Clinical significance of incidental focal colorectal 18F‐fluorodeoxyglucose uptake: our experience and a review of the literature

Aim The aims of the present study were: (i) to evaluate the focal incidental colorectal uptake of ¹⁸F‐fluorodeoxyglucose ([¹⁸F]FDG) and to correlate it with colonoscopy and histological findings; (ii) to evaluate the relationship between the presence/absence of neoplastic disease and clinical data and the anatomical site of [¹⁸F]FDG uptake; and (iii) to compare our results with those reported for incidental colorectal uptake of [¹⁸F]FDG in the literature and those obtained from various screening programmes for colorectal cancer. Method The database of 6000 patients referred for [¹⁸F]FDG positron emission tomography/computed tomography (PET‐CT) to our centre was retrospectively reviewed for incidental colorectal uptake of [¹⁸F]FDG. Patients with focal uptake were selected and the aetiology of PET findings was verified with a subsequent colonoscopy and histopathological analysis when available. Results Incidental colorectal uptake of [¹⁸F]FDG was seen in 144 (2.4%) patients, of whom 64 (1.1%) had focal uptake; 48 out of these 64 patients underwent colonoscopy, which showed malignant tumours in 12 (25%), premalignant lesions in 19 (40%), non‐neoplastic lesions in six (12%) and lesions not confirmed by colonoscopy in 11 (23%). Our data agreed with previously published data. Statistical analysis did not show any significant relationship between the presence/absence of neoplastic disease and patient sex or age, type of primary disease and anatomical site of [¹⁸F]FDG uptake. Comparing our data with various screening programmes, a significant difference was found only with series in which colonoscopy was performed in patients at high risk for colorectal cancer. Conclusion Focal incidental colorectal uptake of [¹⁸F]FDG is observed in about 1% of PET/CT studies and carries a high risk of neoplastic disease. A PET‐CT report should suggest colonoscopy when abnormal findings are reported.     

Whole-Body [18F]FDG PET in the Management of Metastatic Brain Tumours

Summary Background To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission tomography (PET) using [¹⁸F]FDG was performed in 20 consecutive patients. Methods  All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively, a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [¹⁸F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods. Results  Metastatic brain tumours were diagnosed on whole-body [¹⁸F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional work-up also detected primary lesions which on whole-body [¹⁸F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [¹⁸F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions. In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma, Ewing's sarcoma, and cavernous angioma.  Patients felt no discomfort during the whole-body [¹⁸F]FDG PET procedure and there were no complications. The false negative rate in [¹⁸F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [¹⁸F]FDG PET or conventional work-up. Conclusion  It is suggested that whole-body [¹⁸F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering or needing to be differentiated from a metastatic brain tumour.     

Positron Emission Tomography in Clinical Islet Transplantation

The fate of islets in clinical transplantation is unclear. To elude on this positron emission tomography combined with computed tomography (PET/CT) was performed for 60 min during islet transplantation in five patients receiving six transplants. A fraction of the islets (23%) were labeled with 18F‐fluorodeoxyglucose ([¹⁸F]FDG) and carefully mixed with unlabeled islets just prior to intraportal transplantation. The peak radioactivity concentration in the liver was found at 19 min after start of islet infusion and corresponded to only 75% of what was expected, indicating that islets are lost during the transplantation procedure. No accumulation of radioactivity was found in the lungs. A nonphysiological peak of C‐peptide was found in plasma during and immediately after transplantation in all subjects. Distribution in the liver was heterogeneous with wide variations in location and concentration. Islets found in areas with concentrations of >400 IEQ/cc liver tissue varied between 1% and 32% of the graft in different subjects. No side effects attributed to the PET/CT procedure were found. Clinical outcome in all patients was comparable to that previously observed indicating that the [¹⁸F]FDG labeling procedure did not harm the islets. The technique has potential to be used to assess approaches to enhance islet survival and engraftment in clinical transplantation.     

Update on positron emission tomography for imaging of prostate cancer

Prostate cancer is the most common non‐cutaneous malignancy among men in the Western world, and continues to be a major health problem. Imaging has recently become more important in the clinical management of prostate cancer patients, including diagnosis, staging, choice of optimal treatment strategy, treatment follow up and restaging. Positron emission tomography, a functional and molecular imaging technique, has opened a new field in clinical oncological imaging. The most common positron emission tomography radiotracer, ¹⁸F‐fluorodeoxyglucose, has been limited in imaging of prostate cancer. Recently, however, other positron emission tomography tracers, such as ¹¹C‐acetate and ¹¹C‐ or ¹⁸F‐choline, have shown promising results. In the present review article, we overview the potential and current use of positron emission tomography or positron emission tomography/computed tomography imaging employing the four most commonly used positron emission tomography radiotracers, ¹⁸F‐fluorodeoxyglucose, ¹¹C‐acetate and ¹¹C‐ or ¹⁸F‐choline, for imaging evaluation of prostate cancer.     

Segmentectomy versus wedge resection for radiological solid predominant and low metabolic non-small cell lung cancer

Open in a separate window OBJECTIVESThe prognosis of segmentectomy and wedge resection for solid predominant early-stage non-small cell lung cancer with low metabolic activity is unclear.METHODSThis study aimed to assess patients who underwent segmentectomy or wedge resection with curative intent for clinically node-negative non-small cell lung cancer presenting as a solid predominant tumour (consolidation tumour ratio >50%) with a whole size ≤3 cm and [18F]-fluoro-2-deoxy-D-glucose accumulation weaker than that of the mediastinum tissue (Deauville score, 1 or 2) on positron emission tomography/computed tomography. The cumulative incidence of recurrence (CIR) was compared using the Gray method, and the predictive factor of CIR was analysed using the Fine and Gray method.RESULTSOf 140 patients included in this study, 93 (66.4%) underwent segmentectomy and 47 (33.6%) underwent wedge resection. No significant difference in the clinical stage was found between the 2 groups. The CIR was higher with wedge resection than with segmentectomy (P = 0.004). Recurrence after wedge resection was noted in 4 (8.5%) patients, 2 of whom had a recurrent site containing lung parenchyma of the preserved lobe and hilum lymph node, which would have been resected if segmentectomy had been performed. In the multivariable analysis for CIR using inverse probability of treatment weighting and the procedure, wedge resection was a significantly worse predictive factor (hazard ratio, 12.280; P = 0.025).CONCLUSIONSSegmentectomy rather than wedge resection should be considered for solid predominant, small-size non-small cell lung cancer even if [18F]-fluoro-2-deoxy-D-glucose accumulation is low.     

Peritoneal recurrence of colon cancer detected by positron emission tomography: Report of a case

Increased glucose metabolism has been reported to occur in association with colorectal cancer. As positron emission tomography (PET) using [¹⁸F]fluorodeoxyglucose is able to depict hypermetabolic sites, it can therefore be used to detect colorectal cancer. A 69-year-old male patient with a recurrent solitary liver metastasis from colon cancer underwent whole-body PET which revealed high [¹⁸F]fluorodeoxyglucose uptake in the lesion. Furthermore, PET revealed peritoneal metastases that had not been detected by conventional imaging methods. Consequently, PET proved useful in helping us to avoid performing unnecessary treatment for the liver metastasis. Although it is uncertain whether early identification of recurrence can prolong survival, it may help to prevent unnecessary treatments being carried out. Thus, the application of PET in carefully selected patients could be beneficial to the management of recurrent colorectal cancer.     

Clinical value of whole body fluorine‐18 fluorodeoxyglucose positron emission tomography/computed tomography in the detection of metastatic bladder cancer

Objectives: To investigate the value of whole‐body fluorine‐18 2‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography/computed tomography for the detection of metastatic bladder cancer. Methods: From December 2006 to August 2010, 60 bladder cancer patients (median age 60.5 years old, range 32–96) underwent whole body positron emission tomography/computed tomography positron emission tomography/computed tomography. The diagnostic accuracy was assessed by performing both organ‐based and patient‐based analyses. Identified lesions were further studied by biopsy or clinically followed for at least 6 months. Results: One hundred and thirty‐four suspicious lesions were identified. Among them, 4 primary cancers (2 pancreatic cancers, 1 colonic and 1 nasopharyngeal cancer) were incidentally detected, and the patients could be treated on time. For the remaining 130 lesions, positron emission tomography/computed tomography detected 118 true positive lesions (sensitivity = 95.9%). On the patient‐based analysis, the overall sensitivity and specificity resulted to be 87.1% and 89.7%, respectively. There was no difference of sensitivity and specificity in patients with or without adjuvant treatment in terms of detection of metastatic sites by positron emission tomography/computed tomography. Compared with conventional imaging modality, positron emission tomography/computed tomography correctly changed the management in 15 patients (25.0%). Conclusions: Positron emission tomography/computed tomography has excellent sensitivity and specificity in the detection of metastatic bladder cancer and it provides additional diagnostic information compared to standard imaging techniques.     

Congenital hyperinsulinism - a review of the disorder and a discussion of the anesthesia management

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infants and children. In most affected infants, CHI is caused by a specific genetic defect that results in the altered expression of pancreatic beta cells causing unregulated oversecretion of insulin. Infants with CHI may have either focal or diffuse abnormalities of the pancreatic beta-cells. Both forms of CHI manifest as hypoglycemia, usually in the early newborn period. Focal disease can be treated effectively with surgical resection of the affected area, resulting in a total cure or rendering the patient amenable to medical management. Most children with diffuse disease are unresponsive to medical therapy, and require near-total pancreatectomy. At The Children's Hospital of Philadelphia, we have developed a multidisciplinary program for diagnosis and treatment of CHI. Anesthesiologists have played an integral role in the perioperative care of these infants, which includes diagnostic procedures, partial or near-total pancreatectomy, and postoperative pain management. In this review, we describe the clinical features, diagnostic methods and anesthetic concerns in children with CHI.