Iranian Journal of Radiology
Volume:3 Issue: 1, Autum 2005

Nodular regenerative hyperplasia of the liver (NRHL) is characterized by hepatocellular nodules without fibrous septa between the nodules, and has been described in association with certain diseases. The NHRL should be considered in a liver mass and coexisting portal hypertension. We described the case of a 33-year-old Iranian man with NRHL in association with essential thrombocythemia.

Background/ Coronary vessel calcification is an obvious sign of atherosclerotic disease of coronary arteries. Electron beam CT scan is currently the imaging modality of choice for assessing coronary artery calcifications. However, its high cost makes it unavailable to a large number of medical centers. We carried out this study to compare the diagnostic yield of spiral CT scans as an alternative, to coronary angiography. Patients and A hundred patients suspicious of having coronary artery disease (CAD) underwent angiography as well as spiral CT scan of the heart. On CT scan, calcification of >90 Hounsfield on a surface area of >0.5 mm2, anatomically superimposed on coronary arteries were highlighted as calcified areas using the volumetric feature of the scanner. The findings were compared to angiographic results. Of 100 patients enrolled (62 males), 69 had coronary artery obstruction (>50% stenosis on angiography). Angiography was normal in the rest. Spiral CT scan had a sensitivity of 94% and a specificity of 61% for the diagnosis of coronary artery disease. The PPV and NPV were 84% and 79%, respectively. Among the coronary arteries, LAD findings had the highest sensitivity (92%) and the lowest specificity (65%) in the diagnosis of CAD. With age, spiral CT scan had more sensitivity and less specificity for CAD. Detecting calcification by spiral CT scanning could be a useful non-invasive method for diagnosis and evaluation of coronary artery stenosis.

Background/ The role of patellar tilt in the anterior knee pain is indisputable. Traditionally, the lateral patellofemoral angle of Laurin has been defined in both the axial view and CT images for measuring the tilt of patella. We present a new angle, which is independent of the morphology of patella and directly relates to clinical assessment of the tilt, which is appreciated from palpation of the edges of the patella. Patients and 38 patients with anterior knee pain and forty normal control subjects were examined using CT scan of patellofemoral joint in 15 degrees of knee flexion. The amount of lateral patellar tilt was quantitatively assessed using the lateral patellofemoral angle, as described by Laurin et al, and the newly defined patellar cortex tilt angle. This angle is subtended by the line drawn along the posterior femoral condyles and the one parallel to the subchondral bone of patellar cortex. The fifteen-degree tilt was taken as normal cut-off point for patellar cortex tilt angle in the control group. In patients, the average tilt of patella, using the patellar cortex tilt angle was 15.26 versus 7.05 in the control group. Using Student’s t test, the difference between the two means was significant (P<0.001). The sensitivity and specificity of patellar cortex tilt angle were 40 and 90 percent, respectively There was a moderate agreement between our presented test and the lateral tilt angle test (kappa=0.40, P<0.001). Our results indicate that patellar tilt can also be detected using patellar cortex tilt angle. We need more specific studies to determine the validity of the test.

A case of intracranial Rosai-Dorfman syndrome is presented that was initially diagnosed and treated as meningioma, and was complicated due to a wrong diagnosis of coexistent lung sarcoidosis. Intracranial lesions appeared as dura-based parasellar and anterior fossa enhanc-ing lesions on magnetic resonance images. Excellent result was obtained from whole brain radiotherapy, which can be used as a guideline for treating similar cases.

A 37-year-old Iranian woman presented acutely with decreased level of consciousness and bi-lateral mydriasis to the emergency ward. CT scan and MRI showed a large intracranial mass in the left frontotemporoparietal region of the cerebrum. The clinical and imaging findings were suggestive of an intracranial tumor. Frontotemporal lobectomy was performed and the resected specimen contained white caseating material. Grossly, the resected specimen was white and firm. Microscopically multiple granulomatous le-sions with epitheliod histiocytes and Langerhans giant cells and central caseation were seen, surrounded by inflammatory infiltration of plasma cells and neutrophils as well as meningeal congestion. These findings were compatible with necrotizing granulomatous encephalitis of tuberculosis. Parenchymal CNS tuberculosis with or without extra-cerebral manifestations may present as a space-occupying lesion. Because a tuberculoma is rarely suspected especially if there is atypical morphology, biopsy is required to establish the diagnosis and specific treatment

Background/ As a part of a nationwide survey to estimate population exposure to radiation from diagnostic nuclear medicine in Iran, this paper presents the pediatric population radiation exposure due to nuclear medicine examinations in Tehran. Patients and The effective dose equivalent, HE, was used to calculate the collective effective dose in pediatric patients undergoing nuclear medicine procedures, and the corre-sponding data were obtained from thirty out of thirty seven active nuclear medicine departments in Tehran. Annually about 5.26% of nuclear medicine examinations were performed on patients under 15 years of age in Tehran. The most frequent was renal examinations (38.2%), followed by thyroid (27.4%) and bone (26.7%). The annual collective HE for patients under 15 was 19.03 human-Sv, which contributed 3.96% to the collective HE for all patients. The contribution of renal, bone and thyroid examinations to the pediatric collective HE were 24.6%, 48.8% and 13.5% respectively. The mean effective dose equivalent per pediatric patient was 3.75 mSv. Among the three most frequent examinations, the bone with a relative frequency of 27.4% constituted 48.8% of the collective HE, which was the highest absorbed dose per examination. The mean effective dose per examination for patients younger than 15 years was 67.9% of the adults.

Langerhans cell histiocytosis (LCH) is a rare disorder characterized by infiltration of either single or multiple organs by S100 and CD1a positive cells. Patients with pulmonary LCH are predisposed to pneumothorax due to destructive changes in the lung parenchyma. Here, we report a case of multisystem LCH who presented at 2 months of age with simultaneous bilateral spontaneous pneumothorax.

Background/ Considering the different renal manifestations of rheumatoid arthritis (RA), we carried out this study to investigate the prevalence of renal stones in patients with RA compared to general population. Patients and From January 2000 to March 2001, 74 patients with RA and 58 healthy individuals as the control group were evaluated for kidney stones with sonography. All patients were diagnosed on the basis of 1987 criteria of American College of Rheumatology (ACR).1 In the group of patients with RA, 6 out of 74 subjects (8.1%) had renal stones. The prevalence of renal stones in the control group was 8.6% (5 out of 58 persons). The difference in the incidence of renal stones in the two groups was not statistically significant. The size of renal stones in the two groups was not significantly different. We did not find any relationship between the duration of RA or its various symptoms and the incidence of renal stones. Although RA involves kidneys and in previous studies it was mentioned that the incidence of renal stones in the patients with RA is higher than general population, we did not find any significant statistical correlation between RA and the incidence of renal stones in our study.

Backgrounds/ To evaluate the prevalence of significant carotid artery stenosis and its determining factors in candidates of coronary artery bypass graft (CABG) surgery. Patients and 1045 consecutive CABG candidates underwent carotid artery Doppler examination in a cross sectional study. The relation of age, gender, history of smoking and diabetes, as well as lipid profile to significant carotid stenosis was evaluated. In study subjects, mean age of 60.57±9.3 years, the prevalence of significant carotid stenosis (>60%) was 6.9%. In subjects older than 65 years the significant stenosis tolled to 12.5%. Over 50 years of age, female gender, hypercholesterolemia and diabetes were independent determining factors for significant carotid stenosis. Significant carotid stenosis has significantly higher prevalence among patients over 50 years of age. Cost benefit studies are recommended to revise the current evaluation protocols.