Interventionelle radiologische Therapie der Tränenwege

Zusammenfassung : Der Augenpatient, in dessen Diagnostik und Therapie der Radiologe involviert ist, leidet gewöhnlich unter ständigem Tränenträufeln, der Epiphora. Die Epiphora ist ein häufiges Krankheitsbild und wird bei ca. 3% aller Patienten einer ophthalmologischen Praxis diagnostiziert. Epiphora ist entweder die Folge einer Überproduktion oder einer Abflussstörung von Tränenflüssigkeit infolge einer Obstruktion im Tränengangsystem. Epiphora wird am häufigsten durch Stenosen oder Verschlüsse des Tränengangsystems verursacht. Die Obstruktion ist meist im Bereich von Saccus und Ductus nasolacrimalis lokalisiert. Während in der Vergangenheit die Therapie ausschließlich operativ mittels Dakryozystorhinostomie erfolgte, wurden mittlerweile interventionelle radiologische Techniken entwickelt, die in bestimmten Fällen eine Alternative darstellen. Um die für den Patienten geeignetste Therapieform zu finden, müssen die genaue Ursache und Lokalisation der Epiphora abgeklärt werden. Hierbei stellt die in digitaler Subtraktionstechnik durchgeführte Dakryozystographie das bildgebende Standardverfahren dar. Im therapeutischen Bereich sind die interventionellen radiologischen Techniken der Dakryozystoplastie gegenüber den operativen Verfahren minimal invasiv, können ambulant und in Lokalanästhesie durchgeführt werden und erhalten die normale Anatomie des Tränenapparats. Zusätzlich kann eine störende Narbenbildung vermieden werden. Bei vergleichbaren technischen und klinischen Erfolgsraten stellt insbesondere die Ballondilatation bei Stenosen eine therapeutische Alternative zur Operation dar. Auch die Stentimplantation ist bereits jetzt eine wertvolle Therapieoption für die Behandlung von Tränenwegsverschlüssen. Die Stentimplantation ist besonders bei den Patienten indiziert, die einer operativen Therapie nicht zugänglich sind oder diese ablehne

Real-time visualization of ultrasound-guided retrobulbar blockade: an imaging study

Background Retrobulbar anaesthesia allows eye surgery in awake patients. Severe complications of the blind techniques are reported. Ultrasound-guided needle introduction and direct visualization of the spread of local anaesthetic may improve quality and safety of retrobulbar anaesthesia. Therefore, we developed a new ultrasound-guided technique using human cadavers. Methods In total, 20 blocks on both sides in 10 embalmed human cadavers were performed. Using a small curved array transducer and a long-axis approach, a 22 G short bevel needle was introduced under ultrasound guidance lateral and caudal of the eyeball until the needle tip was seen 2 mm away from the optic nerve. At this point, 2 ml of contrast dye as a substitute for local anaesthetic was injected. Immediately after the injection, the spread of the contrast dye was documented by means of CT scans performed in each cadaver. Results The CT scans showed the distribution of the contrast dye in the muscle cone and behind the posterior sclera in all but one case. No contrast dye was found inside the optic nerve or inside the eyeball. In one case, there could be an additional trace of contrast dye behind the orbita. Conclusions Our new ultrasound-guided technique has the potential to improve safety and efficacy of the procedure by direct visualization of the needle placement and the distribution of the injected fluid. Furthermore, the precise injection near the optic nerve could lead to a reduction of the amount of the local anaesthetic needed with fewer related complication

Effects of contour propagation and background corrections in different MRI flow software packages

Background: Velocity-encoded magnetic resonance imaging (VENC-MRI) is a commonly used technique in cardiac examinations. This technique utilizes the phase shift properties of protons moving along a magnetic field gradient. VENC-MRI offers a unique way of measuring the severity of valve regurgitation by directly quantifying the regurgitation flow volume. Purpose: To compare flow analysis results of different software programs and to assess the effect of background correction in sample patient cases. Material and Methods: A phantom was built out of Polymethyl methacrylate (PMMA) which provides tubes of different diameters. These tubes can be connected to an external water circuit to generate a water flow inside the tubes. Expected absolute flow quantities inside the tubes were determined from preset tube- and flow-parameters. Different flow conditions were measured with a VENC-MRI sequence and the images evaluated using different software packages. In a second step six randomly selected patients showing different degrees of aortic insufficiency were evaluated in clinical terms. Results: The contour propagation algorithms used in the software packages performed differently even on static phantom geometry. In terms of clinical evaluation the software packages performed similarly. Enabling background correction or leaving out manual correction of propagated contours changed results for severity of aortic insufficiency. Conclusion: Turning on background correction and manual correction of propagated contours in MRI flow volume measurements is strongly recommended

Endovascular Treatment of Anterior Circulation Cerebral Aneurysms by Using Guglielmi Detachable Coils: A 10-Year Single-Center Experience with Special Emphasis on the Use of Three-Dimensional GDC

Purpose:: To analyze the immediate, long-term angiographic and clinical results of endovascular treatment of anterior circulation aneurysms with special regard to the use of three-dimensional Guglielmi detachable coils (3D-GDC). Patients and Methods:: Between 1993 and 2003, 116 patients with 116 anterior circulation aneurysms were treated. 88 patients (75.9%) underwent embolization due to high surgical risk. To analyze the use of 3D-GDC, patients treated before (group 1) and after (group 2) implementation of 3D-GDC in 1999 were compared. Mean duration of angiographic follow-up was 13.9 months. Clinical follow-up was set at hospital discharge and using a questionnaire for long-term follow-up (mean 46.8 months). Results:: Overall, at initial intervention, complete occlusion was achieved in 65 aneurysms (56.0%), neck remnant in 42 (36.2%), and incomplete occlusion in nine (7.8%). Procedure-related permanent morbidity was 4.3% and mortality 2.6%. Recanalization rate at radiologic follow-up was 16.7%. Occlusion success at initial treatment correlated with aneurysm neck size (p = 0.001). Clinical outcome at hospital discharge was dependent on Hunt & Hess grade at presentation (p = 0.01). Subgroup analysis revealed that the use of 3D-GDC produced a higher initial obliteration rate compared to standard coils, but did not reach statistical significance (p = 0.059). Neither aneurysm neck size nor aneurysm dome size nor the use of 3D-GDC significantly influenced recanalization rate. Conclusion:: GDC technology is effective and safe, particularly in case of patients with high surgical risk. Aneurysm neck size was predictive of occlusion rate and Hunt & Hess grade of clinical outcome. Introduction of 3D-GDC probably improved occlusion rate, but did not significantly influence recanalization rat

Retardation of myelination due to dietary vitamin B12 deficiency: cranial MRI findings

Vitamin B12 deficiency is known to be associated with signs of demyelination, usually in the spinal cord. Lack of vitamin B12 in the maternal diet during pregnancy has been shown to cause severe retardation of myelination in the nervous system. We report the case of a 14 1/2-month-old child of strictly vegetarian parents who presented with severe psychomotor retardation. This severely hypotonic child had anemia due to insufficient maternal intake of vitamin B12 with associated megaloblastic anemia. MRI of the brain revealed severe brain atrophy with signs of retarded myelination, the frontal and temporal lobes being most severely affected. It was concluded that this myelination retardation was due to insufficient intake of vitamin B12 and vitamin B12 therapy was instituted. The patient responded well with improvement of clinical and imaging abnormalities. We stress the importance of MRI in the diagnosis and follow-up of patients with suspected diseases of myelinatio

Prospective navigator-echo-based real-time triggering of fetal head movement for the reduction of artifacts

The purpose of this study was to evaluate the neuroimaging quality and accuracy of prospective real-time navigator-echo acquisition correction versus untriggered intrauterine magnetic resonance imaging (MRI) techniques. Twenty women in whom fetal motion artifacts compromised the neuroimaging quality of fetal MRI taken during the 28.7 ± 4week of pregnancy below diagnostic levels were additionally investigated using a navigator-triggered half-Fourier acquired single-shot turbo-spin echo (HASTE) sequence. Imaging quality was evaluated by two blinded readers applying a rating scale from 1 (not diagnostic) to 5 (excellent). Diagnostic criteria included depiction of the germinal matrix, grey and white matter, CSF, brain stem and cerebellum. Signal-difference-to-noise ratios (SDNRs) in the white matter and germinal zone were quantitatively evaluated. Imaging quality improved in 18/20 patients using the navigator echo technique (2.4 ± 0.58 vs. 3.65 ± 0.73 SD, p < 0.01 for all evaluation criteria). In 2/20 patients fetal movement severely impaired image quality in conventional and navigated HASTE. Navigator-echo imaging revealed additional structural brain abnormalities and confirmed diagnosis in 8/20 patients. The accuracy improved from 50% to 90%. Average SDNR increased from 0.7 ± 7.27 to 19.83 ± 15.71 (p < 0.01). Navigator-echo-based real-time triggering of fetal head movement is a reliable technique that can deliver diagnostic fetal MR image quality despite vigorous fetal movemen