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C F Hess

Publications and source records attributed to C F Hess.

At least 19 recordsLinked to original sources
PubMed1989

Diagnosis of liver cirrhosis with US: receiver-operating characteristic analysis of multidimensional caudate lobe indexes.

To assess the utility of changes in the volume of the caudate lobe in the sonographic diagnosis of liver cirrhosis, the authors studied 58 patients with histologically proved cirrhosis, 18 patients with fatty liver, 28 patients with liver metastases, seven patients with lymphomatous liver involvement, and 75 healthy individuals. The longitudinal (CL), transverse (CT), and anteroposterior (CAP) diameters of the caudate lobe and the transverse diameter of the right lobe (RL) were measured, and one-, two-, and three-dimensional caudate lobe indexes and ratios were calculated. The analysis of the diagnostic performance of these criteria, compared by means of receiver-operating characteristic curves, revealed that the ratio of the three-dimensional caudate index (CI3) to the right lobe diameter (CI3/RL = [CL X CT X CAP]/RL) was superior to all other calculated criteria. At a specificity of 95%, the sensitivity of CI3/RL was 94.7%, compared with 73.3% for CT/RL. No significant differences were found between the control group and patients with fatty liver, metastases, or lymphomatous involvement. The study suggests that CI3/RL is the most reliable quantitative criterion for the US diagnosis of liver cirrhosis.

Fatty Liver↗
PubMed1989

Diagnosis of fistulae and sinus tracts in patients with Crohn disease: value of MR imaging.

To investigate the potential of MR imaging in the evaluation of sinus tracts or fistulae associated with Crohn disease, 17 patients with pelvic or abdominal fistulae or sinus tracts underwent MR imaging with multislice spin-echo techniques, 500/15 and 1600/22,80 (TR/TE). The presence of fistulae and/or sinus tracts was confirmed by contrast-enhanced CT (n = 17) and/or sonography (n = 8), sinography (n = 6), or barium studies (n = 4). In all but three cases the fistulae and extramucosal inflammatory abnormalities were shown by MR. T1-weighted images provided excellent delineation of the extension of the fistulae relative to sphincters and adjacent hollow viscera and showed inflammatory changes in fat planes. T2-weighted images showed fluid collections within the fistulae, localized fluid collections in extraintestinal tissues, and inflammatory changes within muscles. The supralevator and infralevator compartments were well defined on coronal images. Thus, the perirectal spread of fistulae and sinus tracts with respect to the levator ani could be demonstrated in all cases. Our results suggest that MR imaging is useful for the demonstration and evaluation of pelvic and abdominal sinus tracts or fistulae associated with Crohn disease.

Abscess↗
PubMed1988

[Renal involvement in malignant lymphoma: significance of imaging technics for determining spread].

Large autopsy series show an incidence of 33 to 62% of renal involvement in all patients with malignant lymphoma; at the time of diagnosis, this is found only very rarely. The present paper describes three patients with renal involvement at the time of diagnosis. The value of sonography, CT and angiography in detecting renal involvement and its clinical significance in the management of malignant lymphoma is discussed.

Adult↗
PubMed1988

[Parameter-weighted MR images and their optimization: theory and example of images for the flash sequence compared to the spin-echo sequence].

In this paper the signal intensity and parameter-weighting zones of spin echo and gradient echo sequences (FLASH) have been analysed. Using information available in the literature, with additional analytical and numerical techniques, it is possible to determine parameters which maximise tissue contrast for T1, T2 and proton-weighted images. The technique is equally applicable to spin echo and FLASH sequences. The advantages of optimised gradient echo sequences compared with spin echo sequences with respect to its signal to noise ratio for short repetition times are analysed quantitatively. T2-weighted images can be generated as rapid as T1-weighted images, using the FLASH sequences when using a small angle of spin and relatively long echo. Illustrations are shown to demonstrate the numerical results (field strength 1.5 tesla). This is followed by a discussion of possible opposing effects.

Humans↗
PubMed1988

[Reproducibility of the sonographic determination of the size of intra-abdominal space-occupying lesions].

The reproducibility of sonographic measurements was checked using 255 measurements on 57 intra-abdominal masses. It was shown that differences of measurements carried out independently by two observers increased in a linear manner with tumour diameter. Relative differences in measurement averaged 10%, but in 5% of cases they reached 30%. Somewhat better results were obtained with small tumours and for measurements lying strictly in the axis of the body. The significance of these findings in clinical practice, particularly for tumour follow-up, is discussed.

Abdominal Neoplasms↗
PubMed1988

Small arteries in peripheral lymph nodes: a specific US sign of lymphomatous involvement.

Fifty-seven patients with palpably enlarged peripheral lymph nodes underwent detailed ultrasonographic (US) examination with a 5.0-MHz and a 7.5-MHz probe. In 32 of 36 patients with malignant lymphoma (12 with Hodgkin disease, 24 with non-Hodgkin lymphoma) US showed a hypoechoic mass with a centrally located tubular structure. Pathologic examination showed that this structure correlated with small intact arterial vessels encased by confluent lymphomatous masses. This sonographic finding was not seen in patients with carcinomatous metastatic lesions to the lymph nodes (nine patients) or benign lymphadenitis (12 patients). The detection with US of small arteries within enlarged lymph nodes may indicate nodal infiltration by malignant lymphoma.

Arteries↗
PubMed1987

[1st results of the diagnosis of focal liver and spleen lesions using gradient echo sequences].

15 healthy subjects and 39 patients with focal liver and spleen lesions were examined via MR tomography at 1.5 tesla. Gradient field echos at small angle excitation (less than 90 degrees) were employed. The imaging time per layer was 10 seconds so that rapid imaging could be carried out at respiratory standstill. This enabled visualisation of liver and spleen without interference by breathing artifacts and with accurate localisation. Focal lesions can be imaged best at low flip-angle pulses (liver) or low to medium-angle pulses (spleen). The primary liver cell carcinoma is visualised as an inhomogeneous structure with similar signal intensity as the surrounding tissue. All other examined liver lesions (metastases, haemangiomas, lymphatic infiltrates, echinococcus cysts, FNH, gummae) showed greater signal intensity than the remaining organ at small angle excitation. Furthermore, contrast reversals were seen at medium-angle pulses. Contrariwise, with the exception of the light-coloured spleen infarcts, spleen lesions (lymphatic infiltrate, Boeck's disease or sarcoidosis) appeared darker at all excitation angles than the surrounding tissue.

Humans↗
PubMed1987

[Focal changes in the spleen. Ultrasonic morphological characteristics and their clinical significance].

Focal changes in the spleen were rare findings in a large clinical material (less than 1% of cases). In a prospective study, which included 580 patients, lesions in the spleen were found in 40. Four focal lesions were due to infiltrates from non-Hodgkin's lymphoma. Twenty-one lesions with low echoes consisted of twelve infiltrates from Hodgkin's disease (six patients) or non-Hodgkin's lymphoma (six patients), five were due to fresh splenic infarcts and one each to an abscess, a metastasis from a carcinoma of the stomach, sarcoid and a haemorrhage. In only three of ten highly echogenic foci was a diagnosis possible (one leukaemic infiltrate and two scars following splenic infarcts). The significance of the sonographic demonstration of focal splenic lesions for diagnosis and treatment is discussed. The advantages of a sector scanner for evaluation of the spleen and splenic size are mentioned.

Hodgkin Disease↗
PubMed1987

[The internal echo pattern of the normal pancreas. An assessment of the aging process and body weight dependence by sonographic gray-scale analysis].

Sonography of the pancreas was evaluated quantitatively in 94 normal subjects. The grey-scale values in the head and body of the pancreas were measured and compared with those of retroperitoneal fat. The echogenicity of the pancreas and the contrast between pancreas and fat were correlated with the age and weight of the subjects. Semi-quantitative studies revealed a positive correlation between echogenicity and age (r = 0.505); this can be confirmed to a high degree of statistical significance by quantitative analysis of pancreatic grey-scale values (r = 0.55 for the head and 0.71 for the body). Further improved correlation with age is obtained by computing the sonographic contrast between the pancreas and the retroperitoneal fat (r = 0.66 for the head and 0.77 for the body of the pancreas). It is concluded that determination of the grey-scale value can provide additional information particularly if one uses retroperitoneal fat as a reference tissue.

Adipose Tissue↗
PubMed1986

[Imaging of prostatic cancer by 1.5 Tesla nuclear resonance tomography].

Twenty-two patients with histologically confirmed carcinomas of the prostate were examined by nuclear magnetic resonance, using a 1.5 Tesla magnet (stage T1: one patient, T2: eight patients, T3: six patients, T4: seven patients). In 19 out of the 21 patients in stages T2 to T4, the tumour showed a specific signal intensity. In 12 cases, the tumour signal was more intense than from a normal prostate when using medium repetition and echo delay times; in 19 cases, multi-echo sequences with increasing echo delay time (30 to 240 ms) and long repetition times (usually 1600 ms) showed less reduction in signal intensity than surrounding structures (except urine). Unlike computed tomography, 1.5 Tesla MR is able to demonstrate carcinomas confined to the prostate. Demonstration of infiltration is possible with MR with great accuracy because of the ability to obtain images in three planes and because of the accurate rendering of soft tissue detail. In particular, MR differentiates between stages T2 and T3 more clearly than does CT. The best demonstration of anatomical structures in the true pelvis is achieved with a repetition time of 800 ms and an echo delay time of 30 ms, the best demonstration of tumour with corresponding 1600 ms and 120 ms. The effect of catheters in the bladder, or previous transurethral resection on the MR images is discussed.

Aged↗
PubMed1986

[Subjective evaluation and quantitative gray-scale analysis in the sonographic diagnosis of diffuse changes in the liver parenchyma].

Two investigators were asked to evaluate independently the echogenicity, coarsening and inhomogeneity of the hepatic echo pattern in a semi-quantitative manner; they had no knowledge of the diagnosis and used the same apparatus. The three subjective criteria were largely independent from the observer. Approximately three-quarters of all patients with slightly increased echogenicity showed a subjective appearance of coarsening; the impression of inhomogeneity increased significantly with increasing echogenicity. This is of importance in the sonographic evaluation of cirrhosis of the liver and in the diagnosis of diffuse liver metastases in a fatty liver. Grey scale analysis within a region of interest showed satisfactory correlation between the measured mean grey scale and echogenicity. Standard deviation within the grey scale was redundant, and there was no correlation between the other subjective characteristics and quantitatively measurable values.

Fatty Liver↗
PubMed1985

[Importance of thyroid hormone determination in the diagnosis of hyperthyroidism--significant improvement in medical assessment using decision theory results].

A "schematic" classification of the results of serum thyroid hormone measurements on the basis of mathematical decision theory proves to be superior to the physicians' conventional evaluation. That has been shown by comparison with the evaluations made by three experienced doctors. When using no control regions (but the results of serum T4, FT4 and T3 simultaneously) the physicians' rates of misrecognition (0-2% false positives, 20-27% false negatives) are only a little lower than when classifying schematically on the basis of only one thyroid hormone. The construction of a suitable control region, however, results when T3 alone is used, in only 7% false negative and 0% false positive results, while these rates remain nearly unchanged for the physicians' evaluations. The optimum application of mathematical decision theory is only possible with the knowledge of the statistical distributions of the thyroid hormone data, both for a representative collective of normals and that of patients with proven hyperthyroidism. Thus, quantitative criteria for the effectiveness of each set of thyroid hormones can be constructed and a multivariate analysis can be performed, in our example - when applying suitable control regions - even with vanishing rates of misrecognition.

Decision Theory↗
PubMedDate not supplied

MR imaging of urinary bladder neoplasms.

The diagnostic potential of magnetic resonance (MR) imaging at 1.5 T for assessment and staging of urinary bladder tumors was investigated in 10 patients with malignant urinary bladder tumors. All patients underwent complete pathologic staging. The appearance of the urinary bladder tumors and the ability to stage them by means of MR imaging was evaluated morphologically and compared with results obtained with pathologic examination. Magnetic resonance imaging permitted tumor localization in all patients. In nine patients the tumor stage was accurately determined by MR imaging. The smallest tumor detected by MR imaging was 1.5 cm. Both transverse and sagittal imaging planes were found to be essential for accurate assessment of tumor extension. Signal intensity data obtained from both dual and multi spin echo sequences showed that tumor display and depth of infiltration was best seen with a repetition time (TR) of 2,000 ms and an echo time (TE) of 90 ms. Accurate evaluation of perivesical tumor infiltration required a sequence with a TR 800 ms and a TE 30 ms. Data presented here further support the role of MR in staging urinary bladder neoplasms.

Aged↗
PubMedDate not supplied

Focal lesions of the spleen: preliminary results with fast MR imaging at 1.5 T.

Sixteen patients with splenic lymphoma and six with nonlymphomatous splenic lesions underwent magnetic resonance (MR) imaging, ultrasound (US), and dynamic CT. All patients were studied at 1.5 T with gradient echo sequences using a repetition time of 80 ms, echo time of 16 ms, and two pulse angles of 30 and 60 degrees. In 14 patients with lymphomatous lesions fast MR showed circumscribed areas of low signal intensity at both pulse angles. The lesion-to-spleen contrast was better on images acquired with a pulse angle of 30 degrees. For fast MR with pulse angles of 30 degrees, the mean lesion-to-spleen contrast was similar to US and contrast-enhanced CT. However, with fast MR the contrast showed a lower variability and was considerably better than with unenhanced CT. In one patient fast MR showed splenic involvement that was missed on both CT and US. The signal characteristics of lymphomatous, leukemic, and sarcoid involvement and of healed infarcts were similar and indistinguishable on fast MR images. Recent splenic infarctions (three cases) were, however, distinctly different, characterized by regions of high signal intensity at both pulse angles. The results of this preliminary study suggest that fast MR imaging is a promising diagnostic tool for the assessment of splenic disorders.

Diagnosis, Differential↗
PubMedDate not supplied

MR characteristics of prostatic carcinoma and benign prostatic hyperplasia at 1.5 T.

Sixty-one patients with histologically proven disorders of the prostate [prostatic carcinoma (PC), 41; benign prostatic hyperplasia (BPH), 9; PC and BPH, 11] underwent magnetic resonance imaging at 1.5 T. Using single [spin echo (SE) 400/30] and dual (SE 1,600/30, 90) SE sequences, multislice contiguous scans were obtained in transverse, sagittal, and coronal planes through the prostate. In 27 patients (PC 14, BPH 6, PC and BPH 7) multiecho sequences with eight echoes (SE 1,600/30, 60, 90, 120, 150, 180, 210, 240) were acquired and T2 images were calculated in the planes with best depiction of circumscribed prostatic pathology. In these patients the Bhattacharyya coefficient, a quantitative criterion for the discrimination between normal and pathological tissue, derived by means of mathematical decision theory, was applied. This analysis showed the best discrimination between PC and normal prostate with echo time (TE) 90 and 120 ms [error rate (ER) for confusing these tissues 20-30%]. There was no significant difference between the signal intensities of PC and BPH at any parameter setting, but PC could be discriminated from the compressed peripheral glandular regions that often accompany BPH [minimal ER (20-30%) at TE 90 and 120 ms]. This distinction is of clinical value, since PC usually arises in the periphery of the prostate. Calculated T2 images did not show advantages for the detection of PC.

Adenocarcinoma↗