Benzodiazepine receptor deficiency and tinnitus.

As regards the symptom of a predominantly central tinnitus of the severe, disabling type, it has been hypothesized that a deficiency in the benzodiazepine receptor exists in the medial temporal lobe system of brain and is directly related to affect impairments including anxiety, stress, depression, and fear. This hypothesis has been investigated with single-photon emission computed tomography using the benzodiazepine radioligand 123I Iomazenil. Visual analysis revealed preliminary results of diminished benzodiazepine-binding sites in the medial temporal cortex of all patients with severe tinnitus (N = 6), a finding that is consistent with the hypothesis implicating GABAergic mechanisms in the pathophysiology of the disorder. An abnormal gamma-aminobutyric acid--A benzodiazepine receptor density may be an objective neurochemical measure of the severity of a central-type tinnitus and a rationale for treatment. Clinical correlation with the history, clinical course of the patient, and stress questionnaire are presented.

Tc-99m MAG3 evaluation of recipients with dual adult cadaveric renal allografts. Simultaneous transplantation of both kidneys from marginal donors.

PURPOSE: The application of Tc-99m mercaptoacetyl triglycine (MAG3) renal scintigraphy in patients who had simultaneous unilateral retroperitoneal transplant of both kidneys from marginal adult cadaveric donors is assessed. METHODS: Eighteen patients who had this unusual form of kidney transplant were monitored and evaluated by Tc-99m MAG3 renal scintigraphy. More than 60 of the radioisotopic studies, including immediate postoperative and subsequent follow-up examinations, were performed among these patients. RESULTS: In all the studies, the two transplanted kidneys were not equally well visualized by this scintigraphic procedure because of the inherent difference in their depth from the body surface, a feature of this particular surgical design. Despite this limitation, the efficacy of the scintigraphic procedure for such dual renal allografts appears to be similar to that established for kidney transplants performed in the conventional manner. CONCLUSION: To use the scintigraphic procedure effectively, certain sensible and logical adjustments are needed for the comparative visual and semiquantitative assessments of the two kidneys in this special form of transplantation.

Descending auditory system/cerebellum/tinnitus.

The cerebellum and the descending auditory system (DAS) are considered clinically significant for influencing the development of the clinical course of tinnitus of the severe disabling type. It is hypothesized that the SPECT of Brain perfusion asymmetries in cerebellum, demonstrated since 1993, reflect clinically the influence of an aberrant auditory stimulus i.e. tinnitus, on the activity and function of the descending auditory system highlighted by the cerebellum and the acousticomotor systems. SPECT of Brain perfusion asymmetries in the cerebellum have been demonstrated in 60-70% of tinnitus patients of the central type. Electrophysiologic support for this finding includes interference in ocular fixation suppression of the vestibulocular (VOR) with rotation and position testing. Abnormalities in cerebellar function are considered to reflect the psychomotor component of tinnitus. Support for the hypothesis is demonstrated with one patient with a predominantly central type tinnitus of the severe disabling type with cerebellar perfusion asymmetries and associated electrophysiologic evidence of interference in the VOR with rotation testing.

Scintigraphic demonstration of postural induced drainage stasis in an en bloc renal allograft.

Within 6 months after an en bloc transplantation of two kidneys from a cadaveric pediatric donor, the recipient was referred for further scintigraphic evaluation because of clinical suspicion of having a postural related function impairment of the grafted kidneys. Tc-99m MAG3 imaging, modified by varying the position of the patient during the procedure, resulted in detection of drainage stasis only with the patient standing. This drainage stasis had not been appreciated in the preceding routine examinations performed with the patient supine. Although the positional outflow stasis by itself may not be severe enough to cause alarming dysfunction of the grafted kidneys, it could conceivably be a significant contributing factor.

Sestamibi scan for preoperative localization in primary hyperparathyroidism.

BACKGROUND: Various invasive and noninvasive localizing tests are available for the evaluation of primary hyperparathyroidism. The surgical success in primary intervention exceeds 90% without localization studies. However, localization tests are absolutely essential for re-exploration and in certain select circumstances, even in primary exploration. The traditional noninvasive localization studies include the sonogram, thallium-technetium scan, computed tomography (CT) scan, and magnetic resonance imaging (MRI). The purpose of this report is to review our recent experience with sestamibi scan. The sestamibi scan appears to be the most sensitive and accurate noninvasive test available today. METHODS: Technetium 99m sestamibi has recently been used for parathyroid localization, in conjunction with iodine123 subtraction. We have evaluated 24 patients with suspected primary hyperparathyroidism to study the role of technetium 99m sestamibi scan. Tc-sestamibi was used either with or without iodine123 for subtraction of thyroid activity. RESULTS: None of these patients had renal failure or secondary hyperparathyroidism. Of 24 patients, the parathyroid adenoma was localized by scintigraphy in 19 patients. Twenty patients underwent surgical exploration. In 17 patients there was a complete correlation between the imaging study and the operative findings (positive predictive value, 89%). There were no false positives in this series. The interpretation of the parathyroid images was relatively easy; however, the depth of the adenoma could not be predicted, based on the scan alone. The largest adenoma weighed 2.7 g, the smallest, 700 mg. CONCLUSION: This newer radiopharmaceutical, technetium 99m sestamibi, appears to be quite useful and accurate in the preoperative localization of patients with primary hyperparathyroidism. Parathyroid enlargement can also be studied by sestamibi imaging alone if delayed imaging is performed.

Penile scintigraphy for priapism in sickle cell disease.

UNLABELLED: Penile scintigraphy with [99mTc]pertechnetate/99mTc-RBCs was performed in patients with sickle cell disease patients who had priapism to assess the role of this imaging procedure in directing the clinical management of these patients. METHODS: Fifteen studies were performed in 13 patients who were treated according to a protocol not dependent on the imaging results. The scintigraphic findings of penile vascular perfusion (stagnant or nonstagnant patterns) were collated retrospectively with the form of treatment needed for relief of the condition. RESULTS: Four of five patients with the nonstagnant perfusion pattern responded to analgesics and intravenous hydration. Four of eight patients with the stagnant pattern did not require any aggressive interventions such as corporeal aspiration/irrigation, intracorporeal epinephrine or glans-cavernosa shunt. CONCLUSION: Whereas the nonstagnant scintigraphic finding appeared to be a favorable indicator for conservative treatment, the stagnant finding was apparently noncontributory. In addition, no correlation was found between these two types of scintigraphic patterns and the subsequent sexual potency of these patients.

Pitfalls and limitations of diuretic renography.

We report five pediatric cases that illustrate the methodologic pitfalls and limitations of diuretic renography in suspected ureteropelvic junction obstruction. False-positive studies may be related to such avoidable flaws in methodology as premature diuretic administration, inadequate diuretic dose, and bladder distension, or to recent pyeloplasty. False-negative results may occur despite optimum technique, necessitating a follow-up study for confirmation.

Alternating hemiplegia of childhood: studies of regional cerebral blood flow using 99mTc-hexamethylpropylene amine oxime single-photon emission computed tomography.

Alternating hemiplegia of childhood is a rare disorder of unknown cause associated with progressive neurological deterioration. We report the results of regional cerebral blood flow studies using 99mTc-hexamethylpropylene amine oxime single-photon emission computed tomography in 3 patients. These studies were performed during the hemiplegic attacks (n = 6) and during the symptom-free periods (n = 2). Six single-photon emission computed tomographic studies performed during hemiplegic attacks consistently showed relative hyperperfusion of the contralateral cerebral hemisphere. Two single-photon emission computed tomographic studies performed during the asymptomatic phase showed normal and symmetrical cerebral perfusion. This is the first definite demonstration of unilateral increase of cerebral blood flow in alternating hemiplegia. These findings support the possibility of a relationship between the cause of alternating hemiplegia and migraine.

Reversible increased technetium-99m-HMPAO cerebral cortical activity: a scintigraphic reflection of luxuriant hyperperfusion.

A hemiparetic and aphasic patient, 3 days after acute traumatic transection of the left internal carotid artery requiring life-saving total embolic occlusion, revealed ipsilateral increased peripheral hemispheric 99mTc-HMPAO activity. Ten days postocclusion, HMPAO peripheral cortical flow normalized as hemiparesis and aphasia significantly cleared. The initial lateralized HMPAO hyperactivity pattern may reflect reactive hyperemia, a sign previously identified by contrast angiography and often associated with a better prognosis in evolving CVA. Evanescent peripheral cerebral hyperemia may represent beneficial cortical collateralization of the periinfarct area of a deeper lacunar (white matter) CVA.

Intermittent torsion: association with horizontal lie of the testicle.

The importance of making an early diagnosis of intermittent testicular torsion cannot be over-emphasized. We report on 3 patients with recurrent episodes of severe testicular pain but who were pain-free at evaluation. All 3 patients were found to have a horizontal lie of the symptomatic testicle and a normal vertical axis in the contralateral asymptomatic testicle. Scrotal exploration revealed a bell-clapper deformity in all 3 patients. A history of recurrent scrotal pain and horizontal testicular lie, even in the absence of pain at the time of physical examination, is a strong indication for exploration and bilateral testicular fixation.

Testicular scintigraphic findings two to three months after torsion. Correlation with sonography and histopathology.

A patient with a nontender testicular mass had sonographic abnormalities compatible with but not entirely typical of a chronic torsion. His scintigraphic studies, done on the same day as ultrasonography and 1 month later, revealed only findings consistent with a very mild subsiding scrotal inflammatory process. On surgical exploration and pathologic examination, it was found that he had an organizing infarct of the testicle secondary to torsion. The clinical history, diagnostic studies, and microscopic slides of the surgical specimen were reviewed. It appeared that tissue granulation and lipogranulomatous changes in the epididymis, known histologic sequelae to the unusually prolonged testicular torsion of 2-3 months, produced scintigraphic findings different from those which have been described for a late or an atrophic torsion.