Papers by Nikolaos Kelekis
Emergency Radiology, 2022
Background Admission chest CT is often included in COVID-19 patient management. Purpose To evalua... more Background Admission chest CT is often included in COVID-19 patient management. Purpose To evaluate the inter-and intraobserver variability of the Covid Visual Assessment Scale ("Co.V.A.Sc.") used for stratifying chest CT disease extent and to estimate its prospect to predict clinical outcomes. Materials and methods This single-center, retrospective observational cohort study included all RT-PCR-confirmed COVID-19 adult patients undergoing admission chest CT, between 01/03/2021 and 17/03/2021. CTs were independently evaluated by two radiologists according to the "Co.V.
Brain Topography, 2022
Previous sMRI, DTI and rs-fMRI studies in small cell lung cancer (SCLC) patients have reported th... more Previous sMRI, DTI and rs-fMRI studies in small cell lung cancer (SCLC) patients have reported that patients after chemotherapy had gray and white matter structural alterations along with functional deficits. Nonetheless, few are known regarding the potential alterations in the topological organization of the WM structural network in SCLC patients after chemotherapy. In this context, the scope of the present study is to evaluate the WM structural network of 20 SCLC patients after chemotherapy and to 14 healthy controls, by applying a combination of DTI with graph theory. The results revealed that both SCLC and healthy controls groups demonstrated small world properties. The SCLC patients had decreased values in the clustering coefficient, local efficiency and degree metrics as well as increased shortest path length when compared to the healthy controls. Moreover, the two groups reported different topological reorganization of hub distribution. Lastly, the SCLC patients exhibited significantly decreased structural connectivity in comparison to the healthy group. These results underline that the topological organization of the WM structural network in SCLC patients was disrupted and hence constitute new vital information regarding the effects that chemotherapy and cancer may have in the patients' brain at network level.
Pediatric Cardiology, 2004
The interesting article in Pediatric Cardiology by Fu et al. [3] on the anomalous origin of pulmo... more The interesting article in Pediatric Cardiology by Fu et al. [3] on the anomalous origin of pulmonary artery (PA) from the innominate artery, an entity also termed ''absent'' PA, promotes discussion on several embryology and therapeutic issues. In a study describing six absent PA patients, including one with serial angiographic imaging after birth and another with bilateral absent PAs [1], we analyzed the embryology of this entity as different from that of ''proximal anomalous origin of pulmonary artery from the ascending aorta'' [3]. During embryonic development, the intrapulmonary PA arises from the lung bud and the extrapulmonary PA from the proximal sixth aortic arch, while the distal sixth aortic arch becomes the ductus arteriosus. Involution of the proximal sixth aortic arch (future proximal PA), leading to persistent connection of the intrapulmonary PA to the distal sixth aortic arch (future ductus arteriosus), creates the entity of absent PA. The ductus arteriosus, as for all primitive arches, connects to the primitive dorsal aorta, becoming the underside of the arch when ipsilateral or the base of the innominate artery when contralateral to the arch [7]. This explanation is supported by the literature reporting that all 18 absent PA cases with satisfactory documentation on angiography [1, 4], surgery [5, 6], or autopsy [7] had a ductus arteriosus or ligamentum ipsilateral to the absent PA. Even in the 4 cases with known contralateral ductus arteriosus from the underside of the arch, a ductus arteriosus or ligamentum from the base of the ispilateral innominate artery to the absent PA was discovered on angiography [1, 2, 4] or autopsy [7]; therefore, bilateral ductus arteriosi were present. As delineated previously, a relatively normal intrapulmonary portion of the absent PA originates from the ductus arteriosus. It is not PA stenosis but rather progressive constriction and eventual closure of the ductus arteriosus, obviously responding to prostaglandin, that leads to regression and hypoplasia of the absent PA. Progressive ductus arteriosus constriction and closure was clearly depicted by serial angiography in our study [1]. Surgery was delayed in the second case described [3]. In our series, repair soon after ductus arteriosus closure preserved PA patency, whereas later surgical correction was unsuccessful, possibly due to intrapulmonary PA hypoplasia. Our data are insufficient to draw conclusions; nevertheless, early surgery providing satisfactory antegrade blood flow to the absent PA before hypoplasia is established might improve the chances of successful incorporation of the absent PA into the pulmonary circulation.
Progress in Neuro-Psychopharmacology and Biological Psychiatry, 2021
BACKGROUND The cerebellum has a crucial role in mood regulation. While cerebellar grey matter (GM... more BACKGROUND The cerebellum has a crucial role in mood regulation. While cerebellar grey matter (GM) alterations have been previously reported in bipolar disorder (BD), cerebro-cerebellar white matter (WM) connectivity alterations and cerebellar GM profiles have not been characterised in the context of predominant polarity (PP) and onset polarity (OP) subphenotypes of BD patients which is the aim of the present study. METHODS Forty-two euthymic BD patients stratified for PP and OP and 42 healthy controls (HC) were included in this quantitative neuroimaging study to evaluate cerebellar GM patterns and cerebro-cerebellar WM connections. Diffusion tensor tractography was used to characterise afferent and efferent cerebro-cerebellar tract integrity. False discovery rate corrections were applied in post-hoc comparisons. RESULTS BD patients exhibited higher fractional anisotropy (FA) in fronto-ponto-cerebellar tracts bilaterally compared to HC. Subphenotype-specific FA profiles were identified within the BD cohort. Regarding PP subgroups, we found FA changes in a) left contralateral fronto-ponto-cerebellar tract (depressive-PP > HC) and b) contralateral/ipsilateral fronto-ponto-cerebellar tracts bilaterally (manic-PP > HC). Regarding OP subgroups, we observed FA changes in a) left/right contralateral fronto-ponto-cerebellar tracts (depressive-OP>HC) and b) all fronto-ponto-cerebellar, most parieto-ponto-cerebellar and right contralateral occipito-ponto-cerebellar tracts (manic-OP>HC). In general, greater and more widespread cerebro-cerebellar changes were observed in manic-OP patients than in depressive-OP patients compared to HC. Manic-OP showed higher FA compared to depressive-OP patients in several afferent WM tracts. No GM differences were identified between BD and HC and across BD subgroups. CONCLUSIONS Our findings highlight fronto-ponto-cerebellar connectivity alterations in euthymic BD. Polarity-related subphenotypes have distinctive cerebro-cerebellar WM signatures with potential clinical and pathobiological implications.
Brain Structure and Function, 2019
Τhe middle longitudinal fasciculus (MdLF) was initially identified in humans as a discrete subcor... more Τhe middle longitudinal fasciculus (MdLF) was initially identified in humans as a discrete subcortical pathway connecting the superior temporal gyrus (STG) to the angular gyrus (AG). Further anatomo-imaging studies, however, proposed more sophisticated but conflicting connectivity patterns and have created a vague perception on its functional anatomy. Our aim was, therefore, to investigate the ambiguous structural architecture of this tract through focused cadaveric dissections augmented by a tailored DTI protocol in healthy participants from the Human Connectome dataset. Three segments and connectivity patterns were consistently recorded: the MdLF-I, connecting the dorsolateral Temporal Pole (TP) and STG to the Superior Parietal Lobule/Precuneus, through the Heschl’s gyrus; the MdLF-II, connecting the dorsolateral TP and the STG with the Parieto-occipital area through the posterior transverse gyri and the MdLF-III connecting the most anterior part of the TP to the posterior border of the occipital lobe through the AG. The lack of an established termination pattern to the AG and the fact that no significant leftward asymmetry is disclosed tend to shift the paradigm away from language function. Conversely, the theory of “where” and “what” auditory pathways, the essential relationship of the MdLF with the auditory cortex and the functional role of the cortical areas implicated in its connectivity tend to shift the paradigm towards auditory function. Allegedly, the MdLF-I and MdLF-II segments could underpin the perception of auditory representations; whereas, the MdLF-III could potentially subserve the integration of auditory and visual information.
Medical Radiology
During the Summer Olympics in 2004 the most frequent musculoskeletal injuries consisted of muscle... more During the Summer Olympics in 2004 the most frequent musculoskeletal injuries consisted of muscle strains, mainly of biceps femoris, gastrocnemius, adductors and rectus femoris, stress fractures (located mainly in the tibia, navicular bone and metatarsals) and knee injuries including isolated meniscal tears, ACL ruptures followed by more complex ligamentous injuries. Subtle muscle strains could be depicted by ultrasound whereas MRI
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 1991
Atherosclerosis, 1999
Poster session: Lipid lowering drugs negatively correlated with reaching target in MR. In HR inde... more Poster session: Lipid lowering drugs negatively correlated with reaching target in MR. In HR independent factors were baseline TG and LDL-c, diabetes and age; finally in CAD, only baseline LDL-c remained predictive of lipid control. Conclusions: I) In primary prevention, other risk factors as smoking, diabetes, hypertension and age, beside baseline lipid values may influence the efficacy of atorvastatin in reaching target in MD 2) In secondary prevention, baseline LDL-c remains the only predictive variable in MD control.
American Journal of Roentgenology, 2002
The purpose of this article is to present serial clinical and imaging findings for the &a... more The purpose of this article is to present serial clinical and imaging findings for the "absent" pulmonary artery. Data from six patients with this condition (five unilateral cases and one bilateral case) provide evidence concerning its embryology and illustrate the therapeutic implications of surgical intervention. In our series, we found the anatomy of the absent pulmonary artery to be consistent with a distal ductal origin and involution of the proximal sixth aortic arch. The absent pulmonary artery is a distinct embryologic entity that requires early detection and detailed investigation. Early surgical intervention may be justified in selected patients.
Journal of Magnetic Resonance Imaging, 1996
This prospective study evaluates the ability of MRI ushg T1-weighted fat-suppressed spin-echo (TI... more This prospective study evaluates the ability of MRI ushg T1-weighted fat-suppressed spin-echo (TI=) and dynamic gadolinium chelate (Gd) enhanced spoiled-gradient echo (WE) to detect the presence of pancreatic tumor in patients in whom spiral CT findings are inconclusive. Sixteen consecutive patients who underwent spiral CT and had findings that were considered inconclusive for pancreatic tumor underwent MR within 2 weeks of CT. Spiral CT and MR images were interpreted in a prospective fashion by separate individual investigators blinded to the results of the other imaging modality. CT was performed on a spiral CT scanner. MRI was performed on a 1.5-T MR machine. Imaging sequences included TlFS pre-Gd and post-Gd and SGE pre-Gd and immediately post-Gd. Data were analyzed using receiver operating characteristic (ROC) analysis. Confirmation was obtained by pancreatic biopsy (n = 4), surgical resection (n = l), and clinical imaging (n = 4) or clinical follow-up (n = 7). MRI was superior to spiral CT (P = .027) in this selected patient group at detecting or excluding pancreatic tumor by ROC analysis, with areas under the curve of .98Z and .764, respectively, which was significant (P = .041). The greatest advantage of MRI was i n patients in whom spiral CT demonstrated enlargement of the pancreatic head without clear definition of tumor, which was significant (P = .033). In 10 patients with this CT appearance, MRI demonstrated a high confidence for presence of tumor in four and a high c o ddence of absence in six. Association of imaging findings with patient diagnosis was significant for MRI (P = .001) but not significant for CT (P = .148). The results of our study suggest that MRI may add significant diagnostic information in patients in whom spiral CT is inconclusive for the presence of pancreatic tumor. The greatest advantage of MRI was in the evaluation of patients in whom spiral CT findings revealed an indeterminate enlarged pancreatic head.
Copyright © 2013 Argyro Mazioti et al. This is an open access article distributed under the Creat... more Copyright © 2013 Argyro Mazioti et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accor-dance of the Creative Commons Attribution License all Copyrights © 2013 are reserved for SCIRP and the owner of the intellectual property Argyro Mazioti et al. All Copyright © 2013 are guarded by law and by SCIRP as a guardian. Objective: In the embryonic period, several developmental anomalies of the posterior cerebral circulation might occur. Digital subtractive angiography used to be the imaging technique of choice for the illustration of such variations. Nowadays, the development of MR imaging has led to a new entry in the diagnostic archer’s quivery, the MR an-giography, with which most of these variations may be diagnosed. Purpose of this study is to illustrate these anatomic variants, their incidence and their potenti...
Purpose. We studied the prognostic significance of Magnetic Resonance Spectroscopy (MRS) in opera... more Purpose. We studied the prognostic significance of Magnetic Resonance Spectroscopy (MRS) in operated high grade gliomas. Materials and Methods. Twelve patients were treated with radiotherapy and Temozolomide. The MRS data were taken four weeks after operation (before radiotherapy) and every six months after the completion of RT. The N-acetyl aspartate, choline, creatine, and myo-inositol parameters were quantified, analyzed, and correlated to recurrence-free survival (RFS). Results. The median RFS was 26.06 months. RFS was significantly worse in elderly patients (= 0.001) along with the higher choline/creatine ratios at either baseline (= 0.003) or six months post Radiotherapy (= 0.042). Median RFS was 23 months in high choline/creatine levels ≥2 at 6 months after radiotherapy and 11 months for those with <2 choline/creatine levels. There was a significant correlation of maximum difference of choline/creatine ratio with RFS (rho = 0.64, = 0.045). Conclusion. Age and choline/creatine ratio are strong independent prognostic factors in high grade gliomas.
Diagnostics
To compare different parameters of the sphericity index of the ablation zone following microwave ... more To compare different parameters of the sphericity index of the ablation zone following microwave ablation (MWA) on cirrhotic- and healthy-liver parenchyma in a series of patients treated with the same MWA system. Institutional database research identified 46 patients (77 lesions) who underwent MWA. “Cirrhotic liver group” (CLG) included 35 hepatocellular carcinoma lesions; “healthy liver group” (HLG) included 42 metastatic lesions. The long axis (LAD), short axis 1 (SAD-1) and 2 (SAD-2), the mean SAD-1 and SAD-2 (mSAD) diameter (in mm) and the mean sphericity (mSPH) index of the ablation zones were evaluated for each treated lesion in both groups from baseline to follow-up. A mixed model analysis of variance reported significant main effect of group on SAD-1 (p = 0.023), SAD-2 (p = 0.010) and mSAD (p = 0.010), with HLG showing lower values compared to CLG. No differences were detected on the LAD (pFDR = 0.089; d = 0.45), and mSPH (pFDR = 0.148, d = 0.40) between the two groups. Howe...
Diagnostics, 2021
To compare different parameters of the sphericity index of the ablation zone following microwave ... more To compare different parameters of the sphericity index of the ablation zone following microwave ablation (MWA) on cirrhotic- and healthy-liver parenchyma in a series of patients treated with the same MWA system. Institutional database research identified 46 patients (77 lesions) who underwent MWA. “Cirrhotic liver group” (CLG) included 35 hepatocellular carcinoma lesions; “healthy liver group” (HLG) included 42 metastatic lesions. The long axis (LAD), short axis 1 (SAD-1) and 2 (SAD-2), the mean SAD-1 and SAD-2 (mSAD) diameter (in mm) and the mean sphericity (mSPH) index of the ablation zones were evaluated for each treated lesion in both groups from baseline to follow-up. A mixed model analysis of variance reported significant main effect of group on SAD-1 (p = 0.023), SAD-2 (p = 0.010) and mSAD (p = 0.010), with HLG showing lower values compared to CLG. No differences were detected on the LAD (pFDR = 0.089; d = 0.45), and mSPH (pFDR = 0.148, d = 0.40) between the two groups. Howe...
The most common paediatric malignancies in the head and neck area consisted of lymphoma, leukaemi... more The most common paediatric malignancies in the head and neck area consisted of lymphoma, leukaemia, brain tumours, neuroblastoma, Wilms’ tumour, sarcomas and primary rhabdomyosarcomas. This review reports in brief radiological diagnosis and staging together with radiation treatment, in terms of common clinical practice. Ultrasound, computerized tomography, magnetic resonance imaging and lately positron emission tomography are playing an important diagnostic role, which is discussed. Further, the radiation treatment represents an important weapon against paediatric neoplasia. In general, the prescribed dose is 35 (1.7 Gy per fraction), 24 (1.6 Gy per fraction) and 54–60 Gy (1.8 Gy per fraction) for lymphoma, leukaemia and central nervous system tumours, respectively. Modern techniques such as intensity modulated radiation therapy and protons, offer tremendous scope, although these are not widely used yet. The main aspect related to irradiation in paediatric tumours in the head and ne...
Asian Pacific journal of cancer prevention : APJCP, 2016
BACKGROUND The aim of this study was to investigate whether electrochemotherapy is a clinically a... more BACKGROUND The aim of this study was to investigate whether electrochemotherapy is a clinically and cost-effective treatment option against skin tumors. MATERIALS AND METHODS We performed an analysis of the current literature based on database searches in PubMed/MEDLINE and we included articles till July 2012. Terms used for the search were 'electrochemotherapy', 'skin cancer', 'recurrence', and 'cutaneous and subcutaneous tumors'. Only papers published in English were included. In addition, we performed an analysis of the cost effectiveness of the method. RESULTS The combination of physics and chemistry is the foundation for electrochemotherapy and its efficacy, independent of the tumor histology. Clinical data showed that ECT is well tolerated and can be used in difficult cases without other available treatment options. The analysis also showed that the treatment is feasible and cost-effective. CONCLUSIONS Electrochemotherapy is a clinically efficie...
Purpose: To assess the prevalence and the qualitative and quantitative characteristics of left ve... more Purpose: To assess the prevalence and the qualitative and quantitative characteristics of left ventricular (LV) trabeculation in patients with non-ischaemic primary or secondary cardiomyopathies using detailed cardiac magnetic resonance imaging (MRI) analysis and to ascertain whether left ventricular trabeculations are related to global systolic LV function in different cardiomyopathies. Material and Methods: One hundred and twenty four patients were studied using cardiac MRI, 10 with isolated left ventricular non-compaction (ILVNC), 24 with dilated cardiomyopathy (DCM), 27 with hypertrophic cardiomyopathy (HCM), 22 with cardiac sarcoidosis and 20 with arrhythmogenic right ventricular cardiomyopathy (ARVC). Twenty one patients with acute onset of myocarditis and no prior or familial history of cardiac disease served as controls. Results: Myocardial trabeculations were frequent in cardiomyopathies and were significantly greater in ILVNC and more frequent and extensive at apical seg...
Annals of Gastroenterology : Quarterly Publication of the Hellenic Society of Gastroenterology, 2013
We strongly recommend to the readers of Annals of Gastroenterology two interesting studies by Shi... more We strongly recommend to the readers of Annals of Gastroenterology two interesting studies by Shiina et al [1] and Kim et al [2] on the outcome of radiofrequency ablation and the prognostic factors which seem to govern it for the treatment of hepatocellular carcinoma (HCC). HCC is the third leading cause of cancer-related death and the fifth - sixth most common cancer [1-3]. Transplantation and surgical resection are the therapies of choice for HCC [4,5]. However, shortage of organ donors restricts liver transplantation, whilst only one fifth of HCC patients are candidates for surgical resection [1,2]. For different reasons (patient refusal, impaired liver function, co-morbidities) surgical resection cannot be considered an option for the majority of HCC patients. In this group of patients, percutaneous ablation therapies act as attractive alternatives with similar success and survival rates and significantly lower post-therapeutic pain and other complications. Furthermore, percutan...
The British journal of radiology, 2021
OBJECTIVES To retrospectively evaluate feasibility and safety of CT-guided percutaneous radiofreq... more OBJECTIVES To retrospectively evaluate feasibility and safety of CT-guided percutaneous radiofrequency ablation (RFA) of metastatic lymph nodes (LN) in terms of achieving local tumor control. METHODS Institutional database research identified 16 patients with 24 metastatic LNs who underwent percutaneous CT-guided radiofrequency ablation. Mean patient age was 66.6 ± 15.70 years (range 40-87) and male/female ratio was 8/8. Contrast-enhanced CT or MRI was used for post-ablation follow-up. Patient and tumor characteristics and RFA technique were evaluated. Technical and clinical success on per tumor and per patient basis as well as complication rates were recorded. RESULTS Mean size of the treated nodes was 1.78 ± 0.83 cm. The mean number of tumors per patient was 1.5 ± 0.63. The mean procedure time was 56.29 ± 24.27 min including local anesthesia, electrode(s) placement, ablation and post-procedural CT evaluation. Median length of hospital stay was 1.13 ± 0.34 days. On a per lesion bas...
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Papers by Nikolaos Kelekis