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C Nasel

Publications and source records attributed to C Nasel.

30 records · Page 2Linked to original sources
PubMed1998

Technetium-99m-MIBI in primary and recurrent head and neck tumors: contribution of bone SPECT image fusion.

UNLABELLED: We prospectively investigated 200 patients with the clinical suspicion for head and neck tumors. The final diagnoses were 94 primary and 56 (37 confirmed, 19 excluded) recurrent squamous cell carcinomas (SCCs), 3 primary and 7 (4 confirmed, 3 excluded) recurrent adenoid cystic carcinomas (ACCs), 6 non-Hodgkin's lymphomas, 10 distant metastases, 6 other malignancies, 10 inflammatory and 8 other nonmalignant conditions. METHODS: Bone (600 MBq 99mTc-3,3-diphosphono-1,2-propane dicarboxylic acid tetrasodium salt) and hexakis-2-methoxyisobutyl isonitrile (MIBI) (600 MBq 99mTc-MIBI) SPECT were both performed under identical conditions (triple-head gamma camera; ultra-high-resolution, parallel-hole collimators; three-dimensional postfiltering) and judged independently and after superimposition. The results were compared to the results of biopsy, surgery and CT. RESULTS: The overall sensitivity/specificity of MIBI was 90%/78% for tumor detection and 90%/95% for the identification of malignant lymph node involvement (CT: 79%/66%, respectively 90%/79%). In the subgroup of recurrent SCC and ACC the sensitivity/specificity for tumor detection was 95%/71% for MIBI versus 78%/68% for CT. The isolated assessment of bone SPECT had a sensitivity/specificity of 100%/17% for osseous tumor spread. Image fusion of MIBI and bone SPECT differentiated between regio-local bone involvement and inflammatory changes and increased the specificity of bone SPECT to 100% in primary staging. Tumor size, stage, histology and pretreatment had no statistically significant effect on tracer uptake or diagnostic utility of scintigraphy. CONCLUSION: We propose the combined 99mTc-MIBI and bone ultra-high resolution SPECT as a highly useful imaging approach in the primary and secondary staging in patients with suspected malignancies in the head and neck region. The high specificity for malignancies in the head and neck region may be used in the differential diagnosis between head and neck malignancies and inflammatory disease in patients with the accidental finding of enlarged lymph nodes and no clinical signs of a primary tumor. Image fusion with bone scanning is mandatory for the topographical orientation and increases the specificity of bone scanning to differentiate between inflammatory or malignant causes of increased bone metabolism.

Bone Neoplasms↗
PubMed1997

Tumour blood flow and partition coefficients: correlation with grade of cerebral gliomas using xenon-enhanced computed tomography.

It is possible to underestimate the grade of nonenhancing cerebral tumours on conventional contrast-enhanced MRI or CT. Differentiation of high- and low-grade gliomas by measurement of the brain-blood partition coefficient lambda (T lambda) with Xe-enhanced CT (XeCT) has been reported. We assessed the practical applications of XeCT in suspected low-grade astrocytomas. We examined 15 patients with tumours which showed no contrast enhancement on conventional MRI and CT, using XeCT. Tumour blood flow (TBF) and T lambda were calculated. Fourteen patients underwent surgery, one patient had a biopsy. We recognized three histological groups. While T lambda differed significantly between them, TBF did not. Group 1 contained grade II-III astrocytomas and T lambda was 0.77; group 2 contained grade I-II astrocytomas with T lambda 1.14, and group 3 four oligodendrogliomas in which a T lambda of 1.50 was found.

Adolescent↗
PubMed1996

Histological heterogeneity of neuroradiologically suspected adult low grade gliomas detected by Xenon enhanced computerized tomography (CT).

Xenon-enhanced computerized tomography (XeCT) was performed on 14 consecutive adult patients presenting with seizures showing supratentorial non-enhancing radiologically uniform appearing low grade gliomas on CT/MR images. Pre-operative XeCT patterns were compared with postoperative histological diagnosis, grading and Ki67 proliferation indices (PI). After gross-total, subtotal resection or biopsy, 11 astrocytomas, 2 oligodendrogliomas and 1 oligo-astrocytoma were diagnosed and graded: Grade I: 2 patients (Ki67-PI = 0.5-0.8), Grade I-II: 4 patients (Ki67-PI = 0.3-1.5), Grade II: 3 patients (Ki67-PI = 0.5-3.5), Grade II-III: 4 patients (Ki67-PI = 3.8-6.8) and Grade III: 1 patient (Ki67-PI = 5.2), (Kernohan Classification). Xenon CT studies revealed different flow patterns, correlating with the postoperative histological diagnosis, grading and proliferation indices: A tumour group with well defined, delayed, only minimally enhancing tumour area (5 patients, Grade I, I-II or II), a second group with less well defined low-flow-area borders and inhomogenous, strong enhancement within the tumour (4 patients, Grade II-III, III) and a third group with fast enhancing tumours was identified. The third pattern was exclusively shown in the 2 oligodendrogliomas (Grade I and II-III) and 1 oligo-astrocytoma (Grade II). The preliminary report identifies the Xenon enhance CT as a beneficial pre-operative investigation for patients with radiologically uniform appearing suspected adult supratentorial low-grade gliomas, which may give information about the presence of anaplastic foci or oligodendroglial components.

Adolescent↗
PubMed1996

Stable xenon CT in patients with chronic cerebrovascular disease.

Xenon-enhanced CT (XeCT) is a method of measuring regional cerebral blood flow (rCBF). Although it is used for acute and perioperative assessment the ability of XeCT to show hypoperfused areas in vivo, as compared with morphological imaging modalities other than noncontrast CT, is not defined. Correlation with MRI helps to define the smallest detectable hypoperfused area. We examined 17 patients 6 weeks after acute cerebral infarcts with CT, XeCT and MRI and the findings were compared. All examinations were performed with the same slice angulation and thickness and the sizes of the abnormal areas were measured. XeCT showed a high correlation with MRI, but less so with conventional CT. Lesions appeared significantly smaller on CT than on XeCT or MRI. No significant difference between MRI and XeCT changes was found. The minimal lesion on MRI correlating with a hypoperfused area on XeCT was 0.8 cm2, whereas lesions measuring less than 0.5 cm2 on MRI could not be detected on XeCT. The good correlation between XeCT and MRI underlines the reliability of rCBF examinations with XeCT. A significant difference between CT and XeCT findings shows the difficulty of interpreting hypoperfused regions only by correlation with CT. Combined XeCT and MRI gives a better estimate of the vascular state of the brain.

Aged↗
PubMed1996

[CT and MRI of small intestine interposition after oropharyngeal tumor resection].

Freely transplanted, microvascularly anastomosed jejunal patches can be used to cover soft tissue defects in the oral cavity or oropharynx after the resection of malignant tumors. Even a patch without complications or alteration from tumor recurrence is morphologically diverse. Therefore it is difficult to distinguish between malignant and benign alterations, and knowledge of the possible morphological spectrum and the significance of an alteration is of practical interest. Computed tomography (CT; n = 30) and magnetic resonance imaging (MRI; n = 13) were used for follow-up examinations in patients who had an operative reconstruction with a jejunal patch. Three parts of a patch were differentiated with both imaging modalities: the region of the anastomosis, the mesenterial fatty tissue and the intestinal wall. The morphology of the patches correlated with clinical findings in the following cases. The patches were identified satisfactorily by CT and MRI. The appearance of patches without complications was influenced by a variable degree of fibrosis and by persistent intestinal folds. Recurrent tumors only infiltrated the margins of the patches. Destructive alterations in the patches were always less severe than those in the original orofacial soft tissue. Postoperative follow-up examinations with CT and MRI are particularly important when tumor recurrences spread under a patch, since these tumors are invisible in the clinical examinations. CT was advantageous in demonstrating osseous alterations and showed less loss of image quality in patients for whom the implantation of multiple metallic hardware during the operation had been necessary.

Adult↗
PubMed1996

Pharmacokinetic studies of the fragrance compound 1,8-cineol in humans during inhalation.

The present study was undertaken to investigate the pharmacokinetics of 1,8-cineol in human subjects during prolonged inhalation. The results showed that 1,8-cineol is well absorbed from breathing air, with a peak plasma concentration after approximately 18 min. The elimination of this fragrance compound from the blood is biphasic, with a mean distribution half-life of 6.7 min and an elimination half-life of 104.6 min.

Administration, Inhalation↗
PubMed1996

Power Doppler versus color Doppler imaging in renal allograft evaluation.

The purpose of this study was to evaluate the impact of PDS compared to conventional CDI in the followup of 72 renal allograft patients. Renal allograft vascularization, assessed by PDS and CDI, was scored from 0 to 4, where 0 was the cortical "blush" and 4 was residual central perfusion. These scores were correlated with the resistive index, serum creatinine levels, hematocrit, and, in 35 cases, biopsy results. PDS scores of renal perfusion were one grade lower than CDI scores in 59 of 72 patients and two grades lower in two of 72 patients. A statistically significant correlation was found between PDS scores and the RI (r2 = 0.6, P < 0.05). However, no significant correlation was found between PDS scores and creatinine levels or hematocrit values. PDS scores are not related to histologic findings in renal allograft dysfunction. Overall, five biopsy-related arteriovenous fistulas were detected, two of which were missed on the initial PDS examination. In conclusion, PDS provides more complete visualization of the renal allograft vessel tree than CDI. However, biopsy-related arteriovenous fistulas are better seen by CDI.

Biopsy↗
PubMed1996

Bone metastasis with superimposed osteomyelitis in prostate cancer.

The following case of a male patient with a history of prostate cancer suffering from pain and swelling in the right mandibular area illustrates the well-known diagnostic problem of a superinfected tumor. Orthopan tomography and CT showed no defects in bone structure or smooth tissue. Whole-body bone scanning showed increased tracer uptake in the mandibular bone and in several other locations in the skeletal system. Antigranulocyte immunoscintigraphy showed increased uptake over the right mandible, whereas the other metastatic sites were visualized as cold spots. A second CT scan depicted a sclerotic lesion with surrounding periostal reaction and soft-tissue swelling and was interpreted as osteomyelitis. Therefore, clinical symptoms, bone scanning, antigranulocyte immunoscintigraphy and follow-up CT resulted in a diagnosis of osteomyelitis, although open needle biopsy revealed the lesion to be prostate cancer metastasis with massive leukocytic invasion.

Antibodies, Monoclonal↗
PubMed1994

Functional imaging of effects of fragrances on the human brain after prolonged inhalation.

Beside olfactory or trigeminal stimulation of chemosensory receptor-cells some results in published literature suggest that fragrances show a direct affect on the brain. The effect of the fragrance 1,8-cineol, which was described in literature as 'stimulating', on regional and global cerebral blood flow (rCBF and gCBF) in the human brain after prolonged inhalation was investigated. The results show an increase of global-CBF without preference to primary or secondary olfactory centres after an inhalation-time of 20 min.

Adult↗
PubMedDate not supplied

Dental MR tomography of the mandible.

Imaging of the jaw bones is routinely achieved by conventional X-ray tomography or CT. In this study a new imaging procedure (dental MR tomography) is introduced. Five subjects were positioned in the standard neck coil of a 1.0 T MR scanner, and T1- and T2-weighted imaging of the mandible was performed in the axial plane. After the examination, the data were reconstructed as panorama and cross-sectional images using a software package for dental imaging on a workstation. The neurovascular bundle within the mandibular canal (MC), its relation to the teeth, and the pulp chambers of the teeth were demonstrated excellently in all cases. Edema and reactive hypervascularization due to an inflammatory process were also well visible. Dental MR tomography could become a good alternative to X-ray-based imaging modalities of the jaw bones by additionally offering the advantage of directly imaging the neurovascular bundle within the MC. Furthermore, administration of contrast agent for differentiation of pathological alterations is possible.

Adult↗
PubMedDate not supplied

Measurement of time-to-peak parameter by use of a new standardization method in patients with stenotic or occlusive disease of the carotid artery.

BACKGROUND AND PURPOSE: A quantitative, easily obtained measure of cerebral hemodynamics would be valuable in planning surgical or interventional therapy for patients with stenotic or occlusive disease of the carotid artery. We evaluated the recently introduced standardized time-to-peak variable (stdTTP), obtained with dynamic susceptibility contrast-enhanced MR (DSC-MR) imaging, in different states of stenotic/occlusive carotid artery disease. METHODS: We examined 24 patients with unilateral, high-grade stenosis (85%-95%) of one internal carotid artery (ICA) and 10 patients with stenosis (85%-95%) of one ICA and occlusion of the contralateral ICA. Mean stdTTP was evaluated in the central vascular territories of the anterior, middle, and posterior cerebral arteries and the anterior and posterior border zones and compared with the mean stdTTP values from 36 cerebral hemispheres without hemodynamic impairment. RESULTS: Patients showed no significant prolongation of stdTTP in the central vascular territories compared with the reference group, whereas significant prolongations of stdTTP were measured in the anterior and posterior border zones in patients with ICA disease (ANOVA, P <.05) and were most prominent in higher grades of carotid disease. Hemispheres with hemodynamic impairment always showed a stdTTP > 3.5 s in the border zones. CONCLUSION: The StdTTP quantitatively describes the hemodynamic impairment in cerebral hemispheres supplied by a stenosed or occluded ICA. An stdTTP value of > 3.5 s, as has been postulated, seems to point out hemodynamic impairment.

Aged↗