Anna Margherita Maffione

Diagnostic Accuracy of 11C-Choline PET/CT in Preoperative Lymph Node Staging of Bladder Cancer: A Systematic Comparison With Contrast-Enhanced CT and Histologic Findings

Aim The aim of this study was to evaluate the role of 11C-choline PET/CT in the preoperative evaluation of the nodal involvement of patients with bladder carcinoma (BC) suitable for radical cystectomy and extended pelvic lymph node dissection in comparison with contrast-enhanced CT (CECT) using the pathologic specimen as reference standard. Patients and Methods Twenty-six consecutive patients (69.5 ± 9.3 years; range, 49–84) with histologically proven transitional cell BC were treated with radical cystectomy and pelvic lymph node dissection and were enrolled from April 2011 to January 2013. In all patients, paravesical, internal, eternal, and common iliac nodes as well as obturatory, presacral, preaortic, and precaval lymph nodes (LNs) were dissected up to the origin of the inferior mesentery artery. The areas of the LN dissection were grouped as follow: region A included preaortic and precaval LNs; region B included paravesical, common, internal and external iliac, obturatory, and presacral LNs in the right pelvis; region C included paravesical, common, internal and external iliac, obturatory, and presacral LNs in the left pelvis. 11C-choline PET/CT and abdominal CECT were used to assess the presence of lymph node metastases on a per patient, region, and lesion analysis using the results of surgical specimens obtained at operation as criterion standard. Results Seven of 26 patients (26.9%) showed nodal metastases at pathologic analysis. Overall, 844 LNs were evaluated, and 38 of them (4.5%) showed metastatic involvement. On a patient-based analysis, 11C-choline PET/CT showed a sensitivity of 42% and specificity of 84%, whereas, CECT showed a sensitivity of 14% and specificity of 89%. On a region-based analysis, 11C-choline PET/CT showed a sensitivity of 11% and specificity of 82%, whereas CECT showed a sensitivity of 5% and specificity of 80%. On a lesion (LN)-based analysis, 11C-choline PET/CT showed a sensitivity of 10% and specificity of 64%, whereas CECT showed a sensitivity of 2% and specificity of 63%. Conclusions 11C-choline PET/CT could provide additional diagnostic information in preoperative nodal staging of patients with invasive BC in comparison with CECT. A study with a larger population should determine if 11C-choline PET/CT could be recommended as a routine technique in high-risk patients with BC.

Comparison between anatomical cross-sectional imaging and 18F-FDG PET/CT in the staging, restaging, treatment response, and long-term surveillance of squamous cell head and neck cancer: A systematic literature overview

The outcome of head and neck squamous cell cancer depends primarily on its prompt diagnosis and treatment. Unfortunately, in many cases ominous prognostic factors such as lymph node metastases or osteomandibular extension are present at the time of diagnosis. We review the relative efficacy of contrast-enhanced computed tomography (ceCT), MRI, and 18F-fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in the early detection of head and neck squamous cell cancer, as well as its impact on treatment management and outcomes. Medline and Web of Knowledge databases, from 2000 to January 2013, were evaluated. Ninety-seven reports were selected, but only 11 studies comparing PET or PET/CT with CT and 11 comparing PET or PET/CT with MRI were found appropriate for analysis. ceCT and MRI continue to be the reference imaging modalities for the study of primary tumors, especially in the evaluation of the extension of disease and its relationship with nearby anatomical structures. There is increasing evidence that 18F-FDG PET/ceCT can provide accurate anatomical details similar to ceCT alone, as well as accurate information on osteomandibular tumor invasion similar to MRI. The major advantage of PET/CT over other imaging methods is its ability to detect relatively small lymph node metastases located in difficult-to-interpret positions. PET/CT is also highly sensitive for the detection of distant metastases and in assessing the response to chemotherapy or chemoradiation treatment and in predicting outcome. ceCT and MRI are the gold standards for evaluating primary and osteomandibular tumoral infiltration. 18F-FDG PET/CT plays a major role in the detection of lymph node and distant metastases, in assessing the response to neoadjuvant/adjuvant chemotherapy or chemoradiation therapy, and in predicting outcome.

New acquisition protocol of 18F-choline PET/CT in prostate cancer patients: review of the literature about methodology and proposal of standardization.

Purpose. (1) To evaluate a new acquisition protocol of 18F-choline (FCH) PET/CT for prostate cancer patients (PC), (2) to review acquisition 18F-choline PET/CT methodology, and (3) to propose a standardized acquisition protocol on FCH PET/CT in PC patients. Materials. 100 consecutive PC patients (mean age 70.5 years, mean PSA 21.35 ng/mL) were prospectively evaluated. New protocol consisted of an early scan of the pelvis immediately after the injection of the tracer (1 bed position of 4 min) followed by a whole body scan at one 1 hour. Early and 1 hour images were compared for interfering activity and pathologic findings. Results. The overall detection rate of FCH PET/CT was 64%. The early static images of the pelvis showed absence of radioactive urine in ureters, bladder, or urethra which allowed a clean evaluation of the prostatic fossae. Uptake in the prostatic region was better visualized in the early phase in 26% (7/30) of cases. Other pelvic pathologic findings (bone and lymph nodes) were visualized in both early and late images. Conclusion. Early 18F-choline images improve visualization of abnormal uptake in prostate fossae. All pathologic pelvic deposits (prostate, lymph nodes, and bone) were visualized in both early and late images.

Proposal of a new 18F-FDG PET/CT predictor of response in rectal cancer treated by neoadjuvant chemoradiation therapy and comparison with PERCIST criteria.

PurposeThe aim of this study was to correlate PERCIST criteria and a new criterion developed in our center that we named PREDIST (PET Residual Disease in Solid Tumor) with tumor regression grade (TRG) classification of pathologic response to neoadjuvant chemoradiotherapy (CRT) in patients affected by rectal cancer. MethodsSeventy-three consecutive patients affected by locally advanced rectal cancer (LARC) were retrospectively included. FDG-PET/CT scans were performed at staging time and after the end of CRT (mean time 6.5 weeks). The analysis was performed by PERCIST criteria 1.0 and PREDIST criteria based on a new definition of residual disease. We split the TRG system into responders (TRG1-2) and nonresponders (TRG3-5). Pearson chi-square analysis by cross-tabulations was performed. ResultsPREDIST classification was statistically predictive of TRG response (P = 0.004, sensitivity 81.8% and specificity 54.9%). On the contrary, PERCIST criteria was not statistically correlated to TRG (P = 0.128) caused by a very low specificity (9.8%). ConclusionsFDG-PET/CT scan is an accurate tool to predict preoperatively the response to CRT in LARC patients. The novel proposed criterion (PREDIST) seems to be helpful to discriminate responder by nonresponder patients.

Restaging clear cell renal carcinoma with 18F-FDG PET/CT.

Aim The aim of our retrospective study was to assess the usefulness of 18F-FDG PET/CT in the restaging of clear cell renal cell carcinoma (RCC) patients. Patients and Methods Sixty-nine patients (median age = 62 years; range = 36–86 years) affected by clear cell RCC (TNM at staging: T1, 42 patients; T2, 13 patients; T3, 11 patients; T4, 3 patients; Fuhrman grade: G2, 47 patients; G3, 20 patients; G4, 2 patients) underwent whole-body 18F-FDG PET/CT to restage the disease after nephrectomy for clinical or radiological suspicion of metastases. Areas of abnormal uptake at PET/CT were classified, taking the liver uptake as reference, as follows: 1 = faint uptake, lower than liver; 2 = moderate uptake, equal to liver; and 3 = high uptake, higher than liver. Validation of 18F-FDG PET/CT results was established by (1) biopsy (23 patients) and (2) other imaging modalities (addressed BS; c.e.CT; MRI; 18F-fluoride PET/CT; subsequent 18F-FDG PET/CT), and/or clinical and radiological follow-up of 12 months (46 patients). Results 18F-FDG PET/CT was positive in 42 patients and negative in 27 patients. Sixteen patients presented single lesions and 26 patients presented multiple localizations of the disease. On a patient basis, 40 patients resulted true positive, 2 patient false positive, 23 patients true negative, and 4 patients false negative. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 90%, 92%, 91%, 95%, and 85%, respectively. On a lesion basis, PET/CT detected 114 areas of abnormal uptake in 42 positive patients of which 112 resulted to be true positive. FDG uptake of the true positive lesions resulted to be high in 83 cases, moderate in 17 lesions, and finally faint in 12 lesions. Conclusions 18F-FDG PET/CT demonstrated a good sensitivity in the restaging of clear cell RCC. Most of the lesions showed intense activity. According to our results, it seems that the use of 18F-FDG PET/CT in the restaging of RCC is feasible because the number of false-negative cases is limited.

18F-DOPA PET/CT in the evaluation of hereditary SDH-deficiency paraganglioma-pheochromocytoma syndromes.

Purpose This study aims to evaluate the role of 18F-DOPA PET/CT in staging and follow-up of paraganglioma syndromes succinate dehydrogenase (SDH)-mutation-related patients, comparing 18F-DOPA PET/CT results with morphological imaging and biochemical results. Patients and Methods We retrospectively studied 10 consecutive patients (3 F, 7 M, mean age 32 yrs), all with a genetically demonstrated SDH mutation (5 SDH-D, 4 SDH-B, and 1 SDH-C) and all addressed to 18F-DOPA PET/CT scan. Seven patients had already been operated on for one or more pheochromocytomas and/or paragangliomas and were submitted to 18F-DOPA PET/CT scan according to clinical, biochemical, or radiological suspicion of recurrence, while 3 were only genetically positive, with no previous symptom/sign of the disease. For all patients, biochemical analysis (plasma and/or urinary catecholamine) and results of high-resolution morphological imaging studies (CT and/or MRI) were available. Histologic/cytologic findings or imaging and biochemical follow-up were taken as gold standard in all cases. Results Seven out of 10 patients showed one or more areas of pathological 18F-DOPA accumulation. PET/CT demonstrated the presence of the disease in 4/6 patients with no increase in catecholamine levels (“biochemically silent”). Positive detection rate was 100% in SDH-D and 40% in “non-SDHD”. Analyzing per lesion, 18F-DOPA PET/CT demonstrated more lesions than anatomical imaging (16 vs. 7) especially in head and neck paragangliomas. Conclusions 18F-DOPA PET/CT seems to be the more accurate method for staging and restaging patients with SDH-mutations-related paraganglioma syndromes. 18F-DOPA is particularly useful in detecting head and neck and biochemically silent paragangliomas, and also in apparently healthy mutation-carrying people.

Metabolic and anatomic characteristics of benign and malignant adrenal masses on positron emission tomography/computed tomography: a review of literature

PET/CT with 18F-fluorodeoxyglucose (FDG) or using different radiocompounds has proven accuracy for detection of adrenal metastases in patients undergoing cancer staging. It can assist the diagnostic work-up in oncology patients by identifying distant metastases to the adrenal(s) and defining oligometastatic disease that may benefit from targeted intervention. In patients with incidentally discovered adrenal nodules, so-called adrenal “incidentaloma” FDG PET/CT is emerging as a useful test to distinguish benign from malignant etiology. Current published evidence suggests a role for FDG PET/CT in assessing the malignant potential of an adrenal lesion that has been ‘indeterminately’ categorized with unenhanced CT, adrenal protocol contrast-enhanced CT, or chemical-shift MRI. FDG PET/CT could be used to stratify patients with higher risk of malignancy for surgical intervention, while recommending surveillance for adrenal masses with low malignant potential. There are caveats for interpretation of the metabolic activity of an adrenal nodule on PET/CT that may lead to false-positive and false-negative interpretation. Adrenal lesions represent a wide spectrum of etiologies, and the typical appearances on PET/CT are still being described, therefore our goal was to summarize the current diagnostic strategies for evaluation of adrenal lesions and present metabolic and anatomic appearances of common and uncommon adrenal lesions. In spite of the emerging role of PET/CT to differentiate benign from malignant adrenal mass, especially in difficult cases, it should be emphasized that PET/CT is not needed for most patients and that many diagnostic problems can be resolved by CT and/or MR imaging.

Management of epithelial ovarian cancer from diagnosis to restaging: an overview of the role of imaging techniques with particular regard to the contribution of 18F-FDG PET/CT.

Epithelial ovarian carcinoma is a major form of cancer affecting women in the western world. The silent nature of this disease results in late presentation at an advanced stage in many patients. It is therefore important to assess the role of imaging techniques in the management of these patients. This article presents a review of the literature on the role of 18F-FDG-PET/CT in the different stages of management of epithelial ovarian cancer. Moreover, a comparison with other imaging techniques has been made and the relationship between 18F-PET/CT and the assay of serum CA-125 levels has been discussed.

Molecular Imaging of Pulmonary Nodules

OBJECTIVE Lung nodules can be benign or malignant, reflecting many possible causes, ranging from inflammatory and infectious processes to neoplasms. Incidental detection on chest x-ray or thoracic CT often requires further evaluation by imaging or invasive procedures. CONCLUSION Currently, 18F-FDG PET/CT offers both anatomic and metabolic characterization of lung nodules. Fluorine-18-thymidine, 11C-methionine, 68Ga-DOTA-somatostatin analogs, and 18F-dihydroxyphenylalanine may offer additional molecular information useful for diagnosis and treatment planning.

Positron-emission tomography in gynaecologic malignancies

IntroductionThe role of 18F-FDG PET in the management of gynaecologic malignancies remains unclear mainly due to the failure of clinicians to appreciate the significance of this imaging tool. However, this under utilisation is being actively re-addressed with a large number of reviews and studies, particularly in the last few years.Methods and ResultsPET has been shown to have high sensitivity and specificity in the evaluation of relapse and nodal disease in cervical cancer, while other uses such as staging and monitoring response to therapies being under further investigation. Similarly, promising results have been published in the use of PET in patients affected by endometrial cancer and uterine sarcomas for detecting lymph nodes metastasis and recurrent disease. In ovarian cancer, PET appears to have a great potential in staging and assessment of disease relapse. An important utility of PET in gynaecologic tumours, which is shared with a large number of other malignancies, is its value in positively changing the patients’ management.Conclusion The surge in studies using PET in gynaecological malignancies is in its early stages, and further studies are required to optimise the role of PET in these conditions.