PubMed Health⌕ Search

Biomedical subjects

I Anno

Publications and source records attributed to I Anno.

At least 19 recordsLinked to original sources
PubMed2003

Perfusion-weighted MRI of spinal dural arteriovenous fistula.

A 72-year-old woman was admitted with rapidly progressive paraplegia and sphincter disturbance. T2-weighted images of the thoracic spine showed intramedullary high signal with flow voids suggesting dilated medullary veins. Conventional spinal angiography demonstrated a dural arteriovenous fistula draining into perimedullary veins. Perfusion-weighted MRI demonstrated a prolonged mean transit time and increased blood volume in the high-signal area. The loss of normal perfusion gradient and venous hypertension and were thought to produce these differences. The time-to-peak was almost identical in the high-signal and isointense areas, although the bolus of contrast medium arrived earlier in the former. Arteriovenous shunting was thought to cause faster inflow. These changes may have resulted in increased blood volume in the spinal cord. The high signal has been attributed to oedema due to venous congestion, but there has been no histological confirmation. Perfusion MRI in this case supports this hypothesis.

Aged↗
PubMed2003

Intraoperative angiography in the surgical treatment of cerebral arteriovenous malformations and fistulas.

BACKGROUND: The role of intraoperative angiography in the surgical treatment of cerebrovascular malformations remains controversial. The authors report on their experiences with intraoperative angiography in a series of 20 cases with cerebrovascular malformation to determine whether the use of intraoperative angiography has a favorable impact on the surgical treatment of cerebrovascular malformations. METHODS: Intraoperative angiography was performed in the surgical resection of arteriovenous malformation in 18 patients and in the surgical obliteration of arteriovenous fistula in 2 patients. The incidence of unexpected findings, such as residual nidus, demonstrated by intraoperative angiography was determined. FINDINGS: High-quality subtraction images were obtained by intraoperative angiography in every case and the findings prompted an additional procedure in 1 case that displayed an unexpected residual nidus (5.6%). There were no complications from the intraoperative angiography procedure. INTERPRETATION: Intraoperative assessment of technical results prior to wound closure offers the neurosurgeon the opportunity to resect or obliterate a vascular malformation completely, obviating a second operation.

Adolescent↗
PubMed2002

Chronological change of brain abscess in (1)H magnetic resonance spectroscopy.

We studied chronological magnetic resonance spectral changes in brain abscesses before and after medical and/or surgical treatment. We examined five patients with MRI imaging and (1)H magnetic resonance spectroscopy (MRS) on two or more occasions, using two volume-of-interest patterns, and saw chronological changes related to the evolution of the abscess. A spectrum specific for brain abscess was found in three of the five cases, while two showed a single lactate peak in the first study. In two cases, phenylalanine or alanine appeared in the second study. We observed the disappearance of the specific spectra and a single lactate peak following surgery. Only one patient showed different spectra in different volume of interest.

Adolescent↗
PubMed2001

Intracranial hypotension.

The authors present the case of a 55-year-old man suffering from intractable spontaneous intracranial hypotension, in whom conservative treatment with 19 weeks of bed rest was not effective. In this period the patient twice underwent surgery for bilateral chronic subdural hematoma, a complication of spontaneous intracranial hypotension. Conventional radionuclide cisternography, magnetic resonance imaging, and computerized tomography myelography did not demonstrate cerebrospinal fluid (CSF) leakage. Repeated radionuclide cisternography with the patient in an upright position revealed leakage of the tracer at upper cervical levels. Computerized tomography myelography with breath holding also showed CSF leakage of the contrast medium bilaterally at upper cervical levels. The patient underwent surgery, and bilateral C-2 and C-3 spinal nerve root pouches were sealed off from the subarachnoid space with oxidized cellulose cotton and fibrin glue. Epiarachnoid spaces around the root sleeves were also sealed to ensure complete resolution of the CSF leakage. After the surgery, the patient was completely free of the disease. In the case of intractable persistent spontaneous intracranial hypotension, surgical treatment is preferable to long-term conservative management. To identify CSF leakage, radionuclide cisternography with the patient in the upright position is useful. When obvious leakage is encountered, surgical sealing of the lesion should be performed via a subarachnoid approach.

Humans↗
PubMed2000

Distal anterior choroidal artery aneurysm associated with an arteriovenous malformation. Intraoperative localization and treatment.

BACKGROUND: Distal anterior choroidal artery aneurysms are rare. The outcome of patients with distal anterior choroidal artery aneurysms has been poor, and the treatment of such aneurysms is surgically challenging. CASE DESCRIPTION: The authors describe the case of an 8-year-old girl with a ruptured distal anterior choroidal artery aneurysm associated with an arteriovenous malformation (AVM). The patient experienced sudden onset of headache and vomiting. Computed tomography revealed an intraventricular haemorrhage, and cerebral angiography demonstrated an aneurysm arising from the distal portion of the right anterior choroidal artery. The patient also had an AVM in the ipsilateral temporal lobe fed by the branches of the middle cerebral artery. A right frontotemporal craniotomy was performed with the aid of intraoperative angiography to eliminate both the AVM and the aneurysm. Intraoperative angiography was helpful in confirming the complete removal of the AVM and in accurate localization of the small and deeply placed distal anterior choroidal artery aneurysm. Both the AVM and the aneurysm were successfully treated and the patient was discharged without any neurological deficits. CONCLUSION: This case is the youngest reported patient with a distal anterior choroidal artery aneurysm. This report is also the first to describe an association of such an aneurysm with an AVM. The etiology of the aneurysm formation in this case and surgical strategy for deeply placed vascular lesions are discussed.

Aneurysm, Ruptured↗
PubMed2000

Diagnosis of spontaneous intracranial hypotension by using magnetic resonance myelography. Case report.

The authors describe a case of spontaneous intracranial hypotension in which the leakage site was determined by using magnetic resonance (MR) myelography. This technique demonstrated the route of cerebrospinal fluid (CSF) leakage, whereas other methods failed to show direct evidence of leakage. Magnetic resonance myelography is a noninvasive method that is highly sensitive in detecting CSF leakage. This is the first report in which a site of CSF leakage was detected using MR myelography.

Adult↗
PubMed2000

Transcatheter embolization of mycotic aneurysm of the subclavian artery with metallic coils.

Mycotic aneurysms of the subclavian artery are rare. This report describes an experience of 2 rare cases in which transcatheter embolization with metallic coils was performed for the management of these lesions alternative to surgery. Two patients who had been treated with chemotherapy for malignant neoplasms were diagnosed as having mycotic aneurysms of the left subclavian artery. The causes of these lesions were presumed to be the invasion of the arterial wall by the pulmonary abscess in case 1, and wound infection after placement of the reservoir for intraarterial chemotherapy in case 2. In both cases, proximal and distal sites of the aneurysm were embolized with metallic coils. In case 1, the vertebral artery was also embolized with Guglielmi detachable coils to avoid retrograde blood flow. Both aneurysms were completely occluded by a single embolization. In case 1, although weakness and paresthesia of the left hand remained, lethal hemoptysis due to aneurysmal fistulization to the lung parenchyma ceased. In case 2, no neurological deficit except for mild paresthesia in the left thumb had been observed. Both patients died of primary disease 10 and 5 months after the procedure. Transcatheter embolization is technically feasible and effective enough to treat the mycotic aneurysm of the subclavian artery even in the situation in which the surgical option seems to be difficult or risky.

Aneurysm, Infected↗
PubMed1999

Early phase adaptations of muscle use and strength to isokinetic training.

The purpose of this study was to investigate the effect of short periods of isokinetic resistance training on muscle use and strength. Seven men trained the right quadriceps femoris muscles (QF) 9 d for 2 wk using 10 sets of 5 knee extensions each day. Isometric and isokinetic torques of QF were measured at six angular velocities. Cross-sectional areas (CSA) of QF were determined from axial images using magnetic resonance imaging (MRI). Transverse relaxation time (T2) and activated area of QF, which represented the area greater than the mean resting T2 + ISD in MR[pixels, were calculated at rest and immediately after repetitive isokinetic knee extensions based on T2-weighted MR images. Muscle fiber types, fiber area, and phosphofructokinase (PFK) activities were determined from biopsies of the vastus lateralis muscle. No changes were found in CSA of QF, muscle fiber types, fiber area, and PFK activities after the training. Isometric and isokinetic peak torques at 60-240 degrees x s(-1) and relative area of QF activated by knee extensions increased significantly after the training. These results suggest that muscle strength increases after short periods of isokinetic resistance training without muscle hypertrophy would be due to increased muscle contractile activity.

Adaptation, Physiological↗
PubMed1999

[Application of a new MR microscope using an independent console system (MRMICS) for biological tissues in vitro].

We studied microscopic MR images of the normal appendix in vitro using a new MR microscope system: MR Microscope using an Independent Console System (MRMICS). The MRMICS was placed in the clinical MR room, and the probe box was fixed on the bed of the 1.5 T clinical MR machine. T1-, T2-, and proton density-weighted images were obtained using spin echo sequences with an in-plane pixel size of 100 x 100 microns. Zonal structures of the appendix were clearly demonstrated with different contrast by different sequences. Therefore, the MRMICS is a useful add-on system for investigating microscopic MR images of biological tissues in vitro.

Appendix↗
PubMed1997

Multishot echoplanar MR imaging of the female pelvis: comparison with fast spin-echo MR imaging in an initial clinical trial.

OBJECTIVE: The purpose of this study was to apply multishot echoplanar MR imaging (EPI) to the female pelvis and compare image quality with that of fast spin-echo MR imaging. SUBJECTS AND METHODS: Twenty-one patients with suspected pelvic disease and five healthy female volunteers were prospectively examined. MR imaging was obtained using an EPI-capable 1.0-T imager and a pelvic phased-array coil. Axial EPI and fast Spin-echo sequences were obtained at identical image locations in each patient and volunteer. Spin-echo EPI images were obtained using a multishot number of 16. Acquisition time for each EPI sequence was 2 min 10 sec. Fat-suppressed T2-weighted fast spin-echo images were obtained in 2 min 12 sec. Paired EPI and fast spin-echo MR images were independently evaluated by three reviewers. RESULTS: Delineation of the perivaginal and parametrial venous plexus on EPI was rated superior to the fast spin-echo images in 62 (77%) of 81 cases. On EPI, uterine zone anatomy and ovary visualization were judged to be inferior in 44 (56%) of 78 cases and in 18 (33%) of 54 cases, respectively. For delineation of uterine abnormalities, including leiomyoma and adenomyosis, both sequences performed almost equally well. However, ovarian cystic lesions were revealed more precisely by the fast spin-echo sequence. An overall fat-suppression effect was seen on EPI images in 62 (77%) of 81 cases. CONCLUSION: Multishot EPI cannot replace fast spin-echo sequences for imaging the female pelvis; however, because EPI has a potent fat-suppression effect and heavily T2-weighted contrast, EPI sequences can be a valuable adjunct to routine examination.

Echo-Planar Imaging↗
PubMed1997

[Functional MRI employing diazepam; a proposal of neuropharmacological fMRI].

Employing the active benzodiazepine receptor (BZR) ligands, we have used BOLD fMRI to elucidate the effects of these drugs on brain function. The sequential MRI was performed with a 1.5T clinical scanner (Philips GYROSCAN) using a FLASH sequence with the following parameters: TR/TE, 100/45 msec; flip angle, 25 degrees; matrix size, 128*128; 2 averages; for 64 image acquisitions in 32 min. First, 2 mg of diazepam was administrated intravenously at the beginning of the 5th, 15th, 25th, and 35th acquisitions. Then, flumazenil was administrated at the beginning of the 45th (0.2 mg) and 55th (0.3 mg) acquisitions in order to reverse the effect of diazepam. Data processing was made employing Akaike Information Criterion to detect if there were intensity changes after the medication among the trends of intensity changes. Diazepam administration decreased the intensity for a while and flumazenil increased one. In the case of the left frontal glioma with focal epileptogenicity, intensity changes were detected around the tumor. Since the neuronal function consists of the trans-neuronal communications employing neurotransmitters, the result on the modulation of this passage depends on the neuronal function related to the transmitter: gamma-amino butyric acid (GABA) in this instance for the effects of these medications to epilepsy. The change in the local blood flow is the result of the local neuronal activity. Therefore, we speculate that this neuropharmacological functional MR image may reflect the neuronal function related to the GABAegic neurotransmitter system. In addition to elucidating basic neurotransmitter function mechanisms, we believe this technique may have clinical utility in the pre-surgical evaluation of patients with intractable seizure disorders. In this respect, this paper presents a new spectrum of fMRI that is capable to study a part of neurotransmitter function employing the BZR ligands, reversing the effect of the agonist with the competitive antagonist, for the first experience, to propose the neuropharmacological functional MR images to have clinical utility in patients with intractable epilepsy in the interictal state.

Anti-Anxiety Agents↗
PubMed1996

Relationships between fiber composition and NMR measurements in human skeletal muscle.

The purpose of this study was to examine the relationships between the relative contents of phosphocreatine (PCr), inorganic phosphate (Pi), beta-adenosine triphosphate (ATP), and transverse relaxation time (T2) with fiber composition, which determined histochemically in the human skeletal muscle. The vastus lateralis muscles of 28 volunteers were subjected to phosphorus nuclear magnetic resonance (31P NMR) spectroscopy, magnetic resonance imaging (MRI) and muscle biopsy. Muscle fibers were divided into type I and type II fibers using myosin ATPase stain. A wide range of fiber composition levels were observed in the subjects (27.3-74.6% type I fibers). The PCr/ATP, Pi/ATP and (PCr + Pi)/ATP ratios were positively related to the percentage of type II fibers (r = 0.695, p < 0.001, r = 0.429, p < 0.05 and r = 0.773, p < 0.001, respectively). There was no correlation between fiber composition and the PCr/Pi ratio (r 0.127, n.s.) or intracellular pH (r = 0.305, n.s.). Moreover, no correlation was found between T2 and fiber type (r = 0.144, n.s.). These results suggest that 31P NMR can detect the differences in relative content of phosphates between type I and type II fibers, thereby noninvasively evaluating fiber composition in human skeletal muscle.

Adenosine Triphosphate↗
PubMed1996

Brainstem arteriovenous malformation with a pedicle aneurysm treated by endovascular surgery and proton-beam radiosurgery--case report.

A 39-year-old male presented with a small pontine hemorrhage and subarachnoid hemorrhage. Angiography showed a small left pontine arteriovenous malformation (AVM) associated with a small aneurysm on the pedicle feeding the AVM. The pedicle aneurysm was occluded by microcoils. The AVM was then treated by proton-beam radiosurgery. Follow-up angiography 2 years later revealed that the AVM had disappeared completely without neurological deficit. The combination of embolization and proton-beam radiosurgery was curative in this patient with a pontine AVM associated with an aneurysm on the feeding artery, showing that these techniques can be used to treat inoperable vascular lesions safely.

Adult↗
PubMed1995

Control of the rate of phosphocreatine resynthesis after exercise in trained and untrained human quadriceps muscles.

We examined the effect of differences in exercise intensity on the time constant (tc) of phosphocreatine (PCr) resynthesis after exercise and the relationships between tc and maximal oxygen uptake (VO2max) in endurance-trained runners (n = 5) and untrained controls (n = 7) (average VO2max = 66.2 and 52.0 ml.min-1.kg-1, respectively). To measure the metabolism of the quadriceps muscle using phosphorus nuclear magnetic resonance spectroscopy, we developed a device which allowed knee extension exercise inside a magnet. All the subjects performed four types of exercise: light, moderate, severe and exhausting. The end-exercise PCr: [PCr+inorganic phosphate (P(i))] ratio decreased significantly with the increase in the exercise intensity (P < 0.01). Although there was little difference in the end-exercise pH, adenosine diphosphate concentration ([ADP]) and the lowest intracellular pH during recovery between light and moderate exercise, significant changes were found at the two higher intensities (P < 0.01). These changes for runners were smaller than those for the controls (P < 0.05). The tc remained constant after light and moderate exercise and then lengthened in proportion to the increase in intensity (P < 0.05). The runners had a lower tc at the same PCr and pH than the controls, particularly at the higher intensity (P < 0.05). There was a significant correlation between tc and [ADP] in light exercise and between tc and both end-exercise PCr and pH in severe and exhausting exercise (P < 0.05). The threshold of changes in pH and tc was a PCr: (PCr+P(i)) ratio of 0.5. There was a significant negative correlation between the VO2max and tc after all levels of exercise (P < 0.05). However, in the controls a significant correlation was found in only light and moderate exercise (P < 0.05). These findings suggest the validity of the use of tc at an end-exercise PCr: (PCr+P(i)) ratio of more than 0.5 as a stable index of muscle oxidative capacity and the correlation between local and general aerobic capacity. Moreover, endurance-trained runners are characterized by the faster PCr resynthesis at the same PCr and intracellular pH.

Adenosine Diphosphate↗
PubMed1995

Acute effects of exercise on muscle MRI in peripheral arterial occlusive disease.

The midcalf muscles of eight patients who had peripheral arterial occlusive disease were evaluated by exercise MRI before and after bypass surgery or percutaneous transluminal angioplasty. MRI showed a high intensity of these muscles, especially the posterior muscles, after exercise in all patients before intervention. The mean T2 relaxation time was maximal immediately after exercise (tibialis anterior, T2 = 30.8 ms; soleus, T2 = 36.2 ms; gastrocnemius, T2 = 32.8 ms) and then gradually decreased to the preexercise level. The difference in the T2 relaxation time of the soleus between immediately after exercise and at rest was smaller along with improvement of ankle pressure indices (API) after successful intervention (mean T2 difference: 4.91 and 0.72 ms (p < .001); mean API: 0.54 and 0.86 (p < .001) before and after intervention, respectively). The mean resting midcalf T2 relaxation time was significantly higher after intervention (tibialis anterior, T2 = 28.4 and 29.5 ms (p < .05); soleus, T2 = 31.4 and 32.9 ms (p < .05); gastrocnemius, T2 = 29.5 and 31.1 ms (p < .01) before and after intervention, respectively). T2 relaxation time may be a useful quantitative parameter in peripheral arterial occlusive disease as well as in other muscle studies.

Aged↗
PubMed1995

Fat tissue: relationship between chemical shift and magnetization transfer.

The middle calves of the legs of 25 volunteers (12 men and 13 women, aged 18-25 years), as well as phantoms, were examined with 1.5-T magnetic resonance imaging. Gradient-recalled technique was combined with magnetization transfer contrast (MTC) and chemical shift imaging. Periodic oscillation of the MTC effect in fat tissue with variation of echo time was identified at the frequency corresponding to the water-fat chemical shift difference.

Adipose Tissue↗
PubMed1995

[Secondary signs of anterior cruciate ligament tear at MR imaging].

The value of secondary signs of anterior cruciate ligament (ACL) tear was evaluated MR images of 47 knees, 15 with normal, 6 with acutely torn and 26 with chronically torn ACLs confirmed at arthroscopy, were reviewed. Lateral and medial anterior tibial translocations (ATT), posterior cruciate ligament (PCL) bowing ratio and depth of lateral femoral notch (LFN) were measured. The degrees of lateral and medial ATTs and the PCL bowing ratio of the chronically torn ACLs were significantly higher than those of normal ACLs. With cutoff values of 5-mm lateral ATT, 2.5-mm medial ATT and 0.35-PCL bowing ratio, torn ligaments were distinguished from intact ligaments with accuracies of over 80%. Depth of LFN was less sensitive and less accurate. All knees with lateral ATT of 6.4 mm, medial ATT of 3.5 mm, PCL bowing ratio of 0.43 and LFN depth of 1.5 mm or more had torn ACLs. Higher correlations were revealed between lateral ATT and medial ATT, and also between lateral ATT and PCL bowing ratio. Combined criteria of lateral ATT and PCL bowing ratio indicated the highest diagnostic value as a reliable secondary sign of torn ACLs.

Adolescent↗