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Biomedical subjects

L Vlahos

Publications and source records attributed to L Vlahos.

At least 37 records · Page 2Linked to original sources
PubMed2001

The diagnostic X-ray protection characteristics of Panelcrete, Aquapanel, Betopan and Gypsoplak Superboard.

Panelcrete, Aquapanel and Betopan are cement-based building materials with uses similar to those of gypsum wallboard, whose properties as a diagnostic X-ray shielding material have been extensively studied. The X-ray attenuation characteristics of these cement-based boards as well as those of a gypsum wallboard, Gypsoplak Superboard, are investigated for broad beam geometry conditions and for tube potentials of 50 kVp, 70 kVp, 100 kVp, 125 kVp and 140 kVp. Comparisons between these materials as well as with published data for gypsum wallboard are made. An example of their use as secondary barriers is given. Furthermore, it is confirmed that when building materials are considered for diagnostic X-ray shielding, calculations based on data for similar materials and corrected for density differences can be used only as an approximation.

Construction Materials↗
PubMed2000

Comparison of dual spin echo echo planar imaging (SE_EPI), turbo spin echo with fat suppression and conventional dual spin echo sequences for T(2)-weighted MR imaging of focal liver lesions.

The performance of T(2)-weighted spin-echo version of echo planar imaging (SE_EPI), conventional spin echo (SE) and fat-suppressed turbo spin-echo (TSE_SPIR) sequences for the detection of focal liver lesions was evaluated. Twenty patients that were included in our study, had CT examinations prior to the MR study and were scheduled for surgery for removal of liver lesions. All patients had intraoperative sonographic examinations. Qualitative and quantitative analysis of the images was performed. Overall image quality of SE_EPI sequences was better than SE (p<0.001) and similar to TSE_SPIR sequences. There were fewer motion and ghost artifacts on SE_EPI and TSE_SPIR images compared to SE images (p<0.001). Susceptibility artifacts were statistically equivalent on SE_EPI and SE images (p<0.001) while chemical shift artifacts were equally observed on SE and SE_EPI sequences. Overall image quality of EPI-SE and TSE_SPIR sequences was better compared to SE sequences. There was no significant difference in the number of lesions detected by each of the three sequences. Quantitative analysis showed that liver/lesion contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of liver, lesion, spleen was higher on TSE_SPIR sequences (p<0.001) while SE_EPI and SE sequences showed non-significant differences (p>0.05). SE_EPI sequences of the liver resulted in fewer artifacts and shorter acquisition times than SE sequences. They provide a diagnostic performance similar to TSE_SPIR and better than that of SE sequences.

Adult↗
PubMed2000

Psychophysiological evaluation of short-term neurotoxicity after prophylactic brain irradiation in patients with small cell lung cancer: a study of event related potentials.

BACKGROUND: The aim of this study was to show, whether a certain prophylacting applicable radiation affects the cognition, particularly, the specific cognitive components P50, N100, P300 and N400 of auditory event related potentials (ERPs) during a short memory test. METHODS AND MATERIALS: Eleven patients with small cell lung cancer (SCLC), who had presented complete response of disease after chemotherapy and radical radiotherapy in the lung, were prescribed to receive a prophylacting cranial irradiation (PCI) with a 6 MeV linear accelerator. The dose schedule was consisting of a total dose up to 30 Gy in 10 fractions, within 12 days (5 days a week). The psychophysiological approach before and after PCI was assessed by measurements of the auditory ERPs during a short memory performance using the digit-span Wechsler test. Components of ERP were recorded from 15 scalp electrodes. Additionally, symptomatology of depression and anxiety were assessed using Zung Self-Rating Depression Scale and Spielberger Anxiety Inventory, respectively, for pre- and post-PCI. RESULTS: No significant difference was noticed pre- and post-radiotherapy of all particular level of psychophysiological analysis concerning both the latencies and the amplitudes of ERPs auditory components P50, N100, P300 and N400 (P > 0.05, Wilcoxon signed test). Additionally, no changes were found with regard to behavioral performance (memory recall), depression symptomatology and state anxiety, according to pre- and post-radiation measurements. However, the self-reported depression symptomatology showed that the patients presented moderate depression. CONCLUSION: No short-term psychophysiological neurotoxicity was detected with this PCI schedule using these instruments, lending additional support to evidence suggesting the benefit of this certain PCI schedule for patients with SCLC.

Aged↗
PubMed2000

Role of the new imaging modalities in the investigation of Meniere's disease.

The incidence of nonvisualization of the vestibular aqueduct and the endolymphatic duct-endolymphatic sac (ED-ES) complex as well as the type of periaqueductal pneumatization were evaluated in 23 patients with definite Meniere's disease (MD) by high-resolution CT and by MRI. Fifty subjects with no previous history of any ear disease were used as a control group. High-resolution CT results disclosed that in the control group the percentage of nonvisualized vestibular aqueduct (3.4%) was statistically significantly lower than in the MD group, when either the diseased ear (27.8%) or the nondiseased ear of the same group (22.2%) was examined. In addition, no differences were observed between the diseased and nondiseased ears of the patients with MD. The periaqueductal pneumatization was also found to be statistically significantly lower in the MD group. As regards the MRI examination, the results of the analysis showed that the ED-ES complex was visualized more frequently in the ears of the control subjects (64.1%) than in the diseased ears of the patients with Meniere's disease (39.1%). This difference had a marginal statistical significance (P approximately 0.05). We discussed the results in relation to possible underlying pathophysiologic mechanisms involving the flow of endolymph toward the ES during the different stages of the disease.

Adult↗
PubMed2000

Cystic pancreatic neoplasms: computed tomography and magnetic resonance imaging findings.

Cystic pancreatic neoplasms include serous cystadenomas (SCA), mucin-producing cystic tumors, cystic islet-cell tumors, and cystic solid and papillary epithelial neoplasms. Imaging techniques are of great value in the demonstration and differential diagnosis of these tumors. In this article we present the computed tomography (CT) and magnetic resonance imaging (MRI) findings of the aforementioned cystic neoplasms. Although the radiological features are in many cases informative, a significant overlap does exist; fine-needle aspiration biopsy and cytology or excisional biopsy and histological examination are necessary to determine a definitive diagnosis.

Adenoma, Islet Cell↗
PubMed1999

MR appearance of pelvic hemangiopericytoma.

A case of pelvic hemangiopericytoma in a 59-year-old woman is reported. The MR imaging features are presented. The tumor was unresectable and the patient received postoperative irradiation of 4200 cGy on the pelvis. One year after diagnosis, metastasis to a lumbar vertebra was discovered and additional irradiation of 3900 cGy was applied. One year later, CT showed control of the pelvic tumor and its metastasis.

Biopsy↗
PubMed1999

Endovaginal color Doppler sonographic evaluation of ectopic pregnancy in women after in vitro fertilization and embryo transfer.

The aim of this study was to evaluate the value of endovaginal color Doppler ultrasonography in the early diagnosis of ectopic pregnancy in women after in vitro fertilization and embryo transfer, and to correlate the sonographic findings with ss-hCG serum levels. Thirty-five patients had proven ectopic pregnancies and 4 other patients had heterotopic pregnancies. The diagnosis was disclosed correctly in all cases by endovaginal color Doppler US by identifying an adnexal mass with placental flow and a nongravid uterus called a "cold uterus". An intrauterine sac with "double ring sign" was found in all normal intrauterine pregnancies when the hCG levels exceeded 1000 IU/l but in none of the patients with ectopic pregnancy (EP). These findings suggest the efficacy of the discriminatory hCG serum level of 1000 IU/l in the investigation of EP. In conclusion, this study describes the diagnostic importance of transvaginal color Doppler US in correlation with hCG serum levels in the early detection of EP avoiding life-threatening complications and improving patient outcome.

Adult↗
PubMed1999

Abdominal retained surgical sponges: CT appearance.

Retention of surgical sponges is rare. They cause either an aseptic reaction without significant symptoms or an exudative reaction which results in early but nonspecific symptoms. Computed tomography is very useful for recognition of retained sponges. The appearance of retained sponges is widely variable. Air trapping into a surgical sponge results in the spongiform pattern which is characteristic but unfortunately uncommon. A low-density, high-density, or complex mass is found in the majority of cases, but these patterns are not specific. Sometimes, a thin high-density capsule may be seen. Rim or internal calcification is a rare finding. Finally, a radiopaque marker is not a reliable sign. Differentiation from abscess and hematoma is sometimes difficult.

Abdomen↗
PubMed1999

MR imaging of complex tail-gut cysts.

Retrorectal-cyst hamartomas (RCH) are rare developmental tail-gut cystic tumours of the retrorectal space, which occasionally undergo malignant transformation. We describe the magnetic resonance imaging (MRI) findings in two patients with RCH and in a third patient with unclassified sarcoma arising from a RCH. The RCH were hypointense or hyperintense on T1-weighted images and hyperintense on T2-weighted images; they did not enhance and they contained multiple septations. A solid component in the periphery of one cyst was markedly hypointense on T2-weighted images in keeping with fibrous material. The sarcoma arising from the wall of the RCH enhanced and was of intermediate signal intensity on all sequences. MR may help establish the diagnosis of RCH if an unenhanced cystic tumour is discovered in the retrorectal space and it can help detect those rare cases of malignant transformation of these developmental tumours.

Adult↗
PubMed1999

Selective arterial embolization in the management of symptomatic renal angiomyolipomas.

Current management of renal angiomyolipomas (AMLs) include observation, transcatheter embolization and partial or total nephrectomy. Patients symptoms and size of the lesion are the determinants for the choice of the treatment. In general symptomatic or greater than 8 cm masses require intervention. A retrospective study of five patients presented with symptomatic lesions and treated with selective transcatheter embolization, over a 3 year period was performed in our hospital. A total of eight embolizations were performed, all on an emergency basis due to retroperitoneal bleeding or significant hematuria. Surgical intervention was necessary in one case, due to massive rebleeding on the fourth post-procedural day. Two patients rebled within 6 months and 2 years respectively, and were managed successfully with additional embolization. The remaining two patients are still asymptomatic 26 and 18 months after the successful initial result. Experience with this procedure is reported on with emphasis to the clinical outcome. It is believed that selective arterial embolization should be the standard initial therapy for symptomatic renal AMLs.

Adolescent↗
PubMed1999

Continuous subcutaneous administration of high-dose salmon calcitonin in bone metastasis: pain control and beta-endorphin plasma levels.

This prospective nonrandomized trial was performed to evaluate the efficacy of salmon calcitonin (sCT) in controlling pain related to bone metastasis in cancer patients and the relation of sCT's analgesic efficacy with beta-endorphin blood levels. The study group consisted of 22 cancer patients with bone metastases (male 13 and female 9, age range 38-77 years). Pain control was first achieved by continuous subcutaneous (s.c.) morphine administration. The next increase in pain was managed with continuous s.c. administration of 400 IU/day sCT. Beta-endorphin blood levels were measured before and during sCT administration. The first measurement was taken before sCT administration; subsequent measurement occurred at 12, 24, and 48 hours and 7 days after the commencement of treatment. Pain scores were monitored by a visual analogue scale. A complete blood count and a biochemical screening profile were taken before the administration of calcitonin and also on the seventh and the fifteenth day of the administration. The results showed a satisfactory analgesic effect. The mean pain score before the calcitonin administration was 4.43 and the score on the seventh day was 1.17. The gradual reduction of pain score was associated with an increase in beta-endorphin blood levels (increase to 147.2% of baseline on the seventh treatment day). In three cases, no satisfactory analgesic effect was obtained and pain control was achieved by increasing the continuous s.c. morphine dosage. No significant side effects were observed. These data suggest that sCT in high doses may be a useful adjuvant analgesic when combined with low doses of morphine in continuous s.c. administration for the management of metastatic bone pain.

Adult↗
PubMed1999

Arteriovenous shunting in a giant renal angiomyolipoma. A rare condition.

We report a case of a 33-year-old woman with tuberous sclerosis and bilateral angiomyolipomas. She suffered from acute left flank pain due to retroperitoneal haemorrhage. During renal arteriography an arteriovenous shunting was found in the left tumour. Angiomyolipoma is a rare cause of angiographically demonstrable arteriovenous shunting.

Adult↗
PubMed1999

Optimizing hospital-based home care for dying cancer patients: a population-based study.

Health-related quality of life (HRQL) is difficult to define and measure. It is a generic term that includes concepts such as physical health, life satisfaction, psychological well-being and self-integrity. Realizing and appreciating the importance of HRQL is crucial for physicians if they are to be in a position to offer appropriate suggestions in assisting patients and their families in the decision-making process regarding cancer treatment and terminal care. In order to determine whether Greek physicians take into consideration HRQL when assessing different therapeutic options, we conducted a postal survey. A total of 1500 Greek physicians (internists, oncologists and anaesthesiologists) were asked to complete a questionnaire. We received replies from 1280 (85%). In summary, we found that Greek physicians: (1) have already started taking HRQL into consideration when reviewing their therapeutic options; (2) increasingly include HRQL in research studies as an outcome measure; (3) do not yet have thoroughly sufficient training in the holistic care of cancer patients and their families; (4) mostly do not have the opportunity to work in interdisciplinary therapeutic teams where they can exchange ideas and consider different aspects of alternative therapeutic methods. It is concluded that HRQL has already been introduced as an important determinant of therapeutic choices in cancer care in Greece. However, efforts need to be made to allow HRQL to enjoy its appropriate place in cancer care.

Adult↗
PubMed1999

Patient doses from barium meal and barium enema examinations and potential for reduction through proper set-up of equipment.

Patient doses for barium meal and barium enema examinations, performed at two Greek hospitals, were measured using a dose-area product meter. The results were analysed to obtain the contributions of fluoroscopy and radiography to the dose as well as a number of other dose related parameters for each examination. The doses observed are within the range of values reported by other authors and comply with the dose reference levels (DRLs), proposed from relevant surveys in the UK and The Netherlands. However, comparison between the two hospitals revealed significant differences in the contributions to dose from the various parts of the examinations. To determine the reasons for these differences, measurements of dose related parameters were made using a Plexiglas phantom and standard clinical X-ray machine settings. Factors contributing to increased dose delivery were determined and recommendations have been made concerning ways in which doses might be reduced in each hospital, without degradation of the diagnostic quality of these examinations.

Barium Sulfate↗
PubMed1999

Imaging findings in primary carcinoid tumour of the liver with gastrin production.

We present a 57-year-old man with Zollinger-Ellison syndrome who had undergone total gastrectomy 12 years previously. At that time, a cystic mass in the left lobe of the liver was palpated but was not removed. The patient currently had high serum gastrin levels. Abdominal ultrasound, CT and MR images showed a well defined liver mass with solid and cystic components. The lesion was resected and a primary hepatic carcinoid tumour was diagnosed. Post-operatively, serum gastrin levels were normal. A primary liver carcinoid may appear as multicystic liver mass with solid components. Careful exclusion of a primary tumour elsewhere is required to establish the diagnosis of this rare entity.

Carcinoid Tumor↗
PubMed1999

Bone lesions with soft-tissue mass: magnetic resonance imaging diagnosis of lymphomatous involvement of the bone marrow versus multiple myeloma and bone metastases.

Bone metastases from solid primary tumors, as well as multiple myeloma and secondary lymphoma may all present with bone lesions and associated soft-tissue masses on magnetic resonance images of the spine. In bone metastases and myeloma, the cortex of the affected bone is usually destroyed and a bulging contour is observed at the site of extraosseous spread. In cases of lymphomatous involvement of the bone marrow, however, we have observed that spread to the extraosseous soft-tissues occurs without alteration of the shape or contour of the affected bone. In order to assess whether this pattern of spread is indeed suggestive or even diagnostic of lymphoma of the bone marrow, we reviewed spinal bone marrow MR images of 66 patients, with bone metastases from solid primary tumors (33 patients), multiple myeloma (20 patients) and stage IV lymphoma with bone marrow involvement (13 patients), who had bone lesions and contiguous soft-tissue masses. If tumor was present on either side of the bony cortex but the contour of the affected bone was preserved, a "wrap-around" sign was diagnosed. A "wrap-around" sign was found in 12 of the 13 patients with lymphoma but in none of the patients with metastases or myeloma. On MR images of the bone marrow, the demonstration of tumor spread beyond the bony cortex without disruption of the outline of the diseased bone may favor the diagnosis of lymphoma more than that of metastases or multiple myeloma.

Adolescent↗