Thyroid incidentalomas on fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography: incidence, malignancy risk, and comparison of standardized uptake values.

INTRODUCTION: To determine the incidence of fluorine-18-fluorodeoxyglucose (FDG) avid thyroid incidentalomas detected on positron emission tomography (PET) with integrated computed tomography (CT), and correlate the FDG-PET-CT findings to cytology. METHODS: A total of 942 FDG-PET-CT reports were retrospectively reviewed. Patients with FDG-avid thyroid incidentalomas were further reviewed for correlative cytology. RESULTS: The incidence of FDG-avid thyroid incidentalomas is 2.2%. Thyroid malignancies were identified in 3 of 6 patients who underwent cytologic correlation, with a positive predictive value of 50% (95% confidence interval, 14%-86%). The mean maximum standardized uptake values of benign and malignant FDG-avid thyroid incidentalomas were 5.6 and 6.6, respectively. CONCLUSION: A FDG-avid thyroid incidentaloma may predict underlying malignancy. Cytologic assessment should be considered for FDG-avid thyroid incidentalomas.

Fluorine-18-fluorodeoxyglucose PET/CT for the evaluation of suspected recurrent uterine leiomyosarcomas.

BACKGROUND: Uterine leiomyosarcomas are rare and aggressive malignancies of the uterine corpus with high recurrence rates and poor prognoses. The current recommendation for detection of recurrent uterine leiomyosarcoma involves periodic physical examination and conventional imaging such as CT or MRI. The role of fluorine-18-fluorodeoxyglucose positron emission tomography with integrated computed tomography (FDG-PET/CT) in the detection of recurrent uterine leiomyosarcomas is not yet established. PURPOSE: To evaluate the use of FDG-PET/CT as a single integrated modality for the evaluation of suspected recurrent uterine leiomyosarcomas. MATERIAL AND METHODS: A retrospective study was performed on patients who underwent FDG-PET/CT scans for suspected recurrent uterine leiomyosarcoma. Only patients with follow-up data were included in the study. FDG-PET/CT was evaluated as a single integrated imaging modality. A positive lesion on FDG-PET/CT was defined as a focal abnormality detected on either the PET or CT components, or both. RESULTS: Sixteen consecutive patients over 5 years underwent FDG-PET/CT for suspected recurrent uterine leiomyosarcoma. Five patients were excluded due to incomplete follow-up data. The remaining 11 patients were aged 36-58 years (mean age 48). FDG-PET/CT had a sensitivity of 100% (95% CI 63-100) and specificity of 100% (95% CI 20-100) for the detection of recurrent uterine leiomyosarcomas. Sites of metastases include lungs, peritoneum, liver, pancreas and breast, of which lungs and peritoneum were the most common. Two (18%) patients had discordant findings: FDG-PET negative metastatic nodules in the breast and lung detected on the CT component. The maximum standardized uptake value (SUVmax) of metastatic lesions ranged from 2.0 to 16.0 (mean 7.6). CONCLUSION: FDG-PET/CT as a single integrated modality may be a useful for the evaluation of suspected recurrent uterine leiomyosarcomas. FDG-PET negative discordant nodules detected on the CT component may represent metastases and should be followed up closely.

Short term clinical and echocardiography outcomes of pericardiectomy in constrictive pericarditis.

Introduction: Tuberculous pericarditis continues to be a leading cause of chronic constrictive pericarditis (CCP) in developing countries. Echocardiography plays a key role in the assessment and diagnosis. Methods: Twelve patients who underwent pericardiectomy for CCP in last 18 months of the study period were subjected to clinical and New York Heart Association (NYHA) functional class assessment along with comprehensive echocardiographic evaluation. The data were compared with their preprocedural status. Results: Significant reduction was noted in the incidence of inferior vena cava (IVC) congestion(P < 0.001) and mean left atrial (LA) size from 43.75 ± 4.43 mm to 31.58 ± 3.03 mm (P < 0.001), post pericardiectomy.Respiratory variation of 34.17 ± 8.76 % in the mitral E velocity was significantly reduced to 17 ± 3.69 % (P < 0.001) after surgery. Similarly, respiratory variation in tricuspid E velocities showed significant reduction from 62.17 ± 13.16 % to 32.58 ± 4.7 % (P < 0.001).Prior to pericardiectomy, medial e' and lateral e' mitral annular velocities was 15.5±1.24 cm/sec and13.08 ± 1.08 cm/sec, respectively. Following surgery, the medial e' and lateral e' was 12.5±1.17 cm/sec(P = 0.001) and 15.42±1.83 (P = 0.004), respectively. Conclusion: Echocardiography provides useful insight in pericardial constriction hemodynamics and worthwhile effects of pericardiectomy.

Thematic planning: the role of the International Atomic Energy Agency in promoting education, medical research, and technology transfer among nuclear medicine communities of developing countries.

One of the major mechanisms of implementing the International Atomic Energy Agency's (IAEA) programs in nuclear medicine has been through coordinated research projects (CRPs). In recent years, the IAEA has initiated a new type of CRP, called Doctoral CRP, in an attempt to further improve the effectiveness of its programs. The structure of the Doctoral CRP has been built on the structure of the existing CRP concept, but with a broader "thematic" approach. The word "thematic" indicates that these CRPs should both have a fairly broad scope and be designed so that their outcome, in terms of practical applications, might readily fit into the selected nuclear applications that are offered to Member States under the IAEA's mechanism for thematic planning. The Nuclear Medicine Section of IAEA's Division of Human Health initiated the first Doctoral CRP of IAEA in the year 2000, entitled, "Management of Liver Cancer Using Radionuclide Methods with Special Emphasis on Trans-Arterial Radio-conjugate Therapy and Internal Dosimetry." Since then, the CRP has accomplished several milestones, including development of a new therapeutic radiopharmaceutical ((188)Re lipiodol) and successfully carrying out Phase I and Phase II clinical trials on patients using the new therapeutic radiopharmaceutical.

A report on the implementation aspects of the International Atomic Energy Agency's first doctoral coordinated research project, "Management of liver cancer using radionuclide methods with special emphasis on trans-arterial radio-conjugate therapy and internal dosimetry".

Liver cancer is one of the most dreaded cancers, and it is highly prevalent in the developing countries, where the resources are extremely scarce to deal with this disease using the current commercially available and expensive therapeutic radiopharmaceuticals. The International Atomic Energy Agency (IAEA), in pursuit of its mandate to promote the application of nuclear technology in the health care in its Member States, has developed and clinically evaluated a new and cost-effective therapeutic radio-conjugate, rhenium-188 ((188)Re)-lipiodol for the treatment of hepatocellular carcinoma through its first Doctoral Coordinated Research Project. The ready availability of no-carrier-added (188)Re from the tungsten-188/(188)Re generator represents a potentially important source of a therapeutic radioisotope for a broad range of therapeutic applications in nuclear medicine. The alumina-based tungsten-188/(188)Re generator system comes with reasonable cost and exhibits attractive therapeutic properties, excellent performance and very long useful shelf-life. Because of the long shelf-life of several months, the use of this generator offers a unique opportunity for the cost-effective and routine availability of a versatile therapeutic radioisotope on an on-demand basis. Further, using its extensive global network and outreach, the IAEA has also transferred the technology of the in-house preparation and use of (188)Re-labeled lipiodol to many institutions around the world, which can now prepare (188)Re-labeled lipiodol in their own radiopharmacy laboratories and treat patients. This effort of the IAEA in trying to address some of the challenges of liver cancer therapy in developing countries has been and truly a global venture with involvement and contributions from several organizations, institutions and numerous individuals. This article discusses some of the implementation aspects of this very important activity of the Agency.

International Atomic Energy Agency-sponsored multination study of intra-arterial rhenium-188-labeled lipiodol in the treatment of inoperable hepatocellular carcinoma: results with special emphasis on prognostic value of dosimetric study.

A multicenter study was sponsored by the International Atomic Energy Agency (IAEA) to assess the safety and efficacy of transarterial rhenium-188 ((188)Re) HDD lipiodol (radioconjugate to lipiodol using an HDD kit) in the treatment of unresectable hepatocellular carcinoma. During 5 years, 185 patients received at least 1 treatment of radioconjugate, and 51 were retreated. The level of radioconjugate administered was based on radiation-absorbed dose to critical normal organs, calculated after a "scout" dose of radioconjugate. The total injected activity, including the scout dose during the first treatment, ranged from 21 to 364 mCi (mean, 108 mCi/4 GBq). Immediate and late side-effects were minimal. Tumor size could be evaluated in 88 patients. Among these patients, the objective response rate was 25%; stable disease was observed in 53% and tumor progression in 22%. With a median follow-up of 455 days, the estimated 12- and 24-month overall survival was 46% and 23%. This multicenter study shows that (188)Re lipiodol is a safe and cost-effective method to treat primary hepatocellular carcinoma via the transarterial route and requires further evaluation by treatment of greater numbers of patients.

Surgical challenge in situs inversus with dextrocardia and Lutembacher syndrome.

Situs inversus with dextrocardia and Lutembacher syndrome is a rare cardiac anomaly. It is associated with other complex cardiac anomalies and anatomical defects. A 30-year-old woman with this condition underwent mitral valve replacement and closure of a secundum atrial septal defect. We describe the surgical approach, position of the surgeon, and bicaval cannulation technique for this anatomical aberration.

Intra-arterial rhenium-188 lipiodol in the treatment of inoperable hepatocellular carcinoma: results of an IAEA-sponsored multination study.

PURPOSE: Intra-arterial injections (IAI) of 131I-lipiodol is effective in treating hepatocellular carcinoma patients, but is expensive and requires a 7-day hospitalization in a radioprotection room. 188Re is inexpensive, requires no patient isolation, and can be used with lipiodol. METHODS AND MATERIALS: This International Atomic Energy Agency-sponsored phase II trial aimed to assess the safety and the efficacy of a radioconjugate 188Re + lipiodol (188Re-Lip) in a large cohort of hepatocellular carcinoma patients from developing countries. A scout dose is used to determine the maximal tolerated dose (lungs <12 Gy, normal liver <30 Gy, bone marrow <1.5 Gy) and then the delivery of the calculated activity. Efficacy was assessed using response evaluation criteria in solid tumor (RECIST) and alpha-feto-protein (alpha FP) levels and severe adverse events were graded using the Common Toxicity Criteria of the National Cancer Institute scale v2.0. RESULTS: The trial included 185 patients from eight countries. The procedure was feasible in all participating centers. One treatment was given to 134 patients; 42, 8, and 1 received two, three, and four injections, respectively. The injected activity during the first treatment was 100 mCi. Tolerance was excellent. We observed three complete responses and 19 partial responses (22% of evaluable patients, 95% confidence interval 16-35%); 1- and 2-year survivals were 46% and 23%. Some factors affected survival: country of origin, existence of a cirrhosis, Cancer of the Liver Italian Program score, tumor dose, absence of progression, and posttreatment decrease in alpha FP level. CONCLUSIONS: IAI of 188Re-Lip in developing countries is feasible, safe, cost-effective, and deserves a phase III trial.

Radioiodine Remnant Ablation: A Critical Review.

Radioiodine remnant ablation (RRA) is considered a safe and effective method for eliminating residual thyroid tissue, as well as microscopic disease if at all present in thyroid bed following thyroidectomy. The rationale of RRA is that in the absence of thyroid tissue, serum thyroglobulin (Tg) measurement can be used as an excellent tumor marker. Other considerations are like the presence of significant remnant thyroid tissue makes detection and treatment of nodal or distant metastases difficult. Rarely, microscopic disease in the thyroid bed if not ablated, in the future, could be a source of anaplastic transformation. On the other hand, microscopic tumor emboli in distant sites could be the cause of distant metastasis too. The ablation of remnant tissue would in all probability eliminate these theoretical risks. It may be noted that all these are unproven contentious issues except postablation serum Tg estimation that could be a good tumor marker for detecting early biochemical recurrence in long-term follow-up strategy. Radioactive iodine is administered as a form of "adjuvant therapy" for remnant ablation. There have been several reports with regard to the administered dose for remnant ablation. The first report of a prospective randomized clinical trial was published from India by a prospective randomized study conducted at the All India Institute of Medical Sciences, New Delhi in the year 1996. The study reported that increasing the empirical (131)I initial dose to more than 50 mCi results in plateauing of the dose-response curve and thus, conventional high-dose remnant ablation needs critical evaluation. Recently, two important studies were published: One from French group and the other from UK on a similar line. Interestingly, all three studies conducted in three different geographical regions of the world showed exactly similar conclusion. The new era of low-dose remnant ablation has taken a firm scientific footing across the continents.

Spontaneous pneumomediastinum: A complication of swine flu.

The occurrence of spontaneous pneumomediastinum in swine flu, or H1N1 influenza A infection, is a rare phenomenon and only few cases have been reported in children. We describe a case of spontaneous pneumomediastinum in adult infected with swine flu.

Diagnostic value of 99mTc-methylene diphosphonate and 99mTc-pentavalent DMSA compared with 99mTc-sestamibi for palpable breast lesions.

UNLABELLED: Different radiopharmaceuticals have been used to detect breast cancer. Among them, sestamibi has been extensively studied and has come to have a well-recognized role in the evaluation of palpable breast lesions. The goal of this study was to compare the diagnostic value of 99mTc-labeled compounds, such as methylene diphosphonate (MDP) and pentavalent dimercaptosuccinic acid (DMSA-V), with sestamibi for palpable breast lesions, in the scope of a multicenter trial sponsored by the International Atomic Energy Agency. METHODS: Patients from 7 countries were included: 47 women (mean age, 54 +/- 13 y) examined with MDP and sestamibi and 111 women (mean age, 55 +/- 12 y) examined with DMSA-V and sestamibi. Cancer was diagnosed in 41 of 49 lesions from the MDP group and in 78 of 113 lesions from the DMSA-V group. Axillary lymph node involvement was observed in 18 of 30 patients from the first group and in 27 of 53 patients from the second group. Prone scintimammography was performed using a dose of 740 MBq of each tracer, and diagnostic values were calculated from a masked interpretation of scans. RESULTS: In the first group, the sensitivity for sestamibi and MDP studies was 82.9% and 65.9%, respectively, with a specificity of 87.5% and 50%, respectively. In the second group, the sensitivity for sestamibi and DMSA-V studies was 87.2% and 65.4%, respectively, with a specificity of 77.1% and 74.3%, respectively. Regarding axillary involvement, the sensitivity was 33.3% for sestamibi in both groups, whereas the values for MDP and DMSA-V were 16.7% and 7.4%, respectively. In contrast, the specificity for sestamibi was 83.3% and 92.3% for the first and second groups, respectively, and the specificity for MDP and DMSA-V was 91.7% and 100%, respectively. CONCLUSION: Sestamibi is the most adequate alternative among the mentioned 99mTc-labeled radiopharmaceuticals for the evaluation of palpable breast lesions.

Incidental detection of clinically nondiagnosed inguinal hernia in (131)I whole-body scan.

I whole-body bone scan was performed for an adult male patient after postradioactive iodine ablation of thyroid carcinoma. Besides the small thyroid remnants in the neck region, an incidental detection of left inguinal hernia was made in the scan, which was later confirmed by clinical examination. Despite the large size of the hernia, the patient was unaware of the condition. It can be concluded that, similar to other imaging procedures, incidental detection of unrelated clinical problems is possible in I scan also, and such early diagnosis prevents further complications that the patient may develop in the future.

Controversies about radioactive iodine-131 remnant ablation in low risk thyroid cancers: are we near a consensus?

Well differentiated thyroid cancers (WDTC), including papillary (80%) and follicular (10%) types, are the most common endocrine cancers globally. Over the last few decades most the diagnosed cases have fallen into low risk categories. Radioactive iodine-131 (RAI) has an established role in reducing recurrence and improving the survival in high risk patients. In patients with primary tumor size <1 cm, RAI is not recommended by many thyroid societies. However, low risk WDTC has been an arena of major controversies, most importantly the role and dose of adjuvant RAI for remnant ablation to minimize chances of recurrence and improving survival. This review is an attempt to update readers about the previous and existing practice based on results of non- randomized trials and evolving trends fueled by recently published randomized studies.

Potential requirement of positron emission tomography apparatuses in Asia and latin america including Mexico.

The number of positron emission tomography (PET) machines has been increasing in regions of East-, Southeast-, and South-Asia as well as in Latin America including Mexico. This study was performed to assess the potential requirement of PET machines in 19 countries which already use PET in the aforementioned regions. Data on the number of PET machines and internationally available characteristics of the restrictive countries such as the land area, the total population, the gross national income (GNI), and the average life span of inhabitants were obtained from IAEA, UN, WB, and WHO. Correlation between the number of PET machines and the characteristics of each country was evaluated. The potentially required number of PET machines, which was obtained by adjusting the number of PET machines with statistically significant, correlative characteristics of each country, standardized on the state of Japan, were compared. The number of PET machines could be significantly correlated to the GNI of a country and the average life span of its inhabitants (P < 0.05). Based on Japan, most of the countries in the regions would require considerably more PET machines. With installation of the potentially required number of PET machines in each of the countries, the number of PET machine per 10(6) population would increase by 1.1- to 12-fold, in comparison with the current situation. With regards to the potentially required number of PET machines, most of the countries in these regions may require a considerable increase of PET machines. Nevertheless, some countries in the Asia seem to require outside assistance such as international support in order to introduce PET and enhance the efficacy of their health services.

Extraosseous uptake of technetium-99m methylene diphosphonate by an acute territorial cerebral infarct in a classical biodistribution pattern.

Technetium-99m methylene diphosphonate scintigraphy is usually performed to assess bone lesions, especially skeletal metastases in patients with a history of malignancy. However, it is important to recognize some specific conditions with a unique pattern of tracer uptake, especially in extraosseous locations as they are not related to primary neoplasm or metastases. Diagnosing such unusual presentation is essential as it significantly influences the clinical management. This case report describes an unusual presentation detected in a bone scan of an elderly female patient, who was a treated case of breast cancer and was referred for a bone scan to rule out bone metastases. Incidentally, a large acute territorial cerebral infarct was diagnosed, which was later confirmed by magnetic resonance imaging on diffusion-weighted images. Diagnosis of the typical presentation and timely management saved the patient life.

Unusual presentation of extraosseous metastases on bone scintigraphy.

Osteosarcoma metastases frequently occur in the lungs or the skeleton. Bone scans play an important role in disease staging by identifying other skip areas of skeletal involvement as well as extraosseous metastases. We report a case of aggressive osteosarcoma, with bone metastases and extraosseous areas of involvement in the lungs, distant lymph nodes, and peritoneal and subcutaneous metastasis seen in a preoperative Tc-99m methylene diphosphonate bone scan. These findings were confirmed with histology and correlative cross-sectional imaging.

Differentiating suspected nasopharyngeal infection from carcinoma using dual-tracer and multiple time-point technetium-99m sestamibi and white blood cell SPECT/CT imaging.

The role of molecular and functional imaging lies in its capability to more accurately define and characterize pathologies, with a host of varied radiotracers and techniques being available to the clinician for use. We present a case in which dual-tracer and multiple time-point single photon emission computed tomography/computed tomography imaging using technetium-99m sestamibi and white blood cell radiotracers was used to characterize an indeterminate base of skull lesion.