Search PubMed⌕ Search

Biomedical subjects

C Reinhold

Publications and source records attributed to C Reinhold.

At least 73 records · Page 4Linked to original sources
PubMed1988

Replaced or right accessory hepatic artery: can ultrasound replace angiography?

The accuracy of ultrasonography in detecting the right hepatic artery was prospectively assessed in 128 patients undergoing abdominal angiography. Twenty-five (19%) of the ultrasound studies were technically inadequate mainly because of gas superimposition. Of the remaining 103 cases, 14 had a replaced hepatic artery, which was diagnosed in 10 cases with ultrasound (sensitivity 71%). Eighty-nine did not have a replaced hepatic artery and the ultrasound assessment was falsely positive in four of them (specificity 96%). Two of the four false negative results could be explained by a stenosis of the superior mesenteric artery in front of the origin of the replaced hepatic artery. Two of the four false positive results could be explained by the presence of a stenosis of the celiac trunk with hypertrophy of the pancreaticoduodenal arteries, one of them being misdiagnosed as a replaced hepatic artery.

Angiography↗
PubMed1987

Magnetic resonance imaging evaluation of radiation-induced changes in experimentally implanted renal cell carcinoma.

The effect of radiation on the magnetic resonance imaging appearance and relaxation parameters of human renal cell tumors implanted in male white-Swiss athymic nude mice was evaluated. Twenty-three mice were treated with external beam radiation, receiving a total dose of 2,500 rads administered in a single treatment limited to subcutaneous tumor. Twenty-two tumor-bearing mice served as control animals. Experimental and control mice were studied with MRI at four (n = 9), seven (n = 20), 14 (n = 8), and 28 (n = 8) days following experimental radiotherapy. A 0.35 tesla superconductive MRI system was employed. Images were generated using spin-echo technique with repetition times (TR) of 500 and 2,000 ms and echo-delay times (TE) of 28 to 30 and 56 to 60. Relaxation time calculations were made on the basis of tumor signal-intensity measurements in assigned regions of interest. The MRI appearances and relaxation times of irradiated tumors that decreased in size following treatment, irradiated tumors that grew, and control tumors were similar, as were their histologic features. No statistically significant differences could be detected in relaxation times of the four experimental and four control groups. Statistical evaluation was performed using analysis of variance. Further investigation of MRIs potential in tissue characterization following radiotherapy is warranted, but evaluation of change in tumor dimensions remains the most reliable indicator of therapeutic response.

Animals↗
PubMed1986

Uterine leiomyomas: correlation of MR, histopathologic findings, and symptoms.

Magnetic resonance (MR) imaging, symptoms, and pathologic findings were correlated in 59 uterine leiomyomas from 23 patients. The tumors varied from less than 1 cm to 18 cm in diameter. Fifty-seven leiomyomas were identified in the corpus uterus, one was located within the broad ligament, and another was detected in the cervix. Among the corpus lesions, 9 were correctly identified on MR images as subserosal and 37 as intramural. Of 11 tumors assigned at surgery to the submucosal group, 10 had been accurately defined with MR. On MR, myomas associated with hypermenorrhea produced an anatomic disruption of the "junctional zone" (the low-intensity band seen at the myometrium-endometrium junction on T2 contrast images). Long TR (2 sec) and TE (56 msec) parameters (T2 contrast images) yielded the best contrast resolution between leiomyoma and surrounding myometrium. Correlation of MR with histologic features demonstrated 2 groups of lesions. Leiomyomas free of degenerative changes emitted homogeneous signals of low intensity. Contrast between tumor and myometrium was -16% on the T1 contrast image and increased to -44 +/- 16% on the T2 contrast image. Leiomyomas with hyaline, myxomatous, or fatty degeneration demonstrated various degrees of inhomogeneity, best seen on images obtained with long TR and TE. It is concluded that MR is an accurate modality for imaging uterine leiomyomas, since it clearly demonstrates tumor number, size, location, and the presence and extent of degeneration.

Adipose Tissue↗
PubMed1981

Microspectrofluorometric study of monoamines in the auricle of the heart of Protopterus aethiopicus.

The auricle of the heart of Protopterus aethiopicus contains large numbers of chromaffin cells, often lying immediately adjacent to the endothelium and displaying a bright blue-white fluorescence characteristic for catecholamines after formaldehyde treatment (Falck and Owman 1965). These results combined with X-ray microanalysis after initial fixation with glutaraldehyde and subsequent treatment with dichromate established that these chromaffin cells are the storage site of primary catecholamines (Scheuermann 1978, 1979, 1980; Scheuermann et al. 1980). The aim of the present pilot study was to demonstrate in these cells noradrenaline (NA) or dopamine (DA), or a mixture of both. The evaluation of the excitation spectra of the catecholamine fluorophore transformed by treatment with HCl vapour (excitation maxima at 320 and 370 nm) and the excitation-peak ratio analysis (peak ratio 370/320 nm = 1.05-1.5; and 320/280 nm greater than 1.5) identify DA as the primary catecholamine stored in these chromaffin cells. The low fading rate of the monoamine fluorescence after acidification confirms the presence of DA. These microspectrofluorometric findings demonstrate that chromaffin cells in the auricle of the Protopterus heart, which are a part of the medullary homologue of the adrenal gland of higher vertebrates, contain a primary catecholamine, namely DA.

Animals↗
PubMed1980

A rapid method for measuring drug enrichment in epidermis.

A rapid and simple method is described for measuring the enrichment of small molecules in epidermal tissue. To measure such an enrichment, a small tissue sample (2-10 mg) is allowed to equilibrate with a buffered solution of a labelled substance for periods of 12-36 h. The concentration of the radioactive molecule in the tissue is measured as a decrease of radioactivity in the solution. Concentration measurements in the tissue itself can be performed, but are not required to detect enrichment in the tissue or to assess its magnitude. The specific density of appendage free human epidermis has been determined and was found to be 1.20 g/cm3. Using this value, tissue weight can be translated into volume and concentraton changes in the solution can be recalculated to yield the concentration of the substance in the tissue itself. Close agreement was found between the calculated tissue concentration and the values actually measured, following digestion of the epidermis with NaOH and measuring the activity in the tissue digest. The enrichment of five substances in human epidermis was measured: alpha-estradiol, thiopyronincce, 8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP), and theophylline. Of these substances, the first four are concentrated by human epidermis and the concentrations reached within the tissue are 10-500 times higher than the concentration of the same substance in the surrounding buffer. The enrichment data has been analysed in an attempt to distinguish between reversible affinity binding to specific tissue sites and partitioning of the substances between buffer and tissue components (lipids, membranes, etc.). In the case of thiopyronin and 8-MOP, reversible binding is indicated with dissociation constants of 10(-7) M and 10(-5) M, respectively, while partitioning distribution could account for the behavior of 5-MOP and alpha-estradiol. The method can be used either as a rapid screening method or as a quantitative analysis for the characterization of tissue enrichment with specific drugs.

Binding Sites↗
PubMed1979

Distribution patterns of formaldehyde-induced fluorescence of hypothalamic monoamines.

In a circumscribed area of the preoptic periventricular nucleus of a male rat, formaldehyde-induced monoamine fluorophores modified by treatment with HCl vapors were investigated microfluorometrically (measurement of excitation peak ratio 370 : 320 nm) in all fluorescent terminals and preterminals. Microfluorometric recordings of an individual fluorescent structure were performed without UV irradiation of neighboring fluorophores. Recorded data were sampled and corrected by a microcomputer (Wang PCS II). 19 neuronal processes (axons) contained noradrenaline fluorophores; 11 contained dopamine fluorophores; 6 exhibited uncharacteristic excitation peak ratios; and in 19 recordings technical problems did not allow identification of the fluorophore content.

Animals↗
PubMedDate not supplied

MR cholangiopancreatography: comparison between two-dimensional fast spin-echo and three-dimensional gradient-echo pulse sequences.

The purpose of our study was to perform a prospective comparative analysis of three-dimensional (3D) steady-state free precession (SSFP) and two-dimensional (2D) fast spin-echo (FSE) imaging in the evaluation of 26 patients with suspected bile duct obstruction. SSFP and highly T2-weighted FSE sequences were obtained for each patient in multiple planes. Both sequences were reviewed independently and results were compared with findings from direct cholangiography (n = 17) or from a combination of sonography and CT (n = 9). The extrahepatic bile duct [EHBD] and intrahepatic bile duct [IHBD] were dilated in 32% and 54% of patients, respectively. The EHBDs were visualized in 44% of patients with SSFP, versus in 96% with FSE. One or more IHBD segments were seen in 42% of the SSFP sequences and in 100% of the FSE sequences. A portion of, or the entire, pancreatic duct was seen in 23% of the SSFP sequences and in 65% of the FSE sequences. Our findings lead us to conclude that T2-weighted FSE sequences are superior to SSFP sequences in visualizing the biliary tree and pancreatic duct and that they should replace gradient-echo sequences in MR cholangiopancreatography.

Artifacts↗
PubMedDate not supplied

Pelvic fistulas: appearances on MR images.

BACKGROUND: This multi-institutional study examines appearances of pelvic fistulas on magnetic resonance (MR) images. METHODS: MR images of 46 patients with documented fistulas from five teaching hospitals were retrospectively reviewed. All patients underwent T1-weighted (T1WI), T2-weighted (T2WI), and intravenous gadolinium chelate-enhanced T1-weighted (Gd-T1WI) images. Imaging sequences were separately and then collectively reviewed. The following determinations were made: fistula detection, fistula morphology and signal intensity, and the presence of associated abnormalities. Fistulas were classified into two categories: (1) fistulas that communicate with the bladder and (2) fistulas that do not communicate with the bladder. Fistulas within these two groups were subclassified further. The presence of fistulas was documented by surgery (five patients), endoscopy (six patients), fistulogram (20 patients), or physical exam (15 patients). RESULTS: Among the 46 patients, 53 fistulas were documented by means other than MR. Overall T1WI, T2W1 and Gd-T1WI images demonstrated 23, 31, and 39 of 53 fistulas, respectively. Gd-T1W1 detected significantly more fistulas than T1W1 (p < 0.05). Bladder fistulas were better shown on Gd-T1WI (8/15 fistulas) than on T1WI and T2WI (2/15 and 3/15) (p < 0. 05). Nonbladder fistulas were demonstrated by T1WI, T2WI, and Gd-T1WI images in 21, 28, and 31 of 38 fistulas, respectively. Among all fistulas, perianal fistulas (a subcategory of nonbladder fistula) had the highest detection by T1WI, T2WI, and Gd-T1WI in 19, 20 and 22 of 23 fistulas, respectively. On T1WI, 19 of 23 detected fistulas were low in signal intensity. On T2WI, 28 of 39 detected fistulas were high in signal intensity. On Gd-T1WI images, 29 of 40 fistulas were low in signal intensity, with enhanced tract wall. CONCLUSION: Bladder fistulas were best shown on Gd-T1WI, which was significantly greater than on T1WI or T2WI. Nonbladder fistulas were comparably shown by all techniques, with all performing modestly well. Perianal fistulas were shown equally well by all MR sequences and were the fistulas demonstrated with the highest sensitivity on MR images.

Adolescent↗
PubMedDate not supplied

Effect of portal venous flow augmentation on liver enhancement with CT.

BACKGROUND: The purpose of this study was to evaluate the effect of portal flow augmentation on hepatic computed tomographic (CT) enhancement. METHODS: Thirteen patients undergoing follow-up CT of the liver within 6 months of initial study ingested 470 mL of Ensure 30 min before the second examination. Contrast medium injection and scanning parameters were identical for both studies. RESULTS: The time to peak and the maximum and mean liver enhancements were 68 s, 56 HU, and 46 HU, respectively, for the examinations without Ensure and 68 s, 53 HU, and 44 HU for the examinations with Ensure. No significant difference was found between the two groups when mean liver enhancement was calculated over 3-s time intervals. CONCLUSION: Portal venous flow augmentation induced by a meal had no effect on liver enhancement.

Contrast Media↗
PubMedDate not supplied

Hepatic CT enhancement: effect of the rate and volume of contrast medium injection in an animal model.

BACKGROUND: To evaluate the relative effect of rate of injection and volume of contrast medium on aortic, portal, and hepatic enhancement during computed tomography (CT). METHODS: Thirty-eight nonincremental CT examinations were performed in three mini-pigs by using a combination of three different volumes (1.5, 2, and 3 mL/kg) and five different rates (1.5, 3, 4.5, 6, and 7.5 mL/s) of contrast material injection. Time-density enhancement curves of the aorta, portal vein, and liver were plotted over time for each rate of injection, each volume of contrast, and each volume-rate combination. In addition, aortic, portal, and liver peak enhancements, time-to-peak enhancements, optimal scanning intervals, and contrast enhancement indices were calculated for each volume-rate combination. RESULTS: Higher rates of injection increased peak aortic enhancement but had no effect on peak portal or hepatic enhancement. This result may be explained by the dilution of the bolus of contrast medium in the splanchnic circulation. When the results of a 6-mL/s injection of 1.5 mL/kg of contrast material were compared with a 3-mL/s injection of 2 mL/kg, maximum aortic enhancement increased by 32%, whereas maximum liver enhancement decreased by 35%. CONCLUSION: An increase in the rate of contrast injection results in an increase of peak aortic enhancement even when the total iodine load is decreased. However, an increase of the rate of contrast injection does not increase maximum liver enhancement, which is related to the total iodine dose injected. Therefore, one cannot compensate a decrease in the iodine load by an increase in injection rate in contrast-enhanced CT of the liver.

Animals↗
PubMedDate not supplied

Dynamic enhancement of upper abdominal organs in normal volunteers with MRI and effects of contrast dose reduction.

BACKGROUND: To quantify enhancement parameters of the upper abdominal organs over time during magnetic resonance (MR) examinations and to evaluate the effect of a dose reduction of contrast medium on these parameters. METHODS: Ten volunteers underwent two separate dynamic enhanced MR examinations with 0.1 and 0.075 mmol/kg of contrast medium, respectively. Breath-hold gradient-echo T1-weighted images were acquired every second for 118 s followed by delayed images. The percentages of enhancement, the time to maximum enhancement, and the area under the time-versus-enhancement curve were calculated for each organ. RESULTS: The mean times to maximum percentage of enhancement were less than 25 s for the pancreas, kidneys, and spleen and 50 s for the liver. The mean values of maximum percentage of enhancement for the standard/reduced doses were 72%/62% (pancreas), 165%/155% (kidneys), 114%/87% (spleen), and 67%/53% (liver). This difference was significant when liver enhancement was considered (p = 0.02). In addition, when the areas under the time-versus-enhancement curves were compared, the difference between the standard dose and reduced dose was significant for all organs tested (p < 0.05). CONCLUSIONS: Dynamic scanning of the upper abdomen should start early after contrast injection. Injection parameters should be standardized to capture arterial and venous enhancements in liver examinations. A 25% dose reduction did not significantly affect peak enhancement (except for the liver) but did significantly reduce overall enhancement.

Adult↗
PubMedDate not supplied

Progress in microfluorometric identification of monoamine fluorophores.

Techniques for the microfluorometric identification of monoamine fluorophores have been put forward along two different lines: (1) extension of the excitation range into the far UV and (2) computer-assisted on-line scanning recordings in combination with an automatic microfluorometric identification of fluorophores. By an extension of the excitation range to 250 nm it is possible to distinguish fluorophores of DOPA from those of dopamine, fluorophores of noradrenaline from those of adrenaline, and fluorophores of 5-OH-tryptophan from those of 5-OH-tryptamine. In a computer-assisted on-line scanning procedure using a high-aperture inverted illuminating microscope equipped with UV transmitting optics the specific formaldehyde-induced catecholamine fluorescence is characterized microfluorometrically by corrected ratios of excitation maxima (370:320 nm and 320:275 nm). Excitation data are plotted out with corresponding coordinates in the x- and in the y-axis. Furthermore the digitized values of fluorescence intensities obtained with the scanning procedure are processed according to principles of automatic image-analysis procedures.

5-Methoxytryptamine↗
PubMedDate not supplied

Imaging features of adenomyosis.

This review focuses on non-invasive imaging techniques that have proven useful in diagnosing adenomyosis, including hysterosalpingography, transabdominal and endovaginal ultrasound, as well as magnetic resonance imaging. An understanding of the histopathological features of this disease is crucial when attempting to interpret the associated imaging findings. The muscular hyperplasia accompanying the heterotopic endometrial tissue actually produces the typical gross appearance of adenomyosis and corresponds to areas of decreased echogenicity or signal intensity on ultrasound and magnetic resonance imaging respectively. The heterotopic endometrial tissue also contributes to the imaging appearance of adenomyosis, and with the advent of high resolution imaging techniques, these changes are being detected with increasing frequency, including the presence of myometrial nodules, linear striation, poor definition and nodularity of the endo-myometrial junction, pseudowidening of the endometrium, and myometrial cysts or haemorrhagic foci. The purpose of this review is to (i) present the spectrum of imaging findings of adenomyosis, (ii) illustrate potential pitfalls in diagnosis and (iii) review the accuracy and role of currently available noninvasive imaging techniques.

Abdomen↗
PubMedDate not supplied

Fast spin echo STIR imaging.

OBJECTIVE: Our goal was to evaluate the image quality, contrast characteristics, and possible clinical utility of STIR images obtained using a fast SE (FSE) technique. MATERIALS AND METHODS: The signal and contrast characteristics of FSE STIR images were evaluated using a lipid/water phantom and normal volunteers. Based upon these results, optimal FSE STIR imaging parameters were chosen. Conventional STIR and FSE STIR images were then obtained (while maintaining an equal number of section locations between the two sequences) in a series of 14 patients with known musculoskeletal abnormalities. These images were compared side by side by two experienced MR radiologists for image quality and lesion detection. RESULTS: There were no statistically significant differences between the FSE STIR images and conventional STIR images in lesion detection, image quality, motion artifact, or final diagnosis. CONCLUSION: STIR imaging provides optimal contrast for detection of many pathologic abnormalities. This is especially true for musculoskeletal tumors and infection. The long imaging time and reduced number of sections obtainable with conventional SE (CSE) STIR sequences limit their routine use. Our results show that FSE STIR images of the musculoskeletal system can be obtained up to seven times more rapidly than CSE STIR images without compromising lesion detection or image quality.

Adipose Tissue↗