Picture archiving and communication systems and videoconference for medical communication.

The following summarize the present capability and future potential for telecommunications in radiology: 1. When used as a central archiving, reporting, and directing unit PACS principally leads to an increased economy and centralization and allows a more rational and efficient use of experienced staff and a better education for the young physicians. 2. PACS also have the capability to produce composite imaging, whereby an overall report, consisting of different radiologic examinations can be obtained. The integration of image and text data and the digital link between specialized clinical departments also makes immediate transmission of images and reports possible. 3. Analog and digital videoconferences permit long distance communication and consultation between specialists, without physicians and radiologists having to change location. These television conferences also lead to an important enhancement of education, providing interaction with specialists who might not usually be available.

Dose administration of gadolinium-DTPA in MR imaging of intracranial tumors.

Eleven patients with intracranial tumors were investigated with MR imaging at different dose levels of gadolinium-DTPA to determine a safe and effective dose for imaging intracranial tumors. The patients were divided into two groups. Baseline spin-echo images were obtained with a repetition time of 800 msec and an echo time of 35 msec, and a total of 0.1 mmol of gadolinium-DTPA/kg (six patients) or 0.2 mmol gadolinium-DTPA/kg (five patients) was injected according to a fractionated incremental dose regime (0.025, 0.025, and 0.05 mmol/kg and 0.05, 0.05, and 0.1 mmol/kg, respectively). Postcontrast MR was performed after each injection. In group 1 the best visualization was achieved after the third injection in four cases. In one glioblastoma and in a pituitary adenoma tumor margins were well defined at lower dose levels. In group 2, with five patients, the total dose of 0.2 mmol of gadolinium-DTPA/kg (0.05, 0.05, and 0.1) significantly improved tumor visualization after the third injection in only one patient with multiple metastases. No short-term side effects were encountered. In a range of parameters measured in both serum and whole blood, slight transient elevation of serum iron levels was the only appreciable change. As a result of our investigation we conclude that 0.1 mmol of gadolinium-DTPA/kg is a safe and suitable dose for brain-tumor imaging. In selected cases of 0.2 mmol/kg may increase the diagnostic yield.

Time-dependent changes in image contrast in brain tumors after gadolinium-DTPA.

Time-dependent changes in the contrast enhancement of tumor tissue, tumor necrosis, perifocal edema, and normal brain tissue after IV injection of 0.1 mmol gadolinium-DTPA/kg body weight were studied with spin-echo technique (SE 800/35) in 15 patients with intracranial tumors. Using a region of interest technique, we determined the signal-intensity values of these tissues before and at fixed times up to 68.5 min after administration of the contrast agent. In tumor tissue, the 8.5 min postinjection (p.i.) scan showed a significant increase in signal intensity. The signal intensity of the tumor tissue remained significantly higher than precontrast levels throughout the entire period of observation, decreasing only slightly toward the end of the examination (48.5 and 68.5 min p.i.). Central tumor necrosis exhibited a delayed uptake of the contrast agent, with a maximum signal intensity between 48.5 and 68.5 min p.i. In perifocal edema and normal brain tissue, slight increases in signal intensity after injection of gadolinium-DTPA were measured (statistically significant in the case of edema). This effect, however, was not visually detectable. The present study shows that after one injection, scans with excellent tumor visualization can be obtained between 8.5 and 38.5 min p.i. and with diagnostically valid enhancement at least up to 68.5 min p.i.

Administration of gadopentetate dimeglumine in MR imaging of intracranial tumors: dosage and field strength.

PURPOSE: To investigate the efficacy of 0.025, 0.05 and 0.1 mmol/kg gadopentetate dimeglumine in MR imaging of patients with intracranial tumors at mid and high field strength. METHODS: In 88 patients, an open-label phase III multicenter dose-finding study was performed at 0.5, 1.0, and 1.5 T MR units. Before and after (5, 15, 25 minutes) intravenous administration of gadopentetate dimeglumine, imaging was performed with T1-weighted spin-echo sequences. RESULTS: With 0.1 mmol/kg yielding the highest values, tumor enhancement and numerical tumor/brain contrast showed dose-dependent 5-minute postcontrast values (P less than 0.05). Compared to 5-minute postcontrast values, there was no significant change at 15 and 25 minutes. Although the lowest values of enhancement were found at 0.5 T, differences in enhancement among the field strengths were not statistically significant. The numerical data were confirmed by visual assessment of tumor/brain contrast. Eighty to 90% of cases had diagnostically valuable enhancement at 0.1 mmol/kg, 50% at 0.05 mmol/kg, and 10% at 0.025 mmol/kg (P less than 0.05). There were no adverse events. CONCLUSION: Our results confirm that 0.1 mmol/kg gadopentetate dimeglumine is more effective at enhancing intracranial tumors than lower doses at mid and high field MR units.

Hyperostosis in meningiomas: MR findings in patients with recurrent meningioma of the sphenoid wings.

PURPOSE: We used MR imaging to analyze retrospectively the pattern of hyperostosis occurring concomitantly with recurrent sphenoid wing meningiomas. METHODS: Bone involvement was compared in 12 corresponding CT and MR studies of 10 female patients with sphenoid wing meningiomas recurrence after earlier surgical treatment. Four of these had histologically confirmed meningiomatous infiltration of the bone. RESULTS: All patients had CT findings of localized hyperostosis of parts of the sphenoid wings. MR revealed inhomogeneous areas of slightly increased signal intensity in hyperostotic bone on T2-, proton density- and T1-weighted sequences. In nine of 10 patients, segments of the hyperostotic bone showed different degrees of gadolinium enhancement. CONCLUSIONS: Because earlier studies have revealed high incidences of meningiomatous bone infiltration in sphenoid wing meningiomas, and because infiltration was confirmed in four of our patients, we postulate that the gadolinium enhancement in the area of hyperostosis may be related to meningiomatous bone infiltration.

Gadolinium-DTPA in MR imaging of glioblastomas and intracranial metastases.

In 14 patients with the diagnosis of glioblastoma (n = 7) or intracranial metastases (n = 7), magnetic resonance (MR) imaging was performed using a variety of spin-echo (SE) pulse sequences before and after intravenous injection of 0.1 mmol gadolinium-DTPA (Gd-DTPA) per kilogram of body weight. In 10 patients, tumor tissue could not be adequately differentiated from perifocal edema on unenhanced scans with any of the applied pulse sequences. In four cases of intracranial metastases, poor differentiation between tumor and perifocal edema was possible in T2-weighted (SE 1600/70 and SE 1600/105) unenhanced scans. After administration of Gd-DTPA, tumor tissue showed marked contrast enhancement, and tumor delineation was consistently possible on SE 800/35 images. Tumor tissue could be differentiated from perifocal edema on SE 800/70 scans. Gd-DTPA is likely to increase the potential of MR imaging and refine the evaluation of glioblastomas and intracerebral metastases.

Spinal cord cavities: differential-diagnostic criteria in magnetic resonance imaging.

MRI examinations of 30 patients with idiopathic syringomyelia and 10 patients with cavities associated with an intramedullary neoplasm were evaluated with respect to typical MRI features in both groups. All tumor-associated cases resembled the idiopathic syringomyelias in some portions of the cavity. At the tumor site, however, tumor-associated cases demonstrated typical findings: the cavities showed abrupt changes of diameter (10/10) and position (8/10) and the surrounding spinal cord demonstrated an uneven thickness (10/10), an increased signal intensity on T2-weighted images (10/10) and pathological contrast enhancement (7/7). Displacement of cerebellar tonsils below the level of the foramen magnum (21/30) and enlargement of the spinal canal (7/29) were characteristic features of idiopathic cases. In conclusion, MRI provides valuable criteria to differentiate between idiopathic and tumor-associated cavities.

[The scintigraphic investigation of the sacroiliac joints in ankylosing spondylitis ]. / Die szintigraphische Untersuchung der Iliosakralgelenke bei Patienten mit Spondylitis ankylopoetica.

Quantitative sacroiliac scintigraphy was performed in 41 patients with ankylosing spondylitis (Sp.a.) and in 90 control subjects. The sacroiliac/sacrum ratio (Index ISG/sacrum) was calculated. We examined the correlation between activity ratio on the one hand and age, subjective complaints, erythrocyte sedimentation rate, and antiinflammatory therapy on the other. Significantly increased uptakes were found in the patient group as a whole compared with the controls. The activity index was highest in the early periods of the disease, so we conclude that scintigraphy is useful in the early diagnosis of Sp.a.

[Differential diagnosis of focal kidney diseases using nuclear magnetic resonance tomography]. / Differentialdiagnose fokaler Nierenerkrankungen mit der Kernspintomographie.

The value of T1 and T2-weighted spin echo sequences for making a specific diagnosis of focal renal disease was evaluated in 105 MR examinations. Typically, hypernephromas are characterised by a reduced or only slightly increased T1 or T2 signal, whereas previous bleeding and long-standing abscesses result in increased signal strength, particularly with T2-weighted sequences. In this way, hypernephromas can be characterised; this is not always possible with CT. Angiomyolipomas also have characteristic signals. MR has no advantages in the diagnosis of recent bleeding, acute focal inflammatory lesions, metastases, carcinoma of the renal pelvis or atypical cysts.

[Angiographic diagnosis of vascular impotence]. / Angiographische Diagnostik der vaskulär bedingten Impotentia coeundi.

Twelve patients (average age 40 +/- 15 years) with impotentia coeundi were angiographically examined under suspicion of a vasculogenic impotence. Overview angiographies of the pelvis and selective iliaca interna injections were performed. The normal anatomy of the pudendal artery and the penile branches is shown. Ten patients were suffering from a stenosis or total occlusion of the dorsal pudendal artery, the dorsal penile artery or the profound penile artery with or without filling of a peripheral segment. The role of arteriography in surgical treatment is discussed.

[MR imaging of the meninges: normal and pathological findings]. / MR-Darstellung der Meningen: Normale und pathologische Befunde.

The MR appearance of normal and pathological meninges was studied in 23 patients. Amongst twelve normals, T1-weighted images demonstrated the meninges as slightly hyperintense density structures (compared with CSF) which increased in signal intensity somewhat after the administration of gadolinium-DTPA. On T2-weighted images, the subarachnoid space and meninges were isointense. In eleven patients with inflammatory disease or tumourous infiltration of the meninges, abnormal findings were evident in the unenhanced images as well as after administration of gadolinium-DTPA. Compared with CT, MR proved greatly superior in the diagnosis of meningeal abnormalities.

[Indications for magnetic resonance tomography in the diagnosis of cerebral diseases. Report of experiences with 1200 cases]. / Indikationen der magnetischen Resonanztomographie in der Diagnostik zerebraler Erkrankungen. Ein Erfahrungsbericht nach 1200 Untersuchungen.

The current paper is a review of our experience of 1200 examinations of the brain, using magnetic resonance tomography (MRT), derived from a mixed neurological and neuro-surgical clinic. MRT has advantages in localisation and tissue characterisation. Localisation is improved by the ability to obtain coronal and sagittal images and by the absence of artifacts due to bone in lesions in the middle and posterior fossa. Some tissues and structures (blood, fat, vessels) produce relatively characteristic signals on MRT, which may be important in clinical diagnosis (eg. chronic subdural haematoma). A significant advantage of MRT is its excellent contrast resolution of soft tissues; this results in better demonstration of normal brain anatomy (eg. corticomedullary contrast), areas of demyelinisation (eg. multiple sclerosis) and certain cerebral tumours (eg. astrocytomas). On the basis of our experience, certain indications are defined, depending on the physical characteristics of the method; these are illustrated by clinical examples.

[Characteristics of intracranial meningioma imaged by magnetic resonance tomography]. / Charakteristika intrakranieller Meningeome in der magnetischen Resonanztomographie.

Twenty-three patients with intra cranial meningiomas were examined by means of magnetic resonance tomography (MRT). In 13 patients the paramagnetic contrast medium gadolinium DTPA was used. Meningiomas show only slight changes in signal intensity compared with brain in the spin-echo mode, the greatest contrast being found on photon density images (TR 1600 ms, TE 35 ms). In T1 images, more than 50% patients showed a low signal margin between tumour and brain, Hyperostosis of the calvarium is easily recognised, but MRT is unreliable for showing tumour calcification. After intravenous injection of gadolinium DTPA, there was marked homogeneous uptake in the meningiomas. These signs are useful for the diagnosis of a meningioma by MRT.

[Functional scintigraphic blood pool study. A radiologic technic for non-invasive study of pharmacologically induced blood volume fluctuations]. / Die funktionsszintigraphische Bloodpooluntersuchung. Eine radiologische Technik für das nicht-invasive Studium pharmakologisch induzierter Blutvolumenverschiebungen.

After in-vivo labeling of red blood cells with 99mTcO4, the radioactivity of different parts of the body is proportional to the regional blood volume. This technique allows the simultaneous registration of drug-induced changes of the local blood volume. We examined the influence of nitroglycerin on the blood volume distribution in patients with coronary artery disease (n = 10) and chronic heart failure (n = 8). Compared with the controls (n = 8) we observed in the nitroglycerin-groups a significant decrease of blood volume over the heart and the liver, whereas there was an increase of the blood volume over the extremities. It is pointed out that functional whole-body scanning is a useful radiological technique for the non-invasive study of pharmacologically caused changes of the local blood volume in man.

[Value of hypotonic duodenography in pancreatic diagnosis. Comparison with computer-tomographic findings]. / Der Stellenwert der hypotonen Duodenographie in der Pankreasdiagnostik. Ein Vergleich mit computertomographischen Befunden.

61 patients with suggested pancreatic disease were examined by Hypotonic Duodenography (HD) and Computed Tomography (CT). After all examinations had been carried out, 45 patients were found to have an abnormal pancreas, and 16 patients had a normal pancreas. HD had a sensitivity of 60%, and a specificity of 94%, whereas CT had a sensitivity of 78% and a specificity of 100%. - HD is more sensitive than CT in detecting lesions originating from pancreatico-duodenal structures. In patients with uncertain clinical symptoms of the upper gastrointestinal tract HD is still a valuable basic examination. Only in patients with strongly suspected pancreatic carcinoma radiologic examination should start with CT because CT is more sensitive in detecting a pancreatic lesion and is helpful in assessing its extension and defining its etiology.

[Contrast media in magnetic resonance tomography. A review. 1. Physicochemical and pharmacological bases of MR contrast media using gadolinium-DTPA as an example]. / Kontrastmittel in der magnetischen Resonanztomographie. Eine Ubersicht. Teil 1: Physiko-chemische und pharmakologische Grundlagen von MR-Kontrastmitteln am Beispiel von Gadolinium-DTPA.

The principles underlying contrast media for MR tomography are totally different from those for conventional contrast media. Substances suitable for MR tomography are paramagnetic complexes which alter the relaxation times of the tissues. Signal intensity on the MR images are influenced correspondingly. The mode of action of MR contrast media is explained. Gadolinium-DTPA, the first MR contrast medium in clinical use by means of intravenous injection, is described. Its tolerance has been investigated by animal experiments and its effectiveness as an contrast agent has been studied in normal individuals. In the second part of the paper, early results from the use of gadolinium DTPA are given. The additional information which can be obtained by using MR contrast media is discussed.

[Magnetic resonance tomography (MRT) in temporal lobe lesions. Study of patients with psychomotor seizures]. / Magnetische Resonanztomographie (MRT) bei Temporallappenläsionen. Eine Untersuchung von Patienten mit psychomotorischen Anfällen.

A comparative study between magnetic resonance tomography (MRT) and CT was carried out in 16 patients with temporal lobe epilepsy. The MRT studies were performed on a 0.35 T Magnetom with T.1 modes in a coronal plane. MRT proved to the superior to CT. CT demonstrated a discreet temporal lobe lesion in three patients and MRT in four patients. In addition, unilateral atrophy of the temporal lobe was demonstrated by MRT in six cases; these could not be diagnosed by CT. The lack of artifacts near the skull base, the possibility of producing coronal sections and the excellent tissue differential of MRT provide the basis for improved diagnosis of lesions in the temporal lobes.

[MRT of brain metastases. (I) What is the place of screening with T2-weighted sequences?]. / MRT bei Hirnmetastasen. (I) Welchen Stellenwert hat das Screening mit T2-betonten Sequenzen?

Sensitivity and specificity of plain T2-WI and Gd-DTPA enhanced T1-WI were compared by evaluating MR exams of 30 patients with brain metastases. Large lesions with high signal on T2-WI always enhanced (43/43) when a structure (perifocal edema, tumor tissue, central necrosis) was found. Large lesions nearly always enhanced (53/55) even if no such structure was found. 65% of small unstructured white matter lesions with high signal on T2-WI, which are generally considered vascular, did not enhance. Surprisingly, 35% did enhance. Demonstration of blood brain barrier disturbance in these lesions suggested a metastatic origin. In 3 patients with multiple metastases, Gd-DTPA enhanced T1-WI disclosed more than 140 lesions not seen on T2-WI. All of them were located in or adjacent to grey matter. Our results indicate that enhanced T1-WI should be obtained even if T1-WI are normal or show only small white matter lesions.

[Contrast media in magnetic resonance tomography. A review. 2. Biological basis, research technic and clinical application of gadolinium-DTPA in the diagnosis of intracranial tumors]. / Kontrastmittel in der magnetischen Resonanztomographie. Eine Ubersicht. Teil 2: Biologische Grundlagen, Untersuchungstechnik und klinische Anwendung von Gadolinium-DTPA in der Diagnostik intrakranieller Tumoren.

The early results of the use of the MR specific contrast medium gadolinium-DTPA in 40 patients with intracranial tumours are reported. Optimal pulse sequences, contrast dose and timing are discussed. The relationship between the blood-brain barrier and contrast distribution within tumour tissue is elaborated. The clinical significance of the application of contrast agents in the diagnosis of brain tumours is evaluated.

[The rapid magnetic resonance tomography measurement of the contrast medium dilution kinetics (gadolinium-DTPA) in a circulatory phantom]. / Schnelle magnetresonanztomographische Messung von Kontrastmittelverdünnungskinetiken (Gadolinium-DTPA) in einem Kreislaufphantom.

We studied first-pass MRI contrast dilution to compute flow and volume of distribution in a realistic flow phantom. Pulsatile flow was provided by a one-chamber artificial heart. Physiological stroke volume, rate, pressure, and flow were adjustable. An elastic tube with dimensions similar to that of the human aorta was imaged at a rate of 2.4 Hz. After contrast injection, an initial increase in signal intensity was followed by a decrease. Signal-intensity time plots demonstrated slightly skewed curves as expected from dispersion theory. After calibration at different gadolinium-DTPA concentrations, signal intensities were converted into true gadolinium concentrations, and flow was calculated from the concentration-time curves. Flow was varied between 2.5 and 10.0 l/min and a significant correlation was found between the MRI estimate and true flow. Volume of distribution between injection and detection site was reliably estimated. This study demonstrates rapid 2-D imaging of a paramagnetic contrast bolus in a realistic flow phantom. Reliable estimates of flow and volume are obtained.