Browsing by Author "Öz, DK"

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    Quantitative liver magnetic resonance imaging: correlation between conventional magnetic resonance imaging, laboratory values, and prognostic indices in Budd-Ch iari syndrome
    Erden, A; Öz, DK; Adigüzel, M; Ates, FSO
    PURPOSE In Budd-Chiari syndrome (BCS), unevenly distributed parenchymal changes and perfusion abnor-malities occur due to hepatic venous outflow obstruction. This study aimed to evaluate the changes in the liver parenchyma in BCS using the quantitative magnetic resonance (MR) techniques of MR elastography, T1 and T2 mapping, and diffusion imaging and correlate the quantitative MR param-eters through biochemical results and prognostic indices. METHODS Fourteen patients with BCS (seven men and seven women) were examined retrospectively. Liver stiffness (kPa), T1 relaxation times (ms) were achieved using the modified Look-Locker inversion recovery (MOLLI) 3(2)3(2)5 sequence and B1-corrected variable flip angle methods, T2 relaxation times (ms), and apparent diffusion coefficient (ADC) values (mm2/s) were measured using regions of interest placed in the same region in all quantitative methods. Measurements were repeated at the precontrast and postcontrast hepatobiliary phases. The reduction rate (RR; %) and adjusted post -contrast T1 (%) were calculated. The values obtained from different liver parenchyma areas (whole liver, caudate lobe, pathological T2 hyperintense tissue, and relatively preserved normal-appearing tissue) were compared using the Wilcoxon signed-rank test. Spearman's correlation coefficient was used to investigate the correlation between quantitative MR parameters and biochemical parame-ters/prognostic scores (Child-Pugh score, Clichy score, and Rotterdam index). RESULTS The parenchymal stiffness and precontrast T1 values of the caudate lobe were significantly lower than those of the remainder of the parenchyma, whereas the adjusted postcontrast T1 percentages (MOLLI) were significantly higher (P & LE; 0.027). The parenchymal stiffness value, T1 and T2 values, percentages of RR (MOLLI), and adjusted postcontrast T1 values for the pathological tissue and relatively normal tissue were significantly different (P < 0.028). No significant difference was found in terms of ADC values between any of the distinct regions of the liver. A strong correlation was detected between the Child-Pugh score, Clichy score, and precontrast T1 values obtained through the MOLLI sequence (r = 0.867, P = 0.012, r = 0.821, P = 0.023, respectively). No correlation was found between the whole liver stiffness values and the laboratory parameters, fibrosis markers, prognostic indices, or MR parameters. A significant correlation was identified be-tween creatinine levels and several T1 parameters and the T2 relaxation time (r & GE; 0.661, P & LE; 0.052). CONCLUSION Tissue stiffness and T1 relaxation values are high in the areas identified as fibrosis compared with those in the relatively preserved parenchyma. The T1 relaxation time can offer quantitative informa-tion for assessing segmental functional changes and prognosis in BCS.
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    Biphasic split-bolus injection protocol for routine contrast-enhanced chest CT: comparison with conventional early-phase single bolus technique
    Kul, M; Öz, DK; Coruh, AG; Ates, FÖ; Gülpinar, B; Uzun, Ç; Atasoy, KÇ
    Objectives: To present a routine contrast-enhanced chest CT protocol with a split-bolus injection technique achieving combined early- and delayed phase images with a single aquisition, and to compare this technique with a conventional early-phase single-bolus chest CT protocol we formerly used at our institution, in terms of attenuation of great thoracic vessels, pleura, included hepatic and portal venous enhancement, contrast-related artifacts, and image quality. Methods: A total of 202 patients, who underwent routine contrast-enhanced chest CT examination aquired with either conventional early-phase single-bolus technique (group A,n = 102) or biphasic split-bolus protocol (group B,n = 100), were retrospectively included. Attenuation measurements were made by two radiologists independently on mediastinal window settings using a circular ROI at the following sites: main pulmonary artery (PA) at its bifurcation level, thoracal aorta (TA) at the level of MPA bifurcation,portal vein ( PV) at porta hepatis, left and right hepatic lobe, and if present, thickened pleura (>2 mm) at the level with the most intense enhancement. Respective normalized enhancement values were also calculated. Contrast-related artifacts were graded and qualitative evaluation of mediastinal lymph nodes was performed by both reviewers independently. Background noise was measured and contrast-to-noise ratios (CNRs) of the liver and TA were calculated. Results: While enhancement of thoracic vessels and normalised MPA enhancement did not differ significantly between both groups (p > 0.05), enhancement and normalised enhancement of pleura, liver parenchyma and PV was significantly greater in group B (p < 0.001). Perivenous artifacts limiting evaluation were less frequent in group B than in A and mediastinal lymph nodes were judged to be evaluated worse in group A than in group B with an excellent agreement between both observers. No significant difference was detected in CNRTA (p = 0.633), whereas CNR liver was higher in group B (p < 0.001). Conclusion: Our split-bolus chest CT injection protocol enables simultaneous enhancement for both vascular structures and soft tissues, and thus, might raise diagnostic confidence without the need of multiple acquisitions. Advances in knowledge: We think that this CT protocol might also be a promising alternative in lung cancer staging, where combined contrast-enhanced CT of the chest and abdomen is indicated. We therefore suggest to further evaluate its diagnostic utility in this setting, in particular in comparison with a late delayed ches--upper abdominal CT imaging protocol.
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    Evaluation of abdominal computed tomography findings in patients with COVID-19: a multicenter study
    Onur, MR; Özbay, Y; Idilman, I; Karaosmanoglu, AD; Ramadan, SU; Barlik, F; Aydin, S; Odaman, H; Altay, C; Akin, IB; Dicle, O; Appak, O; Gülpinar, B; Erden, A; Kula, S; Çoruh, AG; Öz, DK; Kul, M; Uzun, C; Karavas, E; Levent, A; Artas, H; Eryesil, H; Solmaz, O; Kaygusuz, TO; Farasat, M; Kale, AB; Düzgün, F; Pekindil, G; Apaydin, FD; Duce, MN; Balci, Y; Esen, K; Kahraman, AS; Karaca, L; Özdemir, ZM; Kahraman, B; Tosun, M; Nural, MS; Camlidag, I; Onar, MA; Balli, K; Güler, E; Harman, M; Elmas, NZ; Öztürk, C; Güngör, O; Herek, D; Yagci, AB; Erol, C; Seker, M; Islek, I; Can, Y; Aslan, S; Bilgili, MYK; Göncüoglu, A; Keles, H; Sarikaya, PZB; Bakir, B; Kartal, MGD; Durak, G; Oguzdogan, GY; Alper, F; Yalçin, A; Gürel, S; Alan, B; Gündogdu, E; Aydin, N; Cansu, A; Kus, CC; Tuncer, EO; Piskin, FC; Er, HC; Degirmenci, B; Özmen, MN; Kantarci, M; Karçaaltincaba, M
    PURPOSETo evaluate the frequency of abdominal computed tomography (CT) findings in patients with coronavirus disease-2019 (COVID-19) and interrogate the relationship between abdominal CT findings and patient demographic features, clinical findings, and laboratory test results as well as the CT atheroscle-rosis score in the abdominal aorta.METHODSThis study was designed as a multicenter retrospective study. The abdominal CT findings of 1.181 patients with positive abdominal symptoms from 26 tertiary medical centers with a positive polymerase chain-reaction test for severe acute respiratory syndrome coronavirus 2 were reviewed. The frequency of ischemic and non-ischemic CT findings as well as the association between CT findings, clinical features, and abdominal aortic calcific atherosclerosis score (AA-CAS) were recorded.RESULTSIschemic and non-ischemic abdominal CT findings were detected in 240 (20.3%) and 328 (27.7%) patients, respectively. In 147 patients (12.4%), intra-ab-dominal malignancy was present. The most frequent ischemic abdominal CT findings were bowel wall thickening (n = 120; 10.2%) and perivascular infil-tration (n = 40; 3.4%). As for non-ischemic findings, colitis (n = 91; 7.7%) and small bowel inflammation (n = 73; 6.2%) constituted the most frequent disease processes. The duration of hospital stay was found to be higher in patients with abdominal CT findings than in patients without any positive findings (13.8 & PLUSMN; 13 vs. 10.4 & PLUSMN; 12.8 days, P < 0.001). The frequency of abdominal CT findings was significantly higher in patients who did not survive the infection than in patients who were discharged after recovery (41.7% vs. 27.4%, P < 0.001). Increased AA-CAS was found to be associated with a higher risk of ischemic conditions in abdominal CT examinations.CONCLUSIONAbdominal symptoms in patients with COVID-19 are usually associated with positive CT findings. The presence of ischemic findings on CT correlates with poor COVID-19 outcomes. A high AA-CAS is associated with abdominal ischemic findings in patients with COVID-19.