Einflußnahme von Rontgenkontrastmitteln auf Schilddrüsenhormonparameter als Soforteffekt

Untersuchungen einer Reihe von Funktionsparametern der Schilddru-senhormone direkt im Anschluß nach Gabe verschiedener Kontrastmittel ergaben insbesondere nach Applikation von Biliscopin®, das als gallegängiges Kontrastmittel eine starke Eiweißbindung aufweist, signifikante Anstiege der freien Schilddrüsenhor-monfraktionen, eine signifikante Zunahme der Bindungskapazität der spezifischen Transportproteine und eine Abnahme der Gesamtschilddrüsen-hormonkonzentration. Die letztgenannte Änderung dürfte Folge eines Dilutionseffektes sein, während die Anstiege des FT3 und des FT4 im Serum moglicherweise durch eine Änderung der Bindungsaffinität der Zell-membranrezeptoren fur Schilddrüsen-hormone erklärt werden können. Daher sollte Blut zur Bestimmung von thyreoidalen Funktionsparametern weder in der Frühphase, innerhalb von einer Stunde, noch in der Spät-phase, innerhalb von 10 Tagen nach Gabe von Kontrastmittel entnommen werden, da andernfalls Fehlinterpretationen der erhaltenen Ergebnisse zu befiirchten sind.

Angiomyolipoma of the Kidney

In six patients with angiomyolipoma of the kidney, five showed a typical pattern in T1, proton and T2 weighted images, with magnetic resonance imaging (MRI). Angiomyolipoma is recognized by its characteristic fatty tissue components, which result in high signal intensity in T1 and proton weighted images and a low signal in T2 weighted images. Five of the patients were also examined with ultrasonography (US); in four of these, the tumor could be recognized by its echodense pattern. Computed tomography (CT) was slightly less sensitive; three out of six examinations failed to produce a definite diagnosis. Instead of the typical low attenuation values of fat, Hounsfield units similar to either muscle or kidney tissue were observed in these 3 cases. In conclusion, the specific diagnosis of angiomyolipoma depends on the amount of fatty tissue present at MRI, CT, and sonography.

Spondylolysis and isthmic spondylolisthesis: impact of vertebral hypoplasia on the use of the Meyerding classification

BACKGROUND

Spondylolysis and isthmic spondylolisthesis are common multifactorial disorders. The extent of slipping of the spondylolytic vertebra is considered a major predicator for prognosis and further follow-up. Vertebral hypoplasia is a common finding associated with spondylolysis. The purpose of this study is to evaluate the incidence of hypoplastic vertebral bodies in patients with spondylolysis and in the general population and to analyse the impact of the findings on the measurement and grading of spondylolisthesis.

METHODS

140 patients with 141 levels of spondylolysis identified by MRI were included in this study. The slippage of the spondylolytic vertebral body and the size in the midline sagittal image were measured and correlated. In addition, a randomised control group was evaluated to test the hypothesis that shortened, hypoplastic vertebral bodies can also be found in the general population.

RESULTS

Shortened, hypoplastic vertebrae were found in 50 patients with spondylolysis and none was found in the control group. These shortened vertebrae mimicked spondylolisthesis and in 19 patients the slippage equalled the shortening, thus mimicking spondylolisthesis, although only spondylolysis was present.

CONCLUSION

Sagittal shortening of the spondylolytic vertebra is common and may mimic spondylolisthesis. In order to define and measure spondylolisthesis the shortening of the spondylolytic vertebra has to be taken into account.

Features of positional magnetic resonance imaging in tethered cord syndrome

PURPOSE

Tethered cord syndrome (TCS) is a clinical entity in which symptoms are induced through excessive tension on the spinal cord. The radiological method of choice to confirm TCS is magnetic resonance imaging (MRI), however limitations exist especially in patients with no underlying spinal dysraphism.

MATERIALS AND METHODS

The positional MRI features of TCS in a series of four patients with suspected or proven TCS are described, especially with respect to contact of the myelon or the cauda equina with the dorsal elements of the lumbar spinal canal. The findings are correlated with the lordosis angle of the lumbar spine.

RESULTS

In flexion contact of the myelon or the cauda equina with the dorsal elements of the lumbar spinal canal is reduced due to a straightening of the lumbar spine. With increasing lordosis of the lumbar spine, the degree of contact increases and detection of TCS is more difficult. The site of tethering could be identified in all four patients in flexion.

CONCLUSION

Positional MRI can be useful to confirm or rule out TCS and helpful to identify the site of tethering. The value of positional MRI is limited to patients who are able to fully flex the lumbar spine and in patients without spinal canal stenosis and spondylolisthesis.

Spondylolisthesis and posterior instability

We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.

Direct evidence for the incorporation of univalent indium into high-silica zeolite, H-ZSM-5, by thermal auto-reductive solid-state ion exchange

In mechanical mixtures of H-ZSM-5 and In2O3 thermal auto-reductive solid-state ion exchange (AR-SSIE) was found to proceed upon treatment in high vacuum at 840 K resulting in the incorporation of In+ ions into, and in an increase of the thermal stability of, the zeolitic component.

[Syphilis and AIDS: a historical comparison]

The present work displays the analogies and differences among syphilis and AIDS concerning appearance, evolution, symptoms, treatment, prophylaxis, spreading, as well as their names' origin. A comparative analysis among both diseases in terms of causes, clinical evolution and therapeutic essays is established. Venezuelan health institutions' effectiveness in fighting these diseases is evaluated.

[Cine-MRT in the functional and morphological diagnosis of the heart after a myocardial infarct/ A comparison with angiocardiography, 2-dimensional echocardiography, intracardiac scintigraphy and enzymatic infarct size estimation]

PURPOSE

The aim of the study was to test the reliability of cine magnetic resonance imaging (cine-MRI) on the infarction heart with its altered geometry.

MATERIAL AND METHODS

61 patients (17 women, 44 men, 36-83 years, 32 with anterior, 29 with posterior wall infarction) received Cine-MRI in the true long and short axis of the heart and two-dimensional echocardiography one and 4 weeks post infarction. Two-level angiocardiography (ACG) and radionuclide ventriculography (RNV) were performed 4 weeks p.i. The size of myocardial infarction was determined enzymatically with the CK integral method. Left ventricular volume indices (EDVI, ESVI, SVI), ejection fraction (EF) and infarction weight (IW) were compared.

RESULTS

Excellent correlations existed between cine-MRI in the long and short axis for the volume indices and EF. Between cine-MRI in the short axis and ACG all correlations were excellent as well. They were significantly less satisfactory between cine-MRI and 2DE due to the inhomogeneity of echo quality. Cine-MRI and RNV produced similar EF results (r = 0.884), and a comparison of IW in cine-MRI and CK integral method also showed a good correspondence (r = 0.967).

CONCLUSION

Cine-MRI is a reliable method for the morphological and functional examination of post-myocardial infarction.

31-P MR spectroscopy and MRI of a testicular non-Hodgkin lymphoma recurrence to monitor response to irradiation. A case report

PURPOSE

To monitor the metabolic changes during the radiation treatment of a recurrence of a high malignant non-Hodgkin lymphoma (NHL) of the left testis.

PATIENTS AND METHODS

A 76-year old patients who presented a diffuse centroblastic high malignant NHL recurrence in the left scrotal sac was examined with 31-P magnetic resonance spectroscopy (MRS) and proton magnetic resonance imaging (MRI) before, during and after megavoltage radiotherapy to a total dose of 56 Gy.

RESULTS

The 31-P MRS spectrum of the tumor showed before starting irradiation, intensive phosphomonoester (PME) and phosphodiester (PDE) signals that overlapped the inorganic phosphate (Pi) signal. After 26 Gy irradiation, the Pi peak appeared and revealed an intratumoral pH of 7.08 very close to that in the normal testis (pH of 7.02). After 56 Gy the tumor disappeared and a complete remission was achieved.

CONCLUSIONS

1. 31-P MRS is sensitive to the changes in the tumor metabolic activity after irradiation with a dose of 26 Gy. 2. Pi and PME peaks could be good pathological markers in the steady-state response to irradiation. 3. MRI could confirm the radiation induced tumor regression and the achieved clinical complete remission.

31-P mr spectroscopy of a leg lymphangiosarcoma

In a 64 year old man with a large, low grade lymphangiosarcoma of the right thigh, we correlated the results of in vivo 31-P-magnetic resonance spectroscopy (MRS), proton magnetic resonance imaging (MRI), and digital subtraction (DSA) with the pathologic specimen and histology. The 31-P MRS spectra of the tumor showed well-resolved peaks as follows: intense PCr (phosphocreatine), PDE (phosphodiester) and Pi (inorganic phosphate), and low PME (phosphomonoester). The Pi peak revealed an intratumor pH of 6.96 compared with 7.16 of normal skeletal muscle. The lower PME signal was consistent with low histopathologic mitotic activity of the tumor.

[MRI characteristics of the Sneddon syndrome]

The report describes the MRI findings in a female patient with an established long course of a Sneddon's syndrome. Multiple ischaemic cerebral infarcts of a mainly macroangiopathic pattern are typical. In the beginning the corresponding clinical deficiencies often show a considerable regression.

Altered muscle metabolism in pustular psoriasis (Zumbusch type): demonstration by 31P magnetic resonance spectroscopy

We report a patient with pustular psoriasis (Zumbusch type) with diffuse muscle pain. Evaluation of skeletal muscle metabolism during rest, graded levels of exercise and recovery was performed using 31phosphor magnetic resonance spectroscopy (31P MRS). Our results underline the systemic character of severe pustular psoriasis. The clinical improvement after drug therapy (prednisolone and etretinate) correlated well with the measurable changes in vivo of several metabolites and indices important in muscle contraction, such as phosphocreatine (PCr), inorganic phosphate (P(i)), intramuscular pH and the phosphorylation potential (PCr/Pi). Abnormal accumulation of sugar phosphates (phosphomonoester) as well as their slow resolution during recovery reflect profound alteration of metabolism in the sense of block in glycolysis. Our results show that 31P MRS is well suited to identify and measure subtle changes in the muscle metabolism occurring in pustular psoriasis.

Magnetic resonance imaging and computer tomography of acute spinal cord trauma

Spinal cord lesions are not detectable on roentgenograms and computed tomography (CT) scans. Magnetic resonance images (MRIs) are able to make soft-tissue lesions visible. Interpretations of MRIs, CT scans, and roentgenograms were compared in 25 patients and three postmortem specimens with spinal cord injuries. In 14 patients and one specimen with normal roentgenograms and CT scans, the MRI demonstrated ten soft-tissue injuries as minimal displacement of the vertebral bodies or as a high signal intensity in the disc space, indicating a hematoma. Seven of the ten patients demonstrating soft-tissue injuries also had an intramedullary lesion, while in five of the 15 patients with normal CT scans, only a medullary lesion was present on MRI. In 11 patients and two postmortem specimens, fractures were seen on roentgenograms and CT scans. In these patients, the CT was superior to the MRI in detecting small bony fragments, but the medullary lesions were visible only on the MRIs. An intramedullary low signal intensity corresponded to macroscopically visible hemorrhages in the three postmortem specimens. The MRI provided important information in patients with neurologic deficits. No obvious pathologic changes were evident on the roentgenograms and CT scans. The MRI also demonstrated intramedullary and extramedullary soft-tissue lesions and was useful in establishing a diagnosis and in choosing appropriate therapy. CT, on the other hand, was superior in detecting small bony fragments and fracture lines.

[A combination of generalized neurofibromatosis (Recklinghausen disease) and agenesis of the corpus callosum]

Whereas generalised neurofibromatosis is a relatively frequent disease its combined occurrence in conjunction with agenesia of the corpus callosum is extremely rare and probably a casual coincidence.

[Generalized brain edema and cerebral infarct in ergotamine abuse: imaging by computerized tomography, magnetic resonance tomography and angiography]

Abuse of ergotamine can release a generalised brain edema and brain infarctions. This can be visualized by CT, MR and angiography. The reason, however, can only be found in the patients history.

[Possibilities of phosphorus 31 spectroscopy in assessing the therapeutic effects on cellular energy metabolism of the myocardium]

We present a general review of the literature concerning the role of the 31 P spectroscopy in studying the metabolic effects of drugs like verapamil, chlorpromazin, propranolol, acebutolol, 2-mercaptopropionylglycine, insulin, 2-deoxyglucose, cardioplegic solutions, as well as perfluorocarbon solutions on the energy status of the ischemic myocardium. Using 31 P spectroscopy several important results have been found concerning the changes of the concentration of the high energy phosphates and of the intracellular pH during myocardial ischemia. It is now possible to gain interesting insights into the metabolic effects of different drugs. By using these drugs, changes in the high energy phosphates, as PCr and ATP were attenuated during the myocardial ischemia. A better recovery of the PCr and ATP contents during reperfusion was noted. The myocardial pH changes during ischemia are attenuated compared to controls. A good correlation between the preservation of the high energy phosphates and myocardial pH and the recovery of the ventricular function was described. An in vivo documentation of the mitochondrial oxidative phosphorylation is now possible. A short overview is presented about the phosphorylation potential and its prognostic value for various cardiac diseases. The 31 P spectroscopy successfully shifted the research interest towards biochemical processes at the cellular level in the diagnosis and therapy monitoring. It extends our knowledge on the pathophysiology of the myocardium.

[Quantifying mineralization processes in post-traumatic algodystrophy using computerized tomography densitometry]

Computed tomography examinations have been made in 12 patients with posttraumatic algodystrophy. Significant differences of sides were found to be a measure of demineralisation by CT densitometry. 7 patients could be repeatedly examined during up to 60 weeks after the trauma. CT-integrated densitometry enables to quantify the process of de- and remineralisation and to objectify the disease according to the spongiosa bone. It seems to be possible to value the process of mineralisation by this method.

[The value of magnetic resonance tomography using gadolinium-DTPA in the diagnosis of the post-lumbar disk surgery syndrome]

Our results have shown that MR tomography - especially if gadolinium-DTPA is used as a contrast medium - is an excellent method to differentiate between the various possible causes of the post-discotomy syndrome. In particular, it is definitely possible to differentiate between a relapsed hernia of an intervertebral disc and a postoperative development of cicatricial tissue which is practically inevitable. This differentiation is of vital importance to the clinician, because a second operation should be performed only in case of a relapse, whereas cicatricial tissue is best left alone, because no matter how carefully the operation is performed with preparation of the neural structures, even more extensive cicatricial plates are bound to develop. Instability of the vertebral column in the operated disc segment, or other causes of complaints, can be identified via MR equally well if not better than by other means. Hence, the method should be the method of choice in postdiscotomy syndrome, since it facilitates the difficult choice between conservative therapy and reoperation.

[The present status of the radiologic diagnosis of acute pulmonary failure]

Acute pulmonary failure is a very serious cause of respiratory failure and can occur in association with a multitude of disease. Radiological diagnosis occupies a central position in intensive-care monitoring. X-ray film of the thorax is performed not only for detecting any complications, but mainly for noninvasive and semiquantitative determination of the extravascular pulmonary fluid and hence of the fluid balance, although it is imperative to take into account any influence that associated disease and therapy measures. Other methods such as MR or methods of nuclear medicine have not acquired substantial importance in respect of diagnosing and monitoring acute pulmonary failure.

[Magnetic resonance tomography studies with contrast media in post-discotomy syndrome]

The syndrome encompassing failed back-surgery is a relatively uniform combination of complaints caused by a variety of pathological changes in the lumbar spine, alone or in various combinations. The MRI's capability of detecting these factors is described. MRI can detect recurrent disc herniations and separate them from intradural and/or extradural scar formation. With further experience, MRI might also be able to assess instability of the lumbar spine motion segments. MRI is not very helpful in detecting neural lesions or facette syndromes. For this kind of pathology, advances in diagnosis will depend on the further improvement of neuro- and electrophysiological tests. The same applies to the diagnosis of cases of spinal stenosis. The size of the spinal canal can be measured by MRI as well as by other modalities. These results just point out the risk of disease - not the disease itself.

Angiomyolipoma of the kidney. Comparison between magnetic resonance imaging, computed tomography, and ultrasonography for diagnosis

In six patients with angiomyolipoma of the kidney, five showed a typical pattern in T1, proton and T2 weighted images, with magnetic resonance imaging (MRI). Angiomyolipoma is recognized by its characteristic fatty tissue components, which result in high signal intensity in T1 and proton weighted images and a low signal in T2 weighted images. Five of the patients were also examined with ultrasonography (US); in four of these, the tumor could be recognized by its echodense pattern. Computed tomography (CT) was slightly less sensitive; three out of six examinations failed to produce a definite diagnosis. Instead of the typical low attenuation values of fat, Hounsfield units similar to either muscle or kidney tissue were observed in these 3 cases. In conclusion, the specific diagnosis of angiomyolipoma depends on the amount of fatty tissue present at MRI, CT, and sonography.

[Follow-up of combined radiotherapy and chemotherapy of advanced bladder cancer using magnetic resonance tomography. Initial results]

A combination of cis-platinum and radiotherapy was applied in five patients with advanced bladder carcinomas. The patients were examined by nuclear magnetic resonance imaging prior to and following therapy. Corresponding to cell-kinetic considerations regarding tissues with slow cell turnover, a maximum therapy effect is shown about nine months after the end of local therapy. Smaller control intervals are recommended in case of bladder carcinomas with lymph node metastases. Due to the possibility of multiple slice imaging, the nuclear magnetic resonance technique is particularly suited for the monitoring of bladder carcinomas. Sagittal and coronary slices show a better image of tumoral extension at the roof and floor of the bladder than axial computed tomography. Lymph node metastases are represented relatively late by both methods.

[31-P-spectroscopy as a method for studying biochemical changes in skin tumors: exemplified by malignant melanoma and squamous cell carcinoma]

We report on the basic principles concerning in vivo P-31 MR spectroscopy and give a short review of the corresponding studies on skin tumors described in the literature. Malignant melanoma and squamous cell carcinoma are both characterized by high concentrations of phosphomonoester and phosphodiester. By means of the P-31 spectroscopy technique, we are able to detect changes regarding the tumor metabolism as a response to chemotherapy, irradiation, or biological immune modifiers (e.g. interferon).

[Importance of contrast medium administration in determining the age of traumatic renal hemorrhage by NMR tomography--experimental results]

In eleven Han-Wistar rats, experimental renal haematomas were produced and scanned by magnetic resonance tomography at two hours to 21 days. Bleeding during the first three or four days showed prolongation of T1 and T2 relaxation times. On subsequent days there was shortening of the T1 and T2 times. Gadolinium DTPA produced a marked effect in the second to fourth day following the trauma, if the examination was carried out 90 to 120 minutes after the administration of contrast medium. Gadolinium can be used in determining the age and clarifying the differential diagnosis of an bleeding if there is clinical support.

[Spin-echo sequences and rapid image sequences in a comparison of spinal diseases]

Rapid image sequences of the spine were compared with proton and T2-weighted spin-echo sequences in 30 patients concerning their diagnostic value and image contrast. The rapid series was carried out with an angle of rotation of 30%, TR of 21 and TE of 12 msec., the spin-echo sequences with a TR/TE of 2,000/20/80 msec. The quality and contrast of the rapid series was markedly inferior to the spin-echo sequences; this was particularly marked for demonstrating disc and bone degeneration. At present, the routine use of rapid sequences cannot be recommended as a substitute for spine-echo examinations.

MR imaging in multiple sclerosis: comparison with clinical, CSF, and visual evoked potential findings

MR examinations of 136 patients with multiple sclerosis (MS) were evaluated to correlate the results with clinical, CSF, and visual evoked potential (VEP) findings. In addition, 22 of the 136 patients were studied several times during a 5-month follow-up period. It was demonstrated that MR is superior to CSF and VEP findings in establishing cerebral alterations in MS. A relationship between the results of CSF and VEP examinations and the MR results could not be detected. Negative CSF and VEP results corresponded to positive MR imaging and vice versa. In our series, five negative MR results were obtained in patients with clinically proved MS. The extent of alterations shown up by MR corresponds to the duration of the disease; in particular, more confluent abnormalities in the periventricular region were found in patients with long-standing disease. More plaques were found in patients with a primary relapsing/remitting course of the disease than with the primary chronic progressive form. The clinical course and the grade of disability did not correspond to differences in MR imaging. Follow-up demonstrated that most lesions remain unchanged (72-79%); increases and decreases in the size of the plaques seem to depend on the clinical course. These results suggest that MR is the most sensitive technique for establishing the diagnosis of MS.

Magnetic resonance imaging in evaluating focal liver lesions

We report the results of magnetic resonance imaging (MRI) of the liver in 46 patients with various previously confirmed focal lesions. A characteristic signal pattern was found in hemangiomas (n = 11), with marked signal hyperintensity on T2 and proton weighted images as compared to normal liver tissue. Cysts (n = 7) also showed marked hyperintensity on T2 images, but could easily be differentiated by a lesser intensity on proton weighted images and signal hypointensity on T1 weighted images. Primary liver tumors (n = 4), metastatic liver disease (n = 18), focal nodular hyperplasia (n = 5), and liver adenoma (n = 1) revealed a weak signal hyperintensity on T2 images, with varying signals in T1 and proton weighted modalities. These data combined with other recent communications in the literature indicate that MRI is a promising diagnostic technique in the detection of focal liver lesions and that it may offer a high degree of specificity in the diagnosis of hepatic hemangiomas and benign cysts.

[NMR tomographic studies in experimental renal vein ligation]

Experimental ligation of the renal veins in rats indicate highly significant and characteristic changes within two hours, consisting of significant prolongation of T2 relaxation time in the cortex and T2 shortening in the medulla. In addition, there is a considerable increase in the size of the kidney, due to swelling of the cortex. T2 prolongation of the cortex is most marked between 30 hours and two to four days after ligation of the vein. In the following weeks there is a return to normal. T2 of the medulla at two to three weeks after ligation shows highly significant reduction compared with the normal side and, at this time, the size of the experimental kidney is significantly less than the opposite kidney. These results indicate that magnetic resonance tomography is a highly sensitive method for the early demonstration of renal vein thrombosis.

[Nuclear spin tomography and computerized tomography in malignant hypernephroma]

Forty patients with histologically confirmed hypernephromas were examined by MR and CT. As regards T-staging, MR had an accuracy of 97% and CT of 91%; for N-staging, MR had an accuracy of 85% and CT of 91% and, with regard to infiltration of the renal vein, MR was correct in 88% of cases and CT in 81%. MR was most accurate in the pre-operative assessment of tumour spread, demonstrating caval involvement in 100% and lymph node metastases in 97%. On the other hand, infiltration of the renal pelvis could be assessed in only 65% of cases; in 27% the assessment was not possible and in 8% one could not be certain. CT proved to be at its best for staging of lymph nodes, but in 15% it was not possible to identify infiltration of the renal vein. MR was not greatly superior to CT in the preoperative diagnosis and staging of hypernephromas.

[Significance of nuclear magnetic tomography in the diagnosis of lumbar disk displacements]

In a prospective study we determined the validity of MRI (Magnetic Resonance Imaging) in lumbar disc herniations. MRI and CT were compared in 34 patients who underwent operation and 8 patients who underwent discography and intradiscal injection. By this study we determined the validity of CT and MRI being more than 90%.