Risk factors related to the size and volume of femoral artery pseudoaneurysm after catheter angiography: a single-center study

Background/aim: Evaluate the risk factors associated with pseudoaneurysms' development after the percutaneous interventional procedures performed by cardiology, interventional radiology (IR), and the other clinics. Materials and methods: We retrospectively analyzed the ultrasound scans in the hospital database and picture archiving system (PACS) and enrolled a total of 132 patients during the period from October 2015 and December 2019. We evaluated the maximum diameter and volume of the pseudoaneurysm with the patient and procedure-related factors with univariate analysis. Results: We found that the patients with hypertension and without peripheric artery disease (PAD) had greater sac diameter (p = 0.010 and p = 0.016) and increased sac volume (p = 0.029 and p = 0.007). However, the sac volume increased in patients with diabetes than those without (p = 0.003). Both the increased maximum diameter and the volume of the pseudoaneurysm sac were in the patients in whom the procedure was applied in the common femoral artery (CFA) and with the venous intervention (p < 0.010 and p < 0.016; p = 0.004 and p = 0.001, respectively). We found that platelet count correlated negatively with the sac's maximum diameter and the volume (r = ­0.383, p < 0.001 and r = ­0.486, p < 0.001, respectively) duration of intervention correlated positively with the sac's maximum diameter and the volume (r = 0.205, p = 0.019 and r = 0.320, p < 0.001). Conclusion: Our study reveals that prolonged procedure duration, simultaneous arterial and venous accesses, peripheral artery disease, thrombocytopenia, and puncture site are the aggressive risk factors of pseudoaneurysms size after angiographic procedures.

Evaluation of major complications associated with percutaneous CT-guided biopsy of lung nodules below 3 cm

Background/aim: The aim of this study was to evaluate retrospectively the incidence and risk factors for the serious complications of pneumothorax and/or parenchymal haemorrhage occurring after computed tomography (CT) guided transthoracic biopsy. Materials and methods: The relation between the incidence of pneumothorax and parenchymal haemorrhage due to biopsy, age, sex, lesion localization, lesion size, duration of the procedure, depth of lesion, number of pleural insertions of the biopsy needle and pathology results were statistically evaluated. Results: Between 2016 and 2017, 309 cases with lesions below 3 cm in diameter of a total of 768 (40.2%) CT-guided chest biopsy patients were selected for retrospective review. The rate of pneumothorax and parenchymal haemorrhage was 18.1% (59/309) and 51% (158/309), respectively post biopsy. The number of needle pleural insertions was correlated with the development of pneumothorax (P = 0.002). At regression analysis, for parenchymal haemorrhage, lesion depth (P < 0.001) and total procedure time (p=0.036) were determined as the most important independent risk factors. Conclusion: Pneumothorax and parenchymal haemorrhage are common complications after CT-guided percutaneous biopsy. The minimum number of needle-pleural insertions, the optimal access route to the lesion and as quick as possible biopsy procedure should be selected to reduce the risk of pneumothorax and parenchymal haemorrhage.

Evaluation of the celiac trunk and its branching pattern by magnetic resonance angiography.

OBJECTIVE: The study aimed to examine the celiac trunk (CT) in detail by magnetic resonance angiography, to determine the locations, positions and variations of the CT, to provide detailed information for surgeons and interventional radiologists, and to reduce the time spent in the catheter angiography. MATERIAL AND METHODS: MR angiography images of 185 patients with abdominal imaging in PACS (Picture Archiving Communication Systems) were retrospectively analyzed. The level of origin of CT, according to the vertebral column, angle of origin, distance between CT and branches of the abdominal aorta (AA), and the branching pattern of CT were evaluated. Parameters were evaluated according to gender and age. RESULTS: The most common origin site for CT, according to the vertebral column, was found to be at T12-L1 in both genders. There was a low, positive correlation between age and CT-Sagittal angle (SA) in the whole study group (p<0.05). The most common CT branching pattern was the hepatogastrosplenic trunk in both genders, according to Adachi and Uflkacker's classification. The distance between CT and the inferior mesenteric artery (IMA) and CT and the aortic bifurcation (AB) of males was greater than in females, and the differences were statistically significant (p<0.05). CONCLUSION: Knowledge of the locations, positions, and variations of CT is essential in the diagnosis, differential diagnosis and decision-making mechanisms regarding the type of intervention to be performed for this vessel and related structures. In addition, the fact that data on these vessels can be obtained by MR angiography due to the improved image quality will prevent patients and physicians from the problems caused by the ionizing radiation of computed tomography. The data presented will constitute a basis for detailed and individualized interpretation and evaluation of each patient, as they provide important details about the configuration of the CT concerning gender and age using MRA.

Evaluation of the non-alcoholic fatty liver fibrosis score in predicting short-term outcomes and severe coronary artery disease in patients undergoing coronary computed tomography angiography.

Introduction: The correlation between non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease is well established. Aim: The objective of this study was to assess the short-term associations of the non-alcoholic fatty liver disease fibrosis score (NFS) with various outcomes, including mortality, severe coronary artery disease, myocardial infarction, and the need for coronary angiography, among patients who underwent coronary computed tomographic angiography (CCTA). Material and methods: In this study, we assessed 499 patients who underwent 640-slice CCTA and evaluated their liver fibrosis using the NFS. The NFS takes into account factors such as age, body mass index, impaired fasting glycemia or diabetes mellitus, aspartate aminotransferase/alanine aminotransferase ratio, platelets, and albumin. Our primary focus was myocardial infarction, the need for coronary angiography, and death. Additionally, we examined the association between NFS and severe coronary artery disease. Results: Patients with a higher NFS had a greater number of coronary angiography procedures and higher Agatston score (p < 0.001), with NFS and Agatston score emerging as independent predictors of severe coronary artery disease and the primary endpoint. An NFS value above -0.92 could predict the primary endpoint with 61% sensitivity and 63% specificity, while an NFS value above -0.88 could predict severe coronary artery disease with 62% sensitivity and 65% specificity. To analyze primary endpoints, the Kaplan-Meier method was used for survival analysis, with NFS groups compared using the log-rank test. During the follow-up period, patients with higher NFS were exposed to primary outcomes at an earlier period (p = 0.009). Conclusions: NFS is an effective predictor of major cardiovascular events such as death, myocardial infarction, severe coronary artery disease, and the need for coronary angiography. These findings underscore the importance of NFS as a valuable tool for risk assessment and early intervention in patients with suspected or confirmed coronary artery disease.

A Case of Subdural Hematoma without Subarachnoid Hemorrhage Secondary to Rupture of Posterior Communicating Artery-infundibular Dilatation.

INTRODUCTION: Subdural hematoma without subarachnoid hemorrhage secondary to intracranial aneurysm rupture is rare and may complicate patient management due to delay in diagnosis and subsequent treatment. Herein, we describe a case presenting with pure SDH secondary to the rupture of a posterior communicating artery infundibular dilatation (PcoA-ID). To the best of our knowledge, this is the first case of rupture of a PcoA-ID with SDH in the convexity and tentorium, which also tracked into the upper cervical spine along the subdural space. Additionally, we briefly discuss the previously published cases of pure SDH secondary to intracranial aneurysm rupture. CASE REPORT: A 44-year-old female presented with headache, dizziness, nausea and left-sided diplopia to an outside institution. Initial diagnostic work-up showed no intracranial hemorrhage, however, magnetic resonance angiography and subsequent digital subtraction angiography revealed left posterior communicating artery infundibular dilatation. Two days later, the patient presented with a loss of consciousness. Computed tomography was positive for bilateral hemispheric subdural hematoma with no evidence of subarachnoid hemorrhage. Digital subtraction angiography showed left posterior communicating artery infundibular dilatation and pseudoaneurysm originating from the inferior area of the infundibular dilatation, concerning recent rupture. Balloon assisted coil embolization was performed and the patient had a good outcome without any neurological deficit. CONCLUSION: Subdural hematoma in a young adult without a history of trauma or coagulopathy warrants additional vascular imaging to search for underlying vascular lesions. It should also be kept in mind that infundibular dilatation may rupture and cause a pure subdural hematoma.

Selective Arterial Embolisation of Uterine Arteriovenous Malformation in an Infertile Patient, subsequent Term Pregnancy and Postpartum Recurrence.

Uterine arteriovenous malformation (AVM) is a rare entity. This report describes selective catheterisation and embolisation of a uterine AVM in an infertile woman, subsequent spontaneous pregnancy and postpartum recurrence of the AVM treated with a second embolisation procedure. A 22-year woman presented with menometrorrhagia and failure to conceive. Pelvic magnetic resonance imaging showed a large uterine AVM. Selective catheterisation and embolisation of the AVM was performed. The patient conceived spontaneously two months later and delivered vaginally. A second embolisation was performed due to recurrence of uterine AVM at six months postpartum. This is the first case reporting postpartum recurrence of a pre-conceptionally treated uterine AVM. Selective catheterisation and embolisation is a minimally-invasive, fertility-preserving procedure that successfully treats uterine AVM and should be the treatment of choice when the patient desires pregnancy. Successful pregnancy and vaginal delivery following embolisation is possible; however, an increased awareness of postpartum AVM recurrence is required. Key Words: Fertility, Pregnancy, Therapeutic embolisation, Uterus, Arteriovenous malformation.

Association of quantitative computed tomography indices with lung function and extent of pulmonary fibrosis in patients with systemic sclerosis.

OBJECTIVES: The aim was to investigate the discriminative value of a wide range of quantitative computed tomography (qCT) parameters in systemic sclerosis (SSc) patients with and without pulmonary fibrosis (PF) and their association with pulmonary function tests (PFTs) and visual fibrosis scores (VFS). METHOD: Thoracic high-resolution computed tomography (HRCT) images of SSc patients with and without PF were analyzed with Vitrea® Advanced Visualization software. The mean lung attenuation (MLA), skewness, kurtosis, and threshold-based volumes [low-density volume (LDV), medium-density volume (MDV), and high-density volume (HDV)] derived from the attenuation histograms of the right and left lungs were evaluated separately. Visual scores were measured semi-quantitatively and the overall extent of pulmonary parenchymal abnormality was calculated. RESULTS: Forty-one SSc patients with PF (85.4% female; mean age 50.4 ± 15.6 years) were compared with 94 without PF (88.3% female; mean age 50 ± 11.5 years). All qCT parameters were significantly different between those with and without PF (p < 0.05). Amongst the qCT measurements, R-MLA, L-MLA, R-MDV, L-MDV, and left total lung volume (L-TLV) correlated with all three of forced vital capacity, carbon monoxide diffusion capacity, and VFS, even after adjustment for sex and age (|r|> 0.300 and p < 0.05). R-MLA, L-MLA, R-HDV/TLV, and L-HDV/TLV exhibited diagnostic accuracy in discriminating patients with PF (AUC value > 0.7). CONCLUSION: QCT parameters differentiated SSc patients with PF from the ones without and showed a good correlation with VFS. With the application of user-friendly and less operator-dependent software, qCT analysis may become an objective tool for analysis of PF in SSc, complementary to PFTs and VFS. Key Points • Quantitative computed tomography parameters can accurately and objectively differentiate between SSc patients with and without PF. • Furthermore, in SSc patients with fibrosis, a moderate to a high correlation was identified between many of the qCT parameters, PFT results, and VFS.

Malignant versus benign mediastinal lesions: quantitative assessment with diffusion weighted MR imaging.

OBJECTIVES: We aimed to evaluate the performance of diffusion-weighted magnetic resonance imaging in differentiating malignant from benign mediastinal lesions. METHODS: Fifty-three mediastinal lesions were examined with T1- and T2-weighted (W) conventional images. Then, two diffusion-weighted images were obtained with b = 0 and 1000 s/mm² values and apparent diffusion coefficients (ADC) were calculated. The statistical significance of differences between measurements was tested using the Student-t test. RESULTS: The mean ADC of malignant lesions was significantly lower than that of the benign masses (p < 0.001). The cut-off value of ≤ 1.39 × 10(-3) mm²/s indicated a malignant lesion with a sensitivity of 95% and specificity of 87%. CONCLUSION: Diffusion-weighted imaging may be helpful in differentiating benign from malignant mediastinal masses.

Aortoesophageal fistula secondary to thoracic endovascular aortic repair of a descending aortic aneurysm rupture.

PURPOSE: We present the case of a patient who developed an aortoesophageal fistula (AEF) 4 years after thoracic endovascular aortic repair (TEVAR) of a descending thoracic aortic aneurysm rupture. CASE REPORT: A 60-year-old female patient underwent emergency stent graft placement in December 2006 because of rupture of a distal descending aortic aneurysm. The patient was discharged uneventfully. Four years later, the patient was readmitted because of recurrent hematemesis, weight loss, and malaise. A computed tomography scan and an upper gastrointestinal system (GIS) endoscopy examination revealed an AEF located at the midportion of the esophagus and at the caudal end of the stent graft. An emergency stent graft was re-replaced into the previous graft. The patient died from hemorrhagic shock due to massive GIS bleeding while she was being prepared for secondary major esophageal surgery. CONCLUSION: AEF is a catastrophic complication of TEVAR. Conservative treatment is often associated with fatal results. If possible, these patients should be treated with secondary major surgical procedures.

Intravoxel incoherent motion magnetic resonance imaging for breast cancer: A comparison with molecular subtypes and histological grades.

PURPOSE: The purpose of this paper is to investigate whether the IVIM parameters (D, D *, f) helps to determine the molecular subtypes and histological grades of breast cancer. METHODS: Fifty-one patients with breast cancer were included in the study. All subjects were examined by 3 T Magnetic Resonance Imaging (MRI). Diffusion-weighted imaging (DWI) was undertaken with 16 b-values. IVIM parameters [D (true diffusion coefficient), D* (pseudo-diffusion coefficient), f (perfusion fraction)] were calculated. Histopathological reports were reviewed to histological grade, histological type, and immunohistochemistry. IVIM parameters of tumors with different histological grades and molecular subtypes were compared. RESULTS: D* and f were significantly different between molecular subtypes (p = 0.019, p = 0.03 respectively). D* and f were higher in the HER-2 group and lower in Triple negative (-) group (D*:36.8 × 10-3 ± 5.3 × 10-3 mm2/s, f:29.5%, D*:29.8 × 10-3 ± 5.6 × 10-3 mm2/s, f:21.5% respectively). There was a significant difference in D* and f between HER-2 and Triple (-) subgroups (p = 0,028, p = 0.024, respectively). D* was also significantly different between the HER-2 group and the Luminal group (p = 0,041). While histological grades increase, D and f values tend to decrease, and D* tends to increase. While the Ki-67 index increases, D* and f values tend to increase, and D tend to decrease. CONCLUSION: D* and f values measured with IVIM imaging were useful for assessing breast cancer molecular subtyping. IVIM imaging may be an alternative to breast biopsy for sub-typing of breast cancer with further research.

Renal artery aneurysm in a hypertensive child treated by percutaneous coil embolization.

A 16-year-old boy was admitted to our hospital with uncontrolled hypertension. A left renal artery aneurysm was detected on colour Doppler US and CT. Renal arteriography demonstrated the aneurysm and focal renal parenchymal areas of decreased perfusion. The renal artery aneurysm was successfully treated by transcatheter coil embolization.

PHACE Syndrome: A Rare Case.

PHACE syndrome (OMIM 606519) is a rare neurocutaneous vascular disorder, characterized by posterior fossa malformations, large cervicofacial infantile hemangiomas, arterial anomalies, aortic coarctation, cardiac abnormalities, and eye abnormalities. The long-term outcome of PHACE syndrome patients is unclear; however, it seems that they are at risk for childhood stroke. The radiologist has an important role on diagnosis of PHACE syndrome and in the assessment of potential complications. Investigation of infants with segmental craniofacial hemangiomas should include cranial magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the cerebral and cervical arteries. Brain MRI and MRA findings of a 5-year-old female patient with PHACE syndrome are presented.

Color Doppler ultrasonographic flow parameters in the differentiation of benign and malignant causes of omental thickening.

OBJECTIVE: The purpose of the study was to determine if color Doppler ultrasonographic (US) quantitative flow parameters are valuable to differentiate malignant peritoneal or omental involvement from benign causes. MATERIALS AND METHODS: Twenty-six consecutive patients with peritoneal or omental thickening detected by gray scale US, computed tomography, and magnetic resonance underwent color Doppler US examinations. All the Doppler signal waveforms were recorded, and resistive (RI) and pulsatility indices (PI) were calculated automatically by the US machine. In the statistical analysis of RI and PI, unpaired t test was used. A P < 0.05 was considered significant. RESULTS: Nineteen of 20 malignant and 5 of 6 benign lesions had detectable color Doppler US pulsatile flow signals. The mean RI and PI values were 0.6260 and 1.36, respectively, for the benign group and 0.5384 and 1.4147, respectively, for the malignant group. For malignant lesions, mean RI was lower (P = 0.0796), and mean PI was higher (P = 0.9183) than benign lesions. However, these differences were not statistically significant. CONCLUSIONS: Overlapping RI and PI values in benign and malignant omental lesions limit the clinical value of flow parameters in the differentiation of benign and malignant involvement of the omentum.

Acute lymphoblastic leukaemia presenting with acute renal failure: report of two cases.

Acute renal failure is a well-recognized complication of acute leukaemias. Howevcr, serious renal failure caused by leukaemic infiltration as a primary manifestation is unusual. Here we report two patients with acute lymphoblastic leukaemia presenting with acute renal failure due to leukaemic infiltration. The first patient died before the administration of specific therapy for leukaemia, whereas the second case recovered after chemotherapy. She was discharged without necessitating dialysis therapy.

Silent cerebral infarction in chronic heart failure: ischemic and nonischemic dilated cardiomyopathy.

OBJECTIVES: Patients with dilated cardiomyopathy (DCM) may have a high incidence of clinically asymptomatic silent cerebral infarction (SCI). Prevalence of SCI and its risk factors may differ between ischemic and nonischemic DCM. The purpose of this study was to evaluate prevalence and related parameters of silent cerebral infarction in patients with ischemic and nonischemic DCM. METHODS: Patients with ischemic and nonischemic DCM (53 male, 19 female, aged 62 +/- 12 years) were included in the study. Etiology of DCM was ischemic in 46 and nonischemic in 26 patients. Fifty-six age- and gender-matched healthy volunteers served as a control group for comparison of SCI prevalence. RESULTS: Prevalence of SCI was 39%, 27%, and 3.6% in ischemic, nonischemic DCM, and control group, respectively (ischemic DCM vs control group, p < 0.001, nonischemic DCM vs control group, p = 002). In patients with nonischemic DCM, the mean age of the subjects with SCI was significantly higher than that of subjects without lesions (67 +/- 5 years vs 53 +/- 13, p < 0.001), whereas in ischemic DCM NHYA Functional Class was statistically higher in patients with SCI than without SCI (p = 0.03). In both groups, patients with SCI had lower systolic functions than patients with normal MRI findings. In multivariable logistic regression analysis, restrictive type of diastolic filling pattern was found as an independent factor for SCI occurrence on the whole patient population (OR: 16.5, 95% CI: 4.4-61.8, p < 0.001). CONCLUSION: SCI is common in patients with both ischemic and nonischemic DCM. In univariate analysis, both groups have similar systolic and diastolic characteristics in the occurrence of SCI. Logistic regression analysis revealed that restrictive diastolic filling pattern is an independent risk factor in the occurrence of SCI for the whole patient population.

Diffusion-weighted imaging in the differential diagnosis of simple and hydatid cysts of the liver.

OBJECTIVE: The purpose of our study was to evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of simple and hydatid cysts of the liver, particularly in the completely liquid type of hydatid cyst. SUBJECTS AND METHODS: Eighty-two cysts (43 simple cysts, 39 hydatid cysts) were included in this prospective study. DWI was performed using a breath-hold single-shot echo-planar spin-echo sequence, and apparent diffusion coefficients (ADCs) were calculated. On DW trace images, the signal intensity of cysts was visually compared with the signal intensity of the liver using a 3-point scale: 0, isointense; 1, moderately hyperintense; and 2, significantly hyperintense. Quantitatively, signal intensity of the cysts, cyst-to-liver signal intensity ratios, ADC of the cysts, and cyst-to-liver ADC ratios were compared between the groups. The statistical significance was determined using the Mann-Whitney U test. RESULTS: On trace DWI (b = 1,000 s/mm2), most hydatid cysts (37/39, 95%) were hyperintense, whereas most simple cysts (40/43, 93%) were isointense with the liver. Three simple cysts (7%) were moderately hyperintense and two hydatid cysts (5%) were isointense. Quantitatively, both the signal intensity and cyst-to-liver signal intensity ratio of the hydatid cysts were significantly higher than those for simple cysts (p < 0.001). The cutoff value at 1.5 yielded a sensitivity of 77%, a specificity of 86%, and positive predictive value of 83% for the cyst-to-liver signal intensity ratio. The ADC and cyst-to-liver ADC ratio of the hydatid cysts were significantly lower than those of simple cysts (p < 0.005). For the completely liquid type in particular, we observed statistically significant differences in signal intensity, signal intensity ratio, ADC, and ADC ratios from those of simple cysts (p < 0.005). With a cutoff value of 1.5, signal intensity ratio had a sensitivity of 81%, specificity of 86%, and positive predictive value of 74%. CONCLUSION: DWI may help in the differential diagnosis of hydatid and simple cysts of the liver.

Spontaneous vaginal expulsion of an infected necrotic cervical fibroid through a cervical fistula after uterine artery embolization: a case report.

BACKGROUND: Uterine artery embolization (UAE) is promising, minimally invasive therapy being offered to women for treatment of fibroids. Although it seems to be safe and effective, major complications and adverse outcomes have been reported. CASE: A patient treated with UAE for a huge cervical fibroid presented with an infected, necrotic cervical mass lesion 4 weeks after the procedure. Spontaneous vaginal expulsion of the infected cervical fibroid from the left lateral cervical fistula tract occurred 3 weeks later while the patient was receiving antibiotic therapy. After 6 months of intervention, an approximately 99% regression rate in the fibroid volume was achieved. The patient gave birth to a healthy, female infant following a spontaneous, uneventful pregnancy and vaginal delivery. CONCLUSION: UAE appears to be associated with a significant reduction in fibroid volume. Expulsion of the infected, necrotic parts of the fibroid after UAE may be accepted as a natural process. Warning the patient about this potential risk, early recognition of infective complications and lose follow up seem to be crucial to avoiding potentially fatal septic shock.

Spontaneous pseudoaneurysm of the superficial femoral artery in Behcet's disease-endovascular stent-graft treatment combined with percutaneous drainage: a case report.

Behcet's disease is a rare multisystemic chronic autoimmune disorder characterized by a classic triad of urogenital ulcerations, chronic eye inflammation, and skin lesions. We report on a case of a spontaneous pseudoaneurysm of the superficial femoral artery caused by Behcet's disease that was treated with an endovascular stent-graft followed by percutaneous drainage. We emphasize the use of percutaneous drainage of the pseudoaneurysm to decrease compression on the stent-graft and native vessel.

Silent cerebral infarction in patients with dilated cardiomyopathy: echocardiographic correlates.

BACKGROUND: Patients with dilated cardiomyopathy (DCM) have an increased risk of thromboembolic events. Incidence of silent cerebral infarction (SCI) has not been investigated in these patients. The aim of this study was to investigate the incidence of SCI in patients with DCM and to determine its associations with echocardiographic parameters. METHODS AND RESULTS: Seventy-two patients (mean age 62+/-12 years) with DCM underwent cranial magnetic resonance imaging in addition to transthoracic and transesophageal echocardiographic examination. A total of 56 age-matched healthy volunteers served as a control group for comparison SCI prevalence. Prevalence of SCI was significantly higher in patients with DCM (35% vs. 3.6%; p<0.001). In DCM group, patients with SCI had significantly impaired left ventricular systolic function, higher frequency of restrictive diastolic filling, moderate to severe left atrial spontaneous echo contrast (SEC), aortic SEC, and complex atherosclerosis or calcified plaques in the aorta. In logistic regression analysis, type of diastolic filling emerged as the only independent risk factor for SCI (p<0.001). When the type of diastolic filling was removed from the analysis, ejection fraction, marked left atrial SEC, complex-calcified aortic atheroma and age appeared as the other independent risk factors (p = 0.003, p = 0.009, p = 0.013 and p = 0.018, respectively). CONCLUSION: SCI is a frequent finding in DCM patients. Impaired systolic function, restrictive filling pattern, presence of moderate to severe left atrial SEC, and complex atherosclerosis in the aorta are the factors contributing to the development of SCI.

MRI patterns in orbital malignant lymphoma and atypical lymphocytic infiltrates.

OBJECTIVE: To evaluate the potential of MRI in differentiating between malignant lymphomas and atypical lymphocytic infiltrates in the orbit. MATERIALS AND METHODS: MRI, clinical and histopathological findings in 30 patients presenting with orbital lymphoproliferative diseases (malignant lymphoma and atypical lymphocytic infiltrates) were evaluated. RESULTS: MRI detected 28 out of 30 (93%) orbital lymphoid tumors. Seven out of eight (87.5%) atypical lymphocytic infiltrates and 21/22 (95.4%) of malignant lymphomas were detected. One conjunctival malignant lymphoma and one conjunctival atypical lymphocytic infiltrate were missed. Only malignant lymphoma lesions were hyperintense compared to the extraocular muscles on precontrast and postcontrast T1-weighted images. The lacrimal duct was involved only with malignant lymphoma. Bilateral disease was more likely to be malignant lymphoma. Intraconal lesions were more likely to be associated with lesions elsewhere. No malignant lymphoma involved the extraconal fat. Only intraconal atypical lymphocytic infiltrates had indistinct margins. CONCLUSION: In the orbit, MRI features alone may not allow clear-cut differentiation of malignant lymphomas from atypical lymphocytic infiltrates. However, certain imaging features increase the likelihood of distinguishing them. MRI may miss conjunctival disease. Both orbits should be imaged when orbital lymphoid disease is a probability. The presence of intraconal disease should prompt a search for lesions elsewhere. The use of a head coil instead of a superficial coil may be advantageous by eliminating coil shine effect and allowing evaluation of both orbits. Comparison of lesion signal to extraocular muscle signal appears to be a better alternative than cerebral gray matter or periorbital fat in differentiating malignant lymphoma from atypical lymphocytic infiltrates. Since imaging findings overlap, histopathological diagnosis is necessary in all cases.