A Servo

Helsinki University Central Hospital, Helsinki, Southern Finland Province, Finland

Are you A Servo?

Claim your profile

Publications (34)71.52 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We assumed that patients with surgically treated aneurysmal subarachnoid hemorrhage (SAH) might have more lesions than those revealed by CT that could be visible on MR images. We conducted a retrospective study of a series of 147 patients with aneurysmal SAH who were treated surgically within 3 days of the onset of SAH. One hundred four patients (mean age, 48.8 years) underwent MR imaging studies 2.1 to 5.6 years (mean, 3.3 years) postoperatively. Eighty-four (81%) patients presented a total of 152 areas of increased signal intensity on T2-weighted images, consistent with infarction; 48% of the patients had lesions in the frontal lobes. CT performed 3 months postoperatively revealed hypodense areas on the scans of only 57% of the patients and showed lesions in the frontal lobes of only 16% of the patients. Patients who undergo early surgery for aneurysmal SAH have more lesions than are revealed by CT. The difference is remarkable, especially in the frontal lobes.
    Full-text · Article · Jun 2001 · American Journal of Neuroradiology
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess whether the capital investment required by advances in radiological technology is offset by savings in the direct costs of diagnostic services. Meningeoma was used as an indicator case. All meningeoma patients from three study periods were included: Twenty patients in 1976-77 before the introduction of CT, 22 patients in 1984-85 when CT was used and 16 patients in 1992 when MR imaging had replaced CT as the most informative imaging modality. Radiological and other diagnostic investigations, and the hospital stay were identified and cost analyzed. The costs of radiological examinations increased from 293 Euros in 1976-77 to 513 Euros in 1992. The average number of diagnostic examinations per patient decreased from 5.1 in 1976 77 to 2.4 in 1992. The length of hospital stay decreased from 11.5 to 2.7 days and the total costs of the diagnostic work-up decreased to one-third of the original, i.e. from 3423 Euros in 1976-77 to 1282 Euros in 1992. The costs of the radiological examinations rose, but the development of radiological technology simplified the diagnostic practice. The hospital stay drastically decreased. The total costs of diagnostic work-up per patient dropped to one-third of the baseline costs.
    No preview · Article · Dec 2000 · Acta Radiologica
  • Source
    S Juvela · J Ohman · A Servo · O Heiskanen · M Kaste
    [Show abstract] [Hide abstract]
    ABSTRACT: We studied adenosine diphosphate-induced platelet aggregation and the associated release of thromboxane B2 in 49 patients with subarachnoid hemorrhage in relation to angiographic vasospasm. Postoperative cerebral angiography was performed less than or equal to 3 (median 1) days after surgery for an aneurysm 5-14 days after subarachnoid hemorrhage. Correspondingly, one sample from each patient was taken within 24 hours either before or after angiography. The occurrence of severe as well as diffuse, moderate, or severe angiographic vasospasm was associated with the presence of delayed cerebral ischemia (p less than 0.05). Patients with diffuse angiographic vasospasm had significantly higher (p less than 0.05) values for thromboxane B2 release than the others, even after adjustment by the clinical grades on admission and before surgery, the timing of surgery, the time from subarachnoid hemorrhage to angiography and blood sampling, and nimodipine therapy. Severe and diffuse angiographic vasospasm were also associated with poor outcome at 1 year (p less than 0.05). Our results suggest that augmented release of platelet thromboxane may be involved in the pathogenesis of vasospasm in large cerebral arteries.
    Preview · Article · May 1991 · Stroke
  • J Kinnunen · A Servo · E M Laasonen · M Porras
    [Show abstract] [Hide abstract]
    ABSTRACT: Eighteen patients clinically suspected of having acoustic neurinoma were studied in both orbitomeatal and clivoaxial (CA) (the plane perpendicular to clivus) CT scanning planes during the same sessions. On the CA cuts there were highly significantly less (p less than 0.001) artifacts. Also, the tentorium was highly significantly (p less than 0.001) better visualized on the CA cuts. CA cuts could be recommended in cases when artifacts disturb the diagnostics of posterior fossa pathology or when detailed topographic information about pathologic anatomy round the tentorium is needed.
    No preview · Article · Jan 1991 · Röntgen-Blätter; Zeitschrift für Röntgen-Technik und medizinisch-wissenschaftliche Photographie
  • J Vilkki · P Holst · J Ohman · A Servo · O Heiskanen
    [Show abstract] [Hide abstract]
    ABSTRACT: A series of 83 patients was examined with a battery of cognitive tests, a clinical interview, and computed tomography 1 year after surgery for a ruptured intracranial aneurysm. Disability on the Glasgow Outcome Scale (33%), failure to return to work (25%), impaired social relations (25%), and subjective or clinical mental impairment (56%) were found to be related to each other and to poor performance on cognitive tests, especially to verbal impairments in patients with left lateral infarctions and to memory deficits and cognitive inflexibility in patients with frontal medial infarctions. Furthermore, cognitive deficits and poor outcome were associated with diffuse brain damage. Depression and anxiety were unrelated to test performances, but were frequently reported by patients with right lateral infarctions.
    No preview · Article · May 1990 · Neurosurgery
  • [Show abstract] [Hide abstract]
    ABSTRACT: Histological anaplasia, found in up to 10% of meningiomas, is an important prognostic sign as it is associated with increased recurrence rate and volume growth rate. We studied in retrospect a series of 230 primary intracranial meningiomas to discover whether histological anaplasia can be reliably foreseen in CT scans and angiograms. 205 meningiomas were histologically benign, and 25 meningiomas were classified as malignant (atypical or anaplastic), with either incipient (20) or overt (5) signs of anaplasia. Of ten CT parameters tested, three were associated significantly more often with malignant meningiomas: nodular contour (58.3% vs 26.7%), cysts (20.0% vs 4.4%) and absence of calcifications (92% vs 65.3%); none of these parameters was an absolute sign of anaplasia. 'Mushrooming', previously regarded as a definite sign of malignancy, was seen in 9% of benign meningiomas and in 21% of malignant ones. In angiography, no apparent differences between benign and malignant meningiomas were seen. The conclusion is that it is not possible to distinguish malignant meningiomas from benign ones with CT or angiography.
    No preview · Article · Feb 1990 · Neuroradiology
  • J Vilkki · P Holst · J Ohman · A Servo · O Heiskanen
    [Show abstract] [Hide abstract]
    ABSTRACT: A consecutive series of 118 patients operated on for ruptured intracranial arterial aneurysms was studied. Ninety-six of them could be adequately examined with a battery of psychological tests and computed tomographic scans 1 year after a subarachnoid hemorrhage. Seventeen orthopedic control patients with no history of brain damage were also tested. The pattern of cognitive deficits was strongly related to the findings on the computed tomographic scans. Patients with left lateral infarctions had deficits on performances requiring verbal efficiency, including memory and classification tasks, whereas patients who had right lateral infarctions were poor on a visuoconstructional task (the copying of Rey's Figure). These deficits were pronounced when lateral infarction was associated with diffuse brain damage. Patients with frontal medial infarctions had low scores on memory tests; the inefficiency in verbal fluency, categorical reasoning, and memory was related to diffuse brain damage. The patients who had no infarctions did not differ significantly from the control group. Cognitive impairments after left lateral and frontal medial infarctions, as well as diffuse brain damage, correlated with the Glasgow Outcome Scale.
    No preview · Article · Sep 1989 · Neurosurgery
  • Source
    J Vilkki · K Poropudas · A Servo
    [Show abstract] [Hide abstract]
    ABSTRACT: The relationship of memory and intelligence test performances to coma duration was studied in 51 head injured patients who had not been operated on for intracranial haematoma. Memory defect was related to coma duration, and was not secondary to impaired perceptual or conceptual analysis of the material to be remembered.
    Full-text · Article · Dec 1988 · Journal of Neurology Neurosurgery & Psychiatry
  • [Show abstract] [Hide abstract]
    ABSTRACT: Out of 936 primary intracranial meningiomas, 94.3% were histologically benign (grade I), 4.7% atypical (grade II), and 1.0% anaplastic (grade III); one recurrence was sarcomatous (grade IV). Meningiomas with histologic anaplasia (grades II-IV) occurred in 12% of the men, but only 4% of the women. Only 26% of atypical or anaplastic meningiomas appeared completely innocent on a computed tomography scan. Angiograms, usually showing a meningeal feeding artery, suggested meningioma when computed tomography scans did not. At 5 years after complete removal, the recurrence rate was only 3% (21% at 25 years) for benign meningiomas, but 38% for atypical ones, and 78% for anaplastic ones. The median times to recurrence were 7.5, 2.4, and 3.5 years, respectively. In spite of postoperative radiotherapy, four of five anaplastic meningiomas recurred.
    No preview · Article · Apr 1986 · Surgical Neurology
  • [Show abstract] [Hide abstract]
    ABSTRACT: A randomized double-blind study with iohexol and metrizamide in cervical myelography was performed in 100 patients. The concentration of the contrast medium was 240 mg I/ml. The image quality was equal with both contrast media. Forty-two per cent of the patients receiving iohexol had side effects (headache 22%, nausea 6%, vomiting 2% and mental reactions 6%), in contrast to 80 per cent of the patients receiving metrizamide (headache 56%, nausea 34%, vomiting 24% and mental reactions 26%). The majority of side effects appeared within 6 hours after injection of contrast medium. Two patients had a late onset of symptoms - one in each group. Once appearing, the side effects tended to be equally severe.
    No preview · Article · Feb 1986 · Acta radiologica. Supplementum
  • [Show abstract] [Hide abstract]
    ABSTRACT: At operation, 21 meningeal intracranial hemangiopericytomas resembled meningiomas, but differed histologically. They were frequently attached to sinuses, occipitally located, bled profusely at operation, and had a higher risk of recurrence and metastasis. Specific preoperative diagnosis is possible: computed tomography scan showed a meningiomalike tumor, which on the angiogram looked malignant and highly vascular. Two tumors showed a malignant growth pattern on computed tomography scan, "mushrooming." After a radical removal, three patients have lived for more than 10 years without recurrence; two of them were irradiated postoperatively. Three recurrent tumors were treated with radiotherapy only; one responded favorably.
    No preview · Article · Apr 1985 · Surgical Neurology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Thirty-two patients with severe cervical rheumatoid arthritis were investigated preoperatively with cervical myelography (CeM) and computed tomographic myelography (CTM). The severity of their clinical symptoms correlated excellently with a combination of the deformation of the spinal cord at the atlanto-axial level, the lateral dislocation of the cord at the same level, and the deformation of the cord at some lower cervical level. Obstructing soft-tissue excrescences seemed to have little significance. No correlation was found in this study between the deformation of the cord and the main findings of the plain films: the atlanto-axial subluxation (AAS), the vertical subluxation (VS), or their combination.
    No preview · Article · Feb 1985 · Neuroradiology
  • A Servo · E M Laasonen
    [Show abstract] [Hide abstract]
    ABSTRACT: The density of metrizamide injected accidentally into the spinal cord during cervical CT myelography was measured with CT scanning and compared with a series of dilutions of metrizamide scanned with a special phantom. The test suggests that the metrizamide is diluted rapidly in the spinal canal, and in an accidental intraspinal injection of metrizamide, it is not the contrast medium itself but the mechanical effect of the introduction of a volume of fluid that causes the neurological symptoms.
    No preview · Article · Feb 1985 · Neuroradiology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Twentyone primary intracranial haemangiopericytomas (HPC) were operated on from 1953 to 1983. The mean age of the 12 male and nine female patients was 38 years (17–64). Plain skull films showed well-defined bone destruction in two patients. Angiograms of 18 tumours (14 primary and four recurrent) showed the following when analysed according to the criteria of Marc et al. [4]: dual arterial supply (17/18), one-three main feeders giving rise to many irregular corkscrewlike vessels (16/18), dense, well-defined and long-lasting tumour stain (17/18), but early venous drainage rarely (1/18). The overall impression was that eight tumours appeared to be typical HPCs on angiogram. Five tumours had suggestive features, though not enough to justify specific angiographic diagnosis, and five were more like classical meningiomas. The larger tumours were more typical of HPCs, the smaller ones resembled meningiomas. CT scans of eight tumours (three primary and five recurrent) were available. The tumours were attached with a broad base to the convexity or other dural surfaces, often bilaterally. No calcifications were seen. There was little, if any, surrounding oedema. Contrast enhancement was strong and homogeneous. Four of the tumours were ring like, but the ring was thick and regular, in contrast to that in glioblastomas. The tumour margin was well-defined and smooth in three tumours, and nodular margins were seen in five; two of the latter grew extensively along dural surfaces. This sign may suggest aggressive biological behaviour. If both angiograms and CT scans are available, HPCs can be differentiated from glioblastomas and classical meningiomas, but perhaps not from anaplastic meningiomas.
    No preview · Article · Feb 1985 · Neuroradiology
  • A. Servo · E. M. Laasonen
    [Show abstract] [Hide abstract]
    ABSTRACT: The density of metrizamide injected accidentally into the spinal cord during cervical CT myelography was measured with CT scanning and compared with a series of dilutions of metrizamide scanned with a special phantom. The test suggests that the metrizamide is diluted rapidly in the spinal canal, and in an accidental intraspinal injection of metrizamide, it is not the contrast medium itself but the mechanical effect of the introduction of a volume of fluid that causes the neurological symptoms.
    No preview · Article · Jan 1985 · Neuroradiology
  • M. Porras · A. Servo · J. Jääskinen
    [Show abstract] [Hide abstract]
    ABSTRACT: Summary An 11-year-old girl was operated on for a frontal arteriovenous malformation in 1978; a postoperative carotid angiogram showed no filling of the AVM. The patient still had epilepsy. In 1981 a carotid angiogram showed no AVM. Some months later a new carotid angiography was done. In the first lateral series no AVM was seen but on the second injection with one more millilitre of contrast medium a large frontal AVM became apparent. The reasons for such variable filling are discussed.
    No preview · Article · Mar 1984 · Acta Neurochirurgica
  • M Porras · A Servo · J Jääskinen
    [Show abstract] [Hide abstract]
    ABSTRACT: An 11-year-old girl was operated on for a frontal arteriovenous malformation in 1978; a postoperative carotid angiogram showed no filling of the AVM. The patient still had epilepsy. In 1981 a carotid angiogram showed no AVM. Some months later a new carotid angiography was done. In the first lateral series no AVM was seen but on the second injection with one more millilitre of contrast medium a large frontal AVM became apparent. The reasons for such variable filling are discussed.
    No preview · Article · Feb 1984 · Acta Neurochirurgica
  • A Servo · M Porras · R Raininko
    [Show abstract] [Hide abstract]
    ABSTRACT: Computed tomography and angiographical findings of cavernous haemangiomas of the brain are reported on the basis of six cases of the authors, and a review of the literature. Computed tomography showed well demarcated, round densities with tiny calcifications, and mild contrast enhancement (0-25 HU), with no mass effect and with open sulci round the lesion. The angiographical findings were normal except in one patient with an early draining vein and in another with a late draining vein; consequently an injection of at least 10 to 15 ml of contrast medium, and a prolonged angiographical series are recommended. According to the literature, capillary blush may also be seen in angiography. If both CT and angiography are used the diagnosis is definitive, and a neoplasm can be excluded. In five of our patients the diagnosis was verified surgically and histologically, while the sixth patient was not operated on because the frontoparietal lesion was near the motor region. In most cases, surgical removal is easy and successful.
    No preview · Article · Feb 1984 · Acta Neurochirurgica
  • T Kuurne · A Servo · M Porras
    [Show abstract] [Hide abstract]
    ABSTRACT: Three patients shunted for non-tumoural stenosis of the aqueduct suffered from progressive clinical symptoms about four months after the shunting. Computed tomography (CT) showed bilateral subdural effusions. The effusions were evacuated, and the shunts revised. One month later all patients suffered from symptoms of increased intracranial pressure, and CT showed enlargement of the supratentorial cerebral ventricles. The effusions had disappeared. After shunt revision the symptoms decreased again. The fluctuation in the ventricular size, the thickness of the subdural effusions, and the clinical deterioration were related to the change in the opening pressure of the shunt valve in all patients. Patients with large supratentorial cerebral ventricles (Evans index over 0.40) should be monitored by intraventricular pressure recording in order to select the exact opening pressure of the shunt valve before inserting a relieving shunt; a clinical check-up and a CT examination should be carried out about three months after the operation in order to investigate any changes in the function of the shunt.
    No preview · Article · Feb 1983 · Acta Neurochirurgica
  • A Servo · J Jääskinen
    [Show abstract] [Hide abstract]
    ABSTRACT: The venous drainage dynamics of the cavernous sinus were studied by means of 50 carotid angiograms and 18 orbital phlebographies performed on 47 patients with various tumours of the sellar area. Normal blood flow direction in the superior ophthalmic vein (SOV) (from the facial veins into the cavernous sinus) was seen in supra- and small intrasellar tumours, but not in parasellar tumours. In bigger intrasellar tumours and in parasellar tumours the reversed blood flow direction visible in the SOV (from the cavernous sinus into the facial veins) indicated infiltration or compression of the cavernous sinus by tumour. The sign of reversed flow together with CT findings is useful in differential diagnosis and in planning surgical treatment for tumours of the sellar area.
    No preview · Article · Feb 1983 · Acta Neurochirurgica

Publication Stats

753 Citations
71.52 Total Impact Points

Institutions

  • 1978-2001
    • Helsinki University Central Hospital
      • • Department of Neurosurgery
      • • Department of Radiology
      • • Department of Orthopaedics and Traumatology
      Helsinki, Southern Finland Province, Finland
  • 1978-1990
    • University of Helsinki
      • • Department of Neurosurgery
      • • Department of Pathology
      Helsinki, Uusimaa, Finland