Biomedical subjects

Michael Mull

Publications and source records attributed to Michael Mull.

10 recordsLinked to original sources

PubMed2006

The hyperdense posterior cerebral artery sign: a computed tomography marker of acute ischemia in the posterior cerebral artery territory.

BACKGROUND AND PURPOSE: In the anterior circulation, the hyperdense middle cerebral artery (MCA) sign is a well-established marker for early ischemia. Similarly, the hyperdense basilar artery sign or the MCA "dot" sign may be a diagnostic clue for basilar artery or distal MCA branch thrombosis. The purpose of this study was to define the hyperdense posterior cerebral artery (PCA) sign and determine its incidence, diagnostic value, and reliability as a marker for ischemia in the territory of the PCA. METHODS: Cranial computed tomographies (CCTs) of 48 patients with proven acute ischemia (<12 hours) in the PCA territory were compared by 3 independent and blinded readers to the CCTs of 86 age-matched patients without PCA infarction. Using follow-up imaging, the correlation of the hyperdense PCA (HPCA) with infarct size, thalamic infarction, and bleeding were investigated. RESULTS: An HPCA was found in 35.4% of all patients with PCA infarction, typically within the ambient cistern, with a specificity of 95.4%. The thalamus was affected significantly more often (P=0.009) and the size of the infarct was significantly more often large than medium (P=0.018) or small (P<0.001) when an HPCA was present. Hemorrhagic transformation tended to occur more often when the HPCA was present. CONCLUSIONS: An HPCA was detected in more than one third of all patients with PCA ischemia, suiting the incidence of the hyperdense MCA. Based on our results, this sign may not only be helpful in the early diagnosis of PCA infarction but might also act as a prognostic marker in acute PCA territory ischemic stroke.

Adult↗

PubMed2006

Basilar megadolicho trunk causing obstructive hydrocephalus at the foramina of Monro.

We report on a 54-year-old man with megadolicho basilar artery presenting with acute signs of raised intracranial pressure due to a compromise of cerebrospinal fluid (CSF) flow at the level of the foramina of Monro by the basilar apex extending more than 3 cm cranially to the dorsum sellae. The diagnosis was confirmed on computed tomographic angiography and emergent CSF drainage relieved symptoms immediately.

Basilar Artery↗

PubMed2006

Spinal dural arteriovenous fistula associated with a spinal perimedullary fistula: case report.

Among spinal cord vascular malformations, dural arteriovenous fistulas (DAVFs) must be distinguished from intradural malformations. The concurrence of both is extremely rare. The authors report the case of a 35-year-old man who suffered from progressive myelopathy and who harbored both a DAVF and an intradural perimedullary fistula. During surgery, both fistulas were identified, confirmed, and subsequently obliterated. The fistulas were located at two levels directly adjacent to each other. Although the incidence of concurrent spinal DAVFs is presumed to be approximately 2%, the combination of a dural and an intradural fistula is exceedingly rare; only two other cases have been reported in the literature. One can speculate whether the alteration in venous drainage caused by the (presumably congenital) perimedullary fistula could possibly promote the production of a second dural fistula due to elevated pressure with concomitant venous stagnation and subsequent thrombosis. The authors conclude that despite the rarity of dual pathological entities, the clinician should be aware of the possibility of the concurrence of more than one spinal fistula in the same patient.

Adult↗

PubMed2006

Spinal epidural arteriovenous fistula with perimedullary drainage. Case report and pathomechanical considerations.

The classic angiographically demonstrated features of spinal dural arteriovenous fistulas are shunts of radiculomeningeal branches with radicular veins draining exclusively in the direction of perimedullary veins and thereby causing venous congestion. These shunts are located at the point where the radicular vein passes the dura mater. Spinal epidural arteriovenous shunts, however, normally do not drain into the perimedullary veins and are, therefore, asymptomatic, presumably because of a postulated reflux-impeding mechanism between the dural sleeves. The authors report on a patient in whom an epidural arteriovenous shunt showed delayed retrograde drainage into perimedullary veins, leading to the classic clinical (and magnetic resonance imaging-based) findings of venous congestion. Intraoperatively the angiographically established diagnosis was confirmed. Coagulation of both the epidural shunt zone and the radicular vein resulted in complete obliteration of the fistula, as confirmed on repeated angiography. This rare type of fistula should stimulate considerations on the role of valvelike mechanisms normally impeding retrograde flow from the epidural plexus to perimedullary veins and suggest that, in certain pathological circumstances, epidural fistulas can drain retrogradely into perimedullary veins as an infrequent variant of spinal arteriovenous shunts.

Aged↗

PubMed2004

Do normal D-dimer levels reliably exclude cerebral sinus thrombosis?

BACKGROUND AND PURPOSE: Cerebral sinus thrombosis (CST) needs to be considered in the differential diagnosis of all patients with acute headache. Early diagnosis is essential because early treatment may prevent morbidity and may even be life-saving. Definite exclusion, however, needs advanced neuroradiologic diagnostics, which are not readily available in many hospitals. Because measurement of D-dimers has been demonstrated to be helpful in excluding thromboembolic disease, our aim was to investigate whether D-dimers would be also sensitive enough to exclude CST. METHODS: We undertook a prospective multicenter study over a 2.5-year period including all patients who came to the emergency departments with symptoms suggestive of CST. All patients were diagnosed either by magnetic resonance venography, spiral computed tomography scan venography, or intra-arterial digital subtraction angiography. D-dimer levels were measured at admission and analyzed by the same method in all patients. RESULTS: A total of 343 patients were included. CST was diagnosed in 35 patients, of whom 34 had D-dimers above the cutoff value (>500 microg/L). From the 308 patients not having CST, D-dimers were elevated in 27. Sensitivity of D-dimers was 97.1%, with a negative predictive value of 99.6%. Specificity was 91.2%, with a positive predictive value of 55.7%. D-dimers were positively correlated with the extent of the thrombosis and negatively correlated with the duration of symptoms (Spearman rank correlation coefficients 0.76, -0.58, respectively). CONCLUSIONS: D-dimer measurement is useful in patients with suspected CST. Normal D-dimers make the presence of CST very unlikely.

Adult↗

PubMed2004

Spinal vascular malformations.

Spinal vascular malformations are rare diseases that consist of true inborn cavernomas and arteriovenous malformations (including perimedullary fistulae, glomerular and juvenile AVMs) and presumably acquired dural arteriovenous fistulae. This review article gives an overview of the imaging features both on MRI and angiography, the differential diagnoses, the clinical symptomatology and the potential therapeutic approaches to these diseases. It is concluded that MRI is the diagnostic modality of first choice in suspected spinal vascular malformation and should be complemented by selective spinal angiography. Treatment in symptomatic patients offers an improvement in the prognosis, but should be performed in specialized centers. Patients with spinal cord cavernomas and perimedullary fistulae type I are surgical candidates. Dural arteriovenous fistulae can either be operated upon or can be treated by an endovascular approach, the former being a simple, quick and secure approach to obliterate the fistula, while the latter is technically demanding. In spinal arteriovenous malformations, the endovascular approach is the method of first choice; in selected cases, a combined therapy might be sensible.

Angiography↗

PubMed2004

Three-dimensional assessment of extracranial Doppler sonography in carotid artery stenosis compared with digital subtraction angiography.

BACKGROUND AND PURPOSE: Difficulties in data presentation, data storage, and a high interobserver variability may influence color-coded Duplex sonography assessment of internal carotid artery stenosis (ICAS). The aim of our study was to evaluate the between-method agreement of ICAS using 3D color Doppler sonography (CDS) compared with digital subtraction angiography (DSA). METHODS: Forty-nine patients with 64 ICASs (age 64+/-9 years) were involved. The patients were investigated with a color-coded duplex system using the power mode. The 3D system consists of an electromagnet that induces a low-intensity magnetic field near the patient's head. A magnetic position sensor is attached to the probe and transmits the spatial orientation to a personal computer. RESULTS: A total of 62 ICASs were reconstructed successfully with 3D CDS in 47 of 49 patients. High agreement for 2 independent observers was found in 3D CDS (weighted kappa coefficient of 0.88). Three-dimensional CDS slightly underestimated the mean stenotic degree (mean 3D CDS 68.47+/-10.5 versus DSA 71.3+/-10.0). The intermethod agreement comparing DSA with 3D CDS was analyzed with the Bland and Altman test, which showed good agreement. Mean sensitivity of 3D CDS was 93%, mean specificity 82.5%, mean positive predictive value 82%, and mean negative predictive value 98%. CONCLUSIONS: The 3D CDS findings demonstrated good agreement compared with the gold standard, DSA, yielding higher accuracy than CDS alone. Compared with angiography or magnetic resonance angiography, 3D CDS can be performed easily on critically ill patients in stroke or intensive care units and may therefore provide a useful tool for patients unable to undergo more invasive imaging techniques.

Aged↗

PubMed2004

Intracranial collateral pathways assessed by contrast-enhanced three-dimensional transcranial color-coded sonography.

Individual parameter settings of the duplex machine and limited insonation angles may influence the visualization of small intracranial vessels in 2-D transcranial color-coded sonography. The aim of our study was the morphologic assessment of intracranial collateral pathways (first auditory area celiac artery, A(1)CA; anterior communicating artery, AComA; first parental generation celiac artery P(1)CA; posterior communicating artery, PComA) using 3-D transcranial color-coded duplex sonography (3-D TCCS) and digital subtraction angiography (DSA). A total of 41 patients with large vessel disease and 30 patients who had suffered subarachnoidal hemorrhage (mean age 52 +/- 15 years) were involved. In all patients, angiography was performed within 10 days following 3-D sonography. The patients were investigated with a color-coded duplex system using the power mode. Contrast enhancement was achieved by continuous infusion of a galactose-based echo-enhancer using a perfusor pump. The 3-D system consists of an electromagnet that induces a low-intensity magnetic field near the head of the patient. A magnetic position sensor is attached to the ultrasound (US) probe and transmits the spatial orientation to a personal computer, which also receives the corresponding 2-D images from the video port of the duplex machine. Angiography revealed a "complete" circle of Willis in one third of the patients and, in the remaining patients at least one vessel was hypoplastic or absent. Sufficient temporal bone windows allowed the sonographic investigation of 466 (94%) of 497 expected arterial segments. The comparison of both techniques resulted in a weighted kappa value of 0.56 for the A(1)CA and 0.63 for the AComA. In the posterior circulation kappa values of 0.56 for the P(1)CA and 0.43 for the PComA were calculated. In 50 vessels (10%), 3-D sonography misdiagnosed the diameter of a collateral vessel as normal and angiography revealed hypoplasia or aplasia of this vessel. The main advantage of 3-D TCCS is that it enables the investigator to reconstruct virtually any arbitrary view angle. Compared with angiography or magnetic resonance (MR) angiography, 3-D sonography can be performed easily in critically ill patients on stroke units or intensive care units. The noninvasive assessment of the circle of Willis may be useful in patients who undergo carotid surgery without angiography. Combined with hemodynamic information, contrast-enhanced 3-D TCCS might increase the diagnostic impact of transcranial US.

Angiography, Digital Subtraction↗

PubMed2003

Oligophrenin 1 (OPHN1) gene mutation causes syndromic X-linked mental retardation with epilepsy, rostral ventricular enlargement and cerebellar hypoplasia.

We identified an oligophrenin 1 (OPHN1) gene mutation in a family with five brothers affected by a recognizable pattern of clinical and neuroradiological hallmarks. The distinctive phenotype comprised moderate to severe mental retardation, myoclonic-astatic epilepsy, ataxia, strabismus and hypogenitalism. Neuroimaging displayed fronto-temporal atrophy with rostral enlargement of the lateral ventricles, lower vermian agenesis and asymmetric cerebellar hypoplasia. Mutation analysis of the OPHN1 gene on Xq12 disclosed a genomic deletion of exon 19 causing a frameshift. Notably, OPHN1 mutations have been previously reported as a rare cause of non-syndromic X-linked mental retardation. Our findings, however, indicate that OPHN1 mutations result in a recognizable syndrome. In addition, identification of OPHN1 as a further gene associated with epileptic seizures will help to unravel aetiologic factors of epilepsy.

Base Sequence↗

PubMed2002

Contrast-enhanced three-dimensional transcranial color-coded sonography of intracranial stenoses.

BACKGROUND AND PURPOSE: Intracranial stenoses are associated with a considerable number of strokes each year. The clinical value of a workstation-based three-dimensional (3D) reconstruction system for transcranial color-coded sonography was evaluated in patients with intracranial stenosis or occlusion. METHODS: Twenty-six patients (13 men, 13 women; mean age, 57 years +/- 12 [SD]) with 36 intracranial stenoses or occlusions, as detected at two-dimensional (2D) color Doppler imaging (CDI) and digital subtraction angiography (DSA), underwent Levovist-enhanced power Doppler imaging (PDI), with subsequent 3D reconstruction. A workstation connected to a magnetic sensor capable of spatial localization of the probe was used to reconstruct 3D images of the circle of Willis from serial PDI images. RESULTS: At DSA, seven (19%) stenoses were estimated to less than 50%, 24 (67%) were 50% or more, and five (14%) were occluded. DSA and 3D-PDI estimates of the degree of stenosis agreed in 33 cases (92%), with a weighted kappa value of 0.86. Disagreement occurred with two subtotal basilar artery stenoses and one subtotal middle cerebral artery stenosis, which were evaluated as being complete occlusions at 3D-PDI. Interobserver agreement between two experienced 3D investigators in estimating the percentage of stenosis was high (correlation coefficient,.98). CONCLUSION: 3D-PDI enables the investigator to reconstruct virtually any arbitrary viewing angle. Compared with conventional CDI, 3D-PDI offers easier spatial assessment of intracranial stenoses, and its findings are sufficiently correlated with angiographic findings. Because different investigators can postprocess the same 3D data, improving reproducibility and reducing investigator dependency in transcranial color-coded sonography may be possible.

Aged↗