Johann Scharf

Publications of Johann Scharf

• Variations of the superior sagittal sinus and bridging veins in human dissections and computed tomography venography.

  Authors: Carolin Brockmann, Sandra C Kunze, Peter Schmiedek, Christoph Groden, Johann Scharf

  Clinical imaging. 03/2012; 36(2):85-9.

  The aim of the present study was to examine the superior sagittal sinus (SSS) and bridging veins (BVs) from an anatomical, neurosurgical and radiological perspective. Computed tomography venographiesThe aim of the present study was to examine the superior sagittal sinus (SSS) and bridging veins (BVs) from an anatomical, neurosurgical and radiological perspective. Computed tomography venographies (CTVs) of 30 patients and 9 cadaveric dissections of human SSS were analyzed. CTV and cadavers showed most BVs emptying into the SSS close by (±3 cm) and distal to the coronary suture (74% in CTV, 62% in cadavers). Important anatomical information can be drawn from cerebral CTV for neurosurgical preoperative planning.

• Computed tomographic angiography of the superior sagittal sinus and bridging veins.

  Authors: Carolin Brockmann, Sandra Kunze, Johann Scharf

  Surgical and radiologic anatomy : SRA. 03/2011; 33(2):129-34.

  The primary aim of our paper was to describe typical anatomical patterns of the superior sagittal sinus (SSS) and bridging veins (BV) using cerebral venous computed tomographic angiography (CTA) withThe primary aim of our paper was to describe typical anatomical patterns of the superior sagittal sinus (SSS) and bridging veins (BV) using cerebral venous computed tomographic angiography (CTA) with a focus on the direction of the BV entering the SSS. We retrospectively analyzed venous CTA of 30 patients to estimate the total number and direction of the BV entering the SSS. Maximum intensive projections were analyzed for length, diameter and cross-sectional area of the SSS. Thee hundred and fifty-four BV were assessed. The mean total length of the SSS was 25.6 ± 1.6 cm (mean ± 1 SD). The mean horizontal diameter at the level of the coronary suture was 6.7 ± 2.0 mm, and the mean vertical diameter at the coronary suture measured 5.3 ± 1.8 mm. Most BV emptied into the SSS, at the level of or distal to the coronary suture (74%). The BV draining into the SSS at the level of the coronary suture typically joined into a lacunar formation (43%). Veins draining into the sinus more than 3 cm distal from the coronary suture presented a predominantly retrograde inflow direction (77%). Despite large variations in the location and course of BV, typical anatomical patterns were noted especially in relation to the direction of BV entering the SSS. The present anatomical analysis of the cerebral convexity veins by cerebral venous CTA provides an overview of the configuration of these veins which is useful information in neurosurgical preoperative planning.

• Abciximab does not prevent ischemic lesions related to cerebral angiography: a randomized placebo-controlled trial.

  Authors: Carolin Brockmann, Thomas Hoefer, Michael Diepers, Eva Neumaier-Probst, Ingo Noelte, Marc-Alexander Brockmann, Christel Weiss, Christoph Groden, Johann Scharf

  Cerebrovascular diseases (Basel, Switzerland). 01/2011; 31(4):353-7.

  To assess the efficiency of IIb/IIIa platelet receptor inhibition by abciximab in the prevention of silent embolism during digital subtraction angiography. In this randomized, double-blind,To assess the efficiency of IIb/IIIa platelet receptor inhibition by abciximab in the prevention of silent embolism during digital subtraction angiography. In this randomized, double-blind, prospective study, pre- and postangiographic diffusion-weighted magnetic resonance imaging (DWI) of 184 participants was evaluated for the occurrence of silent embolism. No significant relationship was found between the patients receiving abciximab before digital subtraction angiography (15 of 90; 16.7%) and patients in the placebo group (16 of 94; 17.0%) regarding postangiographic appearance of silent emboli (p = 0.9). IIb/IIIa receptor inhibition by abciximab does not diminish the occurrence of silent embolism during digital subtraction angiography. Our findings indicate that solid blood clots are not the origin of hyperintense lesions observed on DWI and enhance the role of alternative mechanisms.

• Noise reduction and image quality improvement of low dose and ultra low dose brain perfusion CT by HYPR-LR processing.

  Authors: Radko Krissak, Charles A Mistretta, Thomas Henzler, Anastasios Chatzikonstantinou, Johann Scharf, Stefan O Schoenberg, Christian Fink

  PloS one. 01/2011; 6(2):e17098.

  To evaluate image quality and signal characteristics of brain perfusion CT (BPCT) obtained by low-dose (LD) and ultra-low-dose (ULD) protocols with and without post-processing by highly constrainedTo evaluate image quality and signal characteristics of brain perfusion CT (BPCT) obtained by low-dose (LD) and ultra-low-dose (ULD) protocols with and without post-processing by highly constrained back-projection (HYPR)-local reconstruction (LR) technique. Simultaneous BPCTs were acquired in 8 patients on a dual-source-CT by applying LD (80 kV, 200 mAs, 14×1.2 mm) on tube A and ULD (80 kV, 30 mAs, 14×1.2 mm) on tube B. Image data from both tubes was reconstructed with identical parameters and post-processed using the HYPR-LR. Correlation coefficients between mean and maximum (MAX) attenuation values within corresponding ROIs, area under attenuation curve (AUC), and signal to noise ratio (SNR) of brain parenchyma were assessed. Subjective image quality was assessed on a 5-point scale by two blinded observers (1: excellent, 5: non-diagnostic). Radiation dose of ULD was more than six times lower compared to LD. SNR was improved by HYPR: ULD vs. ULD+HYPR: 1.9±0.3 vs. 8.4±1.7, LD vs. LD+HYPR: 5.0±0.7 vs. 13.4±2.4 (both p<0.0001). There was a good correlation between the original datasets and the HYPR-LR post-processed datasets: r = 0.848 for ULD and ULD+HYPR and r = 0.933 for LD and LD+HYPR (p<0.0001 for both). The mean values of the HYPR-LR post-processed ULD dataset correlated better with the standard LD dataset (r = 0.672) than unprocessed ULD (r = 0.542), but both correlations were significant (p<0.0001). There was no significant difference in AUC or MAX. Image quality was rated excellent (1.3) in LD+HYPR and non-diagnostic (5.0) in ULD. LD and ULD+HYPR images had moderate image quality (3.3 and 2.7). SNR and image quality of ULD-BPCT can be improved to a level similar to LD-BPCT when using HYPR-LR without distorting attenuation measurements. This can be used to substantially reduce radiation dose. Alternatively, LD images can be improved by HYPR-LR to higher diagnostic quality.

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• Comparison of selective arterial spin labeling using 1D and 2D tagging RF pulses.

  Authors: Simon Konstandin, Patrick M Heiler, Johann Scharf, Lothar R Schad

  Zeitschrift für medizinische Physik. 09/2010; 21(1):26-32.

  Generic arterial spin labeling (ASL) techniques label all brain feeding arteries. In this work, we used two different selective ASL (SASL) methods to show the perfusion of one single artery. A sliceGeneric arterial spin labeling (ASL) techniques label all brain feeding arteries. In this work, we used two different selective ASL (SASL) methods to show the perfusion of one single artery. A slice selective inversion of an area including the desired vessel was compared to a multidimensional RF pulse with Gaussian profile to label only the artery of interest. Perfusion images with a resolution of 2 x 2 x 5 mm(3) are shown that were acquired after tagging only the internal carotid artery of healthy volunteers. In addition, both techniques were applied to a patient with an extra-intracranial bypass to illustrate its perfusion territory. These perfusion images are consistent with a standard angiography. SASL imaging with a resolution of 2 x 2 x 5 mm(3) is possible in a total scan time of 5 min. The presented MR techniques may in part replace the assessment of revascularization success by conventional angiography.

• TrueFISP imaging of the pineal gland: more cysts and more abnormalities.

  Authors: Ingo Nolte, Marc A Brockmann, Lars Gerigk, Christoph Groden, Johann Scharf

  Clinical neurology and neurosurgery. 04/2010; 112(3):204-8.

  Although pineal cysts are found with a frequency of over one third in autopsy series, prevalences reported in standard magnetic resonance imaging (MRI) studies only range between 0.14% and 4.9%. WithAlthough pineal cysts are found with a frequency of over one third in autopsy series, prevalences reported in standard magnetic resonance imaging (MRI) studies only range between 0.14% and 4.9%. With the advances in scanner technology and more sensitive high-resolution 3D-sequences, pineal cysts with atypical appearance are more frequently encountered as an incidental finding. In order to help the radiologist and the clinician to correctly interpret these incidental findings and to avoid follow-up MRI or even surgical intervention, we analysed the frequency of typical and atypical pineal cysts using standard MRI-sequences and a high-resolution 3D-trueFISP-sequence (true-Fast-Imaging-with-Steady-State-Precession). In 111 patients undergoing MRI we analysed the prevalence of pineal cysts in relation to gender and age, as well as the frequency of atypical cysts defined by thickened rim, trabeculations, or asymmetric form using three standard MRI-sequences (T1-SE (T1 weighted spin echo), T2-TSE (T2 weighted turbo spin echo), FLAIR (fluid attenuated inversion recovery)) and compared the diagnostic certainty of these standard sequences with the sensitivity of a high-resolution trueFISP MRI sequence. Using trueFISP pineal cysts were detected more frequently than in the standard sequences (35.1% vs. 9.0% (T1-SE), 4.5% (T2-TSE) and 9.0% (FLAIR)). Diagnostic uncertainty was least frequent in trueFISP. In trueFISP, 41.0% of the detected cysts showed one or more features of atypical cysts (standard sequences: 21.4%). Highest prevalence of cysts was detected in the group of 20-30-year-old patients and decreased with increasing age. High-resolution 3D-sequences like trueFISP increase the detection rate of pineal cysts to levels reported in autoptic series while decreasing the diagnostic uncertainty. Atypically configurated pineal cysts are frequently detected as an incidental finding.

• In vitro labeling of glioma cells with gadofluorine M enhances T1 visibility without affecting glioma cell growth or motility.

  Authors: Ingo S Nolte, Sevil Gungor, Ralf Erber, Elena Plaxina, Johann Scharf, Bernd Misselwitz, Lars Gerigk, Heike Przybilla, Christoph Groden, Marc A Brockmann

  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. 06/2008; 59(5):1014-20.

  Gadofluorine is a novel macrocyclic, amphiphilic gadolinium-based contrast agent. We found that malignant glioma cells could be labeled in vitro using Gadofluorine without the need for transfectionGadofluorine is a novel macrocyclic, amphiphilic gadolinium-based contrast agent. We found that malignant glioma cells could be labeled in vitro using Gadofluorine without the need for transfection agents or any other additional means. Labeling with Gadofluorine enhanced the visualization of glioma cells in T(1)-weighted sequences, even if the cells had been cultured in medium without Gadofluorine over several days. The intracellular uptake of Gadofluorine was measured and the loss of relevant amounts of Gadofluorine into the cell culture medium was ruled out by MRI. Confocal laser fluorescence microscopy revealed Cy-5-labeled Gadofluorine in the perinuclear cytoplasmic region, but neither within the nucleus nor bound to the cell membrane. Adverse effects of cellular Gadofluorine uptake were ruled out by proliferation and migration assays. Finally, in vivo analyses provided good visibility of labeled glioma cells in T(1)-weighted sequences after intracerebral injection in mice for more than 2 weeks. We thus conclude that Gadofluorine can easily be used to label glioma cells in vitro without affecting glioma cell biology. Gadofluorine provides an interesting alternative for cellular labeling if iron oxide particles are incorporated insufficiently by target cells or if the vicinity of susceptibility artifacts prohibits the use of signal-decreasing contrast agents.

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• Risk of intraoperative ischemia due to temporary vessel occlusion during standard extracranial-intracranial arterial bypass surgery.

  Authors: Peter Horn, Johann Scharf, Pablo Peña-Tapia, Peter Vajkoczy

  Journal of neurosurgery. 04/2008; 108(3):464-9.

  OBJECT: Standard extracranial-intracranial (EC-IC) arterial bypass surgery represents a well-recognized procedure in which the aim is to augment distal cerebral circulation. The creation of theOBJECT: Standard extracranial-intracranial (EC-IC) arterial bypass surgery represents a well-recognized procedure in which the aim is to augment distal cerebral circulation. The creation of the bypass requires temporary occlusion of the recipient vessel. Thus, there exists controversy about the risk of standard EC-IC arterial bypass surgery causing ischemic complications due to temporary vessel occlusion. In this prospective study, the incidence of intraoperative ischemia was investigated in symptomatic patients with steno-occlusive cerebrovascular disease and existing hemodynamic insufficiency. METHODS: Twenty consecutive patients (14 women and 6 men; mean age 46 +/- 11 years) suffering from recurrent transient ischemic attacks due to occlusive cerebrovascular disease and proven hemodynamic compromise in functional blood flow studies were enrolled in this study. The underlying pathological condition was internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion in 6 cases and ICA or MCA stenosis in 3 cases, whereas 11 patients presented with moyamoya syndrome or moyamoya disease. The surgical procedure consisted of the establishment of a standard superficial temporal artery (STA)-MCA bypass, and was performed while a strict intraoperative management protocol was applied. Patients underwent clinical examination and magnetic resonance (MR) imaging within 48 hours before and after surgery. RESULTS: The incidence of reversible clinical signs of ischemia was 2 (10%) of 20 patients. Postoperative MR imaging revealed signs of diffusion disturbances in 2 (10%) of 20 cases. The observed diffusion-weighted imaging changes, however, were situated within the dependent vascular territory at risk for ischemia in 1 patient only. No permanent neurological deficit occurred. The temporary vessel occlusion time ranged between 25 and 42 minutes (mean 33 +/- 7 minutes). All means are expressed +/- the standard deviation. CONCLUSIONS: Temporary vessel occlusion during standard STA-MCA arterial bypass surgery carries a low risk of intraoperative ischemia when a strict perioperative management protocol is applied.

• A diagnostic pitfall for intracranial aneurysms in time-of-flight MR angiography: small intracranial lipomas.

  Authors: Andre Kemmling, Ingo Noelte, Lars Gerigk, Stephan Singer, Christoph Groden, Johann Scharf

  AJR. American journal of roentgenology. 02/2008; 190(1):W62-7.

  OBJECTIVE: The sensitivity of MR angiography (MRA) for aneurysms smaller than 3 mm in diameter is limited. Diagnostic pitfalls may arise from primary T1 hyperintense lesions on time-of-flight (TOF)OBJECTIVE: The sensitivity of MR angiography (MRA) for aneurysms smaller than 3 mm in diameter is limited. Diagnostic pitfalls may arise from primary T1 hyperintense lesions on time-of-flight (TOF) imaging adjacent to a vessel. Independently, three patients were referred from outside facilities for diagnostic workup of suspected aneurysms of the vertebrobasilar system on TOF images. The lesions were identified as small lipomas, which prompted us to systematically analyze characteristics of intracranial lipomas on TOF images. MATERIALS AND METHODS: From our local database, 38,000 cranial MRI scans were searched for intracranial lipomas. If available, TOF images of identified lipomas were analyzed. In addition, in vitro MRI of excised cadaveric lipomas and other fatty specimens were examined for characteristics on TOF images and the presence of chemical shift artifacts. RESULTS: Seventeen intracranial lipomas (0.045%) were identified. Out-of-phase TOF source images available in 12 identified lipomas showed a continuous dark peripheral fringe and a hyperintense center. In vitro out-of-phase chemical shift images of excised cadaveric lipomas revealed the same consistent fringe artifact, known as "india ink," independent of size, shape, surrounding fibrous capsule, or texture of the fatty specimen. In contrast, in-phase chemical shift artifact was variable. CONCLUSION: Small intracranial lipomas close to a cerebral artery are hyperintense on TOF MR images and could be mistaken for partially thrombosed aneurysms and associated flow-related artifact. A defining characteristic of lipomas on TOF source images results from the out-of-phase india ink artifact. This dark fringe in the periphery of the lesions is characteristic and helps avoid potential diagnostic pitfalls.

• Assessment of hepatic perfusion in transplanted livers by pharmacokinetic analysis of dynamic magnetic resonance measurements.

  Authors: Johann Scharf, Andre Kemmling, Thomas Hess, Arianeb Mehrabi, Guenter Kauffmann, Christoph Groden, Gunnar Brix

  Investigative radiology. 05/2007; 42(4):224-9.

  OBJECTIVE: The purpose of this study was to validate the assessment of hepatic perfusion by pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance image series. MATERIALS ANDOBJECTIVE: The purpose of this study was to validate the assessment of hepatic perfusion by pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance image series. MATERIALS AND METHODS: Dynamic measurements were performed with a saturation recovery turbo fast low angle shot (ie, FLASH) sequence over the course of approximately 4 minutes in 17 patients with transplanted livers. By pharmacokinetic analysis using an open 2-compartment model, we estimated and correlated an amplitude of signal enhancement, A, and the perfusion rate, kp, with invasive perfusion measurements from implanted thermo-diffusion probes (FTDP). RESULTS: Data analysis for segment IV of the transplanted livers yielded a mean blood flow of 81 +/- 19 mL/min/100g and a mean perfusion rate of 13 +/- 6 minutes. There was a significant correlation between FTDP and kp (rS = 0.64, P = 0.01) but not with A. CONCLUSIONS: Although our open 2-compartment model oversimplifies the complexity of hepatic perfusion, it allows a numerically robust estimation of regional blood flow per unit of blood volume. Thus, dynamic magnetic resonance imaging represents a noninvasive method to assess hepatic perfusion rate which can be visualized in color coded images.

• Spontaneous recanalization of occluded standard extracranial-intracranial arterial bypass.

  Authors: Johann Scharf, Peter Schmiedek, Andre Kemmling, Lars Gerigk, Christoph Groden, Peter Horn

  Cerebrovascular diseases (Basel, Switzerland). 02/2007; 23(2-3):175-80.

  BACKGROUND: In the event of early failure of standard extracranial-intracranial arterial bypass, elective but prompt revision surgery is generally attempted under the assumption that early occlusionBACKGROUND: In the event of early failure of standard extracranial-intracranial arterial bypass, elective but prompt revision surgery is generally attempted under the assumption that early occlusion is permanent. However, little is known about the occurrence of spontaneous revascularization. OBJECTIVE: To estimate the frequency and time course of spontaneous recanalization in primary extracranial-intracranial arterial bypass occlusion and re-evaluate diagnostic and therapeutic options facing spontaneous development. METHODS AND RESULTS: In a retrospective analysis 176 patients with standard superficial temporal artery/middle cerebral artery bypass were included. Twenty-three patients had primary bypass occlusion. In 7 cases spontaneous recanalization was observed. Follow-up of these cases is presented. CONCLUSIONS: Early bypass occlusion has a high incidence of spontaneous recanalization within the first year. In stable patients the first choice may be noninvasive follow-up and postponing revision operation.

• Outcome after lumbar sequestrectomy compared with microdiscectomy: a prospective randomized study.

  Authors: Claudius Thomé, Martin Barth, Johann Scharf, Peter Schmiedek

  Journal of neurosurgery. Spine. 04/2005; 2(3):271-8.

  OBJECT: Microdiscectomy currently constitutes the standard treatment for herniated lumbar discs. Although limiting surgery to excision of fragments has occasionally been suggested, prospective dataOBJECT: Microdiscectomy currently constitutes the standard treatment for herniated lumbar discs. Although limiting surgery to excision of fragments has occasionally been suggested, prospective data are lacking. Therefore, the objective of this study was to compare early outcome and recurrence rates after sequestrectomy and microdiscectomy. METHODS: Eighty-four consecutive patients 60 years of age or younger who harbored free, subligamentary, or transanular herniated lumbar discs refractory to conservative treatment were randomized to one of two treatment groups. Intraoperative parameters and findings were documented as well as pre- and postoperative symptoms such as pain, Patient Satisfaction Index (PSI), Prolo Scale score, and Short Form (SF)-36 subscale results. Follow up of at least 12 months was available in 73 patients (87%). Preoperative intergroup symptoms did not differ significantly. Surgery was significantly shorter in the sequestrectomy-treated group. Overall, low-back pain and sciatica were drastically reduced in both groups and most sensorimotor deficits improved. At 4 to 6 months, SF-36 subscales and PSI scores showed a trend in favor of sequestrectomy, leaving 3% of patients unsatisfied compared with 18% of those treated with discectomy. Outcome according to the Prolo Scale was good or excellent in 76% of discectomy-treated patients and 92% of sequestrectomy-treated patients. Reherniation occurred in four patients after discectomy (10%) and two patients after sequestrectomy (5%) within 18 months. CONCLUSIONS: Sequestrectomy does not seem to entail a higher rate of early recurrences compared with microdiscectomy. Analysis of early outcome demonstrated a trend toward superior results when sequestrectomy is performed. Although long-term follow-up data are mandatory, sequestrectomy may be an advantageous alternative to standard microdiscectomy.

• Cerebral sinus thrombosis in a trauma patient after recombinant activated factor VII infusion.

  Authors: Leonie J Siegel, Lars Gerigk, Jochen Tuettenberg, Carl-Erik Dempfle, Johann Scharf, Fritz Fiedler

  Anesthesiology. 03/2004; 100(2):441-3.

• Comparison of selective arterial spin labeling using 1D and 2D tagging RF pulses

  Authors: Simon Konstandin, Patrick M. Heiler, Johann Scharf, Lothar R. Schad

  Zeitschrift für Medizinische Physik.

  Generic arterial spin labeling (ASL) techniques label all brain feeding arteries. In this work, we used two different selective ASL (SASL) methods to show the perfusion of one single artery. A sliceGeneric arterial spin labeling (ASL) techniques label all brain feeding arteries. In this work, we used two different selective ASL (SASL) methods to show the perfusion of one single artery. A slice selective inversion of an area including the desired vessel was compared to a multidimensional RF pulse with Gaussian profile to label only the artery of interest. Perfusion images with a resolution of 2 x 2 x 5 mm3 are shown that were acquired after tagging only the internal carotid artery of healthy volunteers. In addition, both techniques were applied to a patient with an extra-intracranial bypass to illustrate its perfusion territory. These perfusion images are consistent with a standard angiography. SASL imaging with a resolution of 2 x 2 x 5 mm3 is possible in a total scan time of 5 min. The presented MR techniques may in part replace the assessment of revascularization success by conventional angiography.ZusammenfassungIn der klinischen Routine tragen bei der “Arterial-Spin-Labeling”-Methode üblicherweise alle hirnversorgenden Arterien zur gemessenen Hirnperfusion bei. In dieser Arbeit werden zwei verschiedene Ansätze verwendet, um selektiv einzelne Arterien zu markieren. Eine schicht-selektive Inversion einer Region, in der sich bestenfalls nur die erwünschte Arterie befindet, wird mit einem mehrdimensionalen, gaußförmigen Markierungspuls verglichen. Es werden Perfusionsmessungen mit einer Auflösung von 2 x 2 x 5 mm3 gezeigt, wobei die innere Karotisarterie gesunder Probanden markiert wurde. Außerdem wurden beide Techniken an einem Patienten mit extra-intrakraniellem Bypass angewandt, um dessen Perfusionsgebiete zu bestimmen. Diese Ergebnisse stimmten sehr gut mit einer Standard-Angiographie überein. Es wird gezeigt, dass eine Auflösung von 2 x 2 x 5 mm3 in einer Messzeit von 5 Minuten erreicht werden kann und dass die hier gezeigten Techniken in Zukunft teilweise die gewöhnliche Angiographie ersetzen könnten.

• Improvement of sensitivity and interrater reliability to detect acute stroke by dynamic perfusion computed tomography and computed tomography angiography.

  Authors: Johann Scharf, Marc A Brockmann, Michael Daffertshofer, Michael Diepers, Eva Neumaier-Probst, Christel Weiss, Tilmann Paschke, Christoph Groden

  Journal of computer assisted tomography. 30(1):105-10.

  OBJECTIVE: To assess the benefits of additional computed tomography perfusion (CTP) and computed tomography angiography (CTA) on the detection of early stroke, vessel occlusion, estimated infarctOBJECTIVE: To assess the benefits of additional computed tomography perfusion (CTP) and computed tomography angiography (CTA) on the detection of early stroke, vessel occlusion, estimated infarct size, and interrater reliability. METHODS: Sixty-seven consecutive patients underwent nonenhanced computed tomography (CT) imaging, CTA, and CTP. The final diagnosis of stroke was made from follow-up neuroimaging. A first diagnosis was made on-site by the physician on duty. Three experienced neuroradiologists blinded to follow-up findings analyzed the data set off-line, evaluated CT for signs of acute stroke, and subsequently evaluated CTP and CTA for infarction-related perfusion deficits and vessel abnormalities. RESULTS: Computed tomography perfusion and CTA increased the time from CT start to diagnosis from 2 minutes to 10 minutes. Sensitivity to detect acute stroke increased significantly in all investigators from 0.46-0.58 to 0.79-0.90 compared with CT (<0.005). The interrater weighted kappa value increased from 0.35 to 0.64. Estimation of infarct size was not improved. CONCLUSION: Computed tomography perfusion and CTA provide an effective add-on to standard CT in acute stroke imaging by significantly increasing the sensitivity and reliability of infarct detection.

• Letter to Editor - Complex spontaneous extracranial-intracranial collateralization in progressive systemic atherosclerotic disease

  Authors: Peter Horn, Johann Scharf, Peter Schmiedek

  Neurology India (ISSN: 0028-3886) Vol 55 Num 4.

• Complex spontaneous extracranial-intracranial collateralization in progressive systemic atherosclerotic disease.

  Authors: Peter Horn, Johann Scharf, Peter Schmiedek

  Neurology India. 55(4):432-3.