Biomedical subjects
Publications and source records attributed to Y S Cordoliani.
We report the case of a 25-year-old man who presented a fibrous pseudotumor of the epididymis, a rare focal location of nodular and diffuse fibrous proliferation. We provide the ultrasonographic and MRI findings with pathologic correlation.
This article considers the various mechanisms of brain injury and specifies the most efficient radiologic technique for assessing patients, depending on clinical presentation. The brain injuries include either extracerebral and intracerebral lesions. The former require rapid diagnosis and therapy and the latter determine management in an intensive therapy, unit and outcome. Standard X-rays are obsolete. The CT, rapidly performed, is the most relevant imaging procedure for surgical lesions. Cortical contusions and diffuse axonal injuries are underestimated by CT and best depicted by MRI. Only late MRI has a strong correlation with neuropsychological outcome. In terms of prognosis, MRI needs to be evaluated. The indications include: a) unstable neurological status: CT; b) moderate head injury: CT may help to decide hospital admission; c) severe head injury: initial CT may be followed by MRI; d) long-term consequences: MRI. Special Indications: a) angio-MRI: suspicion of vascular lesion; b) CT with thin slices and bone window: depressed skull fracture; c) teleradiology (image transfer): to decide a patient transport from a peripheral hospital to a neurosurgical centre. In conclusion, CT remains the first-line examination to detect immediately life-threatening lesions. MRI is the examination of choice for full assessment of brain lesions.
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The purpose was to incorporate preoperative functional imaging data into anatomic data of operative microscope for neurosurgical procedures of patients suffering from lesions contiguous to eloquent brain areas. The day before surgery, patients bearing scalp markers underwent fMRI, just before anatomical contrast-enhanced MR images. FMRI data analysis were realised using a t test (p<0.0001). The resulting functional-anatomical images were downloaded onto a surgical neuronavigation computer in order to outline tumoral target and functional areas. At surgery, cortical stimulation has been used to confirm functional data. Functional image-guided surgery of lesions abutting functional cortex can be safely performed.
PURPOSE: To evaluate residual activity in the sensorimotor cortex of the lower limbs in paraplegia. METHODS: 5 patients suffering from a complete paralysis after traumatic medullar lesion (ASIA=A). Clinical evaluation of motility and sensitivity. 1. Control functional MR study of the sensorimotor cortex during simultaneous movements of hands, imaginary motor task and passive hands stimulation. 2. Concerning the lower limbs, 3 fMRI conditions: 1-patient attempts to move his toes with flexion-extension, 2-mental imagery task of the same movement, 3-peripheral passive proprio-somesthesic stimulation (squeezing) of the big toes. RESULTS: Activations were observed in the primary sensorimotor cortex (M1), premotor regions and in the supplementary motor area (SMA) during movement and mental imaginary tasks in the control study and during attempt to move and mental imaginary tasks in the study concerning the lower limbs. Passive somesthesic stimulation generated activation posterior to the central sulcus for 2 patients. CONCLUSION: Activations in the sensorimotor cortex of the lower limbs can be generated either by attempting to move or mental evocation. In spite of a clinical evaluation of complete paraplegia, fMRI can show a persistence of sensitive anatomic conduction, confirmed by Somesthesic Evoked Potentials.
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Helical CT is the imaging modality that delivers the highest exposure to patients. For each acquisition, the average radiation dose is between 20 and 30 mGy. This dose can potentially be reduced by decreasing the intensity or voltage and by increasing the pitch. Helical data can be reformatted to obtain images with smaller increment or multiplanar reconstructions, hence reducing the need for additional acquisitions. Hardware and software devices designed for dose reduction must be systematically used. Operators of CT units should be aware of the radiation dose delivered with helical CT and must carefully assess the need of each additional acquisition. Obsolete protocols such as angulation of the gantry for lumbar CT, which increases patient exposure, should no longer be used. Rational use of helical CT decreases radiation exposure and is faster, whereas improper use increases radiation exposure without added benefit.
Helical computed tomography is the main source of ionizing radiation delivery in diagnostic radiology. For each series, average radiation dose is between 20 and 30 mGy. This dose can potentially be reduced by decreasing intensity or voltage and by increasing pitch. Helical acquisition allows reformating of images with smaller increment or different obliquity, and avoids additional irradiation. Hardware and software devices designed for dose reduction must be systematically used. Users of CT systems should be aware of radiation dose delivered with CT and must carefully assess the need of each additional acquisition. Obsolete habits, as gantry tilting for lumbar CT, which increases patient exposure, must be given up. Rational use of helical CT decreases radiation exposure and gains time, whereas thoughtless use increases radiation exposure without real benefit.
We review the main cerebral parasitic diseases, with emphasis on the most frequently encountered in Europe.
In three cases of cerebral malaria, MR imaging disclosed either cortical infarcts (one case) or hyperintense areas of white matter (two cases) on T2-weighted and fluid-attenuated inversion-recovery sequences. These white matter abnormalities were, in one case, sharply limited, symmetrical, hyperintense, and unenhanced; in the other case, they were diffuse, hyperintense, and had a more limited focus. The diffuse hyperintensity was probably due to edema, whereas focal lesions were probably associated with gliosis.
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OBJECTIVE: To assess the value of high resolution 2D fast spin echo T2-weighted sequence (HR 2D-FSE T2w) for evaluating the internal auditory meatus (IAM) in patients with asymetric or unilateral sensorineural hearing loss, vs. gadolinium-enhanced T1-weighted (T1w) sequence; to suggest a screening protocol to exclude the diagnosis of acoustic neuroma in a patient with isolated unilateral sensorineural hearing loss. MATERIALS AND METHODS: One-hundred ten patients with suspected acoustic neuroma were evaluated with 1.5 T MRI system. The protocol included axial images focused on the IAM: HR 2D-FSE T2w images (4000/63, ETL = 16, 3-mm sections with 1.5 mm overlap, 18 FOV, 512 x 384 matrix) and gadolinium-enhanced T1w images (600/23, 3-mm sections, 18 FOV, 256 x 192 matrix). Two criteria for normality of the HR 2D-FSE T2w examination are defined: high homogeneous signal of the cerebellospinal fluid (CSF) and linear low signal of the nerves visible throughout the IAM. RESULTS: Overall results show no false-negative and six false-positive with HR 2D-FSE T2w sequences vs. gadolinium-enhanced T1w sequences. The sensitivity of HR 2D-FSE T2w sequences is 100%, specificity 93%, and negative preditive value 100%: normal images using HR 2D-FSE T2w sequence can rule out the diagnosis of acoustic neuroma. CONCLUSION: Using this protocol we can exclude the diagnosis of acoustic neuroma in case of normal HR 2D-FSE images and no additional gadolinium-enhanced T1w sequence is necessary. This protocol might reduce examination time, must promote recourse to MRI in the event of clinical suspicion of acoustic neuroma, and also enables savings by proposing MRI examination as a first-line exam.
OBJECTIVE: In 1988, the neurosurgeons and neuroradiologists at the Val-de-Grâce hospital decided to create a stereotaxis site using advanced medical imaging date (CT-scan or MRI). METHODS: Two MRI machines and on CT unit were linked to a network (ETHERNET) available for radiologists in 1989. Neurosurgeons adapted stereotaxis sites using Leksell, Fisher and CRW software for MRI. A data processing program recognizing these sites was developed for stereotaxic biopsies based on MRI data. The network was extended in 1992 to the radiotherapy unit for multiple beam stereotaxic irradiations. Finally from 1994, when a computer-guided microscope (Zeiss MKM) was installed, nearly all neurosurgical procedures were conducted under stereotaxic conditions. RESULTS: Since 1989, approximately 900 computer-guided stereotaxic biopsies have been performed with precision in the millimeter range. Since 1994, the Zeiss MKM microscope has been used for 120 computer-guided procedures with the frameless stereotaxic technique guided from landmarks on the outer cranium or attached to the scalp. Mean precision obtained with landmarks was 1.2 mm and 2.8 mm with scalp markers. CONCLUSION: These techniques of computer-assisted neurosurgery based on advanced medical imaging techniques has been revolutionary for surgical approach to intracranial and intracerebral diseases. Smaller assess routes and precise pathways allow an approach to formerly inoperable lesions with minimal risk.
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