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Biomedical subjects

G S Forbes

Publications and source records attributed to G S Forbes.

45 records · Page 3Linked to original sources
PubMed1980

Radiology of cerebrospinal fluid rhinorrhea.

Fifty-one patients with cerebrospinal fluid rhinorrhea were evaluated at the Mayo Clinic from 1974 to 1977. The causes of the leak were fairly even distributed among postoperative, traumatic unrelated to previous surgery, and nontraumatic. The slightly fewer patients with a traumatic cause compared with those reported in most series reflects the referral patterns and surgical nature of the practice at the institution. Three-fourths of the patients had plain films of the skull, although the site of the leak was identified in only 21% of them. Two-thirds of the patients had tomography, which was helpful in 53%, especially in 10 of the 13 patients with traumatic nonpostoperative cerebrospinal fluid rhinorrhea. Posteroanterior tomography generally was more helpful than lateral tomography, except in leaks around the frontal sinuses. Radioisotope cisternography with intranasal pledgets helped localize the site of leak in 50% of patients and suggested the site of the leak in 25%. Radioisotope cisternography with pledgets often gave helpful positive results when the plain films and tomography were not helpful.

Adolescent↗
PubMed1978

Computed tomography in the evaluation of subdural hematomas.

Computed tomographic (CT) scans used in the diagnosis and management of subdural hematomas were analyzed with respect to their contribution to angiography and surgery. There has been a progressive increase in the use of CT in evaluating post-traumatic and postoperative subdural hematomas at the Mayo Clinic. At present, 40% of all patients undergo operation on the basis of the CT findings alone. False-positive diagnoses revealed at surgery have decreased to less than 4%. Erroneous negative interpretations have involved 10% of all patients whose diagnosis was subdural hematoma. Criteria for the interpretation of scans have been established.

Brain↗
PubMed1977

Radiographic manifestations of bone metastases from renal carcinoma.

From 1964 to 1974, 1,668 patients with renal carcinoma were seen at the Mayo Clinic. Bone metastases were present in 167 of these patients (only lung metastatic involvement ranked higher in frequency). More than one-third of the patients with bone metastasis from renal carcinoma had this as a presenting lesion of occult renal tumor. This group constituted 4% of all patients with renal carcinoma evaluated during the study period. While most bone lesions were in the pelvis and lower lumbar spine, any bone may be involved. All patients with bone metastases from renal carcinoma have a poor prognosis. However, some bone lesions appeared as long as 10 or more years after the initial tumor. The most common radiographic features are a lytic destructive process with indistinct margins, erosion of the cortex, and frequent expansion into the soft tissues. Pathological features are common in the long bones, and calcifications are occasionally seen. The synovial joints are not affected. A well defined sclerotic margin is a common finding after radiation treatment, although it is not a reliable indicator of the stability of the lesion.

Adult↗
PubMed1976

Genitourinary involvement in chronic granulomatous disease of childhood.

A second case of symptomatic renal involvement of chronic granulomatous disease of childhood is reported, and all previous cases of documented genitourinary lesions in this disease are reviewed. Although frequent infections of other organ systems are a well recognized part of chronic granulomatous disease, involvement of the urinary tract has been rarely reported. The nature of the few cases described suggests that extensive insidious destruction occurs before urinary tract involvement is clinically suspected.

Adolescent↗
PubMedDate not supplied

Field strength in neuro-MR imaging: a comparison of 0.5 T and 1.5 T.

A study was undertaken comparing neurological magnetic resonance imaging at high (1.5 T) and mid (0.5 T) field strengths. Twenty-eight patients (20 head and 8 spine) from our routine case load volunteered to undergo two consecutive and identical MR studies on the two systems. The two MR systems were built by the same manufacturer and were equipped with essentially identical hardware and software. Individual patient studies were performed consecutively in adjacent MR suites, and pulse sequence parameters were replicated exactly at the two field strengths. One exception to this rule was that the second echo of the long TR sequence in the head was acquired with a narrow receiver bandwidth on the 0.5 T system. The resulting axial double echo long repetition time (TR) and sagittal short TR head images and sagittal short and double echo long TR spine images were graded by two blinded observers (senior staff neuroradiologists) on two levels. First, the images were graded for image quality, i.e., conspicuousness of artifacts and clarity in depiction of normal and pathologic anatomy. Second, diagnostic accuracy of MR was assessed relative to the clinical-pathologic diagnosis in each case. The image quality of the 1.5 T system was rated superior in both the head and spine for most specific items assessed. This observer preference for 1.5 T images did not, however, translate into greater diagnostic accuracy for the 1.5 T system in the head. Although the 1.5 T system did have a slight advantage in diagnostic accuracy in the spine, a significant difference was not found.

Brain↗
PubMedDate not supplied

Embolization of spinal dural arteriovenous fistula with polyvinyl alcohol particles: experience in 14 patients.

PURPOSE: To assess the effectiveness, initial and long term, of embolization using polyvinyl alcohol particles (PVA) particles in patients with spinal dural arteriovenous fistulas (SDAVF). METHODS: The initial treatment in 14 patients with SDAVF was embolization with PVA particles. Postembolization occlusion of the SDAVF was documented angiographically in all cases. RESULTS: All 14 patients initially showed an improvement in clinical symptoms, but the neurologic status of 11 patients subsequently deteriorated. Of the 11 patients who had recurrence of symptoms, nine had angiographically proven recurrences of their SDAVF while two had negative follow-up of spinal angiography. PVA embolization is ineffective for the treatment of SDAVF and is not without risk. CONCLUSION: On the basis of a literature review of the other two alternative treatments (operation or liquid adhesive embolization) available for SDAVF and our preliminary experience with N-butyl cyanoacylate (NBCA) embolization, we suggest that NBCA embolization be the initial treatment of choice for SDAVF; if that procedure is not possible, or is unsuccessful, then operation is recommended.

Aged↗
PubMedDate not supplied

Radiologic evaluation of tumors of the optic nerve.

The case material of 42 patients with primary tumors of the optic nerve and chiasm examined at our institution within a 10 year period was reviewed. In each case, the radiologic data and certain clinical information were compiled to determine the role of radiology in the workup of patients with these tumors and to compare the results of various imaging methods. Although different types of information are obtained from each method, late-generation computed tomography provides the most useful and complete information about optic nerve gliomas and intraorbital optic nerve meningiomas. Angiography is also helpful in the evaluation of intracranial optic nerve meningiomas.

Adolescent↗
PubMedDate not supplied

Rathke cleft cyst: CT, MR, and pathology of 23 cases.

OBJECTIVE: We report the radiologic findings in 23 cases of Rathke cleft cyst (RCC) and correlate them with the histopathology. MATERIALS AND METHODS: We reviewed the radiology and pathology of 23 cases of surgically treated RCC operated upon at our institution or referred in consultation. RESULTS: There appears to be a correlation between the MR and CT appearance of the cyst, the gross appearance of the cyst contents, and the histopathologic characteristics of the cyst lining. Some of the lesions demonstrated peripheral enhancement, which in two cases was clearly due to a peripherally displaced rim of pituitary tissue. CONCLUSION: The appearance of RCC with CT and MRI is variable, and radiologic diagnosis can be difficult. Imaging features such as a sellar epicenter, smooth contour, absence of calcification, absence of internal enhancement, and homogeneous attenuation or signal intensity within the lesion suggest the diagnosis of RCC. Rim enhancement does not correlate with the presence of squamous metaplasia, hemosiderin, or cholesterol within the cyst wall and is not consistently seen in cases with changes of mild, chronic inflammation. In some cases, rim enhancement is due to a peripherally displaced rim of pituitary tissue.

Adolescent↗