Relationship between 'on-treatment platelet reactivity', shear stress, and micro-embolic signals in asymptomatic and symptomatic carotid stenosis.

BACKGROUND: Assessment of 'high on-treatment platelet reactivity (HTPR)' could enhance understanding of the pathophysiology of first or recurrent vascular events in carotid stenosis patients on antiplatelet therapy. METHODS: This prospective, multi-centre study assessed antiplatelet-HTPR status and its relationship with micro-emboli signals (MES) in asymptomatic vs. symptomatic ≥ 50-99% carotid stenosis. Platelet function/reactivity was assessed under 'moderately high shear stress' with the PFA-100® and 'low shear stress' with VerifyNow® and Multiplate® analysers. Bilateral 1-h transcranial Doppler ultrasound of the middle cerebral arteries classified patients as MES + ve or MES - ve. RESULTS: Data from 34 asymptomatic patients were compared with 43 symptomatic patients in the 'early phase' (≤ 4 weeks) and 37 patients in the 'late phase' (≥ 3 months) after TIA/ischaemic stroke. Median daily aspirin doses were higher in early symptomatic (225 mg; P < 0.001), but not late symptomatic (75 mg; P = 0.62) vs. asymptomatic patients (75 mg). There was a lower prevalence of aspirin-HTPR in early (28.6%; P = 0.028), but not late symptomatic (38.9%; P = 0.22) compared with asymptomatic patients (56.7%) on the PFA-100®, but not on the VerifyNow® or Multiplate® (P ≤ 0.53). Early symptomatic patients had a higher prevalence of aspirin-HTPR on the PFA-100® (28.6%) vs. VerifyNow® (9.5%; P = 0.049), but not Multiplate® assays (11.9%, P = 0.10). There was no difference in aspirin-HTPR prevalence between any symptomatic vs. asymptomatic MES + ve or MES - ve subgroup. DISCUSSION: Recently symptomatic moderate-severe carotid stenosis patients had a lower prevalence of aspirin-HTPR than their asymptomatic counterparts on the PFA-100®, likely related to higher aspirin doses. The prevalence of antiplatelet-HTPR was positively influenced by higher shear stress levels, but not MES status.

Portal Hypertensive Colopathy with Pelvic Varices presenting as Severe Lower GI Bleed treated with TIPSS.

We present the case of a 71-year-old lady with a background of significant alcohol intake who presented with frank lower gastrointestinal (GI) bleeding, lower abdominal pain and haemoglobin 6.3g/dL. CT abdominal angiogram showed right-sided colonic thickening, atrophic liver and enlarged superior mesenteric vein (SMV) and right-sided pelvic varix. This lead to a diagnosis of portal hypertensive colopathy secondary to alcoholic liver cirrhosis. The patient failed conservative management and underwent a Transjugular Intrahepatic Portosystemic Shunt (TIPSS) procedure. This lead to an immediate resolution of her lower-GI bleeding. Repeat CT at three weeks showed a decompressed SMV and resolution of the right-sided pelvic varix. The patient was discharged after three months following optimization of medical condition and social circumstances.

Effectiveness of a low support, remotely accessible, cognitive remediation training programme for chronic psychosis: cognitive, functional and cortical outcomes from a single blind randomised controlled trial.

BACKGROUND: Cognitive remediation (CR) training has emerged as a promising approach to improving cognitive deficits in schizophrenia and related psychosis. The limited availability of psychological services for psychosis is a major barrier to accessing this intervention however. This study investigated the effectiveness of a low support, remotely accessible, computerised working memory (WM) training programme in patients with psychosis. METHODS: Ninety patients were enrolled into a single blind randomised controlled trial of CR. Effectiveness of the intervention was assessed in terms of neuropsychological performance, social and occupational function, and functional MRI 2 weeks post-intervention, with neuropsychological and social function again assessed 3-6 months post-treatment. RESULTS: Patients who completed the intervention showed significant gains in both neuropsychological function (measured using both untrained WM and episodic task performance, and a measure of performance IQ), and social function at both 2-week follow-up and 3-6-month follow-up timepoints. Furthermore, patients who completed MRI scanning showed improved resting state functional connectivity relative to patients in the placebo condition. CONCLUSIONS: CR training has already been shown to improve cognitive and social function in patient with psychosis. This study demonstrates that, at least for some chronic but stable outpatients, a low support treatment was associated with gains that were comparable with those reported for CR delivered entirely on a 1:1 basis. We conclude that CR has potential to be delivered even in services in which psychological supports for patients with psychosis are limited.

Horizontal nystagmus and multiple sclerosis using 3-Tesla magnetic resonance imaging.

BACKGROUND: Nystagmus in patients with multiple sclerosis (MS) is generally attributed to brainstem disease. Lesions in other regions may result in nystagmus. The identification of these other sites is enhanced by using 3-Tesla magnetic resonance imaging (3TMRI) due to increased signal-to-noise ratio. OBJECTIVE: We sought to evaluate the distribution of structural lesions and disruption of tracts in patients with horizontal nystagmus secondary to MS using 3TMRI. METHODS: Twenty-four patients (20 women, 4 men; age range 26-55 years) with horizontal nystagmus secondary to MS underwent 3TMRI brain scans; and 18 patients had diffusion tensor imaging (DTI) for tractography. RESULTS: Nystagmus was bidirectional in 11, right-sided in 6 and left-sided in 7. We identified 194 lesions in 20 regions within the neural integrator circuit in 24 patients; 140 were within the cortex and 54 were within the brainstem. Only two patients had no lesions in the cortex, and 9 had no lesions in the brainstem. There was no relationship between side of lesion and direction of nystagmus. Thirteen of 18 (72 %) had tract disruption with fractional anisotropy (FA) values below 0.2. FA was significantly lower in bidirectional compared to unidirectional nystagmus (p = 0.006). CONCLUSION: In MS patients with horizontal nystagmus, lesions in all cortical eye fields and their descending connections were evident. Technical improvements in tractography may help identify the specific site(s) resulting in nystagmus in MS.

Ischaemic stroke or TIA in older subjects associated with impaired dynamic blood pressure control in the absence of severe large artery stenosis.

BACKGROUND: older subjects may require higher baseline blood pressures to maintain cerebral perfusion. We investigated whether episodic hypotension is associated with tissue infarction in subjects with syncopal symptoms at stroke onset. METHODS: over 30 months, all acute strokes/TIAs were prospectively screened for symptoms of syncope or presyncope at stroke onset. Subjects with severe large vessel stenosis were excluded, while cases were referred for syncope unit investigation. All underwent 1.5 T MRI acutely, and suspected borderzone infarctions (BZI) were confirmed through Matlab-derived perfusion software. Case-control comparison was derived from stroke controls with no prior syncope history. RESULTS: thirty-eight of 772 stroke patients described presyncope or syncope at stroke onset and had patent large vessels (4.9% of all strokes). Median age was 72 years (IQR 21.4). Twenty-two patients (58%) were prescribed antihypertensive agents at symptom onset. Twenty-six (68.4%) reported focal neurology <24 h in duration. 63.2% (n = 24) of cases reported prior syncope history, compared with 33% (N = 103) of controls, P < 0.001. Cases exhibited greater orthostatic BP drop than controls, P < 0.05 Twenty-four patients were diagnosed with vasovagal syncope through head-up tilt symptom reproduction, 9 with orthostatic hypotension, 4 with cardiac syncope and 1 with carotid sinus syndrome. Nineteen (50%) patients had an acute infarct on MRI, 14 of these were in the arterial borderzone (73.6%). The BZI group were significantly older than the non-BZI group, 79.2 yrs versus 63.3 yrs, P = 0.002. CONCLUSION: subjects reporting hypotensive symptoms at stroke onset have a higher prevalence of borderzone infarction, despite being normotensive or hypertensive at baseline.

Syncope causes transient focal neurological symptoms.

AIMS: The prevalence of focal neurology (FN) as a consequence of syncope is unknown. The aim of the study was to determine its prevalence, risk factors and short-term consequences. METHODS: A consecutive sample of syncope-unit attendees during a 9-month period had detailed diagnostic syncope evaluation as per European Cardiac Society guidelines coupled with assessment for FN present during syncope/pre-syncope by screening questionnaire, follow-up interview and neuroimaging (1.5T magnetic resonance imaging [MRI]). All participants were followed up for 24 months. Risk factors for FN were identified by comparing FN cases with syncope controls without FN (3:1 ratio). RESULTS: Five-hundred and forty consecutively attended for investigation of syncope (n = 401) and pre-syncope (n = 139). Thirty-one (5.7%) had FN events during hypotensive symptoms, mean age 49 years (19-85). The majority of FN cases had vasovagal syncope (VVS); 22 (71%), whereas eight had OH (25.8%) and one (3.2%) had cardiac arrhythmia. Median duration of FN was 15 min (IQR: 34.5). MRI in 28 (90%) was normal and in 3, old cerebral infarction was evident. Risk factors for FN/syncope were frequent syncope (P = 0·008), childhood syncope (P < 0.0005) and delayed diastolic recovery during active stand (P = 0·02). During 24-month follow-up and targeted intervention, no patients developed recurrence of FN. CONCLUSION: One in 20 patients with syncope/pre-syncope have co-extant FN, which during 24-month follow-up, does not progress to a persistent deficit (>24 h). Awareness of co-occurrence of FN and syncope is important as stroke misdiagnosis results in aggressive anti-hypertensive management and future events may ensue.

Reduced fractional anisotropy in the uncinate fasciculus in patients with major depression carrying the met-allele of the Val66Met brain-derived neurotrophic factor genotype.

Experimental studies support a neurotrophic hypothesis of major depressive disorder (MDD). The aim of this study was to determine the effect of Val66Met brain-derived neurotrophic factor (BDNF) polymorphism on the white matter fiber tracts connecting hippocampus and amygdala with the prefrontal lobe in a sample of patients with MDD and healthy controls. Thirty-seven patients with MDD and 42 healthy volunteers were recruited. Diffusion tensor imaging (DTI) data with 61 diffusion directions were obtained with MRI 3 Tesla scanner. Deterministic tractography was applied with ExploreDTI and Val66Met BDNF SNP (rs6265) was genotyped. Fiber tracts connecting the hippocampus and amygdala with the prefrontal lobe, namely uncinate fasciculus (UF), fornix, and cingulum were analyzed. A significant interaction was found in the UF between BDNF alleles and diagnosis. Patients carrying the BDNF met-allele had smaller fractional anisotropy (FA) in the UF compared to those patients homozygous for val-allele and compared to healthy subjects carrying the met-allele. A significant three-way interaction was detected between region of the cingulum (dorsal, rostral, and parahippocampal regions), brain hemisphere and BDNF genotype. Larger FA was detectable in the left rostral cingulum for met-allele carriers when compared to val/val alelle carriers. We provide evidence for the importance of the neurotrophic involvement in limbic and prefrontal connections. The met-allele of the BDNF polymorphism seems to render subjects more vulnerable for dysfunctions associated with the UF, a tract known to be related to negative emotional-cognitive processing bias, declarative memory problems, and autonoetic self awareness.

Venous covered stent: successful occlusion of a symptomatic internal iliac arteriovenous fistula.

We report the placement of a covered stent within the internal iliac vein (IIV) to occlude a symptomatic iatrogenic internal iliac arteriovenous fistula following an abdominal aortic graft. Angiography revealed a direct communication between an internal iliac graft to artery anastomosis and the right IIV with rapid shunting into the inferior vena cava and a small associated pseudoaneurysm. Femoral, brachial or axillary arterial access was precluded. The fistula was successfully occluded by a stent-graft placed in the IIV. Arteriovenous fistula can be treated in a number of ways including covered stent placement on the arterial side. To the best of our knowledge this is the first time placement in a vein has been described. Where access is difficult or the procedure carries a high risk of complication, a venous covered stent may offer an alternative.

Neurovascular compression of the trigeminal and glossopharyngeal nerve: three case reports.

Trigeminal neuralgia (TN) is a frequent cause of paroxysmal facial pain and headache in adults. Glossopharyngeal neuralgia (GPN) is less common, but can cause severe episodic pain in the ear and throat. Neurovascular compression of the appropriate cranial nerve as it leaves the brain stem is responsible for the symptoms in many patients, and neurosurgical decompression of the nerve is now a well accepted treatment in adults with both TN and GPN who fail to respond to drug therapy. Neither TN nor GPN are routinely considered in the differential diagnosis when assessing children with paroxysmal facial or head pain, as they are not reported to occur in childhood. Case reports of three children with documented neurovascular compression causing severe neuralgic pain and disability are presented. The fact that these conditions do occur in the paediatric population, albeit rarely, is highlighted, and appropriate investigation and management are discussed.

Pulmonary magnetic resonance angiography.

Early attempts to image the pulmonary vasculature with spin-echo magnetic resonance (MR) imaging were hampered by severe image degradation related to respiratory and cardiac pulsation artifact, susceptibility at interfaces between lung parenchyma and vessel wall, and poor contrast between flowing blood and intravascular filling defects of emboli. With the development of gradient-echo MR angiographic techniques some of these limitations were overcome; however, the need for multiple breath-holds and the frequent occurrence of flow-related artifacts that could simulate pulmonary emboli diminished their clinical utility. With the development of contrast-enhanced MR angiography, many of the limitations of earlier techniques were addressed. Images of both lungs with high signal-to-noise ratios and high contrast between flowing blood and pulmonary emboli could be acquired in a single breath-hold, during "first-pass" imaging with extracellular contrast agents in the coronal plane. However, subsegmental vessels could not be assessed with this approach. The technique has been refined further by imaging each lung separately in the sagittal plane; this offers higher resolution and total lung coverage and requires a shorter breath-hold. Finally, several investigators have reported preliminary data on imaging of the pulmonary vasculature with blood pool agents, exploiting respiratory triggering or navigator echoes to eliminate the need for breath-holding for the detection of pulmonary emboli.

Non-invasive evaluation of the visceral arteries with magnetic resonance angiography.

Traditionally, there have been only a few indications for imaging of the visceral arteries. With improvements in treatment of many mesenteric vascular disorders, it has become more important to establish a diagnosis early in the course of the disease. With the advent of ultrasound, computed tomography and magnetic resonance imaging non-invasive imaging of the visceral arteries became possible, although all these modalities were limited in scope for demonstration of mesenteric pathology. The advent of high-quality mesenteric MR arteriography and venography, which allows comprehensive evaluation of both visceral artery anatomy and function, has led to a huge increase in the number of studies directed at the mesenteric arteries in many departments.

Pulmonary MR angiography.

Imaging of the pulmonary vasculature with "inflow" MR imaging is difficult both to perform and interpret. Over the last few years, however, a greater understanding of contrast-enhanced techniques and the availability of fast gradient performance have facilitated the development of high resolution breath-hold images with high contrast-to-noise ratios. Increasing clinical experience with these contrast-enhanced techniques suggests a likely role for MR angiography in investigating patients with a variety of pulmonary vasculature disorders, including pulmonary embolism, pulmonary hypertension and arterio-venous malformation.

Stepping-table gadolinium-enhanced digital subtraction MR angiography of the aorta and lower extremity arteries: preliminary experience.

PURPOSE: To compare stepping-table digital subtraction gadolinium-enhanced magnetic resonance (MR) angiography of the distal aorta and lower extremity arteries with conventional catheter digital subtraction x-ray angiography in patients with arterio-occlusive disease. MATERIALS AND METHODS: Twenty patients underwent both conventional catheter angiography and fast three-dimensional gadolinium-enhanced MR angiography of the aorta and outflow vessels at 1.5 T; the images were acquired in three consecutive imaging locations during a single infusion of a gadolinium chelate. RESULTS: Compared with catheter angiography, according to the findings of two blinded independent reviewers, MR angiography had sensitivities of 81% and 89% and specificities of 91% and 95%, respectively, for demonstration of insignificant (< or = 50%) stenosis versus significant (51%-100%) stenosis. For demonstration of occlusion, the sensitivity and specificity were 94% and 97%, respectively, by consensus. There was good interobserver correlation between the two readers overall (kappa = 0.65 for reporting the degree of narrowing in all lesions; 0.86, for reporting of insignificant versus significant stenoses; and 0.928, for reporting of occluded versus patient segments). CONCLUSION: Stepping-table digital subtraction contrast material-enhanced MR angiography has high accuracy compared with catheter angiography in patients with arterio-occlusive disease of the aorta and outflow vessels. These preliminary study results suggest that this technique may ultimately provide a safe, noninvasive, and cost-effective alternative to catheter angiography.

Methods of cardiopulmonary support: a review for radiologists.

Physicians are generally aware of the use of bypass pumps during open heart surgery and of the intraaortic balloon pump in treatment of cardiogenic shock. In selected research centers, other advanced methods of cardiopulmonary support are being introduced. Some devices such as the total artificial heart fail clinical trials and disappear from use. Others, like some of the partial artificial hearts, improve outcomes and gain wider clinical use. Some devices temporarily support the circulation in patients recovering from acute circulatory collapse, whereas others provide longer-term circulatory support for patients awaiting transplantation. Permanently implanted devices provide circulatory assistance in cases of chronic, debilitating heart failure. Technology to support lung function in the setting of acute respiratory failure, allowing healing to take place, is also under study. Radiologists should be familiar with the operating principles and radiographic appearances of these emerging techniques to maintain their role as consultants to cardiopulmonary specialists.

Diagnosis of pulmonary embolism with magnetic resonance angiography.

BACKGROUND: Diagnosing pulmonary embolism may be difficult, because there is no reliable noninvasive imaging method. We compared a new noninvasive method, gadolinium-enhanced pulmonary magnetic resonance angiography, with standard pulmonary angiography for diagnosing pulmonary embolism. METHODS: A total of 30 consecutive patients with suspected pulmonary embolism underwent both standard pulmonary angiography and magnetic resonance angiography during the pulmonary arterial phase at the time of an intravenous bolus of gadolinium. All magnetic resonance images were reviewed for the presence or absence of pulmonary emboli by three independent reviewers who were unaware of the findings on standard angiograms. RESULTS: Pulmonary embolism was detected by standard pulmonary angiography in 8 of the 30 patients in whom pulmonary embolism was suspected. All 5 lobar emboli and 16 of 17 segmental emboli identified on standard angiograms were also identified on magnetic resonance images. Two of the three reviewers reported one false positive magnetic resonance angiogram each. As compared with standard pulmonary angiography, the three sets of readings had sensitivities of 100, 87, and 75 percent and specificities of 95, 100, and 95 percent, respectively. The interobserver correlation was good (k=0.57 to 0.83 for all vessels, 0.49 to 1.0 for main and lobar vessels, and 0.40 to 0.81 for segmental vessels). CONCLUSIONS: In this preliminary study, gadolinium-enhanced magnetic resonance angiography of the pulmonary arteries, as compared with conventional pulmonary angiography, had high sensitivity and specificity for the diagnosis of pulmonary embolism. This new technique shows promise as a noninvasive method of diagnosing pulmonary embolism without the need for ionizing radiation or iodinated contrast material.

CT appearance of lipomatous hypertrophy of the interatrial septum.

OBJECTIVE: We undertook this study to determine the CT findings of lipomatous hypertrophy of the interatrial septum, an asymptomatic and underrecognized benign proliferation of fat within the atrial septum. MATERIALS AND METHODS: We retrospectively identified 12 cases of lipomatous hypertrophy of the interatrial septum by searching the radiology records at our institution from 1991 to 1995. We reviewed the CT scans of these patients to determine the distribution and morphology of fat within the interatrial septum. RESULTS: In all patients with lipomatous hypertrophy, a mass of fat attenuation extended from the coronary sinus to just above the level of the aortic root with relative sparing of the fossa ovalis, which resulted in a dumbbell configuration. Average dimensions were 7 cm for craniocaudal extent (range, 6-9 cm), 4.5 cm along the interatrial septum (range, 3.6-6.2 cm), and 2.7 cm perpendicular to the septum (range, 1.5-4.8 cm). Increased epicardial fat was seen on CT scans in 10 patients (83%). CT revealed mediastinal lipomatosis in six patients (50%). No patients had undergone corticosteroid treatment or total parenteral nutrition. No electrocardiographic or functional cardiac abnormalities were seen. CONCLUSION: On standard, high-resolution, and enhanced CT images, lipomatous hypertrophy of the interatrial septum is shown as a nonenhancing smoothly marginated homogeneous dumbbell-shaped mass of fat attenuation confined to the interatrial septum. These characteristic morphologic features allow confident diagnosis and help differentiate this benign condition from other cardiac masses.

Acute respiratory distress syndrome: CT findings during partial liquid ventilation.

To describe the computed tomographic (CT) appearance of perflubron-filled lungs during partial liquid ventilation to treat acute respiratory distress syndrome, scans of the thorax were obtained in nine patients between June 1994 and December 1995. The distribution of perflubron was gravity dependent in four patients, with a mean interval of 6.25 days between scanning and perflubron administration; was patchy in four patients (mean interval, 16 days); and was homogeneous in one patient (interval, 3 days). Extraparenchymal perflubron was seen in intrathoracic lymph nodes (n = 4), supraclavicular nodes (n = 2), axillary nodes (n = 1), and both the retroperitoneum and the mediastinum (n = 2). In one patient, perflubron was seen in a pneumatocele and the pleural space. The distribution of perflubron in the lungs is typically gravity dependent.