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Nikolaos L Kelekis

Publications and source records attributed to Nikolaos L Kelekis.

13 recordsLinked to original sources
PubMed2006

Iron chelation treatment with combined therapy with deferiprone and deferioxamine: a 12-month trial.

The simultaneous use of deferioxamine (DFO) and deferiprone (DFP) has an additive effect in iron excretion in transfusion-dependent thalassemic patients. In a prospective study, we evaluated the safety and effectiveness of combined therapy with these two chelators. Fifty patients with beta-thalassemia were uniformly treated with DFP for 4 days per week and combined therapy with DFP and DFO for 3 days of the week. Efficacy was evaluated by ferritin and cardiac shortening fraction (SF). Hepatic hemosiderosis was also assessed by estimation of the T2 relaxation time by magnetic resonance in a subgroup of patients. Forty-three patients completed 1 year of therapy. Mean ferritin decreased from 3363.7 +/- 2144.5 microg/L to 2323.2 +/- 1740.8 microg/L (P < 0.0001). The reduction was significant even in the group of patients with ferritin <2500 microg/L. Significant improvement in T2 relaxation and SF was observed. The most common adverse events were gastrointestinal symptoms (20%) and transaminasemia (18%). The rate of agranulocytosis was 4.2 cases per 100 patient-years. Prolonged use of combined therapy with DFP and DFO is effective in decreasing iron load and improving cardiac function. Its possible association with higher incidence of agranulocytosis emphasizes the need for close monitoring.

Adolescent↗
PubMed2006

R2 relaxometry with MRI for the quantification of tissue iron overload in beta-thalassemic patients.

PURPOSE: To evaluate the usefulness of a time-efficient MRI method for the quantitative determination of tissue iron in the liver and heart of beta-thalassemic patients using spin-spin relaxation rate, R2, measurements. MATERIALS AND METHODS: Images were obtained at 1.5 T from aqueous Gd-DTPA solutions (0.106-8 mM) and from the liver and heart of 46 beta-thalassemic patients and 10 controls. The imaging sequence used was a respiratory-triggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spin-echo (SE) pulse sequence (TR = 2000 msec, TE(min) = 5 msec, echo spacing (ES) = 5 msec, matrix = 192 x 256, slice thickness = 10 mm). Liver iron concentration (LIC) measurements were obtained for 22 patients through biopsy specimens excised from the relevant liver segment. Biopsy specimens were also evaluated regarding iron grade and fibrosis. Serum ferritin (SF) measurements were obtained in all patients. RESULTS: A statistically significant difference was found between patients and healthy controls in mean liver (P < 0.004) and myocardium (P < 0.004) R2 values. The R2 values correlated well with Gd DTPA concentration (r = 0.996, P < 0.0001) and LIC (r = 0.874, P < 0.0001). A less significant relationship (r = 0.791, P < 0.0001) was found between LIC measurements and SF levels. R2 measurements appear to be significantly affected (P = 0.04) by different degrees of hepatic fibrosis. The patients' liver R2 values did not correlate with myocardial R2 values (r = 0.038, P < 0.21). CONCLUSION: Tissue iron deposition in beta-thalassemic patients may be adequately quantified using R2 measurements obtained with a 16-echo MRI sequence with short ES (5 msec), even in patients with a relatively increased iron burden.

Adolescent↗
PubMed2006

Patient radiation exposure measurements during interventional procedures: a prospective study.

This is a prospective study with the purpose of assessing patient radiation dose and stochastic risk (risk for fatal cancer) in a patient population undergoing interventional radiological (IR) procedures. Measurements were performed on 36 consecutive patients undergoing percutaneous transluminal angioplasty (PTA, n=18), transjugular intrahepatic portosystemic shunt (TIPS, n=3), diagnostic angiography (DA, n=6), arterial embolization (AE, n=3), and hepatic neoplasm chemoembolization (HCE, n=6). Kerma area product (KAP) was used as a measure of x-ray exposure to the patient. Mean KAP value per procedure was 79+/-50 Gy cm for PTA, 139+/-55 Gy cm for TIPS, 110+/-44 Gy cm for DA, 325+/-145 Gy cm for AE, and 150+/-76 Gy cm for HCE. Forty-six percent of total KAP value was attributed to fluoroscopy. In conclusion, we showed that a linear correlation between effective dose and KAP was found (r=0.84), which could be used for estimating patient effective dose using KAP measurements. Small changes to the number of digital frames acquired result in substantial change of the total KAP in interventional radiological procedures. Stochastic risk from IR procedures is quite low for the patient. Measuring KAP is a simple and accurate method, which provides the interventional radiologist with a good estimation of the patient's relative risk for stochastic effects.

Aged↗
PubMed2005

Minimally invasive techniques in orthopedic oncology: radiofrequency and laser thermal ablation.

Image-guided percutaneous thermal ablation is a safe and effective method to reduce pain in patients with painful bone tumors. Computed tomography-guided radiofrequency or laser ablation is the modality of choice for most osteoid osteomas. Radiofrequency or laser thermal ablation also offers an alternative method for palliation of localized, painful osteolytic metastatic lesions. Pain can be reduced and neural damage prevented, improving the quality of life for patients with cancer who often have multimorbid conditions and limited life expectancy. A multidisciplinary approach that includes orthopedic surgeons, neurosurgeons, medical and radiation oncologists, and interventional radiologists is essential to manage these patients.

Bone Neoplasms↗
PubMed2003

Giant adrenal myelolipoma with minimal fat content in a patient with homozygous beta-thalassemia: appearance on MRI.

Giant adrenal myelolipoma is an uncommon entity. We present the atypical MR imaging findings of a giant adrenal myelolipoma in a patient with homozygous beta-thalassemia with histopathology correlation. The tumor showed a drop in signal on the opposed-phase images, with no evidence of macroscopic fat contents, and demonstrated very high signal intensity on T2-weighted images. Giant adrenal myelolipoma should be considered in the differential diagnosis of tumors with the combination of the above MR imaging characteristics.

Adipose Tissue↗
PubMed2002

"Absent" pulmonary artery in one adult and five pediatric patients: imaging, embryology, and therapeutic implications.

OBJECTIVE: 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. CONCLUSION: 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.

Adult↗
PubMedDate not supplied

Confluent hepatic fibrosis as the presenting imaging sign in nonadvanced alcoholic cirrhosis.

Confluent hepatic fibrosis (CHF) is usually a feature of advanced cirrhosis, while occurrence in early stage compensated cirrhosis is uncommon. We report the imaging findings of masslike CHF in a patient with previously unsuspected compensated alcoholic cirrhosis. The combination of partially wedge shape, minimal capsular retraction, and homogeneous delayed enhancement on multiphase contrast-enhanced spiral CT led to the characterization of the lesions and establishment of the diagnosis of cirrhosis.

Contrast Media↗
PubMedDate not supplied

Evaluation of spiral computed tomography versus ventilation/perfusion scanning in patients clinically suspected of pulmonary embolism.

OBJECTIVE: To prospectively evaluate the diagnostic accuracy of spiral computed tomography (CT) versus ventilation/perfusion (V/Q) scanning in the examination of patients clinically suspected of having pulmonary embolism (PE). PATIENTS AND METHODS: Sixty-three patients, presenting to the emergency department and departments of radiology and nuclear medicine of a large hospital, highly suspected of having PE, underwent sequential imaging testing with V/Q scanning and contrast-enhanced spiral CT, in addition to other clinical and laboratory tests. RESULTS: PE was diagnosed in 42 (66.7%) of the 63 patients. Thirty-nine of these 42 patients had positive findings in their CT scans, while 18 of the remaining 21 patients without PE had negative findings in their spiral CT [sensitivity, 92.9%, specificity, 85.7% Positive Predictive Value (PPV), 92.9%, Negative Predictive Value (NPV), 85.7%]. V/Q scans showed high-probability of PE in 24 of the 42 patients with PE and were negative in 9 of the remaining 21 patients without PE (sensitivity, 571%, specificity, 42.9%, PPV, 66.7%, NPV, 33.3%). There were statistically significant differences in specificity and sensitivity favoring spiral CT among men and women patients or patients > 50 years old. Fifty-four patients (85.7%) rated their satisfaction towards spiral CT as 'good' or 'very good', whereas the respective rate for V/Q scanning was only 14.3%. CONCLUSION: Spiral CT has an excellent sensitivity, specificity, PPV and NPV for the diagnosis of PE and it could be used as the first-line imaging modality in patients suspected of PE.

Adolescent↗