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Biomedical subjects

G Krol

Publications and source records attributed to G Krol.

At least 55 records · Page 3Linked to original sources
PubMed1988

Intramedullary disease of the spine: diagnosis using gadolinium-DTPA-enhanced MR imaging.

Twenty-six patients with suspected lesions of the spinal cord were studied before and after administration of gadolinium-DTPA to assess whether contrast enhancement was useful in the MR evaluation of intramedullary disease. Nine patients had primary tumors, six had benign syringes, three had multiple sclerosis with cord involvement, three had thrombosed vascular malformations, three had probable intramedullary metastasis, and two were normal. Although all lesions were detected on noncontrast MR scans, gadolinium-DTPA was of great help in their delineation and characterization. Specifically, contrast material may be able (1) to localize tumor nidus and separate it from edema, in cases of hemangioblastomas and metastases; (2) to suggest regions of more active tumors, in cases of glioma, for surgical biopsy or removal; (3) to differentiate benign or reactive processes from neoplastic lesions, such as reactive cyst from tumor cyst or hematoma due to thrombosed malformation from tumor hemorrhage; and (4) possibly to differentiate active from inactive lesions, for example, in multiple sclerosis. Because of these advantages, gadolinium-DTPA probably will often be used routinely when intramedullary lesions are detected on noncontrast MR scans.

Adult↗
PubMed1988

Percutaneous electrocoagulation of the trigeminal nerve using CT guidance. Technical note.

Computerized tomography guidance can be used during placement of an electrode for the ablation of the trigeminal nerve or gasserian ganglion. A combination of a scout view and axial images through the skull base provides adequate visualization of the needle and foramen ovale. This method is recommended in patients who cannot be properly positioned for fluoroscopy or when there is poor visualization of the foramen on conventional radiographs.

Electrocoagulation↗
PubMed1988

Comparison of ciprofloxacin assays.

Two high pressure liquid chromatography methods developed independently and two different microbiological methods assayed samples containing ciprofloxacin derived from four volunteers: 46 sera, 19 saliva and 27 urine specimens. Each subject had received 500 mg of ciprofloxacin by mouth, with the samples collected in the ensuing six hours. Fifteen mock unknowns, prepared by adding known amounts of ciprofloxacin to normal human serum, were also assayed by the four procedures. The limits of sensitivity of the HPLC assays were less than 0.01 microgram/ml; the sensitivity limits of the bioassay were 0.02 microgram/ml (disc method) and 0.06 microgram/ml (well method). The inter-assay data was analyzed by linear regression. Ciprofloxacin concentrations in serum samples correlated well (R = 0.90) with all methods. Values obtained with urine samples also correlated well (R greater than or equal to 0.80). We conclude that either microbiological assay or quantitation by HPLC is satisfactory for quantitation of ciprofloxacin.

Chromatography, High Pressure Liquid↗
PubMed1987

Surgical treatment of spinal chordomas.

The clinical features and results of 34 patients with chordomas treated over a seven-year period were analyzed. Surgical treatment consisted of wide local excision (n = 6), marginal resection (n = 5), intralesional resection (n = 20), and biopsy (n = 3). Eighteen patients received postoperative radiotherapy. The local recurrence rate was 65%, with 30% of patients developing distant metastases. With the introduction of computed tomography, smaller tumors are currently being diagnosed; as a result, 35% of the patients in this series are disease free, compared with 10% described previously.

Adult↗
PubMed1987

Nimodipine disposition and haemodynamic effects in patients with cirrhosis and age-matched controls.

Six biopsy proven cirrhotics and five age-matched controls (mean 55.3 vs 52.4 years) were randomly given single 60 mg p.o. and 30 mg s.l. doses of nimodipine. Serum concentrations and blood pressure were measured regularly over the subsequent 24 h period. The clearance of nimodipine was reduced in the patients with cirrhosis. Apparent oral clearance of nimodipine in the cirrhotic group was significantly lower than that observed in the normal group (187 +/- 163 l h-1 vs 469.6 +/- 198.4 l h-1, P less than 0.01). There were no significant changes in mean arterial pressure (MAP) in the normal subjects. There were, however, significant reductions in MAP following oral nimodipine in the cirrhotics. These reductions were significantly related to nimodipine concentrations in individual patients (P less than 0.05).

Adult↗
PubMed1987

Hemorrhagic neoplasms: MR mimics of occult vascular malformations.

The MR scans of 24 patients who had findings previously reported to be characteristic of occult cerebral vascular malformations were reviewed to demonstrate that such findings may also occur in primary or secondary neoplasms. Eighteen of the 24 patients were found to have hemorrhagic neoplasms. Additional criteria, such as multiplicity of lesions and the presence of edema, were of some help in differentiating between occult vascular malformation and hemorrhagic neoplasm. In certain cases, CT was necessary to provide further information, such as the presence of calcification; however, an absolute and accurate diagnosis was impossible in several cases. The striking similarity on MR between cryptic vascular malformation and some hemorrhagic neoplasms is most likely due to the unifying mechanisms that underlie the evolution of extravascular intracerebral blood. Although the preponderance of neoplastic etiologies in our series may be partly due to the strong bias in our sample population toward patients with tumors, it seems clear that when an MR scan discloses findings "typical" of an occult vascular malformation, consideration must also be given to the generally more serious possibility of underlying neoplasm.

Adolescent↗
PubMed1986

Postradiation sarcoma involving the spine.

Postradiation sarcomas arising many years after treatment of cancer are long term sequelae of therapy. We describe the clinical features, radiographic findings, and results of treatment in 13 patients with such sarcomas encountered over a 6-year period. Of these patients, 9 had bone sarcomas and the remaining 4 had paraspinal tumors arising from adjacent soft tissue and nerve. The primary cancer for which radiation was given included Hodgkin's disease (4 patients), breast cancer (2 patients), cervix cancer (2 patients), and a variety of others (5 patients). The latent interval to the occurrence of the second neoplasm varied from 6 to 30 years (median, 10 years) after treatment of the original tumor. Despite aggressive treatment, the overall prognosis was poor. The median survival was 8 months, with only 3 surviving more than 2 years. Although rare, postradiation sarcoma should be considered in the differential diagnosis of patients presenting with late onset of spinal pain or neurological symptoms after clinical remission of an original cancer.

Adolescent↗
PubMed1986

Light dosimetry in animal models: application to photodynamic therapy in otolaryngology.

Photodynamic therapy (PDT) for treatment of head and neck cancer uses a photoactive compound that is illuminated with 630 nm (red) light. The effectiveness of PDT depends on the penetration of light into tissue that is both tissue and wavelength dependent. The characterization of the optical properties of an animal oral mucosa and skin has been done to determine the amount of light below these tissues available to be used for photodynamic therapy. The tissue absorbance of visible light from 400 nm to 700 nm has been determined in vitro for hamster check pouch mucosa and for athymic mouse skin. The pattern of absorbance is similar for both tissues and demonstrates greater transmission at the longer wavelengths. The diffuse transmittance of light in vivo for these animal models was measured with an interstitial fiberoptic probe. At 630 nm the diffuse transmittance for nude mouse skin averages 10% of the incident light energy, and that for the hamster mucosa almost 50% of the incident light energy.

Animals↗
PubMed1986

Value of magnetic resonance imaging in the evaluation of patients with complete and high degree block due to intracanal neoplasm.

Magnetic resonance imaging (MRI) of 26 patients with high degree or complete epidural and/or intradural myelographic block, due to primary or secondary neoplasm were analysed. The ratio of false negative MRI was 11.5 per cent. MRI findings were considered to be indicative of lesser block than indicated by myelography in almost 50 per cent of patients. Correlation between the two modalities was highest in cases associated with significant vertebral collapse, malalignment and angulation of the spine and angulation of the spinal cord.

Humans↗
PubMed1986

Computed tomography of head and neck malignancies.

This article briefly describes the clinical features of the most common malignant neoplasms of the head and neck region. The diagnostic approach and contribution of computed tomography is discussed. CT is presently considered the method of choice in noninvasive evaluation of these neoplasms.

Adolescent↗
PubMed1985

Evolution of computed tomographic abnormalities in leptomeningeal metastases.

We obtained serial cranial computed tomographic (CT) scans from 25 patients with documented leptomeningeal metastases in order to correlate the course of clinical symptoms and cerebrospinal fluid abnormalities with the evolution of CT abnormalities. In almost one-third of patients, relatively specific CT findings such as enhancement of the meninges, obliteration of cisterns or sulci, and hydrocephalus with transependymal edema preceded clinical symptoms. By the time patients became symptomatic, 10 of 25 (40%) had specific abnormalities, and 4 more became specifically abnormal with time. The first scan after cerebrospinal fluid tumor cells were discovered showed specific abnormalities in only 6 patients, but 7 more became specifically abnormal with time. Ventriculomegaly occurred in 18 of 25 patients (72%) and was associated with sulcal and/or cisternal obliteration in one-half of the patients. In 4 patients sulcal and cisternal obliteration developed prior to ventricular enlargement. Multiple small, enhancing cortical nodules were detected prior to symptom onset and discovery of leptomeningeal tumor in 5 patients.

Arachnoid↗
PubMed1983

Computed tomography of axial chordomas.

Preoperative computed tomography (CT) of 19 patients with axial chordomas was reviewed. These tumors characteristically feature a well-demarcated paraspinal soft tissue mass which is usually anterolaterally situated and has a homogeneous density comparable to that of muscle. The soft tissue component is disproportionately large compared to the area of bony involvement. Lytic or mixed vertebral lesions were noted. Amorphous calcifications that tended to occur at the periphery of the tumor were particularly common (89%) in chordomas of the sacrum. Epidural extension of tumor was noted in all spinal cases. Although it appears that CT studies will generally not enable a specific diagnosis of chordoma, the above features should alert the examiner to the possibility of this tumor.

Adult↗
PubMed1983

CT of the brachial plexus in patients with cancer.

To assess the usefulness of CT, we reviewed 51 patients with clinically diagnosed brachial plexopathy who were seen between 1977 and 1981. The established etiology was metastatic tumor in 46 and radiation fibrosis in 5. CT was abnormal in 89% of tumor patients. Myelography, bone scan, and plain cervical spine radiographs were less useful. In four of five patients with radiation fibrosis, CT showed distortion of normal tissue planes without a discrete mass, but was not always distinguishable from tumor infiltration. CT of the brachial plexus provides the best two-dimensional view of tumor infiltration and detects bony changes earlier than standard radiographs. CT is a useful guide for surgical exploration of the brachial plexus, but does not differentiate tumor infiltration from radiation fibrosis.

Brachial Plexus↗
PubMed1981

Computerized tomography findings in multifocal glioma.

Six patients with multifocal glioma are presented. Computerized tomography revealed multiple, discrete, contrast-enhancing lesions in the cerebral hemispheres, suggestive of multiple intracranial metastases. The most accessible lesion was resected at craniotomy in each patient, confirming the diagnosis of primary malignant glioma. Postoperative radiation therapy and chemotherapy were instituted according to current protocols. Since neuroradiological studies may not allow distinction of multifocal glioma from multiple brain metastases, surgical biopsy is suggested in those patients who have no history of cancer.

Aged↗
PubMed1979

Carcinoma of choroid plexus in a premature infant.

A histologically proven case of choroid plexus carcinoma in a 5-week-old infant is presented. Computed tomography showed invasion through the ventricular wall, suggesting its malignant nature.

Adenocarcinoma, Papillary↗
PubMed1978

CT of the spine.

The level of CT section in the lumbosacral region may be correlated with routine AP views of the spine using a reference plane constructed according to the distance between the iliac crests. CT scans of the spine in 100 patients have been analyzed. The majority of these cases consisted of primary or secondary bone or soft-tissue tumors. CT examination was valuable to supplement plain films and/or myelograms in evaluation of the extent of pathology. It was also useful in the work-up of patients with malignant tumors whose other studies were equivocal.

Humans↗