ABSTRACT: The conventional analysis of ballistic gelatine is performed by transillumination and scanning of 1-cm-thick slices. Previous research demonstrated the advantages of colour and radio contrast in gelatine for computed tomography (CT). The aim of this study was to determine whether this method could be applied to head models in order to facilitate their examination. Four head models of about 14 cm in diameter were prepared from two acryl hollow spheres and two polypropylene hollow spheres. Acryl paint was mixed with barium meal and sealed in a thin foil bag which was attached to the gelatine-filled sphere which was covered with about 3-mm-thick silicone. The head models were shot at using 9 mm × 19 expanding bullets from 4 m distance. The models were examined via multislice CT. The gelatine core was removed; the bullet track was photographed and cut into consecutive slices which were scanned optically. CT images were processed with Corel Photo-Paint. Optical and radiological images were analysed using the AxioVision software. The disruption of the gelatine within the head model was visualised by extensive distribution of paint up to the end of the finest cracks and fissures and along the whole bullet track. CT imaging with excellent radio contrast in the gelatine cracks caused by the temporary cavity allowed for multiplanar reconstruction. We conclude that the combination of colour contrast in gelatine with contrast material-enhanced CT facilitates accurate measurements in ballistic head models.
Deutsche Zeitschrift für die Gesamte Gerichtliche Medizin 05/2012; 126(4):607-13. · 2.59 Impact Factor
Clinical Neuroradiology 04/2012; 20(2):113-115. · 1.09 Impact Factor
ABSTRACT: Background and Purpose:Streak artifacts caused by aneurysm clips and coils impede image quality in multidetector computed tomography (MDCT). The
authors propose a technique to minimize these artifacts by gated data reconstruction and shifting the reconstruction window.
Patients and Methods:Intracranial CT angiograms were acquired in the follow-up of six patients with clipped and coiled intracranial aneurysms,
respectively. Images were reconstructed from four consecutive 45° rotated segments with an acquisition time of 52.5ms/segment.
Data acquisition was gated via an external pacemaker cable-connected to the scanner.
Results:Artifact orientation could be rotated by shifting the reconstruction window and interesting vessel segments visualized without
disturbing streak artifacts. This allowed to assess the posterior communicating artery origin in two cases and a middle cerebral
artery aneurysm remnant in another case, respectively. However, due to a higher noise interesting vessel segments were not adjustable in another three patients.
Conclusion:Gated MDCT is a promising technique to reduce the amount and to change the position of artifacts induced by clips or coils.
Hintergrund und Ziel:Metallartefakte, verursacht durch Gefäßclips und -coils beeinträchtigen die Bildqualität im CT. Wir stellen eine neue Methode
zur Artefaktreduktion vor durch Verwendung einer getriggerten Datenakquisition und durch Verschiebung des Rekonstruktionsintervalls.
Material und Methodik:Sechs Patienten mit geclippten bzw. gecoilten intrakraniellen Aneurysmen haben im Rahmen der Nachsorge intrakraniale CT-Angiogramme
erhalten. In den getriggerten Untersuchungen erfolgte die Bilddaten-Rekonstruktion aus vier 45° Rotationssegmenten mit einer
Akquisitionsdauer von 52,5 ms jeweils. Die Triggerung der Datenakquisition erfolgte durch einen externen, am MDCT angeschlossenen
Ergebnisse:Die getriggerte Datenakquisition und die Drehung der Artefakte in den verschiedenen Rekonstruktionsintervallen hat eine verbesserte
Darstellbarkeit der Gefäßsegmente in der Umgebung der Clips/Coils ermöglicht. Auf diese Weise konnten bei drei Patienten das
aneurysmatragende Gefäß bzw. ein Aneurysmarest dargestellt werden. In drei weiteren Fällen waren die interessierenden Gefäßsegmente
aufgrund des höheren Bildrauschens nicht besser visualisierbar.
Schlussfolgerung:Die getriggerte MDCT ist eine erfolgversprechende Technik um die Menge der Metallartefakte zu reduzieren und um die Position
der Artefakte zu ändern.
KeywordsAneurysm-Coil-Clip-Computed tomography-CT angiography-Starburst artifact-Streak artifact-ECG gating-Retrospective tagging-Reconstruction window
Clinical Neuroradiology 04/2012; 20(2):99-107. · 1.09 Impact Factor
The sporadic adult onset ataxias of unknown etiology (SAOA) denote the non-hereditary degenerative adult onset ataxias that
are distinct from multiple system atrophy (MSA).
To define and characterize the clinical phenotype of sporadic adult onset ataxia of unknown etiology (SAOA).
A survey of clinical features, nerve conduction and evoked potentials, autonomic tests, and magnetic resonance imaging (MRI)-based
brain morphometry was conducted in patients with SAOA.
Study subjects were a consecutive sample of 27 patients (11 male, 16 female) who met the diagnostic criteria for SAOA (age
55 ± 13 years; age at disease onset 47 ± 14 years; disease duration 8 ± 7 years).
All patients presented with a cerebellar syndrome. The most frequent extracerebellar symptoms were decreased vibration sense
in 70% and decreased or absent ankle reflexes in 33% of the patients. Nerve conduction studies revealed a polyneuropathy in
26% of the patients. Somatosensory evoked potentials were abnormal in 44%, and central motor conduction time in 17% of patients.
Autonomic testing revealed an affected autonomic nervous system in 58% of patients. Voxel-based brain morphometry showed a
predominant reduction of gray matter in the cerebellum which was significantly correlated with disease stages. A loss of white
matter was found in both middle cerebellar peduncles and the outer edge of the pons.
The data show that SAOA is a predominantly, but not exclusively cerebellar disorder. Clinical, electrophysiological, and imaging
findings showed some similarities with multiple system atrophy which raises the question of an overlap of these two disorders.
Journal of Neurology 04/2012; 254(10):1384-1389. · 3.47 Impact Factor
Laryngo-Rhino-Otologie 02/2012; 91(6):381-2. · 0.97 Impact Factor
ABSTRACT: 4D-MRA is a promising technique in the diagnosis and follow-up of cAVMs. The purpose of this study was to compare 4D-MRA in the pre- and postoperative evaluation of cAVMs with DSA or intraoperative findings as the standards of reference regarding qualitative and quantitative parameters.
Fifty-six consecutive patients with cAVMs (30 women) underwent both 4D-MRA and DSA. Preoperative 4D-MRA was excluded from analysis in 1 patient (movement artifacts). Twenty-five patients underwent surgery on cAVMs and underwent both imaging modalities pre- and postoperatively. 4D-MRA was performed with either 0.5-mol/L gadolinium-diethylene-triamine pentaacetic acid (group 1: voxel size, 1.1 × 1.1 × 1.4 mm(3); 608 ms/dynamic frame; 19 patients) or 1.0-mol/L gadobutrol (group 2: voxel size, 1.1 × 1.1 × 1.1 mm(3); 572 ms/dynamic frame; additional alternating view sharing; 37 patients). Two readers independently reviewed 4D-MRA and DSA regarding the Spetzler-Martin classification, arterial feeders, and postoperative residual filling. Vessel sharpness, vessel diameter, and VBC of 4D-MRA were quantified.
Preoperative Spetzler-Martin classification 4D-MRA and DSA ratings matched in 55/55 patients (Spetzler-Martin grades: I, 12; II, 22; III, 15; IV, 5; V, 1), and 93/100 arterial feeders were correctly identified by preoperative 4D-MRA (7 additional arterial feeders identified by DSA only: group 1, 3/19; group 2, 4/36). Postoperative 4D-MRA and DSA matched in 25/25 patients (residual filling, 1/25). Vessel sharpness and diameters did not differ substantially between the 2 groups. VBC was significantly higher in group 2 (P < .005).
4D-MRA is a reliable tool that allows predicting Spetzler-Martin classification and postoperative residual filling; it hence allows substituting DSA in the pre- and postoperative evaluation of patients with cerebral AVMs.
American Journal of Neuroradiology 02/2012; 33(6):1095-101. · 2.93 Impact Factor
ABSTRACT: CCSVI has been proposed as a cause for MS. According to this theory, strictures of the IJV are among the described causes for CCSVI. Little is known about their influence on the hemodynamics of the CVBO. We used positional MR imaging to describe the influence of positional changes on the CVBO.
Using the Fonar Upright MR imaging system, we performed venous time-of-flight angiography of the cervical region in the supine and sitting positions in 15 healthy volunteers. The image quality was rated; the positional findings and interindividual variances in the CVBO were analyzed.
A venous time-of-flight angiography of the cervical spine was feasible with good image quality. Strictures of 1 or both IJVs were found in 8 of 15 healthy volunteers in the supine position; however, none were visible in upright position. The IJV was not the main outflow route in the erect position. No relevant venous reflux was observed.
IJV strictures are a common finding in healthy volunteers in the supine position. They seem to be of no relevance in the erect position. This finding questions the validity of this criterion for the diagnosis of CCSVI. Reflux into the venous system was not visualized, and it remains to be seen whether it can be identified in patients with MS. Positional MR imaging enables operator-independent evaluation of the CVBO and may help to clarify the validity of the criteria for CCSVI.
American Journal of Neuroradiology 11/2011; 33(2):246-51. · 2.93 Impact Factor
ABSTRACT: The aim of the study was to examine the effects of mechanical thrombectomy using the Solitaire stent in patients with thromboembolic occlusions of the intracranial carotid artery bifurcation (carotid T) or middle cerebral artery (MCA) and to compare the results with a historical cohort treated with local intraarterial thrombolysis using urokinase.
The time intervals from stroke onset to treatment, recanalization rates, occlusion sites, recanalization times and functional outcomes on the modified Rankin scale at 3 months in 25 patients treated with the Solitaire stent between 2010 and 2011 were evaluated. The data were compared with those of a historical cohort of 62 patients treated with local intraarterial thrombolysis between 1992 and 2001.
A total of 15 out of 25 (60%) patients treated with mechanical thrombectomy and 25 out of 62 (40%) treated with local intraarterial thrombolysis achieved a modified Rankin score of ≤2 (p = 0.07). Occlusion sites, intervals from stroke onset to treatment and rates of parenchymal hematomas, 3 out of 25 (12%) versus 8 out of 62 (13%), were similar in both cohorts while the recanalization rate was significantly higher, 22 out of 25 (88%) versus 33 of 62 (53%), in the mechanical thrombectomy group (p ≤ 0.01).
The data show that mechanical thrombectomy is superior to local intraarterial thrombolysis with respect to the recanalization rate in patients with thrombeoembolic carotid T or MCA occlusions.
Clinical neuroradiology. 10/2011; 22(2):141-7.
Clinical neuroradiology. 08/2011; 21(3):179-80.
Clinical neuroradiology. 04/2011; 21(1):43-4.
Journal of Neuro-Oncology 01/2011; 101(2):343-4. · 3.21 Impact Factor
Clinical neuroradiology. 06/2010; 20(2):113-5.
ABSTRACT: Streak artifacts caused by aneurysm clips and coils impede image quality in multidetector computed tomography (MDCT). The authors propose a technique to minimize these artifacts by gated data reconstruction and shifting the reconstruction window.
Intracranial CT angiograms were acquired in the follow-up of six patients with clipped and coiled intracranial aneurysms, respectively. Images were reconstructed from four consecutive 45 degrees rotated segments with an acquisition time of 52.5 ms/segment. Data acquisition was gated via an external pacemaker cable-connected to the scanner.
Artifact orientation could be rotated by shifting the reconstruction window and interesting vessel segments visualized without disturbing streak artifacts. This allowed to assess the posterior communicating artery origin in two cases and a middle cerebral artery aneurysm remnant in another case, respectively. However, due to a higher noise interesting vessel segments were not adjustable in another three patients.
Gated MDCT is a promising technique to reduce the amount and to change the position of artifacts induced by clips or coils.
Clinical neuroradiology. 06/2010; 20(2):99-107.
International journal of cardiology 05/2010; 145(2):401-2. · 7.08 Impact Factor
ABSTRACT: Due to the proximity of eloquent areas of the brain, the surgical treatment of insular lesions causing refractory epilepsy is considered difficult. We report here on our experience in this field.
We identified 24 patients (age: 1-62 years, mean 27) who underwent epilepsy surgery for an insular lesion from the epilepsy surgery data bank. We analyzed the preoperative diagnostics, surgical strategy and postoperative follow-up (duration: 12-168 months, mean 37.5) for functional morbidity and seizure outcome.
Eight patients had strictly insular lesions while, in 16 cases, the lesion extended into the frontal (n=3) or temporal (n=8) lobe, or was multilobar (n=5). Sixteen resections (66.7%) were right-sided. Six patients required invasive EEG with implanted electrodes, while three had the aid of intraoperative electrocorticography. In 12 patients, continuous electrophysiological monitoring was used intraoperatively (phase reversal, motor evoked potentials) and, in seven, neuronavigation. In seven patients, only subtotal resection of the insular lesion was possible due to involvement of eloquent areas, and two patients required repeat surgery to complete the resection. Thirteen patients had glial/glioneural tumours (WHO grades I-III), 11 from non-neoplastic lesions. Postoperatively, two patients (8.3%) had a transient neurological deficit (hemiparesis and dysphasia, respectively). One patient had permanent hemihypaesthesia, another had permanent deterioration of preexistent hemiparesis and two had hemianopia as calculated deficit (16.6% rate of mild permanent morbidity). According to the International League against Epilepsy (ILAE) classification, 15 patients were totally seizure-free (62.5%, ILAE 1) and 79.2% had a satisfactory seizure outcome (ILAE 1-3).
In selected patients, an individually tailored lesionectomy of insular lesions can be performed, with acceptable safety, to provide a high rate of satisfactory seizure relief. Indeed, even subtotal resection can result in effective seizure control.
Revue Neurologique 09/2009; 165(10):755-61. · 0.49 Impact Factor
ABSTRACT: CSF loss with consecutive intracranial hypotension has been discussed as a possible pathogenetic mechanism in poor clinical outcome after uneventful neurosurgery and appears to be correlated to specific imaging findings. The purpose of this study was to describe the clinical and imaging findings of symptomatic intracranial hypotension likely induced by wound suction drainage.
This is a review of previously published cases of patients in whom this condition developed after uneventful intracranial surgery. We performed an analysis of 3 more cases, of which 2 occurred after spinal surgery with accidental dural opening.
Sixteen patients who remained unconscious or did not become fully responsive after surgery showed symmetric bilateral thalamic/basal ganglia signal intensity changes on CT and MR imaging studies. Of these 16 patients, 4 died and 2 also had brain stem signal intensity changes. All patients had rapid and distinct intraoperative and postoperative CSF loss documented on CT and/or MR imaging studies by a transient increase of the sag ratio, defined as maximal anteroposterior midbrain diameter by maximal bipeduncular diameter.
The clinical course and typical MR imaging findings characterize the disease entity postsurgical intracranial hypotension. These findings also underline the potential danger of wound suction drainage in the case of possible CSF loss.
American Journal of Neuroradiology 09/2009; 31(1):100-5. · 2.93 Impact Factor
Neurology 08/2009; 73(3):247. · 8.31 Impact Factor
ABSTRACT: To evaluate the detectability of the Adamkiewicz artery (AA) in patients with acute Stanford type A aortic dissections with multi-detector computed tomography (MDCT).
51 patients with Stanford type A dissection underwent contrast-enhanced 64-row MDCT of the entire aorta (collimation 64 x 0.625 mm; rotation time 0.4sec; 120 kV; 300 mAs). The visualization of the AA, its origin, and whether it originated from the true or false lumen were analyzed using source and multiplanar reformation images.
A single anterior radicular artery that formed a hairpin turn constituting the anterior spinal artery was visualized in 36 (70 %) patients. Thirty (83 %) of these arteries originated from the left side, and 35 (97 %) originated between the level T 7 and L 2. Twenty-three (64 %) arteries originated from the true and 13 (36 %) from the false lumen. Two AAs in the same patient were not observed.
MDCT depicts the AA in a high percentage of patients with acute Stanford type A aortic dissection.
RöFo - Fortschritte auf dem Gebiet der R 07/2009; 181(9):870-4. · 2.76 Impact Factor
ABSTRACT: Surgical treatment of deep-seated insular lesions causing refractory epilepsy is thought to be difficult due to the complicated accessibility and close proximity of eloquent areas. Here we report our experience with insular lesionectomies. Twenty-four patients (range 1-62 years, mean 27) who underwent epilepsy-surgery for a lesion involving the insular region, were identified from the epilepsy surgery data bank. We analysed pre-surgical diagnostics, surgical strategy and postoperative follow up concerning functional morbidity and seizure outcome (range 12-168 months, mean 37.5). Eight patients had pure insular lesions, in 16 cases the lesion extended either to the frontal (n = 3) or temporal lobe (n = 8) or was multilobar (n = 5). Sixteen resections (66.7%) were done on the right side. Six patients required invasive EEG-recording, three patients received intra-operative electrocorticography. In seven patients only subtotal resection of the insular lesion was possible due to involvement of eloquent areas. Thirteen patients suffered from glial/glioneural tumours (WHO grades I-III), 11 from non-neoplastic lesions. Postoperatively, one patient had a hemihypesthesia and one patient had a deterioration of a pre-existing hemiparesis; two patients had a hemianopia as calculated deficit (mild permanent morbidity 16.6%). According to the ILAE-classification, 15 patients were completely seizure free (62.5%, ILAE 1). Around 79.2% had satisfactory seizure outcome (ILAE 1-3). In selected patients an individually tailored lesionectomy of insular lesions can be performed, which is acceptably safe and provides a high rate of satisfactory seizure relief. Even subtotal resection can result in good seizure control.
Brain 04/2009; 132(Pt 4):1048-56. · 9.46 Impact Factor
ABSTRACT: Spinal dural arteriovenous fistulae (SDAVF) are acquired spinal vascular malformations, in which a small connection between a radicular artery and radicular vein causes venous hypertension, congestive myelopathy and infarction of the spinal cord. Here the case of a 47-year-old man is presented who had pain in his back irradiating to his right leg, numbness of his right leg as well as weakness of both legs. Urination was disturbed with detection of residual urine. Six weeks later he developed a progressive paraparesis of the legs. A T2 weighted MRI of the lower back showed intramedullary hyperintensity. A myelitis was assumed and treatment with acyclovir and dexamethasone was started. Nevertheless, he developed total paralysis of his legs. Six years later, re-evaluation of the initial MRI and a new MRI showed abnormal blood vessels on the dorsal side of the spinal cord, which had been overlooked at the first MRI examination. Spinal angiography demonstrated an arteriovenous fistula. Fistula obliteration was performed. Six months later he was able to stand with canes for 2 min and showed improvement in sensibility. The remarkable aspect of this case of SDAVF is the relevant improvement of complete paraplegia by surgical obliteration 78 months after onset of symptoms. The delay of more than 6 years between onset of first symptoms and final diagnosis underlines the difficulties in making a correct diagnosis of SDAVF. However, even after delayed diagnosis, surgical obliteration should be done, as improvement of neurological function can still be achieved.
Journal of neurology, neurosurgery, and psychiatry 01/2009; 79(12):1408-9. · 4.87 Impact Factor