Advanced MRI features of intraventricular inflammatory myofibroblastic tumor: a case report.

BACKGROUND: Inflammatory myofibroblastic tumor (IMT) is a rare central nervous system (CNS) tumor. We first report a rare case of IMT in the lateral ventricle and describe the magnetic resonance imaging (MRI) findings of the tumor with an emphasis on the advanced MRI features. CASE PRESENTATION: A 49-year-old female patient with headaches and blurred vision for 2 months. Brain MRI revealed a well-circumscribed, lobulated mass occupying the left lateral ventricle trigone, with marked perilesional brain edema. The tumor showed heterogeneous significant hyperintensity on T2-weighted imaging (T2WI) and hypointensity on T1-weighted imaging (T1WI). After the administration of gadolinium, the mass exhibited marked contrast enhancement and the halo sign was observed. On advanced MRI, the lesion showed decreased perfusion on perfusion MRI and reduced diffusion on diffusion-weighted imaging (DWI). On susceptibility-weighted imaging (SWI), there was a punctate low signal intensity in the tumor. The patient underwent surgical resection of the mass and a pathological examination confirmed the lesion to be an inflammatory myofibroblastic tumor with negative expression of anaplastic lymphoma kinase (ALK). This patient had remained healthy without evidence of recurrence during a 20-month follow-up. CONCLUSIONS: On MRI, marked perilesional brain edema, significant hyperintensity on T2WI, hypoperfusion on perfusion MRI but with an obvious enhancement, no diffusion restriction on DWI, and halo sign may be the characteristic findings of intraventricular IMT. The advanced MRI characteristics could provide abundant information to reflect the histological features and physiological metabolic characteristics of the tumor.

Fatal noncardiogenic pulmonary edema related to nonionic, iso-osmolar iodine contrast medium: one case report.

BACKGROUND: Noncardiogenic pulmonary edema (NCPE) is a rare and life-threatening allergy-like reaction to the intravascular injection of a nonionic radiographic agent. We first describe a very rare case of fatal NCPE after the intravenous injection of nonionic, iso-osmolar iodine contrast media. Case presentation A 55-year-old male patient was admitted to the hospital with esophageal cancer. After the intravenous administration of 100 mL iodixanol, the patient first exhibited digestive tract symptoms, including abdominal pain, diarrhea, and vomiting, with no dyspnea, rash, itching, or throat edema. He received anti-allergy treatment, but his symptoms did not improve; instead, he further developed pulmonary edema. Arterial blood gas analysis results were as follows: pH, 7.08; PO2, 70 mm Hg; PCO2, 40 mm Hg; and SaO2, 52%. Then, the patient received emergent tracheal intubation and ventilation to assist breathing, and he was transferred to the intensive care unit (ICU) for further treatment. In the ICU, the patient developed shock and respiratory and circulatory failure; therefore, he received shock resuscitation, acidosis correction, muscle relaxants to lower the work of breathing, and cardiotonic therapy. The patient eventually died. During the ICU period, emergency bedside color ultrasound showed a diffuse B line in both lungs, and the size of the cardiac cavity was normal, but the ventricular rate was extremely fast. Chest radiography showed pulmonary edema with a normal cardiac silhouette, and the brain natriuretic peptide (BNP) level was in the normal range. CONCLUSIONS: NCPE is a rare and critical allergy-like reaction to the use of a nonionic iso-osmolar radiocontrast contrast medium. Clinicians should pay very close attention to digestive tract manifestations during the medical observation of patients, as gastrointestinal manifestations may be the prodromal symptoms of NCPE caused by iso-osmolar contrast medium injection.

Myofibroma/myofibromatosis: MDCT and MR imaging findings in 24 patients with radiological-pathological correlation.

BACKGROUND: The aim of this study was to characterize the radiological features of myofibroma on multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) and correlate the imaging findings with pathologic features. METHODS: The radiological findings of 24 patients with 29 myofibromas were retrospectively reviewed. All images were evaluated with emphasis on density, signal intensity, hypointense area, and enhancement, correlating these with pathologic findings. RESULTS: On plain MDCT scan, 4(26.7%) tumors were homogeneous isodensity, 4(26.7%) tumors were heterogeneous hyperdensity, and 7(46.7%) tumors were heterogeneous hypodensity. On contrast-enhanced MDCT scan, all tumors (9/9) showed heterogeneous enhancement with moderate in 3(33.3%) and marked in 6(66.7%) tumors, and their enhancements were higher compared to adjacent skeletal muscle (P = 0.0001). On MRI, heterogeneous slight hyperintensity, homogeneous slight hyperintensity, and heterogeneous hypointensity on T1-weighted imaging (T1WI) were observed in 14(82.3%), 1(5.9%) and 2(11.8%) tumors, respectively. On T2-weighted imaging (T2WI) and fat-suppressed (FS) T2WI, all tumors demonstrated heterogeneous hyperintensity. All tumors showed heterogeneous marked enhancement on FS contrast-enhanced T1WI. On T1WI, T2WI, FS T2WI, and FS contrast-enhanced T1WI, irregular strip or/and patchy hypointensities were found in 16(94.1%), 12(100%), 17(100%) and 17(100%) tumors, respectively, and pseudocapsule was seen in 5(29.4%) tumors. The hypointensities and pseudocapsule on MRI were exactly corresponding to pathological interlacing collagen fibers and fibrosis. The age of the recurrent group was lower than that of the non-recurrent group (P = 0.001) and the tumors without pseudocapsule were more likely to recur than those with pseudocapsule (P = 0.034). CONCLUSION: Myofibromas are characterized by heterogeneous density or signal intensity, with moderate or marked enhancement. The hypointensities and pseudocapsule on MRI may be helpful in diagnosis, and the absence of pseudocapsule and younger age may be risk factors for tumor recurrence.

Relationship of superior mesenteric artery thrombus density with transmural intestinal necrosis on multidetector computed tomography in acute mesenteric ischemia.

BACKGROUND: Acute arterial occlusive mesenteric ischemia with transmural intestinal necrosis (TIN) is a fatal disease, which is difficult to diagnose on multidetector computed tomography (MDCT). The aim of the present study was to determine the relationship of superior mesenteric artery (SMA) thrombus density with TIN on MDCT in patients with acute mesenteric ischemia (AMI) due to SMA thromboembolism. METHODS: In this retrospective study, 33 patients who underwent abdominal MDCT and angiography for AMI due to SMA thromboembolism were divided into two groups: the AMI with TIN group and the AMI without TIN group. We analyzed the relationships of clinical characteristics, qualitative MDCT signs, and SMA thrombus density with TIN. The SMA thrombus density was measured on non-contrast MDCT. Univariate and multivariate analyses were performed to determine the risk factors for predicting TIN. The diagnostic performances of risk factors were evaluated by receiver-operating characteristic (ROC) curve analysis. RESULTS: Of the patients with AMI enrolled in this study, 33.3% (11/33) were diagnosed with TIN. Peritonitis (P=0.042), bowel wall thinning (P=0.033), and pneumatosis/portomesenteric gas (P=0.010) were significantly associated with TIN. AMI patients with TIN exhibited a higher SMA thrombus density than AMI patients without TIN [41.2±6.1 vs. 34.2±3.0 Hounsfield unit (HU), P=0.003]. Multivariate analysis showed that SMA thrombus density was an independent predictor of TIN [P=0.044, hazard ratio (HR): 1.82, 95% confidence interval (CI): 1.02-3.25]. For diagnosing AMI with TIN, the area under the ROC curve (AUC) of SMA thrombus density (0.83) was larger than those of peritonitis (0.68), bowel wall thinning (0.66), and pneumatosis/portomesenteric gas (0.71). CONCLUSIONS: In patients with AMI, erythrocyte-rich thrombus blocking the SMA trunk which has a higher density on MDCT is prone to the occurrence of TIN compared with erythrocyte-scarce thrombus with a lower density. SMA thrombus density could be an independent risk factor for TIN in patients with AMI due to SMA thromboembolism.

Pilomatricoma (calcifying epithelioma): MDCT and MR imaging findings in 31 patients with radiological-pathological correlation.

PURPOSE: To describe the radiological characteristics of pilomatricomas on multi-detector computed tomography (MDCT) and magnetic resonance imaging (MRI), and to correlate the radiological findings and pathological features. MATERIALS AND METHODS: The radiological findings of 41 pilomatricomas in 31 patients were retrospectively reviewed. The images were evaluated with emphasis on calcifications, reticular and ring-like appearances, enhancement patterns, circular target sign and peritumoral fat stranding, and correlating these with pathological features. RESULTS: Of the 31 lesions evaluated by MDCT, 25(80.6%) showed different patterns of calcifications which included single in 12(38.7%) lesions and multiple in 13(41.9%) lesions, but peritumoral fat stranding was observed only in 2(6.5%) lesions. MRI scans were performed in 11 patients with 21 lesions, homogeneous and inhomogeneous hypointensities on T1-weighted (T1W) images were showed respectively in 14(66.7%) and 7(33.3%) lesions. On fat-suppressed (FS) T2-weighted (T2W) images, a ring-like hyperintensity was observed in all 21(100%) lesions, reticular hyperintensity, circular target sign, peritumoral fat stranding and secondary anetoderma were seen in 7(33.3%), 4(19%), 4(19%) and 1(4.8%) lesions, respectively; and a significant difference (P < 0.05) was found when comparing the maximum diameter of tumors with (2.3 ± 1.4 mm) and without (1.1 ± 0.3 mm) reticular hyperintensity. On contrast-enhanced T1W images, all 21(100%) lesions were found to have ring-like enhancement and 7(33.3%) of them showed reticular enhancement. The reticular and ring-like appearances on MR images respectively corresponded to the pathological edematous stroma and connective tissue capsule, and the four-layer structures of the circular target sign on FS T2W images also corresponded to pathological calcifications, shadow cells, epithelial cells and connective tissue capsule, respectively. CONCLUSIONS: The characteristic radiological findings associated with pilomatricomas include different patterns of calcifications on MDCT images and ring-like, reticular appearances and circular target sign on MR images. Radiological findings are well correlated with pathological nature.