[Renal osteodystrophy: the spectrum of the x-ray symptoms in modern forms of kidney transplantation and long-term dialysis therapy]

Plain film radiography and microradioscopy represent standard imaging for diagnosis and grading of renal osteodystrophy. The aim of this retrospective study was to evaluate the effects of modern therapeutic regimens on skeletal abnormalities as diagnosed radiographically. 198 patients were investigated. X-ray findings of 38 patients from 1981-1983 (16-66 years, 40.1 +/- 13.4; 23 male, 15 female) were compared with those of 160 patients from 1991 (20-71 years, 48.4 +/- 12.5; 98 male, 62 female). We found significant differences in respect of the spectrum and the degree of skeletal abnormalities. The prevalence of phalangeal resorptions lowered from 87 to 50%, the prevalence of soft tissue calcification from 68 to 57%. Therefore, renal osteodystrophy is not as extensive as it was ten years ago, but it still continues to be an unavoidable complication of renal insufficiency.

Comparison of dual energy X-ray absorptiometry of the proximal femur with morphologic data

Measurements of bone mineral density (BMD) of the proximal femur (including femoral neck, Ward's triangle and trochanteric region) were compared with the Singh index grading in 40 normal subjects (20 male, 20 female) and in 116 patients (18 male, 98 female) referred for assessment of possible osteoporosis. Additionally, the BMD and the Singh index of 12 cadaver specimens (6 male, 6 female) of the proximal femur were compared with each other and with the histomorphology of the femoral necks of the specimens. Although there was a good correlation of Singh index with BMD in the group of male patients with suspected osteoporosis and in the series of bone specimens, there was a poor correlation in the group of female patients as well as in the normal controls and in the patient population as a whole. There was also poor correlation of Singh index values with histomorphologic data, whereas the BMD measurements correlated well with the amount of calcified bone found histologically in the femoral necks of the bone specimens. We conclude that the Singh index cannot be used to predict BMD of the proximal femur accurately.

Degenerative Achilles tendon disease: assessment by magnetic resonance and ultrasonography

As Magnetic Resonance (MR) imaging and Ultrasound (US) allow the evaluation of soft-tissue structures not previously possible with other imaging techniques, a clinical study has been undertaken to determine the value of these two modalities in the detection of lesions in the Achilles tendon (AT), other than acute total rupture. Seven healthy subjects and 28 symptomatic patients with Achillodynia and/or signs of thickening of the AT were investigated with MR and US; all results were compared with the clinical features. Surgical findings were available in 14 patients. The patients were divided into three groups; those with tendon thickening, incomplete and complete chronic ruptures. Thickening of the AT was easily detected with both methods. MR was superior in the detection of incomplete tendon rupture and in the evaluation of various stages of chronic degenerative changes. We conclude that only if US remains unclear, an additional MR study should be performed and together with the clinical diagnosis indication for surgery can be made more efficient.

[The screening of renal artery stenoses. The initial results with the value of color Doppler sonography]

The value of colour Doppler sonography in the diagnosis of renal artery stenosis has been studied retrospectively. 17 patients were examined (34 main renal arteries and 7 accessory renal arteries; ages 37 to 84 years; 7 males and 10 females). We studied 1) ability to study the main renal arteries, 2) visibility of accessory renal arteries and 3) the sensitivity and specificity of colour Doppler sonography for the diagnosis of renal artery stenosis. The results were compared with intraarterial angiography. Demonstration of the main renal arteries with colour Doppler sonography was possible in 23 of the 34 vessels. Not a single of the 7 accessory renal arteries was demonstrated by colour Doppler sonography. Of 8 angiographically demonstrated stenoses (more than 50% narrowing) 2 were missed by colour Doppler sonography. One stenosis was correctly diagnosed and 5 were incorrectly evaluated by sonography. 16 out of 18 angiographically normal main renal arteries were correctly evaluated by colour Doppler sonography but 2 showed a false positive finding. This results in a sensitivity of 17% and a specificity of 89% per kidney. Colour Doppler sonography cannot be recommended as a screening method for renal artery stenosis in view of its limited accuracy.

Renal transplant hemodynamics in children: prospective analysis of colour coded versus pulsed Doppler sonography

In 30 children with renal allografts the diagnostic validity of pulsed Doppler (PD) versus colour coded Doppler (CD) sonography was assessed prospectively. 46 PD examinations were performed calculating the resistive index (RI) in the segmental arteries in comparison to 46 CD scans, where renal blood flow throughout the grey-scale image was displayed. In addition, point-spectral analysis with calculation of the RI was also performed on the CD scans. The time for examination ranged from five to ten minutes for the PD and from three to five minutes for the CD study. Concordant findings for the PD and CD technique were generally obtained (normal blood flow pattern on PD-excellent visualization of renal blood flow on CD, reduced or reversed diastolic flow on PD-poor visualization of renal blood flow on CD). There was close correlation of the RI values obtained by the PD and CD scans. CD sonography facilitated point-spectral analysis in shortening the time for examination. The ability to visualize focal hemodynamic alterations provided a higher diagnostic accuracy in comparison to PD sonography.

[Pseudotumor of the orbit in pediatrics. Diagnostic imaging]

Orbital pseudotumor is an inflammatory lesion with increased orbital mass and a typical rapid onset. It is very uncommon in children. Diagnosis is difficult and there is no uniform procedure. Two patients with different forms of this entity are presented, and their clinical symptoms and CT and ultrasonographic features are discussed. We found the CT and US findings to be important for the differential diagnosis. Therefore, these diagnostic modalities should be applied immediately on the onset of typical clinical symptoms, because the condition can result in ophthalmoplegia and amaurosis if not treated at once.

[Velocity variance function: additional information in color-coded Doppler sonography of the carotids]

A new software, called the velocity variance programme, by which flow disturbances are additionally colour-coded, was systematically applied with colour Doppler sonography in 59 patients with stenotic atheromatous lesions of different grades in the carotid bifurcation. A direct comparison with and without using this programme was made. In group 1 (n = 23) with stenosis of the internal carotid artery of more than 50% it could be demonstrated that flow disturbances were maximally in the region immediately downstream of the stenosis and complete dissipation of these effects occurred within 8-10 vessel diameters downstream. Moreover, a direct correlation between the size of the region of disturbed flow and the irregularity of the stenotic plaque surface within the stenosis could be demonstrated. Distal to the stenosis there was an inverse relationship between the extension of disturbed flow and the length of the stenosis and a direct relationship to the grade of the stenosis and the irregularity of the plaque surface. In patient group 2 (n = 36) with less than 50% diameter reduction, a local flow disturbance near the atheromatous plaque was shown in 27 patients. In eighteen of these patients the region of disturbed flow could be revealed only by using the velocity variance programme. The importance of this non-invasive in-vivo visualisation of flow disturbances in the carotid bifurcation is discussed.

[Flow reversal in the carotid bifurcation. Detection using color-coded Doppler sonography]

Pulsatile blood flow within the normal carotid sinus involves at least two distinct components. Beside the laminar antegrade flow, there is a boundary layer separation zone in the posterolateral aspect with transient flow reversal. This flow reversal is well known from in vitro studies. It is now possible to document these flow velocity components using color-coded Doppler sonography. It is hypothesized that if flow separation is detected, this is indicative of a normal condition of the carotid bifurcation. When atherosclerosis develops, it involves preferentially the posterolateral bulb region, obliterating the normal configuration of the sinus with consequent loss of the flow separation. Therefore, loss of flow reversal should be indicative of atherosclerosis. We have studied this flow pattern retrospectively in 156 patients (312 arteries). In 4 patients no flow reversal could be detected although no atheromatous lesions could be found at the bifurcation, but in these cases there was no bulb formation in the common carotid artery or in the internal carotid artery. On the other hand, flow reversal was demonstrable in several pathological conditions within the carotid bifurcation. These included plaque formation after the bifurcation in 7 patients, internal carotid artery occlusion at the origin in 12, common carotid artery occlusion despite a patent bifurcation in 4, and marked dilatation of the lumen forming a pseudobulb following disocclusion of the carotid artery in 11 patients.

Renal osteodystrophy. Radiological diagnosis compared with a new radioimmunoassay method of parathyroid hormone

The parathyroid hormone concentration in the blood measured by the 'two-site radioimmunoassay', which is specific for the biologically active parathyroid molecule (parathyrine), was compared with the radiological manifestations of secondary hyperparathyroidism (HPT) on magnification radiographs of the phalanges in patients undergoing maintenance hemodialysis and in patients with renal allografts. Sensitivity of radiology for the diagnosis of HPT proved to be high (88%), whereas specificity was low (30%). Statistical analysis showed that there was a good correlation between the parathyrine levels and the intensity of radiological changes in the phalanges in patients with renal allografts (coefficient of Krueger-Spearman = 0.65). In patients undergoing hemodialysis the correlation between laboratory parameters and radiological changes was poor.

[Sonographic localization of the kidneys for the purpose of radiation treatment of the abdomen: how accurate is this method?]

In 31 patients, the kidneys were located with ultrasonography before urography was carried out. The projection of the medial, lateral, cranial and caudal margins of the kidney were marked on the patient's back with a pellet. On X-ray film, the mean distance between the pellet and margin of the kidney varied from 0.12 to 1.13 cm; nevertheless the standard deviations were high (up to 2.63 cm). In 11 patients, more than one-third of the kidney was located outside the sonographically determined borders; on the left side this happened in 10 patients. We conclude that sonographical localization of the kidneys for protection during irradiation of the abdomen should only be used when other localization procedures cannot be carried out.

Duplex sonography of normal renal allografts

Thirty-five patients with normal renal allografts as well as 10 healthy volunteers with normal native kidneys were examined by duplex sonography. Blood flow measurements were performed in the main renal artery as well as in segmental, interlobar and arcuate arteries. In both groups the normal range of variation in blood flow was defined by using the resistive index (RI). Doppler wave forms and RI of main renal arteries were both similar to those of their branches. In renal allografts as well as in native kidneys the blood flow pattern showed a rapid up-slope in systole followed by a gradual down-slope in early diastole, with a persistent flow throughout diastole. In addition, there was no significant difference in the RI between allografted and native kidneys. The interobserver variability was less than 10 per cent. The mean RI was 0.68 using all data points. Vascular rejection in 11 patients could be discriminated significantly (p less than 0.001). Duplex sonography is useful in evaluating renal blood flow. This simple and non-invasive technique seems to be useful in long-term follow-up of renal allograft recipients.

[Color-coded Doppler sonography of kidney transplants]

A prospective study was carried out in 81 patients to compare the ability of colour coded Doppler sonography (angiodynography) and Tc bolus examination for demonstrating renal blood supply. In patients with normal transplant function both methods performed equally well. In anuric patients angiodynography was superior to the Tc bolus examination: In three cases angiodynography was able to provide important additional information such as absence of blood flow in peripheral intrarenal vessels or missing blood supply of a transplant pole. Angiodynography seems to be able to replace the Tc bolus examination; this statement excludes very obese patients until low-frequency probes for angiodynography will be available.

[Computerized tomography analysis of cement-free total hip endoprostheses]

16 patients with total hip endoprosthesis were investigated by high resolution computed tomography (CT) to analyse possible advantages of CT over conventional radiography. The quality of the examinations was good only in pure titanium systems: examinations of chromium-molybdenum alloys were severely deteriorated by strike artifacts. Positioning of implants is well defined in radiographs; CT provides better visualisation of the relation between implant and cortical bone. Evaluation of the contact of the shaft to the femoral corticalis is difficult in radiographs but facilitated in axial scans. Determination of relevance of CT analysis of total hip endoprosthesis remains subject to a future long-term follow-up study.

[Sonography of the Achilles tendon and its bursa]

Pain and disturbed function in the sole of the foot leads to damage of the tendo Achilles and to abnormalities in its vicinity. They are frequent consequences of some sporting activities (jogging). Differentiation between bursitis, fat necrosis, degenerative changes in tendons and their rupture and from abnormalities of the ankle joint is important for treatment. In the symptomatic patients whom we examined, the bursa was involved in 72.9% and lesions of the tendo Achilles were found in 62.1%.

[Diagnosis of varices in liver cirrhosis: duplex ultrasound versus gastroscopy]

This study assesses the usefulness of duplex sonography in the diagnosis of oesophageal varices. 32 patients with liver cirrhosis were studied by endoscopy and duplex sonography. There was an excellent correlation in the case of the medium-sized and large-sized varices. Only small varices could not be detected by duplex sonography. On the other hand, 3 large-sized paraoesophageal varices, which were not identified by endoscopy, were easily seen by duplex sonography. The sensitivity of duplex sonography was between 0.8 and 0.9, the accuracy between 0.93 and 0.96.

[Intolerance reaction following glucagon administration in a double-contrast study]

Whereas intolerance reactions against contrast media are a well-known hazard during radiologic procedures, intolerance reactions to other preparations used in radiology are rare. Glucagon, frequently used to induce gastrointestinal hypotonia, is said to have almost no side-effects. A case of anaphylactic reaction during double-contrast upper gastrointestinal examination is reported. Pseudoallergic reaction to propylparaben, a preservative agent in glucagon, is suspected. IgE-antibodies to glucagon could not be detected by RAST.

[Radiation dose to the sternum during mammography (author's transl)]

Previous measurements of radiation to the sternum during mammography in the living subject have shown relatively high doses to the surface of this region. It was therefore decided to carry out measurements on a sternal phantom. The aim of the investigation was to obtain information on the dose to the sternal marrow cavity. Measurements were carried out with a thermoluminescent dosimeter. It was shown that the mean dose to the marrow amounts to about 24% of surface dose, depending on the angle of incidence. This dose cannot be totally ignored. Protection of the sternum is therefore recommended. This is easily accomplished and takes little time or effort.