| 1. |
- Alemany, Montserrat, et al.
(författare)
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Coexistence of microhemorrhages and acute spontaneous brain hemorrhage : correlation with signs of microangiopathy and clinical data
- 2006
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Ingår i: Radiology. - : Radiological Society of North America (RSNA). - 0033-8419 .- 1527-1315. ; 238:1, s. 240-7
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To evaluate prospectively with magnetic resonance (MR) imaging the coexistence of microhemorrhages (MHs) in white patients with acute spontaneous intraparenchymal hemorrhage (IPH) and acute ischemic stroke and to study the association with imaging findings of microangiopathy and various clinical data. MATERIALS AND METHODS: Before examinations, informed consents were signed by either the patient or a relative. The study was carried out with the approval of the local ethics committee. MR imaging was performed in 90 patients with acute stroke: 45 with acute spontaneous IPHs (24 men and 21 women; median age, 65 and 68 years, respectively) and 45 age-matched control subjects without intracranial hemorrhages (26 men and 19 women; median age for both, 67 years), as determined at computed tomography. MR imaging included transverse T1- and T2-weighted spin-echo, transverse fluid-attenuated inversion recovery, transverse and coronal T2*-weighted gradient-echo, and, in 50 patients, diffusion-weighted sequences. Presence of MHs and signs of microangiopathy, such as T2 hyperintensities or lacunae, were recorded in the white and deep gray matter. The relationships between MH and IPH and between MH and T2 hyperintensities were analyzed by means of regression analysis. Different clinical features, such as arterial hypertension or diabetes, were registered and correlated with the image findings by means of regression analysis. RESULTS: MHs were found in 64% of patients with IPH (29 of 45) and 18% of control subjects (eight of 45). A statistically significant relationship between MH and IPH was determined (P < .001). Among the 29 patients with IPH and MH, 24 (83%) had T2 hyperintensities and 13 (45%) had lacunae; among the 16 patients without MH, seven (44%) had T2 hyperintensities and three (19%) had lacunae. A relationship between MH and occurrence and extent of T2 hyperintensities was also identified (P < .001). There was no clear relationship with the clinical data studied. CONCLUSION: The results support a correlation between the presence of imaging signs of cerebral microangiopathy, clinically silent MHs, and acute IPHs. RSNA, 2006.
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| 2. |
- Alemany Ripoll, Montserrat, et al.
(författare)
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Detection and appearance of intraparenchymal haematomas of the brain at 1.5 T with spin-echo, FLAIR and GE sequences : poor relationship to the age of the haematoma
- 2004
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Ingår i: Neuroradiology. - : Springer Science and Business Media LLC. - 0028-3940 .- 1432-1920. ; 46:6, s. 435-43
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Tidskriftsartikel (refereegranskat)abstract
- The specific appearance of blood related to time at T1- and T2-weighted spin-echo (SE) sequences is generally accepted; thus, these sequences are classically used for estimating the age of haematomas. Magnetic resonance imaging at 1.5 T, including T1- and T2-weighted SE fluid-attenuated inversion recovery (FLAIR) and T2*-weighted gradient-echo (GE) sequences, was performed on 82 intraparenchymal haematomas (IPHs) and 15 haemorrhagic infarcts (HIs) in order to analyse the appearance at different stages and with different sequences, and to investigate how reliably the age of hematomas can be estimated. The IPHs had been previously detected by CT, were spontaneous ( n=72) or traumatic ( n=10) in origin and were of different sizes (2 mm to 7 cm) and ages (from 7.5 h to 4 years after acute haemorrhagic event). The age of the lesion was calculated from the moment when clinical symptoms started or the traumatic event occurred. The 15 patients with HIs were patients with ischaemic stroke in whom there was either a suspicion of haemorrhagic transformation on CT, or haemorrhage was detected as an additional finding on MR performed for other indications. Patients with conditions that could affect the SI of blood, such as anticoagulant therapy or severe anaemia, were excluded. The signal intensity pattern of the lesions was analysed and related to their ages without prior knowledge of the clinical data. All lesions were detected with T2*-weighted GE. T1-weighted SE missed 13 haematomas and T2-weighted SE and FLAIR sequences missed five. Haemorrhagic transformation was missed in three infarcts by T1-, T2-weighted SE and FLAIR. The signal pattern on FLAIR was identical to that on T2-weighted SE. For all sequences, a wide variety of signal patterns, without a clear relationship to the age of the haematomas, was observed. There was a poor relationship between the real MR appearance of IPHs and the theoretical appearance on SE sequences. T2*-weighted GE was effective for detecting small bleedings but was not useful for estimating the age of a lesion. The FLAIR does not provide any more information than T2-weighted SE.
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| 3. |
- Alemany Ripoll, Montserrat, et al.
(författare)
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Experimental intracerebral and subarachnoid/intraventricular haemorrhages
- 2002
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Ingår i: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 43:5, s. 464-73
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To compare the detectability of small experimental intracranial haemorrhages on MR imaging at 0.5 T and 1.5 T, from hyperacute to subacute stages. MATERIAL AND METHODS: 1 ml of autologous blood was injected into the brain of 15 rabbits to create intraparenchymal haematomas. Since the blood partially escaped into the cerebrospinal fluid (CSF) spaces, detectability of subarachnoid and intraventricular blood was also evaluated. MR imaging at 0.5 T and at 1.5 T was repeated up to 14 days, including T1-, proton density- and T2-weighted (w) spin-echo (SE), FLAIR and T2*-w gradient echo (GE) pulse sequences. The last MR investigation was compared to the formalin-fixed brain sections in 7 animals. RESULTS: The intraparenchymal haematomas were best revealed with T2*-w GE sequences, with 100% of sensitivity at 1.5 T and 90-95% at 0.5 T. Blood in the CSF spaces was significantly (p < 0.05) better detected at 1.5 T with T2*-w GE sequences and detected best during the first 2 days. The next most sensitive sequence for intracranial blood was FLAIR. SE sequences were rather insensitive. CONCLUSION: 1.5 T equipment is superior to 0.5 T in the detection of intracranial haemorrhages from acute to subacute stages. T2*-w GE sequences account for this result but other sequences are also needed for a complete examination.
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| 4. |
- Alemany Ripoll, Montserrat, et al.
(författare)
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MR follow-up of small experimental intracranial haemorrhages from hyperacute to subacute phase
- 2002
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Ingår i: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 43:1, s. 2-9
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To compare pulse sequences in revealing intracranial bleeding from the hyperacute to subacute phase. MATERIAL AND METHODS: We injected 0.3-1 ml of autologous blood into the brain of 8 rabbits. MR imaging was performed immediately after haematoma creation and then at determined intervals up to 9-12 days. All images were analysed by two observers. After the last MR investigation, the brain was fixed in formalin. The last MR images were compared to the fixed brain sections and to the histologic findings. RESULTS: T2*-weighted GE sequences, both conventional spoiled and echoplanar sequences, revealed the intraparenchymal haematomas as hypointensities in all but 1 case, which was negative from the second day onward (a rabbit with 0.3 ml blood injected). The signal patterns remained unchanged during the follow-up. The haematoma sizes and shapes corresponded well to gross pathology. Blood in the cerebrospinal fluid (CSF) space was detected with T2*-weighted GE sequences in a great majority of the examinations during the first 2 days. The cases with the smallest injected volume of blood were negative. SE sequences were rather insensitive. The FLAIR sequence often revealed blood in CSF spaces but not in the brain. CONCLUSION: T2*-weighted GE sequences are capable of revealing very small intraparenchymal haemorrhages from the hyperacute to the subacute phase, and blood in CSF spaces during at least the first 2 days.
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| 5. |
- Alemany Ripoll, Montserrat
(författare)
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MRI Diagnosis of Intracranial Hemorrhage : Experimental and Clinical Studies
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this work was to improve the diagnosis of intracranial hemorrhage with MRI, using, among others, T2*-w GE sequences. Various sequences were tested in rabbits at two magnetic field strengths. Then, the most effective technique was applied to stroke patients. Experimental studies: The MR detectability of small experimental haematomas in the brain and of blood in the cerebrospinal fluid (CSF) spaces of 30 rabbits was evaluated. MRI examinations were performed at determined intervals. The last MR images were compared to formalin fixed brain sections and, in 16 rabbits, also to the histological findings. T2*-weighted GE sequences revealed all the intraparenchymal haematomas at 1.5 T, appearing strongly hypointense. Their signal patterns remained unchanged during the follow-up. Blood in the CSF spaces was best detected at 1.5T with T2*-weighted GE sequences during the first 2 days. FLAIR and SE sequences were rather insensitive.Clinical studies: MR examinations were performed at 1.5T, including T1- and T2-w SE, FLAIR and T2*-w GE sequences. In the first clinical study, 66 intraparenchymal hematomas (IPH) of different sizes and ages were examined. T2*-w GE sequence was the most sensitive. On all the sequences, we found a big variety of signal patterns, without a clear relationship to the age of the hematomas. In a second clinical study, MR examinations were performed to 83 patients with acute stroke: 43 presented acute IPH and 40 were used as controls. Old microhemorrhages (OMHs) were found in 60% of the patients with IPH, and in 15% of the controls. Conclusion: T2*-weighted GE sequences are capable of revealing very small intraparenchymal hemorrhages at any stage, and blood in CSF spaces during at least the first 2 days. The age of IPHs cannot reliably be estimated with MRI. We have found a correlation between the presence of OMHs and acute intraparenchymal hematomas.
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| 6. |
- Cornefjord, Michael, et al.
(författare)
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Posterior atlanto-axial fusion with the Olerud cervical fixation system for odontoid fractures and C1-C2 instability in reumathoid arthritis
- 2003
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Ingår i: European spine journal. - : Springer Science and Business Media LLC. - 0940-6719 .- 1432-0932. ; 12:1, s. 91-96
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Tidskriftsartikel (refereegranskat)abstract
- In posterior C1-C2 fusion, traditional wire fixation gives poor stability. The bone quality is often insufficient to provide the competent structural bone graft that is required, and the introduction of sublaminar wires is somewhat dangerous. The stability is markedly improved by adding transarticular screws, but the drawbacks of structural bone graft and sublaminar wires remain. The C1 claw of the Olerud Cervical Fixation System improves C1-C2 fixation without relying on structural bone graft or compromising the spinal canal. The aim of this study was to evaluate radiological healing and possible complications in a consecutive series of C1-C2 fusions from our department operated with the C1 claw device. Twenty-six patients (14 women) with a mean age of 73 (range 37-93) years were included. The diagnoses were odontoid fracture in 18 patients, rheumatoid instability in 6, and odontoid non-union and os odontoideum in 1 each. The patients were followed clinically and with plain radiographs for an average of 15 (range 3-27) months. There were no neurological or vascular complications, and no secondary displacements or reoperations in the series. Twenty patients followed for 6-27 months were radiographically healed. Six patients died from unrelated causes 1-38 months postoperatively. Three of these patients had no radiographs later than the postoperative control, one had a healed odontoid fracture but resorbed bone graft at 8 months, while the remaining two patients were not healed, but showed no signs of healing disturbance at the time of death. On the basis of the findings of this study, posterior C1-C2 fusion with the Olerud Cervical Fixation System seems promising. No serious complications related to the surgical procedure were encountered. The stability of the implant obviates the use of a solid bone block as a graft and still allows a high frequency of fusion healing.
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| 7. |
- Jonsdottir, Björg, et al.
(författare)
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Validation of F-18-FDG PET/MRI and diffusion-weighted MRI for estimating the extent of peritoneal carcinomatosis in ovarian and endometrial cancer : a pilot study
- 2021
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Ingår i: Cancer Imaging. - : BioMed Central (BMC). - 1740-5025 .- 1470-7330. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- Background: The extent of peritoneal carcinomatosis is difficult to estimate preoperatively, but a valid measure would be important in identifying operable patients. The present study set out to validate the usefulness of integrated F-18-FDG PET/MRI, in comparison with diffusion-weighted MRI (DW-MRI), for estimation of the extent of peritoneal carcinomatosis in patients with gynaecological cancer.Methods: Whole-body PET/MRI was performed on 34 patients with presumed carcinomatosis of gynaecological origin, all scheduled for surgery. Two radiologists evaluated the peritoneal cancer index (PCI) on PET/MRI and DW-MRI scans in consensus. The surgeon estimated PCI intraoperatively, which was used as the gold standard.Results: Median total PCI for PET/MRI (21.5) was closer to surgical PCI (24.5) (p = 0.6), than DW-MRI (median PCI 20.0, p = 0.007). However, both methods were highly correlated with the surgical PCI (PET/MRI: beta = 0.94 p < 0.01, DW-MRI: beta = 0.86, p < 0.01). PET/MRI was more accurate (p = 0.3) than DW-MRI (p = 0.001) when evaluating patients at primary diagnosis but no difference was noted in patients treated with chemotherapy. PET/MRI was superior in evaluating high tumour burden in inoperable patients. In the small bowel regions, there was a tendency of higher sensitivity but lower specificity in PET/MRI compared to DW-MRI.Conclusions: Our results suggest that FDG PET/MRI is superior to DW-MRI in estimating total spread of carcinomatosis in gynaecological cancer. Further, the greatest advantage of PET/MRI seems to be in patients at primary diagnosis and with high tumour burden, which suggest that it could be a useful tool when deciding about operability in gynaecological cancer.
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| 8. |
- Ripoll, Montserrat Alemany, et al.
(författare)
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MR detectability and appearance of small experimental intracranial hematomas at 1.5 T and 0.5 T : A 6-7-month follow-up study
- 2003
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Ingår i: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 44:2, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the detectability and appearance of small experimental intracranial hemorrhages on MR at 0.5 T and 1.5 T in a long-term follow-up. MATERIAL AND METHODS: Autologous blood (1 ml) was injected into the brain of 7 rabbits to create intraparenchymal hematomas. The injected blood leaked partially into the cerebrospinal fluid (CSF) spaces. MR imaging at 0.5 T and 1.5 T were performed immediately before and after hematoma creation, at 2 weeks and monthly up to 6 or 7 months using T1-, proton density- and T2-weighted (w) spin-echo (SE), FLAIR and T2*-w gradient echo (GE) pulse sequences. RESULTS: Blood was detected both in the brain and in the CSF spaces of all animals during the first hours after hematoma creation at 1.5 T. In the last examination after 6-7 months, the T2*-w GE sequences still showed residues of the intraparenchymal hematomas in all the rabbits at 1.5 T, but the signal pattern was not specific for the age of the hematomas. SE and FLAIR sequences were insensitive. The histopathology revealed iron deposits in all brains. CONCLUSION: Residues of small intraparenchymal hematomas can be seen for months with T2*-w GE sequences on brain MR imaging at 1.5 T. The age of the microhematomas cannot be estimated with MR imaging.
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