High Prevalence of Idiopathic Bile Acid Diarrhea Among Patients With Diarrhea-Predominant Irritable Bowel Syndrome Based on Rome III Criteria.

BACKGROUND & AIMS: Some studies have found that patients with idiopathic bile acid diarrhea (BAD) present with symptoms of diarrhea-predominant irritable bowel syndrome (D-IBS). However, these studies either were retrospective, did not define D-IBS according to current criteria, or included patients with chronic functional diarrhea. We performed a prospective study of the prevalence of idiopathic BAD in consecutive patients fulfilling the Rome III criteria for D-IBS. METHODS: We analyzed data from 118 consecutive adult patients who fulfilled the Rome III criteria for D-IBS (mean age, 41.7 y; 72.9% female), seen at 2 gastroenterology clinics in the United Kingdom. We excluded patients with risk factors for BAD (previous history of cholecystectomy, terminal ileal Crohn's disease, terminal ileal resection or right hemicolectomy, pelvic or abdominal radiotherapy, celiac disease, or microscopic colitis). Participants completed questionnaires at baseline (on demographics, hospital anxiety, somatization, and depression, as well as the patient health questionnaire-12 and the Short Form-36), and then received the (75)selenium homocholic acid taurine retention test. Retention of (75)selenium homocholic acid taurine 7 days after administration was used to identify patients with idiopathic BAD (mild BAD, 10%-14.9%; moderate BAD, 5.1%-9.9%; and severe BAD, ≤5%). RESULTS: Twenty-eight patients were found to have BAD (23.7% of total), with similar percentages at each study site (25.3% and 20%; P = .54). Eight patients had mild BAD (28.6%), 8 patients had moderate BAD (28.6%), and 12 patients had severe BAD (42.8%). There was no statistical difference in age, sex, depression, patient health questionnaire-12 responses, or SF-36 scores between individuals with vs without BAD. However, patients with BAD had a higher mean body mass index than patients without BAD (31.6 vs 26.4; P = .003). Physical activity (based on the Short Form-36) was significantly lower in subjects with moderate (43.8) or severe BAD (41.7), compared with patients with mild BAD (87.5) (P = .046). CONCLUSIONS: Almost 25% of patients presenting with D-IBS have idiopathic BAD; most cases are moderate to severe. Guidelines should advocate testing to exclude BAD before patients are diagnosed with D-IBS.

[18F]FDG PET/CT imaging of colorectal cancer: a pictorial review.

Integrated positron emission tomography/CT (PET/CT) with 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) is a hybrid imaging modality which has recently become established in the staging, restaging and therapy response assessment of oncology patients. FDG PET/CT has several recognised applications in colorectal cancer (CRC) imaging including preoperative evaluation of apparently limited metastatic disease, detection of disease recurrence, clarification of equivocal lesions at initial staging, investigation of unexplained rising tumour markers, and incidental detection of occult primary colonic tumours. With a constantly advancing body of evidence and increasing availability, applications of PET/CT in CRC are likely to emerge in therapy response assessment, radiotherapy planning, use of novel tracers and 'one-stop' imaging techniques such as iodinated contrast-enhanced PET/CT. With the use of illustrative clinical examples, this article reviews the utility of FDG PET/CT in the management of CRC, discussing its role and limitations in the multimodality imaging of these patients.

Prevalence of, and predictors of, bile acid diarrhea in outpatients with chronic diarrhea: A follow-up study.

BACKGROUND: 23-seleno-25-homo-tauro-cholic acid (SeHCAT) scanning to rule out bile acid diarrhea (BAD) in patients with chronic diarrhea has a high yield. Our previous study showed that patients with terminal ileal (TI) Crohn's disease, TI resection, or cholecystectomy were highly likely to have an abnormal scan. As a result, we encouraged clinicians to use a therapeutic trial of a bile acid sequestrant in these patients, instead of scanning. This may have reduced diagnostic yield of the test, so we examined this issue, as well as factors predicting an abnormal scan, in a large cohort of patients referred subsequently. METHODS: We retrospectively identified 1,071 consecutive patients with chronic diarrhea undergoing SeHCAT scanning at Leeds Teaching Hospitals Trust from 2012 to 2016. We reviewed electronic patient records to obtain information on presenting gastrointestinal symptoms and any proposed risk factors for BAD. BAD was categorized according to subtype and severity. KEY RESULTS: As expected, indications for scanning changed between 2012 and 2016, with a significant reduction in referrals with TI Crohn's disease or resection year-on-year (P < 0.001). Despite this, 457 (42.7%) patients had BAD and there was no downward trend in yield of SeHCAT during the 5 year period (P = 0.39). Overall, 51.6% had type II BAD, 36.1% type III, and 12.3% type I. BAD was mild in 31.7%, moderate in 34.4%, and severe in 33.9%. In total, 653 (61.0%) patients had no known risk factors, other than chronic diarrhea, but 233 (35.7%) of these individuals had BAD, and in 143 (61.4%), this was moderate or severe. CONCLUSIONS AND INFERENCES: Despite reduced referrals for SeHCAT scanning in those with clear risk factors for BAD, the yield remained > 40%. One-third of those without known risk factors had BAD.

Clinical utility of hybrid SPECT-CT in endocrine neoplasia.

OBJECTIVE: Imaging of endocrine neoplasms often involves a combination of anatomic and functional techniques including sonography, CT, MRI, and scintigraphy. Recent technologic advances have enabled hybrid imaging using SPECT-CT, which combines anatomic and functional techniques to allow accurate localization of tumors, increased detection of recurrent and metastatic disease, and exclusion of physiologic uptake. CONCLUSION: SPECT-CT provides improved specificity and diagnostic confidence helping to guide conventional management and assess suitability for targeted radionuclide therapy.

Indium-111 pentetreotide uptake within cerebellar hemangioblastoma in von Hippel-lindau syndrome.

A 38-year-old woman with known von Hippel-Lindau syndrome underwent In-111 pentetreotide (OctreoScan) scintigraphy to evaluate a suspected pancreatic neuroendocrine tumor. The patient had undergone surgical resection of a left adrenal pheochromocytoma and a large right cerebellar hemangioblastoma several years previously. Although there was no evidence for recurrence of pheochromocytoma and no uptake within the pancreatic lesion, there was focal tracer accumulation within the left cerebellar hemisphere. MR imaging of the brain confirmed the presence of recurrent hemangioblastoma in the left cerebellum.

18F-FDG PET/CT Imaging of Necrotizing Crescentic Glomerulonephritis With Anti-Glomerular Basement Membrane Disease.

A 30-year-old woman presented with lethargy, night sweats, and fever with raised inflammatory markers. Anti-neutrophil cytoplasmic antibody was negative. Abdominopelvic CT was unremarkable. Subsequently, she underwent FDG PET/CT showing globally enlarged kidneys with diffuse hypermetabolic activity within the renal parenchyma bilaterally. Renal biopsies showed morphologic features of an active necrotizing crescentic glomerulonephritis, which was confirmed clinically and treated. This case demonstrates the role that FDG PET/CT can play in inflammatory conditions, such as glomerulonephritis, where it may be clinically useful when the presentation is atypical.

Evaluation of noise equivalent count parameters as indicators of adult whole-body FDG-PET image quality.

OBJECTIVES: The aim of this study was to assess variation of qualitative and quantitative PET/CT image quality parameters with acquisition time, injection activity and body mass for a representative group of adults undergoing whole-body PET/CT imaging. METHODS: PET scan data from sixty patients were reconstructed with a scan time of 1, 2 and 3 min/bed position. These images were visually scored and three quantitative parameters were calculated: noise equivalent counts per axial length (NECpatient), noise equivalent count density (NECdensity) and liver signal to noise ratio (liver SNR). The ability of the three quantitative parameters to discriminate qualitative image quality was assessed using ROC analysis. RESULTS: The quantitative parameters were shown to discriminate images of good/excellent quality from those of poorer image quality with a high degree of accuracy (ROC area >0.9); further, NECpatient had significantly higher discrimination than either NECdensity or liver SNR (ROC area = 0.97). CONCLUSIONS: NECpatient, NECdensity and liver SNR all have high discrimination for qualitatively assessed PET image quality. NECpatient in particular is an effective objective indicator of patient image quality, which will help to assess and standardise scan protocols for purposes such as multi-centre research trials.

Clinical impact of FDG PET-CT on management decisions for patients with primary biliary tumours.

OBJECTIVES: To assess the impact on clinical management of introducing (18)F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)-computed tomography (CT) in to the work-up of patients with primary and recurrent biliary malignancy. METHODS: Consecutive patients with primary biliary tumours undergoing FDG PET-CT at a single large tertiary referral centre between November 2007 and September 2010 were retrospectively analysed. Findings on FDG PET-CT compared with CT/magnetic resonance imaging (MRI) and impact on subsequent patient management were evaluated. Impact was divided into: (1) major-detection of occult disease or characterisation of indeterminate lesion(s) on CT/MRI; (2) minor-confirmation of suspected metastases seen on CT/MRI; (3) no impact. RESULTS: One hundred and eleven patients underwent 118 FDG PET-CT scans, including 30 with suspected gallbladder carcinoma and 81 with cholangiocarcinoma. Eighty-nine scans were performed for initial staging, five for restaging following neoadjuvant chemotherapy and 24 for suspected disease recurrence. In 33 cases (28 %), FDG PET-CT had a major impact on subsequent patient management (39 % gallbladder carcinoma, 26 % intrahepatic cholangiocarcinoma and 21 % extrahepatic cholangiocarcinoma). FDG PET-CT had a minor impact in 20 cases (17 %) and no impact in 65 cases (55 %). CONCLUSIONS: By detecting occult metastatic disease and characterising indeterminate lesions, FDG PET-CT can have a major influence on clinical decision-making in primary and recurrent biliary malignancy.

F-18 FDG PET/CT imaging of follicular dendritic cell sarcoma of the mediastinum.

A 52-year-old female smoker presenting with unexplained weight loss underwent CT and FDG PET/CT imaging, which demonstrated an extremely hypermetabolic mediastinal mass with calcification, necrosis, and features of local invasiveness. Mediastinoscopy and biopsy were followed by successful surgical resection of an encapsulated mass showing the typical histologic features of follicular dendritic cell sarcoma (FDCS). FDCS of the mediastinum is a rare neoplasm arising from accessory cells of the immune system. Integrated FDG PET/CT of mediastinal FDCS highlights the importance of histologic assessment of mediastinal tumors that may seem unresectable on initial imaging.

Less commonly used and emerging clinical applications of SPECT-CT in benign and malignant disease.

The emergence of hybrid imaging, combining anatomical computed tomography (CT) and functional single-photon emission computed tomography (SPECT), has greatly expanded the armoury available to image disease. Integrated SPECT-CT is a dual-modality technique, which improves the sensitivity and specificity of existing radionuclide studies and enables characterization of equivocal findings detected by conventional imaging. There is a wide range of established and emerging clinical applications for SPECT-CT, which were reviewed in detail at a symposium organized by the British Institute of Radiology in March 2012. A series of articles were commissioned as an adjunct to the symposium and to raise awareness of the clinical utility of this technique. The focus of this article is on less commonly used and emerging clinical applications of hybrid SPECT-CT in a spectrum of benign and malignant conditions. The article will illustrate the incremental value of the technique in a variety of clinical applications.

The Impact of (18)F-FDG PET CT Prior to Chemoradiotherapy for Stage III/IV Head and Neck Squamous Cell Carcinoma.

Introduction. To determine the value of a FDG-PET-CT scan in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) prior to chemoradiotherapy. Materials and Methods. Consecutive patients with stage III or IV HNSCC who had undergone a staging FDG-PET-CT scan prior to chemoradiotherapy between August 2008 and April 2011 were included. Clinical details and conventional imaging (CT and/or MRI) were, retrospectively, reviewed, a TNM stage was assigned, and levels of cervical lymph node involvement were documented. This process was repeated with the addition of FDG-PET-CT. Radiotherapy plans were reviewed for patients with an alteration identified on TNM staging and/or nodal level identification with FDG-PET-CT and potential alterations in radiotherapy planning were documented. Results. 55 patients were included in the analysis. FDG-PET-CT altered the TNM stage in 17/55 (31%) of patients, upstaging disease in 11 (20%) and downstaging in 6 (11%); distant metastases were identified by FDG-PET-CT in 1 (2%) patient. FDG-PET-CT altered the lymph node levels identified in 22 patients (40%), upclassifying disease in 16 (29%) and downclassifying in 6 (11%). Radiotherapy plans were judged retrospectively to have been altered by FDG-PET-CT in 10 patients (18%). Conclusions. The use of FDG-PET-CT potentially impacts upon both treatment decisions and radiotherapy planning.