Ashwani Sood

Comparison of 18F-FDG and 68Ga DOTATATE PET/CT in localization of tumor causing oncogenic osteomalacia.

Background Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome, usually caused by small benign mesenchymal tumors. The localization of these tumors is challenging, however, essential for the management. We compared the utility of 18F-FDG PET/CT and 68Ga DOTATATE PET/CT to detect the site of primary tumor in patients with suspicion of TIO. Patients and Methods Retrospective analysis of 6 patients with hypophosphatemic osteomalacia and suspicion of TIO was performed. 68Ga DOTATATE PET/CT study was performed in all 6 patients to localize the tumor. 18F-FDG PET/CT was performed in 4 of 6 patients. 18F-FDG and 68Ga DOTATATE PET/CT studies were performed within 1 week of each other. Both studies were interpreted blindly without the knowledge of other imaging findings. Results All patients had symptoms of osteomalacia and hypophosphatemia. All except 1 patient had increased level of fibroblast growth factor 23. The lag time (symptoms to PET diagnosis) ranged from 1.5 to 22 years. In 4 patients, where both studies were performed, 18F-FDG and 68Ga DOTATATE PET/CT were able to localize the tumor in 2 and 3 patients. 68Ga DOTATATE PET/CT detected tumor in 5 (83.3%) of 6 patients. Conclusions 68Ga DOTATATE PET/CT performed better than 18F-FDG PET/CT and is useful in the detection of tumors causing oncogenic osteomalacia. Therefore, in clinically suspected cases of hypophosphatemic osteomalacia, 68Ga DOTATATE PET/CT may be performed as first-line imaging investigation to avoid delay in the treatment of this devastating but curable disease. However, further studies with large patient population are warranted to validate our data.

Thyroid scintigraphy in detecting dual ectopic thyroid: A review

Dear Sir, The thyroid gland is the first endocrine gland to develop during embryogenesis on approximately 24th day of gestation. The developing thyroid is anatomically related to the developing heart, and it is pulled caudally to its definitive location in the anterior neck with the descent of heart. The thyroid completes its descent on reaching anterior to the trachea in the lower neck in the seventh gestational week. The development defects or aberrant migration of the thyroid descent will lead to ectopy of the thyroid. The Foxe 1 mutation is also shown to be associated with molecular pathology of ectopic thyroid in mouse models; however, till date, no known gene for human ectopic thyroid has been demonstrated [1]. An ectopic thyroid gland may occur anywhere along the path of initial descent of the thyroid. The most commonly found ectopic thyroid tissue is at the base of the tongue, i.e. lingual thyroid, which accounts for 90% of the reported cases. Other rare sites for ectopic thyroid are the sublingual, cervical, mediastinal, intracardiac and abdomen [2]. Most of the times, ectopic thyroid might be the only functioning thyroid tissue. Ectopic thyroid is a rare anomaly. It is further uncommon for two distinct ectopic thyroid tissues to be present simultaneously. The web search of Pubmed in English literature revealed only 26 cases of dual ectopic thyroid so far. In this letter, we describe a patient of dual ectopic thyroid where the Tc-pertechnetate thyroid scan clinched the diagnosis and led to correct management. The literature available on dual ectopic thyroid tissue is also being discussed. A 7-year-old girl presented with history of progressive midline swelling of the neck for 1 year. There was no history of pain, fever, pressure or obstructive symptoms and change in voice. Patient did not have any feature of hypo-thyroidism or hyper-thyroidism. Local examination revealed a midline neck swelling of 1.5×1 cm in size, soft in consistency, non-translucent in nature, which moved on tongue protrusion and swallowing. The oral examination showed another small irregular swelling of about 1 cm size near the base of the tongue, which was soft to firm on touch and non-tender (Fig. 1). Her thyroid function tests were suggestive of sub-clinical hypo-thyroidism with value of T3—75 ng/dL (normal=75–210), T4—4.30 μg/dL (normal=4–11) and thyroid-stimulating hormone (TSH)— 17.88 μIU/mL (normal=0.55–5.0). Based on clinical and biochemical examination, a diagnosis of ectopic thyroid was made, and the patient was referred for thyroid scan for confirmation. The thyroid Tc-pertechnetate scan demonstrated two distinct focal areas of radiotracer uptake in the sublingual and subhyoid region and no uptake in region of the thyroid bed (arrows; Fig. 2). A final diagnosis of dual ectopic thyroid was made based on thyroid scan findings. Eur J Nucl Med Mol Imaging (2008) 35:843–846 DOI 10.1007/s00259-007-0672-2

Comparative Effectiveness of Ultrasonography, 99mTc-Sestamibi, and 18F-Fluorocholine PET/CT in Detecting Parathyroid Adenomas in Patients With Primary Hyperparathyroidism

Purpose Accurate preoperative localization of parathyroid lesion(s) is crucial for successful surgical management of primary hyperparathyroidism (PHPT). This study was conducted to compare the effectiveness of ultrasonography (USG) of the neck, 99mTc-sestamibi (MIBI) imaging with or without SPECT/CT, and 18F-fluorocholine (FCH) PET/CT imaging in the preoperative localization of parathyroid lesions in patients with PHPT. Methods Fifty-four consecutive patients with PHPT were included in this prospective study who underwent preoperative localization of the parathyroid lesion(s) using 3 diagnostic modalities followed by surgery. The sensitivity, positive predictive value, and accuracy of the 3 imaging procedures to accurately detect abnormal parathyroid glands were determined using histopathology as criterion standard with postoperative biochemical response confirmation. Results 18F-fluorocholine PET/CT detected 52 of 54 patients and 52 of 56 lesions with histopathologically proven parathyroid adenomas on patient-based and lesion-based analysis, respectively. Preoperative USG, MIBI, and FCH PET/CT localized abnormal parathyroid gland(s) in 39 (72.2%), 43 (79.6%), and 54 (100%) patients, respectively. The sensitivity and positive predictive value were 69.3% and 87.1% for USG, 80.7% and 97.6% for MIBI, and 100% and 96.3% for FCH PET/CT. The accuracy was 62.9%, 79.6%, and 96.3% for USG, MIBI, and FCH PET/CT, respectively, in patient-wise analysis. In 6 patients with ectopic lesions, FCH PET/CT demonstrated higher sensitivity and accuracy than MIBI and USG (100% vs 66.6% and 16.7%, respectively). Conclusions Among the 3 imaging techniques tested simultaneously, FCH PET/CT was superior for accurate preoperative localization of parathyroid adenomas, especially for ectopic or small parathyroid lesions.

Added value of Spect/ct over planar Tc-99m mebrofenin hepatobiliary scintigraphy in the evaluation of bile leaks

ObjectiveTo determine the added value of single-photon emission computed tomography/computed tomography (SPECT/CT) over planar hepatobiliary scintigraphy (HBS) in suspected cases of bile leak. Materials and methodsAn analysis of the data of all patients who had undergone HBS for suspected bile leak during the last 3 years was carried out. All patients had undergone an initial 45 min dynamic study after an intravenous injection of Tc-99m mebrofenin, following which they underwent multiple static imaging studies for up to 24 h and SPECT/CT imaging whenever needed. ResultsA total of 203 patients had undergone an HBS for evaluation of a suspected bile leak. HBS was positive for bile leak in 110 patients, among whom 42 had undergone additional SPECT/CT. In 32 patients SPECT/CT was useful in (i) defining the exact location of collection [intracapsular vs. extracapsular vs. intraparenchymal leak (n=18/25)], (ii) defining the extent of intraparenchymal collections (n=6/6), (iii) characterizing large abdominal collections (n=2/2), and (iv) characterizing suspected contamination (n=4/4), (v) suspected collection (n=0/3), (vi) and other miscellaneous conditions (n=2/2). Defining the extent and exact localization of collection can have therapeutic implications such as the accurate site of placement of the drain for drainage. In approximately one-third of the bile leak-positive HBS studies (32/110), SPECT/CT images were helpful for better characterization of biliary collection. In all, 76% (32/42) of the SPECT/CT studies were found to provide additional useful information over planar imaging. ConclusionHybrid SPECT/CT offers the unique advantage of combining the anatomical information from CT with the functional information provided by HBS. It is most useful in characterization of biliary collections, which give important scintigraphic evidence of the severity of bile leak with therapeutic implications such as placement of a drain or surgical exploration.

Multiple Brown Tumors Caused by a Parathyroid Adenoma Mimicking Metastatic Bone Disease from Giant Cell Tumor.

Brown tumor affects multiple bones in the body with variable clinical symptoms, which may be misdiagnosed as multiple bone metastases or primary bone tumor. In the present case report, we report the usefulness of 99mTc-MDP bone scan and 99mTc-MIBI whole body scan in differentiating brown tumor of hyperparathyroidism from giant cell tumor.

Role of scintimammography in assessing the response of neoadjuvant chemotherapy in locally advanced breast cancer.

Locally advanced breast cancer (LABC) is a common cancer in the developing countries. Neoadjuvant chemotherapy (NACT) is a very important step in the treatment of such tumors and hence that the disease can be down staged and made amenable for surgery. All the tumors do not respond to the therapy equally. Hence, it becomes very important to predict the response of chemotherapy in such cases. This study evaluated the role of scintimammography in assessing the response to NACT in 23 patients with LABC. Histologically proven 23 patients of LABC were recruited in this study. Prechemotherapy tumor size was measured clinically in all patients and technitium (Tc)-99m sestamibi test was performed before NACT for each patient. Early (10 min) and delayed (2 h) image of the breast were acquired in anterior and lateral views after Tc-99m sestamibi intravenous injections and wash out rate (WOR) was computed. After 3-4 cycles of chemotherapy, surgery in the form of modified radical mastectomy was performed in 20 out of 23 patients (3 patients lost to follow-up) with pathologic evaluation of the residual tumor size. The pretherapy Tc-99m sestamibi WOR ranged from 8.3% to 68% with mean ± SD of 34.5% ±16.5%. The prechemotherapy Tc-99m sestamibi study predicted chemoresistance (WOR >45%) in 6 out of 20 patients and no chemoresistance (WOR <45%) in 14 out of 20 patients. When the WOR cut-off was set at >45%, the predictivity of the test was indicated by sensitivity of 91.7%, specificity of 62.5%, positive predictive value of 78.6%, and negative predictive value of 82.3% with a likelihood ratio of 0.1. Tc-99m sestamibi WOR is a reliable test for predicting tumor response to NACT. WOR >45% is highly predictive of chemoresistance with likelihood ratio of 0.1 than WOR <45% being predictive of chemoresponsiveness.

Diffuse hepatic and splenic Tc-99m MDP tracer uptake in case of multiple myeloma

Tc-99m methylene diphosphonate (MDP) bone scintigraphy has long been used for the evaluation of benign as well as malignant skeletal conditions. However, non-osseous tracer uptake on a bone scan is an unusual finding. There is a need to understand the pathophysiological basis of the non-osseous uptake, which may have a clinical relevance or deteriorating effect on the quality of the bone scan. We describe a case of multiple myeloma, where extraosseous uptake in the form of diffuse hepatic and splenic uptake, with almost normal skeletal tracer distribution, has been seen on the bone scan.

Substantial Increase in Myocardial FDG Uptake on Interim PET/CT May Be an Early Sign of Adriamycin-Induced Cardiotoxicity.

Cumulative cardiotoxicity is a well-established adverse effect of Adriamycin therapy. Although dose dependent, cardiotoxicity has been recently reported to occur even at lower doses than usually proposed. Conventional imaging detection and/or clinical manifestation of the deterioration in cardiac function occur late in the process; thus, it is desirable to have noninvasive markers to detect toxicity at an early stage. Several biochemical markers including troponin and atrial natriuretic peptide were explored for this purpose. The present case depicts that a significant increase in myocardial FDG uptake on posttherapy PET/CT can be a potential imaging biomarker of Adriamycin-induced cardiotoxicity.

Differential uptake of Tc-99m DMSA and Tc-99m EC in renal tubular disorders: Report of two cases and review of the literature

Tc-99m DMSA and Tc-99m EC studies are invaluable functional imaging modalities for renal structural and functional assessment. Normally, the relative renal function estimated by the two methods correlates well with each other. We here present two patients with renal tubular acidosis who showed impaired/altered DMSA uptake with normal EC renal dynamic study depicting the pitfall of DMSA imaging in tubular disorders. The two presented cases also depict distinct pattern of Tc-99m DMSA scintigraphic findings in patients with proximal and distal renal tubular acidosis, thus highlighting the factors affecting DMSA kinetics.

Palliative radiation in primary squamous cell carcinoma of thyroid: A rare case report

Primary squamous cell carcinoma of the thyroid is an extremely rare neoplasm with aggressive behavior. Until date, only around 60 cases have been reported in the literature. Primary treatment of the patient is radical surgery. With optimum treatment survival is not more than 6 months in this aggressive malignancy. However in our patient surgery it was not possible because of unresectability of the mass due to encroachment of major vessels. Hence, we have delivered radiotherapy alone, with which effective palliation could be achieved and patient is leading a good quality-of-life for last 1 year.