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Bakheet, Hammami
Radioiodine uptake in the head and neck.Bakheet SM, Hammami MM, Powe J, Larsson S. Endocr Pract. 2000 Jan-Feb;6(1):37-41. [abstract only]
"OBJECTIVE: To report two cases of sinusitis-associated radioiodine uptake in patients with thyroid cancer and to review the reported causes of false-positive radioiodine uptake in the head and neck area.
METHODS: We present the radiologic findings in two patients who had undergone treatment for papillary thyroid cancer and discuss other settings in which radioiodine uptake suggested the presence of metastatic disease.
RESULTS: Radioiodine whole-body scans of two patients who had had thyroid cancer demonstrated uptake in the sphenoid and maxillary sinuses, respectively, mimicking bone or brain metastatic involvement. The thyroglobulin levels were low. Computed tomographic (CT) scanning disclosed mucosal swelling in the sinuses, consistent with sinusitis. The radioiodine uptake cleared on a follow-up scan in one case and was more localized than the CT findings in the other. Eighteen causes of false-positive radioiodine uptake in the head and neck area have been reported. On the basis of the mechanism of uptake, they can be classified into four categories: (1) physiologic uptake (ectopic thyroid tissue), (2) nonthyroidal pathologic conditions (dacryocystitis, sinusitis, sinus mucocele, sialadenitis, folliculitis, Warthin's tumor, parotid cyst, porencephaly, posttraumatic cerebromalacia, and inflammation due to dental disease or a nose ring), (3) internal retention (ectasia of the carotid artery and an artificial eye), and (4) external contamination by body secretions (sweat and nasal, tracheobronchial, lacrimal, and salivary secretions). The estimated prevalence of external contamination in the head and neck area on whole-body radioiodine scans is 0.3%.
CONCLUSION: Physicians should rule out the presence of radioiodine uptake by inflamed mucosa of the paranasal sinuses, as well as various other causes of false-positive radioiodine uptake, before metastatic thyroid cancer in the head and neck area is diagnosed."
Radioiodine uptake in inactive pulmonary tuberculosis.Bakheet SM, Hammami MM, Powe J, Bazarbashi M, Al Suhaibani H. Eur J Nucl Med. 1999 Jun;26(6):659-62. [abstract only]
"Radioiodine may accumulate at sites of inflammation or infection. We have seen such accumulation in six thyroid cancer patients with a history of previously treated pulmonary tuberculosis. We also review the causes of false-positive radioiodine uptake in lung infection/inflammation. Eight foci of radioiodine uptake were seen on six iodine-123 diagnostic scans. In three foci, the uptake was focal and indistinguishable from thyroid cancer pulmonary metastases from thyroid cancer. In the remaining foci, the uptake appeared nonsegmental, linear or lobar, suggesting a false-positive finding. The uptake was unchanged, variable in appearance or non-persistent on follow-up scans and less extensive than the fibrocystic changes seen on chest radiographs. In the two patients studied, thyroid hormone level did not affect the radioiodine lung uptake and there was congruent gallium-67 uptake. None of the patients had any evidence of thyroid cancer recurrence or of reactivation of tuberculosis and only two patients had chronic intermittent chest symptoms. Severe bronchiectasis, active tuberculosis, acute bronchitis, respiratory bronchiolitis, rheumatoid arthritis-associated lung disease and fungal infection such as Allescheria boydii and aspergillosis can lead to different patterns of radioiodine chest uptake mimicking pulmonary metastases. Pulmonary scarring secondary to tuberculosis may predispose to localized radioiodine accumulation even in the absence of clinically evident active infection. False-positive radioiodine uptake due to pulmonary infection/inflammation should be considered in thyroid cancer patients prior to the diagnosis of pulmonary metastases."
Radioiodine secretion in tears.Bakheet SM, Hammami MM, Hemidan A, Powe JE, Bajaafar F. J Nucl Med. 1998 Aug;39(8):1452-4.
"Lacrimal secretion of radioiodine has been suspected from previous scintigraphic observations. We semiquantitated radioiodine secretion in the tears of a thyroid-ablated patient with an artificial eye while the patient was on thyroxine treatment.
METHODS: After an oral dose of 555 MBq (15 mCi) 123I, 12 tear samples were collected over 24 hr by using Schirmer papers. Radioactivity in each sample was determined in a well counter 27 hr after radioiodine ingestion and was corrected for decay and counting efficiency.
RESULTS: Radioactivity was detectable at 15 min and at up to 24 hr after radioiodine ingestion and peaked at around 60 min (215 Bq/microl or 39 x 10(6)% of the administered dose/microl. Considering a tear-flow rate of 1 microl/min, the total radioactivity secreted in the first 4 hr was estimated to be 56 kBq, representing about 0.01% of the administered dose.
CONCLUSION: An appreciable amount of ingested radioiodine could be secreted in tears. The potential damage of the lacrimal gland after high doses of 131I treatment deserves further study."
Radioiodine uptake in the chest.Bakheet SM, Powe J, Hammami MM. J Nucl Med. 1997 Jun;38(6):984-6.
"False-positive radioiodine uptake in the chest area can be classified into four categories:
"The most common reported causes are physiological uptake by the nonlactating breast, esophageal retention of salivary secretion by an apparently normal esophagus and external contamination by body secretions. A high degree of suspicion, coupled with careful history and physical examination, is needed for proper interpretation of positive radioiodine scans."
Radioiodine bronchogram in acute respiratory tract infection.Bakheet SM, Hammami MM, Powe J. Clin Nucl Med. 1997 May;22(5):308-9. [abstract only]
"In this article, the authors described a 31-year-old woman with differentiated thyroid cancer is presented who had radioiodine uptake in the distribution of the tracheobronchial tree in association with symptoms of an acute respiratory tract infection. As expected, the uptake was transient and disappeared on the follow-up scan performed after 10 days of antibiotic treatment"
False-positive radioiodine uptake in the abdomen and the pelvis: radioiodine retention in the kidneys and review of the literature.Bakheet SM, Hammami MM, Powe J. Clin Nucl Med. 1996 Dec;21(12):932-7. Review. [abstract only]
"Because the kidneys are usually not visualized on radioiodine whole-body scans, the renal uptake can be mistaken for a thyroid cancer metastasis. The authors report the prevalence and characteristics of radioiodine retention in the kidneys and review the reported causes of false-positive radioiodine uptake in the abdomen and pelvic areas. Radioiodine uptake in the renal bed was noted on 9 of 400 (2.2%) I-123 diagnostic whole-body scans performed over a 7-month period in our center. The uptake was noted more clearly on posterior views, cleared on delayed images after further hydration, and was not consistently present on follow-up scans. It was unilateral and mimicked a renal or adrenal metastasis in 44% of the scans. In three cases, the uptake was associated with a dilated calyx, an extrarenal pelvis, or a voluminous pelvis. False-positive radioiodine uptake in the abdomen and pelvis has been previously reported in association with 14 different conditions. However, renal retention may represent the most common cause of false-positive radioiodine uptake in the abdomen pelvis. Delayed imaging after additional hydration is usually sufficient to clarify its origin."
Radioiodine breast uptake in nonbreastfeeding women: clinical and scintigraphic characteristics.Hammami MM, Bakheet S. J Nucl Med. 1996 Jan;37(1):26-31.
"We studied the scintigraphic and associated clinical characteristics of radioiodine breast uptake in nonbreastfeeding thyroid cancer patients undergoing routine whole-body radioiodine scanning.
METHODS: We performed a retrospective review of the radioiodine scans and medical records of 30 prospectively collected cases.
RESULTS: Twenty-three nonpregnant patients had discontinued breastfeeding for a mean of 11.4 mo. Three postmenopausal and four single nulliparous patients had radioiodine breast uptake on one or more occasions. This represented about 6% of all female patients who had radioiodine scans over a 3-yr period. Four patterns of uptake, full, focal, crescentic and irregular, were observed. Breast uptake mimicked lung metastasis in nine patients. Expressible galactorrhea and moderately elevated prolactin levels were present in 48% and 24%, respectively, of patients examined. In 14 patients followed for an average of 11.4 mo, there were no consistent changes in the pattern or intensity of breast uptake. In 18 patients who had both 123I diagnostic and 131I postablation scans within a few days, breast uptake was present on both scans in 75%. In four patients, breast uptake was present, despite the 4%-9% radioiodine uptake by the thyroid; in one patient, iodinated contrast material blocked the uptake of the thyroid gland but not of the breast.
CONCLUSION: Although the mechanisms of radioiodine breast uptake remain unclear, breast uptake should be suspected in all female patients with radioiodine uptake in the chest area, even in the absence of a history of breastfeeding."
Patterns of radioiodine uptake by the lactating breast.Bakheet SM, Hammami MM. Eur J Nucl Med. 1994 Jul;21(7):604-8. [abstract only]
"Breast uptake of radioiodine, if not suspected, may be misinterpreted as thyroid cancer metastasis to the lung. To characterize the patterns of radioiodine breast uptake, we retrospectively studied 20 radioiodine scans that were performed within 1 week of cessation of breast feeding. Four patterns of uptake were identified: "full", "focal", "crescent" and "irregular". The uptake was asymmetric in 60% (left > right in 45%, right > left in 15%), symmetric in 25% and unilateral in 15% of cases. A characteristic full bilateral uptake was present in 40% of cases. In three cases with the irregular pattern, caused in part by external contamination with radioactive milk, the uptake closely mimicked lung metastases. Delayed images, obtained in one case, showed an apparent radioiodine shift from the breast to the thyroid, suggesting that the presence of breast uptake can modulate radioiodine uptake by thyroid tissue. In a case of unilateral breast uptake, a history of mastitis was obtained, which to our knowledge has not been previously reported. Breast uptake of radioiodine may take several scintigraphic patterns that are not always characteristic of the lactating breast and may affect the apparent extent of thyroid remnant/metastasis."
False-positive radioiodine whole-body scan in thyroid cancer patients due to unrelated pathology.Bakheet SM, Hammami MM. Clin Nucl Med. 1994 Apr;19(4):325-9. [abstract only]
"Radioiodine whole-body scanning is the imaging modality of the highest accuracy in diagnosing metastases from differentiated thyroid cancer. However, unrelated pathology in one of several nonthyroidal tissues that normally take-up/secrete radioiodine may result in a false positive scan. The authors report cases of an ectopic kidney, chronic sinusitis, dacryocystitis, and an artificial eye, complicating differentiated thyroid cancer, that on radioiodine scanning mimicked lumbar, frontal, and left and right orbital bone metastases, respectively. The nature of the radioiodine uptake was suspected from the results of a bone scan and proven by ultrasound (ectopic kidney), by reimaging after specific treatment (chronic sinusitis, and dacryocystitis), or by postwashing reimaging (artificial eye). To our knowledge, this is the first report of such cases. Nonthyroidal pathology should be excluded before exposing patients with apparent thyroid cancer metastases that have atypical characteristics on radioiodine whole body imaging."
False-positive thyroid cancer metastasis on whole-body radioiodine scanning due to retained radioactivity in the oesophagus.Bakheet S, Hammami MM. Eur J Nucl Med. 1993 May;20(5):415-9. [abstract only]
"In patients with differentiated thyroid cancer, radioiodine uptake in the mediastinal area most often indicates thyroid cancer metastasis. We review 15 radioiodine whole-body scans showing 19 mediastinal artefacts that mimicked lymph node or spinal metastasis. The artefacts disappeared on delayed images after eating and drinking (17) or on studies repeated within 1 week (2), suggesting their oesophageal origin. No patient had clinical oesophageal or gastric disease. Only two artefacts were linear; 12 were focal and five were diffuse. Twelve artefacts were better seen on anterior views (nine in the upper, two in the middle and one in the lower mediastinal area), whereas seven were better seen on posterior views (two in the upper, two in the middle, and three in the lower mediastinal area). The 15 scans were identified from about 1000 scans performed over 24 months in our centre. We conclude that the transient presence of radioiodine in an apparently normal oesophagus may not uncommonly mimic mediastinal lymph node or spinal metastases from thyroid cancer and that its scintigraphic presentation is variable."
Spurious lung metastases on radioiodine thyroid and whole body imaging.Bakheet S, Hammami MM. Clin Nucl Med. 1993 Apr;18(4):307-12. [abstract only]
"In patients with differentiated thyroid cancer, radioiodine uptake in the area of the lung usually denotes metastasis; however, it could represent an uptake by unrelated pulmonary disease or by the breasts, or external contamination. In this study, 22 foci that simulated lung metastasis on 11 thyroid and whole body scans were proven not to be metastasis by reimaging after cleaning (15 foci), or were strongly suspected to be due to external contamination because of the features of other images (7 foci). All foci were noted only on anterior views of the chest. Of the 22 foci, 19 were focal, two were smeared, and one was lobar. Foci were multiple in 7 scans, unilateral in 10 scans, and were associated with other artifacts in 4 scans. Caution should be used in interpreting apparent pulmonary radioiodine uptake as lung metastasis; reimaging after cleaning the skin and changing garment should be obtained when the uptake is confined to anterior views of the chest and/or when its pattern is atypical."
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