Variations of the aortic arch - a study on the most common branching patterns.

BACKGROUND: Anatomical variants of the aortic arch and its branching patterns often appear as an incidental finding during routine computed tomography (CT) scanning. These variations can be of relevance when performing angiography or endovascular interventions and may cause symptoms such as dysphagia. PURPOSE: To analyze common anatomical variations found within the arteries originating from the aortic arch in patients using contrast CT imaging techniques. MATERIAL AND METHODS: A total of 2033 contrast CT scans were analyzed. To obtain a truly representative sample, cases were chosen from different hospital departments without previous knowledge of the patient history. RESULTS: The total percentage of variations within the analyzed patients was 13.3%. In 8.0% a truncus bicaroticus was found. 4.2% of the patients showed a left vertebral artery originating directly from the aortic arch, mostly proximal, and in 1 case distal to the left subclavian artery. In 1.0% we found an aberrant right subclavian artery. We also found a single case of a right descending aortic arch. CONCLUSION: Variations of the aortic arch and its branching are frequently found, mostly as an incidental finding during routine diagnostic scanning. A contrast-enhanced CT scan is a good method with which to study the aortic arch and its associated branching pattern.

Clinical value of 18F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography (18F-DOPA PET/CT) for detecting pheochromocytoma.

PURPOSE: In detecting pheochromocytoma (PHEO), positron emission tomography (PET) with the radiolabelled amine precursor (18)F-fluorodihydroxyphenylalanine ((18)F-DOPA) offers excellent specificity, while computed tomography (CT) provides high sensitivity and ability to localize lesions; therefore, the combination of these modalities could be advantageous in this setting. The aim of this study was to investigate whether combined (18)F-DOPA PET/CT more accurately detects and localizes PHEO lesions than does each modality alone. METHODS: (18)F-DOPA PET, CT and (18)F-DOPA PET/CT images of 25 consecutive patients undergoing diagnostic scanning of suspected sporadic or multiple endocrine neoplasia type 2 syndrome-associated PHEO were reviewed retrospectively in randomized sequence. Two blinded observers scored the images regarding the likelihood of PHEO being present and localizable. Results were correlated with subsequent clinical history and, when available, histology. RESULTS: Of the 19 lesions detected by all three modalities, PET identified each as positive for PHEO, but was unable to definitively localize 15 of 19 (79%). CT could definitively localize all 19 lesions, but could not definitively diagnose or exclude PHEO in 18 of 19 (95%) lesions. Furthermore, CT falsely identified as negative for PHEO one lesion which was judged to be positive for this tumor by both PET and PET/CT. Only in PET/CT scans were all 19 lesions accurately characterized and localized. On a per-patient basis, the sensitivity of (18)F-DOPA PET/CT for PHEO was 100% and the specificity 88%, with a 100% positive predictive value and an 88% negative predictive value. CONCLUSION: (18)F-DOPA PET/CT more accurately diagnoses and localizes adrenal and extra-adrenal masses suspicious for PHEO than do (18)F-DOPA PET or CT alone.

Integrated FDG-PET-CT: its role in the assessment of bone and soft tissue tumors.

PURPOSE: The purpose of this study was to evaluate prospectively, whether integrated 2-deoxy-2-[(18)F]fluoro-D: -glucose positron emission tomography-computed tomography (FDG-PET-CT) is more accurate for determination musculoskeletal tumors compared with separate interpretation of CT and FDG-PET, because most of the current clinical data come from patients studied with PET. METHODS: Eighty patients with newly diagnosed musculoskeletal tumors underwent FDG-PET-CT. CT, FDG-PET, and FDG-PET-CT were interpreted separately to determine the performance of each imaging modality. RESULTS: Assuming that equivocal lesions are benign, performance of diagnostic tests was as follows: sensitivity, specificity and accuracy for CT alone was 81, 84, 83%, for PET 71, 82, 76, and for PET-CT 80, 83 and 86%. Assuming that equivocal lesions are malignant, sensitivity, specificity, and accuracy for CT was 61, 100, 70%, for PET 69, 100, 79, and for PET-CT 69, 100 and 79%. CONCLUSIONS: Combined FDG-PET-CT reliably differentiates soft tissue and bone tumors from benign lesions. The value of the information provided by FDG-PET-CT for planning surgical procedures must be evaluated in further studies.

Detection of bone metastases in patients with lung cancer: 99mTc-MDP planar bone scintigraphy, 18F-fluoride PET or 18F-FDG PET/CT.

PURPOSE: The aim of the study was to compare the diagnostic accuracy of (18)F-fluorodeoxyglucose (FDG) PET/CT versus standard planar bone scintigraphy (BS) and (18)F-labelled NaF ((18)F) PET for the detection of bone metastases (BM) in non-small cell lung cancer (NSCLC). METHODS: (18)F-FDG PET/CT was performed in 126 patients with NSCLC. Within 7 days BS (n = 58) or (18)F PET (n = 68) was performed. (18)F-FDG PET/CT, BS and (18)F PET were evaluated by two experienced readers. Lesions were graded on a scale from 1 (definite BM) to 5 (degenerative lesion), and equivocal lesions were determined as indifferent (grade 3). RESULTS: A total of 92 patients showed degenerative lesions (grade 4/5) on PET/CT, BS or (18)F PET. In 34 patients (27%) BM lesions were diagnosed (grades 1 and 2). In 13 of 18 patients BM were concordantly diagnosed with PET/CT and (18)F PET. PET/CT showed more BM compared to (18)F PET (53 vs 40). In one patient one osteolytic BM was false-negative on (18)F PET. However, (18)F PET identified four patients with BM compared to negative findings on PET/CT. Of 16 patients, 11 had concordant findings of BM on PET/CT and BS. In three patients BS was false-negative and in two patients BM were diagnosed as indifferent. CONCLUSION: Integrated (18)F-FDG PET/CT is superior to BS in the detection of osteolytic BM in NSCLC. Thus, PET/CT may obviate the need to perform additional BS or (18)F PET in the staging of NSCLC, which significantly reduces costs.

Challenging complications of treatment--human herpes virus 6 encephalitis and pneumonitis in a patient undergoing autologous stem cell transplantation for relapsed Hodgkin's disease: a case report.

BACKGROUND: Reactivation of human herpesvirus 6 (HHV-6) occurs frequently in patients after allogeneic stem cell transplantation and is associated with bone-marrow suppression, enteritis, pneumonitis, pericarditis and also encephalitis. After autologous stem cell transplantation or intensive polychemotherapy HHV-6 reactivation is rarely reported. CASE REPORT: This case demonstrates a severe symptomatic HHV-6 infection with encephalitis and pneumonitis after autologous stem cell transplantation of a patient with relapsed Hodgkin's disease. CONCLUSION: Careful diagnostic work up in patients with severe complications after autologous stem cell transplantation is mandatory to identify uncommon infections.

Lymphangioleiomyomatosis: solitary abdominal manifestation (2009: 9b).

Lymphangioleiomyomatosis (LAM) is a rare disease that usually affects premenopausal woman and is characterized by cystic lung lesions and lymphatic disorders. We report a case of a 23-year-old woman who presented with diffuse, but increasing abdominal pain. Transabdominal ultrasound showed multiple cystic formations. Due to the patient's uncharacteristic symptoms, an exploratory laparotomy with tissue sampling was performed, and the diagnosis of LAM was confirmed by two independent pathologists. With computed tomography a broad abdominal, but no pulmonary, manifestation could be established. During sirolimus therapy the patient showed clinical benefit, but only slight progress in computed tomography.

The cisterna chyli: prevalence, characteristics and predisposing factors.

The purpose of this study was to determine the prevalence and characteristics of the cisterna chyli (CC) in a large 3,000-patient cohort and to identify potential predisposing factors for the development of a CC. Three thousand consecutive contrast-enhanced CT examinations (1,261 women, 1,739 men, mean age 61.0 years) of the chest and/or abdomen were included in this retrospective study. Imaging characteristics of the CC (size, attenuation, location) were documented as well as clinical information (malignant disease, pattern of metastasis). A CC was found in 16.1% of the patients with an average volume of 302 microl. The mean attenuation was 4.8 Hounsfield units (HU). Twenty percent of the CC showed CT densities of 15 HU and higher. Patients with malignancies showed a significantly (p < 0.001) higher prevalence of CC (340/1,757, 19.4%) than patients with benign conditions (144/1,243, 11.6%). Especially the finding of a large CC (>1,000 microl) represents an elevated relative risk for malignancy of 1.7 (p = 0.0017). We found a significant association between malignant disease and the presence and size of a cisterna chyli. Identifying the continuity between the CC and the thoracic duct is a safer method to distinguish a CC from retrocrural lymph nodes than near-water CT attenuation alone.

Pitfalls in abdominal diffusion-weighted imaging: how predictive is restricted water diffusion for malignancy.

OBJECTIVE: As diffusion-weighted imaging is increasingly implemented into routine protocols of abdominal MRI, abnormal findings in expected and unexpected locations become more common. The aim of our retrospective study was to investigate the specificity of restricted diffusion in differentiation of benign from malignant abdominal disease. MATERIALS AND METHODS: Two hundred thirty consecutively registered patients underwent abdominal MRI including diffusion-weighted imaging (single-shot spin-echo echo-planar sequence) with b values of 0, 150, 500, and 1,000 s/mm(2). Lesions were detected by two blinded readers using only the images with a b value of 1,000 s/mm(2), and representative apparent diffusion coefficients were measured. Lymph nodes were not documented. RESULTS: Fifty-two of the 230 patients had a total of 55 lesions with restricted diffusion (23.9%). The mean apparent diffusion coefficient was 809 mm(2)/s. Forty-three lesions (78.2%) were malignant. The 12 benign lesions were liver hemangioma, liver adenoma, autoimmune pancreatitis, pancreatic teratoma, two abscesses, three cases of inflammatory bowel wall thickening due to Crohn's disease, Bartholin cyst, hemorrhagic ovarian cyst, and renal Rosai-Dorfman disease. CONCLUSION: Restricted diffusion is generally considered to be associated with malignant tumors because of the high cellularity of these tumors. However, in interpretation of diffusion-weighted images, it should be kept in mind that a number of benign lesions, as many as 22% in our cohort, can exhibit restricted diffusion on images with high b values, thus mimicking malignant lesions.

Performance of integrated FDG-PET/CT for differentiating benign and malignant lung lesions--results from a large prospective clinical trial.

PURPOSE: The purpose of the study was to evaluate prospectively whether integrated 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) is more accurate for determination of malignancy in newly diagnosed pulmonary lesions compared to separate interpretation of CT and FDG-PET. PROCEDURES: Two hundred and seventy-six patients with newly diagnosed lung lesions underwent FDG-PET/CT. Helical CT, FDG-PET, and FDG-PET/CT were interpreted separately to determine the performance of each imaging modality. Histopathology served as reference in all patients, and in further 60 patients, a benign lesion was verified at follow-up (mean follow-up of 1,040 days). RESULTS: Histology revealed malignant lung tumors in 216 of 276 patients. With PET and PET/CT, a significantly lower number of lesions were classified as equivocal compared to CT alone (p < 0.001). Assuming that equivocal lesions are benign, performance of diagnostic tests was as follows: sensitivity, specificity, and accuracy for CT was 94, 75, and 90%, for PET 97, 83, and 94% (p = 0.021), and for PET/CT 96, 87, and 94% (p = 0.010). Assuming that equivocal lesions are malignant, sensitivity, specificity, and accuracy for CT was 99, 37, and 86%, for PET 99, 77, and 94% (p < 0.001), and for PET/CT 98, 68, and 92% (p = 0.002). PET and PET/CT showed the highest concordance (K = 0.912; confidence interval 0.866-0.958). In lesions less than or equal to 3 cm, there was a significant difference in the performance of PET alone and multidetector row CT as well as PET/CT and multidetector row CT (p = 0.007), irrespective if equivocal findings were judged as malignant or benign. CONCLUSION: For differentiation of benign from malignant lung lesions, integrated FDG-PET/CT imaging was significantly more accurate than CT but not FDG-PET. The addition of metabolic imaging (FDG-PET) to morphological imaging (CT) leads to an increase in specificity and significantly reduced equivocal findings and is therefore recommended to further specify newly diagnosed lung lesions.

Evaluation of lung tumor perfusion by dynamic contrast-enhanced MRI.

The characterization of solid pulmonary lesions with imaging methods remains a diagnostic challenge. The aim of this study was to correlate kinetic parameters of dynamic perfusion magnetic resonance imaging (MRI) with histological tumor classification. Dynamic contrast-enhanced MRI of 31 patients with pulmonary masses (five benign lesions, 26 malignant tumors) was acquired in the tumor areas every 20 s for a mean duration of 124 s. Contrast uptake (CU) was measured by signal analysis in regions of interest (ROIs). The beginning and duration of CU, maximum CU (MCU, % of baseline), maximum contrast upslope (%/s) and the delay to the maximum contrast upslope (s) were calculated. All lesions were classified histologically. The beginning of CU correlated significantly with the MCU delay in all lesions (P=.033). The frequency of a plateau phase was higher in malignant tumors compared to benign lesions (P=.031). Masses with a high MCU showed more frequently a washout of contrast medium after a plateau phase (P=.006) and a higher maximum contrast upslope (P<.001). The MCU delay time was shorter in adenocarcinoma than in squamous cell carcinoma (P=.004). These results indicate that dynamic contrast enhanced MRI might become instrumental in differentiating benign from malignant intrapulmonary tumors and distinguishing adenocarcinoma from squamous cell carcinoma.

Comparison of manual and automated size measurements of lung metastases on MDCT images: potential influence on therapeutic decisions.

PURPOSE: The goal of this study was to evaluate the influence of automated measurement of diameter, area, and volume from chest CT scans on therapeutic decisions of lung nodules as compared to manual 2-D measurements. PATIENTS AND METHOD: The retrospective study involved 25 patients with 75 lung metastases. Contrast enhanced CT scans (16 row) of the lung were performed three times during chemotherapy with a mean time interval of 67.9 days between scans. In each patient, three metastases were evaluated (n=225). Automatic measurements were compared to manual assessment for the following parameters: diameter, area, and density. The influence on the therapeutic decisions was evaluated using the RECIST criteria. RESULTS: The maximum diameter measured by the automatic application was on an average 27% (S.D. 39; CI: 0.22-0.32; p<0.0001) higher than the maximum diameter with manual assessment, and the differences depended on metastases size. Based on diameter calculation, manual and automated assessment disagreed in up to 32% of therapeutic decisions. Volumetric assessment tended towards more changes in therapy as compared to diameter calculation. The calculation of mean transversal area of metastases was 36% (S.D. 0.305; CI: -0.40 to -0.32; p<0.0001) less with automated measurement. Therapeutic strategy would be changed in up to 25.7% of nodules using automated area calculation. Automated assessment of nodules' area and volume could influence the therapeutic decisions in up to 51.4% of all nodules. Density of the nodules was not validated to determine the influence on therapeutic decisions. CONCLUSION: There is a discrepancy between the manual and automated size measurement of lung metastases which could be significant.

A 25-year-old woman with a gastric GIST and a PET-positive epicardial tumor.

BACKGROUND: A 25-year-old woman presented with a history of abdominal pain. Endoscopy of the upper gastrointestinal tract revealed a tumor that protruded into the prepyloric antrum. After resection, a 'high-risk' gastrointestinal stromal tumor was histologically confirmed. INVESTIGATIONS: Endoscopy, endoscopic ultrasound, hemigastrectomy, [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT scan, histological examination, immunohistochemistry, cardiac MRI, high-resolution CT with electrocardiogram gating, CT angiography, and cardiac surgery. DIAGNOSIS: Gastrointestinal stromal tumor, epicardial paraganglioma, and Carney's syndrome. MANAGEMENT: Abdominal ultrasound and endoscopy combined with endoscopic ultrasound, annual FDG-PET/CT scan.

Evidence-based diagnosis and staging of pancreatic cancer.

Only 20% of patients who present with pancreatic cancer will be amenable to potentially curative resection. Therefore, it is necessary to reliably identify patients who might benefit from major surgical intervention by employing the appropriate staging methods. In this review, the pros and cons of each imaging technique are discussed and an algorithm for single and combined use of the different imaging modalities is proposed. To date, contrast-enhanced multi-detector row helical CT (MDR-CT) together with endoscopic ultrasound (EUS) remain the first staging methods of choice. MDR-CT has a high sensitivity for identifying vascular invasion and EUS is able to detect lesions as small as 2-3 mm. ERCP is performed mainly in patients with biliary obstruction with the option for therapeutic intervention during the same session. MRI with MR-angiography, MRCP, PET/CT and staging laparoscopy are additional modalities which might give further information in cases of equivocal findings by MDR-CT and EUS. The role of tumour markers such as CA 19-9 and CEA is reserved for monitoring and diagnosing post-surgery recurrence. Cytological or histological confirmation should usually be performed in patients that are not eligible for surgery prior to the commencement of palliative radio- or chemotherapy. In the routine clinical setting, MDR-CT and EUS play the predominant roles by providing the most cost-effective and accurate means for diagnosing and staging most cases of pancreatic cancer.

[Erdheim-chester disease: a rare cause of interstitial lung disease]. / Erdheim-Chester-Erkrankung: seltene Ursache einer interstitiellen Lungenerkrankung.

BACKGROUND: Erdheim-Chester disease is a rare non-Langerhans' cell histiocytosis of unknown etiology with typical osteosclerotic long-bone findings. However, clinical symptoms are mostly due to disease involvement of other tissues, particularly of the lung, heart and retroperitoneum. CASE REPORT: A 58-year-old man presented with fatigue, diffuse pain of the lower extremities, dyspnea, and a dry cough. Physical examination was unremarkable. Chest X-ray revealed an extensive bilateral pulmonary inter interstitial process. Computed tomography demonstrated pulmonary fibrosis, periaortic fibrosis of the thoracic aorta, and retroperitoneal fibrosis. The diagnosis of Erdheim-Chester disease was confirmed by minimally invasive lung biopsy. Steroid therapy was not tolerated. Following a stable interval of 18 months there was a disease progression, which could be stabilized after the initiation of cyclophosphamide therapy. CONCLUSION: In patients with extensive pulmonary fibrosis and coincidence of other organ manifestations such as periaortic or retroperitoneal fibrosis and particularly in case of symmetrical osteosclerotic bone lesions, Erdheim-Chester disease should be considered. Immunosuppressive therapy can lead to a stabilization or even improvement of the disease.

Multi-detector row CT: is prospective electrocardiographic triggering improving the detection of small pulmonary tumors?

RATIONALE AND OBJECTIVES: To compare prospectively ECG-triggered multi-detector row computed tomography (ECG-MDR-CT) and multi-detector row computed tomography (MDR-CT) without triggering for the detection of pulmonary tumors. MATERIALS AND METHODS: 100 patients with proven or suspected tumors were referred for CT of the lung for staging of lung metastases. First, a non-enhanced scan was performed using prospective ECG-triggering on a four-row multidetector helical CT scanner, followed by a contrast-enhanced scan without triggering. The diagnostic assessibility in detecting intrapulmonary nodules and mediastinal structures was graded using a 5-point scale (rated 1 = bad to 5 = very good image quality). RESULTS: ECG-MDR-CT images detected a total of 26% more pulmonary nodules than MDR-CT. For tumors <5 mm, the detection rate was 62% higher using ECG-triggered scans (P = .024). Subjective assessment found median demarcation ratings for all pulmonary findings of 4 (ECG-MDR-CT) versus 3 (MDR-CT). Mediastinal structures were delineated better using ECG triggering. The median ranking for demarcation of pulmonary findings <10 mm was 4 on ECG-MDR-CT and 3 on MDR-CT, respectively. For vessels and the left bronchus, the median of demarcation was 4 on triggered images and 2 on MDR-CT, respectively. The median values referring to the demarcation of mediastinal structures were not significantly different between ECG-MDR-CT and MDR-CT. CONCLUSION: Our data indicate the superiority of prospectively triggered ECG-MDR-CT over MDR-CT for the diagnosis of small pulmonary tumors using a 4-row multidetector CT.

[Impact of a guiding CT prior to angiographic intervention]. / Multidetektor-Reihen-CT (16x) zur Planung von angiographischen Interventionen.

With these two cases we want to demonstrate the additional impact of contrast enhanced multi-detector-row-CT angiography (MDR-CTA) compared to digital subtraction angiography (DSA) for planning of angiographic intervention. In selected cases a pre-interventional CTA can be useful to facilitate angiographic intervention. We selected two patients with different disease entities (bleeding caused by hepatic aneurysmosis; hepatocellular carcinoma (HCC) prior to transarterial chemoembolization (TACE) with aberrant arteries) from our collective who underwent CTA prior to angiographic intervention. The CT scans were performed using a 16 channel Multi-Detector-Row-CT (Philips Mx8000 IDT). Both multiplanar reconstructions (MPR) and slab maximum intensity projections (slab MIP) were performed. After CTA, patients underwent angiographic intervention (coil embolisation in the first case, TACE in the second case). MDR-CTA can not only find the cause of hemorrhage but also demonstrate the exact localization of the specific vascular pathology (first case). These findings facilitate the intervention, resulting in decreased table time in the angio suite and a reduction in radiation exposure. The second case illustrates the anatomic detail achievable with MDR-CTA. Even very small aberrant arteries (crucial to the success of TACE) are revealed. These arteries did not show in overview DSA and required superselective catheterization (only performed after MDR-CTA). These cases show that MDR-CTA can provide important informations in planning of interventional procedures.

[Value of spiral CT and MRI (1.5 T) in preoperative diagnosis of tumors of the head of the pancreas]. / Wertigkeit von Spiral-CT und MRT (1,5T) zur präoperativen Diagnostik von Pankreaskopftumoren.

OBJECTIVE: Prospective comparison study of helical computed tomography (HCT) and magnetic resonance imaging (MRI, 1.5-tesla field strength) with regard to their role in planning surgical therapy in a defined, homogeneous patient collective with tumors of the pancreatic head. PATIENTS AND METHODS: Sixty-one patients with clinical/ultrasound evidence of tumor were examined by HCT and MRI. Findings were compared with surgical anatomy and histology using a data documentation sheet. Factors evaluated included the malignancy of the tumors and the probability of correct diagnosis in relation to tumor size, as well as the occurrence of lymph node and distant metastases, arterial and portal-venous infiltration, extrapancreatic infiltration, determination of resectability and tumor staging (TNM classification). These factors were compared on the basis of their respective sensitivity, specificity, negative and positive predictive value and accuracy. RESULTS: Malignancy was correctly diagnosed by HCT and MRI in 82% and 77%, respectively, with a corresponding sensitivity for malignancy of 86% and 68%. Tumors with diameters > 2 cm were detected in 100% of cases by HCT and in 88% by MRI, while tumors with diameters < 2 cm were correctly diagnosed by HCT and MRI in 60% and 40% of cases. Respective rates of correct diagnosis by HCT and MRI were 80% and 66% for extrapancreatic infiltration; 76% and 79% for pancreatic cysts; 87% and 87% for calcifications; and 77% and 92% for atrophy. The diagnostic accuracy for vascular infiltration by HCT and MRI stood at 59% and 77% with sensitivities of 88% and 75%, respectively. Local resectability was correctly determined by HCT in 71%, by MRI in 62% of cases. Lymph node metastases were correctly identified by HCT and MRI with an accuracy of 76% and 72%, while distant metastases were correctly diagnosed by HCT and MRI with an accuracy of 93% and 93%. Correct T stage was identified by HCT in 66%, by MRI in 60%. HCT tended to assign patients to a higher T stage than later determined by surgery and/or histology. CONCLUSION: Our data do not indicate a clear superiority for either HCT or MRI in the diagnosis of pancreatic malignancies.

Use of magnetic resonance imaging to detect neoplastic meningitis: limited use in leukemia and lymphoma but convincing results in solid tumors.

BACKGROUND: An early diagnosis of meningitis is important to improve patients' survival. Data about a direct comparison of cerebrospinal fluid cytology (CSF-cytology) and MRI are very limited. Therefore, the aim of this study was to compare these two diagnostic modalities in diagnosing meningitis in patients with hematopoietic and solid malignancies. METHODS: In 68 patients suspicious for neoplastic meningitis, cytology and MRI (1.5 T) was performed. The meningeal, pial or intraparenchymal hyperintense signal or contrast enhancement was correlated to the final CNS diagnosis and to cytology. RESULTS: 44 patients (64.7%) had neoplastic meningitis, 21 patients (30.9%) had non-neoplastic meningitis. The sensitivity to diagnose meningeal disease was 49.2% for MRI and 95.4% for cytology (p<0.001). In patients with neoplastic meningitis, sensitivity was 45.5% for MRI and 93.2% for cytology (p<0.001). In patients with infectious meningitis, sensitivity was 57.1% for MRI and 100% for cytology (p=0.0013). In patients with solid tumors, the sensitivity was 84.6% for both diagnostic methods. The sensitivity for MRI was low in patients with leukemia (20.0%) and lymphoma (37.5%). The positive predictive value (PPV) for MRI to differentiate infectious from neoplastic meningitis was high in patients with infectious meningitis (75.0%), in patients with lymphoma (83.3%), and in patients with solid tumors (72.7%). Ppv was low in patients with leukemia (33.3%). CONCLUSION: Diagnostic value of MRI for diagnosing meningitis is especially limited in patients with hematopoietic malignancies. MRI better detected leptomeningeal involvement caused by solid tumors than by leukemia or lymphoma. The ppv to specify neoplastic meningitis depends on tumor subtype.