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P M Ruggieri

Publications and source records attributed to P M Ruggieri.

At least 19 recordsLinked to original sources
PubMed2001

MR imaging in epilepsy.

The advent of MR imaging techniques has immensely improved the ability to evaluate and manage patients with epilepsy. The principles of various MR techniques, the pertinent MRI neuro-anatomic features, and computer based 3D reconstruction post processing methods are discussed. Newer MR-based techniques such as magnetic resonance spectroscopy (MRS) and diffusion weighted imaging (DWI) and their applications and potential usefulness in the evaluation of patients with medically intractable epilepsy are also reviewed.

Brain↗
PubMed1999

Pulse sequences in lumbar spine imaging.

A host of different pulse sequences has been applied to MR imaging of the spine. As the routine evaluation of the spine has become quite standardized, much of the recent development has resulted in minor refinements of this process. This article outlines the pulse sequences commonly used for routine MR imaging of the lumbar spine and provides a critique of the newer sequences and the modifications of the conventional techniques.

Artifacts↗
PubMed1997

Extensive intraosseous gas associated with lymphangiomatosis of bone: report of three cases.

Asymptomatic pneumatosis may be found in patients with lymphangiomatosis of bone. The authors report three cases from three institutions in which development of intraosseous gas in association with lymphangiomatosis of bone was found incidentally at imaging. Soft-tissue emphysema also developed in two cases. In all three cases, intraosseous gas developed after biopsy or surgery in the areas involved with lymphangiomatosis.

Adolescent↗
PubMed1997

Segmented three-dimensional echo-planar flow imaging of the cervical carotid arteries.

PURPOSE: To implement and assess the application of segmented three-dimensional echo-planar MR imaging time-of-flight flow sequences for studying the anatomy of the cervical carotid arteries at 1.5 T. METHODS: The 3-D echo-planar sequences were segmented along the in-plane phase-encoding direction. Echo train lengths (ETLs) of 3 and 5 and signal bandwidths of +/-25, +/-33, and +/-50 KHz were tested along with a conventional (ETL = 1) 3-D MR flow study in six healthy volunteers and in five patients with known arteriosclerotic disease involving the carotid bifurcation as confirmed by conventional angiography. The volunteer data were used to rank the techniques with respect to vessel dimension, vessel/background contrast, and quality by four trained neuroradiologists. For the patient studies, the percentage of stenoses was measured for all MR studies and compared against the conventional angiographic data using the criteria of the North American Symptomatic Carotid Endarterectomy Trial. RESULTS: Using Wilcoxon's test statistic and a significance level of .05, we found that the conventional MR flow examination was better than the segmented techniques and that the segmented techniques with ETL of 3 were superior to their counterparts with ETL of 5. For the ETL of 3 techniques, the high-bandwidth studies were inferior to their lower bandwidth counterparts; however, there was no significant difference between the performance of the medium- and low-bandwidth sequences. The patient data revealed that the segmented techniques consistently overestimated the severity of stenosis; however, in no instance did any of the segmented examinations erroneously indicate the presence of disease. CONCLUSIONS: The reduction in acquisition time and the zero false-positive rate we obtained suggest that segmented 3-D echo-planar MR flow techniques may be used as a screening/locating study for cervical carotid artery disease.

Adult↗
PubMed1995

Hyperintense disks on T1-weighted MR images: correlation with calcification.

PURPOSE: To determine if calcification in the intervertebral disk is associated with hyperintensity on T1-weighted spin-echo magnetic resonance (MR) images. MATERIALS AND METHODS: Sagittal T1-weighted MR images that showed one or more hyperintense intervertebral disks and correlative computed tomographic (CT) scans, plain radiographs, or both, were obtained in 11 patients retrospectively and in 43 patients prospectively. Six patients underwent MR imaging with a fat-suppression technique. Histologic analysis of two disks was performed. RESULTS: Absence of calcification was associated with disks that were isointense relative to normal disks (P < .001), mild to moderate calcification was associated with hyperintense disks (P < .001 and P = .004 [two readers]), and both mild to moderate and marked calcifications were associated with hypointense disks (P < .001). Fat suppression resulted in a decrease in hyperintense signal in two patients. CONCLUSION: The results indicate that hyperintensity is associated with calcification. In the absence of clinical findings that suggest other causes, hyperintense disks are suggestive of degenerative disk disease.

Adult↗
PubMed1995

Cervical radiculopathy.

Cervical radiculopathy refers to any disease process that compromises the cervical nerve roots. This article briefly reviews the normal anatomy of the cervical spine and the clinical presentation of patients with radiculopathy. Emphasis is then placed on the magnetic resonance evaluation of these patients, with focus on degenerative disease, the most common cause of cervical radiculopathy. Dramatic improvements have been appreciated in the magnetic resonance pulse sequences because they have evolved from standard two-dimensional spin echo studies to a combination of two-dimensional spin echo and three-dimensional gradient echo acquisitions. More recently, the gradient echo study has been replaced by hybrid RARE sequences and may soon be supplanted by a three-dimensional version of this sequence with the advent of advanced gradient capabilities of newer magnetic resonance imaging systems.

Cervical Vertebrae↗
PubMed1995

Intracranial aneurysms.

MR angiography provides a rapid, accurate, and extremely flexible noninvasive evaluation of intracranial aneurysms without the cost and risk of conventional angiography. TOF and phase contrast techniques each have specific advantages and disadvantages that can be selectively exploited to optimize aneurysm evaluation. Present indications for MR angiography in aneurysm evaluation include: (1) the presence of incidental findings on a CT or MR examination that suggest the possibility of aneurysm (Figs. 7 and 8), (2) when angiography is contraindicated or when the risk is too high, (3) non-invasive follow-up of patients with known aneurysms, (4) patient refusal of contrast angiography, and (5) evaluation of patients with specific clinical symptoms (i.e., third cranial nerve palsy) or patients with non-specific subacute symptoms in whom an aneurysm might explain the clinical presentation. Although MR angiography certainly can detect aneurysms with a high rate of sensitivity and specificity, detailed decision analyses generally have not supported the overall benefit of this type of screening. Future technical advances as well as advances in the overall understanding of aneurysms may one day prove unequivocally the benefit of MR angiography in screening high-risk patient groups. MR angiography has not yet been clinically evaluated as a tool in the evaluation of acute subarachnoid hemorrhage. Potential obstacles to such an evaluation include the clinical instability of SAH patients, limited spatial resolution of the MR angiography acquisitions, the potential for subarachnoid blood or focal intraparenchymal hematomas to obscure or mimic small aneurysms, and the unreliability of MR angiography in demonstrating vasospasm. Currently these factors continue to provide an integral role for contrast angiography in aneurysm evaluation.

Humans↗
PubMed1994

Occult intracranial aneurysms in polycystic kidney disease: screening with MR angiography.

PURPOSE: To estimate the prevalence, location, and type of cerebral aneurysms in patients with adult polycystic kidney disease (PCKD) and identify associated risk factors. MATERIALS AND METHODS: Ninety-three patients with PCKD were screened for aneurysms with spin-echo parenchymal magnetic resonance (MR) imaging and three-dimensional time-of-flight MR angiography. Prevalence was estimated with the calculated proportions of patients who had aneurysms, adjusted for reported sensitivity and specificity of MR angiography. RESULTS: Thirteen aneurysms, found in 10 patients, were 7 mm or smaller in largest dimension; 11 of these aneurysms were saccular. Intra- and interobserver variabilities were 96%-98%. Conventional arteriograms, obtained in six patients, helped confirm the MR angiographic findings. The best estimates of prevalence of aneurysms were 11.7% in the study group (n = 93) and 25.8% in patients with a family history of aneurysms (n = 6). CONCLUSION: The prevalence of aneurysms in the study group was greater than in the general population. MR angiography is useful in screening for cerebral aneurysms.

Adult↗
PubMed1994

Time-of-flight intracranial MR venography: evaluation of the sequential oblique section technique.

PURPOSE: To implement a time-of-flight MR angiographic technique using the oblique acquisition of thin gradient-echo sections to evaluate the intracranial venous system, and to assess the feasibility of application of this technique in a routine clinical setting. METHODS: The MR angiographic technique consisted of a two-dimensional gradient-echo technique with sequential overlapped sections obtained with an oblique orientation, angled from the sagittal toward the coronal plane. Parameters were evaluated during 41 measurements in 21 healthy volunteers with the section orientation varying from direct sagittal to direct coronal, followed by 64 examinations in 53 patients with an angle of obliquity of 15 degrees to 20 degrees from the sagittal toward the coronal plane. Confirmation of MR venographic findings was through correlation with clinical data and imaging studies. RESULTS: The volunteer data demonstrated optimal visibility of the smaller midline structures with an angle of obliquity of 15 degrees or greater. Patient examinations with this angle demonstrated sinus obstruction or thrombosis (n = 11), sinus compression (n = 2), and apparent sinus stenosis (n = 1). CONCLUSIONS: Oblique-acquisition time-of-flight MR venography seems to provide a rapid, robust technique for intracranial venous examination and can be applied as a useful adjunct to parenchymal MR in the evaluation of suspected venoocclusive disease. This oblique technique demonstrated improved vessel contrast over direct sagittal acquisition, required significantly fewer sections and thus a shorter acquisition time than direct coronal acquisition, and was applied without difficulty in the vast majority of patients in the clinical setting.

Adolescent↗
PubMed1993

Intravenous sedation for MR imaging of the brain and spine in children: pentobarbital versus propofol.

The authors present a prospective study of single-agent pediatric sedation regimens for patients older than 2 years of age undergoing magnetic resonance (MR) imaging of the brain and spine. Thirty patients underwent MR imaging after intravenous administration of pentobarbital in successive boluses of 2.5 mg/kg to a maximum of 7.5 mg/kg. Thirty-one patients received an intravenous bolus followed by continuous infusion of propofol. The dosage schedule for propofol was 2 mg/kg (with supplemental 1 mg/kg boluses) followed by continuous infusion of 6 mg/kg per hour. There was no significant difference in the physiologic response to sedation between the two groups, although the magnitude of the drop in pulse was significantly greater in the group receiving propofol. Three patients receiving propofol experienced transient decreases in oxygen saturation, at variable times over the course of the procedure. However, patients recovered significantly faster from sedation with propofol. While propofol may represent a viable alternative to pentobarbital in selected patients, propofol requires constant physician supervision and meticulous technique.

Brain↗
PubMed1992

Intracranial magnetic resonance imaging.

Magnetic resonance angiography (MRA) is currently being incorporated into the routine MR evaluations of patients with suspected cerebrovascular disease. Currently, MRA serves as a useful adjunct to routine parenchymal spin-echo imaging of the head. Intracranial MRA is predominantly used as a screening test for cerebrovascular disease in situations where the clinical suspicion and/or the patient's physical condition does not warrant a conventional arteriogram. Clinical experience to date suggests that MRA can play a significant role in the evaluation of patients with suspected intracranial aneurysms, arteriovenous fistulae, large vessel occlusive disease, and dural sinus occlusion/thrombosis. MRA has not yet reached the point where it can replace conventional catheter angiography. This is most apparent when trying to evaluate 1) larger vessels which are typically difficult to visualize due to higher order motion terms (eg, carotid siphon); 2) the smaller cortical branches with relatively slow flow that would be necessary to see in patients with suspected vasculitis; and 3) any situation in which dynamic information is important such as with mass lesions or vascular malformations. These limitations must be taken into account when deciding on the appropriate imaging study for an individual patient. Large-scale, well-controlled prospective clinical trials will ultimately determine the role intracranial MRA will play in the evaluation of patients with suspected cerebrovascular disease.

Brain↗
PubMed1991

Magnetic resonance angiography of the carotid bifurcation.

MRA methods may be categorized into TOF or PC techniques. TOF techniques utilize flow related enhancement to provide high signal intensity blood. Two common TOF methods to visualize the bifurcations are sequential 2D or 3D imaging. In 2D imaging, the carotid bifurcation is visualized by obtaining a series of thin 2D axial gradient echo images. This stack of images may then be subjected to postprocessing to show just the vessel geometry, with the background stationary tissue suppressed. Advantages of 3D techniques include a reduction of T2* effects and a theoretical increase in signal to noise. While the scan time is increased with 3D imaging with the additional direction of phase encoding, overall imaging times are comparable for 3D and sequential 2D techniques, with both being shorter than the 3D PC technique. Advantages of PC angiography include direct and effective suppression of background tissues and definition of slow flow states. This method also has the potential for quantitative flow measurements. Because the signal of blood from this technique depends on flow induced phase change, signal loss from more complex flow is more problematic than with TOF methods. It is apparent from the plethora of methods available that no single MRA technique can answer all clinical questions and situations. Specific techniques and parameters will have to be tailored to individual patient needs. While this makes the routine application of MRA more complex, it also will ensure that the maximum diagnostic yield is achieved.

Carotid Arteries↗
PubMed1991

Magnetic resonance angiography of the intracranial vasculature.

Preliminary experience has shown that MRA can provide useful clinical information that complements the more traditional SE brain evaluation of patients with cerebrovascular disease. MRA is particularly appealing in that it provides a relatively rapid, noninvasive alternative to the existing vascular imaging modalities and the capability to evaluate the brain parenchyma directly. This can often be done without repositioning the patient or significantly prolonging the examination time. MRA sequences have been applied in the evaluation of patients with intracranial aneurysms, vascular malformations, vasoocclusive disease, neoplasms, and dural sinus thrombosis. The MRA study design and acquisition parameters are crucial and need to be optimized to maximize sensitivity and specificity of the examination based on the individual clinical presentation. The results of the SE and MRA studies should be evaluated together to obtain a definitive diagnosis or to determine whether conventional angiography is needed. As with any other diagnostic procedure, it is important to recognize the strengths and limitations of these techniques. Despite its advantages, MRA will not replace conventional catheter angiography in the near future. Rather, it will complement existing indications for conventional MR studies. Spatial resolution and intravascular signal loss due to rapid, complex flow continue to be the most limiting factors in intracranial MRA imaging. Significant improvements in these areas are currently being realized.

Brain↗
PubMed1990

Diagnosis of cerebrovascular disease in sickle cell anemia by magnetic resonance angiography.

The study of blood flow by means of magnetic resonance techniques has led to a noninvasive magnetic resonance angiography (MRA) technique for imaging large cerebral vessels. Ten children with sickle cell hemoglobinopathy and a history of acute neurologic syndromes were studied with combined parenchymal magnetic resonance imaging (MRI) and MRA. Six had abnormal MRI findings and MRA-defined luminal lesions in the vascular distribution of these parenchymal infarctions. The three children with previous intraarterial angiography had MRA abnormalities that corresponded with vascular lesions on conventional angiograms. Four had normal MRI and MRA findings. We conclude that a combination of MRI and MRA provides a noninvasive screening test for large-vessel disease in this population.

Anemia, Sickle Cell↗