Srinivas Bommireddipalli

Follicular variant of papillary thyroid carcinoma presenting as a toxic nodule by I-123 scintigraphy.

The risk of malignancy in a “hot” thyroid nodule detected by radioiodine scintigraphy is rare. We report a case of a 63-year-old man with a hyperfunctioning nodule demonstrated by radioiodine scintigraphy and cytology suspicious for follicular variant of papillary thyroid carcinoma (FVPTC). There were no locoregional or distant metastases at initial diagnosis. Histopathologic examination following thyroidectomy confirmed the presence of an encapsulated FVPTC. A year into follow-up, his I-131 whole body scan performed following the withdrawal from exogenous thyroid hormone was negative, whereas his serum thyroglobulin (Tg) levels were intermediate. A subsequent PET/CT scan revealed a small, but stable, metabolically active pretracheal lymph node, which on biopsy was confirmed to be stage III FVPTC. In conclusion, the presence of hyperfunctioning thyroid nodule(s) does not preclude malignancy and, therefore, proper cytohistologic evaluation in such patients may help to exclude a coexistent thyroid carcinoma. Patients treated for localized PTC may benefit from serial PET/CT follow-up in the early detection and management of recurrence or distant metastases.

Effect of Proton Pump Inhibitors and H2 Antagonists on the Stomach Wall in 99mTc-Sestamibi Cardiac Imaging

On the basis of previously unpublished observations, we hypothesized that prolonged use of proton pump inhibitors (PPIs) causes an increase in 99mTc-sestamibi uptake in the stomach wall, manifested as curvilinear activity surrounding the photopenic fundus of the stomach cavity. We prospectively evaluated the frequency of stomach wall uptake in patients undergoing myocardial perfusion SPECT who were taking PPIs or H2 antagonists. Methods: Patients (n = 138) who were scheduled for single-day rest/stress 99mTc-sestamibi SPECT were randomly selected. Poststress SPECT was performed 30 min after treadmill exercise or 45 min after dipyridamole infusion. The rest scan was obtained 45 min after tracer injection. All patients drank 473 mL of water 5–10 min after both the rest and the stress radiotracer injections. Patients were questioned regarding their use of PPIs and H2 antagonists. The significant use of either was defined as more than 2 wk of continuous therapy before cardiac SPECT. Masked observers assessed poststress planar projection images in endless-loop cinematic format for the following 3 patterns: stomach cavity uptake, attributable to duodenogastric reflux of tracer; stomach wall uptake; and no stomach uptake. A 2-tailed χ2 test with Yates correction was used to calculate statistically significant associations among variables. Results: Only patients with observed patterns of stomach wall uptake (n = 30) and no stomach wall uptake (n = 91) were included. Patients with stomach cavity uptake (n = 17) were excluded because the assessment of the adjacent stomach wall uptake was not possible. Of the patients included (n = 121), 30 were men and 91 were women. Sixty-seven patients were older than 60 y; 26 patients were taking PPIs. Of the 95 patients not taking PPIs, 14 were taking H2 antagonists. No patients were taking both medications. Stomach wall uptake was strongly associated with prolonged use of PPIs (χ2 = 51.9, P < 0.0001). No statistically significant association was noted among age, sex, or use of H2 antagonists (P = NS). Conclusion: Prolonged PPI therapy, but not H2 antagonist therapy, contributes to a significant increase in stomach wall activity, potentially resulting in Compton scatter or ramp filter artifacts affecting the inferior wall of the left ventricle. Stomach wall activity, unlike the stomach cavity activity, cannot be prevented by the ingestion of water before imaging. Therefore, it is important to elicit a history of prolonged PPI use to better anticipate the possibility of increased stomach wall activity, which can confound the image quality and interpretation.

FDG PET Appearance of “Cannonball” Pulmonary Metastases

We present the case of a 67-year-old woman with a recent tissue diagnosis of endometrial cancer whose FDG PET scan exhibited multiple hypermetabolic foci through out both the lungs. Contemporaneously acquired conventional radiolographs showed parenchymal nodules that demonstrated the classic “cannon ball” appearance of pulmonary metastases. Pulmonary metastasis from an endometrial primary is a rare event, as are the presence of pulmonary findings at the time of initial staging. Thus, this case demonstrates rare, and yet, distinctive aspects of the disease presentation and image correlation across the various imaging modalities.

HIV-associated lymphocytic interstitial pneumonitis causes diffuse sestamibi lung uptake in myocardial perfusion imaging

Technetium-99m (99mTc) sestamibi myocardial perfusion scintigraphy (MPI) is widely used for the diagnosis and assessment of prognosis in patients with suspected coronary artery disease. During these investigations, inspection of raw projected data for the purpose of quality control may occasionally yield incidental noncardiac findings that suggest the presence of another primary noncardiac disease. We present a 66-year-old HIV patient with a tissue diagnosis of lymphoid interstitial pneumonitis (LIP), who demonstrated a diffuse increase of 99mTc sestamibi in bilateral lung fields both in rest and stress MPI.

Spontaneous transition of an autonomously functioning thyroid adenoma to Graves' disease.

We report a case of a 57-year-old postmenopausal woman with an autonomously functioning thyroid adenoma spontaneously developing Graves’ disease (GD) as documented by I-123 scintigraphy. To date, anecdotal case reports citing the progression of an autonomous nodule to GD have documented either a major thyroidal insult, spontaneous or therapeutic, or the activation of thyroid tissue by circulating thyroid stimulating IgG, with variable progression characteristics. In contradiction to the proposed inciting factors, our patient underwent a minimally invasive fine needle aspiration biopsy followed by suppressive pharmacotherapy. Her antithyroid antibody assay detected low titers of thyroperoxidase antibody (<10 U/mL). We conclude that this is a rare case of autonomously functioning adenoma where neither significant thyroid tissue damage nor the presence of thyroid stimulating IgG can be implicated as an inciting trigger in its progression to GD.

Equilibrium radionuclide ventriculography with a large photopenic defect and displacement of the heart.

Equilibrium radionuclide ventriculography was performed in a 67-year-old woman with metastatic breast cancer. The patient was referred for baseline radionuclide ventriculography to evaluate ventricular function before initiating chemotherapy. The left anterior oblique view shows a large photondeficient area in the left lower chest extending cephalad to the level of the atria. This photopenic region appears to markedly displace the entire heart, in particular the left ventricle, to the middle of the chest (Figure 1). Otherwise, left and right ventricular volumes and regional wall motion were normal, and the left ventricular ejection fraction was 64%. The possible causes for this photopenic area were suspected to be a lung or diaphragmatic mass (primary malignancy vs metastasis), pleural effusion, atelectasis, pulmonary hypoplasia, lung resection, diaphragmatic hernia, intra-abdominal pathology, and elevated hemidiaphragm. Posteroanterior and lateral chest radiographs and a computed tomography scan of the chest (Figures 2 and 3) show a markedly elevated left hemidiaphragm that displaces the heart to the right, without other evidence of pulmonary or abdominal pathology. Radionuclide ventriculography is a useful imaging modality in the evaluation and monitoring of cardiac function in patients who receive cardiotoxic drugs. When this modality shows an unexpected heart position and associated photopenic defect, correlation with other imaging modalities, starting with chest radiographs, can be helpful to elucidate the etiology of this unexpected From the Division of Nuclear Medicine, St Luke’s Roosevelt Hospital Center, New York, NY. Reprint requests: Murali Meka, MD, Division of Nuclear Medicine, S & R 5, St Luke’s Hospital, 1111 Amsterdam Ave, New York, NY 10025; MMeka@chpnet.org. J Nucl Cardiol 2008;15:e21-e22. 1071-3581/

2.01: Quarter-time myocardial perfusion SPECT wide beam reconstruction

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