Osama Raslan

Rosai-Dorfman disease in neuroradiology: Imaging findings in a series of 10 patients

OBJECTIVE Rosai-Dorfman disease is a rare disorder characterized histologically by lymphatic sinus dilatation due to histiocyte proliferation. Our goal was to describe the CT, MRI, and (18)F-FDG (FDG) PET findings in a series of patients with this diagnosis. MATERIALS AND METHODS We retrospectively reviewed the imaging studies of 10 patients with pathologically confirmed Rosai-Dorfman disease who were treated in our institution between January 2004 and December 2007. RESULTS We found the following areas of general involvement: three intracranial, seven head and neck, and three spinal, with some patients having more than one site. Specific sites of involvement included the following: intracranial meninges, n = 2; pituitary, n = 2; lacrimal gland, n = 1; paranasal sinus, n = 3; neck lymph nodes, n = 6; salivary gland, n = 3; tonsil, n = 1; skin, n = 1; spinal meninges, n = 2; vertebral body, n = 1; and thymus, n = 1. The MRI characteristics of the involved areas were generally T1 isointense, T2 isointense, diffusion isointense to gray matter, and intensely enhancing with gadolinium chelate contrast agents. CT images generally showed the lesions were hyperdense to gray matter and intensely enhancing. FDG PET showed variable uptake, with nodal and lacrimal disease generally being FDG avid and other sites not. CONCLUSION Rosai-Dorfman disease has a protean imaging appearance but most frequently presents as neck lymphadenopathy. The disease is frequently multifocal, and a diagnosis in one area should prompt suspicion that other sites may be involved also.

Significant coronary calcification detected using contrast-enhanced computed tomography: Is it an indication for further investigation?

Background: Evaluate the significance of coronary arteries calcifications detected using contrast-enhanced chest computed tomography (CECCT) scans. Methods: A total of 145 patients who underwent both CECCT and gated stress myocardial perfusion imaging (MPI) within 2 weeks were included. The chest CT scans were reviewed for the presence of coronary artery calcium (CAC) by 2 experienced blinded readers. The degree of calcifications seen in any visualized area of the major coronary arteries was graded on a scale of 1 to 3 (1 when 0 to 4 small scattered plaques were seen, 2 when 5 or more scattered plaques were seen, and 3 when diffuse contiguous calcification were seen). The grade of CAC was correlated with the presence of MPI abnormalities. Additionally, the locations of the MPI abnormality was correlated with the CAC grade in the culprit coronary artery. Results: Of 580 major coronary arteries evaluated, 79% had grade 1 CAC, 10% had grade 2, 11% had grade 3, and 1% were inevaluable. Of the 145 patients, 33 (23%) had abnormal MPI results. Twenty-three of the patients with abnormal MPI results (70%) had more than 4 calcified plaques (CAC grade of 2 or 3) in one or more of their coronary arteries, whereas 41 of 122 patients with normal MPI results (37%) had similar CAC grades (P = 0.001). Seventeen of the 33 patients (52%) who had MPI defects also had significant CAC in the culprit coronary artery, 7 patients (21%) had significant CAC in a different coronary artery from the MPI defect territory, 8 patients (24%) had no significant CAC visualized, and in 1 patient a pacemaker wire interfered with CAC grading in the culprit coronary artery (RCA). The sensitivity, specificity, the positive, and negative predictive values of grade 2 or 3 CAC for an abnormal MPI results were 70%, 63%, 36%, and 88%, respectively. When a subgroup of patients above 60 years old with grade 3 CAC was reanalyzed, the sensitivity, specificity, the positive, and negative predictive values for an abnormal MPI results were 69%, 73%, 41%, and 90%, respectively. Conclusion: Multiple diffuse CAC as detected during the interpretation of CECCT scans in combination with advanced age is a significant finding that warrants further investigation for functionally significant CAD.

Incidental Findings on Myocardial Perfusion SPECT Images

Myocardial perfusion SPECT plays a crucial role in the diagnosis of coronary artery disease, providing a noninvasive tool to monitor ischemia and infarction. The findings can have a profound impact on diagnosis and management in these patients. However, incidental noncardiac findings on myocardial perfusion SPECT images can also affect management. These noncardiac subtleties are most often detected on the rotating raw SPECT images, which are often overlooked. The intent of this pictorial essay is to illustrate several subtle noncardiac abnormalities within nuclear cardiac imaging that can have an impact on patient management and follow-up.

Image findings of cranial nerve pathology on [18F]-2- deoxy-D-glucose (FDG) positron emission tomography with computerized tomography (PET/CT): a pictorial essay.

This article aims to increase awareness about the utility of 18F -FDG-PET/CT in the evaluation of cranial nerve (CN) pathology. We discuss the clinical implication of detecting perineural tumor spread, emphasize the primary and secondary 18F -FDG-PET/CT findings of CN pathology, and illustrate the individual 18F -FDG-PET/CT CN anatomy and pathology of 11 of the 12 CNs.

Stereoscopic Visualization of Diffusion Tensor Imaging Data: A Comparative Survey of Visualization Techniques

Diffusion tensor imaging (DTI) data has traditionally been displayed as a grayscale functional anisotropy map (GSFM) or color coded orientation map (CCOM). These methods use black and white or color with intensity values to map the complex multidimensional DTI data to a two-dimensional image. Alternative visualization techniques, such as V max maps utilize enhanced graphical representation of the principal eigenvector by means of a headless arrow on regular nonstereoscopic (VM) or stereoscopic display (VMS). A survey of clinical utility of patients with intracranial neoplasms was carried out by 8 neuroradiologists using traditional and nontraditional methods of DTI display. Pairwise comparison studies of 5 intracranial neoplasms were performed with a structured questionnaire comparing GSFM, CCOM, VM, and VMS. Six of 8 neuroradiologists favored V max maps over traditional methods of display (GSFM and CCOM). When comparing the stereoscopic (VMS) and the non-stereoscopic (VM) modes, 4 favored VMS, 2 favored VM, and 2 had no preference. In conclusion, processing and visualizing DTI data stereoscopically is technically feasible. An initial survey of users indicated that V max based display methodology with or without stereoscopic visualization seems to be preferred over traditional methods to display DTI data.

Central Nervous System Rosai–Dorfman Disease

In 1969, Rosai and Dorfman described the triad of massive cervical lymphadenopathy, expanded lymph node sinuses and characteristic histiocytes showing “emperipolesis” as a new, rare, idiopathic, nonneoplastic, lymphoproliferative disorder known as Rosai Dorfman Disease (RDD) or ‘sinus histiocytosis with massive lymphadenopathy (SHML) (Rosai and Dorfman 1969). Since then, over 750 cases have been reported in the literature (Hargett and Bassett 2005). Typically, RDD is characterized by bilateral painless cervical lymphadenopathy with fever, leukocytosis, increased erythrocyte sedimentation rate and hypergammaglobulinaemia (Chopra et al. 2006). However, in approximately 40% of cases, extranodal lesions in the skin, upper respiratory tract, orbit, testicle, soft tissue, kidney, thyroid, small bowel, breast, and bone can be found (Ruggiero et al. 2006).

Case 227: Endobronchial Carcinoid Tumor with Incidental Metastatic Breast Cancer Detected with Somatostatin Receptor Scintigraphy (111In Pentreotide)

HISTORY A 30-year-old woman with polycystic ovarian syndrome who was undergoing hormone replacement therapy presented with a 6-month history of a nonproductive cough and a 1-day history of hemoptysis (approximately 20 mL). Intravenous contrast material-enhanced (100 mL of Omnipaque 350; GE Healthcare, Princeton, NJ) computed tomographic (CT) pulmonary angiography was performed to evaluate for pulmonary embolism. On the basis of the CT pulmonary angiographic findings, chromogranin A and 5-hydroxyindoleacetic acid levels were measured and were 7 nmol/L (343 µg/L) (high) and 2.9 mg per 24 hours (15.167 µmol/d) (normal), respectively. This patient underwent bronchoscopy and biopsy. After these tests, she was referred for whole-body scintigraphy, which revealed an unexpected finding that was further investigated with fluorine 18 ((18)F) flurodeoxyglucose (FDG) positron emission tomography (PET) and CT.

18F-FDG-avid plantar nodules on true whole-body 18F-FDG PET/CT in cancer patients.

Plantar pain is a common problem endured by most adults at some point in their life that may result in considerable disability. Plantar fibromatosis is a locally invasive neoplasm, with the development of fibrous nodules on the plantar aspect of the feet, which can remain asymptomatic for years. 18F-Fluorodeoxyglucose (18F-FDG) PET/CT has been more prevalent as the imaging modality of choice for cancer patients, but the imaged field of view is often from the base of the skull to the upper thighs. Therefore, the feet are typically not included in the field. However, true whole-body imaging from the top of the skull to the bottom of the feet is performed at some institutions and can provide clinically useful findings. One such finding is the presence of 18F-FDG-avid plantar nodules. This review is intended to help clinicians become aware of these potential false-positive nodules that can affect a patient’s staging and management.

Nuclear Oncology 2: Scintigrahic Imaging

Nuclear medicine has a major role in the management of malignant tumors. With the developments towards molecular imaging and the technological advancement of scanners providing a fusion of both physiologic and anatomic imaging, it has even become a more integral part of management protocols. This role includes detection of malignant tumors, staging and restaging of the disease, early detection of recurrence, evaluation of the response to therapy, and prediction of the prognosis. Radionuclide diagnosis and therapy for tumors depend on the characteristics of tumors including increased vascularization, increased blood flow, newly proliferated capillaries with more permeable walls, increased metabolic activity of cells, increased energy demand, high density of some common antigens or several specific antigens, and several specific receptors as discussed in the previous chapter.

Sjögren syndrome complicated by mucosa-associated lymphoid tissue lymphoma and lymphocytic interstitial pneumonia

Sjögren syndrome (SS) is an autoimmune disease with exocrine glands dysfunction and multiorgan involvement. It is associated with increased risk of lymphoproliferative disorders, especially B-cell marginal zone lymphoma. While the role of F-18 Fluorodeoxyglucose position emission tomography/computed tomography (F-18 FDG PET/CT) for evaluation of lymphoma has been established, its use in patients with a chronic history of SS to evaluate for possible lymphoproliferative disorders or multiorgan involvement is limited. We present a case of chronic SS in which F-18 FDG PET/CT demonstrated FDG avid intraparotid and cervical lymph nodes pathologically proven to be mucosa-associated lymphoid tissue lymphoma. In addition, the patient had bibasilar cystic changes consistent with lymphocytic interstitial pneumonia.