Computed tomography (CT) and magnetic resonance imaging (MRI) in T-stage evaluation of oral and oropharyngeal carcinomas.

174 CT and 32 MRI investigations were carried out on patients with carcinomas of the mouth and oropharynx. The methods were compared and their value in predicting the pre-therapeutic T-staging studied. The combination of CT and clinical examination was able to improve the T-staging considerably compared with clinical examination alone. MRI was superior to CT in delineating the tumour margins in 78% of patients. T1-weighted and gradient echo sequences after intravenous gadolinium injection were particularly useful. Nevertheless, T-staging based on clinical and CT-findings was changed in only 5% of patients by MRI. MRI is especially useful in T1 tumours and in cancer of the base of the tongue. MRI should also be used instead of CT were dental fillings obscure the region of interest. If there are good MRI facilities and an experienced team available MRI can be used before CT.     

Surpass Flow Diverter in the Treatment of Intracranial Aneurysms: A Prospective Multicenter Study

BACKGROUND AND PURPOSE:Incomplete occlusion and recanalization of large and wide-neck brain aneurysms treated by endovascular therapy remains a challenge. We present preliminary clinical and angiographic results of an experimentally optimized Surpass flow diverter for treatment of intracranial aneurysms in a prospective, multicenter, nonrandomized, single-arm study.MATERIALS AND METHODS:At 24 centers, 165 patients with 190 intracranial aneurysms of the anterior and posterior circulations were enrolled. The primary efficacy end point was the percentage of intracranial aneurysms with 100% occlusion on 6-month DSA. The primary safety end point was neurologic death and any stroke through a minimum follow-up of 6 months.RESULTS:Successful flow-diverter delivery was achieved in 161 patients with 186 aneurysms (98%); the mean number of devices used per aneurysm was 1.05. Clinical follow-up (median, 6 months) of 150 patients (93.2%), showed that the primary safety end point occurred in 18 subjects. Permanent neurologic morbidity and mortality were 6% and 2.7%, respectively. Morbidity occurred in 4% and 7.4% of patients treated for aneurysms of the anterior and posterior circulation, respectively. Neurologic death during follow-up was observed in 1.6% and 7.4% of patients with treated intracranial aneurysms of the anterior and posterior circulation, respectively. Ischemic stroke at ≤30 days, SAH at ≤7 days, and intraparenchymal hemorrhage at ≤7 days were encountered in 3.7%, 2.5%, and 2.5% of subjects, respectively. No disabling ischemic strokes at >30 days or SAH at >7 days occurred. New or worsening cranial nerve deficit was observed in 2.7%. Follow-up angiography available in 158 (86.8%) intracranial aneurysms showed 100% occlusion in 75%.CONCLUSIONS:Clinical outcomes of the Surpass flow diverter in the treatment of intracranial aneurysms show a safety profile that is comparable with that of stent-assisted coil embolization. Angiographic results showed a high rate of intracranial aneurysm occlusion.

Previous in vivo and in vitro hemodynamic experimental studies showed that optimization is required to balance the porosity (metal-free/metal area) and pore or mesh density (number of pores/mm²) of flow diverters (FDs) to optimize the effect on flow reduction within the aneurysm sac while keeping the side branches (perforators) patent.^1–6 We evaluated, in a multicenter, prospective, nonrandomized study, our hypothesis that a single optimized FD would suffice to obliterate a variety of aneurysms located in the anterior and posterior circulation without occluding perforators.     

Magnetic resonance imaging–based volumetry differentiates idiopathic Parkinson's syndrome from multiple system atrophy and progressive supranuclear palsy

By using three-dimensional magnetic resonance imaging–based volumetry, we studied atrophy of the caudate nucleus, putamen, brainstem, and cerebellum in patients with idiopathic Parkinson's syndrome (IPS, n = 11), progressive supranuclear palsy (PSP, n = 6), and multiple system atrophy with predominant parkinsonism (MSA-P, n = 12) or ataxia (MSA-C, n = 17). Patients were compared with a total of 46 controls, of whom 16 were age matched. Mean striatal, cerebellar, and brainstem volumes were normal in patients with IPS. We found significant reductions in mean striatal and brainstem volumes in patients with MSA-P, MSA-C, and PSP, whereas patients with MSA-C and MSA-P also showed a reduction in cerebellar volume. On an individual basis, volumes of structures in patients with MSA and PSP showed an extensive overlap with the normal range with the exception of brainstem volumes in patients with MSA-C. Therefore, groups could not be discriminated on the basis of individual structure volumetry. Application of stepwise discriminant analysis, however, allowed discrimination of all 12 patients with MSA-P, 15 of 17 patients with MSA-C, and 5 of 6 patients with PSP from the normal and IPS cohorts. However, patients with IPS could not be separated from controls and patients with MSA-P could not be separated from patients with PSP. In conclusion, total intracranial volume–normalized magnetic resonance imaging–based volumetric measurements provide a sensitive marker to discriminate typical and atypical parkinsonism. Ann Neurol 1999;45:65–74     

Ultrasonography and contrast-enhanced MRA in ICA-stenosis: is conventional angiography obsolete?

Background The standard techniques for the screening and staging of internal carotid artery (ICA) stenosis are Doppler (continuous wave) and Duplex sonography. For the imaging of ICA occlusive disease, magnetic resonance angiography (MRA) is replacing digital subtraction angiography (DSA). The purpose of this observational study was to assess whether contrast enhanced MRA (CE-MRA) combined with ultrasound provided sufficient information for the planning of surgical treatment. Methods CE-MRA was performed in 195 patients (mean age 67.5 years) with sonographic evidence of severe ICA stenosis. The MRA examination protocol contained a heavily T1-weighted contrast bolus enhanced 3D-gradient echo sequence. The degree of stenosis was estimated retrospectively by two experienced neuroradiologists who were blinded to the sonographic findings. Results The consistency of MRA and ultrasound was sufficient to plan thrombendarterectomy in 182/195 patients. The estimations of the degree of stenosis were congruent between MRA and ultrasound in 91 % of 197 vessels with high-degree carotid artery stenosis. CE-MRA evaluation had a high interobserver agreement. In 3 cases ultrasound examination diagnosed a filiform ICA stenosis which was not visible with MRA. In all these cases, DSA and the intraoperative findings revealed very short (1–2 mm), high-grade, excentric stenosis. CE-MRA correctly detected patency in 5 patients with high-grade and low-flow carotid artery stenosis, which had been regarded as occluded by ultrasound. Conversely with, in CE-MRA two occluded vessels were falsely considered as open. Conclusions The combination of sonography and CE-MRA is a powerful tool for the non-invasive presurgical evaluation of the carotid arteries. DSA should be reserved for selected cases. Received: 10 October 2000, Received in revised form: 2 January 2001, Accepted: 10 January 2001     

ICP monitoring with a re-usable transducer: Experimental and clinical evaluation of the Gaeltec ICT/b pressure probe

Summary Intracranial pressure monitoring requires reliable transducers at a justifiable price. At present, transducers for single or repeated use are available. We examined the Gaeltec model ITC/b solid state miniature transducer experimentally and clinically. Measurement accuracy was assessed in vitro at increasing steps of 5 mmHg from 0 to 80 mmHg. While new and recently serviced probes revealed minimal deviations from the preset values, frequently used transducers differed up to 7 mmHg. This occured especially in the high pressure range above 50 mmHg. Additionally the drift was investigated at different pressure levels. After 24 hours we already found drifts of 2 mmHg with new and serviced probes and up to 4 mmHg with used ones. In clinical practice we implanted 150 transducers in 121 patients from 1983 until 1995. The probes were re-used up to twelve times, the average time being 7 times, 32.7% of all measurements were regarded as not reliable. Dislocation (16.7%), inability to calibrate (3.3%) and defect pressure probes (3.3%) were the most common complications. Repeated use of the Gaeltec ICT/b probe also seemed to result in an additional decay of measurement quality. The strain of frequent cleaning and sterilizing may have caused changes of the physical properties of the probes with time. Whether these results also apply to other types of ICP probes for repeated use needs further evaluation.     

Clinical and genetic analysis of three German kindreds with autosomal dominant cerebellar ataxia type I linked to the SCA2 locus

The detailed clinical, electrophysiological and imaging data of three German autosomal dominant cerebellar ataxia (ADCA) families are reported. Linkage to SCA2 was established using microsatellite markers D12S105, D12S1339(1328), D12S1340(1329) yielding a lod score exceeding +3.0 for the combined data. Analysis of the pedigree data provided evidence of anticipation as observed in other neurodegenerative disorders due to polyglutamine expansion encoded by a CAG repeat. This hypothesis was confirmed by the detection of the SCA2-specific pathological protein using the 1C2 monoclonal antibody which selectively recognizes large polyglutamine expansions and the characterization of a CAG expansion in the patients. Clinically, the families were characterized by progressive ataxia of stance, gait and limbs. Saccade velocity was markedly reduced in SCA2. Further oculomotor findings were gaze palsy, impaired smooth pursuit and reduced optokinetic reflex. Dementia and pyramidal tract signs were rather rare, while peripheral involvement (reduced or absent ankle reflexes, fasciculation-like movements, amyotrophy) was a prominent feature. Electrophysiological investigations provided evidence of sensory neuropathy of the axonal type and degeneration of the posterior columns. Imaging studies demonstrated severe shrinkage of brain-stem structures even in early stages of the disease. Received: 10 September 1996 Accepted: 8 December 1996     

Interdisziplinäres Konzept zur Diagnostik und Therapie gefäßreicher Fehlbildungen im Gesichts- und Halsbereich

Purpose. In patients with extended vascular anomalies in the head and neck, therapeutic decisions may pose a challenge to maxillofacial surgeons, dermatologists, and interventional radiologists. We analyzed the value of an interdisciplinary classification and treatment concept. Patients and methods. The classification distinguishes hemangiomas and vascular malformations. Whereas hemangiomas are endothelial proliferations, vascular malformations are considered to be developmental anomalies, which are further classified into high-flow or low-flow lesions and according to the vascular channels into capillary, venous, or lymphatic malformations. Since 2000 we have provided interdisciplinary consultation for patients with vascular anomalies. In patients with hemangiomas and venous malformations, the clinical diagnosis is confirmed by color-coded duplex sonography and magnetic resonance imaging; angiography is performed as part of the treatment planning for patients with arteriovenous malformations. Patients with hemangiomas are treated surgically by cryosurgery or laser surgery or conservatively according to lesion size and behavior. In patients with venous malformations, percutaneous sclerotherapy is combined with surgical reduction; patients with arteriovenous malformations undergo transarterial embolization prior to surgical excision of the nidus. Results. A total of 73 patients attended the interdisciplinary consultation. This group included 53 patients with facial hemangiomas, 7 with venous malformations, 2 with capillary malformations, 5 with lymphatic malformations, and 6 with high-flow arteriovenous malformations. Conclusions. The interdisciplinary protocol increases diagnostic accuracy and helps to establish individual treatment plans for patients with extended vascular anomalies.     

Experimental investigation of intravascular OCT for imaging of intracranial aneurysms

Purpose

Rupture risk assessment of an intracranial aneurysm (IA) is an important factor for indication of therapy. Until today, there is no suitable objective prediction method. Conventional imaging modalities cannot assess the IA’s vessel wall. We investigated the ability of intravascular optical coherence tomography (OCT) as a new tool for the characterization and evaluation of IAs.

Materials and methods

An experimental setup for acquisition of geometrical aneurysm parameters was developed. Object of basic investigation was a silicone phantom with six IAs from patient data. For structural information, three circle of Willis were dissected and imaged postmortem. All image data were postprocessed by medical imaging software.

Results

Geometrical image data of a phantom with six different IAs were acquired. The geometrical image data showed a signal loss, e.g., in aneurysms with a high bottleneck ratio. Imaging data of vessel specimens were evaluated with respect to structural information that is valuable for the characterization of IAs. Those included thin structures (intimal flaps), changes of the vessel wall morphology (intimal thickening, layers), adjacent vessels, small vessel outlets, arterial branches and histological information.

Conclusion

Intravascular OCT provides new possibilities for diagnosis and rupture assessment of IAs. However, currently used imaging system parameters have to be adapted and new catheter techniques have to be developed for a complete assessment of the morphology of IAs.

     

Performance evaluation of a C-Arm CT perfusion phantom

Purpose Brain perfusion measurement in stroke patients provides important information on the infarct area and state of involved tissue. Interventional C-Arm angiography systems can provide perfusion measurements. A CT perfusion phantom was developed for C-Arm perfusion imaging to test and evaluate this method and to aid in the design and validation of scan protocols. Methods A phantom test device was designed based on the anatomy of the human head. Four feeding arteries divided into sixteen sub-branches that lead into a sintered board simulating brain parenchyma. Perfusion measurements were performed using two conventional clinical CT scanners as the gold standard and with a C-Arm CT system to test and compare the implementations. The phantom’s input parameters, contrast medium and flow properties were varied. A cerebral perfusion deficit was simulated by occlusion of a feeding artery tube. Results CT perfusion maps of the sintered board brain tissue surrogate were computed and qualitatively compared for both conventional CT and C-Arm CT systems. A characteristic flow pattern of the tissue board was identifiable in both modalities. The characteristic flow pattern of the resulting perfusion maps is reproducible. The calculated flow and volume were directly related. Conclusions A new CT perfusion phantom was developed and tested. This phantom is an appropriate model for CT-based tissue perfusion measurements in both conventional CT scanners and C-Arm CT scanners. The influence of input parameter changes can be visualized. Perfusion deficits after occlusion of a feeding artery are readily simulated and identified with CT.