Left ventricular diastolic parameters in dilated cardiomypoathy: are we missing out on something?

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.

Fluoro-deoxy-glucose positron emission tomography/computed tomography in lymphoma: A pictorial essay.

F-18 fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has emerged as a powerful imaging modality in the field of oncology. F-18 FDG PET/CT is now an established tool in the management of lymphoma. This has been shown to be useful in staging, detection of bone marrow involvement (BMI), early response assessment and end of therapy response assessment in lymphoma. Interpretation of F-18 FDG PET/CT in lymphoma is carried out by various qualitative response assessment criteria. London criteria are used for interpretation of interim PET/CT and International Harmonization Project (IHP) criteria are used to interpret PET/CT done after the end of chemotherapy. Quantitative analysis is also found to be useful in assessment of response early after two cycles of chemotherapy in patients with diffuse large B cell lymphoma (DLBCL). This pictorial essay provides few images describing the FDG avidity of lymphoma, patterns of bone marrow uptake and their relevance in predicting BMI, role of staging PET/CT, quantitative analysis in response assessment, example images of response according to London criteria and IHP criteria. Few pitfalls in imaging of lymphoma with PET/CT are also discussed in the images legend.

Role of 18F-FDG PET/CT in identifying distant metastatic disease missed by conventional imaging in patients with locally advanced breast cancer.

OBJECTIVES: This study was conducted to evaluate the role of (18)F-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (CT) in identifying missed distant metastases in patients with locally advanced breast cancer (LABC) who were assessed by conventional imaging methods. MATERIALS AND METHODS: Forty-three consecutive patients with histopathologically proven LABC with negative conventional imaging results for distant metastases were included in the study. All of them underwent (18)F-FDG PET/CT within a week after conventional imaging. RESULTS: (18)F-FDG PET/CT findings suggestive of distant metastases were noted in 11/43 patients, and 10 of them were confirmed to have true-positive distant metastatic disease on clinical follow-up of 6 months. None of the patients with negative (18)F-FDG PET/CT for distant metastases developed distant metastases during the follow-up. (18)F-FDG PET/CT had a sensitivity, specificity, positive predictive value, and negative predictive value of 100, 96.8, 91, and 100%, respectively, for identifying distant metastases missed by conventional imaging. In addition, (18)F-FDG PET/CT suggested previously unknown lymph nodal metastases in 16/43 (37%) patients. Change in stage was noticed in 17/43 (39.5%) patients. CONCLUSION: (18)F-FDG PET/CT is a sensitive and specific imaging modality for identifying distant metastases in patients with LABC missed by conventional imaging. In addition, it detects unknown lymph nodal metastases in a significant proportion of patients and hence can be used routinely in staging of patients with LABC.

F-18 FDG-PET/CT in evaluation of patients with fever of unknown origin.

OBJECTIVES: This study was carried out to evaluate the diagnostic utility of FDG-PET/CT in patients with fever of unknown origin (FUO). METHODS: Medical records of 103 patients who underwent FDG-PET/CT and anatomic imaging as a part of FUO workup were analyzed. Final diagnosis of the cause of FUO was reached based on serologic assays, cultures, biopsy, surgery or 6 months of clinical follow-up. RESULTS: The definite cause of fever was established in 69/103 patients. Abnormal FDG uptake was found in 63/103 patients and contributed to the final diagnosis (TP) in 62 patients (98.48 %). Of the remaining 40 patients with negative PET/CT, the final definite cause of fever (FN) could be determined only in seven patients (17.5 %). PET/CT had a sensitivity, specificity, positive predictive value and negative predictive value of 90, 97, 98.4 and 82.5 % compared to 43.5, 67.6, 73.2 and 37.1 %, respectively, for anatomic imaging. FDG-PET/CT had a higher accuracy (92.2 vs. 51.5 %; p = 0.003) compared to anatomic imaging for suggesting a cause of FUO. CONCLUSIONS: PET/CT showed high sensitivity and specificity in suggesting a definite diagnosis in the evaluation of FUO.

Low positive yield from routine inclusion of the brain in whole-body 18F-FDG PET/CT imaging for noncerebral malignancies: results from a large population study.

OBJECTIVE: This retrospective study was conducted to assess the incremental value, if any, of including the brain in whole-body fluorine-18 fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) studies in patients with extracalvarial primary malignancies. METHODS: The scan data of 5110 F-FDG PET/CT studies conducted from March 2009 to December 2011 were reviewed. RESULTS: Abnormal brain lesions were detected in 76/5110 patients who had undergone F-FDG PET/CT studies. Among them, 16 patients had lesions with F-FDG uptake less than that of the surrounding background and 54 had lesions with increased F-FDG uptake. Six patients had neither increased nor decreased tracer uptake in their brain lesions (identified on the CT component of the study). In the first group of patients, infarct was seen in four patients, treated brain metastases were seen in eight (five surgical and three through external beam radiotherapy), and untreated metastases were seen in four patients. In the 54 patients with increased uptake, metastatic lesions were identified in 51 and central nervous system involvement by systemic lymphoma in three. The third group showed metastases in four patients and central nervous system involvement by systemic lymphoma in one; one patient was lost to follow-up without a final diagnosis. Out of 63 patients with untreated cerebral metastases detected on the F-FDG PET/CT study, cerebral metastases were unknown before F-FDG PET/CT in 40 patients. Of these 40 patients, the brain was the only site of metastatic involvement in eight patients. CONCLUSION: Inclusion of the brain routinely in whole-body F-FDG PET/CT studies detected previously unknown metastases in only 0.7% (40/5110) of studies, with negligible impact (0.15%) on staging.

Intense FDG activity in a case of xanthogranulomatous cholecystitis without elevated fluorothymidine activity.

F-FDG PET/CT is a useful imaging modality to detect malignant gall bladder lesions. We present an image of a patient with a gall bladder mass that was found to be FDG avid but negative on F-fluorothymidine PET/CT imaging. This was later confirmed to be a case of xanthogranulomatous cholecystitis.

Comparison of various criteria in interpreting end of therapy F-18 labeled fluorodeoxyglucose positron emission tomography/computed tomography in patients with aggressive non-Hodgkin lymphoma.

Various interpretation criteria exist to assess end of therapy F-18 labeled fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in lymphoma. This study was carried out to compare these criteria. Data of 69 patients with aggressive non-Hodgkin lymphoma (AGR-NHL) who underwent FDG PET/CT at the end of therapy and were followed up for a minimum period of 1 year (median follow-up period 17 months) were evaluated. Twenty-eight of the 69 patients were found to have residual/recurrent disease during follow-up. The accuracy for predicting residual disease of International Harmonization Project (IHP) criteria, London criteria and Gallamini criteria was 71.0%, 84.0% and 88.4%, respectively. Gallamini and London criteria had greater accuracies in predicting residual disease than IHP criteria (p = 0.0001). The major difference in accuracy was due to the low positive predictive value of IHP criteria. Positive predictive values (PPVs) of both London and Gallamini criteria (79.3% and 88.5%, respectively) were high when compared with that of IHP criteria (60.5%) (p = 0.001). Negative predictive values (NPVs) were similar for all the criteria. In conclusion, Gallamini and London criteria had higher accuracy when interpreting end of therapy FDG PET/CT studies in AGR-NHL. London criteria can be used preferentially over Gallamini criteria because of simplicity in interpretation and reproducibility.

Role of F-18 FDG PET/CT in assessing bone marrow involvement in pediatric Hodgkin's lymphoma.

OBJECTIVES: The aim of the current study was to assess the utility of F-18-fluoro-2-deoxy-D-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) in assessing bone marrow involvement (BMI) compared to bone marrow biopsy (BMB) in initial staging of Hodgkin's lymphoma (HL) in pediatric patients. METHODS: Data of 38 pediatric patients (mean age 9.8 years, range 3-18 years) with HL were analyzed for the involvement of bone marrow. All patients underwent non-contrast F-18 FDG PET/CT study. BMB was done in 31 patients from the bilateral iliac crests. Scans were interpreted by two nuclear medicine physicians blinded to the details of BMB. RESULTS: Of the 31 patients who underwent BMB, 5 patients had lymphomatous involvement on BMB. PET/CT was positive in four of these five patients. In 26 patients negative on BMB, PET was negative in 23 patients and positive in 3 patients for BMI. The sensitivity and negative predictive value of F-18 FDG PET/CT was 87.5 and 96%, respectively, for BMI. CONCLUSIONS: F-18 FDG PET/CT can predict BMB results with high accuracy. F-18 FDG PET/CT may be used at initial staging of pediatric Hodgkin's lymphoma as it uncovers unsuspected BMI and BMB may be omitted in patients with PET-positive BMI.

Metastatic lung nodule diagnosed on 18F-FDG PET/CT-guided fine needle aspiration in a patient with renal cell carcinoma.

Computed tomography (CT)-guided fine-needle aspiration cytology is an essential procedure in establishing the malignant nature of either primary or metastatic lung nodules. However, false-negative findings may result from aspiration of low-cellular areas because true metabolic and cellular tumor volume cannot be identified by anatomic imaging alone. The authors describe a case of renal cell carcinoma with a lung nodule where the highly metabolic intratumoral area was demonstrated on FDG PET/CT, after which the PET/CT-guided fine-needle aspiration cytology established the malignant nature of the nodule.

Incidental detection of a vesicocolonic fistula on renal scintigraphy with SPECT/CT.

Urinary-enteric fistula is a rare cause of recurrent urinary tract infection (UTI). Therefore, delayed/incidental diagnosis is the rule. The authors present an image of a vesicocolonic fistula incidentally detected during SPECT/CT renal scintigraphy with 99mTc-DTPA in a female patient with recurrent UTI. The diagnosis was subsequently confirmed by cystoscopy and surgery.

Factors predicting treatment failure in patients treated with iodine-131 for graves' disease.

Treatment of Graves' disease with iodine-131 ((131)I) is well-known; however, all patients do not respond to a single dose of (131)I and may require higher and repeated doses. This study was carried out to identify the factors, which can predict treatment failure to a single dose of (131)I treatment in these patients. Data of 150 patients with Graves' disease treated with 259-370 MBq of (131)I followed-up for at least 1-year were retrospectively analyzed. Logistic regression analysis was used to predict factors which can predict treatment failure, such as age, sex, duration of disease, grade of goiter, duration of treatment with anti-thyroid drugs, mean dosage of anti-thyroid drugs used, (99m)Tc-pertechnetate ((99m)TcO4 (-)) uptake at 20 min, dose of (131)I administered, total triiodothyronine and thyroxine levels. Of the 150 patients, 25 patients required retreatment within 1 year of initial treatment with (131)I. Logistic regression analysis revealed that male sex and (99m)TcO4 (-) uptake were associated with treatment failure. On receiver operating characteristic (ROC) curve analysis, area under the curve (AUC) was significant for (99m)TcO4 (-) uptake predicting treatment failure (AUC = 0.623; P = 0.039). Optimum cutoff for (99m)TcO4 (-) uptake was 17.75 with a sensitivity of 68% and specificity of 66% to predict treatment failure. Patients with >17.75% (99m)TcO4 (-) uptake had odds ratio of 3.14 (P = 0.014) for treatment failure and male patients had odds ratio of 1.783 for treatment failure. Our results suggest that male patients and patients with high pre-treatment (99m)TcO4 (-) uptake are more likely to require repeated doses of (131)I to achieve complete remission.

Asymptomatic Distant Subcutaneous Metastases Detected by (18)F-FDG-PET/CT in a Patient with Breast Carcinoma.

Cutaneous metastases from internal malignancies are rare with a reported incidence between 0.7% and 10%. We report a case with distant skin and subcutaneous metastases in abdominal skin from breast cancer detected on (18)F-fluoro-deoxyglucose-positron emission tomography/computed tomography imaging.

FDG PET/CT in Detection of Metastatic Involvement of Heart and Treatment Monitoring in Non-Hodgkin's Lymphoma.

Cardiac metastasis occurs in up to a quarter of patients with metastatic cancer and is seen most commonly in melanoma and lymphoma. Metastatic involvement of the heart and pericardium may go unrecognized until autopsy. We describe a patient of non-Hodgkin's lymphoma detected to have involvement of right atrium on F-18 FDG PET/CT and monitoring of response to chemotherapy.

Comparison of nitrate augmented Tc-99m tetrofosmin gated SPECT imaging with FDG PET imaging for the assessment of myocardial viability in patients with severe left ventricular dysfunction.

BACKGROUND: Of various nuclear medicine techniques, F-18/flourodeoxyglucose (FDG) positron emission tomography (PET) is considered as the best modality for the assessment of viable myocardium (VM). In this study, we compared the diagnostic accuracy of nitrate augmented Tc-99m tetrofosmin gated G-single-photon emission computed tomography (SPECT) with FDG PET. METHODS: 54 consecutive cases of angiographically proven CAD with severe LV dysfunction were enrolled in the study. The patients underwent Tc-99m tetrofosmin G-SPECT and FDG PET as per the standard protocols and were compared. RESULTS: SPECT data analysis indicated functional abnormalities in 661/918 myocardial segments. F-18 FDG PET revealed VM in 496/661 segments. The diagnostic accuracy of baseline NAC, postnitrate NAC, baseline AC, and postnitrate AC Tc-99m tetrofosmin SPECT was 84%, 87%, 90%, and 94%, respectively. κ values for NAC baseline, NAC postnitrate, AC baseline, and AC postnitrate Tc-99m tetrofosmin G-SPECT were 0.65, 0.70, 0.77, and 0.85, respectively. Attenuation correction revealed viability additionally in 46 segments which were non-viable on NAC postnitrate study (P < .001). Nitrate augmentation showed viability additionally in 25 segments which were non-viable on AC baseline scan (P = .004). On patient-based analysis FDG PET changes the management only in 13% (7/54) of patients. CONCLUSIONS: Nitrate augmented AC Tc-99m tetrofosmin G-SPECT shows excellent (κ = .85) agreement with FDG PET. FDG PET changes management only in 13% of the patients. Tc-99m tetrofosmin G-SPECT being more widely available and cheaper imaging modality can be reliably used to detect VM where FDG PET is not available.

Radioiodine treatment in McCune-Albright syndrome with hyperthyroidism.

McCune-Albright syndrome (MAS) is a sporadic disease characterized by polyostotic fibrous dysplasia, "café-au-lait" spots and hyperfunctional endocrinopathies. Pathophysiological basis is activating mutation of the gene that encodes the alpha subunit of Gs membrane protein that stimulates the intracellular production of cAMP, conferring autonomous secretion of the gland in particular. One of the uncommon endocrine manifestations is hyperthyroidism. We present a patient who had café-au-lait spots, polyostotic fibrous dysplasia and hyperthyroidism. She was treated with radioactive iodine for the symptoms of hyperthyroidism and subsequently relieved from hyperthyroid features.

Prognostic value of quantitative parameters derived on initial staging 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with high-grade non-Hodgkin's lymphoma.

OBJECTIVES: This study was carried out to evaluate the role of quantitative parameters in staging PET in predicting prognosis in patients with high-grade non-Hodgkin's lymphoma (NHL). METHODS: A total of 51 histopathologically proven high-grade NHL patients treated with conventional chemotherapy regimens were included in the study. Total lesion glycolysis (TLG) and functional volumes (FVs) were defined as per the PET Response Criteria in Solid Tumors (PERCIST) criteria. All patients were followed up for a minimum period of 1 year or until an event, whichever occurred earlier. RESULTS: Of the four semiquantitative parameters studied, SUV max and SUV mean did not show a statistically significant correlation with progression-free survival or overall survival, whereas TLG and FV showed a weak but statistically significant negative correlation. Using the receiver operating characteristic curve analysis, optimal cut-offs were derived for FV and TLG to predict progression and death. Using the cut-off values of 416 cm3 and 3340 g for FV and TLG, respectively, a statistically significant difference in progression-free survival and overall survival was obtained in the groups with FV and TLG above and below the threshold. On multivariate analysis of all the conventional prognostic factors and TLG more than 3340 and FV more than 416 cm3, only age greater than 60 years (P=0.013) and FV more than 416 cm3 (P=0.012) were found to be independently associated with disease progression. CONCLUSION: Our results indicate that FV and TLG in staging PET/CT could be useful indices in predicting outcomes in patients with high-grade NHL treated with standard first-line chemotherapy regimens.

A rare case of malignant urinary bladder paraganglioma with distant metastases demonstrated by 18F-FDG PET/CT.

Urinary bladder paragangliomas are rare tumors, with malignant ones being still rarer. Demonstration of metastases by imaging is crucial, as histological examination of primary cannot reliably distinguish between benign and malignant tumors. We describe a rare case of a patient with malignant urinary bladder paraganglioma in whom 18F-FDG PET/CT was useful in detection of regional lymph nodal and distant metastases. In addition, 18F-FDG PET/CT suggested an easily accessible site of biopsy to confirm the metastatic disease.

Clinical utility of F-18 FDG PET/CT in recurrent breast carcinoma.

PURPOSE: Although initial studies have shown the utility of fluorine-18 fluorodeoxyglucose (F-18 FDG) PET in the detection and restaging of recurrent breast carcinoma, scarce literature exists on F-18 FDG PET/computed tomography (CT). This retrospective study was carried out to evaluate the role of F-18-FDG PET/CT in recurrent breast carcinoma and its impact on management. MATERIALS AND METHODS: Retrospective analysis of data of 111 patients who underwent F-18 FDG PET/CT and were suspected of having recurrent breast carcinoma was carried out. PET/CT imaging was carried out for distant metastases in histologically proven locoregional recurrence in 23 patients, clinically suspicious locoregional recurrence in nine patients, increasing tumour markers in two patients, suspicion of distant metastatic disease in 61 patients or as a part of surveillance in 16 patients. The final diagnosis of recurrence and stage of disease was made after histopathological analysis, correlative imaging and clinical or imaging follow-up of at least 6 months. RESULTS: The final diagnosis of recurrent breast carcinoma was made in 76 patients and no evidence of recurrence was found in the remaining 35 patients. Locoregional disease requiring local radiotherapy or surgery was diagnosed in 14 patients and distant metastatic disease was diagnosed in 62 patients. FDG PET/CT was true positive in 75 patients, false positive in six patients, true negative in 35 patients and false negative in one patient, with a sensitivity, specificity, positive predictive value and a negative predictive value of 98.7, 85.3, 92.5 and 97.2%, respectively. FDG PET/CT also accurately restaged 22/23 patients with proven locoregional recurrence with an accuracy of 95.45%. Of 53 patients suspected of having distant metastatic disease on other imaging modalities, true distant metastatic disease was diagnosed in 36 patients and FDG PET/CT identified true metastatic disease in 35/36 patients, accurately ruling out metastases in the remaining 17 patients, and was false negative in one patient. In addition to confirming distant metastatic disease, it revealed more metastatic sites in 22 patients. Overall, F-18 FDG PET/CT had a major impact on management in 41% of the 103 patients being analysed for a major change in treatment. CONCLUSION: F-18 FDG PET/CT is a very sensitive and specific imaging tool in detecting and restaging recurrent breast carcinoma. It can be a very useful imaging tool for restaging locoregional recurrences, and as a one-stop shop imaging technique to confirm suspicious metastatic disease on conventional imaging and to define the total burden of disease.