Biomedical subjects

Rodney Reznek

Publications and source records attributed to Rodney Reznek.

6 recordsLinked to original sources

PubMed2006

Commonly used imaging techniques for diagnosis and staging.

Imaging plays a vital role in the management of patients with cancer. Not only is it important for diagnosis, indicating sites of abnormality, and guiding biopsies, but it is also crucial in assessing disease extent and thereby determining treatment. In this review, conventional imaging techniques such as ultrasound, computed tomography, magnetic resonance imaging, and [18F]fluorodeoxyglucose-positron emission tomography are described, with attention to their mechanisms of action, and their strengths and weaknesses in diagnosis and staging of tumors. New developments are addressed and radiation safety issues are highlighted. In addition, we describe current and expected future uses of imaging techniques in oncology. Given that each technique has its inherent strengths and weaknesses, the combination of the methods will result in improved diagnosis, staging, and treatment prediction and monitoring.

Contrast Media↗

PubMed2006

Biochemical diagnosis and localization of pheochromocytoma: can we reach a consensus?

Pheochromocytomas can have a highly variable presentation, making diagnosis challenging. To think of the tumor represents the crucial initial step, but establishing the diagnosis requires biochemical evidence of excessive catecholamine production and imaging studies to localize the source. Currently, however, there exist no generally agreed upon guidelines based on which tests and testing algorithms should be used to confirm and locate or exclude a suspected pheochromocytoma. Choice of biochemical tests and imaging studies instead usually depends on institutional experience. At the First International Symposium on Pheochromocytoma (ISP2005), held in Bethesda in October 2005, a panel of experts and patient representatives discussed current problems and available options for tumor diagnosis and localization and formulated recommendations, which were subsequently agreed upon by those in attendance at the meeting. This article summarizes the discussion and recommendations derived from that session.

Adrenal Gland Neoplasms↗

PubMed2004

Virtual cystoscopy from computed tomography: a pilot study.

OBJECTIVE: To assess the feasibility of virtual cystoscopy reconstructed from helical computed tomography (CT) obtained using an intravenous contrast agent, and to correlate the findings with flexible (FC) and rigid cystoscopy (RC) in patients with bladder tumours. PATIENTS AND METHODS: Eighteen patients (16 men and two women, mean age 72 years, range 59-80) with haematuria and found to have a bladder tumour on FC were included in a pilot study. Contrast-enhanced helical CT scans were taken and based on these datasets, virtual cystoscopy (VC) images were reconstructed by a radiologist unaware of the findings at cystoscopy. All patients had RC and a biopsy taken. The VC images were compared with the findings from FC and RC. RESULTS: At FC, VC and RC, 32, 34 and 36 lesions were identified, respectively; 33 (92%) of the abnormal lesions at RC were correctly identified at VC. At VC, all lesions of >4 mm were identified but only one of three <4 mm was seen. There were two false-positive finding at VC; VC correctly identified 17 (94%) of 18 abnormal bladders. Only 25% of the ureteric orifices were seen. Carcinoma in situ and urethral tumours were not visualized. CONCLUSION: CT-based VC has a high sensitivity for detecting bladder lesions and is comparable with FC; it may have a potential role as a single imaging tool for haematuria. Further larger studies are required to assess its clinical role.

Aged↗

PubMed2004

Recent advances in radiological and radionuclide imaging and therapy of neuroendocrine tumours.

Neuroendocrine tumours (NETs) constitute a heterogeneous group of tumours that are able to express cell membrane neuroamine uptake mechanisms and/or specific receptors, such as somatostatin receptors, which can be of great value in the localization and treatment of these tumours. Scintigraphy with (111)In-pentetreotide has become one of the most important imaging investigations in the initial identification and staging of gastro-enteropancreatic (GEP) tumours, whereas helical computed tomography (CT), magnetic resonance imaging (MRI), endoscopic and/or peri-operative ultrasonography are used for the precise localization of GEPs and in monitoring their response to treatment. Scintigraphy with (123)I-MIBG (meta-iodobenzylguanidine) is sensitive in the identification of chromaffin cell tumours, although scintigraphy with (111)In-pentetreotide may also have a role in the localization of malignant chromaffin cell tumours and medullary thyroid carcinoma; for further localization and monitoring of the response to treatment both CT and MRI are used with high diagnostic accuracy. More recently, positron emission tomography (PET) scanning is being increasingly used for the localization of NETs, particularly when other imaging modalities have failed, although its precise role and utility remain to be defined. Surgery is still the usual initial therapeutic, and only curative, modality of choice; however, the majority of NETs will require further treatment with somatostatin analogues and/or interferon; chemotherapy may be used for progressive and highly aggressive NETs, but its role has not been clearly defined. For those NETs that demonstrate uptake to a diagnostic scan with (123)I-MIBG or (111)In-octreotide, therapy with radionuclides such as (131)I-MIBG or (111)In/(90)Y-octreotide or other isotopes, presents a further evolving therapeutic modality.

Carcinoid Tumor↗

PubMed2003

Stepwise progression of familial adenomatous polyposis-associated desmoid precursor lesions demonstrated by a novel CT scoring system.

INTRODUCTION: Desmoids are rare, locally aggressive but nonmetastasizing clonal proliferations of fibroblasts that occur both sporadically and in association with familial adenomatous polyposis. Most occur in intra-abdominal sites, where they may lead to major morbidity and mortality. A proposed desmoid precursor lesion occurs in the mesentery of one-third of patients with familial adenomatous polyposis, and postoperative mesenteric fibromatosis has been identified in 20 percent of such patients. True desmoids occur in 10 percent, which suggests a model of development in which the phenotype becomes increasingly severe in a manner analogous to the adenoma-carcinoma sequence. This work aimed to confirm such a progression. METHODS: A five-point CT scoring system for mesenteric fibromatosis and desmoids was devised and validated, and in doing so, their incidence was observed. In the second part of the study, seven patients known to have a precursor lesion underwent abdominal CT a median of 27.5 months after the surgery that identified the lesion. Scans were assessed by the scoring system and compared with those of a matched control group of familial adenomatous polyposis patients. RESULTS: The CT scoring system was reliable and reproducible. Of 103 scans of asymptomatic patients with familial adenomatous polyposis, mesenteric fibromatosis and desmoid tumors were identified in 21 and 2 percent, respectively. In the follow-up of patients with desmoid precursor lesions, those in the precursor lesion group had a significantly greater degree of mesenteric fibromatosis and desmoid formation than their corresponding controls (P = 0.009, Mann-Whitney U test). CONCLUSION: A reliable CT scoring system for mesenteric fibromatosis and desmoid tumors in familial adenomatous polyposis is presented. Results with this system provide further evidence for a stepwise progression in the development of desmoids.

Adenomatous Polyposis Coli↗

PubMed2002

Dynamic magnetic resonance imaging evaluation of the structural and functional results of postanal repair for neuropathic fecal incontinence.

PURPOSE: The aim of this study was to determine whether dynamic magnetic resonance imaging of the pelvic floor can discriminate between patients who improve after postanal repair for neurogenic fecal incontinence and those who remain symptomatic. METHODS: Pelvic floor measurements obtained during dynamic magnetic resonance imaging in eight females whose anal incontinence had improved after postanal repair were compared with those from nine females who remained symptomatic. All subjects also underwent standard anorectal physiology testing. RESULTS: There was no significant difference between groups with respect to any measurement of anterior or middle pelvic floor compartments. Additionally, there was no difference in posterior pelvic floor configuration when symptomatic patients were compared with those who had improved. However, dynamic magnetic resonance measurements revealed patients who remained symptomatic had significantly greater posterior pelvic floor weakness. Anorectal physiology was unable to differentiate between groups. CONCLUSIONS: There is no difference in static pelvic floor measurements when subjects remaining symptomatic after postanal repair are compared with those who have improved. In contrast, dynamic measurements may be able to predict failure in those who demonstrate excessive posterior pelvic floor mobility.

Adult↗