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Biomedical subjects

L Vlahos

Publications and source records attributed to L Vlahos.

At least 73 records · Page 4Linked to original sources
PubMed1994

A comparative study between Gd-DTPA and oral magnetic particles (OMP) as gastrointestinal (GI) contrast agents for MRI of the abdomen.

In the present study we compared two gastrointestinal contrast agents--Gd-DTPA, a positive signal, and oral magnetic particles (OMP), a negative signal contrast agent--in patients who were referred for MR imaging of the abdomen. Altogether 60 patients were examined with the former and 28 patients with the latter contrast before and after the administration of contrast media. Gd-DTPA was given either per os or per rectum. In comparing the results, it was shown that the diagnostic accuracy of postcontrast MRI in both groups was more or less similar to CT but much higher as compared with plain MRI. In the OMP series, first the contrast between the GI-filled lumen and the surrounding fat was much superior to that of the Gd-DTPA and, second, there was no evidence of any artifacts from bowel motion. However, the overall accuracy of the Gd-DTPA group was better compared with that of the OMP group. This was due to underfilling of the distal bowel because the OMP in those patients was administered only per os. Finally, Gd-DTPA had a more pleasant taste and fewer side effects. It is concluded that both contrast media are suitable for the upper abdomen because the results are comparable, whereas for the lower abdomen Gd-DTPA is superior because it can be used from both routes.

Abdomen↗
PubMed1994

Localized mastoiditis simulating a facial nerve schwannoma on MRI.

A case of a single inflamed mastoid air cell is described. This was initially interpreted as a facial nerve schwannoma on MRI examination. Careful evaluation of the signal characteristics and additional findings from the high resolution CT examination helped to establish the correct diagnosis.

Adult↗
PubMed1994

Oral magnetic particles as a contrast agent for MR imaging of the abdomen. A phase III clinical trial.

Twenty patients were investigated with MR imaging of the abdomen before and after the administration of oral magnetic particles in the form of a per os solution for opacification of the gastrointestinal lumen. The parameters which were evaluated were a) distribution of the contrast medium in the gastrointestinal tract, b) delineation with the contrast medium of the region of interest c) image quality of general contract effect of the contrast medium d) diagnostic accuracy compared with CT and plain MRI of the same region. At a concentration of 0.5 mg/oral magnetic particles produced a constant negative signal from the gastro- intestinal tract in all spin echo sequences (T1 weighted, T2 weighted, proton density). Its diagnostic accuracy was similar to CT but better than plain MR examination of the same region in 70% of the cases. The diagnostic accuracy was inferior in the lower abdomen because of underdistension of the bowel. Perhaps the solution to the problem would be the combined per os and per rectum administration of the contrast medium.

Abdomen↗
PubMed1993

Retrocrural masses of extramedullary hemopoiesis in beta-thalassemia.

A case of extramedullary hemopoiesis in an 18-yr-old girl suffering from beta-thalassemia is reported. Extramedullary hemopoietic masses were localized apart from the paraspinal region in the retrocrural areas as well as the presacral region associated with massive destruction of the sacrum. The importance of recognition of hemopoietic masses in these regions in conditions other than hereditary hemolytic anaemias is briefly discussed.

Adolescent↗
PubMed1993

Pathological fracture in haemoglobinopathy: treatment by irradiation.

A patient suffering from thalassaemia, with extreme osteoporosis, coarse trabeculation and cortical thinning of the bones, developed a pathological fracture of the left hip. This was treated by a single dose of radiotherapy. It is suggested that the radiotherapy facilitated the healing process by eliminating the causative factor of the fracture, which was the expanding and over-proliferating bone marrow.

Adult↗
PubMed1992

Magnetic resonance angiography compared to intra-arterial digital subtraction angiography in patients with subarachnoid haemorrhage.

In order to evaluate the sensitivity and specificity of magnetic resonance angiography (MRA) in spontaneous subarachnoid haemorrhage, 14 patients with recent haemorrhage verified by CT or lumbar puncture were investigated with both selective intra-arterial digital subtraction angiography (IA-DSA) and MRA by two independent teams, each having the same preangiographic information. The results were compared with each other and whenever possible (all positive cases except one) with those of surgical intervention. Seven patients were identified by MRA and IA-DSA as having a single aneurysm on the circle of Willis, 1 an aneurysm of the posterior inferior cerebellar artery 1 an aneurysm of the internal carotid artery (siphon) and 2 patients with two aneurysms on the circle of Willis. MRA and IA-DSA both failed to demonstrate aneurysms in 2 cases. Three patients had negative results on both methods and no surgical intervention was attempted. The aneurysms ranged from 0.3 to 1.5 cm in size. In most cases there was agreement between MRA and DSA, leading us to believe that, if the proper protocols are followed, MRA is a powerful alternative to other established methods in the detection of intracranial aneurysms. At this stage it will not replace IA-DSA prior to surgery, but the ability to obtain various projections using 3D MRA may improve surgical planning.

Adolescent↗
PubMed1992

Gd-DTPA as an intestinal contrast agent for MR imaging of the lower abdomen: phase III clinical trial.

Thirty-one patients were investigated with magnetic resonance (MR) imaging of the lower abdomen before and after the administration of gadopentetate dimeglumine (Gd-DTPA) solution per os or per rectum or from both routes for the opacification of the intestinal tract. The parameters evaluated were: (a) contrast medium distribution, (b) degree of filling of the bowel lumen, (c) contrast between the bowel lumen and the surrounding normal or pathological structures, and (d) whether the administration of the contrast agent improved the diagnostic ability of MR compared to computed tomography (CT) or plain MR of the same region. Gd-DTPA, at a concentration of 1 mmol/L, produced a positive signal irrespective of its dilution in the bowel and good contrast between the bowel lumen and the adjacent tissues or any possible pathological lesions. From the diagnostic point of view, after the administration of contrast medium, MR is comparable to CT and much superior to plain MR. It is concluded that opacification of the bowel with Gd-DTPA solution will improve the diagnostic yield of MR imaging of the lower abdomen.

Abdomen↗
PubMed1991

Low back pain due to extramedullary hemopoiesis.

Two cases of extramedullary hemopoiesis in the lower spinal column are reported. One of them was due to thalassemia major and the other to thalassemia intermedia. CT and MRI studies showed paraspinal and presacral masses respectively which caused nerve root compression. It is concluded that the differential diagnosis of low back pain and radicular or pseudoradicular pain should include extramedullary hemopoiesis.

Adult↗
PubMed1991

CT appearance of pulmonary hydatid disease.

The principal features of computed tomography in hydatid disease of the lungs were reviewed in ten patients with surgically verified hydatid disease of the lungs. On the basis of localization and multiplicity, hydatid cysts of the lungs can be classified in three distinct categories: single unilateral unilocular cysts with or without daughter cysts, unilateral multiple cysts with or without daughter cysts, and bilateral multiple cysts. Cystobronchial communication may lead to cavitary lesions, while infection of the cyst may alter the attenuation values and produce a solid appearance. On the basis of density and clinical symptoms, hydatid cysts of the lungs can be classified as simple cysts, complicated cysts, and ruptured cysts, including cystobronchial communication.

Adolescent↗
PubMed1991

Congenital A-V fistula of the breast.

A case of congenital A-V fistula in the breast of a young woman is presented. The chief complaint was murmur when lying down, especially in the prone position, a palpable lump and the presence of varicose-like veins in the breast. Arteriography revealed an A-V fistula in the left breast. The arterial supply originated from the ipsilateral internal mammary vein and superior thoracic artery and drainage was towards the axillary vein and, to a minor degree, towards the internal mammary vein. The lesion was corrected surgically. Six months later there was no evidence of recurrence.

Adult↗
PubMed1991

Control of haematuria with superselective embolization.

Fifteen patients with severe haematuria due to causes other than malignant disease were seen between 1981 and 1989. Arteriography was done in an attempt to treat these patients with superselective embolization. In 7 patients, the cause of bleeding was due to injuries of iatrogenic origin and of the remaining 8, 2 had been in a car accident, 2 had knife stabwounds, 3 angiomatous malformations and 1 tuberous sclerosis. Twelve of the 15 patients were treated successfully with superselective embolization with steel coils. We consider angiography followed by superselective embolization to be the method of choice for the diagnosis and treatment of haematuria due to renal injury or other benign conditions.

Adolescent↗
PubMed1990

Masses of myeloadipose tissue: radiological and clinical considerations.

The records of 30 patients presenting radiological evidence of masses of extramedullary myeloadipose (hemopoietic) tissue, 25 patients suffering from thalassemia, one from sickle-cell anemia, and one from myelofibrosis were studied. Three patients presented with primary myelolipomas. Most of the patients with thalassemia presented with masses of hemopoiesis in the costovertebral angle and five patients presented with spinal cord compression. Magnetic resonance imaging is the best method for visualization and assessment of the extent of the masses in the thorax and spinal canal. Radiotherapy is the treatment of choice for spinal cord compression. One patient with thalassemia and one patient with myelofibrosis presented with masses of extramedullary hemopoiesis in the adrenals. All five patients with masses of myeloadipose tissue in the adrenals were treated surgically.

Adolescent↗
PubMed1990

CT and MRI of symptomatic spinal involvement by extramedullary haemopoiesis.

Five cases of tumour-like extramedullary haemopoiesis (EH) causing spinal cord compression or back pain are reported. Three patients were suffering from thalassaemia major, one from sickle cell anaemia and one from thalassaemia intermedia. CT findings included soft tissue masses in the epidural space of the spinal canal, spinal cord displacement and involvement of the underlying bone. MRI studies showed masses compressing the spinal cord. On T1-weighted images there was a signal of slightly higher intensity compared to that of the adjacent marrow. CT suggested the diagnosis in four cases (in the fifth it was not performed), while MRI was positive in all five. There was good correlation between the MRI findings and the CT appearance of the EH masses. Our results suggest that MRI may eliminate the need for other diagnostic examinations in the investigation of patients with EH.

Adult↗
PubMed1989

Features of computed tomography in hydatid cysts of the urinary tract.

The features of computed tomography (CT) in 5 patients with hydatid disease of the urinary tract are described. The diagnosis of hydatid disease was based on the demonstration of unilocular or multilocular cysts with well defined walls which enhanced with contrast, which were often calcified and which contained daughter cysts within the large parent cyst. It is difficult to differentiate between a unilocular hydatid cyst without mural calcification and an infected simple renal cyst.

Adult↗
PubMed1989

Investigation of renovascular hypertension with 99mTC-DTPA dynamic renal scanning and digital subtraction angiography.

Sixty-four selected hypertensive patients, aged 17-45 years, were evaluated for renovascular hypertension. They were studied with 99mTC-DTPA Dynamic Renal Scanning (DRS) and Intravenous Digital Subtraction Angiography (IV-DSA). Intra-arterial DSA was further performed to demonstrate renal vascular anatomy in all disputable cases. Agreement of diagnosis occurred in 58 patients (32 with renal artery stenosis). There was one false positive with DRS and one false positive with IV-DSA. In another four patients with proven renovascular disease, IV-DSA was positive while DRS negative, but in two of them the stenotic lesion was considered insignificant, as they failed to respond to percutaneous transluminal dilatation (PTA). In contrast, nearly all patients whose hypertension improved after PTA or surgery had positive DRS and greater than 40% reduction of relative function of the affected kidney. IV-DSA yielded better results than DRS in the detection of renal arterial stenosis (especially whenever bilateral stenosis or rich collateral circulation was present), but DRS showed better correlation with the functional significance of a certain vascular abnormality. Thus the combination of the two methods seems to be a reasonable diagnostic approach to hypertensive patients with the aim of selecting those with curable hypertension due to renal vascular disease.

Adolescent↗