The utility of 18F-fluorocholine PET/CT in the imaging of parathyroid adenomas.

INTRODUCTION: The aim of the study was to estimate the sensitivity of ¹8F-FCH PET/CT in preoperative localisation of hyperfunctioning parathyroid glands in patients with primary hyperparathyroidism (PHPT). MATERIAL AND METHODS: Sixty-five consecutive patients with PHPT, who underwent neck ultrasound (US) and 99mTc/99mTc-MIBI dual-phase parathyroid scintigraphy, were prospectively enrolled. Twenty-two patients had unsuccessful parathyroid surgery prior to the study. PET/CT scans were performed 65.0 ± 13.3 min after injection of 218.5 ± 31.9 MBq of 18F-fluorocholine (FCH). Three experienced nuclear medicine physicians assessed the detection rate of hyperfunctioning parathyroid tissue. Response to parathyroidectomy and clinical follow-up served as a reference test. Per-patient sensitivity and positive predictive value (PPV) were calculated for patients who underwent surgery. RESULTS: ¹8F-FCH PET/CT was positive in 61 patients, and negative in 4. US and parathyroid scintigraphy showed positive and negative results in 20, 45 and 17, 48, respectively. US showed nodular goitre in 31 patients and chronic thyroiditis in 9 patients. Parathyroid surgery was performed in 43 (66%) patients. ¹8F-FCH PET/CT yielded a sensitivity of 100% (95% CI: 87.99-100) and PPV of 85.7% (95% CI: 70.77-94.06). Similar values were observed in patients with chronic thyroiditis, nodular goitre, and patients after an unsuccessful parathyroid surgery. PET/CT identified hyperparathyroidism complications (kidney stones, osteoporotic bone fractures, and brown tumours) in 11 patients. CONCLUSIONS: ¹8F-FCH PET/CT effectively detected hyperfunctioning parathyroid tissue and its complications. The method showed excellent sensitivity and positive predictive value, including patients with nodular goitre, chronic thyroiditis, and prior unsuccessful parathyroidectomy. PET/CT performance was superior to neck ultrasound and parathyroid scintigraphy.

18F-FDG Positron Emission Tomography/Computed Tomography (PET/CT) for Distinguishing Tuberous Sclerosis Complex Lesions from Colon Cancer Metastases.

BACKGROUND Tuberous sclerosis complex (TSC; Bourneville-Pringle disease) is a multisystem genetic disorder manifesting as benign tumors that can affect any system. Malignant neoplasm may coexist in patients with TSC. In such cases, there are diagnostic difficulties in distinguishing between metastatic lesions and benign changes. We show the usefulness of positron emission tomography (PET) in resolving these difficulties. CASE REPORT The purpose of this article is to present the usefulness of metabolic imaging using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in distinguishing benign from neoplastic lesions in a patient with TSC. A 17-year-old female patient with TSC was referred for 18F-FDG PET/CT with suspected lung and bone metastases. The patient underwent a bilateral nephrectomy because of multiple cysts and angiomyolipomas. A colonoscopy - performed in preparation for kidney transplantation - revealed sevearal colon polyps, one of which was found to be cancerous upon histopathologic examination. A diagnosis of adenocarcinoma G3 was made and a CT scan of the chest and abdomen performed afterwards showed multiple pulmonary nodules and sclerotic bone lesions suggestive of metastases. Two 18F-FDG PET/CT scans (performed within 6 months) showed multiple nodules of 7-15 mm in diameter and changes typical of multifocal micronodular pneumocyte hyperplasia in both lungs. In the bones, we found multiple sclerotic lesions. All of the above findings showed FDG uptake at the level of the background activity which contradicted the lesions' metastatic origin. CONCLUSIONS Using the example of a 17-year-old patient with TSC, we present the usefulness of metabolic imaging using 18F-FDG PET/CT in distinguishing benign from neoplastic lesions.

Feasibility of myocardial perfusion imaging studies in morbidly obese patients with a cadmium-zinc-telluride cardiac camera.

BACKGROUND: A novel cardiac SPECT camera with cadmium-zinc-telluride (CZT) based technology has a fixed array of semiconductor detectors paired with pinhole collimators focused on the heart. Image acquisition in obese patients can be challenging because of much smaller detector field of view compared to conventional gamma cameras. The aim of this study was to evaluate the impact on high body mass on the feasibility of CZT myocardial perfusion imaging (MPI). The additional aim was to investigate the mechanism of the banana-shaped/obesity artifact, as referred to in literature, and to attempt at simulating it on a phantom study. MATERIAL AND METHODS: Study group consisted of 43 patients with morbid obesity (BMI ≥ 40 kg/m2). All these patients underwent myocardial perfusion imaging on both CZT cardiac camera and general purpose SPECT/CT gamma camera. Control group consisted of all patients who underwent myocardial perfusion imaging on CZT camera throughout one calendar year and whose BMI was lower than 40 kg/m2. In this group, all repeated studies were re-analyzed for estimating the frequency of heart mispositioning in the camera field of view. The number of studies performed was 1180. A static cardiac phantom was used to simulate a banana-shaped artifact. A series of phantom acquisitions during which the phantom position was altered in the camera field of view was performed. RESULTS: In control group, 3.7% of all cardiac scintigrams required repetition, 18.9% of which were repeated due to wrong heart positioning; median BMI in this group of patients was 36.0. A banana-shaped artifact was observed in one female patient with BMI 36.0. In morbid obesity group, 32.6% of the studies were non-diagnostic with "truncation effect" on Scan Quality Control (QC). Median BMI in patients with diagnostic scans was 42.0, while in patients with not acceptable quality control test it was 45.0 (p < 0.05). Banana-shaped artifacts were observed in 5 non-diagnostic studies. In a phantom study an artifact of banana shape was obtained when gantry was distant from the phantom and target was on the edge of the camera field of view and was slightly truncated. CONCLUSIONS: Problem with heart mispositioning during imaging on the CZT camera affects less than 1% of all performed studies. Morbid obesity is not a contraindication to perform myocardia.

The diagnostic efficacy and safety of stress-only supine and prone myocardial perfusion imaging with a dedicated cardiac gamma camera in patients with suspected or known coronary artery disease.

BACKGROUND: Myocardial perfusion scintigraphy remains one of the substantial noninvasive diagnostic methods in coronary artery disease. Recent technological advancement allowed to create novel semiconductor, dedicated cardiac gamma camera with better spatial resolution and higher energy resolution, resulting in the reduction of radiation burden and acquisition time. The aim of this study was to evaluate the efficacy and safety of stress-only supine and prone MPS with a cardiac gamma camera in patients with suspected or known coronary artery disease. MATERIAL AND METHODS: A total number of 203 consecutive patients with suspected or known coronary artery disease, who underwent MPS were enrolled in the study. The patients without perfusion abnormalities on stress supine and prone MPS scans had no rest MPS, in the remaining patients two-day stress-rest imaging was performed. The group of 160 patients with one-year follow up was subjected to final analysis. RESULTS: Stress-only protocol of myocardial perfusion imaging was performed in 72 patients, 88 patients underwent two-day stress and rest myocardial perfusion scintigraphy. In 46 out of 72 stress-only group of patients, prone study did not affect further proceedings. However, in over 1/3 of cases (26/72), prone scans resulted in abstaining from rest imaging. One year follow-up revealed no sudden cardiac deaths or myocardial infarctions in both (stress-only and stress-rest) groups. Revascularization was performed most often in the double-positive group - patients with significant ischaemia on myocardial perfusion images and chest pain or electrocardiographic changes or both during the stress test. In this double-positive group, all 11 patients had coronary angiography (two of them prior to myocardial perfusion scintigraphy), nine of them had subsequent revascularization. CONCLUSIONS: In patients with no significant perfusion abnormalities on stress scans omitting rest study is safe with very good one-year risk prognosis of acute cardiac events and allows to limit the radiation exposure and procedure duration. Additional prone acquisitions are valuable supplements in determining the decision of safe early completion of myocardial perfusion imaging.

Incidentally recognised thyroid focal uptake of 99mTc-sestamibi during stress myocardial perfusion scintigraphy.

INTRODUCTION: 99mTc-sestamibi, a radiopharmaceutical widely used in the assessment of myocardial perfusion, can be used as an indicator of thyroid disease due to its oncophilic character. The aim of this study was to establish the usefulness of performing additional examinations of radiotracer uptake in the thyroid gland during standard stress scintigraphy with sestamibi in order to identify thyroid diseases. MATERIAL AND METHODS: After a retrospective evaluation of 330 consecutive myocardial perfusion scintigraphies performed in our hospital during one year, 41 patients with a focal accumulation of 99mTc-sestamibi in the thyroid were enrolled in the study. The patients underwent clinical examinations, including thyroid ultrasonography and TSH, fT4, fT3, aTPO, TRAB, calcitonin, and CEA levels. Based on the thyroid ultrasounds, 21 patients were referred for fine-needle aspiration biopsy of the thyroid. RESULTS: An abnormal accumulation of radiotracer in the thyroid was found in 41(12.4%) of 330 patients who underwent stress cardiac scintigraphy. Thirteen (31.7%) of those patients had multinodular euthyroid goitres, 12 (29.2%) had a single thyroid nodule (including two autonomous nodules), 11 (26.8%) had autoimmune thyroid disease, and one (2.4%) had papillary thyroid carcinoma. In 12 (29.2%) with thyroid tracer uptake there was no thyroid pathology. CONCLUSIONS: Additional evaluation of radiotracer uptake in the thyroid during standard myocardial perfusion scintigraphy is a valuable tool in the detection of thyroid diseases. The additional or parallel evaluation of radiotracer uptake in the thyroid should be considered during every myocardial scintigraphy.

The Utility of Hybrid SPECT/CT Lung Perfusion Scintigraphy in Pulmonary Embolism Diagnosis.

BACKGROUND: Pulmonary embolism (PE) is diagnosed either by ventilation/perfusion (V/Q) scintigraphy or pulmonary CT angiography. One of the imaging methods used in nuclear medicine is hybrid SPECT/CT scintigraphy. OBJECTIVES: The aim of this study was to evaluate the utility of SPECT/CT(Q) scintigraphy in the diagnosis of PE and to compare SPECT/CT(Q) with planar(Q) and SPECT(Q) methods. METHODS: The study group consisted of 109 consecutive patients suspected of having PE referred for performing lung scintigraphy. The inclusion criteria were: performance of perfusion planar, SPECT and SPECT/CT scans; availability of clinical data covering a 6-month follow-up period, and D-dimer level testing. The number of eligible patients was 84. PE was reported in patients with at least 1 segmental or 2 subsegmental perfusion defects without parenchymal abnormalities on CT scans. PE was excluded when there was a normal perfusion pattern or perfusion defects were caused by lung parenchymal abnormalities or were not arranged in accordance with the pulmonary vasculature. RESULTS: Twenty-six patients (31%) had a final diagnosis of PE. The sensitivity and specificity values of each method were as follows: planar(Q) 73 and 43%, SPECT(Q) 88 and 47% and SPECT/CT(Q) 100 and 83%. SPECT/CT(Q) yielded a significantly higher diagnostic accuracy than planar(Q) (p < 0.001) and SPECT(Q) (p < 0.001) scans. CONCLUSIONS: We conclude that hybrid SPECT/CT(Q) imaging has a high diagnostic efficacy in the diagnosis of PE. Lung perfusion scintigraphy performed with a hybrid SPECT/CT device has a significantly higher sensitivity and specificity than scanning performed with the planar or SPECT technique.

ST-segment elevation in the recovery phase of nuclear exercise stress test with 99mTc-sestamibi in a patient with critical RCA stenosis and subtle systolic dysfunction in speckle tracking imaging.

An asymptomatic Caucasian male patient underwent coronary artery disease diagnostics. Standard exercise treadmill test was inconclusive, and Holter ECG study didn't show any significant abnormalities. Considering the high risk of ischemic heart disease nuclear exercise stress test was performed,which revealed ST-segment elevation in the recovery phase of the treadmill exercise test. Single photon emission computed tomography (SPECT/CT) showed myocardial perfusion abnormalities in the inferior and lateral walls of the left ventricle. Furthermore,speckle tracking imaging showed subtle left ventricle dysfunction. Finally critical stenosis in the second segment of right coronary artery was diagnosed in coronary angiography.