Development of luteinized graafian follicles in patients with karyotypically normal spontaneous premature ovarian failure.

Despite having amenorrhea and markedly elevated serum gonadotropin levels, some women with karyotypically normal spontaneous premature ovarian failure, nevertheless, have ovarian follicles that function intermittently. Graafian follicles capable of responding to these high FSH levels are faced with high serum LH levels as well, which might induce inappropriate luteinization and prevent normal follicle function. We examined this possibility using weekly blood sampling and sonography in 65 patients. Nearly 50% of our patients demonstrated ovarian follicle function [serum estradiol, > 183 pmol/L (50 pg/mL)] during a median of 4 months of observation (range, 2-6 months). However, during this observation, only 16% achieved an ovulatory serum progesterone level [> 9.5 nmol/L (3.0 ng/mL)]. We imaged an antral follicle by sonography in over 40% of patients (27 of 65), and serum estradiol was significantly greater when an antral follicle was present. The follicles in these patients were not functioning normally, however. In contrast to normal women, patients with ovarian failure had poor correlation between follicle diameter and serum estradiol. We biopsied these antral follicles in 6 patients and found luteinized Graafian follicles in all cases. Therefore, luteinized Graafian follicles account for at least 60% of the antral structures imaged (95% confidence limit). Thus, inappropriate luteinization of Graafian follicles appears to be a major pathophysiological mechanism in patients with karyotypically normal spontaneous premature ovarian failure.

Ultrasound guidance improves the success rate of internal jugular vein cannulation. A prospective, randomized trial.

STUDY OBJECTIVE: To compare conventional versus ultrasound-guided internal jugular vein cannulation techniques. DESIGN: Patients were randomly assigned to receive either conventional or two-dimensional ultrasound-guided internal jugular vein cannulation. Patients who could not be cannulated with five or fewer passes by either technique, were crossed over to the other technique. SETTING: Clinical research unit in a tertiary care center. PATIENTS: All consecutive patients who required urgent or urgent-elective internal jugular vein cannulation during the study period. INTERVENTIONS: The two-dimensional ultrasound transducer imaged all cannulation attempts. For patients randomized to ultrasound guidance, the operator viewed two-dimensional ultrasound images, and received verbal guidance from the ultrasound technician. For patients randomized to the conventional arm, two-dimensional ultrasound images were recorded without visual or verbal feedback. MEASUREMENTS AND MAIN RESULTS: Two-dimensional ultrasound was significantly better than conventional guidance in reducing the number of failed site cannulations from 6/17 (35 percent), to 0/12 (0 percent), p less than 0.05. Two-dimensional ultrasound also reduced the mean number of passes required to cannulate the vein from 3.12 to 1.75 (p less than .05), and was also successful in six/six (100) of patients who failed cannulation by conventional means (p less than 0.05). CONCLUSIONS: Intensivists can increase successful internal jugular vein cannulation using ultrasound guidance. Two-dimensional ultrasound should be considered for patients difficult to cannulate or those at high risk of cannulation complications.

Ultrasound biofeedback for speech training. Instrumentation and preliminary results.

Real-time ultrasound scanning was employed as biofeedback therapy to correct a persistent articulatory speech defect in a subject. The subject continuously imaged her tongue with a transducer placed submentally. During a speech exercise, the subject could compare her tongue's positioning and movement with an ultrasound image showing the correct tongue placement prerecorded onto video tape by a speech therapist. Preliminary results suggest that this technique could be a valuable addition to speech therapy.

Ultrasound analysis of tongue, hyoid, and larynx activity during swallowing.

Using real-time ultrasound, the motions of the tongue, hyoid bone, and larynx were monitored and timed during swallowing in ten normal subjects. A well-defined propulsive wave of the tongue was observed during swallowing a 5-cc water bolus. The body of the hyoid bone was identified on the ultrasound scan as a high echogenic area with posterior acoustic shadowing at the tongue base. As the water bolus reached the pharynx, hyoid elevation was visible. Laryngeal motion was monitored by an externally applied pressure transducer and its pressure tracing incorporated into the ultrasound video image.

Quantitative ultrasonic detection and classification of diffuse liver disease. Comparison with human observer performance.

A multiparameter ultrasonic tissue characterization system has been developed and tested on several types of diffuse liver disease. The four tissue characterization parameters used are based on the first and second order statistics of the B-scan image. Performance of the system was evaluated using receiver operating characteristic (ROC) analysis and was compared with the performance of experienced human observers viewing B-scan images. The machine-based multiparameter system achieved an area under the ROC curve (Az) of 0.88 for detection of chronic hepatitis in more than 100 proven cases of the disease. This was dramatically better than the performance of human observers (Az = .64, P less than .05) and compares favorably to the performance of other accepted diagnostic tests such as head CT and the PAP smear. For detection of Gaucher's disease, the Az for the system was .92, whereas for separating hepatitis from Gaucher's disease Az was .84. Human observers also did well at these tasks (P greater than .8) using organomegaly as their major criterion for diagnosing Gaucher's disease. For primary biliary cirrhosis the system Az was .80, for glycogen storage disease Az was .94. These results suggest that use of multiparameter tissue characterization can significantly increase the usefulness of ultrasound for evaluation of diffuse liver disease.

Results of a prospective strategy to diagnose, localize, and resect insulinomas.

Since 1982, 25 consecutive patients with benign sporadic (non-multiple endocrine neoplasia type I) insulinomas have been studied. Most were referred because either the tumor was not identified at the referring institution or the diagnosis was unclear. Each patient suffered severe neuroglycopenic symptoms for a median of 24 months before diagnosis of insulinoma, and 32% had hypoglycemic seizures. Eighteen patients (72%) had a confirmed weight gain. Each patient underwent a supervised fast until 72 hours or the onset of significant neuroglycopenic symptoms (median duration 16 hours), with serum levels of glucose (median 35 mg/dl; range 24 to 46 mg/dl), insulin (median 21 microU/ml; range 11 to 230 microU/ml), C-peptide (median 2.5 ng/ml; range 1.0 to 7.2 ng/ml), and proinsulin fraction (median 55%; range 14% to 86%) measured at the termination of the fast. Preoperative imaging with ultrasonography, computed tomography, magnetic resonance, and angiography visualized tumor in a minority of patients (26%, 17%, 25%, and 35%, respectively); in 48% of patients one or more imaging study results was positive. Selective portal venous sampling for insulin was the most informative localizing test (77% positive; no false-positive results). Tumor was resected for cure in 24 of 25 patients. Intraoperative ultrasonography identified nonpalpable tumor in seven patients and was crucial to the achievement of this high rate of surgical cure. We conclude that the diagnosis of insulinoma can be made by the results of a supervised fast, portal venous sampling is the most sensitive preoperative test for localizing insulinomas, and intraoperative ultrasonography is essential for intraoperative detection of insulinomas.

Prospective evaluation of hepatic imaging studies in the detection of colorectal metastases: correlation with surgical findings.

Nineteen patients with isolated colorectal liver metastases were preoperatively evaluated with five hepatic imaging studies. The results of these studies were correlated with operative findings. One study involved the use of EOE-13, an intravenously administered lipid contrast agent that enhances liver parenchyma on computed tomography (CT) scans (EOE-CT). Another study, arterial portography (AP-CT), was performed with injection of a water-soluble contrast agent into the superior mesenteric artery during CT scanning. Delayed CT scanning (DS-CT) was completed 4 hours after AP-CT. In addition, T1- and T2-weighted magnetic resonance imaging (MRI) (T1-MRI, T2-MRI) scans were done. All patients subsequently underwent laparotomy with identification of 78 lesions. A lesion-by-lesion analysis revealed that the sensitivity of EOE-CT (83%), AP-CT (78%), DS-CT (82%), and T1-MRI (84%) was comparable. T2-MRI had a significantly lower sensitivity (64%) compared with EOE-CT, DS-CT, and T1-MRI. The false-positive rate for AP-CT was 31%, which was significantly higher than that of all other studies. The T1-MRI examination had the lowest false-positive rate and proved to be the best hepatic imaging study in the detection of colorectal metastases. EOE-CT and DS-CT were comparable, whereas AP-CT and T2-MRI proved to be inferior tests.

Localization of an occult insulinoma by intraoperative ultrasonography.

Intraoperative ultrasonography has not been used previously to locate an insulinoma that was not surgically palpable or that could not be seen by selective arteriography. In this report we described a patient with an insulinoma localized to the pancreatic head identified by transhepatic portal venous sampling but not by selective arteriography or palpation. At operation intraoperative ultrasonography demonstrated an 8 mm tumor in the pancreatic head and guided the successful enucleation.

Ultrasound and sestamibi scan as the only preoperative imaging tests in reoperation for parathyroid adenomas.

BACKGROUND: In an effort to determine an efficient algorithm for the evaluation of patients with parathyroid adenomas in the reoperative setting, we explored the combination of using ultrasound scans (US) and sestamibi scintigraphy as the only preoperative imaging tests. METHODS: We analyzed the outcomes of 62 consecutive patients who were treated between January 1995 and May 1999 and who were referred for persistent primary hyperparathyroidism after initial surgical exploration, at which time no abnormal parathyroid glands had been found. Although all patients underwent US, computed tomography scan, magnetic resonance imaging, and sestamibi scan, we analyzed the success of localization and reoperation using only the results of US and sestamibi scan. RESULTS: Sixty-one patients (98%) underwent curative reoperations. The sensitivity, positive predictive value, and accuracy for US were 90%, 86%, and 84%, respectively; the corresponding values for sestamibi imaging were 78%, 94%, and 74%, respectively. In 58 of 62 cases (94%) preoperative US and/or sestamibi scan accurately identified the adenoma. In 3 patients for whom combined US and sestamibi scan were inaccurate, 1 adenoma was found by intraoperative US in the strap muscle; 1 adenoma was found by blind cervical thymectomy, and 1 adenoma was found by planned sternotomy that was based on computed tomography findings. CONCLUSIONS: This study supports an algorithm of obtaining US and sestamibi scan as the initial and perhaps only preoperative localization tests for patients with primary hyperparathyroidism after failed operation, at which time no abnormal glands had been found.

Use of preoperative fine-needle aspiration in patients undergoing reoperation for primary hyperparathyroidism.

BACKGROUND: Neck reexploration for primary hyperparathyroidism has a lower success rate and greater morbidity than initial exploration because of scarring and distortion of tissue planes and the possibility of a parathyroid neoplasm located in an ectopic or unusual position. Although the use of standard noninvasive imaging studies for reoperative parathyroid surgical procedure is well accepted, the use of invasive studies to localize parathyroid neoplasms, particularly percutaneous aspiration of potential lesions, is controversial. In this report we analyze the results and morbidity in patients undergoing fine-needle aspiration before neck reexploration. METHODS: From 1982 to 1993, 255 patients underwent reexploration for persistent or recurrent hyperparathyroidism at the National Institutes of Health. Of these 255 patients 42 underwent 44 preoperative fine-needle aspirations by ultrasonography or computed tomography guidance in an attempt to localize a parathyroid neoplasm. The aspirated contents were then analyzed for parathyroid hormone content. RESULTS: Of the 44 aspirations 26 (59%) were true positives with no false positives. Of 18 negative fine-needle aspirations, 11 (25%) were false negatives, and seven (16%) were true negatives. The specificity and sensitivity of percutaneous fine-needle aspiration were 100% and 70%, respectively. CONCLUSIONS: Percutaneous fine-needle aspiration for parathyroid hormone is a safe, well-tolerated technique that is highly specific and allows a directed surgical resection avoiding further invasive workup when the aspirate is positive.

Localization and operative management of undescended parathyroid adenomas in patients with persistent primary hyperparathyroidism.

BACKGROUND: Between 5% and 10% of patients who undergo cervical exploration for primary hyperparathyroidism will have persistent or recurrent hyperparathyroidism. Many of these patients have parathyroid tumors in unusual locations. One such site of ectopic parathyroid tissue is an undescended parathyroid adenoma at or superior to the carotid bifurcation. We describe our experience with the preoperative localization and surgical management of undescended parathyroid adenomas. METHODS: From 1982 to 1993 a consecutive series of 255 patients have undergone localization studies and surgical exploration for persistent or recurrent hyperparathyroidism at the Clinical Center of the National Institutes of Health. Operative strategy was determined by review of the patient's surgical history, disease reports, and data from localizing studies. Patients with an undescended parathyroid adenoma identified before the operation were examined with a direct approach high in the neck. Patients who did not have definitive preoperative localization were explored with the previous transverse cervical incision. RESULTS: Seventeen undescended parathyroid adenomas were identified in 255 patients. Thirteen (76%) of 17 patients had an undescended parathyroid adenoma precisely localized before the operation and were examined via a limited, oblique incision high in the neck anterior to the sternocleidomastoid muscle. In the 13 patients who had undergone accurate localization before the operation, the median operative time was 75 minutes compared with 235 minutes for four patients who did not have an undescended parathyroid adenoma identified before the operation and were examined via a previous transverse cervical incision. All patients were cured of their hyperparathyroidism. CONCLUSIONS: Undescended parathyroid adenomas were the cause of failed cervical exploration in 17 (7%) of 255 patients. Accurate preoperative localization of these lesions is possible in most cases with a combination of noninvasive and invasive modalities. Successful preoperative localization can convert a prolonged exploration of the neck and mediastinum into a brief, curative procedure with minimal morbidity.

A randomized, prospective trial of postoperative somatostatin analogue in patients with neuroendocrine tumors of the pancreas.

BACKGROUND: Pancreatic surgery is not uncommonly complicated by prolonged pancreatic drainage and fistula. Octreotide decreases pancreatic exocrine function and has been reported to improve closure of pancreatic and intestinal fistulae. This randomized, prospective trial was designed to evaluate the efficacy of postoperative octreotide in reducing pancreatic drainage and complications after resection of neuroendocrine tumors of the pancreas. METHODS: Patients with neuroendocrine tumors of the pancreas were entered into the study and randomized after operation to receive octreotide 150 micrograms subcutaneously every 8 hours or saline solution subcutaneously every 8 hours in a double-blinded fashion. Daily pancreatic drainage, total drainage, number of days to drain removal, and complications were recorded. RESULTS: Ten patients were given octreotide; eleven patients were given saline solution. The number of days to drain removal, daily drainage, and total drainage were not significantly different. Complications related to pancreatic drainage were not significantly different. CONCLUSIONS: Octreotide is not indicated for the routine postoperative management of patients with neuroendocrine tumors of the pancreas.

Intraarterial calcium stimulation and intraoperative ultrasonography in the localization and resection of insulinomas.

BACKGROUND: Standard imaging studies (computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, ultrasonography, and angiography) correctly localize insulinomas in less than 50% of patients and provide no information about the feasibility of enucleation based on proximity of tumor to pancreatic duct. We reviewed our experience with intraarterial calcium stimulation (Ca-Stim) and intraoperative ultrasonography (IOUS) to localize and guide management of insulinomas. METHODS: Thirty-six patients (14 men, 22 women, median age 44 years) with insulinomas were treated between August 1989 and June 1996. Preoperative imaging studies were obtained. Patients underwent abdominal exploration with IOUS. Fourteen were evaluated by a surgeon blinded to preoperative imaging results. RESULTS: Tumors (4 to 50 mm) were resected by enucleation (67%) or partial pancreatectomy (33%); all were cured. Sensitivities of computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, ultrasonography, angiography, and Ca-Stim in localizing insulinomas were 24%, 45%, 17%, 13%, 43%, and 94%, respectively. Tumors were identified by blinded surgical exploration with IOUS in 12 of 14 patients (86%). CONCLUSIONS: All insulinomas were identified before operation; however sensitivity of individual noninvasive tests was low (less than 50%). In contrast, Ca-Stim was correct in 94% of cases, thus allowing a focused pancreatic exploration and obviating use of blind distal pancreatectomy. IOUS can then be used to guide safe enucleation.

Operative management of islet-cell tumors arising in the head of the pancreas.

BACKGROUND: Pancreatic islet cell tumors (ICTs) can be treated by enucleation or pancreatic resection. We reviewed our experience with ICTs in the head of the pancreas to define indications for enucleation versus pancreaticoduodenectomy. METHODS: Between January 1982 and December 1997, 48 patients underwent surgical resection for presumed ICTs of the pancreatic head. Of these, 18 were found on pathologic examination to be disease in a lymph node. Thirty patients had 32 true pancreatic head ICTs. We reviewed the operative results and postoperative courses in these patients. RESULTS: Mean diameter of the ICTs was 15 mm. Twenty-seven patients (90%) underwent successful enucleations. Three patients failed enucleation and underwent pancreaticoduodenectomy. There was no operative mortality. The median time to regular diet was 7 days. The median time to removal of all drains was 22 days. The most common complication was pancreatic fistula (15%). No patient required reoperation for treatment of a fistula. CONCLUSION: Most ICTs of the pancreatic head can be removed with enucleation, preserving pancreatic tissue and avoiding the morbidity of pancreaticoduodenectomy. The primary indication for pancreaticoduodenectomy is not the size of the lesion but its proximity to the pancreatic duct.

Early fetal movement: a real-time ultrasound study.

A single-transducer mechanical sector scanner was used to examine the first-trimester fetus. Fifty-six examinations of 31 patients demonstrated an orderly developmental progression of fetal activity beginning with beating of the fetal heart (7 weeks), progressing to fetal trunk movement (8 weeks), and culminating in individual fetal limb movement (9 weeks). The mechanical sector real-time scanner is capable of providing a high-resolution image of the first-trimester fetus and the earliest fetal movements.

Phase I trial of photodynamic therapy in the treatment of recurrent superficial transitional cell carcinoma of the bladder.

OBJECTIVES: A Phase I trial of photodynamic therapy (PDT) in the treatment of superficial transitional cell carcinoma (TCC) of the bladder was performed. METHODS: Twenty patients with recurrent superficial TCC of the bladder after receiving a mean of 2.6 (range 1 to 6) courses of intravesical therapy were treated with PDT. The photosensitizer Photofrin II dose was 1.5 or 2.0 mg/kg. A 630-nm intravesical red laser was used to activate the photosensitizer 2 days after administration of Photofrin II. A 0.01% intralipid solution was used as a bladder-filling medium to scatter light and achieve more homogeneous light distribution. Light doses from 5.1 to 25.6 J/cm2 (total dosage 1500 to 5032 J) were used to illuminate the bladder. RESULTS: Twenty patients underwent 21 treatments with PDT. Complications included asymptomatic reflux in 4 patients. One other patient, treated at the highest total light dose, experienced bladder contraction and fibrosis. Nine patients (45%) had no tumor evident at cystoscopy, on random biopsies, or in urinary cytology at the 3-month evaluation after treatment. Four patients remained without recurrent disease for 23 to 56 months. Sixteen of 20 (80%) patients experienced recurrence, and 8 of the 16 underwent cystectomy. CONCLUSIONS: An intravenous photosensitizer dose of 1.5 mg/kg Photofrin II followed by light energy in the range of 13 J/cm2 (total light dose 2500 to 3250 J) was defined as a safe treatment parameter and resulted in tumor responses. With present technologies, administration of PDT requires careful dosimetry.

Efficacy of a gonadotropin-releasing hormone agonist in the treatment of uterine leiomyomata: long-term follow-up.

The authors employed a gonadotropin-releasing hormone agonist (GnRH-a) (D-His6-pro9-NET-GnRH) to treat 19 patients with symptomatic uterine leiomyomata, by daily subcutaneous injections (4 micrograms/kg) for 6 months. After therapy, patients were followed for 6 months without any therapy. Uterine volumes were measured by serial pelvic examinations and pelvic sonography. Measurements of serum estradiol, luteinizing hormone, and follicle-stimulating hormone were used to assess treatment response. Pituitary desensitization and hypoestrogenemia were achieved in all within 8 weeks, and in 18 of 19, hypoestrogenemia was maintained for the duration. Uterine volume at the conclusion of therapy (207.5 +/- 152.7 ml) was significantly reduced in all patients when compared with pretreatment sizes (420.8 +/- 276.4, P less than 0.05). Side effects included hot flashes (78%), vaginal dryness (32%), and transient frontal headaches (55%). All patients reported partial or complete relief from their symptomatic leiomyomata. Uterine volume at the conclusion of follow-up (345.4 +/- 195.7 ml) was greater than at the conclusion of therapy. Menses resumed in all patients within 4 to 8 weeks. In conclusion, GnRH-a therapy does not provide definitive therapy for symptomatic uterine leiomyomata but is effective in reducing the size of leiomyomata as a temporary measure. Gonadotropin-releasing hormone agonist therapy may be useful as an adjunct before myomectomy or hysterectomy and deserves further investigation.

Long-acting gonadotropin hormone-releasing hormone analog used to treat uteri.

Because the size of leiomyomata uteri often decreases significantly after menopause, the authors elected to employ a long-acting gonadotropin hormone-releasing hormone analog (GnRH-alpha) (imbzl-D-His6-Pro9-Net-GnRH) to create a state of pseudomenopause in six patients with leiomyomata uteri diagnosed on the basis of pelvic examination and confirmed by pelvic ultrasonography. Patients received daily, subcutaneous injections of GnRH-alpha (4 micrograms X kg-1 X 24 hour-1) for 6 months. Uterine size (13.8 +/- 4 weeks [mean +/- standard deviation (SD), n = 6]) was determined by pelvic examination and uterine volume (533.9 +/- 394 ml [mean +/- SD, n = 6]) was determined by pelvic ultrasonography before medical therapy was begun. They observed a decrease in uterine size by pelvic examination within 4 weeks of the initiation of therapy, and all patients experienced a decrease in uterine size (9.5 +/- 4 weeks [mean +/- SD, n = 6]) (P less than 0.05) within 8 weeks of initiation of therapy. After 6 months of therapy, uterine size was 229.5 +/- 145 ml (mean +/- SD, n = 6). During treatment, plasma estrogen concentrations were assessed intermittently (every 1 to 4 weeks) and remained less than 4 pg X ml-1 throughout the period of therapy. All six patients have discontinued therapy. There has been no increase in uterine size in these patients for a period from 3 to 7 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment.

The mechanisms previously proposed for the progression of syringomyelia associated with Chiari I malformation of the cerebellar tonsils are controversial, leave many clinical observations unexplained, and underlie the prevalence of different operations currently used as initial treatment. To explore the mechanism of syringomyelia progression in this setting, the authors used anatomical and dynamic (phase-contrast and phase-contrast cine) magnetic resonance (MR) imaging, and intraoperative ultrasonography to examine the anatomy and dynamics of movement of the cerebellar tonsils, the wall of the spinal cord surrounding the syrinx, and the movement of cerebrospinal fluid (CSF) and syrinx fluid at rest, during the respiratory and cardiac cycles, and during Valsalva maneuver in seven affected patients. In all patients the cerebellar tonsils occluded the subarachnoid space at the level of the foramen magnum. Syringomyelia extended from the cervical to the lower thoracic segment of the spinal cord. No patient had evidence of a patent communication between the fourth ventricle and the syrinx on anatomical MR images, dynamic MR images, or intraoperative ultrasound studies. Dynamic MR images of three patients revealed abrupt downward movement of the spinal CSF and the syrinx fluid during systole and upward movement during diastole, but limited movement of CSF across the foramen magnum during the cardiac cycle. Intraoperative ultrasound studies demonstrated abrupt downward movement of the cerebellar tonsils during systole that was synchronous with sudden constriction of the spinal cord and syrinx. Decompression of the foramen magnum was achieved via suboccipital craniectomy, laminectomy of C-1 and C-2, and dural grafting, leaving the arachnoid intact. Immediately after surgery, the pulsatile downward thrust of the tonsils and constriction of the spinal cord and syrinx disappeared. Syringomyelia resolved within 1 to 6 months after surgery in all patients. Observations by the authors suggest the following previously unrecognized mechanism for progression of syringomyelia associated with occlusion of the subarachnoid space at the foramen magnum. The brain expands as it fills with blood during systole, imparting a systolic pressure wave to the intracranial CSF that is accommodated in normal subjects by sudden movement of CSF from the basal cisterns to the upper portion of the spinal canal. With obstruction to rapid movement of CSF at the foramen magnum, the cerebellar tonsils, which plug the subarachnoid space posteriorly, move downward with each systolic pulse, acting as a piston on the partially isolated spinal CSF and producing a systolic pressure wave in the spinal CSF that acts on the surface of the spinal cord.(ABSTRACT TRUNCATED AT 400 WORDS)

Intraoperative ultrasound-directed resection of pituitary tumors.

Microadenomas of the pituitary vary in size, particularly those related to Cushing's disease. They are often not visualized on preoperative magnetic resonance (MR) imaging and may be difficult to find during surgical exploration of the pituitary. To enhance intraoperative localization of pituitary adenomas, we assessed the feasibility of using ultrasound to detect and localize pituitary tumors. Intraoperative ultrasound (IS) in the axial and sagittal planes was performed with an Intrascan system using a 12-MHz mechanically oscillating, end-firing transducer. Interpretation of the scans was performed by two individuals, who were usually blinded to the results of preoperative MR imaging or petrosal sinus sampling. Twenty-eight patients were examined. Eighteen of these patients had microadenomas (1.5-7 mm), all with Cushing's disease; nine had macroadenomas (10-20 mm), three of which were adrenocorticotropic hormone-secreting, three growth hormone-secreting, two thyroid-stimulating hormone-secreting, and one nonfunctioning; and one patient had an intrasellar craniopharyngioma. Normal sellar and parasellar structures, such as intrapituitary cysts, the intracavernous carotid arteries, and the diaphragma sella were easily visualized. Twenty-three of the 28 tumors, including 13 of the 18 microadenomas, were detected on IS (82% sensitivity). Tumors were seen as hyperechoic masses in 19 patients, mixed echogenicity in three, and isoechoic in one. In most macroadenomas IS allowed visualization of the interface between the tumor and the normal pituitary gland. These results indicate the potential of IS to aid the intraoperative localization and definition of pituitary tumors.