| 1. |
- Annertz, Mårten, et al.
(författare)
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Serial MRI in the early postoperative period after lumbar discectomy
- 1995
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Ingår i: Neuroradiology. - 1432-1920. ; 37:3, s. 177-182
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine MRI findings in patients successfully operated upon for lumbar disc herniation. We investigated 20 patients with a successful outcome after L4-5 or L5-S1 disc operations clinically and with MRI preoperatively, and at 5 days, 6 weeks, and 4 months after surgery. Postoperatively, T1- and T2-weighted images were obtained. At 4 months gadolinium-enhanced images were added. Pronounced intraspinal MRI changes were seen during follow-up. Deformation of the dural sac was seen in 13 patients preoperatively, in 19 at 5 days after operation, in 15 at 6 weeks, and in 12 at 4 months. Nerve root involvement was seen in all cases both preoperatively and at 5 days after operation, in 17 at 6 weeks, and in 15 at 4 months. No correlation between symptoms or the straight leg raising test and the size or nature of the abnormal tissue in the spinal canal postoperatively could be demonstrated. It was concluded that early postoperative MRI after lumbar discectomy must be interpreted carefully, and that oedema and scar formation are probable reasons for difficulties in interpretation.
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| 2. |
- Burtscher, I M, et al.
(författare)
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Proton magnetic resonance spectroscopy in brain tumours: clinical applications
- 2001
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 43:5, s. 345-352
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Forskningsöversikt (refereegranskat)abstract
- Parallel to the rapid development of clinical MRI, MR spectroscopy (MRS) has, after starting as an analytical tool used in chemistry and physics, evolved to a noninvasive clinical examination. Most common neuroradiological diagnostic indications for MRS are functional inborn errors, neonatal hypoxia, ischaemia, metabolic diseases, white matter and degenerative diseases, epilepsy, inflammation, infections and intracranial neoplasm. Compared to CT and MRI, well-established morphological diagnostic tools, MRS provides information on the metabolic state of brain tissue. We review the clinical impact of MRS in diagnosis of tumours and their differentiation from non-neoplastic lesions.
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| 3. |
- Cronqvist, Mats, et al.
(författare)
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Diffusion and perfusion MRI in patients with ruptured and unruptured intracranial aneurysms treated by endovascular coiling: complications, procedural results, MR findings and clinical outcome.
- 2005
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 47:11, s. 855-873
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Tidskriftsartikel (refereegranskat)abstract
- Our purpose was to evaluate treatment safety as well as complications frequency and management in endovascular coiling of intracerebral aneurysms using MR diffusion and perfusion imaging. In this prospective study, 77 MR examinations were performed in conjunction with 43 procedures in 40 patients, 14 patients presented with ruptured and 26 with unruptured aneurysms. Mean time interval between treatment and post-procedure MRI was 29 and 25 h for the ruptured and unruptured aneurysm group, respectively. Peri-procedural complications, including five major events and five minor transient events, occurred in 10/43 procedures (23%), necessitating thrombolytic therapy in two patients and angioplasty in one, all three within the unruptured aneurysm group. Fifty-one new lesions were found on post-treatment DWI and 47 of them were regarded as of ischemic origin. Most lesions were small (< 3 mm), ipsilateral to the treated aneurysm and asymptomatic (37/40 patients). Sixty-seven percent of the lesions were found in the ruptured and 33% in the unruptured aneurysm group. The ischemic lesions did occur more frequently in patients treated for aneurysm of large neck size and according to the remodelling technique. The overall morbidity and mortality rates were 14.6 and 7.3% whereas morbidity and mortality rates related to the technique were only 2.6 and 0%, respectively. Silent embolism seems to be more common than clinically evident and partially related to patient presentation, heparinazation and treatment strategy. The capability to depict early complications and analyse their potential causes by using MR with DWI has been of great importance in our modification and improvement of therapeutic protocols, evaluations and strategies.
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| 4. |
- Cronqvist, Mats, et al.
(författare)
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Diffusion- and perfusion-weighted MRI in therapeutic neurointerventional procedures
- 2001
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 43:8, s. 662-671
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Tidskriftsartikel (refereegranskat)abstract
- We describe three patients in whom we used MRI, including diffusion- and perfusion-weighted imaging (DWI, PWI) in conjunction with endovascular therapy. Two had intracranial aneurysms and one an arteriovenous malformation (AVM). The aneurysms were treated by coil embolisation or detachable balloons for proximal artery occlusion; the AVM was obliterated by intranidal glue injection. All patients had transient or permanent neurological deficits after treatment. The MRI techniques and interventional procedures are described and the DWI and PWI patterns found are correlated with the clinical features. We discuss how the information gained from MRI may increase our understanding of procedure-related complications and its potential impact on our therapeutic interventions, in order to prevent or limit the clinical consequences of such events.
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| 5. |
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| 6. |
- Geijer, Bo, et al.
(författare)
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Persistent high signal on diffusion-weighted MRI in the late stages of small cortical and lacunar ischaemic lesions
- 2001
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 43:2, s. 115-122
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Tidskriftsartikel (refereegranskat)abstract
- Diffusion-weighted imaging (DWI) is very sensitive to early brain infarcts. However, the late stages have been insufficiently studied. Infarcts in small vessel disease are often multiple and of different ages, and differentiation between new and old lesions might be difficult. We have therefore studied the change with time in DWI of small (< 3 ml) ischaemic lesions. We imaged 21 patients with an acute lacunar syndrome and a lesion visible on early DWI. They all had three MRI examinations 12-58 h (early), 7-16 and 54-144 days after the onset of stroke; 10 patients with high DWI signal on the third examination had a fourth examination 12-28 months after the stroke. MRI was performed at 1.5 T, using echo-planar DWI with 7 b-values from 0 to 1200 x 10(6) s/m2 and conventional T2-weighted imaging. After 7-16 days 18 of 21 lesions gave high signal on DWI, and 12/16 measurable lesions had a decreased apparent diffusion coefficient (ADC). After 54-144 days ten lesions still gave high DWI signal and two still had an ADC below normal. On the fourth examination there was no remaining high DWI signal and all ADC were higher than normal.
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| 7. |
- Geijer, Bo, et al.
(författare)
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The value of b required to avoid T2 shine-through from old lucunar infarcts in diffusion-weighted imaging
- 2001
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 43:7, s. 511-517
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Tidskriftsartikel (refereegranskat)abstract
- Multiple small infarcts of different ages are common in small-vessel disease. Diffusion-weighted imaging (DWI) is a powerful method for discriminating new from chronic lesions. This can be done on the diffusion-weighted images provided that b is sufficiently high. Our purpose was to determine that critical value of b. We reviewed DWI from a previous study of acute, mainly lacunar strokes, and selected 18 old lacunar infarcts, well defined on uncoded images with b 0 s/m2 (i. e., T2-weighted images) but invisible on DWI with b 1,200 x 10(6) s/m2. We used a 1.5 tesla imager and single-shot echo-planar technique. We had seven separate acquisitions with echo time 123 ms and b in steps between 0 and 1,200 x 10(6) s/m2. Two neuroradiologists blinded to the selection of lesions carried out two different lesion-detection procedures, thereby testing each lesion four times, giving a total of 72 tests of b values. The results were consistent, indicating a level for detection of 800 x 10(6) s/m2 in two tests, 400-600 x 10(6) s/m2 in 65 tests and at lower values in the remainder. For imagers up to 1.5 tesla, at long repetition times and an echo time up to 120 ms T2-shine through of old lacunar infarcts can be avoided using b of 1,000 x 10(6) s/m2.
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| 8. |
- Holtås, Stig, et al.
(författare)
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A ring-enhancing metastasis with central high signal on diffusion-weighted imaging and low apparent diffusion coefficients
- 2000
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 1432-1920 .- 0028-3940. ; 42:11, s. 824-827
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Tidskriftsartikel (refereegranskat)abstract
- Diffusion-weighted imaging (DWI) has been reported to be useful in the differential diagnosis between abscesses and cystic or necrotic tumours. However, experience is still limited and the true sensitivity and specificity remain to be determined. Our purpose is to describe a ring-enhancing metastasis of adenocarcinoma with a DWI pattern similar to that reported for abscesses. The tumour had a diameter of 1.5 cm and give signal from its centre similar to that of normal brain on T1-weighted images, whereas it was increased on T2-weighted images, and surrounded by a low signal ring, suggesting a capsule. The signal was high on DWI and the apparent diffusion coefficient (ADC) was low (0.55 x 10(-3) mm2/s). The findings were misinterpreted as representing an abscess in the early capsule-formation stage, but the signal pattern probably represented early tumour necrosis with intracellular oedema, but without liquefaction. Findings on DWI during the early capsule formation stage in abscesses and early tumour necrosis are probably similar and must be interpreted with caution.
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| 9. |
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| 10. |
- Holtås, Stig, et al.
(författare)
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MRI in acute transverse myelopathy
- 1993
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Ingår i: Neuroradiology. - 1432-1920. ; 35:3, s. 221-226
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Tidskriftsartikel (refereegranskat)abstract
- The MRI examinations of seven patients with acute transverse myelopathy (ATM) were analysed. The patients were examined 2-5 times during the course of their disease with short and long TR/TE spin-echo sequences in the sagittal projection. A previous history of autoimmune disorder and/or signs of infection at the onset of ATM were present in all cases. Cerebrospinal fluid analysis showed local synthesis of immunoglobulin in the nervous system in three cases and signs of infectious myelitis in one. During the acute phase four patients had local enlargement of the cord and all had increased signal on long TR/TE sequences. The outcome was grave in the majority of patients and there seemed to be a correlation between the degree of cord enlargement, persistence of increased signal intensity and limited recovery. Atrophy and remaining high signal intensity were noted on late MRI in patients with poor outcome. In one patient with probable anterior spinal artery occlusion, cavitation of the cord was seen.
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