Defining the anterior nucleus of the thalamus (ANT) as a deep brain stimulation target in refractory epilepsy: Delineation using 3 T MRI and intraoperative microelectrode recording.

BACKGROUND: Deep brain stimulation (DBS) is a minimally invasive and reversible method to treat an increasing number of neurological and psychiatric disorders, including epilepsy. Targeting poorly defined deep structures is based in large degree on stereotactic atlas information, which may be a major source of inconsistent treatment effects. AIM OF THE STUDY: In the present study, we aimed to study whether a recently approved target for epilepsy (anterior nucleus of thalamus, ANT) is visualized in clinically established 3 T MRI and whether ANT is delineated using intraoperative microelectrode recording (MER). We have especially focused on individual variation in the location of ANT in stereotactic space. We also aimed to demonstrate the role of individual variation in interpretation of MER data by projecting samples onto AC-PC (anterior and posterior commissure) and ANT-normalized coordinate systems. METHODS: Detailed analysis of ANT delineations in 3 T MRI short tau inversion recovery (STIR) images from eight patients undergoing DBS for refractory epilepsy was performed. Coronal and sagittal cross-sectional models of ANT were plotted in the AC-PC coordinate system to study individual variation. A total of 186 MER samples collected from 10 DBS trajectories and 5 patients were analyzed, and the location of each sample was calculated and corrected accordingly to the location of the final DBS electrode and projected to the AC-PC or coordinate system normalized to ANT. RESULTS: Most of the key structures in the anatomic atlas around ANT (mammillothalamic tract and external medullary lamina) were identified in STIR images allowing visual delineation of ANT. We observed a high degree of anatomical variation in the location of ANT, and the cross-sectional areas overlapped by study patients decreased in a linear fashion with an increasing number of patients. MER information from 10 individual trajectories correlated with STIR signal characteristics by demonstrating a spike-negative zone, presumably white matter layer, at the lateral aspect of ANT in ANT-normalized coordinate system as predicted by STIR images. However, MER information projected to the AC-PC coordinate system was not able to delineate ANT. CONCLUSIONS: ANT is delineated in 3 T MRI by visualization of a thin white matter lamina between ANT and other nuclear groups that lack spiking activity. Direct targeting in the anterior thalamic area is superior to indirect targeting due to extensive individual variation in the location of ANT. Without detailed imaging information, however, a single trajectory MER has little localizing value.

Magnetic resonance imaging of acute scrotum.

BACKGROUND AND AIMS: The aim of the pilot study was to evaluate the feasibility of dynamic contrast enhanced (CE)-magnetic resonance imaging (MRI) in the detection of testicular ischemia and its ability to differentiate testicle torsion from other causes of acute scrotum. MATERIAL AND METHODS: Seventeen boys or young men with an acute scrotum were included in the prospective study during the time period from October 2001 to December 2005. The median age of the patients was 16,4 (7-44) years. The duration of the symptoms preceding the MRI study varied from six hours to 30 days. The study protocol included physical examination by a surgeon, laboratory tests and Doppler ultrasound (DUS) and finally testicles were imaged by using a 1,5 T MRI scanner; T1-weighted and diffusion weighted images were produced. The gadolinium uptake, reported as the region of interest (ROI) perfusion values and presented as curves, was compared between the affected and contralateral testicle. In testicles with normal blood circulation the ROI values increased during the imaging time. Nine patients were operated on, because the spermatic cord torsion could not be excluded by clinical or DUS findings. RESULTS AND CONCLUSIONS: All the normal testicles gave increasing ROI values meanwhile all three testicles with torsion gave constantly low values referring to no perfusion. Other causes of acute scrotum, such as epididymitis and torsion of testicular appendage seemed to be related with normal perfusion. Dynamic CE-MRI seems to show reliably ischemia of testicle and thus it may be helpful in selecting patients with acute scrotum for urgent operation.

Long-term follow-up study of endovascularly treated intracranial aneurysms.

Long-term follow-up studies after endovascular treatment for intracranial aneurysm are still rare and inconclusive. The aim of this study was to assess long-term clinical and angiographic outcome of patients with endovascularly treated aneurysms. The Clinical outcome of all 185 patients with endovascularly treated aneurysms were analyzed and 77 out of 122 surviving patients were examined with MRI and MRA nine to 16 years (mean 11 years) after the initial endovascular treatment. Sixty-three patients were deceased at the time of follow-up. The cause of death was aneurysm-related in 34 (54%) patients. The annual rebleeding rate from the treated aneurysms was 1.3% in the ruptured group and 0.1% in the unruptured group. In long-term follow-up MRA 18 aneurysms (53%) were graded as complete, 11 aneurysms (32%) had neck remnants and five aneurysms (15%) were incompletely occluded in the ruptured group. Occlusion grade was lower in the unruptured group with 20 aneurysms (41%) graded as complete, 11 (22%) had neck remnants and 18 (37%) were incomplete. However, only three aneurysms were unstable during the follow-up period and needed retreatment. Endovascular treatment of unruptured aneurysms showed incomplete angiographic outcome in 37% of cases. However, annual bleeding rate was as low as 0.1%. Endovascular treatment of ruptured aneurysms showed incomplete angiographic outcome in 15% of cases and the annual rebleeding rate was 1.3%.

Long-term follow-up study of endovascularly treated intracranial aneurysms.

Long-term follow-up studies after endovascular treatment for intracranial aneurysm are still rare and inconclusive. The aim of this study was to assess the long-term clinical and angiographic outcome of patients with endovascularly treated aneurysms. The clinical outcome of all 185 patients with endovascularly treated aneurysms were analyzed and 77 out of 122 surviving patients were examined with MRI and MRA nine to 16 years (mean 11 years) after the initial endovascular treatment. Sixty-three patients were deceased at the time of follow-up. The cause of death was aneurysm-related in 34 (54%) patients. The annual rebleeding rate from the treated aneurysms was 1.3% in the ruptured group and 0.1% in the unruptured group. In long-term follow-up MRA 18 aneurysms (53%) were graded as complete, 11 aneurysms (32%) had neck remnants and five aneurysms (15%) were incompletely occluded in the ruptured group. The occlusion grade was lower in the unruptured group with 20 aneurysms (41%) graded as complete, 11 (22%) had neck remnants and 18 (37%) were incomplete. However, only three aneurysms were unstable during the follow-up period and needed retreatment. Endovascular treatment of unruptured aneurysms showed incomplete angiographic outcome in 37% of cases. However, the annual bleeding rate was as low as 0.1%. Endovascular treatment of ruptured aneurysms showed incomplete angiographic outcome in 15% of cases and the annual rebleeding rate was 1,3%.

Incidence of regurgitation and pulmonary aspiration of gastric contents in survivors from out-of-hospital cardiac arrest.

BACKGROUND: The regurgitation of gastric contents and subsequent pulmonary aspiration remain serious adverse events in cardiac arrest and cardiopulmonary resuscitation. The aim of this study was to determine the association between clinical signs of regurgitation and radiological findings consistent with aspiration in resuscitated out-of-hospital cardiac arrest (OHCA) patients admitted to hospital. METHODS: The incidence of regurgitation was studied in 182 successfully resuscitated OHCA patients. The inclusion criterion was the restoration of spontaneous circulation after OHCA not caused by trauma or drug overdose. RESULTS: The incidence of regurgitation was 20%. Regurgitation was associated with radiological findings consistent with aspiration with a high specificity (81%) and a low sensitivity (46%). CONCLUSIONS: Although there was a strong association between clinical regurgitation and radiological findings consistent with aspiration, our data suggest that regurgitation is not invariably followed by radiological findings compatible with aspiration. Radiological findings consistent with aspiration are relatively infrequent without preceding signs of regurgitation in resuscitated patients.

Postprocedural monitoring of cerebral aneurysms.

The treatment of intracranial aneurysms has been revolutionized since the introduction of electrolytically detachable platinum coils in 1991. Since this basic innovation, many refinements of the embolic materials and techniques have emerged. Today, in Europe, half of all aneurysms are treated endoarterially and this share is growing. The reassuring results of the International Subarachnoid Aneurysm Trial (ISAT) have changed the treatment strategy from neurosurgical clipping to embolization. However, the role of these alternative modes of treatment varies between institutions and countries. An angiographic follow-up pattern after endovascular treatment has remained largely undefined and in the same way there has been much diversity in applying alternative imaging modalities. Although some institutions continue to perform intervalled digital subtraction angiography, magnetic resonance angiography has assumed an increasing role. A vast majority of patients with embolized aneurysms are eligible to be monitored solely by non-contrast three-dimensional time-of-flight technique.

Magnetic resonance imaging of experimental testicular torsion.

We investigated the feasibility of contrast enhanced (CE)-dynamic magnetic resonance imaging (MRI) for the detection of testicular torsion induced hypoperfusion in an experimental rat model. Adult Sprague-Dawley rats were subjected to unilateral testicular torsion of 360 or 720 degrees. After 1 h, the tail veins of the anaesthetized rats were cannulated and T2 -, diffusion-weighted and T1-weighted CE-dynamic MRI were subsequently performed by a 1.5 T MRI scanner. On apparent diffusion coefficient (ADC) images, the region of interest values of the ischaemic and control testes was compared. From CE-dynamic MR images, the maximal slopes of contrast enhancement were calculated and compared. In testicular torsion of 360 degrees, the maximal slope of contrast enhancement was 0.072%/s vs. 0.47%/s in the contralateral control testis (p < 0.001). A torsion of 720 degrees diminished the slope of contrast enhancement to 0.046%/s vs. 0.37%/s in the contralateral testis (p < 0.001). Diminished blood flow during torsion also followed in decreased ADC values in both 360 degrees (12.4% decrease; p < 0.05) and 720 degrees (10.8% decrease; p < 0.001) of torsion. Torsion of the testis causes ipsilateral hypoperfusion and decreased gadolinium uptake in a rat model that can be easily detected and quantified by CE-dynamic MRI. In diffusion-weighted MRI images, acute hypoperfusion results in a slight decrease of ADC values. Our results suggest that CE-dynamic MRI in combination with diffusion-weighted MRI can be used to detect compromised blood flow due to acute testicular torsion.

Long-term results and quality of life after endovascular treatment of venous malformations in the face and neck.

PURPOSE: To evaluate the long-term results of endovascular sclerotherapy in treating venous and venocapillary malformations of the face and neck region, and to assess the quality of life after treatment. MATERIAL AND METHODS: Twenty consecutive patients with endovascularly treated venous and capillary-venous malformation of the face and neck were invited to attend for clinical control and magnetic resonance (MR) imaging. To evaluate the quality of life after treatment, patients were asked to fill in a questionnaire which included 20 multiple-choice questions exploring 4 dimensions: psychological, physical, and social functioning, and pain. RESULTS: In 14 patients, symptoms and MR findings improved, while in 6 patients there was no improvement. Results concerning quality of life showed that most patients did well after endovascular treatment. Patients with venous malformations of the tongue had a worse outcome. Patients under the age of 16 at the beginning of the treatment and patients clinically followed by physicians specialized in vascular malformations had a better quality of life. CONCLUSION: Endovascular treatment for venous malformations is effective. Results and quality of life proved to be better when the endovascular treatment was begun before puberty and the patients had regular clinical controls after therapy.

Vertebral epidural arteriovenous fistula and radicular pain in neurofibromatosis type I.

A minor trauma caused opening of an arteriovenous fistula between the right vertebral artery and cervical spinal epidural venous plexus in a patient with neurofibromatosis Type I. Subsequent dilation of the plexus caused compression of the spinal cord and radicular symptomology of the right upper extremity. The single-hole fistula and its arterial feeder were filled with electrodetachable coils via an intra-arterial approach. This lead into shrinkage of the plexus, reformation of the cord caliber and full and stable clinical recovery. The achieved endovascular occlusion of the fistula proved to be permanent on follow-up.

Delayed MR imaging changes in acute disseminated encephalomyelitis.

BACKGROUND AND PURPOSE: White matter lesions on MR images obtained from patients with acute disseminated encephalomyelitis (ADEM) have been reported to appear shortly after symptom onset, and their resolution has been claimed to parallel recovery. To elucidate the temporal evolution of these lesions and to associate the changes on MR images to the patients' clinical condition, we performed serial MR imaging on patients with ADEM. METHODS: Several consecutive T2-weighted and fluid-attenuated inversion recovery scans were obtained from four previously healthy adult patients with ADEM within the first days after the onset of symptoms and again during the recovery period. MR imaging was done first on a weekly to biweekly basis and later at 1- to 2-month intervals for up to 8 months. RESULTS: MR scans of three of these patients did not show any specific abnormalities until several weeks after the onset of the disease. As the lesions later appeared, their number increased during the recovery period. CONCLUSION: MR imaging performed during the first days after the onset of the disease may not reveal any pathologic findings. The appearance of the ADEM-associated MR imaging changes may be associated with recovery rather than decline. It remains to be studied whether the new MR imaging techniques reveal the lesions associated with ADEM faster than the conventional T2-weighted imaging.

Reversible posterior leukoencephalopathy after combination chemotherapy.

We describe a young woman with Burkitt's lymphoma, treated with intravenous adriamycine and cyclophosphamide and intrathecal cytarabine. She developed a reversible posterior leukoencephalopathy syndrome (RPLS) with typical MRI findings. Diffusion-weighted images during the first days after the onset of symptoms predicted a small irreversible lesion in the frontal lobe, verified on T2-weighted images 1 month later. The patient showed full recovery after high-dose steroid treatment.

MR angiography with three-dimensional time-of-flight and targeted maximum-intensity-projection reconstructions in the follow-up of intracranial aneurysms embolized with Guglielmi detachable coils.

BACKGROUND AND PURPOSE: Intra-arterial contrast angiographies are generally used to confirm treatment results of endovascular neurointerventions such as aneurysm obliteration. We compared MR angiography with digital subtraction angiography (DSA) as a follow-up technique for the detection of aneurysmal remnant cavities and arterial patency in patients treated for intracranial aneurysms with Guglielmi detachable coils (GDCs). METHODS: In 20 consecutive patients, follow-up MR angiography and routine intra-arterial cerebral angiography were performed on the same day 1 to 7 months (mean, 4.5 months) after embolization with GDCs. MR angiographic data were postprocessed for subvolume maximum intensity projections centered on the region of the treated aneurysm. Hard copies of both imaging studies were interpreted independently in a blinded fashion to record and compare remnant cavities, location of residual flow, and adjacent arterial narrowing, using DSA as the standard of reference. The interpreters also established an occlusion grade for the treated aneurysms as evidenced on DSA images and evaluated MR angiograms for artifactual effects. RESULTS: Overall sensitivity and positive predictive value of MR angiography in revealing aneurysmal remnant cavities were both 90%. Specificity in ruling out a remnant cavity with MR angiography was 91%. One remnant cavity was missed by MR angiography, and in five patients, false adjacent arterial encroachments were reported. CONCLUSION: MR angiography may be useful in the long-term follow-up of successfully treated small and medium-sized aneurysms after concurrent primary verification of their occlusion with DSA.

Patient outcome after endovascular treatment of intracranial aneurysms with reference to microsurgical clipping.

OBJECTIVES: Endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDC) has found growing acceptance worldwide, and partially replaced conventional microsurgery. In this study clinical and angiographical results of embolization are reviewed. In addition, long-term neuropsychological patient outcome with reference to surgery is assessed. Indications for screening and follow-up of the patients as limitations and recent achievements of aneurysm embolization are discussed. MATERIAL AND METHODS: Angiographical and clinical follow-up of the first 44 patients with 48 GDC-coiled aneurysms are reviewed. Postprocedural clinical, emotional and social (CES) outcome on disability scale as scored from postal questionnaire data is presented and compared to 106 currently operated patients. RESULTS: In 75% of the embolized aneurysms successful occlusion was achieved, procedural mortality was 2.3% and morbidity 18.2%. Clinical status of all 15 patients with unruptured aneurysms preserved. Of the surviving 29 patients with ruptured aneurysms 12 improved and the rest preserved their clinical status. In 91% of the embolized patients and in 85% of the operated patients CES outcome was categorized as good or excellent. The difference was statistically nonsignificant. CONCLUSION: Embolization with GDC is a feasible, effective and safe mini-invasive method in small aneurysms with a small neck. However, intentional parent artery occlusion, novel endovascular techniques and embolic agents or supplementary surgery may be necessary in selected cases. Neuropsychological long-term outcome of the patients treated for an intracranial aneurysm does not differ much between GDC embolization and microsurgical clipping.

Diagnosis and embolizing of spinal arteriovenous malformations.

Spinal arteriovenous malformations are uncommon disorders associated with considerable difficulty in diagnosis and treatment. They are divided into dural arteriovenous fistulas and intradural medullary spinal cord angiomas. In this retrospective series of six patients the clinical outcome of embolization is presented. The patient material consisted of three dural fistulas and three cord angiomas, one of which bled causing sudden paresis, pain and incontinence. In the remaining five patients the symptoms were progressive consisting of paraesthaesias, paraparesis, pain and incontinence. The clinical status of four patients was not changed after the treatment, one deterioriated and one improved. There were no bleedings after the therapy. In one patient spinal angiography for follow-up was performed and recanalization was seen in the dural fistula after particle embolization. Also, in one cord angioma embolized with particles reflow appeared in the immediately repeated angiography. For permanent angioma occlusion tissue adhesive is preferred as embolic material. Surgical therapy as an alternative or adjuvant to embolization is discussed with a review of the literature. Early timing of the therapeutic intervention is stressed to avoid the development of irreversible ischaemic medullopathy and to prevent haemorrhage. The therapeutic procedures at the early stage of the disease may be curable or, at least, halt the progression of the symptoms. Cross-sectional imaging studies and myelographies may reveal the lesion. For the definitive diagnosis of spinal angioma with its vascular feeders and for the evaluation of its occlusion grade after the therapy selective spinal angiography is needed.

Diagnostic performance of a teleradiology system in primary health care.

Open health care needs proper basic radiological services. Teleradiology makes it possible to get the radiologist's consultation in rural and remote areas and allows the transmission of images between hospitals. A microcomputer-based teleradiology system using a 512 x 512 x 8 bit image matrix with image-processing capabilities and obtainable at a cost of US$ 20,000 was evaluated in daily practice. Images from 372 conventional roentgen examinations were digitized and transmitted via a 64 Kbits/s telephone line from a rural health center to a university hospital, where they were interpreted by two radiologists. The original radiographs were interpreted later and the two reports compared to evaluate the diagnostic performance of system. Slight deterioration of image quality was noticed, though the images were non-diagnostic only in a few cases. The image-processing capability of the system was assessed as useful. Major discrepancies between CRT and film readings were noted in 3.9% of the cases interpreted. The accuracy of CRT readings was about 2% poorer in chest examinations and 5% poorer in bone examinations than in film readings. The teleradiology system proved sufficient for consultation in most conventional radiographs in daily practice, although a system based on a 1024 x 1024 matrix is desirable.

Comparison of incentive spirometry and intermittent positive pressure breathing after coronary artery bypass graft.

Fifty-two patients were randomized to receive either incentive spirometry (IS) or intermittent positive pressure breathing (IPPB) in addition to conventional chest physical therapy following coronary artery bypass grafting. Slow vital capacity and peak expiratory flow readings decreased rapidly and to an equal extent in both groups after surgery, and partly recovered by the sixth postoperative day (POP). Arterial PO2 values were similar for the groups on the first three POPs. On the POPs 2, 3, and 6, the number of chest films showing atelectases as well as the number of individual patients having atelectases revealed no statistically significant differences between the two groups. Based on the three variables studied, we consider both devices equal in efficiency after coronary surgery.