Martti Kormano

University of Turku, Turku, Western Finland, Finland

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Publications (86)232.02 Total impact

  • No preview · Article · Jun 2002 · Academic Radiology

  • No preview · Article · May 2002 · Academic Radiology
  • Marianne Maass · Marjatta Kosonen · Martti Kormano
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    ABSTRACT: Introduction of a picture archiving and communication system (PACS) into an old hospital poses several problems since the system cannot be implemented instantaneously. We analysed the costs of a halfway implemented PACS in Turku University Central Hospital (TUCH) during 1998. Manual and digital archiving in 1998 continued parallel so that only 10% reduction of film usage was achieved. A 21% increase in image manipulation and storage expenses occurred. A calculation based on potential 90% reduction of film usage and changes in the amount of personnel suggest some direct savings. Also, indirect savings due to more efficient patient treatment and the reduction of time spent in the hospital, and overhead costs of information handling are expected to lead to savings. However, these savings were not included in our calculations. When full-scale PACS is installed, equipment investments, network and digital ware maintenance costs will drop from 121 to 116% compared with traditional film archiving activity costs.
    No preview · Article · Aug 2001 · Computer Methods and Programs in Biomedicine
  • Marianne Maass · Aaro Kiuru · Martti Kormano
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    ABSTRACT: This study was designed to evaluate effectiveness of radiological image data compression in terms of image quality and archiving material costs using DLT tapes, and to assess the relationship between loss of quality and cost savings. Six radiologists used Subjective Fidelity Criteria (SFC) in random fashion to evaluate the quality of 105 digitally acquired radiological images. In addition, 5 radiologists and 2 nonradiologists evaluated at random three phantom images exposed in conditions mimicking chest, bone, and colon examinations, displayed in five modes (a total of 15 images). Both patient images and phantom images were submitted to 3:1 (Ziv-Lempel method) and 10:1 compression (wavelet-based compression method). Cost information on material cost savings and the effect of compression on tape space requirements were compared. The results indicate that image quality was not degraded using either of the compression ratios. The interobserver proportion of agreement exceeded overwhelmingly the limit of a good proportion of agreement regarding each compression ratio and each image type. The divergence in the rest of the assessments was not consistent. The adoption of 10:1 compression would not bring a substantial decrease of archiving costs as compared to the total yearly operating costs, and especially as considering the consequences of possible image quality deterioration.
    No preview · Article · Feb 2001 · Telemedicine and e-Health
  • Marianne Maass · Marjatta Kosonen · Martti Kormano
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    ABSTRACT: Since 1996, Turku University Central Hospital has offered teleradiology consultations regarding computerized tomography examinations of the brain to three regional hospitals in Finland, in which neurosurgical or neuroradiological specialist services are not available, in order to avoid unnecessary patient transportation. We performed a retrospective survey of the teleconsultations performed in 1998. Medical records and the relevant radiology images were obtained. During the study period, teleconsultations were carried out for a total of 83 patients, of whom 16 were transported to the university hospital (i.e. 81% of these patients had avoided unnecessary transportation). The total savings amounted to 42,100 ECU. Of the 16 transported patients, 12 were immediately operated on in the university hospital. It was judged that, because of the consultation service, the patients undergoing an operation had benefited from a more rapid and a more complete recovery. In 1998 the teleradiology consultation service was established as part of the routine work of the Medical Imaging Centre and a fee for its services was adopted.
    No preview · Article · Feb 2000 · Journal of Telemedicine and Telecare
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    ABSTRACT: The aim of the study 'Dynamic Chest Image Analysis' is to develop computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected at different phases of the respiratory/cardiac cycles in a short period of time. We have proposed a framework for ventilation study with an explicit ventilation model based on pyramid images. In this paper, we extend the framework to pulmonary perfusion study. A perfusion model and the truncated pyramid are introduced. The perfusion model aims at extracting accurate, geographic perfusion parameters, and the truncated pyramid helps in understanding perfusion at multiple resolutions and speeding up the convergence process in optimization. Three cases are included to illustrate the experimental results.
    Full-text · Article · Jul 1998 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: The purpose of this study was to evaluate 1/T1ρ in relation to 1/T1 and 1/T2 in characterizing normal and diseased muscle. We measured the muscle relaxation rates 1/T1 and 1/T2 at 0.1 T and 1/T1ρ at on-resonance locking fields B1 between 10 and 160 μT in myositis patients and normal volunteers. 1/T2 and 1/T1ρ of muscle were lower in the patients than in the volunteers, whereas there was no difference in the 1/T1 values. The lower relaxation rates 1/T2 and 1/T1ρ in the diseased muscle may be due to fat and connective tissue infiltrations and edema. 1/T1ρ contrast between muscle and subcutaneous fat was higher than 1/T2 and 1/T1 contrast. This may be explained by the different B1 dispersion behavior of these two tissue types. 1/T1ρ of fat is B1 field independent, whereas 1/T1ρ of muscle decreases clearly with increasing B1 field. In conclusion, 1/T1ρ provides a useful tool in manipulating contrast in magnetic resonance imaging of diseased muscle.
    No preview · Article · May 1998 · Magnetic Resonance Imaging
  • Anette Virta · Markku Komu · Nina Lundbom · MD Martti Kormano
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    ABSTRACT: The authors evaluated the value of T1 rho in relation to T1 and T2 in the characterization of human muscles. The authors studied the effect of muscle type (anterior tibial [AT] and gastrocnemius [GC]), sex, and age on 1/T1 and 1/T2 at 0.1 T and on 1/ T1 rho at locking-field B1s (spin-locking radio-frequency magnetic induction field) of 10-160 microT in 38 healthy volunteers. The contrast-to-noise ratio (CNR) between muscle and fat was evaluated with different T1-, T2-, and T1 rho-weighted magnetic resonance (MR) sequences. The 1/T1, 1/T2, and 1/T1 rho were slightly higher in AT than in GC muscles. The 1/T2 and 1/T1 rho of AT muscles showed a sex dependence, whereas no correlation with age was found. The CNR of the T1 rho-weighted images did not markedly differ from that of the T1- and T2-weighted images. T1 rho is as sensitive as T2 to the composition of muscle, whereas T1 is less sensitive. In MR imaging of normal muscle, T1 rho and T2 provide a relatively similar tissue contrast.
    No preview · Article · Mar 1998 · Academic Radiology
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    ABSTRACT: The aim of the study 'dynamic chest image analysis' is to develop computing analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected at different phases of the respiratory/cardiac cycles. A multiresolutional method for ventilation study with an explicit ventilation model based on pyramid images is proposed in this paper. The ventilation model is sophisticated enough in coverage of both inhalation and exhalation phases, but also remains simple enough in model realization. This model plays a critical role in extracting accurate, geographic ventilation parameters; while the pyramid helps in understanding ventilation at multiple resolutions and speeding up the convergence process in optimization. A number of patients have been studied with a research prototype produced in MATLAB. The prototype has proven to be useful aid in dynamic pulmonary ventilation study. However, for clinical use, further work must be done in the future.
    No preview · Article · May 1997 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: To study splenic perfusion with use of computed tomography (CT). Twenty-six control patients without splenoportal disease, six with cirrhosis, and seven with other splenic disease were examined with electron-beam CT. Twenty-five milliliters of iohexol (300 mg of iodine per milliliter) was given intravenously at 10 mL/sec followed by a saline bolus. Multiple single-level axial sections were acquired 8-90 seconds after injection. Perfusion was calculated by dividing maximal splenic enhancement by the area under the circulation-corrected aortic time-enhancement curve. Subjective assessments of enhancement heterogeneity were made, and regional perfusion was calculated in 10 patients with heterogeneous enhancement. Total splenic volume and blood flow were computed in 21 patients. Mean perfusion (controls: 1.29 mL/min/mL, miscellaneous group: 1.07 mL/min/mL) was close to predictions. There was a trend toward lower perfusion in cirrhotic patients (0.87 mL/min/mL), but the difference was not statistically significant. Total splenic blood was increased in patients with cirrhosis (P < .01). Marked perfusion heterogeneity was observed in 41% of spleens, but by 2 minutes splenic enhancement was uniform. CT shows promise in the study of splenic blood flow.
    No preview · Article · Jan 1997 · Academic Radiology
  • Anette Virta · Markku Komu · Martti Kormano
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    ABSTRACT: The effect of molecular weight, concentration, and structure on 1/T1rho, the rotating frame relaxation rate, was investigated for several proteins using the on-resonance spin-lock technique, for locking fields B1 < 200 microT. The measured values of 1/T1rho were fitted to a simple theoretical model to obtain the dispersion curves 1/T1rho(omega1) and the relaxation rate at zero B1 field, 1/T1rho(0). 1/T1rho was highly sensitive to the molecular weight, concentration, and structure of the protein. The amount of intra- and intermolecular hydrogen and disulfide bonds especially contributed to 1/T1rho. In all samples, 1/T1rho(0) was equal to 1/T2 measured at the main magnetic field Bo = 0.1 T, but at higher locking fields the dispersion curves monotonically decreased. The results of this work indicate that a model considering the effective correlation time of molecular motions as the main determinant for T1rho relaxation in protein solutions is not valid at very low B1 fields. The underlying mechanism for the relaxation rate 1/T1rho at B1 fields below 200 microT is discussed.
    No preview · Article · Jan 1997 · Magnetic Resonance in Medicine
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    ABSTRACT: Objective: To determine whether T1- or T2*-weighted sequences are more informative and practical in dynamic Gd-DTPA-enhanced MR imaging for the evaluation of renal blood flow and function. Materials and Methods: Dynamic Gd-DTPA-enhanced MR imaging of the kidney was performed in 7 patients by either Tl-weighted TurboFLASH (TR/TE/TI/FA = 9/4/27/8) or T2*-weighted FLASH (TR/TE/FA = 32/22/10) sequences for comparison of the enhancement pattern. None of the subjects had a suspicion of renal dysfunction from laboratory data, and the absence of renal artery stenosis was confirmed by conventional angiography. Results: During the early phase, the marked signal increase in T1-weighted imaging in the renal cortex corresponded to a similar marked decrease in signal intensity in T2*-weighted imaging. During the middle and late phases, the medulla was dramatically decreased in intensity on the T2*-weighted imaging resulting in a good contrast between the cortex and medulla. Conclusion: Both sequences may provide almost similar information about the renal cortical blood flow. However, T2*-weighted dynamic MR imaging may be more informative than T1-weighted dynamic MR imaging about the concentrating ability in the renal medulla. A high concentration of Gd-DTPA in the tubular structure was suspected to cause a dramatic decrease in intensity in the medulla in T2*-weighted imaging.Copyright © 1996 S. Karger AG, Basel
    No preview · Article · Nov 1996 · American Journal of Nephrology

  • No preview · Article · Sep 1996 · Academic Radiology
  • Timo Kurki · Nina Lundbom · Markku Komu · Martti Kormano
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    ABSTRACT: T1s and magnetization transfer (MT) parameters of 36 intracranial tumors were determined in vivo at 0.1 T to assess their use in tissue characterization. The mobile water relaxation times (T1w) did not differ between tumor groups, whereas the T1s, the apparent MT relaxation times (T1a), and the parameters MT contrast (MTC) differed significantly between several tumor types. The MT rates (Rwm) demonstrated the most significant differences; Rwm values could reliably separate high grade and low grade gliomas. T1ws of the tumors were commonly in the same range as that of normal gray matter, whereas other parameters differed from those of normal brain. The results indicate that MT rates are superior to other parameters in the characterization of intracranial tumors and may be also useful clinically in the grading of gliomas.
    No preview · Article · Jul 1996 · Journal of Magnetic Resonance Imaging
  • Anette Virta · Martti Kormano · Jorma Paranko
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    ABSTRACT: Magnetization transfer (MT) imaging provides a novel opportunity to characterize interactions between tissue water and macromolecules. Although several in vitro investigations have shown that proteins and lipids are important determinants of MT, the contribution of DNA is still unknown. This study was designed to determine whether DNA and cell nuclear material exhibit MT. We measured the magnetization transfer effect of pure DNA strands and purified bovine sperm head nuclei. Although no transfer of magnetization could be detected in samples of pure DNA strands, the sperm head nuclei exhibited a strong MT effect that increased with increasing solid content of the samples. Since the purified bovine sperm head samples consist of large nuclei with only minor traces of perinuclear matrix, the measured MT effect arises from the chromatin of the nuclei. The DNA fills 90% of the nuclear volume and it is extremely tightly packed as chromatin fibers by nucleoproteins. We hypothesize that the numerous intra- and intermolecular disulfide bonds that stabilize the chromatin fibers restrict the movement of the surface water binding sites of both DNA and protamines and thus facilitate the transfer of magnetization. Therefore, the results indicate that the amount of nuclear material may positively contribute to MT in tissues.
    No preview · Article · Jul 1996 · MAGMA Magnetic Resonance Materials in Physics Biology and Medicine
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    ABSTRACT: In the present study we introduce a new device for exercise magnetic resonance spectroscopy (MRS). It operates in a standard whole-body scanner. Mechanical exertion unit allows maximal 10° to 15° short-arc knee extensions. The device operates hydraulically and is based on isokinetic movement. The force and work conducted are automatically controlled by the electronic control and computer unit. A small surface coil placed on the vastus medialis muscle allows the collection of spectra without interfering spectra from nearby resting muscles. The force used for the extensions can be followed simultaneously as a curve on the screen in the operator's room and the data is transferred to a personal computer for later analysis. Total work and fatigue percentage are also calculated by the device. It also allows the use of different isokinetic exercise protocols. The measurements of force proved reliable in repeat measurements using an isokinetic test device as a control. This device has been used clinically for over a year, is easy to operate, and offers reliable measurements. It is well suited to trials where muscle energy states versus time are followed since it allows noninvasive simultaneous quantification of muscle performance and collecting MRS spectra at rest, during exercise, and in the recovery phase.
    No preview · Article · May 1996 · MAGMA Magnetic Resonance Materials in Physics Biology and Medicine
  • Sami Kajander · Markku Komu · Pekka Niemi · Martti Kormano
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    ABSTRACT: In order to study the applicability of magnetization transfer contrast (MTC) to tissue differentiation, the determination of the magnetization transfer (MT) parameters of normal tissues is necessary for the evaluation of pathological conditions. The time-dependent saturation transfer technique was used to investigate the observed magnetization transfer parameters in several human tissues in vivo at 0.1 T. The length of the off-resonance saturation pulse varied from 0 to 750 ms. The magnetization transfer contrast (MTC) was 0.71 in striated muscle, 0.49 in liver, 0.49 in renal cortex, and 0.50 in spleen. The observed magnetization transfer rates (Rwm) were 5.5 s-1 for muscle, 3.1 s-1 for liver, and 1.5 s-1 for both renal cortex and spleen. Our results indicate that measuring Rwm and possibly other relaxation parameters could be useful in tissue differentiation.
    No preview · Article · Feb 1996 · Magnetic Resonance Imaging
  • Anette Virta · MSc Markku Komu · MD Martti Kormano · Nina Lundbom
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    ABSTRACT: We observed the magnetization transfer rates in a variety of protein solutions at 0.1-T magnetic field and compared our results with previous investigations at high magnetic fields (> 0.5 T). The effects of protein concentration, size, pH, denaturation, cross linking, and fiber formation were investigated. We used the saturation transfer technique to determine the transfer of magnetization in gamma globulin, fibronectin, collagen, fibrinogen, and albumin solutions. The observed transfer rate increased with increasing concentration and size of the protein. Protein degradation decreased the transfer rate. Cross linking and fiber formation each increased the transfer rate, whereas buffer pH had no effect. Protein denaturation, aggregation, and fiber formation are important determinants of magnetization transfer in vitro. The size, concentration, and cross linking of the proteins contribute strongly to the transfer of magnetization at low fields, and the effect seems to be at least as important as at the higher fields.
    No preview · Article · Sep 1995 · Academic Radiology
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    ABSTRACT: Our goal was to quantify absolute hepatic arterial and portal venous perfusion noninvasively in patients with and without liver disease using ultrafast CT. A single slice through the porta hepatis was repeatedly scanned after bolus injection of 25 ml of iohexol 300 mg I/ml, followed by a 25 ml saline "chaser" intravenously at 10 ml/s. Thirty-nine controls, 7 cirrhotic patients, and 5 patients with known metastases on the slice plane were studied; hepatic arterial perfusion was determined in 41 patients and portal venous perfusion in 24. Time-attenuation curves from regions of interest drawn over the liver, spleen, aorta, and portal vein were analysed. Hepatic arterial perfusion was calculated by dividing the peak gradient of the liver time-attenuation curve prior to the time of peak splenic attenuation by the peak aortic CT number increase. Splenic perfusion was calculated by dividing the peak gradient of the splenic time-attenuation curve by the peak aortic CT number increase. Portal perfusion was derived by scaling the splenic time-attenuation curve by the ratio of hepatic arterial/splenic perfusion. This scaled curve was subtracted from the liver time-attenuation curve to give a portal curve. The peak up-slope of this curve was divided by the peak rise in splenic or portal vein density. Hepatic arterial perfusion averaged 0.19 ml/min/ml (n = 31) in controls and was raised in cirrhosis to 0.25 ml/min/ml (n = 6) and metastases 0.43 ml/min/ml (n = 4). Portal venous perfusion was 0.93 ml/min/ml (n = 19) in controls and 0.43 ml/min/ml (n = 4) in cirrhosis. Reproducibility has been confirmed. Dynamic ultrafast CT shows potential in quantifying arterial and portal hepatic perfusion. The technique may be adaptable to dynamic bolus MRI.
    No preview · Article · May 1995 · Journal of Computer Assisted Tomography
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    ABSTRACT: Preoperative and postoperative magnetic resonance imaging (MRI) of the lumbar spine was performed on 41 patients treated either microsurgically or with percutaneous nucleotomy for lumbar disc herniation. On the first postoperative day, MRI revealed an edematous mass effect at the level of surgery in 25 (61%) patients. The mass effect caused compression of the anterior dural sac mimicking preoperative disc herniation. After the follow-up of 6 months, the mass effect had disappeared in all patients, and the MRI finding in the operated disc space was that of a prolapse in six (15%) patients and that of a protrusion in 16 (39%) patients. Postoperative scarring was detected in 23 (56%) patients. The amount of the epidural scar tissue was significantly (p = 0.0002) associated with the extent of the early postoperative hemorrhagic changes detected in these patients with MRI. No association was observed between these MRI findings (mass effect, disc herniation, epidural scarring) and the clinical outcome of the patients.
    No preview · Article · Jul 1994 · Surgical Neurology

Publication Stats

1k Citations
232.02 Total Impact Points


  • 1983-2002
    • University of Turku
      • Department of Diagnostic Radiology
      Turku, Western Finland, Finland
  • 1988-2001
    • Turku University Hospital
      • • Department of Radiology
      • • Department of Pediatrics
      Turku, Varsinais-Suomi, Finland
  • 1993
    • University of Chicago
      • Department of Radiology
      Chicago, Illinois, United States
  • 1978
    • Helsinki University Central Hospital
      Helsinki, Uusimaa, Finland