Kuruva Manohar

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.

Can fluorodeoxyglucose positron emission tomography/computed tomography avoid negative iliac crest biopsies in evaluation of marrow involvement by lymphoma at time of initial staging?

Abstract The assessment of bone marrow involvement (BMI) is important for accurate prognostication and deciding the appropriate therapy in patients with lymphoma. Conventional bilateral iliac crest biopsies (ILBMBs) have many limitations. F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is a useful investigative tool for detecting BMI. F-18 FDG PET/CT data for 97 patients with either non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma (HL) were analyzed. ILBMB was performed 7–10 days later. A final diagnosis of BMI was made in 38/97 patients on the basis of composite criteria derived from both FDG PET/CT and ILBMB results. ILBMB detected BMI in 29/38 patients, 2/5 patients with HL, 27/33 patients with NHL, 19/25 patients with aggressive NHL, and 8/8 patients with indolent NHL with a sensitivity of 76%, 40%, 82%, 76%, and 100%, respectively. FDG PET/CT was true positive for BMI in 5/5 patients with HL and 29/33 patients with NHL, comprising 25/25 patients with aggressive NHL and 4/8 patients with indolent NHL, with a sensitivity of 100%, 88%, 100%, and 50%, respectively. FDG PET/CT performed better than ILBMB in cases of HL and aggressive NHL, but its sensitivity was poor in cases of indolent lymphoma. In addition, FDG PET/CT had a very high negative predictive value approaching 100% in HL and aggressive NHL, which might help in avoiding negative ILBMBs.

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.

ObjectivesThis 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). MethodsA 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. ResultsOf the four semiquantitative parameters studied, SUVmax and SUVmean 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. ConclusionOur 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.

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

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

ObjectivesThis study was conducted to evaluate the role of 18F-fluorodeoxyglucose (18F-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 methodsForty-three consecutive patients with histopathologically proven LABC with negative conventional imaging results for distant metastases were included in the study. All of them underwent 18F-FDG PET/CT within a week after conventional imaging. Results 18F-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 18F-FDG PET/CT for distant metastases developed distant metastases during the follow-up. 18F-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, 18F-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 18F-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.

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 18F-fluoro-deoxyglucose–positron emission tomography/computed tomography imaging.

Polycystic kidney disease: renal cyst infection detected on F-18 FDG PET/CT.

Cyst infection within a polycystic kidney is a serious complication, potentially leading to abscess, sepsis, and death. Diagnosis of renal cyst infection is usually based on positive blood cultures in the presence of fever and renal tenderness. The authors present an image that shows F-18 FDG concentration in multiple infected cysts in a patient with polycystic kidney disease, with resolution after adequate antibiotic treatment.

Renal cell carcinoma presenting as isolated thyroid metastasis 13 years after radical nephrectomy, detected on F-18 FDG PET/CT.

We report a case of renal cell carcinoma presenting as isolated thyroid metastasis, 13 years after radical nephrectomy for the primary disease. F-18 FDG PET/CT provided valuable information regarding thyroid being the only site of metastatic involvement, which lead to further appropriate management.

Concurrent sublingual thyroid and thyroglossal cyst with functioning thyroid tissue in the absence of an orthotopic thyroid gland

The prevalence of ectopic thyroid tissue is approximately 1/100 000–300 000 persons and is reported to occur in one in 4000–8000 patients with thyroid disease. It is the only thyroid in 70% of all cases, and identifi cation of functioning thyroid tissue in the orthotopic gland is crucial, as it would infl uence surgical management. Technetium-99m pertechnetate scintigraphy is routinely used to acquire functional information on both normal and ectopic thyroid glands. The authors report a rare case of a thyroglossal cyst with functioning thyroid tissue in it coexisting with a functioning sublingual thyroid, without any orthotopic thyroid gland in the neck. The detection of functioning thyroid tissue in a thyroglossal cyst is important when surgical management is contemplated. The technetium-99m pertechnetate (Tco4 ) thyroid scan is routinely used for identifying ectopic thyroid glands. We describe here an unusual case of a thyroglossal cyst with functioning thyroid tissue coexisting with a functioning sublingual thyroid, without an orthotopic thyroid gland in the neck, documented during a routine Tco4 − scan. A 16-year-old boy with no clinical signs or symptoms of physical or mental retardation presented with progressive swelling in the anterior neck, fi rst noticed when he was 5 years old. Physical examination revealed a 3to 4-cm mobile, nontender, midline swelling with a smooth surface and fi rm consistency that moved with deglutition and protrusion of the tongue. The thyroid profi le was as follows: total triiodothyronine (T3) 110 ng/ dl (normal 86–186), total thyroxine (T4) 5.5 g/dl (normal 4.5–12.5), and thyroid-stimulating hormone (TSH) 111 μIU/ml (normal 0.25–4.5 μIU/ml). He was not taking any supplementary thyroid hormone treatment. Thyroid scintigraphy was performed 20 min after intravenous injection of 4 mCi (148 MBq) of Tco4 . A static anterior planar image was acquired for 250 000 counts (Fig. 1), followed by a lateral view with markers (not shown here). A well-defi ned focus of tracer concentration was seen in the fl oor of the mouth with diffuse, globular tracer uptake immediately below, corresponding to the clinically palpable mass. Hybrid single photon emission computed tomography/computed tomography (SPECT/CT) of the head and neck region (Fig. 2) on a dual-head gamma camera localized the upper focus to the sublingual region, confi rming a functioning ectopic Received: March 22, 2010 / Accepted: May 24, 2010

Orbital Metastases as Presenting Sign of Lung Carcinoma: Detection of Primary Malignancy and Disease Burden by F-18 FDG PET/CT

Metastases to orbit occur rarely but are the most common form of malignant orbital tumors. Usually the orbital metastases occur in disseminated disease. Very rarely orbital metastases can be the presenting feature of systemic malignancy. We report here a case with orbital metastases as the presenting feature of lung malignancy and describe the utility of FDG PET/CT as one-stop-shop imaging modality in this setting.