Faculty Bibliography

We present the PET/CT findings of hemostatic absorbable gelatin (Gelfoam) in a 41-year-old woman who had hysterectomy and bilateral oophorectomy. CT showed a very low attenuation lesion (-232 HU) in the surgical bed, but PET showed no significant activity.

We present the case of a 61-year-old man who underwent I-123 metaiodobenzylguanidine (MIBG) scintigraphy based on clinical suspicion of pheochromocytoma. The study was nondiagnostic secondary to diffuse muscle uptake. On review of his medications, the patient was found to be taking mirtazapine, a tetracyclic antidepressant (Remeron). We hypothesize that the MIBG biodistribution was altered by mirtazapine-mediated blockade of the presynaptic alpha-2 receptor. To our knowledge, tetracyclic antidepressants have not been previously reported to cause altered biodistribution on I-123 MIBG scans.

BACKGROUND:Patients with primary hyperparathyroidism who undergo minimally invasive parathyroidectomy (MIP) may have postoperative symptoms of hypocalcemia or secondary hyperparathyroidism. This study sought to identify factors predictive of these events. METHODS:Between 1998 and 2004, 190 patients with primary hyperparathyroidism underwent MIP with excision of a single adenoma. Age, gender, race, prior head and neck surgery, use of preoperative thyroid hormone or calcium-channel blockers, preoperative levels of calcium, 25-hydroxyvitamin D (25[OH]D) and intact parathyroid hormone (iPTH), the presence of osteopenia or osteoporosis, intraoperative iPTH levels, and adenoma weight were evaluated by univariate analysis as predictors of postoperative symptoms of hypocalcemia and secondary hyperparathyroidism. RESULTS:None of the following were predictors of postoperative symptoms of hypocalcemia: age, gender, race, prior head and neck surgery, preoperative medications, preoperative calcium and iPTH levels, osteopenia or osteoporosis, intraoperative iPTH levels, or adenoma weight. However, patients with postoperative symptoms of hypocalcemia had significantly lower preoperative 25[OH]D levels (P = .01). Further, higher preoperative iPTH levels (P < .01) and lower preoperative 25[OH]D levels (P = .05) were associated with secondary hyperparathyroidism postoperatively. CONCLUSIONS:A low preoperative 25[OH]D level is associated with postoperative symptoms of hypocalcemia and secondary hyperparathyroidism in patients undergoing MIP. One might consider instituting empiric calcium supplementation postoperatively in patients with low 25[OH]D levels.

OBJECTIVE: Parathyroid gland localization and lateralization are important before surgery, particularly for minimally invasive parathyroidectomy (MIP) and recurrent hyperparathyroidism. We hypothesized that readings of Tc sestamibi scans with single photon emission computed tomography (SPECT) by a surgeon and nuclear medicine physician together (NMP+S) compared to a nuclear medicine physician alone (NMP alone) might affect scan interpretation accuracy. METHODS: Between May 1999 and December 2002, 127 hyperparathyroid patients had preoperative localization with sestamibi SPECT. Scans were prospectively interpreted by an endocrine surgeon and nuclear medicine physician attending together (NMP+S) and a nuclear medicine physician attending alone (NMP alone). These readings were compared to intra-operative findings, which served as the 'gold standard'. RESULTS: There were 120 patients with primary hyperparathyroidism (55 underwent MIP) and seven with secondary or tertiary hyperparathyroidism; seven patients had recurrent hyperparathyroidism. Of 127 patients, 83 had single adenomas; 27, double adenomas; 15, hyperplasia; one, MENIIA; and one, parathyroid cancer. Sensitivity and positive predictive values were 58.6% and 67.4% for NMP alone compared to 81.9% and 70.0% for NMP+S. The overall accuracy of correct localization was 45.7% vs. 60.6% (P<0.01) and of correct lateralization was 69.3% vs. 80.3% (P<0.01) for NMP alone versus NMP+S respectively. The most common finding interpreted incorrectly by NMP alone and correctly by NMP+S was an ectopic superior parathyroid adenoma in the inferior position. Ninety-eight per cent of patients were cured of their hyperparathyroidism. CONCLUSIONS: Parathyroid sestamibi SPECT scan interpretation by an endocrine surgeon reading with a nuclear medicine attending resulted in improved accuracy of gland localization and lateralization compared to a nuclear medicine attending reading alone. This improvement may be due to increased awareness of clinical factors and head-and-neck anatomy

BACKGROUND: Technetium 99m ( 99m Tc)-methoxyisobutylisonitrile (MIBI) single photon emission computed tomography (SPECT) is frequently used in the evaluation of patients with hyperparathyroidism. Calcium channel blockers (CACBs) may affect 99m Tc-MIBI uptake by parathyroid cells. This study examines the effect of CACB therapy on the sensitivity of 99m Tc-MIBI SPECT localization for hyperparathyroidism. METHODS: Two hundred fifty-three operated patients with hyperparathyroidism were retrospectively reviewed. The potential effect of CACB therapy on 99m Tc-MIBI scan sensitivity was examined by using logistic regression analysis. Possible confounding factors were considered. RESULTS: Among 235 patients, those with multiple endocrine neoplasia, type I (MEN-I), MEN-IIA, 4-gland hyperplasia, secondary hyperparathyroidism, and tertiary hyperparathyroidism exhibited no difference associated with CACB use. Of the remaining 198 patients with primary hyperparathyroidism, 7/30 (23%) with negative 99m Tc-MIBI SPECT scans compared to 24/168 (14%) with positive scans used CACBs. After correcting for age, gender and gland weight, the odds ratio (OR) for a negative study in patients taking CACBs was 2.88 (95% CI, 1.03-8.10; P = .045). Atherosclerosis, hypertension, diabetes mellitus, preoperative calcium and parathyroid hormone levels, and thyroid hormone use were not confounding factors. CONCLUSIONS: CACB therapy reduces the sensitivity of 99m Tc-MIBI parathyroid SPECT in patients with primary hyperparathyroidism. Further studies are required to determine the potential reversibility of this effect with termination of CACB therapy