Biomedical subjects

W M Kelly

Publications and source records attributed to W M Kelly.

At least 19 recordsLinked to original sources

PubMed1999

Post-therapy serum prostate-specific antigen level and survival in patients with androgen-independent prostate cancer.

BACKGROUND: With an hypothesis that post-chemotherapy changes in serum prostate-specific antigen (PSA) levels might serve as a surrogate marker for assessing prostate cancer outcome (i.e., survival), we studied the relationship between pretherapy and post-therapy prognostic factors and survival in patients with androgen-independent prostate cancer. METHODS: A prognostic model for survival based on pretherapy and post-therapy parameters was developed from the clinical data on 254 patients with androgen-independent prostate cancer treated with 11 different protocol therapies at Memorial Sloan-Kettering Cancer Center. The model was validated by use of an independent dataset of 541 patients enrolled in two randomized phase III trials. RESULTS: In multivariate analysis, a post-therapy decline in PSA levels of 50% achieved in 12 weeks was a statistically significant factor associated with survival (two-sided P = .0012). A similar outcome was obtained with the use of an 8-week time frame. Elevated pretherapy level of serum lactate dehydrogenase (two-sided P = .0001), lower pretherapy level of hemoglobin (P = .0001), and younger age (two-sided P = .0430) had a statistically significant negative impact on outcome. Median survival times were 23, 17, and 9 months for low-, intermediate-, and high-risk groups of patients defined by the prognostic model, respectively. CONCLUSION: This study confirms the prognostic value of a post-therapy decline in PSA of 50% or greater from baseline in relation to survival in patients with androgen-independent prostate cancer treated with a variety of therapies. Two consecutive determinations at 4-week intervals can be used as an end point for efficacy in phase II trials of therapies in this disease.

Aged↗

PubMed1993

Isolated abducens nerve palsy: MR imaging findings.

The abducens nerve, the sixth cranial nerve, innervates the lateral rectus muscle of the eye and is responsible for lateral horizontal ocular movement. A wide variety of abnormalities, both primary to the nerve itself and secondarily involving the nerve, can paralyze the abducens nerve. MR imaging offers the best opportunity to detect the underlying abnormality causing abducens nerve palsy. In this pictorial essay, we illustrate the MR imaging features of numerous conditions that cause isolated abducens nerve palsy.

Abducens Nerve↗

PubMed1993

Idiopathic hypertrophic cranial pachymeningitis. Report of three cases.

Hypertrophic cranial pachymeningitis is a rare, idiopathic form of granulomatous pachymeningitis. This report describes three cases of hypertrophic cranial pachymeningitis and discusses the clinical, radiographic, and pathological findings in these and other reported cases. These lesions typically cause progressive cranial nerve palsies, headaches, and cerebellar dysfunction. They occur in patients of all age groups; the peak incidence is in the sixth decade. Hypertrophic cranial pachymeningitis is best identified by magnetic resonance imaging. The diagnosis is established by excluding all other granulomatous and infectious diseases. A dural biopsy is essential to confirm the diagnosis. Hypertrophic cranial pachymeningitis is initially responsive to steroid therapy, but in most cases it recurs or progresses despite treatment. Surgical excision of granulomas is occasionally necessary to alleviate a mass effect. The long-term outcome remains uncertain for most patients, but progressive disease is usually fatal owing to cranial neuropathies.

Aged↗

PubMed1993

Radiographic assessment of discogenic disease of the spine.

Magnetic resonance imaging has gained favor as the imaging modality of choice for evaluation of disc disease that affects the lumbar and thoracic spinal segments. This new noninvasive modality also competes favorably with myelography and CT for evaluation of cervical spine disc disease. An algorithmic approach to use of various imaging modalities for evaluation of suspected disc disease is provided in Figure 15. Important advantages of MR imaging relate to its multiplanar capability and unprecedented soft-tissue contrast for simultaneous evaluation of the thecal sac and spinal canal contents. These advantages often translate to more accurate and specific diagnoses related to degenerative disc disease.

Cervical Vertebrae↗

PubMed1991

Neuropsychological, neurological, and MRI correlates of dementia in advanced Huntington's disease: a single case study.

Affected Huntington's disease patients present with a progressive dementia that can be detected with a variety of neuropsychological procedures. Neuropsychological findings include impaired mental flexibility and concentration, deterioration of verbal and procedural memory, diminished nonverbal memory, and slowing of both fine and gross motor functions. Magnetic resonance imaging (MRI) offers unique advantages in depicting morphologic changes associated with Huntington's disease. Frontotemporal atrophy and, in particular, atrophy of the corpus striatum are characteristically observed. Given the ease of obtaining coronal images and the improved differentiation of gray matter and white matter, MRI can provide better identification of these findings than traditional imaging methods such as computed tomography (CT). Finally, the presence of steadily progressive neuropsychological deterioration in conjunction with characteristic atrophy observed on MRI can be combined with diminished metabolic activity of the corpus striatum as observed on positron emission tomography (PET) for added diagnostic specificity.

Dementia↗

PubMed1990

Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance.

Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel's patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift.

Blood Flow Velocity↗

PubMed1988

Common artifacts encountered in magnetic resonance imaging.

Magnetic resonance imaging has rapidly become a widely accepted and clinically useful imaging modality primarily because of its excellent contrast resolution, ability to perform multiplanar acquisition, and the lack of ionizing radiation. However, the nuances of image acquisition are not trivial. Many technical factors must be considered and understood in order to knowledgeably choose sequence parameters that suppress artifacts and optimize the diagnostic quality of a particular MR examination. Even then, residual artifacts may persist. The presence of the artifacts and their technical basis must be understood before completely accurate MR interpretation can be rendered.

Brain↗

PubMed1987

Rathke cleft cysts: CT, MR imaging, and pathologic features.

The authors retrospectively reviewed the clinical, computed tomography (CT), and magnetic resonance (MR) imaging findings in seven patients with pathologically proved Rathke cleft cysts. All the cysts were located in the anterior sella turcica or the anterior suprasellar cistern. Five cysts had both intra- and suprasellar components, one was entirely intrasellar, and the other was predominantly suprasellar in location. The size of the cysts ranged from 8 to 20 mm. CT scans demonstrated low-density homogeneous lesions in four cases. On MR images of three of these four cases, the cysts had the same intensity as cerebrospinal fluid on T1- and T2-weighted images, while in the fourth case, the cyst was hyperintense on the T1-weighted images. In the remaining three cases, CT showed slight hyperdensity relative to brain parenchyma, suggestive of contrast enhancement. MR showed signal heterogeneity of these lesions with focal components of diminished signal intensity of T2-weighted images. These same foci appeared iso- to slightly hyperintense on T1-weighted images.

Adult↗

PubMed1987

MR imaging of paragangliomas.

MR imaging of 15 paragangliomas in 10 patients was compared with CT of 13 of the lesions in eight patients. All lesions were confirmed with angiography. All lesions were detected by MR and CT with the exception of one small glomus tympanicum tumor that was seen only in retrospect with MR. CT better demonstrated subtle osseous changes of the skull base and the relation of the tumor to the middle ear structures. MR better demonstrated the relation of the tumor to the adjacent internal jugular vein and carotid artery. The paragangliomas had a characteristic MR appearance based on their vascularity. Serpiginous areas of signal void representing high vascular flow were interspersed among areas of high signal intensity caused by slowly flowing blood and tumor cells. This "salt-and-pepper" pattern was seen in all lesions greater than 2 cm in maximal dimension. MR was therefore able to accurately characterize the tumors as highly vascular. Multiplanar imaging and good tissue contrast and anatomic detail permitted display of the relations of these neoplasms to surrounding carotid sheath vessels and to intracranial structures better than did CT. In this experience, the MR appearance of paragangliomas was quite characteristic and differed markedly from meningiomas, neuromas, and metastatic disease of the skull base.

Carotid Body Tumor↗

PubMed1986

Pituitary adenomas: high-resolution MR imaging at 1.5 T.

The magnetic resonance (MR) images of 28 patients with surgically confirmed pituitary adenomas were retrospectively evaluated. The examinations were performed on a 1.5-T superconducting MR system using a multisection spin-echo technique with 3-mm-thick sections and a 256 X 256 matrix. T1- and T2-weighted images were obtained in sagittal and coronal planes. The MR findings were correlated with detailed operative reports and diagrams. There were 11 microadenomas and 17 macroadenomas. Ten of the microadenomas and all of the macroadenomas were accurately localized and their extent delineated, particularly on T1-weighted coronal sections. Adenomas typically appeared hypointense on T1-weighted coronal sections. The appearance on T2-weighted images was variable, and generally the lesions were less well seen. Involvement of parasellar structures, particularly the optic chiasm and cavernous sinuses, was accurately depicted. Cyst formation and hemorrhage could be characterized in some instances. In general, there was excellent correlation between MR imaging and operative findings.

Adenoma↗

PubMed1986

Intracranial lesions: flow-related enhancement on MR images using time-of-flight effects.

Many physico-anatomic variables and instrument parameters influence the relative magnetic resonance signal intensity of vascular channels. The interaction of these mechanisms is complex, but their composite effects can be accounted for by two main categories of flow phenomena: time-of-flight effects and spin-phase changes. Of these two mechanisms only the time-of-flight effect known as flow-related enhancement produces augmentation of intravascular signal. Flow-related enhancement can potentially provide positive contrast of diagnostic value in terms of anatomic depiction of vascular detail as well as physiologic characterization of blood flow. The authors have used a single-section, selectively irradiated, spin-echo pulse sequence to maximize flow-related enhancement within a variety of intracranial lesions, as a supplement to their regular imaging. The technique was found to be diagnostically useful in improving the conspicuity of vascular lesions, in determining vessel patency, in distinguishing flow void from calcification, and in obtaining semiquantitative information about flow dynamics.

Brain Diseases↗

PubMed1985

Intra-arterial DSA: early experience with a 1024(2) matrix.

Twenty patients were studied with intra-arterial digital subtraction angiography (IA DSA), utilizing a 1024(2) matrix memory. Acquisition of the images was through a prototype television camera incorporating a finely focused electron beam. In five cases, comparison between a 512 X 512 (512(2)) matrix acquisition and a 1024 X 1024 (1024(2)) matrix acquisition mode was made, with injections occurring in the same vessel in the same patient. The clinical material demonstrated no significant improvement in image quality at the 4 1/2 as well as the 6 inch image intensifier (II) modes. However, the 1024(2) matrix combined with the 9 inch II mode showed foci of disease and normal anatomy with detail not always seen on the 9 inch II when a 512(2) matrix was used. In no case, however, was the basic diagnosis missed with the 512(2) matrix. Spatial resolution, as measured from lead bar test pattern images, demonstrated that the 1024(2) matrix allows a 70% or greater improvement in spatial resolution over the 512(2) for the 4 1/2, 6 and 9 inch II modes. For a given mode the radiation dose was held constant for the two matrix sizes.

Adult↗

PubMed1985

Magnetic resonance scanning in orbital tumor diagnosis.

We have compared the accuracy of magnetic resonance scanning (MRI) versus computed tomography (CT) in the differentiation of lateral orbital masses. The MRI results did not improve our ability to accurately diagnose malignant epithelial and lymphoid tumors.

Adolescent↗

PubMed1985

Central nervous system tumors in children: detection by magnetic resonance imaging.

Fifty-one pediatric patients who were suspected of having central nervous system (CNS) tumors underwent magnetic resonance (MR) imaging using a 0.35 T Diasonics MT/S system. Pulse intervals (TR) ranged from 0.5 to 2.0 seconds with echo delays (TE) of 28 and 56 msec. The ability of MR and contrast-enhanced CT to detect focal lesions, determine lesion extent, and evaluate associated abnormalities was compared. In most patients in whom there was suspected spinal cord disease, comparison with myelography was made. Thirty-three intracranial lesions were detected with at least one imaging modality in 43 cranial examinations. MR was judged superior to CT in 14 of these cases and CT superior to MR in only one. Of eight spinal examinations, there were six that demonstrated abnormal findings. MR was superior to CT in all six cases and better than myelography in four of five cases where myelography was performed. Spin echo (SE) sequences with long pulse intervals were the most sensitive, but in some cases short pulse intervals permitted further characterization of the lesion. Patient motion was not a problem; sedation was routinely used in children younger than five years of age. MR imaging has rapidly become a valuable diagnostic modality in neuroradiology. The lack of ionizing radiation and the ability to evaluate the spinal cord noninvasively makes it particularly attractive in examination of children.

Adolescent↗

PubMed1985

Cystic intracranial lesions: magnetic resonance imaging.

Thirty-three patients with cystic intracranial lesions were examined with both magnetic resonance (MR) imaging and CT scanning. The abnormalities imaged included 11 arachnoid cysts, 10 cystic tumors, six postoperative cysts, and three colloid cysts. The intensity patterns of the cyst contents as encoded with routine spin-echo imaging sequences enabled subdivision of the cysts into three categories. Arachnoid and postoperative cysts had an intensity pattern identical to cerebrospinal fluid. More proteinaceous cysts, including inflammatory cysts and nonhemorrhagic tumoral cysts, had an intermediate intensity pattern with characteristically low intensity on the short TR sequence (0.5 sec), but had clearly higher intensity than cerebrospinal fluid on the long TR sequences (2 sec). Finally, three cystic tumors with hemorrhagic fluid and three colloid cysts had a distinctly different pattern of high intensity on all four MR sequences through the same section. MR was superior to CT in characterizing intracranial cystic lesions because of its ability to categorize cysts into these three groups on the basis of the intensity pattern of cyst contents, thereby improving diagnostic specificity and patient management.

Adolescent↗

PubMed1985

Reproducibility of relaxation times and spin density calculated from routine MR imaging sequences: clinical study of the CNS.

This study was undertaken to determine if routine clinical magnetic resonance imaging sequences using only two different repetition times (TRs) and with only two sequential spin echoes (SEs) can be used to calculate reproducible relaxation time and spin density values for normal central nervous system tissue using a 0.35 T production-model instrument. In 43 patients 650 regions of interest of 11 different anatomic sites were measured. T1 and T2 relaxation times and spin density were measured. For each anatomic location, the mean and standard deviation of these values were determined. In most solid regions of brain, the standard deviation of both T1 and T2 was 4%-8%. Relaxation times of cortical gray matter varied more, with a standard deviation of 10%, probably because of volume-averaging with adjacent cerebrospinal fluid (CSF). CSF and ocular vitreous humor were neither reproducibly nor accurately measured because of the short TR and TE settings of the imaging sequences relative to the long T1 and T2 relaxation times of these substances. Significant and reproducible differences were found between the spin densities of gray matter and white matter, as well as between different regions of white matter. These differences are of major importance in contrast discrimination of gray and white matter on the long TR images. Knowing that relaxation values and spin densities calculated from routine imaging sequences are in fact reproducible, these normal ranges can now be used to investigate changes occurring in disease states.

Adolescent↗

PubMed1984

Epidural block: myelographic evaluation with a single-puncture technique using metrizamide.

A simplified technique using metrizamide for myelographic delineation of extrinsic spinal cord blocks is described. This method was successfully used in eight consecutive examinations without adverse effects. A single lumbar puncture is followed by instillation of metrizamide into the subarachnoid space. With the needle left in place and the patient in the Trendelenburg position, the contrast agent is sequentially displaced above any encountered extradural blocks by further injection of diluent or sterile saline into the caudal thecal sac. Thus, multiple levels of blockage may be defined at their upper and lower margins. This method offers an expedient and safe alternative to combined lumbar and C1-2 lateral cervical puncture, leaves a minimum amount of metrizamide "trapped" below a block, and has several advantages over use of iophendylate. Additionally, the examination may be supplemented with CT scanning when desirable.

Adult↗

PubMed1984

Magnetic resonance of the brain: the optimal screening technique.

Seventy consecutive patients were examined with magnetic resonance (MR) and computed tomography (CT) of the brain. Each study was independently reviewed. Focal abnormalities were detected by one or both modalities in 51 patients. Neoplastic, infectious, vascular, demyelinating, metabolic, and congenital disorders of the brain were included. The MR pulse sequence that best detected these abnormalities was a spin-echo multisection technique that used a long interval between RF excitations (TR = 1500 or 2000 msec). Forty-eight of 51 patients showed focal lesions with this technique. A supplementary MR pulse sequence with a short TR (500 msec) was useful in helping to characterize certain lesions with a long T1 relaxation component, but in 10 of 26 positive cases in which this sequence was added it would have missed the abnormality had it been the sole sequence used. MR missed focal lesions in 3 of 51 patients. These were lesions that required thin-section (1.5 mm) CT techniques. Two were intrasellar, and one was an intracanalicular neurinoma. In 17 of 48 patients, CT missed the focal lesion seen with MR. Based on this experience, it is concluded that the long TR multisection spin-echo sequence is the optimal MR screening technique for detection of most brain abnormalities, and is more sensitive than CT. Currently, CT remains the screening modality of choice when high-resolution, thin-section studies in the pituitary, inner ear, and orbital regions are indicated.

Brain Diseases↗