Publications by authors named "Tuomas Nieminen"

4 Publications

  • Page 1 of 1

Clinical characteristics and evaluation of the incidence of cryptococcosis in Finland 2004-2018.

Infect Dis (Lond) 2021 09 11;53(9):684-690. Epub 2021 May 11.

HUS Diagnostic Center, HUSLAB, Clinical Microbiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.

Background: Cryptococcosis is one of the major causes of mortality among HIV patients worldwide. Though most often associated with late stage HIV infection/AIDS, a significant number of cases occur in other immunocompromised patients such as solid organ transplant recipients and patients with hematological malignancies. Immunocompromised patients are a heterogeneous group and their number increases constantly. Since little is known about the incidence and the clinical features of cryptococcosis in Northern Europe, our aim was to investigate the clinical characteristics of cryptococcosis patients in Finland.

Methods: We retrospectively reviewed the laboratory confirmed cryptococcosis cases in Finland during 2004-2018. Only those who were treated for cryptococcosis were included in the study. Initial laboratory findings and medical records were also collected.

Results: A total of 22 patients with cryptococcosis were included in our study. The annual incidence of cryptococcosis was 0.03 cases per 100,000 population. Ten patients were HIV-positive and 12 out of 22 were HIV-negative. Hematological malignancy was the most common underlying condition among HIV-negative patients.

Conclusions: To our knowledge, this is the first study of the clinical presentation and incidence of cryptococcosis in Finland. We demonstrate that invasive cryptococcal infection occurs not only in HIV/AIDS patients or otherwise immunocompromised patients but also in immunocompetent individuals. Even though cryptococcosis is extremely rare in Finland, its recognition is important since the prognosis depends on rapid diagnostics and early antifungal therapy.
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September 2021

Evaluating severity of white matter lesions from computed tomography images with convolutional neural network.

Neuroradiology 2020 Oct 13;62(10):1257-1263. Epub 2020 Apr 13.

Department of Neurology, University of Helsinki and Helsinki University Hospital, PO Box 302, 00029 HUS, Helsinki, Finland.

Purpose: Severity of white matter lesion (WML) is typically evaluated on magnetic resonance images (MRI), yet the more accessible, faster, and less expensive method is computed tomography (CT). Our objective was to study whether WML can be automatically segmented from CT images using a convolutional neural network (CNN). The second aim was to compare CT segmentation with MRI segmentation.

Methods: The brain images from the Helsinki University Hospital clinical image archive were systematically screened to make CT-MRI image pairs. Selection criteria for the study were that both CT and MRI images were acquired within 6 weeks. In total, 147 image pairs were included. We used CNN to segment WML from CT images. Training and testing of CNN for CT was performed using 10-fold cross-validation, and the segmentation results were compared with the corresponding segmentations from MRI.

Results: A Pearson correlation of 0.94 was obtained between the automatic WML volumes of MRI and CT segmentations. The average Dice similarity index validating the overlap between CT and FLAIR segmentations was 0.68 for the Fazekas 3 group.

Conclusion: CNN-based segmentation of CT images may provide a means to evaluate the severity of WML and establish a link between CT WML patterns and the current standard MRI-based visual rating scale.
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October 2020

Oral Doxycycline Compared to Intravenous Ceftriaxone in the Treatment of Lyme Neuroborreliosis: A Multicenter, Equivalence, Randomized, Open-label Trial.

Clin Infect Dis 2021 04;72(8):1323-1331

Department of Infectious Diseases, Turku University Hospital and University of Turku, Turku, Finland.

Background: Lyme neuroborreliosis (LNB) is often treated with intravenous ceftriaxone even if doxycycline is suggested to be noninferior to ceftriaxone. We evaluated the efficacy of oral doxycycline in comparison to ceftriaxone in the treatment of LNB.

Methods: Patients with neurological symptoms suggestive of LNB without other obvious reasons were recruited. The inclusion criteria were (1) production of Borrelia burgdorferi-specific antibodies in cerebrospinal fluid (CSF) or serum; (2) B. burgdorferi DNA in the CSF; or (3) an erythema migrans during the past 3 months. Participants were randomized in a 1:1 ratio to receive either oral doxycycline 100 mg twice daily for 4 weeks, or intravenous ceftriaxone 2 g daily for 3 weeks. The participants described their subjective condition with a visual analogue scale (VAS) from 0 to 10 (0 = normal; 10 = worst) before the treatment, and 4 and 12 months after the treatment. The primary outcome was the change in the VAS score at 12 months.

Results: Between 14 September 2012 and 28 December 2017, 210 adults with suspected LNB were assigned to receive doxycycline (n = 104) or ceftriaxone (n = 106). The per-protocol analysis comprised 82 patients with doxycycline and 84 patients with ceftriaxone. The mean change in the VAS score was -3.9 in the doxycycline group and -3.8 in the ceftriaxone group (mean difference, 0.17 [95% confidence interval, -.59 to .92], which is within the prespecified equivalence margins of -1 to 1 units). Participants in both groups improved equally.

Conclusions: Oral doxycycline is equally effective as intravenous ceftriaxone in the treatment of LNB.

Clinical Trials Registration: NCT01635530 and EudraCT 2012-000313-37.
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April 2021

Global Burden of Small Vessel Disease-Related Brain Changes on MRI Predicts Cognitive and Functional Decline.

Stroke 2020 01 8;51(1):170-178. Epub 2019 Nov 8.

From the Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital (H.J., H.M.L., S. Melkas, T.E.), Finland.

Background and Purpose- Cerebral small vessel disease is characterized by a wide range of focal and global brain changes. We used a magnetic resonance imaging segmentation tool to quantify multiple types of small vessel disease-related brain changes and examined their individual and combined predictive value on cognitive and functional abilities. Methods- Magnetic resonance imaging scans of 560 older individuals from LADIS (Leukoaraiosis and Disability Study) were analyzed using automated atlas- and convolutional neural network-based segmentation methods yielding volumetric measures of white matter hyperintensities, lacunes, enlarged perivascular spaces, chronic cortical infarcts, and global and regional brain atrophy. The subjects were followed up with annual neuropsychological examinations for 3 years and evaluation of instrumental activities of daily living for 7 years. Results- The strongest predictors of cognitive performance and functional outcome over time were the total volumes of white matter hyperintensities, gray matter, and hippocampi (<0.001 for global cognitive function, processing speed, executive functions, and memory and <0.001 for poor functional outcome). Volumes of lacunes, enlarged perivascular spaces, and cortical infarcts were significantly associated with part of the outcome measures, but their contribution was weaker. In a multivariable linear mixed model, volumes of white matter hyperintensities, lacunes, gray matter, and hippocampi remained as independent predictors of cognitive impairment. A combined measure of these markers based on scores strongly predicted cognitive and functional outcomes (<0.001) even above the contribution of the individual brain changes. Conclusions- Global burden of small vessel disease-related brain changes as quantified by an image segmentation tool is a powerful predictor of long-term cognitive decline and functional disability. A combined measure of white matter hyperintensities, lacunar, gray matter, and hippocampal volumes could be used as an imaging marker associated with vascular cognitive impairment.
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January 2020