Publications by authors named "Mehmet Yasir Pektezel"

10 Publications

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Intracerebral hemorrhage volume estimation: Is modification of the ABC/2 formula necessary according to the hematoma shape?

Clin Neurol Neurosurg 2021 Jun 24;207:106779. Epub 2021 Jun 24.

HacettepeUniversity Hospitals, Neurology Department, Neurocritical Care and Stroke Units, Ankara, Turkey. Electronic address:

Objective: We studied the proposal to modify the ABC/2 formula to ABC/3 for irregular-shaped intracerebral hematoma (ICH) volume estimation.

Patients And Methods: The volume of 133 ICHs were estimated with Kwak's (simplified C; all slices with hemorrhage are considered equal), Kothari's (weighted C) and coronal (reformatted C; measuring C directly on coronal reformatted images) ABC/2 methods, and compared with computer-assisted planimetric measurements. The accuracy, precision and correlation of three ABC/2 methods and their ABC/3 modifications were determined in smooth (Barras' group 1 or 2) and irregular (Barras' group 3-5) shaped ICHs.

Results: As the hematoma size increases, the shape becomes irregular. In all hematomas, both smooth (n = 81) and irregular (n = 52) shaped, Kothari's ABC/2 formula provided the closest result to the planimetric measurement, with an underestimation of 1.77 mL, and 10.2% difference on average. Kothari's ABC/2 disclosed the best correlation (Lin's coefficient=0.9622) regardless of ICH shape. When simplified-ABC/2 method was modified as ABC/3, volume estimation accuracy increased (Correlation coefficient increased from 0.838 to 0.915) for irregular hematomas; however, despite this improvement the accuracy remained below the Kothari's ABC/2 (not ABC/3) method. Neither reformatted coronal ABC/2 nor its ABC/3 modification provided any advantage over ABC/x formulas with slice counting.

Conclusion: Kothari's ABC/2 method is a valid method for estimation of ICH volume for both regular and irregular shaped hematomas. Simplified (Kwak's) ABC/2 or coronal ABC/2, or their /3 counterparts do not provide additional advantage.
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http://dx.doi.org/10.1016/j.clineuro.2021.106779DOI Listing
June 2021

Stroke Mechanism in COVID-19 Infection: A Prospective Case-Control Study.

J Stroke Cerebrovasc Dis 2021 Aug 1;30(8):105919. Epub 2021 Jun 1.

Department of Neurology, Hacettepe University Hospitals Turkey.

Background: The characteristics and pathophysiological mechanisms involved in acute ischemic stroke in patients with COVID-19 infection have not been fully clarified. We prospectively studied the phenotypic and etiological features of acute stroke occurring in COVID-19 infection.

Patients & Methods: Within nine months starting from April-2020, the presence of COVID-19 infection was determined by thoracic CT and SARS-CoV-2 PCR in all acute stroke cases managed in a single tertiary center. Consecutive and prospective data on vascular risk factors/comorbidities, in-hospital quality metrics, discharge outcomes, etiological subclassification and blood markers of thrombosis / inflammation were compared in 44 COVID-19 positive cases (37 acute ischemic stroke, 5 TIA, 2 intracerebral hematoma) and 509 COVID-19 negative patients (355 ischemic, 105 TIA, 44 hematoma and 5 stroke mimic).

Results: COVID-19 positive patients had more severe strokes, delayed hospital admission, longer hospital stay, higher mortality rates, but had similar vascular risk factors/comorbidities frequency, thrombolysis/thrombectomy utilization rates, metrics, and stroke etiological subtype. They had significantly higher CRP, fibrinogen, ferritin, leukocyte count and lower lymphocyte count. No difference was detected in aPTT, INR, D-dimer, platelet, hemoglobin, homocysteine levels and ANA, anti-dsDNA antibody and ENA panel positivity rates. Anti-phospholipid antibodies have been studied in 70% of COVID-19 positive and all cryptogenic patients, but were never found positive. Tests for coagulation factor levels and hereditary thrombophilia did not show major thrombophilia in any of the stroke patients with COVID-19.

Conclusion: We documented that there is no significant difference in etiological spectrum in acute stroke patients with COVID-19 infection. In addition, cryptogenic stroke and antiphospholipid antibody positivity rates did not increase.
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http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2021.105919DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8166511PMC
August 2021

Carbapenem-resistant Klebsiella pneumoniae meningitis and abscess treated with ceftazidime-avibactam.

Enferm Infecc Microbiol Clin (Engl Ed) 2021 Apr 12. Epub 2021 Apr 12.

Hacettepe University Medical Faculty Department of Infectious Diseases and Clinical Microbiology, Turkey.

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http://dx.doi.org/10.1016/j.eimc.2021.03.014DOI Listing
April 2021

Intracerebral hematoma expansion and intracranial internal carotid artery calcifications.

Clin Neurol Neurosurg 2021 01 12;200:106361. Epub 2020 Nov 12.

Hacettepe University School of Medicine Department of Neurology, Ankara, Turkey. Electronic address:

Background And Aims: Prediction of intracerebral hematoma expansion (IHE) is of critical importance during intracerebral hemorrhage (ICH) management. Given its suggested positive connection with cerebral microvascular disease status, intracranial internal carotid artery wall calcifications (ICAC) on admission computed tomography (CT) studies may contribute to prediction of IHE.

Method: Presence, burden and type [as per Kockelkoren's score] of ICAC were defined in admission CT and CT-angiography of 201 ICH patients [mean age: 70 ± 13 years, 44 % female]. A Kockelkoren's score of <7 indicated intimal calcification [iICAC], while ≥7 indicated non-intimal [or medial] ones [mICAC]. IHE criteria were absolute volume increase of ≥12.5cc or ≥6cc, and relative increase ≥33 % or ≥26 %.

Result: ICAC was diagnosed in 79.6 % of ICH patients. ICAC status was not independent indicator of milder IHE (≥6cc and ≥26 % IHE, both in 27 %). Presence of contralateral mICAC was found to be an independent predictor for higher grade IHE (expβ = 3.44, 95 %CI: 1.47-8.04, for IHE ≥ 12.5cc, diagnosed in 14.4 %; and expβ = 2.67, 95 %CI: 1.29-5.55, for IHE ≥ 33 %, diagnosed in 24 %). Mortality (31 %) was higher in those with ipsilateral any type ICAC (36 % in mICAC, 38 % in iICAC, 17 % in no ICAC, p = 0.017), but this was not independent predictor in logistic regression. Similarly, medial ICAC in both ipsilateral (47 % vs. 31 %, p = 0.037) and contralateral (47 % vs. 30 %, p = 0.017) sides was associated with poorer prognosis (42 %) on univariate, but not multivariate analysis.

Conclusion: Intracranial ICA calcification is highly prevalent in ICH. mICAC may be associated with risk of "high amount" acute hematoma expansion, hospital mortality and poor prognosis.
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http://dx.doi.org/10.1016/j.clineuro.2020.106361DOI Listing
January 2021

Systemic Inflammation Indices in Patients With Acute Ischemic Stroke Treated With Intravenous Tissue Plasminogen Activator: Clinical Yield and Utility.

Angiology 2021 03 6;72(3):279-284. Epub 2020 Nov 6.

Department of Neurology and Neurological Intensive Care Unit, 64005Hacettepe University Hospitals, Sihhiye, Ankara, Turkey.

Inflammation indices derived from complete blood counts (CBCs) have been proposed to estimate benefit and risk of intravenous (IV) tissue plasminogen activator (tPA) in acute ischemic stroke. In 165 acute ischemic patients, the neutrophil-to-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio, and systemic immune-inflammation index (SII) were calculated before and 24 hours after IV tPA. The area under receiver operating characteristic (AUC-ROC) curves, and positive and negative likelihood ratios (+LR,-LR) were produced to measure their diagnostic accuracy and clinical utility for tPA effectiveness, hemorrhage risk and third-month prognosis. None of the indices obtained "before" IV-tPA was found to be useful in determining acute and long-term functional efficacy and bleeding risk. Lymphocyte decrease, neutrophil increase, and parallel NLR and SII increase at the 24th-hour were associated with poor functional outcome. However, their clinical utility was not sufficient due to absence of effective thresholds. NLR threshold >5.65 provided ROC-AUC 0.86, sensitivity 71.3%, specificity 65.7%, -LR 0, +LR 3.76, and SII threshold >1781 had ROC-AUC 0.802, sensitivity 58.7%, specificity 72.7%, -LR 0.11, +LR 4.52, corresponding to an acceptable clinical yield. Systemic immune-inflammation index and NLR, but not other CBC-derived inflammatory parameters, have moderate utility as marker of tPA-related symptomatic hemorrhage occurrence.
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http://dx.doi.org/10.1177/0003319720969997DOI Listing
March 2021

Isolated Sulcal Effacement and Response to Intravenous Thrombolysis in Acute Ischemic Stroke.

J Stroke Cerebrovasc Dis 2020 Oct 29;29(10):105168. Epub 2020 Jul 29.

Hacettepe University Hospitals, Neurology Department, Stroke Unit, Ankara, Turkey. Electronic address:

Background And Purpose: Isolated Sulcal Effacement (ISE) is focal cortical swelling without obscuration of cortical gray-white junction. The available information on its role in acute stroke patients treated with intravenous (IV) tissue plasminogen activator (tPA) is limited.

Methods: ISE along with ASPECT and rLMC collateral score were determined in pre-treatment CT/CT angiography of 195 consecutive acute stroke patients treated with IV tPA "only". In addition, ISE-ASPECT score was created. Role of ISE on responsiveness to IV tPA, thrombolysis-associated hemorrhage and functional outcome were studied in 102 patients with CT-angiography-confirmed anterior system proximal vessel occlusion.

Results: ISE was observed in 12 patients (6.2% of all and 11.4% of those with occlusion of the carotid terminus, M1, or proximal M2) corresponding to excellent specificity (100%) but fair sensitivity (12%) for diagnosis of anterior cerebral circulation proximal artery occlusion. ISE ASPECT score was significantly correlated with rLMC score (p=0.023). Presence of ISE was linked to younger age, female gender, lower NIHSS, along with higher ASPECT and rLMC scores. Albeit not persisted after adjustment for collateral status and NIHSS, dramatic response to IV tPA along with excellent (23% vs. 8%, p<0.05), good (21% vs. 6%, p<0.05) and acceptable (19% vs. 4%, p<0.05) functional outcome were significantly higher in patients with ISE.

Conclusions: As a plain CT marker of sufficient collateral status and increased cerebral blood volume, ISE indicates a better response to IV tPA. However, it should be noted that this relatively rare CT finding is highly specific for cerebral large vessel occlusions amenable neurothrombectomy.
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http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2020.105168DOI Listing
October 2020

The determinants of neurological phenotypes during acute hypertensive crises - a preliminary study.

Neurol Res 2020 May 2;42(5):398-404. Epub 2020 Mar 2.

Department of Neurology, Hacettepe University, Ankara, Turkey.

: Acute blood pressure elevations lead to wide spectrum of neurologic manifestations, ranging from no overt neurologic symptoms to catastrophic events like ICH. Little is known regarding the determinants of this clinical variability. We determined clinical and imaging features of hypertensive crisis patients with normal neurological examination, ICH and posterior reversible encephalopathy syndrome (PRES).: Cranial MRI was performed in patients with hypertensive urgency or emergency but normal neurological examination. Their clinical characteristics, and imaging features regarding cerebral small vessel disease were compared to ICH and PRES patients.: Hypertensive ICH patients (n = 58) were older, less likely to have hyperlipidemia, less commonly used calcium channel blockers, and had higher burden of chronic cSVD features in comparison to hypertensive crisis patients with normal neurological findings (n = 51). Multivariate analyses revealed cSVD burden score (p = 0.003) to be related with ICH, while higher admission blood pressure levels (p < 0.001), hyperlipidemia (p = 0.006) and calcium channel blocker usage (p = 0.005) were more common in patients with normal neurological examination. The PRES (n = 9) group was comprised of younger patients with recent history of hypertension and low burden of cSVD.: Hypertensive surge is associated with ICH when cSVD burden is high, probably caused by microvascular dysfunction secondary to long-standing hypertension, while the episode causes no structural damage if this burden is less. Although our observations are exploratory, short term but severe hypertension manifests with PRES possibly due to the absence of adaptive changes.
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http://dx.doi.org/10.1080/01616412.2020.1735121DOI Listing
May 2020

Paradoxical consequence of human chorionic gonadotropin misuse.

J Stroke Cerebrovasc Dis 2015 Jan 8;24(1):e17-9. Epub 2014 Nov 8.

Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey. Electronic address:

Recombinant human chorionic gonadotropin (hCG) is commonly misused as a weight reducing or performance enhancing agent but is associated with increased risk of thromboembolic events. A 29-year-old female with a history of obesity was admitted to our center with a diagnosis of ischemic stroke. Etiologic workup revealed a large patent foramen ovale and history of recent use of hCG as part of a weight loss regimen. This report highlights the potential complications of hCG therapy, particularly when used for unapproved indications and without medical supervision.
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http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2014.08.010DOI Listing
January 2015

Unusual presentation of hypothalamic hamartoma with hypersomnia in an adult patient.

Epileptic Disord 2014 Sep;16(3):366-9

Department of Neurology.

We report a patient with polysomnography findings related to hypersomnia, as a primary presenting symptom, who was shown to have stereotypical gelastic seizures. Her cranial magnetic resonance imaging revealed a hypothalamic hamartoma in the posterior region of the hypothalamus. The patient had no previous history of gelastic seizures. We suggest that patients who present with hypersomnia should be investigated for gelastic seizures in order to avoid misdiagnosis and receive appropriate treatment.
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http://dx.doi.org/10.1684/epd.2014.0669DOI Listing
September 2014
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