Browsing by Author "Kovač, Jelena Djokić (52563972900)"

Background: Pancreatic adenocarcinoma is a highly lethal disease even in initially resectable patients. Functional imaging procedures such as diffusion-weighted imaging (DWI) and computed tomography (CT)-perfusion might facilitate preoperative prediction of factors influencing prognosis in patients with pancreatic adenocarcinoma. Purpose: To evaluate CT-perfusion and DWI quantitative parameters of pancreatic adenocarcinoma and to assess their correlation with clinicopathological features. Material and Methods: Forty-four patients with histopathologically proven pancreatic adenocarcinoma underwent CT-perfusion and DWI for estimating blood volume (BV), blood perfusion (BF), mean transit time (MTT), time to peak (TTP), and apparent diffusion coefficient (ADC) values. The statistical analysis was performed using Wilcoxon matched-pairs test, t-test for independent samples, Spearman’s rank correlation coefficient (rs), and receiver operating characteristic analysis. Results: The mean CT-perfusion parameters and ADCs were significantly different in pancreatic adenocarcinoma versus healthy parenchyma. BV (2.66 ± 0.98 mL/100g), BF (17.45 ± 4.06 mL/min/100g), and ADCs (0.91 ± 0.15 × 10−3mm/s2) in high-grade tumors were significantly lower in comparison to low-grade tumors (BV = 5.35 ± 1.36 mL/100g, BF = 28.51 ± 7.73 mL/min/100g, ADC = 1.07 ± 0.21 × 10−3mm/s2). For prediction of high-grade tumors, the sensitivity and specificity were 79.2% and 82.4% for BF and 87.5% and 88.2% for BV, respectively. A significant negative correlation was found between BV and tumor size (rs = −0.445, P = 0.029), MTT and tumor size (rs = −0.330, P = 0.043), BV and M-stage (rs = −0.286, P = 0.049), and ADC and M-stage (rs = −0.274, P = 0.038). Moreover, BF and BV values were significantly associated with ADCs. Conclusion: CT-perfusion parameters and ADC values could improve preoperative assessment of pancreatic adenocarcinoma with possibility of tumor grade prediction. © The Foundation Acta Radiologica 2018.

Background: Pancreatic adenocarcinoma is a highly lethal disease even in initially resectable patients. Functional imaging procedures such as diffusion-weighted imaging (DWI) and computed tomography (CT)-perfusion might facilitate preoperative prediction of factors influencing prognosis in patients with pancreatic adenocarcinoma. Purpose: To evaluate CT-perfusion and DWI quantitative parameters of pancreatic adenocarcinoma and to assess their correlation with clinicopathological features. Material and Methods: Forty-four patients with histopathologically proven pancreatic adenocarcinoma underwent CT-perfusion and DWI for estimating blood volume (BV), blood perfusion (BF), mean transit time (MTT), time to peak (TTP), and apparent diffusion coefficient (ADC) values. The statistical analysis was performed using Wilcoxon matched-pairs test, t-test for independent samples, Spearman’s rank correlation coefficient (rs), and receiver operating characteristic analysis. Results: The mean CT-perfusion parameters and ADCs were significantly different in pancreatic adenocarcinoma versus healthy parenchyma. BV (2.66 ± 0.98 mL/100g), BF (17.45 ± 4.06 mL/min/100g), and ADCs (0.91 ± 0.15 × 10−3mm/s2) in high-grade tumors were significantly lower in comparison to low-grade tumors (BV = 5.35 ± 1.36 mL/100g, BF = 28.51 ± 7.73 mL/min/100g, ADC = 1.07 ± 0.21 × 10−3mm/s2). For prediction of high-grade tumors, the sensitivity and specificity were 79.2% and 82.4% for BF and 87.5% and 88.2% for BV, respectively. A significant negative correlation was found between BV and tumor size (rs = −0.445, P = 0.029), MTT and tumor size (rs = −0.330, P = 0.043), BV and M-stage (rs = −0.286, P = 0.049), and ADC and M-stage (rs = −0.274, P = 0.038). Moreover, BF and BV values were significantly associated with ADCs. Conclusion: CT-perfusion parameters and ADC values could improve preoperative assessment of pancreatic adenocarcinoma with possibility of tumor grade prediction. © The Foundation Acta Radiologica 2018.

Background: Computational analysis of routinely acquired MRI has potential to improve the tumor chemoresistance prediction and to provide decision support in precision medicine, which may extend patient survival. Most radiomic analytical methods are compatible only with rectangular regions of interest (ROIs) and irregular tumor shape is therefore an important limitation. Furthermore, the currently used analytical methods are not directionally sensitive. Purpose: To implement a tumor analysis that is directionally sensitive and compatible with irregularly shaped ROIs. Study Type: Retrospective. Subjects: A total of 54 patients with histopathologic diagnosis of primary osteosarcoma on tubular long bones and with prechemotherapy MRI. Field Strength/Sequence: A 1.5 T, T2-weighted-short-tau-inversion-recovery-fast-spin-echo. Assessment: A model to explore associations with osteosarcoma chemo-responsiveness included MRI data obtained before OsteoSa MAP neoadjuvant cytotoxic chemotherapy. Osteosarcoma morphology was analyzed in the MRI data by calculation of the nondirectional two-dimensional (2D) and directional and nondirectional one-dimensional (1D) Higuchi dimensions (Dh). MAP chemotherapy response was assessed by histopathological necrosis. Statistical Tests: The area under the receiver operating characteristic (ROC) curve (AUC) evaluated the association of the calculated features with the actual chemoresponsiveness, using tumor histopathological necrosis (95%) as the endpoint. Least absolute shrinkage and selection operator (LASSO) machine learning and multivariable regression were used for feature selection. Significance was set at <0.05. Results: The nondirectional 1D Dh reached an AUC of 0.88 in association with the 95% tumor necrosis, while the directional 1D analysis along 180 radial lines significantly improved this association according to the Hanley/McNeil test, reaching an AUC of 0.95. The model defined by variable selection using LASSO reached an AUC of 0.98. The directional analysis showed an optimal predictive range between 90° and 97° and revealed structural osteosarcoma anisotropy manifested by its directionally dependent textural properties. Data Conclusion: Directionally sensitive radiomics had superior predictive performance in comparison to the standard nondirectional image analysis algorithms with AUCs reaching 0.95 and full compatibility with irregularly shaped ROIs. Evidence Level: 3. Technical Efficacy: Stage 1. © 2022 International Society for Magnetic Resonance in Medicine.

Objectives: To evaluate magnetic resonance imaging (MRI) findings in patients with primary biliary cirrhosis (PBC) and to determine the value of diffusion-weighted imaging (DWI) in the assessment of liver fibrosis. Materials and methods: The following MRI findings were reviewed in 44 patients: periportal T2-weighted hyperintensity, periportal halo sign (T1- and T2-weighted periportal hypointensity), lymphadenopathy, signs of portal hypertension and morphological liver changes. Apparent diffusion coefficient (ADC) was calculated for six locations in the liver for b = 800 s/mm 2. Results: Periportal hyperintensity and periportal halo sign were observed in 72.7% and 66.7% of patients, respectively. Lymphadenopathy was noted in 28 patients (63.6%) and diffuse hepatomegaly in 18 (40.9%). Significant positive correlation was observed between histological stage and periportal halo sign (p = 0.613), hepatomegaly (p = 0.443), and portosystemic collaterals (p = 0.391). The mean ADCs (×10 -3 mm 2/s) were significantly different at stage I versus III and IV, and stage II versus IV. No significant difference was found between stages II and III. For prediction of stage ≥ II and stage ≥ III areas under receiver operating characteristic curves were 0.879 and 0.906, respectively. Conclusion: MRI with DWI could be used as a part of diagnostic protocol in the further evaluation of PBC patients providing noninvasive assessment of liver fibrosis progression. Key Points : • MRI provides insight into the morphological liver changes in primary biliary cirrhosis (PBC) • The periportal "halo" sign is a highly specific finding in PBC • Diffusion-weighted MR imaging allows noninvasive assessment of liver fibrosis grade © 2011 European Society of Radiology.

Background: Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose: To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods: Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion (b = 800 s/mm2). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results: Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion: Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions. © 2017, © The Foundation Acta Radiologica 2017.

Background: Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose: To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods: Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion (b = 800 s/mm2). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results: Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion: Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions. © 2017, © The Foundation Acta Radiologica 2017.

65-year-old man was evaluated because of vomiting and epigastric pain. The patient underwent upper gastrointestinal endoscopy and endoscopic ultrasound examination and was found to have multiple polypoid lesions in the D1 and D2 portions of the duodenum, causing almost complete obstruction of the duodenal lumen. The lesions were hyperintense on T1-weighted and intermediately intense on T2-weighted images, with a drop in signal on T1- and T2-weighted fat-suppressed images, consistent with a diagnosis of duodenal lipomas. Pathohistological examination confirmed the diagnosis of duodenal lipomas. © Japan Radiological Society 2012.

Background: Primary sclerosing cholangitis (PSC) is a cholestatic liver disease with chronic inflammation and progressive destruction of biliary tree. Magnetic resonance (MR) examination with diffusion-weighted imaging (DWI) allows analysis of morphological liver parenchymal changes and non-invasive assessment of liver fibrosis. Moreover, MR cholangiopancreatography (MRCP), as a part of standard MR protocol, provides insight into bile duct irregularities. Purpose: To evaluate MR and MRCP findings in patients with primary sclerosing cholangitis and to determine the value of DWI in the assessment of liver fibrosis. Material and Methods: The following MR findings were reviewed in 38 patients: abnormalities in liver parenchyma signal intensity, changes in liver morphology, lymphadenopathy, signs of portal hypertension, and irregularities of intra- and extrahepatic bile ducts. Apparent diffusion coefficient (ADC) was calculated for six locations in the liver for b = 800 s/mm2. Results: T2-weighted hyperintensity was seen as peripheral wedge-shaped areas in 42.1% and as periportal edema in 28.9% of patients. Increased enhancement of liver parenchyma on arterial-phase imaging was observed in six (15.8%) patients. Caudate lobe hypertrophy was present in 10 (26.3%), while spherical liver shape was noted in 7.9% of patients. Liver cirrhosis was seen in 34.2% of patients; the most common pattern was micronodular cirrhosis (61.5%). Other findings included lymphadenopathy (28.9%), signs of portal hypertension (36.7%), and bile duct irregularities (78.9%). The mean ADCs (x10-3mm2/s) were significantly different at stage I vs. stages III and IV, and stage II vs. stage IV. No significant difference was found between stages II and III. For prediction of stage ≥II and stage ≥III, areas under receiver-operating characteristic curves were 0.891 and 0.887, respectively. Conclusion: MR with MRCP is a necessary diagnostic procedure for diagnosis of PSC and evaluation of disease severity. Moreover, DWI could be used in continuation with standard MR sequences for the evaluation of liver fibrosis stage and distribution.

Background: Primary sclerosing cholangitis (PSC) is a cholestatic liver disease with chronic inflammation and progressive destruction of biliary tree. Magnetic resonance (MR) examination with diffusion-weighted imaging (DWI) allows analysis of morphological liver parenchymal changes and non-invasive assessment of liver fibrosis. Moreover, MR cholangiopancreatography (MRCP), as a part of standard MR protocol, provides insight into bile duct irregularities. Purpose: To evaluate MR and MRCP findings in patients with primary sclerosing cholangitis and to determine the value of DWI in the assessment of liver fibrosis. Material and Methods: The following MR findings were reviewed in 38 patients: abnormalities in liver parenchyma signal intensity, changes in liver morphology, lymphadenopathy, signs of portal hypertension, and irregularities of intra- and extrahepatic bile ducts. Apparent diffusion coefficient (ADC) was calculated for six locations in the liver for b = 800 s/mm2. Results: T2-weighted hyperintensity was seen as peripheral wedge-shaped areas in 42.1% and as periportal edema in 28.9% of patients. Increased enhancement of liver parenchyma on arterial-phase imaging was observed in six (15.8%) patients. Caudate lobe hypertrophy was present in 10 (26.3%), while spherical liver shape was noted in 7.9% of patients. Liver cirrhosis was seen in 34.2% of patients; the most common pattern was micronodular cirrhosis (61.5%). Other findings included lymphadenopathy (28.9%), signs of portal hypertension (36.7%), and bile duct irregularities (78.9%). The mean ADCs (x10-3mm2/s) were significantly different at stage I vs. stages III and IV, and stage II vs. stage IV. No significant difference was found between stages II and III. For prediction of stage ≥II and stage ≥III, areas under receiver-operating characteristic curves were 0.891 and 0.887, respectively. Conclusion: MR with MRCP is a necessary diagnostic procedure for diagnosis of PSC and evaluation of disease severity. Moreover, DWI could be used in continuation with standard MR sequences for the evaluation of liver fibrosis stage and distribution.

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Primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC) are the most common immunemediated chronic cholestatic liver diseases leading to cirrhosis and liver failure. Although magnetic resonance imaging (MRI) is not a necessary procedure for the diagnosis of PBC, MRI is recommended for monitoring disease progression and early detection of complications. Even though liver cirrhosis subtypes have similar MR imaging features, there are some findings which could indicate PBC, such as the periportal halo sign. Additionally, MRI using diffusion-weighted imaging with apparent diffusion coefficient measurements provides non-invasive assessment of the stage of liver fibrosis. The role of cholangiography is crucial for the diagnosis of PSC. Since endoscopic retrograde cholangiography is an invasive procedure with occasional post-procedural complications, the latest guidelines suggest magnetic resonance cholangiography as a reference procedure for evaluation of patients suspected with PSC. Characteristic magnetic resonance cholangiography findings include multiple segmental strictures with slightly dilated ducts among them, usually on both intrahepatic and extrahepatic bile ducts. Furthermore, magnetic resonance cholangiography is useful in the follow-up of these patients, allowing for timely diagnosis of complications such as cholangiocellular carcinoma. With the exception of ursodeoxycholic acid, which slows the progression of PBC, the only curative treatment for both PSC and PBC is still liver transplantation. However, recurrent disease occurs in some patients indicating the need for development of new more effective therapies. © 2016, Romanian Society of Gastroenterology. All rights reserved.

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[Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

[Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Rationale and Objectives: To evaluate factors predicting pancreatic cancer recurrence, and to determine the most common appearance of tumor relapse. Materials and Methods: Ninety patients with recurrent pancreatic cancer were retrospectively included in the study. 74.4% had pancreatic head tumors (group 1)and 25.6% pancreatic body and/or tail tumor (group 2). The tumor localization, operative technique, TNM stage, the R-status, tumor grade, lymphovascular, and perineural invasion were recorded. Location of local tumor recurrence, lymph node recurrence, or organ metastases were analyzed on the basis of follow-up CT imaging. Results: Mean recurrence time was 17.4 ± 13.2 months. The most common recurrence type was local recurrence (84.4%), followed by lymph node (15.5%), liver (14.4%), and lung metastasis (6.7%). The predominant site of local recurrence in pancreatic head tumors was close to superior mesenteric artery, common hepatic artery, and/or celiac artery (57.4%), followed by area defined by portal vein, inferior vena cava, CA or superior mesenteric artery (31.2%). Patients with pancreatic body and/or tail carcinoma had higher incidence (p = 0.003)of metastatic disease comparing to pancreatic head tumors, while resection margin was the most common type of local tumor recurrence, seen in 46.7% cases versus 8.2% of patients with pancreatic head tumors (p < 0.001). Conclusion: The most common recurrence type in patients with resected pancreatic carcinoma was local recurrence along cardinal arteries. The localization of primary tumor influences the type of tumor relapse and site of local recurrence. © 2018 The Association of University Radiologists