Three patients with spinal dural arteriovenous fistula presented with acute and/or progressive my... more Three patients with spinal dural arteriovenous fistula presented with acute and/or progressive myelopathy. The thoracic cord was focally enlarged and poorly defined on MR images in two of the patients. One individual showed focal cord atrophy, and one demonstrated abnormal intrathecal vessels. In all patients MR studies revealed cord enhancement after IV administration of gadopentetate dimeglumine. The MR findings are believed to represent disruption of the blood-cord barrier associated with cord ischemia and/or infarction, which, in turn, is caused by venous stasis resulting from the fistula. The diagnosis in each case was confirmed by the combined results of myelography, spinal arteriography, and surgery. Surgical excision or embolization of the fistula produced a poor return of lost function but an arrest in the progression of paresis. One of the patients had constant severe back and leg pain postoperatively, and a follow-up MR study 5 months after surgery showed focal atrophy an...
One hundred consecutive patients with atlanto-axial dislocation(s) were subjected to posterior oc... more One hundred consecutive patients with atlanto-axial dislocation(s) were subjected to posterior occipito-cervical fusion and followed up to 16 1/2 years postoperatively (mean: 4 1/2 years). The mean age at surgery was 60.3 years. At the time of follow-up, 45 patients had died, mostly due to cardiopulmonary disease. Out of the 100 patients, 67% showed a major improvement and in an additional 14% there was a slight or moderate improvement. Some patients with a stable fusion later developed subaxial dislocation(s) necessitating an anterior fusion which in patients with RA is difficult due to poor bone quality. MRI revealed pannus formation around the odontoid peg in many patients, in several to such a degree that cord compression was evident. Following the posterior fixation, the pannus disappeared or was reduced which may at least partly explain the generally favourable operative outcome following the fixation procedure. Early occipito-cervical fusion appears to prevent further vertica...
A prospective study was undertaken to evaluate the potential of Gd-DTPA-enhanced MR to differenti... more A prospective study was undertaken to evaluate the potential of Gd-DTPA-enhanced MR to differentiate active from inactive demyelinating lesions of the cervical spinal cord. Five patients with elongated high-signal-intensity lesions in the cervical cord on long TR/TE spin-echo MR images and a clinical suspicion of demyelinating disease had MR before and after IV Gd-DTPA. Delayed contrast enhancement (after 45-60 min) of the lesions was seen on short TR/TE images in two patients with clinically active disease, but no enhancement could be detected in three patients with stable disease. The patients with active disease underwent repeated MR examinations until the enhancement disappeared. The decrease in Gd-DTPA enhancement paralleled a decrease in clinical signs and symptoms of cervical myelopathy. MR is useful in evaluating patients suspected of having demyelinating disease. The MR finding of asymptomatic lesions in the brain lends support to the diagnosis of multiple sclerosis. Other ...
PURPOSE To evaluate the middle cerebral artery (MCA) on CT, including its relationship to cerebra... more PURPOSE To evaluate the middle cerebral artery (MCA) on CT, including its relationship to cerebral infarction. METHODS Thirteen patients with either a unilateral or bilateral hyperdense M1 segment of the MCA were evaluated. History of hypertension, diabetes, and hematocrit were obtained and compared with a control group of patients without a hyperdense MCA. RESULTS None of the patients had a unilateral hyperdense MCA ipsilateral to a clinically identifiable stroke. Patients with a hyperdense MCA had a statistically higher hematocrit and also a higher prevalence of hypertension and diabetes mellitus than patients without a hyperdense MCA. The higher hematocrit may have increased the density of the blood, while both diabetes and hypertension are associated with calcification within blood vessel walls. CONCLUSION A hyperdense MCA is not a reliable indicator of occlusion of this vessel or subsequent infarction.
To evaluate if magnetic resonance imaging (MRI) is superior to conventional radiography for detec... more To evaluate if magnetic resonance imaging (MRI) is superior to conventional radiography for detection of erosions in the fifth metatarsophalangeal (MTP5) joint. Within one year from the onset of rheumatoid arthritis (RA) (baseline), one and three years thereafter MRI and conventional radiographs of the MTP5 joint were performed in 23 patients. MRI revealed erosions in 10 patients at baseline, in 15 after one year and in 15 patients after 3 years. On conventional radiography, there were erosions in 10 patients at baseline, 16 after one year as well as after 3 years. The agreement between the two imaging methods was fair to good at baseline and after one and three years (kappa 0,65, 0,51 and 0,51 respectively). The number of patients with clinical evidence of synovitis decreased considerably over time although the number of patients with MRI-synovitis was unchanged and the number of patients with erosions increased. MRI was not superior to conventional radiography in detecting erosions in MTP5 joints in patients with early RA. Most erosions developed during the first year of observation. Synovitis on MRI may be a marker of future development of erosions in the MTP5 joint.
In order to optimize the coil selection for cervical and thoracic spine imaging the signal charac... more In order to optimize the coil selection for cervical and thoracic spine imaging the signal characteristics of two different solenoidal surface coils (15 cm and 30 cm diameter, respectively) as well as the head coil and body coil were determined using a 0.3 T MR scanner with a vertical magnetic field. Signal-to-noise ratio curves were obtained for each coil using tube phantoms and a human-like phantom. The findings were compared with images obtained in two healthy volunteers. The head coil was found to be superior for imaging of the cranio-cervical junction while the 15 cm surface coil gave better results in the remaining part of the cervical spine and the upper thoracic spine. The body coil was superior for imaging of the thoracic region at the level of the shoulders (T4-T6) but the 30 cm surface coil was better for the more caudal part of the thoracic spine. Combined phantom and in vivo studies are also recommended for evaluation of future, improved coils.
Twenty-six patients with cervical radiculopathy and/or myelopathy caused by spondylosis or disk h... more Twenty-six patients with cervical radiculopathy and/or myelopathy caused by spondylosis or disk herniation were examined with myelography, CT myelography and MR. Fourteen of the patients were operated upon and 11 of them underwent postoperative MR and CT. The three radiologic methods provided comparable information about narrowing of the subarachnoid space and compression of the spinal cord. It was more difficult to distinguish bone from soft tissue with MR only, but the combination of MR and conventional radiography gave sufficient information for this differentiation. When radiologic nerve root sheath deformity was compared with clinical radiculopathy, myelography, CT myelography and MR had similar sensitivity and accuracy. Postoperative MR could reveal remaining indentation on the thecal sac and the cord but CT without contrast medium was useful as a complement to determine the aetiology of the indentation. Because MR has several practical advantages, it is well suited as the primary imaging modality, together with conventional radiography, for the preoperative radiologic evaluation of patients with cervical radiculopathy and/or myelopathy. Postoperative MR is useful in patients with persistent or new symptoms.
International journal of obesity (2005), Jan 26, 2017
We investigated five methylation markers recently linked to body mass index, for their role in th... more We investigated five methylation markers recently linked to body mass index, for their role in the neuropathology of obesity. In neuroimaging experiments, our analysis involving 23 participants showed that methylation levels for the cg07814318 site, which lies within the KLF13 gene, correlated with brain activity in the claustrum, putamen, cingulate gyrus and frontal gyri, some of which have been previously associated to food signaling, obesity or reward. Methylation levels at cg07814318 also positively correlated with ghrelin levels. Moreover, expression of KLF13 was augmented in the brains of obese and starved mice. Our results suggest the cg07814318 site could be involved in orexigenic processes, and also implicate KLF13 in obesity. Our findings are the first to associate methylation levels in blood with brain activity in obesity-related regions, and further support previous findings between ghrelin, brain activity and genetic differences.International Journal of Obesity advance ...
International angiology : a journal of the International Union of Angiology, 2003
Endovascular repair of abdominal aortic aneurysms (AAA) necessitates a long-term follow-up. These... more Endovascular repair of abdominal aortic aneurysms (AAA) necessitates a long-term follow-up. These patients are often old and renal insufficiency is not unusual. Cost-effectiveness needs to be addressed in evaluating methods of follow-up. The aim of this study was to compare costs of 5 years follow-up with magnetic resonance imaging with contrast enhanced three-dimensional magnetic resonance angiography (MRI/MRA) with follow-up using CT with DSA, or CTA. We also assessed the impact of contrast media induced (CMI) nephropathy on follow-up costs. We have implemented Swedish costs of CT with DSA, and CTA on the reported follow-up examinations from the EUROSTAR progress report 2000. The costs of follow-up with CT with DSA, or CTA were compared to a follow-up protocol with MRI/MRA. A cost analysis including a risk analysis of CMI nephropathy was made between MRI/MRA and CT with DSA, or CTA. Excluding the risk of CMI nephropathy, the 5 years follow-up cost in Euro ( ) with MRI/MRA ( 5715) ...
Twenty-eight patients with abdominal aortic aneurysm were examined by computed tomography (CT) an... more Twenty-eight patients with abdominal aortic aneurysm were examined by computed tomography (CT) and aortography. They subsequently underwent aneurysmectomy and reconstruction of the aorta. CT provided in most of the cases the same or more accurate preoperative information than aortography. CT is comfortable for the patient, less invasive and faster than aortography and can be done as an outpatient procedure. Thus, we recommend CT to be the primary method for preoperative evaluation of abdominal aortic aneurysm. In selected cases aortography gives additional information regarding the relationship to the renal arteries (when the aorta is very tortuous), the occurrence of renal artery stenosis, and peripheral vascular disease.
Three patients with spinal dural arteriovenous fistula presented with acute and/or progressive my... more Three patients with spinal dural arteriovenous fistula presented with acute and/or progressive myelopathy. The thoracic cord was focally enlarged and poorly defined on MR images in two of the patients. One individual showed focal cord atrophy, and one demonstrated abnormal intrathecal vessels. In all patients MR studies revealed cord enhancement after IV administration of gadopentetate dimeglumine. The MR findings are believed to represent disruption of the blood-cord barrier associated with cord ischemia and/or infarction, which, in turn, is caused by venous stasis resulting from the fistula. The diagnosis in each case was confirmed by the combined results of myelography, spinal arteriography, and surgery. Surgical excision or embolization of the fistula produced a poor return of lost function but an arrest in the progression of paresis. One of the patients had constant severe back and leg pain postoperatively, and a follow-up MR study 5 months after surgery showed focal atrophy an...
One hundred consecutive patients with atlanto-axial dislocation(s) were subjected to posterior oc... more One hundred consecutive patients with atlanto-axial dislocation(s) were subjected to posterior occipito-cervical fusion and followed up to 16 1/2 years postoperatively (mean: 4 1/2 years). The mean age at surgery was 60.3 years. At the time of follow-up, 45 patients had died, mostly due to cardiopulmonary disease. Out of the 100 patients, 67% showed a major improvement and in an additional 14% there was a slight or moderate improvement. Some patients with a stable fusion later developed subaxial dislocation(s) necessitating an anterior fusion which in patients with RA is difficult due to poor bone quality. MRI revealed pannus formation around the odontoid peg in many patients, in several to such a degree that cord compression was evident. Following the posterior fixation, the pannus disappeared or was reduced which may at least partly explain the generally favourable operative outcome following the fixation procedure. Early occipito-cervical fusion appears to prevent further vertica...
A prospective study was undertaken to evaluate the potential of Gd-DTPA-enhanced MR to differenti... more A prospective study was undertaken to evaluate the potential of Gd-DTPA-enhanced MR to differentiate active from inactive demyelinating lesions of the cervical spinal cord. Five patients with elongated high-signal-intensity lesions in the cervical cord on long TR/TE spin-echo MR images and a clinical suspicion of demyelinating disease had MR before and after IV Gd-DTPA. Delayed contrast enhancement (after 45-60 min) of the lesions was seen on short TR/TE images in two patients with clinically active disease, but no enhancement could be detected in three patients with stable disease. The patients with active disease underwent repeated MR examinations until the enhancement disappeared. The decrease in Gd-DTPA enhancement paralleled a decrease in clinical signs and symptoms of cervical myelopathy. MR is useful in evaluating patients suspected of having demyelinating disease. The MR finding of asymptomatic lesions in the brain lends support to the diagnosis of multiple sclerosis. Other ...
PURPOSE To evaluate the middle cerebral artery (MCA) on CT, including its relationship to cerebra... more PURPOSE To evaluate the middle cerebral artery (MCA) on CT, including its relationship to cerebral infarction. METHODS Thirteen patients with either a unilateral or bilateral hyperdense M1 segment of the MCA were evaluated. History of hypertension, diabetes, and hematocrit were obtained and compared with a control group of patients without a hyperdense MCA. RESULTS None of the patients had a unilateral hyperdense MCA ipsilateral to a clinically identifiable stroke. Patients with a hyperdense MCA had a statistically higher hematocrit and also a higher prevalence of hypertension and diabetes mellitus than patients without a hyperdense MCA. The higher hematocrit may have increased the density of the blood, while both diabetes and hypertension are associated with calcification within blood vessel walls. CONCLUSION A hyperdense MCA is not a reliable indicator of occlusion of this vessel or subsequent infarction.
To evaluate if magnetic resonance imaging (MRI) is superior to conventional radiography for detec... more To evaluate if magnetic resonance imaging (MRI) is superior to conventional radiography for detection of erosions in the fifth metatarsophalangeal (MTP5) joint. Within one year from the onset of rheumatoid arthritis (RA) (baseline), one and three years thereafter MRI and conventional radiographs of the MTP5 joint were performed in 23 patients. MRI revealed erosions in 10 patients at baseline, in 15 after one year and in 15 patients after 3 years. On conventional radiography, there were erosions in 10 patients at baseline, 16 after one year as well as after 3 years. The agreement between the two imaging methods was fair to good at baseline and after one and three years (kappa 0,65, 0,51 and 0,51 respectively). The number of patients with clinical evidence of synovitis decreased considerably over time although the number of patients with MRI-synovitis was unchanged and the number of patients with erosions increased. MRI was not superior to conventional radiography in detecting erosions in MTP5 joints in patients with early RA. Most erosions developed during the first year of observation. Synovitis on MRI may be a marker of future development of erosions in the MTP5 joint.
In order to optimize the coil selection for cervical and thoracic spine imaging the signal charac... more In order to optimize the coil selection for cervical and thoracic spine imaging the signal characteristics of two different solenoidal surface coils (15 cm and 30 cm diameter, respectively) as well as the head coil and body coil were determined using a 0.3 T MR scanner with a vertical magnetic field. Signal-to-noise ratio curves were obtained for each coil using tube phantoms and a human-like phantom. The findings were compared with images obtained in two healthy volunteers. The head coil was found to be superior for imaging of the cranio-cervical junction while the 15 cm surface coil gave better results in the remaining part of the cervical spine and the upper thoracic spine. The body coil was superior for imaging of the thoracic region at the level of the shoulders (T4-T6) but the 30 cm surface coil was better for the more caudal part of the thoracic spine. Combined phantom and in vivo studies are also recommended for evaluation of future, improved coils.
Twenty-six patients with cervical radiculopathy and/or myelopathy caused by spondylosis or disk h... more Twenty-six patients with cervical radiculopathy and/or myelopathy caused by spondylosis or disk herniation were examined with myelography, CT myelography and MR. Fourteen of the patients were operated upon and 11 of them underwent postoperative MR and CT. The three radiologic methods provided comparable information about narrowing of the subarachnoid space and compression of the spinal cord. It was more difficult to distinguish bone from soft tissue with MR only, but the combination of MR and conventional radiography gave sufficient information for this differentiation. When radiologic nerve root sheath deformity was compared with clinical radiculopathy, myelography, CT myelography and MR had similar sensitivity and accuracy. Postoperative MR could reveal remaining indentation on the thecal sac and the cord but CT without contrast medium was useful as a complement to determine the aetiology of the indentation. Because MR has several practical advantages, it is well suited as the primary imaging modality, together with conventional radiography, for the preoperative radiologic evaluation of patients with cervical radiculopathy and/or myelopathy. Postoperative MR is useful in patients with persistent or new symptoms.
International journal of obesity (2005), Jan 26, 2017
We investigated five methylation markers recently linked to body mass index, for their role in th... more We investigated five methylation markers recently linked to body mass index, for their role in the neuropathology of obesity. In neuroimaging experiments, our analysis involving 23 participants showed that methylation levels for the cg07814318 site, which lies within the KLF13 gene, correlated with brain activity in the claustrum, putamen, cingulate gyrus and frontal gyri, some of which have been previously associated to food signaling, obesity or reward. Methylation levels at cg07814318 also positively correlated with ghrelin levels. Moreover, expression of KLF13 was augmented in the brains of obese and starved mice. Our results suggest the cg07814318 site could be involved in orexigenic processes, and also implicate KLF13 in obesity. Our findings are the first to associate methylation levels in blood with brain activity in obesity-related regions, and further support previous findings between ghrelin, brain activity and genetic differences.International Journal of Obesity advance ...
International angiology : a journal of the International Union of Angiology, 2003
Endovascular repair of abdominal aortic aneurysms (AAA) necessitates a long-term follow-up. These... more Endovascular repair of abdominal aortic aneurysms (AAA) necessitates a long-term follow-up. These patients are often old and renal insufficiency is not unusual. Cost-effectiveness needs to be addressed in evaluating methods of follow-up. The aim of this study was to compare costs of 5 years follow-up with magnetic resonance imaging with contrast enhanced three-dimensional magnetic resonance angiography (MRI/MRA) with follow-up using CT with DSA, or CTA. We also assessed the impact of contrast media induced (CMI) nephropathy on follow-up costs. We have implemented Swedish costs of CT with DSA, and CTA on the reported follow-up examinations from the EUROSTAR progress report 2000. The costs of follow-up with CT with DSA, or CTA were compared to a follow-up protocol with MRI/MRA. A cost analysis including a risk analysis of CMI nephropathy was made between MRI/MRA and CT with DSA, or CTA. Excluding the risk of CMI nephropathy, the 5 years follow-up cost in Euro ( ) with MRI/MRA ( 5715) ...
Twenty-eight patients with abdominal aortic aneurysm were examined by computed tomography (CT) an... more Twenty-eight patients with abdominal aortic aneurysm were examined by computed tomography (CT) and aortography. They subsequently underwent aneurysmectomy and reconstruction of the aorta. CT provided in most of the cases the same or more accurate preoperative information than aortography. CT is comfortable for the patient, less invasive and faster than aortography and can be done as an outpatient procedure. Thus, we recommend CT to be the primary method for preoperative evaluation of abdominal aortic aneurysm. In selected cases aortography gives additional information regarding the relationship to the renal arteries (when the aorta is very tortuous), the occurrence of renal artery stenosis, and peripheral vascular disease.
In this chapter, the advantages and disadvantages of 3D fast spin echo (FSE) pCASL as a measure o... more In this chapter, the advantages and disadvantages of 3D fast spin echo (FSE) pCASL as a measure of brain tumor perfusion are reviewed. In addition, we compare pCASL with other perfusion techniques and discuss future ASL approaches. A prospective study of 28 patients with contrast-enhancing brain tumors was performed at 3 T using dynamic susceptibility contrast (DSC) MRI and pCASL. The visual qualitative evaluation of signal enhancement in tumor was scored from 0 to 3 (0 = no signal enhancement compared with white matter (WM), 3 = pronounced signal enhancement with similar or higher signal intensity than in gray matter (GM)/basal ganglia). The extent of susceptibility artifacts in the tumor was scored from 0 to 2 (0 = no susceptibility artifacts, 2 = extensive susceptibility artifacts (maximum diameter >2 cm). Absolute ASL cerebral blood flow (CBF) values in tumor, GM, WM, and cerebellum were also measured. Using normalized tumor blood flow values (ASL nTBF, DSC nTBF), tumor-to-healthy tissue perfusion ratios were calculated by dividing the mean value of tumor ROI by the mean value in ROIs in the two cerebellar hemispheres. ASL had in comparison with DSC-MRI both a lower signal enhancement score (p = 0.02) and a lower susceptibility artifact score (p < 0.01). The highest absolute ASL CBF values were measured in tumor tissue and the lowest in WM. There was a good correlation between DSC nTBF and ASL nTBF values, with a correlation coefficient of 0.82.
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