MRI characterization of 124 CT-indeterminate focal hepatic lesions: evaluation of clinical utility

Objective. To evaluate the diagnostic yield of MRI performed for characterization of focal hepatic lesions that are interpreted as indeterminate on CT. Patients and methods. In a retrospective investigation, 124 indeterminate focal hepatic lesions in 96 patients were identified on CT examinations over 5 years from 1997 to 2001. All patients had MRI performed for the liver within 6 weeks of their CT examination. CT and MR images were reviewed independently by two separate groups of two radiologists. The value of MRI in characterizing these lesions was assessed. Diagnoses were confirmed based on histology, characteristic imaging features, and clinical follow-up. Results. MRI definitely characterized 73 lesions (58%) that were indeterminate on CT. MRI was accurate in 72/73 of these lesions. MRI could not definitely characterize 51 lesions (42%). Ten lesions were not visualized on MRI, and follow-up imaging confirmed that no lesion was present in eight of these cases (pseudolesions). Conclusion. MRI is valuable for the characterization of indeterminate focal hepatic lesions detected on CT.     

Neoplasms of the perivascular epithelioid cell involving the abdomen and the pelvis: cross-sectional imaging findings

Neoplasms of the perivascular epithelioid cell (PEComas) represent a recently described heterogeneous group of mesenchymal tumors characterized by the presence of specific histological, immunohistochemical, and ultrastructural findings. The PEComas encompass a family of neoplasms that include angiomyolipomas, clear cell sugar tumors, and lymphangioleiomyomatosis. The PEComas demonstrate a wide spectrum of clinicobiological behavior and imaging findings. Perivascular epithelioid cell, as the name implies, is a unique cell that is characterized by perivascular distribution and epithelioid morphology. Perivascular epithelioid cell consistently shows immunoreactivity to melanocytic and smooth muscle markers including HMB-45 and actin. Abdominopelvic PEComas are found at a variety of somatic and visceral locations including kidney, liver, pancreas, gastrointestinal tract, genitourinary tract, peritoneum, and retroperitoneum. A subset of patients with abdominopelvic PEComas manifests tuberous sclerosis complex. In this paper, we review the histological spectrum and discuss the imaging findings of the PEComas that involve the abdomen and pelvis.     

Segmental disorders of the nephron: histopathological and imaging perspective

Recent advances in molecular genetics and immunocytochemistry have clarified the cell of origin in many renal disorders. Several renal disorders are thought to involve specific segments of the nephron. Renin-secreting tumours arise from juxtaglomerular cells. Clear cell and papillary renal cell carcinoma (RCC) recapitulate the epithelium of the proximal tubules. Oncocytoma and chromophobe RCC differentiate towards Type A and Type B intercalated cells of the cortical collecting duct, respectively. Medullary collecting ducts are the target sites for the development of autosomal recessive polycystic kidney disease, collecting duct carcinoma and medullary carcinoma. Renal papillae are susceptible to unique changes such as necrosis or papillitis. The purpose of our article is threefold: to illustrate the imaging findings of renal disorders that show segmental involvement of the nephron, to describe proximal and distal nephron disorders and to correlate imaging findings of some entities with histopathological features.     

A Novel Method of Island Blocking in Whole Abdominal Radiotherapy Using a Modified Electronic Tissue Compensation Technique

Traditionally, large fields requiring island blocking used external beam radiation therapy (EBRT) with Cerrobend blocks to limit dose to the critical structures. It is laborious to construct blocks and use them on a daily basis. We present a novel technique for island blocking using a modified electronic tissue compensation (MECOMP) technique. Five patients treated at our institution were selected for this study. The study compared two planning techniques: a novel MECOMP and a conventional EBRT technique. Conventional fields were defined using anterior-posterior and posterior-anterior (PA) fields. The kidneys were contoured and an aperture cut-out block was fitted to the OAR with a 1-cm margin (OAR_CTV) and placed in the PA field. A dynamic multileaf collimation (DMLC) plan with ECOMP was developed using identical beam and blocking strategy; this tissue compensation–based fluence map was modified to deliver a “zero” dose to the CTV_OAR from the PA field. There were no significant differences in the mean, maximum, and minimum doses to the right or left kidney between the two methods. The mean, maximum, and minimum doses to the peritoneal cavity were also not significantly different. The number of monitor units (MUs) required was increased using the MECOMP (273 vs. 1152, p < 0.01). The MECOMP is effectively able to deliver DMLC-based radiotherapy, even with island blocks present. This novel use of MECOMP for whole abdominal radiotherapy should substantially reduce the labor, daily treatment time, and treatment-related errors through the elimination of cerrobend blocks.     

Cardiac Amyloidosis for the Primary Care Provider: A Practical Review to Promote Earlier Recognition of Disease

Cardiac amyloidosis is increasingly recognized as an underdiagnosed cause of heart failure. Diagnostic delays of up to 3 years from symptom onset may occur, and patients may be evaluated by more than 5 specialists prior to receiving the correct diagnosis. Newly available therapies improve clinical outcomes by preventing amyloid fibril deposition and are usually more effective in early stages of disease, making early diagnosis essential. Better awareness among primary care providers of the clinical presentation and modern treatment landscape is essential to improve timely diagnosis and early treatment of this disease. In this review, we provide practical guidance on the epidemiology, clinical manifestations, diagnostic evaluation, and treatment of transthyretin and light chain cardiac amyloidosis to promote earlier disease recognition among primary care providers.     

Retrospective analysis of missed advanced adenomas on surveillance colonoscopy

OBJECTIVE: Miss rates of large polyp/cancer during colonoscopy are reported from tertiary centers where experts do the colonoscopies. This information is important for determining surveillance intervals for repeat colonoscopy, patient safety, and malpractice issues. We evaluated retrospectively the miss rates of advanced adenomas in the setting of a GI fellowship training where most colonoscopies are done by closely supervised fellows. METHODS: We reviewed the 235 patients who had at least one repeat colonoscopy after initial polypectomy, between 1992 and 1999, at the Dayton Veterans Affairs Medical Center. Advanced adenomas were defined as polyps 10 mm or greater in size with or without a villous component or high-grade dysplasia. Data of missed advanced adenomas on 122 patients who had complete colonoscopy with satisfactory preparation and the excluded patients are reported. RESULTS: Four advanced adenomas (one had intramucosal cancer) on second colonoscopy and two advanced adenomas on third colonoscopy were missed. The miss rate of advanced adenoma for 232 patients was 1.7%, and the miss rate for the 122 patients with complete colonoscopy and satisfactory colon preparation was 2.5% and 3.3% on second and third repeat colonoscopy, respectively. No cancer was missed. CONCLUSIONS: The present study shows an advanced polyp miss rate that is comparable with other studies even in a fellowship training setting. Prospective studies with tandem surveillance colonoscopy are needed to confirm our findings.