Hydrocephalus-related symptoms that worsen after shunt placement may indicate a malfunctioning or obstructed shunt. The assessment of shunt patency and site of obstruction is important for planning of treatment. The radionuclide cerebrospinal fluid (CSF) shunt study provides a simple, effective, and low-radiation-dose method of assessing CSF shunt patency. The radionuclide CSF shuntography is a useful tool in the management of patients presenting with shunt-related problems not elucidated by conventional radiological examination. This article described the imaging technique of ventriculoperitoneal (VP) shunt and lumbar puncture (LP) shunt. The normal finding, abnormal finding of completed obstruction and partial obstruction is present by our cases experience. The radiopharmaceutical (Tc-99m diethylenetriaminepentaacetic acid) was injected via the reservoir for VP shunt and via lumbar puncture needle in subarachnoid space for LP shunt, then serial image in the head and abdominal area. The normal function of VP and LP shunt usually rapid spillage of the radioactivity in the abdominal cavity diffusely. The patent proximal tube VP shunt demonstrates ventricular reflux. The early image of patent LP shunt reveals no activity in the ventricular system contrast to distal LP shunt reveals early reflux of activity in the ventricular system. The completed distal VP and LP shunt obstruction show absence of tracer in the peritoneal area or markedly delayed appearance of abdominal activity. The partial distal VP and LP shunt obstruction recognized by slow transit or accumulation of tracer at the distal end or focal tracer in the peritoneal cavity near the tip of distal shunt. The images of the normal and abnormal CSF shunt as describe before are present in the full paper. Radionuclide CSF shuntography is a reliable and simple procedure for assessment shunt patency.

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Knowledge of the physiological testicular accumulation of ¹⁸ F-fluoro-2-deoxyglucose (FDG) is essential in order to discriminate between normal and pathological findings. In this study, the ¹⁸ F-FDG-uptake in healthy testes of young men was assessed using positron emission tomography/computed tomography (PET/CT)-scans. A total of 40 testes of 20 men with a mean age of 26.5 ± 3.9 years were evaluated. ¹⁸ F-FDG-uptake was expressed as the standardized uptake value (SUV). Testicular volume was measured on CT and PET. All scans were assessed by three researchers, one of whom assessed every scan twice. Laterality indices and inter- and intra-observer variation were evaluated. Correlation between the SUV _max and SUV _peak , between SUV _mean and SUV _peak and between age and SUV _peak were assessed. Testes showed an average SUV _max of 3.42 ± 0.61 _, SUV _peak of 3.06 ± 0.54 and SUV _mean of 2.44 ± 0.44. The average testicular volume on CT was 23.0 ± 6.4 ml, whereas on PET it was 18.0 ± 5.1 ml. Laterality indices were calculated of 0.077 ± 0.065 (SUV _max ), 0.074 ± 0.066 (SUV _peak ), 0.072 ± 0.063 (SUV _mean ), 0.245 ± 0.259 (CT), and 0.200 ± 0.188 (PET), respectively. Inter- and intra-observer reliability were found to be perfect for the SUVs (intraclass correlation coefficient [ICC] 0.992-1.0), but poor for testicular volumes (ICC 0.854-0.902). Testicular ¹⁸ F-FDG uptake in young men can be measured accurately on PET/CT and shows high symmetry. Consequently, ¹⁸ F-FDG PET/CT has the potential to become a useful instrument in the evaluation of the functioning of the individual testis.

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Objective: To update the prognostic value of scan strategy with pharmacological stress agent in chest pain (CP) patients presenting with normal electrocardiography (ECG) and troponin. Methods: Two consecutive nonrandomized series of patients with CP and negative first-line workup inclusive of serial ECG, serial troponin, and echocardiography underwent myocardial perfusion imaging single photon emission computed tomography (SPECT) in the emergency department. Of 170 patients enrolled, 52 patients underwent dipyridamole-SPECT and 118 adenosine-SPECT. Patients with perfusion defects underwent angiography, whereas the remaining patients were discharged and followed-up. Primary endpoint was the composite of nonfatal myocardial infarction, unstable angina, revascularization, and cardiovascular death at follow-up or the presence of coronary stenosis > 50% at angiography. Results: At multivariate analysis, the presence of perfusion defects or hypertension was independent predictor of the primary endpoint. Sensitivity and negative predictive value were higher in patients subjected to adenosine-SPECT (95% and 99%, respectively) versus dipyridamole-SPECT (56% and 89%; yield 70% and 11%, respectively; P < 0.03). Of note, sensitivity, negative, and positive predictive values were high in patients with hypertension (100%, 93%, and 60%, respectively) or nonischemic echocardiography alterations (100%, 100%, and 100%, respectively). Conclusions: In CP patients, presenting with normal ECG and troponin, adenosine-SPECT adds incremental prognostic values to dipyridamole-SPECT. Costly scan strategy is more appropriate and avoids unnecessary angiograms in patients with hypertension or nonischemic echocardiography alterations.

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There is a growing health burden in developing countries due to recent trends of increasing incidence of neurodegenerative diseases. To reduce the healthcare cost and effective management of dementia illness, early diagnosis, accurate differentiation and their progression assessment is becoming crucially important. We are utilizing ^99m Tc-d, l-hexamethyl propyleneamine oxime (HMPAO) brain perfusion single photon emission computed tomography (SPECT) to characterize dementia on the basis of perfusion patterns and observed significant improvement in their management. Eleven patients (median age of 60 years range of 53-83 years) with clinical suspicion of dementia underwent ^99m Tc-HMPAO brain perfusion SPECT. SPECT-computed tomography acquisition done, data are reconstructed, reviewed in three view and further processed in "neurogam" to get voxel based analysis and the comparison with age based normal database and surface mapping. Final diagnosis was done with clinical correlation. Four patients are diagnosed as Alzheimer's disease, two as frontotemporal dementia, one as dementia of Lewy bodies, two as vascular dementia and two as pseudodementia. All imaging findings are well-correlated with clinical background. Brain perfusion SPECT with HMPAO was very helpful to us in characterizing the patients of dementia by its perfusion pattern.

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Our patient is a female who was first diagnosed with breast cancer at the age of 23. A follow-up fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) at age 44 revealed diffuse high FDG uptake in an enlarged thyroid gland. Fine-needle aspiration (FNA) of the thyroid mass revealed estrogen receptor/progesterone receptor negative, human epidermal growth factor receptor 2+ breast cancer. To the best of our knowledge, this is the first case to report breast cancer metastasis to the thyroid in a diffuse pattern on FDG-PET/CT. Bilateral diffuse uptake of FDG in thyroid is the most commonly associated with benign conditions. However, FNA biopsies need to be done to rule out metastatic disease in thyroid lesions with diffuse high FDG uptake, especially for patients with history of cancer.

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We are presenting a 59 years old man with locally advanced recto-sigmoid colon cancer; complaining of left flank pain and bone scan was done to rule out bone metastases. Findings in bone scan were suggesting left renal obstruction, but further SPECT/CT imaging to localize the uptake revealed a perinephric collection likely due to leak from the left ureter close to tumor site.

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Regadenoson is a widely used and well-tolerated vasodilator agent for pharmacologic stress myocardial perfusing imaging. In patients at higher risk of adverse reactions such as those with end stage renal disease, it can be reversed with early administration of aminophylline. However, little is known about late administration of aminophylline. This case report describes the efficacy of late aminophylline use in patients with end stage renal disease. Possible explanations for the prolonged pharmacodynamic effect of regadenoson in this group are discussed.

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We present a case of a 60-year-old white male with a history of papillary renal cell carcinoma (PRCC) status postpartial nepherectomy. He was followed-up annually with abdominal computed tomography (CT) scans to monitor for tumor recurrence. A solitary metastatic bony lesion was detected by CT 4 years after partial nephrectomy and it was confirmed by NaF-positron emission tomography (PET)/CT and magnetic resonance imaging. He underwent external beam radiation therapy (XRT) for solitary metastasis to L1 vertebra. The L1 lesion was treated with XRT, which exhibited no fluorodeoxyglucose activity after the treatment. This is the first case report to mention the use of NaF-18-PET/CT in the detection of bone metastasis from PRCC. Our case once again emphasizes the usefulness of NaF-18-PET/CT in RCC follow-up.

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Equilibrium radionuclide ventriculography is an established modality to assess the left ventricular (LV) systolic function in several clinical situations. Diastolic parameters can also be extracted from this investigation. The aim of our study is to assess the diastolic function of the left ventricle in cases of idiopathic dilated cardiomyopathy (IDCM) and ischemic cardiomyopathy, where systolic dysfunction has been considered of prime pathologic significance. We conducted a retrospective analysis of 89 patients who had undergone radionuclide ventriculography at our department with established diagnosis of IDCM in 59 patients and ischemic cardiomyopathy in remaining 30 patients. Peak filling rate (PFR) was assessed. The PFR was significantly lower in both patients with IDCM (median = 1.61 end diastolic volumes [EDV]/s) and ischemic cardiomyopathy (median = 2.005 EDV/s). 33% of the patients with ischemic cardiomyopathy and ejection fraction (EF) >45% had diastolic dysfunction while 25% of patients with IDCM and EF >45% had low PFR. Diastolic dysfunction can coexist in patients with dilated cardiomyopathy and even in patients with preserved LV EF. Routine evaluation of diastolic function in patients with heart failure can help in elucidation of pathogenesis and management of patients.

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To determine the prevalence of incidental finding of unknown cerebral metastases and explore the clinical impact of detecting unknown brain metastases among individuals underwent whole body fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) with brain included in field of view. A retrospective review of 1876 patients who underwent whole body PET/CT examination in our clinical PET center for oncological evaluation from January 2009 to September 2009 was performed. The total number and prevalence of unknown brain metastases detected by PET/CT were calculated. Patients diagnosed with cerebral metastases by PET/CT were further analyzed via the electronic patient record system for relevant clinical and radiological findings. Positive predictive value of PET/CT for the diagnosis of cerebral metastases was calculated with reference to contrast enhanced magnetic resonance imaging (MRI) or contrast enhanced CT. Of the 1876 subjects, 71 patients (3.8%) were diagnosed with cerebral metastases by PET/CT. 31 patients were already diagnosed with brain metastases before PET/CT. Among the 40 patients with unknown brain metastasis, 24 (60.0%) underwent either MRI (n = 5) or CT (n = 19) after PET/CT, of which 17 patients were confirmed with cerebral metastases. The true positive rate was 70.8% (17/24), while the false positive rate of PET/CT was 29.2% (7/24). Nearly 94.1% (16/17) patients with confirmed cerebral metastases on MRI or CT had subsequent change in management. Among the remaining 16 patients with positive findings of cerebral metastases without further radiological correlation, 43.8% (7/16) patients had change in management after PET/CT. A total of 57.5% (23/40) patients had change in management after PET/CT. The point prevalence of detecting unknown cerebral metastases by PET/CT was 2.1% (40/1876). 94.1% patients with newly diagnosed brain metastases confirmed with either MRI or CT received immediate treatment for cerebral metastasis in this retrospective study. PET/CT demonstrated significant clinical impact by identifying cerebral lesions with mass effect and hence that timely treatment was offered.

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To assess the prognostic value of maximum standardized uptake value (maxSUV) of the primary tumor (maxSUV _pt ), maxSUV of whole-body tumors (maxSUV _wb ) and sum of maximum standardized uptake value (sumaxSUV) measured by the sum of maxSUVs of the primary tumor, metastatic lymph nodes, and metastatic lesions per each organ on fluoro-D-glucose-positron emission tomography/computed tomography in advanced non-small cell lung cancer (NSCLC). Eighty-three patients (49 male, 34 female) with advanced NSCLC were enrolled. Seventeen patients had Stage IIIA, 21 Stage IIIB, and 45 Stage IV. maxSUV _pt , maxSUV _wb , sumaxSUV, age, gender, tumor-cell type, T stage, N stage, overall stage, primary tumor size, and specific treatment were analyzed for correlation with overall survival. Median follow-up duration was 13 months. Fifty patients were dead during a median follow-up time of 11 months and 33 patients were alive with a median time of 15 months. Univariate analysis revealed that overall survival was significantly correlated with sumaxSUV (≥35 vs. <35, P = 0.004), T stage (T4 vs. T1-T3, P = 0.025), overall stage (IV vs. III, P = 0.002), gender (male vs. female, P = 0.029) and specific treatment (no vs. yes, P = 0.011). maxSUV _pt and maxSUV _wb were not correlated with overall survival with P value of 0.139 and 0.168, respectively. Multivariate analysis identified sumaxSUV, T stage, gender, and specific treatment as independent prognostic indicators. Patients with a sumaxSUV of ≥35 were 1.921 times more likely to die than those with a sumaxSUV of < 35 (P = 0.047). Median survival time was 14 months for patients with sumaxSUV ≥ 35 compared with 20 months for those with sumaxSUV < 35. In patients with metastatic NSCLC, sumaxSUV with cut-off of 35 was much more significant for survival prognosis (P = 0.021). sumaxSUV is a new prognostic measure, independent of tumor stage, gender, and specific treatment in advanced NSCLC. sumaxSUV may be better than maxSUV _pt and maxSUV _wb in prediction of survival. A large prospective cohort study is necessary to validate these results.

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¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has become increasingly relevant in the staging of head and neck cancers, but its prognostic value is controversial. The objective of this study was to evaluate different PET/CT parameters for their ability to predict response to therapy and survival in patients treated for head and neck cancer. A total of 28 consecutive patients with a variety of newly diagnosed head and neck cancers underwent PET/CT scanning at our institution before initiating definitive radiation therapy. All underwent a posttreatment PET/CT to gauge tumor response. Pretreatment PET/CT parameters calculated include the standardized uptake value (SUV) and the anatomical biological value (ABV), which is the product of SUV and greatest tumor diameter. Maximum and mean values were studied for both SUV and ABV, and correlated with response rate and survival. The mean pretreatment tumor ABV _max decreased from 35.5 to 7.9 (P = 0.0001). Of the parameters tested, only pretreatment ABV _max was significantly different among those patients with a complete response (CR) and incomplete response (22.8 vs. 65, respectively, P = 0.021). This difference was maximized at a cut-off ABV _max of 30 and those patients with ABV _max < 30 were significantly more likely to have a CR compared to those with ABV _max of ≥ 30 (93.8% vs. 50%, respectively, P = 0.023). The 5-year overall survival was 80% compared to 36%, respectively, (P = 0.028). Multivariate analysis confirmed that ABV _max was an independent prognostic factor. Our data supports the use of PET/CT, and specifically ABV _max , as a prognostic factor in head and neck cancer. Patients who have an ABV _max ≥ 30 were more likely to have a poor outcome with chemoradiation alone, and a more aggressive trimodality approach may be indicated in these patients.

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Maximum standardized uptake value (SUVmax) from fluorodeoxyglucose (FDG) positron emission tomography (PET) scans is a semi quantitative measure that is increasingly used in the clinical practice for diagnostic and therapeutic response assessment purposes. Technological advances such as the implementation of the point spread function (PSF) in the reconstruction algorithm have led to higher signal to noise ratio and increased spatial resolution. The impact on SUVmax measurements has not been studied in clinical setting. We studied the impact of PSF on SUVmax in 30 consecutive lung cancer patients. SUVmax values were measured on PET-computed tomography (CT) scans reconstructed iteratively with and without PSF (respectively high-definition [HD] and non-HD). HD SUVmax values were significantly higher than non-HD SUVmax. There was excellent correlation between HD and non-HD values. Details of reconstruction and PSF implementation in particular have important consequences on SUV values. Nuclear Medicine physicians and radiologists should be aware of the reconstruction parameters of PET-CT scans when they report or rely on SUV measurements.

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