von einer peripheren Arterie aus, naeh Inzision derselben sowie durch Punktion mit Spezialtroikart. Wir haben den Bulbus aortae im allgemeinen von del' Arteria carotis communis dextra aus mit eincm Ureterkatheter sondiert, so dass sich die Rpitze unmittelbar oberhalh del' Aortenklappen befindet. Beim Kaninchen z. B. ist die Sondierung leieht auszufiihren. Nimmt man cine stumpfe zylindrisehe Sonde von geeignetem Kaliber, so passiert sie durch das Aortenostium in die linke Herzkarnmer hinein, ohne die Aortenklappen zu beschadigen. Da bei den Experimenten die physiologischen Vcrhaltnisse m6glichst gcwahrt bleihen sollten, war namlich das Arretiercn del' Sondenspitze in einer Klappentasche zu vermeiden. Die
When GÖSTA FORSSELL, pioneer and organizer, scientist and teacher, healer and lover of mankind, passed away on Monday, the 13th of November, after several months of increasing heart failure Sweden lost one of the most noble of Her sons. His figure as a leader, his innate living strength and his indefatigable energy were, no doubt, inheritances from the generations of Dalecarlian and Helsingland farmers, warriors and clergy authoritative and resolute forefathers from which he could trace his descent right back from the sixteenth century. FORSSELL’S richly facetted personality, his burning bent on research and marked scientific powers, his constructive imagination as well as his organizing capabilities were probably those qualities which caused him, whilst still in his years of study, to throw himself into an entirely new branch of medicine radiology which the discoveries of roentgen and radium rays had created. His powers of bold intuition enabled him to realize the enormous developmental possibilities of this science and its future importance for medicine. As a young medical student he served his apprenticeship under the first roentgen pioneer in Sweden, THOR STENBECK. About this time (1899) he took part in the first curative treatment in the world of a case of cancer of the skin. One hundred and fifty treatments extending over some nine months were required in all for the cure. The patient was demonstrated nearly 30 years later free from symptoms at the second International Congress of Radiology in Stockholm. One may perhaps best appreciate the progress of development when I state that a similar case in these days would be cleared up by a single treatment lasting but a minute. The outlines of FORSSELL’S radiological activities are as follows.Assistant in theRoentgenDepartment of the University Hospital of Upsala, 1902 Head of the Roentgen Institute of the Serafimerlasarettet 1906 1941. Director of the »Radiumhemet» (Radium Home) 191
Acta Radiologica was founded by Gösta Forssell in 1921 in collaboration with the Danish, Finnish, Norwegian and Swedish Radiologic Societies. Gösta Forssell wrote in his first editorial in 1921 that ‘‘by joint work and joint economic responsibility the journal has the support of all the radiologists of the North’’. This has been true for the last seven decades and during this time Acta Radiologica has been one of the world’s leading radiologic journals. Gösta Forssell died in 1950 and his place as editor was taken for a short period by Elis Berven. He was followed by Erik Lindgren, under whose eminent guidance (1951 to 1983) Acta Radiologica maintained its leading position. For the last decade, Erik Boijsen (1983 1992) has been chief editor of Acta Radiologica and throughout this period he has succeeded in preserving the strengths and traditions of the journal. When Erik Boijsen became chief editor of Acta Radiologica in 1983, he had been well prepared for the role by his leadership of the Lund School of Radiology. In Lund, he had been involved in research in, e.g., angiography and cardiology. Later, as chairman of the radiologic institutions in Malmö and Lund, he had helped to make both centers pre-eminent in Nordic radiology, as evidenced by the numerous foreign scientists who trained there during this time. His interest in the analysis of modern radiologic techniques, both for the county health authorities and for the central government, has since been reflected in the content of Acta Radiologica. One of the greatest achievements of Erik Boijsen, as chief editor of Acta Radiologica, was the separation of the Foundation of Acta Radiologica and Acta Oncologica in 1987. Since its inception in 1921, Acta Radiologica had covered the whole field of diagnostic radiology, radiation therapy and radiophysics, but in 1963 Acta Radiologica Diagnosis and Acta Radiologica Oncology were separated into two parallel journals. Rapid developments in both radiology and oncology necessitated similar changes and division of the Foundation of Acta Radiologica became inevitable. A happy divorce was accomplished in 1986 under the pragmatic leadership of Erik Boijsen and Lars-Gunnar Larsson and this has been of benefit to both Acta Radiologica and Acta Oncologica. At that time the subtitle ‘‘Diagnosis’’ was dropped from the journal’s title as, in the words of Erik Boijsen, it ‘‘will be reporting on research in diagnosis and interventional radiology based on all forms of imaging techniques’’. This is in accordance with the statement by Erik Lindgren in 1980 that ‘‘new methods introduced, such as ultrasound, scintigraphy, computed tomography and possibly still others such as magnetic resonance will appear (in Acta Radiologica) in the future. Acta Radiologica holds most emphatically that all imaging techniques should be concentrated in the radiology departments where the basic skills are centered’’. The introduction of an independent review system during the 1980s has enhanced the international reputation of the journal. The engagement of editors from Denmark, Finland and Norway has also strengthened the journal and is an indication of the commitment made by Erik Boijsen that Acta Radiologica should be a journal primarily for the Nordic countries. On the other hand, Erik Boijsen’s international contacts and farsightedness havemeant that the journal enjoys worldwide support both in terms of the articles published and journal subscriptions. The free distribution of journal supplements to all subscribers is another great achievement during the last year. This means that summaries of dissertations in radiology will reach a broader readership throughout the scientific community. Nordic radiologists are grateful to Erik Boijsen for his efforts and his success in maintaining the position of Acta Radiologica as a leading journal in its field. His pragmatic and realistic leadership has been a great strength for Acta Radiologica during the last decade. Anders Hemmingsson
UNLABELLED:The main objective of this thesis was to evaluate and monitor the morphological response following treatment interventions in patients with chronic Achilles tendinopathy by using different MRI techniques. For this purpose, we investigated different types of sequences, including gadolinium contrast medium-enhanced T1-WI images (CME T1-WI), and developed a precise method to measure tendon volume and mean intratendinous signal of the Achilles tendon. Study I aimed at evaluating 15 patients with chronic, painful Achilles tendinosis, before and 2 years after surgical treatment. There was marked regression of the intratendinous signal postoperatively. The most sensitive sequence for depicting an intratendinous lesion in this study was CME T1-WI images. They showed a regression of the intratendinous signal abnormality from 13/15 patients preoperatively to 4/15 postoperatively. The clinical outcome was excellent in eight, good in five, fair in one and poor in one patient. In study II, the early contrast agent enhancement in the dynamically enhanced MRI signal (DEMRI) was correlated with the histopathologic findings in 15 patients with chronic Achilles tendinopathy. Early contrast enhancement (within the first 72s) was seen in DEMRI in the symptomatic Achilles tendons, with a significant difference compared to the asymptomatic contralateral tendons. Increased severity of tendon changes, including fiber structure abnormality, increased vascularity, rounding of nuclei, and increased amount of glycosaminoglycans, correlated to CME. In study III, we developed a computerized 3-D seed-growing MRI technique to measure tendon volume and mean intratendinous signal. This technique showed an excellent inter- and intra-observer reliability. The technique was also used to follow up prospectively the tendon adaptation and healing described in studies IV-VI. In study IV, using serial MRI during a period of 1 year, we evaluated the biological effect of tendon repair following iatrogenic tendon injury by five transversal ultrasound-guided core biopsies employing a needle technique in chronic Achilles tendinopathy. Alterations found during healing, such as tendon volume and intratendinous reactive changes, could be monitored by MR imaging, and subsided as noted in the 7- and 12-month follow-ups. In study V, we evaluated the effect of treatment with a 3-month, daily performed, heavy-loaded calf-muscle strength training program in 25 patients who had been suffering from chronic, painful Achilles tendinopathy. Tendon volume decreased by 14%, and the mean intratendinous signal by 23%. The clinical outcome was improved. In study VI, we revealed tendon adaptation immediately following calf-muscle strength training. An MRI examination within 30min of the performed exercises resulted in increased total tendon volume (12%) and mean intratendinous signal (31%).CONCLUSION:MRI techniques can be used as an adjunct to clinical evaluation by monitoring morphological effects following different treatment interventions, thereby adding evidence in clinical studies on patients with chronic Achilles tendinopathy.
Cochlear implantation is a treatment for patients with severe sensorineural hearing loss/deafness, who get no help from ordinary hearing aids. The cochlear implant is surgically placed under the skin near the ear and a very thin electrode array is introduced into the cochlea of the inner ear, where it stimulates the remaining nerve fibers (1,2). The operation is complicated; it is performed with the aid of a microscope, and involves drilling very close to vital vessels and important nerves. The method was introduced in Sweden in 1984 by Professor Göran Bredberg, then at Stockholm Söder Hospital. High resolution computed tomography (CT) of the temporal bone is a part of the preoperative evaluation preceding cochlear implantation. It is a method for visualizing the bony structures of the middle and inner ear - to diagnose pathology and to describe the anatomy. In Stockholm, these examinations have usually been performed at the Radiology Department of Stockholm Söder Hospital. Examinations of cochlear implant candidates from other parts of Sweden and from abroad are also sent there for special reviewing. The first work concerns CT of the temporal bone and cochlear implant surgery in children with CHARGE association. This is a rare condition with multiple congenital abnormalities, sometimes lethal. Children with CHARGE have different combinations of disabilities, of which impairments of vision and hearing, as well as balance problems and facial palsy can lead to developmental delay. There have been few reports of radiological temporal bone changes and none of cochlear implant surgery for this group. The work includes a report of the findings on preoperative CT and at surgery, as well as post-implant results in two children. A review of the latest diagnostic criteria of CHARGE and the temporal bone changes found in international literature is also included. The conclusion was that certain combinations of temporal bone changes in CHARGE are, if not specific, at least extremely rare in other materials. CT can visualize these changes and be used as a diagnostic tool. This is important, since some of the associated disabilities are not so obvious from the start. Early treatment is vital for the child's development. This work also shows that cochlear implantation may help some of these often very isolated children to communicate. The second work is a radioanatomic study of one of the structures of the inner ear - the bony canal for the cochlear nerve. It involves measurements of the dimensions of the canal on 117 silicone rubber casts of the temporal bone (from a unique collection of casts at Uppsala temporal bone laboratory) and on 50 clinical CT-studies (100 ears). The purpose was to show the normal variation, which is of use in the appraisal of congenital temporal bone malformations on CT. Based on our results we propose that if the canal is less than 1.4 mm, as measured on CT, the possibility of cochlear nerve abnormality should be considered. This is of interest since aplasia of the cochlear nerve is a contraindication to cochlear implantation. If the canal is wider than 3.0 mm, then other anomalies may coexist, with the risk of CSF gusher when a cochleostomy or stapedectomy is performed.
Svensson J. Contrast-Enhanced Magnetic Resonance Angiography. Development and optimization of techniques for paramagnetic and hyperpolarized contrast media. Stockholm 2001. ISBN 91-628-5322-8. Contrast-enhanced magnetic resonance angiography (CE-MRA) is a diagnostic method for imaging of vascular structures based on nuclear magnetic resonance. Vascular enhancement is achieved by injection of a contrast medium (CM). Studies were performed using two different types of CM: conventional paramagnetic CM, and a new type ofCMbased on hyperpolarized (HP) nuclei. The effects of varying CM concentration with time during image acquisition were studied by means of computer simulations using two different models. It was shown that a rapid concentration variation during encoding of the central parts of k-space could result in signal loss and severe image artifacts. The results were confirmed qualitatively with phantom experiments. A postprocessing method was developed to address problems with simultaneous enhancement of arteries and veins in CE-MRA of the lower extremities. The method was based on the difference in flow-induced phase in the two vessel types. Evaluation of the method was performed with flow phantom measurements and with CE-MRA in two volunteers using standard pulse sequences. The flow-induced phase in the vessels of interest was sufficient to distinguish arteries from veins in the superior-inferior direction. Using this method, the venous enhancement could be extinguished. The possibility of using HP nuclei as CM for CE-MRA was evaluated. Signal expressions for a flow of HP CMimaged with a gradient echo sequence were derived. These signal expressions were confirmed in phantom experiments using HP 129Xe dissolved in ethanol. Studies were also performed with a new CM based on HP 13C. The CM had very long relaxation times (T 1,in vivo/T 2,in vivo ≈ 38/1.3 s). The long relaxation times were utilized in imaging with a fully balanced steady-state free precession pulse sequence (trueFISP), where the optimal flip angle was found to be 180°. CE-MRA with the 13C-based CM in rats resulted in images with high vascular SNR (∼500). CE-MRA is a useful clinical tool for diagnosing vascular disease. With the development of new contrast media, based on hyperpolarized nuclei for example, there is a potential for further improvement in the signal levels that can be achieved, enabling a standard of imaging of vessels that is not possible today.
Contrast-enhanced magnetic resonance angiography (CE-MRA) is a diagnostic method for imaging of vascular structures based on nuclear magnetic resonance. Vascular enhancement is achieved by injection of a contrast medium (CM). Studies were performed using two different types of CM: conventional paramagnetic CM, and a new type of CM based on hyperpolarized (HP) nuclei. The effects of varying CM concentration with time during image acquisition were studied by means of computer simulations using two different models. It was shown that a rapid concentration variation during encoding of the central parts of k-space could result in signal loss and severe image artifacts. The results were confirmed qualitatively with phantom experiments. A postprocessing method was developed to address problems with simultaneous enhancement of arteries and veins in CE-MRA of the lower extremities. The method was based on the difference in flow-induced phase in the two vessel types. Evaluation of the method was performed with flow phantom measurements and with CE-MRA in two volunteers using standard pulse sequences. The flow-induced phase in the vessels of interest was sufficient to distinguish arteries from veins in the superior-inferior direction. Using this method, the venous enhancement could be extinguished. The possibility of using HP nuclei as CM for CE-MRA was evaluated. Signal expressions for a flow of HP CM imaged with a gradient echo sequence were derived. These signal expressions were confirmed in phantom experiments using HP 129Xe dissolved in ethanol. Studies were also performed with a new CM based on HP 13C. The CM had very long relaxation times (T1, in vivo/T2, in vivo approximately 38/1.3 s). The long relaxation times were utilized in imaging with a fully balanced steady-state free precession pulse sequence (trueFISP), where the optimal flip angle was found to be 180 degrees. CE-MRA with the 13C-based CM in rats resulted in images with high vascular SNR (approximately 500). CE-MRA is a useful clinical tool for diagnosing vascular disease. With the development of new contrast media, based on hyperpolarized nuclei for example, there is a potential for further improvement in the signal levels that can be achieved, enabling a standard of imaging of vessels that is not possible today.
Non-specific white matter changes (WMC) in the brain are common findings in the elderly population. Although they are frequently seen in non-demented persons, WMC seem to be more common in demented patients. The significance of these changes, as well as their pathophysiological background, is incompletely understood. The aim of this thesis was to study different aspects of WMC using MR imaging (MRI) and to investigate the clinical significance of such changes in subjects with mild cognitive impairment or dementia. In study I post-mortem MRI of the brain was compared to corresponding neuropathology slices. WMC were quantified and found to be more extensive on neuropathology. The areas that appeared normal on MRI but not on histopathology represented only minor changes with increased distance between the myelinated fibres but with preserved axonal network and glial cell density. Study II evaluated the blood-brain barrier (BBB) integrity to investigate if an increased permeability could be shown in WMC. A contrast-enhanced MRI technique was used to detect small degrees of enhancement. No general increase in BBB could be detected in the WMC areas. In study III the relation between WMC and apolipoprotein E (APOE) genotype was explored in patients with Alzheimer's disease (AD). Results showed that AD patients, who were homozygous for the APOE epsilon 4 allele had more WMC than patients with other genotypes. This was most significant for changes in the deep white matter. Results also indicated that in AD patients carrying the epsilon 4 allele, WMC are not age-related phenomena, but might be related to the aetiology of the disease. Study IV aimed to investigate if WMC in a specific brain region affect cognitive functions related to that area. Periventricular WMC in the left frontal lobe predicted a decrease in initial word fluency, a test though to reflect left frontal lobe functioning. This indicates that WMC might have specific effects in different brain regions. In study V we evaluated the prognostic significance of WMC in patients with memory impairment, regarding the rate of further global cognitive decline. There was no difference in outcome between patients having extensive WMC and a matched control group, during 2-4 years of follow up, and assessed by the "Mini-Mental State Examination". In conclusion, this work has shown and characterised pathological changes in the white matter not visible on conventional MRI. We have also shown that there is no major general increase in BBB permeability in areas of WMC. In addition, homozygosity with regard to the APOE epsilon 4 gene allele implies an increased extent of WMC in AD patients. In AD patients carrying this gene allele, WMC are not merely age-related phenomena, but might be related to the aetiology of the disease. We also claim that WMC in a specific location might impair cognitive functions that rely on those specific pathways. In contrast, WMC do not seem to have any prognostic value in predicting the rate of global cognitive decline in patients at a memory clinic.
UNLABELLED:X-rays are known to cause malignancies, skin damage and other side effects and they are thus potentially dangerous. Therefore, it is essential and in fact mandatory to reduce the radiation dose in diagnostic radiology as far as possible. This is also known as the ALARA (as low as reasonably achievable) principle. However, the dose is linked to image quality and the image quality may not be lowered so far that it jeopardizes the diagnostic outcome of a radiographic procedure. The process of reaching this balance between dose and image quality is called optimization. The aim of this thesis was to propose and evaluate methods for optimizing the radiation dose-image quality relationship in diagnostic radiography with a focus on clinical usefulness. The work was performed in three main parts. OPTIMIZATION OF SCOLIOSIS RADIOGRAPHY: In the first part, two recently developed methods for digital scoliosis radiography (digital exposure and pulse fluoroscopy) were evaluated and compared to the standard screen-film method. Radiation dose was measured as kerma area-product (KAP), entrance surface dose (ESD) and effective dose; image quality was assessed with a contrast-detail phantom and through visual grading analysis. Accuracy in angle measurements was also evaluated. The radiation dose for digital exposure was nearly twice as high as the screen-film method at a comparable image quality while the dose for pulsed fluoroscopy was very low but with a considerably lower image quality. The variability in angle measurements was sufficiently low for all methods. Then, the digital exposure protocol was optimized to a considerably lower dose with a slightly lower image quality compared to the baseline. FLAT-PANEL DETECTOR: In the second part, an amorphous-silicon direct digital flat-panel detector was evaluated using a contrast-detail phantom, measuring dose as entrance dose. The flat-panel detector yielded a superior image quality at a lower dose than both storage phosphor plates and screen-film. Equivalent image quality compared to storage phosphor plates was reached at about one-third of the dose. OPTIMIZATION OF PERCUTANEOUS CORONARY INTERVENTION (PCI): In the third part, influence of various settings on radiation dose and image quality in coronary catheterisation and PCI was investigated. Based on these findings, the dose rate for fluoroscopy was reduced to one-third. The dose reduction was evaluated in a clinical series of 154 PCI procedures before and 138 after the optimization. Through this optimization, the total KAP was significantly reduced to two-thirds of the original value.IN SUMMARY:This thesis indicates the possibility of dose reduction in diagnostic radiology through optimization of the radiographic process.
Sanfridsson J.: Orthopaedic measurements with computed radiography. Methodological development, accuracy, and radiation dose with special reference to the weight-bearing lower extremity and the dislocating patella. Lund 2001. ISBN 87-16-16449-0. The overall aim of this study was to develop and evaluate a measurement system for computed radiography (CR) and Picture Archiving and Communication Systems (PACS), permitting measurements of long distances and angles in and between related images. The developed measurement system, which was based on the QUESTOR Precision Radiography (QPR) system, was applied to the weight-bearing knee with special reference to the dislocating patella. The QPR system modified for CR fulfilled the criteria for measuring the weight-bearing knee. The special measuring assistance tools that were developed were important for the implementation of CR and PACS, particularly in workstations programmed for musculoskeletal radiology. The energy imparted to the patient was reduced by 98% at the lowest exposure of the CR-system, compared with our conventional analogue method, without loss of diagnostic accuracy. The CR technique creates a possibility, to an extent not previously feasible, to differentiate the exposure parametres (and thus minimise the radiation dose to the patient) by carefully considering the purpose of the examination. A radiographic method for measuring the rotation of the femur and the tibia, the, and the patellar translation was developed and applied to healthy volunteers. The introduced patellar variables have yielded new insights into the complex sequence of motions between the femur, tibia, and patella. The patients with a dislocating patella were subdivided into one "clean" group of spontaneous dislocations and one group with various traumas in the history, which thus resulted in two groups with distinct radiographic differences. The Q-angle was decreased in knees that had suffered dislocations, and the traditional surgical treatment with a further reduction of the Q-angle must be challenged. The use of clinical measurements of the Q-angle was not an optimal way to evaluate the mechanical alignment in the patellofemoral joint under physiological conditions. In this study, we have proved that the developed method for CR and PACS is a useful technique for measurements in and between related images, and is superior to the conventional analogue technique .
In contrast-enhanced MR angiography (CE-MRA), vascular signal is produced by the acquisition of a T1-weighted MR imaging scan while the presence of a contrast agent induces a low T1 in blood. In this thesis, CE-MRA of the aortoiliac arteries was evaluated. Different contrast agents and techniques for synchronisation of the scan with the contrast bolus passage were assessed. In 30 patients with clinically suspected iliac artery stenoses, CE-MRA was compared with duplex ultrasound scanning (DUS) and digital subtraction X-ray angiography (DSA), with intra-arterial pressure measurements as reference. No statistically significant differences in sensitivity or specificity were observed between the techniques regarding detection of haemodynamically significant iliac stenoses. The use of multiplanar reformat and source images in the MRA examinations was of value for differentiation between highgrade stenoses and occlusions. With DSA as reference method, MRA had significantly higher sensitivity and specificity than DUS for detection of > or = 50% stenoses. In 14 patients who underwent iliac artery MRA, differences in contrast arrival time of up to 7 s were observed between the aorta and the common femoral artery. A dual-station timing technique adjusting for this difference was found feasible. Compared with a fluoroscopically triggered technique (n = 13), which is used in clinical routine, the dual-station technique was more reliable for the visualisation of distal vessels. In a clinical phase II study comparing doses of the contrast agent gadobenate dimeglumine from 0.0125 to 0.2 mmol/kg b.w. for enhancement of iliac artery MRA, significant improvement in subjective diagnostic quality compared with time-of-flight-MRA was found at all doses from 0.025 mmol/kg b.w. An increasing trend with dose was observed up to a dose of 0.05-0.1 mmol/kg b.w. In a phase I clinical study on the intravascular iron oxide contrast agent NC100150 Injection, a positive dose response was observed for abdominal vascular enhancement, with the highest contrast-to-noise ratio observed at 4.0 mg Fe/kg b.w. at 1.5 T and at 2.5-4 mg Fe/kg b.w. at 0.5 T. At 1.5 T higher calculated R2* values were found for the aorta than for the inferior vena cava.
Screening mammograms comprising of 32 first round, 10 interval and 32 second round detected cancers and 46 normal were examined by an expert screener, a screening radiologist, a clinical radiologist and a computer-assisted diagnosis (CAD) system. The expert screener, screening radiologist, clinical radiologist and the CAD detected 44, 41, 34 and 37 cancers, respectively, while their respective specificities were 80%, 83%, 100% and 22%. Later, with CAD prompting, the screening and the clinical radiologist detected 1 and 3 additional cancers each with unchanged specificities. Screening mammograms comprising 35 first round, 12 interval and 14 second round detected cancers and 89 normal findings were examined without and with previous mammograms by experienced screeners. Without previous mammograms, the screeners detected 40.3 cancers with a specificity of 87%. With previous mammograms, 37.7 cancers were detected with a 96% specificity. The decrease in sensitivity was not significant but the screeners showed significant increase in specificity. Local recurrences in 303 nonpalpable breast cancers with preoperative localizations and breast conservation therapy were evaluated for needle-caused implant metastasis. A total of 214 percutaneous biopsies were performed. There were 33 local recurrences. Needle-caused seeding or implantation as based on the location of the recurrence in comparison to the needle path in the mammograms was suspected in 3/44 (7%) invasive cancers without radiotherapy. The mammographic characteristics of 317 nonpalpable breast cancers were categorized. Logistic regression showed that the risk ratios for a spiculated mass without calcifications and calcifications alone were 12 and 19 for invasive cancer and ductal cancer in situ (DCIS), respectively. Invasive ductal grade 1, ductal grade 2, lobular and ductal grade 3, had a risk ratio (RR) of 28, 17, 11 and 4.6, respectively, for a spiculated mass without calcifications. DCIS nuclear grade 3 and invasive ductal grade 3 had an RR of 17 and 9.7, respectively, for sole casting calcifications. The eight-year survival of 96 1-9-mm invasive breast cancers were investigated in relation to their mammographic appearance, node status and histologic grade. After a median follow-up of 7 years, 6/96 died from breast cancer: 3/14 had calcifications alone, 2/56 had spiculated masses, 1/12 had rounded mass, 5/78 were node-negative and 1/4 was node-positive. The survival rate was 93%: 77% for the calcifications alone, 95% for spiculated masses, 91% for rounded masses, 92% for node-negative and 75% for node-positive. Calcifications alone and node positivity, each, carried a significantly higher risk of death.
