Arteriovenous fistula simulating arteriovenous malformation.

A 36-year-old man was thought (for 20 years) to have an arteriovenous malformation that could not be excised. Repeated ligations of proximal arterial supply to the vascular lesion were only transiently beneficial and may have caused a delay in correct diagnosis because of impaired angioaccess. Once it was discovered that he had an arteriovenous fistula--probably caused by a tonsillectomy at age 6--it was possible to occlude the fistula with detachable balloons. The mass and his headaches subsequently resolved. AV fistulas are caused by trauma. Growth of AVMs is often stimulated by trauma. Both lesions have pulsatile masses associated with overlying bruits. The differential diagnosis can usually be made by arteriography, since AV fistulas are acquired lesions with a single communication between an artery and a vein, whereas AVMs are congenital lesions with multiple, large arterial feeding vessels and numerous arteriovenous communications. Proper diagnosis is important, since AVMs are aggressive lesions that tend to regrow if not completely excised. AV fistulas will be cured if the single arteriovenous communication can be obliterated. Proper treatment for AV fistula is obliteration of the single arteriovenous communication, operatively or with occlusive balloons; treatment of AVMs--when possible--is excision of the entire mass, combined (on occasion) with preoperative embolization of the tumor mass. This case report emphasizes the importance of accuracy in the differential diagnosis between arteriovenous malformations and arteriovenous fistulas; moreover, it demonstrates both the ineffectiveness and deleterious consequences of proximal arterial ligation, since collateral development is enhanced and angiographic access is compromised.

CT of cerebral abnormalities in precocious puberty.

True precocious puberty occurs as a result of the premature release of luteinizing hormone-releasing hormone from the hypothalamus, which stimulates the secretion of the pituitary gonadotropins, which in turn stimulate the gonadal sex steroids. The differential diagnosis of true precocious puberty includes cerebral and idiopathic categories. This differentiation, which cannot be made endocrinologically due to similarities in pituitary gonadotropin and sex steroid levels, may be facilitated by high-resolution CT. A CT study of 90 children (73 girls and 17 boys) with true precocious puberty was performed at the NIH to detect cerebral causes of their precocious puberty. Thirty-four cerebral abnormalities were demonstrated in 32 children, 16 boys and 16 girls. These included hypothalamic hamartomas (17), hypothalamic astrocytoma (one), optic chiasm lesions (six), ventricular abnormalities (eight), arachnoid cyst (one), and teratoma (one). The CT appearance of these cerebral abnormalities is discussed and related to the endocrinologic findings and natural history of true precocious puberty. A practical neuroradiologic approach to the evaluation of children with precocious puberty is presented.

Pituitary and ovarian abnormalities demonstrated by CT and ultrasound in children with features of the McCune-Albright syndrome.

In a random series of 97 children referred to the National Institutes of Health with a presumptive diagnosis of precocious puberty, eight girls were found to have features of the McCune-Albright syndrome, including fibrous dysplasia of bone and/or skin lesions resembling café au lait spots. Two girls had the classic triad. Radiographic evaluation of these patients included computed tomography of the head and pelvic ultrasound. The pituitary glands were suspicious for abnormality in five of the eight girls. Seven girls underwent pelvic ultrasound, and in all of them the ovaries were considered to be abnormal for their chronological age; in addition, two had functional ovarian cysts. The role of diagnostic radiological studies in the diagnosis of this syndrome is discussed.

Luteinizing hormone-releasing hormone analog treatment of boys with hypothalamic hamartoma and true precocious puberty.

A long-acting analog of LRH (LRHa) has been shown to suppress pituitary gonadotropin and estradiol secretion to prepubertal levels in girls with idiopathic true precocious puberty. We treated six boys, aged 1-6 yr, with true precocious puberty due to hypothalamic hamartoma for 6-24 months with daily sc injections of LRHa. The patients had enlarged testes (6-25 ml), Tanner stage II-IV pubic hair, facial and axillary hair, increased growth rate, and an advanced bone age. Frequent erections occurred in all patients. Computed tomography of the head showed abnormalities characteristic of hypothalamic hamartoma (0.5-3 cm in diameter) in each boy. Each patient had measurable LH and FSH levels, with pulsed nocturnal secretion, and pubertal LH and FSH responses to LRH. Serum testosterone was in the range for normal adult men (200-600 ng/dl). LRHa significantly decreased basal LH (P less than 0.005) and FSH levels (P less than 0.01), LRH-stimulated gonadotropin levels (P less than 0.005), and serum testosterone levels (P less than 0.005). Testis size decreased significantly (P less than 0.005). Annualized growth velocity (centimeters per yr) decreased significantly compared to the pretreatment growth rate (P less than 0.01). Bone age advancement per yr slowed significantly during the course of LRHa treatment (P less than 0.01). Pubic hair, facial hair, and erections decreased in all patients. LRHa is an effective treatment for boys with precocious puberty associated with hypothalamic hamartoma. Chronic therapy will be required, however, to assess the ultimate effect of LRHa.

Ultrasound evaluation of female isosexual precocious puberty.

Fifty-six female children with signs of precocious puberty were examined. Adult-sized ovaries and an intermediate-sized uterus were characteristic of true sexual precocity, either idiopathic or due to a CNS lesion. Premature thelarche and premature adrenarche showed normal infantile pelvic organs, while in cases of precocious pseudopuberty, the appearances of the ovaries and uterus varied depending upon the underlying process. Large ovarian cysts and large ovaries were found in six patients with McCune-Albright syndrome. An ultrasound study is of benefit in the evaluation of female children with precocious sexual development because it can demonstrate the adult-sized ovaries of true precocious puberty, thereby distinguishing this condition from premature thelarche and premature adrenarche, and it can demonstrate specific causes of precocious sexual development, such as adrenal and ovarian tumors and ovarian cysts.

Hyperprolactinemia, amenorrhea, and galactorrhea. A retrospective assessment of twenty-five cases.

The syndrome of hyperprolactinemia, galactorrhea, and amenorrhea is frequently caused by a pituitary tumor. Transsphenoidal surgical removal is often advocated for microadenomas, tumors smaller than 10 mm, to prevent the progression of these small adenomas into large tumors. Because no strong evidence indicates that microadenomas naturally progress to macroadenomas, we studied 25 women who had had hyperprolactinemia, amenorrhea, or galactorrhea for a mean duration of 11.3 years. Their mean initial prolactin level was 225 ng/mL (normal, less than 36 ng/mL). Of 22 patients presenting with amenorrhea, 7 resumed menses spontaneously. Galactorrhea resolved completely in 6 of the 19 patients with this disorder. Only 1 patient had progression of a sellar abnormality, and this was slight. Visual fields remained full in all patients, and basal adrenal and thyroid functions remained normal. The mean prolactin level was 155 ng/mL at the reevaluation (p less than 0.01, initial versus reevaluation levels). Hyperprolactinemia apparently has a benign clinical course in most women, and we advocate a conservative approach to management of this disorder.

Successful treatment of a group of spinal cord arteriovenous malformations by interruption of dural fistula.

As demonstrated by selective spinal cord arteriography, over 80% of spinal cord arteriovenous malformations (AVM's) occupy a predominantly extramedullary position. Current therapy frequently requires surgical stripping of the long dorsal intradural vessel(s) from the underlying spinal cord over many cord segments. The authors report six patients with a dural arteriovenous fistula fed by a cluster of abnormal epidural arteries. These vessels, which surrounded and were embedded into the dural covering of a thoracic nerve root, drained into a long sinuous intrathecal paramedullary vein(s). The angiographic and surgical appearance of the intradural component of these lesions was identical to that of lesions previously classified as Type I AVM's of the spinal cord. All patients had symptoms and signs of myelopathy. In five patients, surgery was limited to coagulation and excision of the extradural vessels and division of the intradural arterialized vein. Progressive improvement began within days following surgery. No residual abnormality was demonstrated by postoperative selective spinal cord arteriography, which was performed in all five patients. The findings support those of Kendall and Logue, that surgery restricted to elimination of the arteriovenous fistula at the intervertebral foramen is curative, and that more extensive surgery is unnecessary for this subgroup of AVM's of the spinal cord. These lesions comprise a sizable percent of all spinal AVM's. Resolution of myelopathy in these patients supports the hypothesis that venous hypertension causes chronic progressive myelopathy.

Calcified chronic spinal subdural hematoma demonstrated by computed tomography.

Spinal subdural hematoma is a rare clinical condition that may result in spinal cord compression. The authors present a patient with chronic calcified spinal subdural hematoma demonstrated by computerized tomography. Surgical removal resulted in clinical improvement.

CT of the pituitary gland in multiple endocrine neoplasia type 1 syndrome.

Multiple endocrine neoplasia type 1 (MEN-1) is an autosomal dominant disease involving tumors of the parathyroid, pancreas, and pituitary glands. Over 50% of the patients with this syndrome will have involvement of the pituitary gland. Computed tomography (CT) of the head was performed in 21 of 42 patients with the clinical diagnosis of MEN-1. CT demonstrated pituitary abnormalities in 15 patients, 13 of whom had pituitary endocrine dysfunction. The most common endocrinopathy was hyperprolactinemia, documented in nine patients. Hypopituitarism due to nonfunctional adenoma was found in two patients, and acromegaly and Cushing disease in individual cases. The appearance of the pituitary gland in CT evaluation of the sella in patients with MEN-1 is presented.

Size and erosive features of the sella turcica in acromegaly as predictors of therapeutic response to supervoltage irradiation.

Basal growth hormone levels and the sella turcica of patients with acromegaly were evaluated. Fifty of these patients were followed up, with fasting growth hormone levels determined at several intervals within 10 or more years after supervoltage pituitary irradiation. Prior to therapy, basal growth hormone levels were positively correlated with an estimate of tumor size, as reflected by sella abnormalities. Sella abnormality criteria, developed by Hardy et al., were used as the correlating factor. The percentage of fall in growth hormone levels after radiotherapy was indistinguishable in these patients, regardless of sella grade. However, since the larger, more erosive, tumors were associated with higher pre-therapy plasma growth hormone levels, the median growth hormone levels were higher at various intervals after treatment of this group. We suggest that the size and erosive features of the bony sella offer a crude, but possibly useful, predictor of response to supervoltage irradiation in acromegaly.

Digital subtraction angiography and dynamic computed tomography in the evaluation of arteriovenous malformations and hemangioblastomas of the spinal cord.

Digital subtraction angiography (DSA) and dynamic computed tomography (DCT) were used in the evaluation of five patients with surgically approachable vascular lesions of the spinal cord, including three arteriovenous malformations (AVM), one hemangioblastoma, and one lesion with a questionable radiographic-surgical diagnosis (AVM? hemangioblastoma?). Digital subtraction angiography was positive in three of the five cases and was particularly informative in the patient with hemangioblastoma, even vis a vis arteriography, which is considered the definitive diagnostic test for these lesions. Dynamic computed tomography was positive in four of the five cases. From this preliminary study, DSA and DCT appear to be useful screening and follow-up procedures which, in a number of aspects, complement each other.

Primary demyelinating disease simulating glioma of the corpus callosum: report of three cases.

Computerized tomography (CT) has made it easier to distinguish tumoral from nontumoral diseases of the central nervous system. In the presence of mass effect, however, this distinction may be difficult or impossible to make. Primary demyelinating disease may occasionally present as a focal cerebral mass. The authors report three cases of primary demyelinating disease of the brain involving the corpus callosum and periventricular white matter and associated with mass effect, which proved difficult to differentiate from infiltrating "butterfly" gliomas.

Experimental glioma in primates: a computed tomography model.

Owl and squirrel monkeys inoculated intracerebrally with human polyomavirus obtained from the brain of patient with progressive multifocal leukoencephalopathy developed cerebral gliomas. Among these tumors, three out of five were detected and accurately localized by contrast enhanced computed tomography (CT) when the animals were still clinically normal. Various CT features of these tumors corresponded to specific pathologic changes, such as histologic type and presence of hemorrhage and necrosis. Also, tumor progression was clearly demonstrated in repeat scans of one animal. The CT sensitivity and the capability of distinguishing various pathologic features are encouraging. It appears that a much needed, suitable model of experimental cerebral tumors in primates is now available for CT studies.

Serial measurements of CT attenuation and specific gravity in experimental cerebral edema.

Vasogenic cerebral edema was induced cryogenically in rhesus monkeys. Serial scans in both axial and coronal planes were used to study the onset, peak, and regression of edema. Progression of edema, predominantly involving the white matter, was analyzed from the postmortem distribution of a blood/brain barrier indicator (Evans blue) injected at surgery. Specific gravity was measured in fresh, unfixed specimens from both the edematous and normal hemispheres and correlated with corresponding CT attenuation values obtained before death. The drop in specific gravity closely corresponded to the decrease in CT attenuation.

Acute isodense epidural hematoma on computed tomography.

Computed tomography (CT) has proven to be invaluable in the diagnosis of craniocerebral injuries. Acute epidural hematomas have been described as having a characteristic appearance on CT of a lenticular shaped area of blood density most commonly situated over the cerebral convexity. This case demonstrates an acute epidural hematoma that is essentially isodense with brain tissue.

Subdural hematomas: an unusual appearance on computed tomography.

It may at times be difficult to separate supra- from infratentorial and intra- from extraaxial pathology on the basis of axial transverse computed tomography (CT) scans. Coronal CT scans may be quite useful in more accurate localization of compartments. Three head injured patients with subdural hematomas were studied with axial transverse CT scans. In addition to the typical appearance of subdural hematomas, unusually shaped areas of increased attenuation were noted in the region of the tentorium cerebelli separate from the mass of the subdural collection. Coronal scans confirmed the supratentorial, extraaxial collection as an extension of the subdural hematoma into the supratentorial subdural space.