Fahmid U. Chowdhury

Prevalence of, and predictors of, bile acid malabsorption in outpatients with chronic diarrhea.

Background  Many physicians do not consider the diagnosis of bile acid malabsorption in patients with chronic diarrhea, or do not have access to testing. We examined yield of 23‐seleno‐25‐homo‐tauro‐cholic acid (SeHCAT) scanning in chronic diarrhea patients, and attempted to identify predictors of a positive test.

Clinical impact of FDG PET-CT in patients with potentially operable metastatic colorectal cancer

AIM To assess the clinical impact of 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography-computed tomography (PET-CT) in patients with potentially resectable metastatic colorectal cancer. MATERIALS AND METHODS One hundred and two patients with potentially resectable metastatic colorectal cancer underwent FDG PET-CT in addition to conventional imaging over an 18-month period. The findings were compared to conventional imaging, with histological or clinico-radiological validation. The impact on subsequent management was evaluated using information from clinico-radiological databases. RESULTS Of 102 patients (mean age 67 years, range 27-85 years), 94 had liver, five had isolated lung, and three had limited peritoneal metastases. In 31 patients (30%) PET-CT had a major impact on subsequent management, by correctly clarifying indeterminate lesions on conventional imaging as inoperable metastatic disease in 16 patients, detecting previously unsuspected metastatic disease in nine patients, identifying occult second primary tumours in three patients, and correctly down-staging three patients. PET-CT had a minor impact in 12 patients (12%), no impact in 49 cases (48%), and a potentially negative impact in 10 cases (10%). Following PET-CT, 36 (35%) patients were no longer considered for surgery. Of those remaining operative 45 of 66 (68%) underwent potentially curative metastatic surgery. In this cohort PET-CT saved 16 futile laparotomies. CONCLUSION FDG PET-CT has a valuable role in selected patients with metastatic colorectal cancer by improving staging accuracy and characterizing indeterminate lesions and helps triage patients to the appropriate treatment.

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

Integrated positron emission tomography/CT (PET/CT) with 2-[18F]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.

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.

Hybrid SPECT/CT: the end of “unclear” medicine

The emergence of hybrid imaging, combining anatomical computed tomography (CT) and functional scintigraphic imaging has increased the armoury of techniques available to image disease. Single photon emission computed tomography/CT (SPECT/CT) is a dual modality technique which increases the sensitivity and specificity of existing radionuclide imaging and helps characterise equivocal lesions detected by other imaging methods. In addition to the many established clinical applications for SPECT/CT, there are new clinical uses emerging in a spectrum of benign and malignant diseases. In this article, we will discuss the established and emerging uses of hybrid SPECT/CT and illustrate the incremental value of the technique in a variety of clinical applications.

BCG-induced granulomatous prostatitis--an incidental finding on FDG PET-CT.

We present a case of granulomatous prostatitis that presented in a rare way as an incidentally discovered focus of increased FDG activity within the prostate on PET-CT in a patient who had previously undergone intravesical bacille Calmette-Guérin treatment for bladder cancer. FDG uptake is commonly discovered in organs distant from the region of primary interest on PET-CT and so it is important to be aware of the potential causes of this.

PET/CT staging and response evaluation of post-transplantation lymphoproliferative disease (PTLD).

A 40-year-old man presented with nonspecific chest pain 14 months following a cadaveric renal transplant for diabetic nephropathy. He was on immunosuppressive therapy with tacrolimus. Computed tomography (CT) of the chest demonstrated a destructive rib lesion with a large soft tissue component. Core biopsy confirmed a diagnosis of monomorphic posttransplantation lymphoproliferative disease strongly positive for EpsteinBarr virus. Staging fluorodeoxyglucose positron emission tomography (PET)/CT detected hypermetabolic osseous lesions, involvement of several nodal groups, and focal uptake within the liver. After reduction of immunosuppression, a follow-up PET/CT scan showed complete metabolic remission. This case highlights the utility of fluorodeoxyglucose PET/CT in the staging and response evaluation of post-transplantation lymphoproliferative disease.

Neuroendocrine tumours of the head and neck: anatomical, functional and molecular imaging and contemporary management

Abstract Neuroendocrine tumours (NETs) of the head and neck are rare neoplasms and can be of epithelial or non-epithelial differentiation. Although the natural history of NETs is variable, it is crucial to establish an early diagnosis of these tumours as they can be potentially curable. Conventional anatomical imaging and functional imaging using radionuclide scintigraphy and positron emission tomography/computed tomography can be complementary for the diagnosis, staging and monitoring of treatment response. This article describes and illustrates the imaging features of head and neck NETs, discusses the potential future role of novel positron-emitting tracers that are emerging into clinical practice and reviews contemporary management of these tumours. Familiarity with the choice of imaging techniques and the variety of imaging patterns and treatment options should help guide radiologists in the management of this rare but important subgroup of head and neck neoplasms.

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.

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.