Franz A. Fellner

Congenital anomalies of the coronary arteries: imaging with contrast-enhanced, multidetector computed tomography

The objective of this study is to evaluate multidetector CT (MDCT) in detecting and characterizing anomalous coronary arteries. Forty-four patients with anomalies of the coronaries were selected from a total of 1758 individuals examined with ECG-gated 4- and 16-row MDCT including thinMIP, MPR and VRT post-processing. Twenty-eight patients showed origin and course anomalies of the central coronary segments, and in this subgroup 13 were judged as “malignant” because of interarterial courses between the aortic root and the pulmonary trunk, either of the right coronary artery (n=11) or the left coronary artery (n=2). Twelve non-hemodynamic anomalies were found, affecting the coronary origins only (n=10) or the peripheral vessels courses (n=2). Four arteriovenous fistulas were present, all of them with complex arterial feeders. Regardless of vessel anatomy, coronary opacification was always possible by means of the systemic contrast agent, and the aberrant coronary arteries were visualized synoptically in direct relation to the great mediastinal vessels. In contrast to MDCT, selective cannulation and final diagnosis was possible in only 11 of the 20 catheter angiograms performed (accuracy of 55.0%). In conclusion, its non-invasiveness and precise visualization makes MDCT the standard of reference for evaluating anomalous coronary arteries.

High-Resolution, Contrast-Enhanced Magnetic Resonance Angiography With Elliptical Centric k-Space Ordering of Supra-aortic Arteries Compared With Selective X-Ray Angiography

Background and Purpose— The objective of this study was to evaluate the relative value of high-resolution, contrast-enhanced MR angiography (CE MRA) with elliptical centric k-space ordering compared with intra-arterial x-ray angiography for imaging carotid stenosis. Methods— Thirty patients with suspected stenosis of the carotid arteries were examined with CE MRA (1.5-T scanner) and x-ray angiography (aortic arch survey and selective imaging of both common carotid arteries). For the first time, not only the extracranial carotid bifurcation but all the vessel segments from the aortic arch to the circle of Willis were assessed by independent investigators. Results— For the internal carotid artery in the region of the extracranial carotid bifurcation, there was a very close correlation between CE MRA and x-ray angiography (sensitivity, 100%; specificity, 92%). The initially suspected overestimation of stenosis on CE MRA in 3 cases was ultimately revealed to be an underestimation on x-ray angiography. CE MRA showed slightly poorer imaging of the basal vessel segments at the level of the aortic arch (because of breathing artifacts) and the intracranial vessel segments (because of small vessel caliber and venous superimposition due to delayed sequence starts). Conclusions— The MRA technique described here provides reliable results in the diagnosis of carotid stenosis and is thus suitable for replacing the invasive conventional x-ray angiography method in most cases. Further technical developments with regard to spatial resolution are still required for improved visualization of small vessels (terminal carotid branches and intracranial vessels).

Cerebral cavernous malformations associated with venous anomalies: surgical considerations.

OBJECTIVE: Once thought to be rare entities, mixed cerebrovascular malformations with pathological features of more than one type of malformation within the same lesion are now being recognized with increasing frequency. Their identification generates several hypotheses about common pathogenesis or causation-evolution among different types of lesions and leads to controversial discussion on therapeutic strategies. METHODS: Fifteen patients drawn from a consecutive series of 58 patients harboring cavernous malformations (25.9%) were found to have an associated venous malformation (VM). Three (33.3%) of the first 9 patients, in whom the large draining vein of the VM had been left untouched at previous interventions, developed recurrent and/or de novo lesions. RESULTS: Histopathological analysis, interestingly, revealed that the new lesions were different in nature (three arteriovenous angiomas in two patients, a capillary telangiectasia in one patient). During extirpation of the new malformation, the draining vein of the VM in these three patients could be coagulated without any adverse events. Coagulation and dissection of the draining vein of the associated VM was performed in six more patients of our series, and this has prevented development of new lesions up to now. CONCLUSION: Our results are in favor of the hypothesis that the draining vein of a VM is the actual underlying abnormality of mixed vascular malformations. Causing flow disturbances and having the potential for hemorrhages, the VM seems to promote the development of new adjacent malformations. Thus, permanent cure of associated malformations might depend on the surgical treatment of the VM. We present a preliminary personal series and a thorough review of the literature.

Imaging and staging of avascular osteonecroses at the wrist and hand

Avascular ostenecroses (AVN) are unspecific focal sceletal lesions of vascular origin. At the wrist, AVNs are mainly seen in the lunate (Kienbocks disease) and the proximal scaphoid fragment in the presence of a nonunion disease (pseudarthrosis). Other types of osteonecroses are rare. The natural process of devitalization proceeds in steps: initially, there is a bone marrow oedema, followed by trabecula sclerosis, cystic transformation of the spongiosa, and bone fragmentation. End stages include carpal collapse (SLAC wrist) and osteoarthritis. For imaging of the sceletal morphology in AVN computed tomography is most useful, whereas initial stages and perfusion damages are better detected with contrast enhanced magnetic resonance imaging (MRI). In this paper a staging classification for Kienböcks disease and the scaphoid nonunion, considering the diagnostic and therapeutic consequences, is presented.

Magnetic resonance angiography of the carotid arteries using three different techniques: Accuracy compared with intraarterial x-ray angiography and endarterectomy specimens†

To compare three different magnetic resonance angiography (MRA) techniques with x‐ray angiography and endarterectomy specimens.

Fluoroscopically triggered contrast-enhanced 3D MR DSA and 3D time-of-flight turbo MRA of the carotid arteries : first clinical experiences in correlation with ultrasound, x-ray angiography, and endarterectomy findings

The aim of this article was to obtain initial experiences with fluoroscopically triggered contrast-enhanced (CE) 3D MR DSA with elliptical centric k-space order and 3D time-of-flight (TOF) turbo MRA of the carotid arteries. In this prospective study we examined 16 consecutive patients with suspicion of atherosclerotic disease involving the carotid arteries. Ultrasound was available in all, x-ray angiography in 12, surgical correlation in 9, and intraoperative x-ray angiography in 4 patients. All examinations were done on a 1.5 T unit applying: transverse plain 3D TOF turbo MRA and coronal CE MRA with fluoroscopic triggering. Combining head and neck array coils allowed the visualization of supraaortic arteries from the aortic arch to the circle of Willis. MRA results (maximum intensity projections) were compared with x-ray angiography, ultrasound, and inspection of endarterectomy specimens. Volume rendering was performed in selected cases additionally. Agreement between CE MRA, 3D TOF turbo MRA and x-ray angiography regarding stenoses of the internal and external carotid artery was very good. CE MRA was able to detect correctly intracranial stenoses, but delineation of the aortic arch and proximal common carotid arteries was sometimes reduced. Volume rendering was suited for visualization of MRA images providing a realistic three-dimensional impression. In conclusion, high-resolution fluoroscopically triggered CE MRA as non-invasive technique is another important step on the way to replace invasive x-ray angiography for the evaluation of atherosclerotic carotid artery disease. High resolution 3D TOF turbo MRA might be a helpful adjunct to increase the diagnostic reliability for the carotid bifurcation.

Dumbbell-shaped hypoglossal schwannoma. A case report

Dumbbell-shaped neuromas of the 12th cranial nerve extending intra- and extracranially are extremely rare. The present paper reports on a 32-year-old patient who presented with hypoglossal nerve palsy and a two-year history of headache. MRI showed inhomogeneous contrast agent enhancement in a tumor that was partly cystic, partly solid, in the cerebellopontine cistern. The tumor, with its main lesion mass located in the parapharyngeal space, extended along the canal of the hypoglossal nerve. The tumor was excised by two-stage suboccipital osteoclastic craniotomy and later through a cervical approach. Pathohistology showed a grade I schwannoma and the patient was discharged symptom-free without any further therapy.

Ultrasonographic analysis of arteriosclerotic plaques in the internal carotid artery

OBJECTIVES The aim of this study was to investigate whether ultrasonography can characterise plaque morphology and surfaces independent of the observer. METHODS Computer-assisted image analysis of the grey scales of B-mode scans from 15 patients with stenoses of the internal carotid artery was performed and compared with the histopathological reports. In vitro angioscopy, was used to visualise the plaque surfaces of the thromboendarterectomy specimens. RESULT Assessment of the internal plaque structure by ultrasound showed close agreement between the two observers (P<0.01) without correlation with the histopathological results. Ultrasonography was able to characterise the plaque surfaces in 93% of cases. CONCLUSION This investigation showed that standardised computer-assisted analysis of the internal plaque structure correlates less closely than histological investigation, but agrees closely with the surface structure of the plaque. The exclusive use of digital image processing and standardisation of the investigative technique are expected to provide even better results.

BLADE in Sagittal T2-Weighted MR Imaging of the Cervical Spine

BACKGROUND AND PURPOSE: Image quality and diagnostic reliability of T2-weighted MR images of the cervical spine are often impaired by several kinds of artifacts, even in cooperative patients. The aim of this study was to evaluate if BLADE sequences might solve these problems in a routine patient collective. MATERIALS AND METHODS: TSE and BLADE sequences were compared in 60 patients for T2-weighted sagittal imaging of the cervical spine. Image sharpness, motion artifacts, truncation artifacts, metal artifacts, CSF flow phenomena, contrast of anatomic structures (vertebral body/disk, spinal cord/CSF), and diagnostic reliability of spinal cord depiction were evaluated by 2 independent readers. Another 2 readers selected the sequence they would prefer for diagnostic purposes. Statistical evaluations were performed by using the Wilcoxon and the χ2 test; differences with P < .05 were regarded as statistically significant. RESULTS: BLADE was significantly superior to TSE regarding image sharpness, image contrast, diagnostic reliability of spinal cord depiction, motion artifacts, CSF flow phenomena, and truncation artifacts; for metal artifacts no significant improvements were found. In 50 of 60 patients, BLADE was preferred for diagnostic purposes, and TSE was favored in 3 patients. The number of examinations that were nondiagnostic due to impaired spinal cord depiction was reduced from 12 in TSE to 3 in BLADE, and nondiagnostic examinations due to overall motion artifacts were reduced from 2 to 1. CONCLUSIONS: Using the BLADE sequence for sagittal T2-weighted imaging of the cervical spine proved to be advantageous to reduce various kinds of artifacts.

Thrombolysis Beyond the Guidelines Two Treatments in One Subject Within 90 Hours Based on a Modified Magnetic Resonance Imaging Brain Clock Concept

Background and Purpose— We report the first case of 2 intravenous thrombolysis treatments within 90 hours in a patient with early recurrent stroke. Summary of Review— A 50-year-old man had improved significantly after intravenous thrombolysis for acute stroke. On the fourth day, he deteriorated dramatically because of recurrent stroke. Evidence of vessel reocclusion and profound perfusion/diffusion mismatch constituted the rationale for a second thrombolysis treatment, which resulted in vessel recanalization and significant neurologic improvement. Conclusion— The pathophysiological information obtained by multimodal magnetic resonance imaging may suit as a brain clock when repeat thrombolysis treatment is considered for early recurrent stroke.