Nikolaos Kelekis

ORCID: 0000-0002-8958-4668
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About
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Research Areas
  • Hepatocellular Carcinoma Treatment and Prognosis
  • Spine and Intervertebral Disc Pathology
  • MRI in cancer diagnosis
  • Spinal Fractures and Fixation Techniques
  • Advanced MRI Techniques and Applications
  • Advanced Neuroimaging Techniques and Applications
  • Liver Disease Diagnosis and Treatment
  • Advanced Radiotherapy Techniques
  • Radiation Dose and Imaging
  • Cardiac Imaging and Diagnostics
  • Cholangiocarcinoma and Gallbladder Cancer Studies
  • Functional Brain Connectivity Studies
  • Medical Imaging and Pathology Studies
  • Sarcoidosis and Beryllium Toxicity Research
  • Radiomics and Machine Learning in Medical Imaging
  • Management of metastatic bone disease
  • Renal cell carcinoma treatment
  • Lung Cancer Diagnosis and Treatment
  • Pancreatic and Hepatic Oncology Research
  • Sarcoma Diagnosis and Treatment
  • Gallbladder and Bile Duct Disorders
  • Advanced X-ray and CT Imaging
  • Amyotrophic Lateral Sclerosis Research
  • Musculoskeletal pain and rehabilitation
  • Bone Tumor Diagnosis and Treatments

National and Kapodistrian University of Athens
2016-2025

University General Hospital Attikon
2016-2025

Athens Medical Center
2025

Eginition Hospital
2022

Liverpool Women's Hospital
2013

University of Liverpool
2013

Tzaneion General Hospital
2013

Andreas Sygros Hospital
2013

Athens State University
2004-2012

Sismanoglio General Hospital
2004

Abstract Objective To assess the prevalence and pattern of myocardial fibrosis as detected by delayed enhanced magnetic resonance imaging (DE‐MRI) in patients with systemic sclerosis (SSc), to evaluate a possible association between cardiac arrhythmias. Methods Forty‐one SSc underwent 24‐hour Holter monitoring, Doppler echocardiography, DE‐MRI following gadolinium administration. Results Technically acceptable DE‐MRIs were obtained 36 SSc. Enhancement on DE‐MRI, consistent fibrosis, was...

10.1002/art.22971 article EN Arthritis & Rheumatism 2007-10-29

HASTE (Half fourier Single-shot Turbo spin-Echo) is a single-section T2-weighted sequence that acquires images in less than 1 second. Images are breathing independent and possess variety of other features useful for imaging the abdomen. The design this technique described. Clinical studies 38 consecutive patients were performed using technique. considered good 28 fair 10 patients, including five who could not suspend respiration. Definition liver bowel was particularly clear.

10.1002/jmri.1880060420 article EN Journal of Magnetic Resonance Imaging 1996-07-01

The aim of this study was to determine occupational dose levels in interventional radiology and cardiology procedures.The covered a sample 25 procedures monitored for all laboratory personnel. Each individual wore eight thermoluminescent dosemeters next the eyes, wrists, fingers legs during each procedure. Radiation protection shields used procedure were recorded.The highest doses per recorded interventionists at left wrist (average 485 μSv, maximum 5239 μSv) finger 324 2877 μSv), whereas...

10.1259/bjr/83222759 article EN British Journal of Radiology 2010-12-20

The blood-brain barrier is a major obstacle for the chemotherapeutic drugs to effectively reach primary or secondary brain tumours. Stealth liposomal are highly accumulated in tumoural tissues. In present study we investigated relative accumulation of(99m)Tc-DTPA radiolabelled stealth doxorubicin (Caelyx) 10 patients with metastatic tumours and five glioblastoma undergoing radiotherapy. Patients lesions were treated consecutive fractions of radiotherapy (whole brain, 3 Gy/fraction, day 1-12)...

10.1054/bjoc.2000.1459 article EN cc-by-nc-sa British Journal of Cancer 2000-11-01

The purpose of this study was to define the common appearances hepatocellular carcinoma (HCC) in patients North America by analyzing T1-weighted, T2-weighted, and serial gadolinium-enhanced gradient-echo images interpreted radiologists at multiple institutions America. One hundred thirteen consecutive with HCC from eight were included retrospective case series. Inclusion criteria MR imaging examinations performed on 1.5-T imagers using T1-weighted breath-hold spoiled images, T2-weighted...

10.2214/ajr.170.4.9530051 article EN American Journal of Roentgenology 1998-04-01

Hepatosplenic fungal disease: diagnostic accuracy and spectrum of appearances on MR imaging.R C Semelka, N L Kelekis, S Sallah, Worawattanakul M AscherAudio Available | Share

10.2214/ajr.169.5.9353448 article EN American Journal of Roentgenology 1997-11-01

Abstract This study compares liver lesion detection, characterization, and effect on patient management between single‐phase spiral CT MRI using spoiled gradient echo (SGE), T2‐weighted fat‐suppressed spin echo, serial post gadolinium SGE. All patients with suspected lesions who underwent within a 1‐month period January 1993 September 1996 were included in the study. Spiral interpreted prospectively blinded fashion by separate individual experienced investigators, detection characterization...

10.1002/jmri.1880070616 article EN Journal of Magnetic Resonance Imaging 1997-11-01

Abstract Purpose To investigate the correlation between degree of hepatic, splenic, pancreatic, vertebral bone marrow (VBM), and myocardial siderosis, as expressed by relaxation rate (R2 = 1/T2) values, in patients with thalassemia. Materials Methods R2 values liver, spleen, VBM, pancreas, myocardium were estimated 68 consecutive transfusion‐dependent β‐thalassemia major 10 healthy controls using a respiratory triggered 16‐echo Carr‐Purcell‐Meiboom‐Gill (CPMG) spin echo sequence. Results...

10.1002/jmri.21707 article EN Journal of Magnetic Resonance Imaging 2009-03-20

This study demonstrates the appearance of small bowel tumors on MR images. Sixteen patients with involving were studied by MRI. All proven histopathology. Eleven had primary bowel, which included following: four carcinoid tumors, three adenocarcinomas, two lymphomas, one leiomyosarcoma, and leiomyoma. Five recurrent or metastatic disease to bowel: colon cancer, patient pancreatic uterine chloroma (leukemia). examination breath-hold T1-weighted spoiled gradient echo (all patients), immediate...

10.1002/jmri.1880060603 article EN Journal of Magnetic Resonance Imaging 1996-11-01

The purpose of this article is to present serial clinical and imaging findings for the "absent" pulmonary artery. Data from six patients with condition (five unilateral cases one bilateral case) provide evidence concerning its embryology illustrate therapeutic implications surgical intervention.In our series, we found anatomy absent artery be consistent a distal ductal origin involution proximal sixth aortic arch. distinct embryologic entity that requires early detection detailed...

10.2214/ajr.179.5.1791253 article EN American Journal of Roentgenology 2002-11-01

Abstract Purpose To evaluate the usefulness of a time‐efficient MRI method for quantitative determination tissue iron in liver and heart β‐thalassemic patients using spin‐spin relaxation rate, R2, measurements. Materials Methods Images were obtained at 1.5 T from aqueous Gd‐DTPA solutions (0.106–8 mM) 46 10 controls. The imaging sequence used was respiratory‐triggered 16‐echo Carr‐Purcell‐Meiboom‐Gill (CPMG) spin‐echo (SE) pulse (TR = 2000 msec, TE min 5 echo spacing (ES) matrix 192 × 256,...

10.1002/jmri.20489 article EN Journal of Magnetic Resonance Imaging 2005-12-22

Abstract Our purpose was to identify the histologic types of malignant liver lesions with high signal intensity (SI) on T1‐weighted images and describe MR imaging features. Thirteen patients in SI were studied a 1.5‐T imager using pre‐ serial postcontrast spoiled gradient‐echo (SGE) sequences (all patients), T2‐weighted fat‐suppressed spin‐echo precontrast (five studies five out‐of‐phase SGE (seven six patients). Images reviewed retrospectively determine number lesions; lesion size;...

10.1002/jmri.1880060206 article EN Journal of Magnetic Resonance Imaging 1996-03-01

Computed tomography (CT) coronary angiography has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but high radiation doses have reported. Prospective ECG-gating using a 'step-and-shoot' axial scanning protocol shown to reduce exposure effectively while maintaining diagnostic accuracy. 256-slice with 80 mm detector coverage currently introduced into practice, their impact on not adequately studied. The aim this study was assess associated scanner....

10.1088/0031-9155/54/17/009 article EN Physics in Medicine and Biology 2009-08-11
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