Advantage of Hybrid 18F-Fluoride Positron Emission Tomography/Computed Tomography to Diagnose Malignant Rib Invasion by Pleural Metastasis in a Background of Reactive Periostitis.

Diffuse osteoblastic activity in the ribs on bone scan is seen in association with pleural thickening. Irrespective of the pleural pathology, this represents benign finding caused by pleural hyperemia or reactive periostitis, with preserved cortical integrity. However, malignant involvement of the ribs can occur by local invasion of pleural malignancy causing cortical lysis. Herein, we describe the 18F-fluoride positron emission tomography/computed tomography findings of reactive periostitis of the ribs in pleural metastasis and emphasize the advantage of hybrid imaging in detecting local malignant tumor invasion superimposed in such condition.

Obstructive Jaundice: An Unusual Presentation of Neuroendocrine Differentiation in Prostatic Adenocarcinoma.

An elderly male on androgen deprivation therapy for prostatic adenocarcinoma presented with obstructive jaundice. Since biopsy from the head of the pancreas showed neuroendocrine carcinoma (NEC), he was diagnosed with second primary pancreatic NEC. Ga-68 DOTANOC positron emission tomography/computed tomography (PET/CT) done subsequently showed enlarged mildly DOTANOC-avid retroperitoneal nodes infiltrating the pancreas. These nodes were found to be progression of prostate-specific membrane antigen (PSMA) nonavid retroperitoneal nodes visualized in his Ga-68 PSMA PET/CT performed at another institution before 4 months, when there was no lesion in the pancreas. This observation revised the diagnosis from second primary pancreatic NEC to progression of neuroendocrine differentiation in preexisting prostatic adenocarcinoma.

Delayed 68Ga-PSMA PET/CT Image-Guided Biopsy for Low-Grade Adenocarcinoma in Benign Prostatic Hyperplasia.

ABSTRACT: Image-guided biopsy of prostate with multiparametric MRI is being adopted in the workup of prostate adenocarcinoma (PAC). 68Ga-PSMA PET/CT-guided biopsy has also been shown to be equally sensitive in the evaluation of higher-grade tumors with increased PSMA expression. The sensitivity of 68Ga-PSMA PET/CT, however, reduces with lesser PSMA expression in low-grade PAC. Herein, we demonstrate a case where delayed 68Ga-PSMA PET/CT imaging helped in detecting low-grade PAC in BPH.

De Novo Presentation of Sarcoidosis on Restaging FDG PET/CT in Rectal Carcinoma With Self-resolution.

Sarcoidosis is a systemic disorder of unknown etiology characterized by development of noncaseating granulomas in more than 1 organ system. Development of sarcoidosis during or immediately after chemotherapy and immunotherapy is not uncommon. We present a 61-year-old woman in whom restaging F-FDG PET/CT detected asymptomatic sarcoidosis after neoadjuvant chemoradiotherapy for carcinoma rectum, which resolved spontaneously by the end of adjuvant chemotherapy with no specific treatment. Recognition of anatomic-metabolic pattern of sarcoidosis could prevent erroneous upstaging of the primary malignancy during restaging PET/CT following chemotherapy, and such lesions may show self-resolution.

Fluorodeoxyglucose-positron emission tomography/computed tomography performs better than contrast-enhanced computed tomography for metastasis evaluation in the initial staging of pancreatic adenocarcinoma.

OBJECTIVE: To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma. METHODS: 54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar's test. RESULTS: Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients. CONCLUSION: FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.

Contrast-enhanced fluorodeoxyglucose positron emission tomography/computed tomography in solid pseudopapillary neoplasm of the pancreas.

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare pancreatic tumor with low malignant potential. It occurs characteristically more often in young women. Radiological and pathological studies have revealed that the tumor is quite different from other pancreatic tumors. Limited information is available in the literature reporting their accumulation of fluorine-(18) fluorodeoxyglucose ((18)F-FDG) in positron emission tomography/computed tomography (PET/CT). Here, we report a case of pancreatic SPN imaged with contrast-enhanced FDG PET/CT. A percutaneous fine needle aspiration from the metabolically active lesion revealed SPN, and it was confirmed with histopathological results. Recurrence or metastasis was not found after 7 months of follow-up.

A rare case of asymptomatic radioiodine-avid renal and brain metastases 20 years after hemi-thyroidectomy for adenomatous goiter.

A 65-year-old patient, with a history of left hemi-thyroidectomy for adenomatous goiter 20 years previously, was found to have pulmonary lesions on chest X-ray, a brain lesion on computerized tomography (CT), and elevated serum thyroglobulin (Tg). While completion thyroidectomy revealed that no pathological evidence of thyroid malignancy, radioiodine-avid pulmonary, brain, and renal and bone lesions were identified on diagnostic as well as posttherapy whole body planar scintigraphy and single photon emission computed tomography-CT. Subsequent ultrasonography-guided biopsy of a renal nodule showed thyroid follicular cells. This case suggests that metastatic differentiated thyroid carcinoma should be suspected in asymptomatic patients with incidentally detected lesions, raised serum Tg, and history of thyroid lesions.

Noninvasive evaluation of active pan-ulcerative colitis with multiple strictures using Fluorine-18-Fluorodeoxyglucose positron emission tomography/computed tomography.

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by waxing and waning inflammation that changes in severity and extent and may progress to neoplasia, especially in the presence of strictures. When patients have nonnegotiable strictures or severe inflammation with ulcers, colonoscopy is difficult and carries the risk of perforation. The authors present a patient with pan-UC with multiple strictures, in whom fluorodeoxyglucose positron emission tomography/computed tomography was used to noninvasively evaluate the extent and severity of the disease.

Contrast-enhanced fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography in mediastinal T-cell lymphoma with superior vena cava syndrome.

Positron emission tomography-computed tomography (PET/CT) is a routine investigation for the staging of lymphomas. Contrast-enhanced computed tomography is mandatory whenever parenchymal lesions, especially in the liver and spleen are suspected. We report a rare case of primary mediastinal T-cell lymphoma evaluated with contrast-enhanced PET/CT that showed features of superior vena cava syndrome.

Diagnostic accuracy of F-18 FDG PET/CECT vs. CECT for detecting recurrence of periampullary carcinoma and its prognostic significance.

PURPOSE: To evaluate the additive value of whole-body F-18 fluoro-deoxyglucose positron emission tomography (FDG PET) as an adjunct to contrast-enhanced computed tomography (CECT) for detecting recurrence following Whipple's resection for periampullary carcinoma and to analyze the prognostic significance of FDG PET-/CECT-based detection of recurrence. METHODS: Fifty patients (34 males, 16 females; mean age: 55 ± 11 years) who underwent PET/CECT following resection of periampullary carcinoma were included. The study was duly approved by the institutional ethical committee for retrospective analysis of the data. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of FDG PET/CECT and CECT alone for detection of recurrence were calculated, and the accuracy was compared with ROC analysis. The prognostic factors for survival following recurrence were analyzed by univariate and multivariate methods. RESULTS: PET/CECT indicated recurrence of disease in 26 (52%) patients. The overall mean survival time was 46 months with an overall survival rate of 42%. The sensitivity, specificity, PPV, NPV and accuracy of PET/CECT and CECT for detection of recurrence were 96.1%, 91.6%, 92.6%, 95.6%, 94% and 76.9%, 75%, 76.9%, 75%, 76%, respectively (p = 0.037). Also change in management could have been achieved in 18% of patients based on the PET/CECT results. In univariate analyses, SUVmax >7.3 was the only predictor of poor survival (p < 0.05). CONCLUSION: PET/CECT could be used as a one-stop imaging tool for staging and prognostication of recurrent periampullary carcinoma that could result in better patient management.

Metabolic signatures of malignant and non-malignant mass-forming lesions in the periampulla and pancreas in FDG PET/CT scan: an atlas with pathologic correlation.

Positron emission tomography (PET) has been used for the characterization of pancreatic and periampullary lesions. Pancreatitis-associated inflammation affecting only a portion of the pancreas gives the appearance of a mass lesion on imaging. Consequently, the differential diagnosis between cancer and pancreatitis becomes a commonly encountered problem. Traditionally, PET was interpreted as positive (to denote malignancy) if fluorodeoxyglucose (FDG) activity in the pancreas exceeded background activity and as negative (to denote benign) if activity was less than or equal to background activity. However, the specificity was limited with this method of interpretation. A relatively wide overlap has been reported between semiquantitative uptake values obtained in cancers and those in inflammatory lesions. Also, the qualitative (metabolic patterns) and quantitative variables (standardized uptake values) have been complementary and at sometimes controversial to each other in various clinical situations. There is paucity of data in the literature highlighting the role of FDG PET/CT in characterization of such mass lesions. The primary aim of this pictorial review is to list the various pathologic processes of pancreas and periampulla that could be studied with FDG PET/CT and recognize the different FDG uptake patterns and apply this information to characterize the different lesions affecting the pancreas and periampulla. We have also discussed the limitations of conventional imaging and advantages of FDG PET/CT for the evaluation mass-forming lesions of the pancreas and periampulla.

Pancreatic tuberculosis: Evaluation of therapeutic response using F-18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography.

F-18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET/CT) is a functional imaging technique that monitors glucose metabolism in tissues. Pulmonary tuberculosis (TB) has been reported to show intense uptake of FDG, with a decrease in metabolism of the tuberculous lesions after successful anti-tubercular treatment (ATT). The authors present a patient with pancreatic TB and demonstrate the usefulness of FDG PET/CT in monitoring the response to ATT.

Pyrexia, Lung nodules, Granulomas: Pulmonary Lymphomatoid Granulomatosis.

The differential diagnosis of pyrexia, lung nodules and granulomas includes tuberculosis, vasculitis and rarely a malignancy. In countries where tuberculosis or histoplasmosis is endemic, these are the first consideration and often ruled out by microbiological investigations. Vasculitis like granulomatosis with polyangitis (Wegener's granulomatosis), Churg strauss syndrome and sarcoidosis, which are the second consideration, are ruled out by serological investigations. Confirmation of malignancy merits histopathology. This case highlights how a rare diagnosis of pulmonary lymphomatoid granulomatosis was reached after an open lung biopsy. The following case also describes the natural history of this rare disease as it showed transient spontaneous remission but ultimately required therapy.

Comparison of LVEF assessed by 2D echocardiography, gated blood pool SPECT, 99mTc tetrofosmin gated SPECT, and 18F-FDG gated PET with ERNV in patients with CAD and severe LV dysfunction.

INTRODUCTION: Left ventricular ejection fraction (LVEF) is the single most important predictor of prognosis in patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction. Equilibrium radionuclide ventriculography (ERNV) is considered the most reliable technique for assessing LVEF. Most of these patients undergo two dimensional (2D) echocardiography and myocardial viability study using gated myocardial perfusion imaging (MPI) or gated F-fluorodeoxyglucose (F-FDG) PET. However, the accuracy of LVEF assessed by these methods is not clear. This study has been designed to assess the correlation and agreement between the LVEF measured by 2D echocardiography, gated blood pool single photon emission computed tomography (SPECT), Tc tetrofosmin gated SPECT, and F-FDG gated PET with ERNV in CAD patients with severe LV dysfunction. PATIENTS AND METHODS: Patients with CAD and severe LV dysfunction [ejection fraction (EF) <35 assessed by 2D echocardiography] were prospectively included in the study. These patients underwent ERNV along with gated blood pool SPECT, Tc tetrofosmin gated SPECT, and F-FDG gated PET as per the standard protocol for myocardial viability assessment and LVEF calculation. Spearman's coefficient of correlation (r) was calculated for the different sets of values with significance level kept at a P-value less than 0.05. Bland-Altman plots were inspected to visually assess the between-agreement measurements from different methods. RESULTS: Forty-one patients were prospectively included. LVEF calculated by various radionuclide methods showed good correlation with ERNV as follows: gated blood pool SPECT, r=0.92; MPI gated SPECT, r=0.85; and F-FDG gated PET, r=0.76. However, the correlation between 2D echocardiography and ERNV was poor (r=0.520). The Bland-Altman plot for LVEF measured by all radionuclide methods showed good agreement with ERNV. However, agreement between 2D echocardiography and ERNV is poor, as most of the values in this plot gave a negative difference for low EF and a positive difference for high EF. The mean difference between various techniques [2D echocardiography (a), gated blood pool SPECT (b), MPI gated SPECT (c), F-FDG gated PET (d)] and ERNV (e) was as follows: (a)-(e), 3.3; (b)-(e), 5; (c)-(e), 1.1; and (d)-(e), 2.9. The best possible correlation and agreement was found between MPI gated SPECT and ERNV. CONCLUSION: This study showed good correlation and agreement between MPI gated SPECT and F-FDG gated PET with ERNV for LVEF calculation in CAD patients with severe LV dysfunction. Thus, subjecting patients who undergo viability assessment by MPI gated SPECT or F-FDG gated PET to a separate procedure like ERNV for LVEF assessment may not be warranted. As the gated blood pool SPECT also showed good correlation and agreement with ERNV for LVEF assessment in CAD patients with severe LV dysfunction, with better characteristics than ERNV, it can be routinely used whenever accurate LVEF assessment is needed.

Is femoral uptake of Tc99m-methylene diphosphonate on bone scintigraphy in bronchogenic carcinoma an alarming sign: A case report and brief review of literature?

Detection of skeletal metastasis in patients with lung cancer is important from management point of view. We report the bone scan finding in a patient with non-small cell lung carcinoma showing isolated abnormal tracer in femur and having a characteristic appearance in computed tomography, highlighting the importance of bone scan in patients with bronchogenic carcinoma.

Dual-phase 18F-FDG PET/CT imaging in the characterization of pancreatic lesions: does it offer prognostic information?

OBJECTIVE: The primary aim of our prospective study was to evaluate the usefulness of dual-phase F-fluoro-deoxy-glucose PET/computed tomography (F-FDG PET/CT) in the characterization of pancreatic masses. The secondary aim was to assess whether delayed imaging revealed any prognostic information. MATERIALS AND METHODS: Fifty patients with periampullary or pancreatic masses on conventional imaging were included in this study. Early and delayed PET/CT was performed, followed by pathological examination in all patients. PET/CT parameters including uptake pattern, SUVearly, SUVdelayed, lesion to background ratio (L/B), and retention index (RI) were assessed for their ability to differentiate benign from malignant lesions. Patients with malignant lesions were followed up for a median duration of 26 months. The association of 11 variables with survival was analyzed by univariate and multivariate methods. RESULTS: Thirty-one patients had malignant lesions and 19 had benign lesions. The mean SUVearly, L/B, SUVdelayed, and RI between the malignant and benign lesions were statistically significant. The F-FDG uptake pattern of the lesions had higher sensitivity (93.5%) and specificity (100%) compared with RI (cutoff 25.7%) (84 and 37%, respectively) for diagnosing malignancy (P<0.05). In univariate analysis both RI (>18.7%) and tumor size (>2.6 cm) predicted significantly poor survival, whereas in multivariate analysis RI (P=0.04) was the only predictor of poor survival. CONCLUSION: Dual-phase F-FDG PET/CT is not useful in characterizing pancreatic masses as it cannot differentiate benign from malignant lesions, and focal uptake on early PET imaging is the best indicator of malignancy. A possible benefit in performing a delayed scan is that a high RI (>18.7) can predict poor survival and hence may be useful in treatment planning.

F-18 FDG PET/CT in the evaluation of Takayasu arteritis: an experience from the tropics.

OBJECTIVE: To evaluate the performance parameters of FDG PET/CT in patients with Takayasu arteritis at diagnosis and during immunosuppression. METHODS: Retrospective analysis of 60 FDG PET/CT studies in 51 patients was performed (17 scans at diagnosis out of which 4 had follow-up scans also and 43 scans on immunosuppression). The degree of FDG uptake in the vessels was assessed visually using a 4-point scale and maximum standardized uptake value (SUVmax), SUVratio, extent of vasculitis and association with ESR were calculated. RESULTS: PET/CT was positive for active vasculitis in all 17 patients at diagnosis. The mean SUVmax and mean SUV ratio of the active areas were 5.1 ± 3.0 and 3.2 ± 1.9, respectively. On immunosuppression, PET scan was positive for active vasculitis in 14/43 (32.5%) scans. The mean SUVmax and mean SUVratio of the active areas were 1.7 ± 2.1 and 0.95 ± 1.2, respectively. There was significant difference between the mean SUVmax and mean SUVratio at diagnosis and on immunosuppression, respectively (P < .01). The median number of vascular segments in each uptake grade group was also statistically different (P < .01) between scans at diagnosis and on immunosuppression. The median ESR level in PET positive scans was 29 mm/hour (2-53), whereas in PET negative scans was 35.5 mm/hour (6-50) and the difference was not statistically significant. CONCLUSION: FDG PET/CT showed good sensitivity to detect active vasculitis at diagnosis and during immunosuppression. The change in SUVmax between the successive FDG PET/CT scans may give an objective assessment of response to immunosuppression.

Isolated cerebellar hypermetabolism on FDG PET in a case of remitted primary breast lymphoma.

We present here a case of primary non-Hodgkin's lymphoma of the breast that succumbed in a sub-acute course to death after three months of initial remission. The fluorodeoxyglucose positron emission tomography imaging during the declining clinical status showed isolated cerebellar hypermetabolism.

Role of F18 fluorodeoxyglucose positron-emission tomography/computed tomography in the management of Askin's tumor.

A primitive neuroectodermal tumor (PNET) of the thoraco-abdominal region is one of a group of small round cell tumors usually found in children and young adults, originally described by Askin et al. Most cases arise in the soft-tissues of the thorax, but may rarely occur within the lung with the symptoms of chest wall pain, pleural effusion and dyspnea. The authors present two cases demonstrating the utility of F18 fluorodeoxyglucose positron-emission tomography/computed tomography in the staging and prognosis of PNET of the chest wall.