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Biomedical subjects

F R Murtagh

Publications and source records attributed to F R Murtagh.

At least 19 recordsLinked to original sources
PubMed2006

Two cases of progressive multifocal leukoencephalopathy after allogeneic hematopoietic cell transplantation and a review of the literature.

Progressive multifocal leukoencephalopathy (PML) is a rare subacute demyelinating disorder of the central nervous system (CNS) caused by the DNA JC human polyomavirus. In immunocompromised hosts, PML is caused by reactivation of a latent infection rather than de novo primary exposure. PML in the setting of hematopoietic cell transplantation (HCT) is exceedingly rare. PML should be considered in the differential diagnosis of HCT recipients, autologous or allogeneic, presenting with worsening of neurological symptoms, especially associated with post-transplant neurodegenerative findings. Although DNA polymerase chain reaction (PCR) of the cerebrospinal fluid (CSF) has emerged as a promising tool for detecting JC virus, a negative result does not rule out PML. Brain biopsy remains the most reliable and accurate method for diagnosing JC virus-associated PML. Presently, there is no universally effective antiviral therapy against JC virus and outcome is fatal in the majority of cases. We hereby describe two cases of PML developing after allogeneic HCT and provide a comprehensive review of the literature.

Adult↗
PubMed2006

Proliferating trichilemmal cysts of the scalp on CT.

Proliferating trichilemmal cysts, also known as pilar tumors, are slow-growing lobulated masses most commonly found on the scalp of elderly women. We present the case of a 69-year-old woman with a 25-year history of multiple enlarging scalp masses. The patient was evaluated for surgical consultation after the dominant mass presented with malignant degeneration. A CT of the head revealed multiple large, subcutaneous, cystic masses with calcifications.

Aged↗
PubMed2003

MRI findings in Susac's syndrome.

BACKGROUND: Susac syndrome (SS) is a self-limited syndrome, presumably autoimmune, consisting of a clinical triad of encephalopathy, branch retinal artery occlusions, and hearing loss. All three elements of the triad may not be present or recognized, and MR imaging is often necessary to establish the diagnosis. OBJECTIVE: To determine the spectrum of abnormalities on MRI in SS. METHODS: The authors reviewed the MR images of 27 previously unreported patients with the clinical SS triad, and 51 patients from published articles in which the MR images were depicted or reported. RESULTS: All 27 patients had multifocal supratentorial white matter lesions including the corpus callosum. The deep gray nuclei (basal ganglia and thalamus) were involved in 19 (70%). Nineteen (70%) also had parenchymal enhancement and 9 (33%) had leptomeningeal enhancement. Of the 51 cases from the literature, at least 32 had callosal lesions. The authors could not determine the presence of callosal lesions in 18 of these patients, and only one was reported to have a normal MRI at the onset of encephalopathy. CONCLUSIONS: The MR scans in SS show a rather distinctive pattern of supratentorial white matter lesions that always involve the corpus callosum. There is often deep gray matter, posterior fossa involvement, and frequent parenchymal with occasional leptomeningeal enhancement. The central callosal lesions differ from those in demyelinating disease, and should support the diagnosis of SS in patients with at least two of the three features of the clinical triad.

Adult↗
PubMed2001

MRI of the brain is safe in patients implanted with the vagus nerve stimulator.

Metallic devices generally represent a contra-indication for MRI scanning. Based on laboratory testing, the neuro cybernetic prosthesis (NCP) is labelled MRI compatible when used with a send and receive head coil. However, there are no published clinical data to support the safety of brain MRI in patients with the NCP. Our objective was to report clinical experience with such a population. We questioned 40 centres that had implanted the NCP system as of 10/1/99. If MRI had been performed on any vagus nerve stimulator patients, we collected information on these patients, the MRI technique used, any events noted during the scan, including both subjective reports (by the patient ), and observable (objective) changes noted by the staff. Twelve centres (30%) responded. Over a time period of 3 years, there were a total of 27 MRI scans performed in 25 patients. All scanners were 1.5 T. A head coil was used in 26 scans, and a body coil in one. The indications for the scans were diverse. Seven were related to the epilepsy, including aetiology or pre-surgical evaluation. Others were unrelated, including brain tumours, cerebral haematoma, vasculitis, headaches, and head trauma. Three scans were performed with the stimulator on, while 24 were performed with the stimulator off. One patient had a mild objective voice change for several minutes. No other objective changes were noted in any of the patients. One 11-year old reported chest pain while experiencing severe claustrophobia. Twenty-five patients denied any discomfort around the lead or the generator. We conclude that this clinical series supports the safety of routine brain MRI using a send and receive head coil in patients implanted with the NCP System.

Adolescent↗
PubMed2001

Pathognomonic MR imaging findings in Balo concentric sclerosis.

Irregular, concentric zones of increased signal on T2-weighted cranial MR imaging studies may strongly suggest Balo concentric sclerosis (BCS), a rare but recognized variant of multiple sclerosis. Differentiating BCS from multiple sclerosis or neoplasm can be difficult clinically, but MR imaging findings noted in this case may be pathognomonic.

Adult↗
PubMed2000

Relationship of Schmorl's nodes to vertebral body endplate fractures and acute endplate disk extrusions.

BACKGROUND AND PURPOSE: Literature regarding clinical pain syndromes associated with acute, traumatic Schmorl's nodes (SNs) is limited. Our purpose was to determine whether an SN could be related to a previous traumatic event producing either acute SN or a vertebral endplate fracture. METHODS: Two neuroradiologists independently reviewed initial and follow-up MR examinations of 14 patients with a clinical diagnosis of acute, symptomatic thoracolumbar SNs or vertebral body endplate fractures that evolved into SNs to evaluate marrow edema, signal intensity, margin definition, presence of intravertebral extruded disk material, and pattern of contrast enhancement. RESULTS: Edema of the affected vertebral body, adjacent to an endplate without wedging or collapse, was observed on the initial MR images in all cases. The initial MR images of six (43%) of 14 patients exhibited only edema of the marrow immediately adjacent to the endplate without wedging or collapse. The MR images obtained at the time of follow-up showed subsequent formation of a chronic and eventually asymptomatic SN for all six patients. The initial MR images of eight (57%) of the 14 patients showed the typical appearance of acute SNs with marrow edema of the affected vertebra. The contrast-enhanced images of three patients manifested enhancement of the invaginated disk material in three (100%) of three cases and enhancement of the surrounding vertebral body in one case (33%). Six (43%) of 14 patients had acute typical compression fracture of a vertebral body of at least one additional level. CONCLUSION: Most (57%) of the SNs in this series could be traced to episodes of significant, sudden-onset, localized, nonradiating back pain and tenderness for which the MR images showed SNs surrounded by vertebral body marrow edema. The remaining SNs (43%) were not immediately apparent as SNs and manifested only as vertebral body edema representing endplate fracture but did evolve into classical chronic SNs that follow-up imaging revealed.

Acute Disease↗
PubMed1998

Automatic tumor segmentation using knowledge-based techniques.

A system that automatically segments and labels glioblastoma-multiforme tumors in magnetic resonance images (MRI's) of the human brain is presented. The MRI's consist of T1-weighted, proton density, and T2-weighted feature images and are processed by a system which integrates knowledge-based (KB) techniques with multispectral analysis. Initial segmentation is performed by an unsupervised clustering algorithm. The segmented image, along with cluster centers for each class are provided to a rule-based expert system which extracts the intracranial region. Multispectral histogram analysis separates suspected tumor from the rest of the intracranial region, with region analysis used in performing the final tumor labeling. This system has been trained on three volume data sets and tested on thirteen unseen volume data sets acquired from a single MRI system. The KB tumor segmentation was compared with supervised, radiologist-labeled "ground truth" tumor volumes and supervised k-nearest neighbors tumor segmentations. The results of this system generally correspond well to ground truth, both on a per slice basis and more importantly in tracking total tumor volume during treatment over time.

Algorithms↗
PubMed1997

Measurement of the normal optic chiasm on coronal MR images.

PURPOSE: To develop an objective method for measuring the optic chiasm and to document its normal range in size. METHODS: Measurements of the height and area of the optic chiasm, made on coronal T1-weighted MR images with the use of commercially available region-of-interest software, were obtained in 114 healthy subjects who had a total of 123 MR studies. A normal range and standard deviation were calculated, and the information was broken down by age and sex. RESULTS: The mean area of the optic chiasm was 43.7 mm2, with a standard deviation of 5.21. The mean width was 14.0 mm, with a standard deviation of 1.68. CONCLUSION: The area and width of the optic chiasm can be measured with the use of commercially available software, which allows an objective estimate of the chiasm's size. Knowledge of the normal size range of the optic chiasm can be helpful in the early detection of some disorders.

Adolescent↗
PubMed1996

MRI of spinal cord radiation necrosis simulating recurrent cervical cord astrocytoma and syringomyelia.

BACKGROUND: Although primary intramedullary tumors of the spinal cord with syrinx formation are well documented, there have been no reports of extensive syrinx formation or cystic degeneration associated with radiation necrosis. METHODS: We report a case of radiation necrosis and syrinx formation in a 49-year-old woman with a 5-year history of astrocytoma grade II of the cervical cord, who progressed to quadriparesis following surgery and radiation therapy. Magnetic resonance imaging (MRI) of the cervical and thoracic spine demonstrated enlargement of upper cervical cord (C1-C6) with diffuse increased signal enhancing mass by gadolinium, as well as appearance of syrinx from T4-T10. RESULTS: Autopsy findings indeed revealed a small, residual, infiltrating glioma in the upper cervical areas, but the diffuse parenchymal abnormality seen on MRI as prolonged T2 characteristics on double-echo spin-echo sequence was revealed to be radiation necrosis. CONCLUSION: What appeared to be a cystic cavity or syrinx at the thoracic level was also diagnosed as radiation necrosis with cyst formation on histologic examination.

Adult↗
PubMed1996

Magnetic resonance imaging of syrinx associated with intramedullary metastases and leptomeningeal disease.

Intramedullary spinal cord metastasis with an associated syrinx diagnosed by magnetic resonance imaging (MR) is described. The patient had documented simultaneous leptomeningeal spread of malignant cells and intramedullary spinal cord metastasis with hyalinized blood vessels, venous dilatation, and cavitation detected by autopsy. Metastasis to the spinal cord is unusual, but well described. Syrinx associated with intramedullary spinal cord metastasis has been detected rarely. MRI of syrinx and intramedullary spinal cord metastasis, and the possible pathogenesis of these lesions are discussed.

Adenocarcinoma↗
PubMed1994

Prevalence and percutaneous drainage of cysts of the sacral nerve root sheath (Tarlov cysts).

PURPOSE: To describe a percutaneous CT-guided method for drainage of perineurial (Tarlov) cysts, which are a cause of sciatica and low back pain, and to report the prevalence of these cysts within the population as detected by MR. METHODS: Five hundred sequential lumbosacral spine MRs were evaluated for the presence of a perineurial cyst. Using CT-guided percutaneous drainage techniques, seven cysts were drained in five symptomatic patients. RESULTS: Of the 500 sequential lumbosacral spine MRs, examinations from 23 patients showed perineurial cysts, a prevalence of 4.6%. Five patients (1%) were symptomatic from the cysts. After CT-guided percutaneous drainage, instant pain relief lasted from 3 weeks to 6 months without the risk or cost of spine surgery. CONCLUSIONS: Lumbosacral perineurial cysts are common lesions that are usually asymptomatic but may cause pressure symptoms. Cyst puncture can alleviate the pain. Although the cysts repressurized and the patients' symptoms returned in most cases, this technique seems to be a quick and simple way of at least attaining a pain-free interval and possibly a complete cure as occurred in one patient in this study.

Adolescent↗