The value of qualitative and quantitative assessment of lesion to cerebral cortex signal ratio on double inversion recovery sequence in the differentiation of demyelinating plaques from non-specific T2 hyperintensities.

OBJECTIVES: To assess the usefulness of the visual assessment and to determine diagnostic value of the lesion-to-cerebral cortex signal ratio (LCSR) measurement in the differentiation of demyelinating plaques and non-specific T2 hyperintensities on double inversion recovery (DIR) sequence. MATERIAL AND METHODS: DIR and fluid-attenuated inversion recovery (FLAIR) sequences of 25 clinically diagnosed multiple sclerosis (MS) patients and 25 non-MS patients with non-specific T2-hyperintense lesions were evaluated visually and LCSRs were measured by two observers independently. RESULTS: On DIR sequence, the calculated mean LCSR ± SD for demyelinating plaques and non-specific T2-hyperintense lesions were 1.60 ± 0.26 and 0.75 ± 0.19 for observer1, and 1.61 ± 0.27 and 0.74 ± 0.19 for observer2. LCSRs of demyelinating plaques were significantly higher than other non-specific T2-hyperintense lesions on DIR sequence. By using the visual assessment demyelinating plaques were differentiated from non-specific T2-hyperintensities with 92.8 % sensitivity, 97.5 % specificity and 95.1 % accuracy for observer1 and 92.8 % sensitivity, 95 % specificity and 93.9 % accuracy for observer2. CONCLUSION: Visual assessment and LCSR measurement on DIR sequence seems to be useful for differentiating demyelinating MS plaques from supratentorial non-specific T2 hyperintensities. This feature can be used for diagnosis of MS particularly in patients with only supratentorial T2-hyperintense lesions who are categorized as radiologically possible MS. KEY POINTS: • Demyelinating plaques and non-specific T2-hyperintensities have different SI on DIR images. • These differences can be assessed by LCSR measurement or visual assessment. • There is an excellent inter-observer agreement for both methods. • This feature can be used in radiologically possible MS cases.

Brain herniations into the dural venous sinus or calvarium: MRI findings, possible causes and clinical significance.

OBJECTIVES: To determine frequency, imaging features and clinical significance of herniations of brain parenchyma into dural venous sinuses (DVS) and/or calvarium found on MRI. METHODS: A total of 6160 brain MRI examinations containing at least one high-resolution T1- or T2-weighted sequence were retrospectively evaluated to determine the presence of incidental brain herniations into the DVS or calvarium. MRI sequences available for review were evaluated according to their capability to demonstrate these herniations. Patients' symptoms and clinical findings were recorded. RESULTS: Twenty-one (0.32 %) brain parenchyma herniations into the DVS (n = 18) or calvarium (n = 3) in 20 patients were detected. The most common locations of the herniations were the transverse sinuses (n = 13) and those involving inferior gyrus of the temporal lobe (n = 9). High-resolution T1- and T2-weighted sequences were equally useful in the detection of these brain herniations. According to clinical symptoms, brain herniations were considered to be incidental but headaches were present in nine patients. CONCLUSION: Brain herniations with surrounding cerebrospinal fluid (CSF) into the DVS and/or calvarium are incidental findings and not proven to be associated with any symptoms. Although rare, these herniations are more common than previously recognized and should not be confused with arachnoid granulations, clots or tumours. KEY POINTS: • Brain herniations into the DVS are more common than previously assumed. • The most frequent locations are the transverse sinus. • These herniations are incidental findings. • The relationship between brain herniation into DVS and headache is uncertain. • High-resolution MR sequences are most useful in detection of brain herniations.

Measures of ventricles and evans' index: from neonate to adolescent.

Ventricle sizes are important for the early diagnosis of hydrocephalus or for follow-up after ventriculostomy. Diameters of ventricles may change, especially in childhood. This study aims to provide normative data about ventricle diameters. Among 14,854 cranial MRI performed between 2011 and 2013, 2,755 images of Turkish children aged 0-18 years were obtained. After exclusions, 517 images were left. Four radiologists were trained by a pediatric radiologist. Twenty images were assessed by all radiologists for a pilot study to see that there was no interobserver variation. There were 10-22 children in each age group. The maximum width of the third ventricle was 5.54 ± 1.29 mm in males in age group 1 and 4.98 ± 1.08 mm in females in age group 2. The Evans' index was <0.3 and consistent with the literature. The third ventricle/basilar artery width ratio was found to be >1 and <2 in all age groups and both gender groups. Our study showed the ventricle size data of children in various age groups from newborn to adolescent. The ventricle volume/cerebral parenchyma ratio seems to decrease with age. We think that these data can be applied in clinical practice, especially for the early diagnosis of hydrocephalus.

Advanced diffusion imaging reveals microstructural characteristics of primary CNS lymphoma, allowing differentiation from glioblastoma.

Background: Primary CNS lymphoma (PCNSL) and glioblastoma (GBM) both represent frequent intracranial malignancies with differing clinical management. However, distinguishing PCNSL from GBM with conventional MRI can be challenging when atypical imaging features are present. We employed advanced dMRI for noninvasive characterization of the microstructure of PCNSL and differentiation from GBM as the most frequent primary brain malignancy. Methods: Multiple dMRI metrics including Diffusion Tensor Imaging, Neurite Orientation Dispersion and Density Imaging, and Diffusion Microstructure Imaging were extracted from the contrast-enhancing tumor component in 10 PCNSL and 10 age-matched GBM on 3T MRI. Imaging findings were correlated with cell density and axonal markers obtained from histopathology. Results: We found significantly increased intra-axonal volume fractions (V-intra and intracellular volume fraction) and microFA in PCNSL compared to GBM (all P < .001). In contrast, mean diffusivity (MD), axial diffusivity (aD), and microADC (all P < .001), and also free water fractions (V-CSF and V-ISO) were significantly lower in PCNSL (all P < .01). Receiver-operating characteristic analysis revealed high predictive values regarding the presence of a PCNSL for MD, aD, microADC, V-intra, ICVF, microFA, V-CSF, and V-ISO (area under the curve [AUC] in all >0.840, highest for MD and ICVF with an AUC of 0.960). Comparative histopathology between PCNSL and GBM revealed a significantly increased cell density in PCNSL and the presence of axonal remnants in a higher proportion of samples. Conclusions: Advanced diffusion imaging enables the characterization of the microstructure of PCNSL and reliably distinguishes PCNSL from GBM. Both imaging and histopathology revealed a relatively increased cell density and a preserved axonal microstructure in PCNSL.

Normal anatomical features and variations of the vertebrobasilar circulation and its branches: an analysis with 64-detector row CT and 3T MR angiographies.

PURPOSE: To determine the normal anatomical features and variations of the vertebrobasilar circulation and its branches in patients who underwent multidetector computed tomography (CT) or magnetic resonance (MR) angiographies of the brain. METHODS: 135 patients (male, 83 and female, 52; mean age, 50.1 years) who underwent CT (n = 71) or MR (n = 64) angiographies of the vertebrobasilar vasculature for various reasons were analyzed retrospectively. The right and left distal vertebral arteries (VAs), posterior inferior cerebellar arteries (PICAs), anterior inferior cerebellar arteries (AICAs), superior cerebellar arteries (SCAs), posterior cerebral arteries (PCAs), and posterior communicating arteries (PCoAs) were analyzed individually. RESULTS: In 24.4% of the cases (33/135) right PICA, in 19.3% of the cases (26/135) left PICA, in 17.8% of the cases (24/135) right AICA, and in 18.5% of the cases (25/135) left AICA were absent. In cases without PICA or AICA, there was a statistically significant, moderately or well-developed AICA or PICA on the same side, respectively (P < 0.001). The most common variation was isolated absence of right PICA and was seen in 17.8% of the cases. CONCLUSIONS: The anatomic features of the branches of the vertebrobasilar circulation may be different from well-known normal anatomy. CT and MR angiographies allow a precise and detailed evaluation of vertebrobasilar circulation.

Mesoscopic Assessment of Microstructure in Glioblastomas and Metastases by Merging Advanced Diffusion Imaging with Immunohistopathology.

BACKGROUND AND PURPOSE: Glioblastomas and metastases are the most common malignant intra-axial brain tumors in adults and can be difficult to distinguish on conventional MR imaging due to similar imaging features. We used advanced diffusion techniques and structural histopathology to distinguish these tumor entities on the basis of microstructural axonal and fibrillar signatures in the contrast-enhancing tumor component. MATERIALS AND METHODS: Contrast-enhancing tumor components were analyzed in 22 glioblastomas and 21 brain metastases on 3T MR imaging using DTI-fractional anisotropy, neurite orientation dispersion and density imaging-orientation dispersion, and diffusion microstructural imaging-micro-fractional anisotropy. Available histopathologic specimens (10 glioblastomas and 9 metastases) were assessed for the presence of axonal structures and scored using 4-level scales for Bielschowsky staining (0: no axonal structures, 1: minimal axonal fragments preserved, 2: decreased axonal density, 3: no axonal loss) and glial fibrillary acid protein expression (0: no glial fibrillary acid protein positivity, 1: limited expression, 2: equivalent to surrounding parenchyma, 3: increased expression). RESULTS: When we compared glioblastomas and metastases, fractional anisotropy was significantly increased and orientation dispersion was decreased in glioblastomas (each P < .001), with a significant shift toward increased glial fibrillary acid protein and Bielschowsky scores. Positive associations of fractional anisotropy and negative associations of orientation dispersion with glial fibrillary acid protein and Bielschowsky scores were revealed, whereas no association between micro-fractional anisotropy with glial fibrillary acid protein and Bielschowsky scores was detected. Receiver operating characteristic curves revealed high predictive values of both fractional anisotropy (area under the curve = 0.8463) and orientation dispersion (area under the curve = 0.8398) regarding the presence of a glioblastoma. CONCLUSIONS: Diffusion imaging fractional anisotropy and orientation dispersion metrics correlated with histopathologic markers of directionality and may serve as imaging biomarkers in contrast-enhancing tumor components.

Sonographic measurement of diuretic-induced renal length changes: are they correlated with renal function?

OBJECTIVES: The purposes of this study were to prospectively identify diuretic-induced renal length changes and to determine whether the percentages of the renal length changes allow estimation of the differential renal function. METHODS: Twenty-three children (14 boys and 9 girls; mean age, 7.83 years) who were undergoing technetium Tc 99m diethylenetriamine pentaacetic acid or technetium Tc 99m mercaptoacetyltriglycine diuretic renography were included in this study. Renal lengths were measured by sonography just before and 15 to 20 minutes after diuretic injection. The Spearman test was used to assess the correlation between renal length increases due to diuretic injection and the differential renal function. RESULTS: The mean renal lengths ± SD measured before and after diuretic administration were 91.52 ± 20.87 and 95.38 ± 21.46 mm, respectively. The increase in renal length after diuretic administration was statistically significant (P < .001). There was a positive correlation between the renal length change and functional status (P = .006). CONCLUSIONS: Renal length may change after diuretic injection according to the functional status, and the sonographic measurements of these changes may be used as an alternative to other imaging methods in estimation of renal function.

The demonstration of the number, course, and the location of nutrient artery canals of the femur by multidetector computed tomography.

PURPOSE: The aim of this study was to evaluate the number, course, width and location of nutrient artery canals of the femur by using multidetector computed tomography (MDCT). METHODS: Sixty-six adult (35 right and 31 left) dry femurs were included in this study and scanned by MDCT. Nutrient artery canals were evaluated on the multi-planar reformatted and volume rendered images which were reproduced on the basis of axial images. RESULTS: The median value of nutrient artery canals was two (minimum 1 and maximum 6). We determined that there was a negative correlation between the number of nutrient canals and the canal diameters. The outer ostia of the nutrient artery canals were most frequently located at the middle third segment of femoral diaphysis (65%). While the vast majority of the canals were showing upward courses (95%), only a few canals were having transverse (3%) or downward (2%) courses. Most encountered location of outer ostia of the canals according to linea aspera was the medial lip of the linea aspera (44%). Various variations were demonstrated in the number, course, and location of nutrient artery canals using MDCT. CONCLUSIONS: In conclusion, the knowledge of the topographic features of the nutrient artery canals may be useful in various clinical implications such as bone grafting or radiologic evaluation for the fracture lines.

Normal anatomical features and variations of bronchial arteries: an analysis with 64-detector-row computed tomographic angiography.

OBJECTIVE: To determine the normal anatomical features and variations of the bronchial arterial system and to determine the relationship among ectopic bronchial arteries, location (right-left) of the bronchial arteries, and variations of the aortic arch in patients as well as the sex of the patients who underwent multidetector computed tomographic angiography of the thorax for various reasons. METHODS: A total of 163 patients who underwent multidetector computed tomographic angiography of the thoracic vascular structures for various reasons were analyzed retrospectively. The right and left bronchial arteries were analyzed individually, and normal anatomic features and variations were recorded. The χ and Mann-Whitney U tests were used to evaluate relationships among the patients' sex, side and number of the bronchial arteries, aortic arch variations, and bronchial artery variations. RESULTS: There were 432 bronchial arteries (right, 229; left, 203) in 163 patients (117 men, 46 women; mean age, 51.7 years). All of the patients have at least one bronchial artery (mean, 2.65; maximum, 5). The number and diameters of the bronchial arteries were statistically higher on the right side. The number of the bronchial arteries was significantly higher in the men (P < 0.05). Ectopic bronchial arteries were present in 43 (26.4%) of the 163 patients. Aortic arch variations were present in 27 (22.5%) of 120 patients with normal bronchial arteries and in 11 (25.6%) of the 43 patients with ectopic bronchial arteries. There was no statistically significant correlation between aortic arch variations and ectopic bronchial arteries (P = 0.861). CONCLUSIONS: The anatomic features of the bronchial arteries show differences between individuals and the sexes. Multidetector computed tomographic angiography allows a precise and detailed evaluation of bronchial arterial system.

Diffusion-weighted imaging in the characterization of focal liver lesions: efficacy of visual assessment.

OBJECTIVES: The objective of the study was to assess the value of visual assessment of signal intensities on b800 diffusion-weighted images and apparent diffusion coefficient (ADC) maps in differentiation of benign and malignant focal liver lesions (FLLs). METHODS: Approval for this retrospective study was obtained from the institutional review board. One hundred forty-three FLLs in 65 patients (38 women, 27 men; mean age, 50.8 years) underwent magnetic resonance (MR) imaging and diffusion-weighted imaging (DWI) with a respiratory-triggered single-shot echo-planar imaging sequence. Focal liver lesions were evaluated visually according to the signal intensities on b800 and ADC map images, and ADC values were also calculated. The conventional MR imaging, follow-up imaging findings, and histopathologic data were regarded as gold standard. Normal distribution was assessed with Kolmogorov-Smirnov test. The accuracies of visual assessment and ADC values in differentiating benign and malignant FLLs were assessed with the Student t test, and threshold values were determined with receiver operating characteristic curve analysis. RESULTS: By using a cutoff value of 1.21 × 10⁻³ mm²/s, ADC had a sensitivity of 100%, a specificity of 89.3%, and an accuracy of 92.3% in the discrimination of malignant FLLs. With the visual assessment of the DWIs and ADC maps, malignant lesions were differentiated from benign ones, with 100% sensitivity, 92.2% specificity, and 94.4% accuracy. Although some benign lesions were interpreted as malignant, no malignant lesion was determined as benign in visual assessment. CONCLUSIONS: Most FLLs are benign ones such as hemangiomas and cysts, which can be readily and practically characterized only by using visual assessment of DWIs without requiring time-consuming conventional and dynamic contrast-enhanced imaging sequences. Some benign lesions that are falsely interpreted as malignant can be further characterized by using conventional and contrast-enhanced MR studies.

Pulmonary artery embolism due to a ruptured hepatic hydatid cyst: clinical and radiologic imaging findings.

Hydatid pulmonary embolism is an uncommon condition resulting from the rupture of a hydatid heart cyst or the opening of a visceral hydatid cyst into the venous circulation. We report a rare case with multiple intra-arterial pulmonary hydatid cyst emboli originating from a hepatic hydatid cyst ruptured into the hepatic segment of the inferior vena cava. We present the ultrasonography findings of hepatic hydatid cyst and multidetector computed tomography pulmonary angiography images demonstrating both multiple hydatid cyst emboli and their hepatic origin.

Diuretic-induced renal length changes in the estimation of renal function with MR urography.

OBJECTIVE: The objective of this study was to evaluate whether administration of a diuretic agent in MR urography has an effect on renal length and to determine whether the increase in length can be used for the assessment of renal function. CONCLUSION: Renal length may change after diuretic injection, and these changes correlate with renal function.

Hiccup as a result of late lead perforation: report of two cases and review of the literature.

Pacemaker (PM) lead perforation is a rare complication with an incidence of <1%. Late lead perforation is defined as the perforation of a device lead through the myocardium more than 1 month after implantation. It is a subcategory of overall lead perforation and it has been described in several case reports. In the current paper, we present two cases with late partial lead perforation developing after the PM implantation.

Obstructive rectal intramural hematoma caused by a foreign body.

Intramural hematoma of the alimentary tract is a rare condition, which usually results from blunt injury. It can spontaneously occur in patients with coagulopathy or on anticoagulants. Although it may be seen anywhere in the alimentary tract, duodenum is the most common site of the intestinal intramural hematomas. Intramural hematoma caused by a foreign body is rarely seen. Patients with intramural hematoma are usually encountered with obstructive symptoms after an isolated injury. Intramural hematomas are often self-limited at the site of occurrence and can be managed conservatively. They rarely cause progressive obstruction and need surgical drainage. In this article, we report a 51-year-old male patient with foreign body used for masturbation causing rectal intramural hematoma and perforation at the rectosigmoid junction. Because of the intestinal perforation, the patient was managed surgically. In the diagnosis of intramural hematoma of the alimentary tract, beside the clinical history and physical examination, the findings at imaging modalities such as conventional radiography, ultrasonography, and computed tomography are often useful. Patients with rectal intramural hematoma usually do not give diagnostic clues to the physicians in the clinical history. Therefore, radiologists must be familiar with the imaging findings. In this article, we aimed to present a patient with rectal intramural hematoma caused by foreign body and obliterating the rectal lumen.