Modified Dynamic CT Myelography for Type 1 and 2 CSF Leaks: A Procedural Approach.

BACKGROUND AND PURPOSE: Dynamic CT myelography can identify spinal CSF leaks secondary to dural tears (type 1) and ruptured meningeal diverticula (type 2), but the radiation can be high secondary to multiple successive acquisitions. The purpose of this article is to discuss the procedural approach of a modified dynamic CT myelography technique with single scan acquisitions, reduced contrast volume, and condensed scan coverage and compare its radiation dose with that in traditional dynamic CT myelography. MATERIALS AND METHODS: Retrospective review was performed for patients with spontaneous CSF leaks showing extradural collections on spine MR imaging who underwent traditional and modified dynamic CT myelography. The radiation doses between the 2 cohorts were compared. RESULTS: Thirty-seven patients (25 women, 12 men) had a type 1 or 2 CSF leak on dynamic CT myelography. Thirty-one patients had a type 1 CSF leak, and 6 patients had type 2 leaks. The traditional dynamic CT myelography was performed in 25 patients, and the average number of acquisitions per dynamic CT myelography was 3.6. The mean total effective dose per dynamic CT myelography was 31.3 mSv (range, 11.3-68.4 mSv). The modified dynamic CT myelography was performed in 12 patients, and the average number of acquisitions was 2.8. The mean total effective dose per dynamic CT myelography was 15.1 mSv (range, 4.8-24.6 mSv). The effective dose and dose-length product between the cohorts were statistically significant (P < .0001 and .01, respectively). CONCLUSIONS: Modified dynamic CT myelography performed with single scan acquisitions, smaller volume of contrast, and reduced scan coverage can reduce the radiation dose for type 1 and 2 CSF leak detection.

Spontaneous Spinal CSF Leaks Stratified by Age, Body Mass Index, and Spinal Level.

BACKGROUND AND PURPOSE: There are 3 main types of spinal CSF leaks, and the imaging appearances are well-reported. Specific patient demographics and spinal locations of the various types of spinal leaks are less frequently described. The purpose of this article was to stratify the various types of spontaneous CSF leaks on the basis of age, body mass index, and spinal level. MATERIALS AND METHODS: Retrospective review was performed for all patients with spontaneous spinal CSF leaks identified on CT myelography. Age, body mass index, and spinal CSF leak type and level were recorded. RESULTS: Sixty-five patients (37 women and 28 men) had spinal CSF leaks. Type 1 CSF leaks (dural tears) were observed in 25 patients (mean age, 44.5 years; mean body mass index, 24.3) and were most common in the upper thoracic spine (72%), particularly at the T1-T2 level (36%). Type 2 CSF leaks (ruptured meningeal diverticula) were observed in 4 patients (mean age, 45.5 years; mean body mass index, 27.5) and were all seen in the lower thoracic spine. Type 3 CSF leaks (CSF-venous fistulas) were observed in 36 patients (mean age, 58.8 years; mean body mass index, 27.0) and were most common on the right side (72%) and in the lower thoracic spine (56%). CONCLUSIONS: Type 1 CSF leaks occurred in younger patients with a normal body mass index, while patients with type 3 CSF leaks were relatively older and had an elevated body mass index. Type 1 leaks mostly occurred in the upper thoracic spine, and types 2 and 3 leaks mostly occurred in the lower thoracic spine.

Prenatal Diagnosis of Third and Fourth Branchial Apparatus Anomalies: Case Series and Comparison with Lymphatic Malformation.

BACKGROUND AND PURPOSE: Third and fourth branchial apparatus anomalies are rare congenital anomalies. The purpose of this study was to investigate imaging features of these lesions on fetal MR imaging in comparison with lymphatic malformations, the major competing differential diagnosis in these cases. MATERIALS AND METHODS: A retrospective review of our institutional fetal MR imaging database between 1997 and 2019 resulted in 4 patients with confirmed third and fourth branchial apparatus anomalies and 14 patients with confirmed lymphatic malformations. The imaging features were reviewed by consensus, and the Fisher exact test was used to evaluate statistically significant differences between these 2 populations. RESULTS: Four cases of third and fourth branchial apparatus anomalies were imaged at 29 weeks 1 day (range, 23 weeks 1 day to 33 weeks 4 days). All 4 cases demonstrated unilateral, unilocular cysts without reduced diffusion or hemorrhage and a medially directed beaked contour that tapered between the spine and airway at the level of the piriform sinus. Compared with 14 cases of fetal lymphatic malformations imaged at 27 weeks 6 days (range, 21 weeks 3 days to 34 weeks 6 days), third and fourth branchial apparatus cysts were significantly more likely to be unilocular (P < .005) and to have a medially beaked contour (P < .005). The combination of features of unilateral, unilocular, and medially beaked contour was observed only in the fetuses with third and fourth branchial apparatus cysts (P < .001). CONCLUSIONS: The presence of a left-sided unilocular cyst with a medially beaked contour tapering at the level of the piriform sinus suggests the diagnosis of third and fourth branchial apparatus anomaly. Accurate diagnosis in the prenatal period allows proper counseling, genetic work-up, and treatment, potentially sparing patients from recurrent infections and associated morbidity.

Decubitus CT Myelography for CSF-Venous Fistulas: A Procedural Approach.

Decubitus CT myelography is a reported method to identify CSF-venous fistulas in patients with spontaneous intracranial hypotension. One of the main advantages of decubitus CT myelography in detecting CSF-venous fistulas is using gravity to dependently opacify the CSF-venous fistula, which can be missed on traditional myelographic techniques. Most of the CSF-venous fistulas in the literature have been identified in patients receiving general anesthesia and digital subtraction myelography, a technique that is not performed at all institutions. In this article, we discuss the decubitus CT myelography technique and how to implement it in daily practice.

Arterial Spin-Labeling Perfusion for PHACE Syndrome.

BACKGROUND AND PURPOSE: Arterial stroke is a rare-but-reported complication in patients with posterior fossa brain malformations, hemangiomas, arterial anomalies, coarctation of the aorta and cardiac defects, and eye abnormalities (PHACE) syndrome. Currently, stroke risk is inferred by the severity of arterial anomalies identified on MRA, though no evidenced-based data exist. The purpose of our study was to determine whether arterial spin-labeling MR imaging perfusion can detect alterations in CBF in patients with PHACE syndrome. MATERIALS AND METHODS: Records were reviewed from 3 institutions for all patients with PHACE syndrome who underwent arterial spin-labeling from 2000 to 2019. CBF was qualitatively investigated with arterial spin-labeling to determine whether there was decreased or normal perfusion. Arterial anomalies were characterized on MRA imaging, and parenchymal brain findings were evaluated on conventional MR imaging sequences. RESULTS: Forty-one patients with PHACE syndrome had arterial spin-labeling imaging. There were 30 females and 11 males (age range, 7 days to 15 years). Of the 41 patients, 10 (24%) had decreased CBF signal corresponding to a major arterial territory. Ten of 10 patients had decreased CBF signal in the anterior circulation, 2/10 had decreased anterior and posterior circulation CBF signal, 2/10 had decreased bilateral anterior circulation CBF signal, and 1/10 had globally decreased CBF signal. Forty of 41 (97.5%) patients had at least 1 arteriopathy, and in those with decreased CBF signal, the arteriopathy corresponded to the CBF signal alteration in 10/10 patients. CONCLUSIONS: Arterial spin-labeling can potentially characterize hemodynamic changes in patients with PHACE syndrome.

Contextual Radiology Reporting: A New Approach to Neuroradiology Structured Templates.

Structured reporting has many advantages over conventional narrative reporting and has been advocated for standard usage by radiologic societies and literature. Traditional structured reports though are often not tailored to the appropriate clinical situation, are generic, and can be overly constraining. Contextual reporting is an alternative method of structured reporting that is specifically related to the disease or examination indication. Herein, we create a library of 50 contextual structured reports for neuroradiologists and emphasize their clinical value over noncontextual structured reporting. These templates are located in the On-line Appendix, and a downloadable PowerScribe 360 file may be accessed at https://drive.google.com/open?id=1AlPUmfAXPzjkMFcHf7vGKF4Q-vIdpflT.

MRI Atlas-Based Measurement of Spinal Cord Injury Predicts Outcome in Acute Flaccid Myelitis.

BACKGROUND AND PURPOSE: Recent advances in spinal cord imaging analysis have led to the development of a robust anatomic template and atlas incorporated into an open-source platform referred to as the Spinal Cord Toolbox. Using the Spinal Cord Toolbox, we sought to correlate measures of GM, WM, and cross-sectional area pathology on T2 MR imaging with motor disability in patients with acute flaccid myelitis. MATERIALS AND METHODS: Spinal cord imaging for 9 patients with acute flaccid myelitis was analyzed by using the Spinal Cord Toolbox. A semiautomated pipeline using the Spinal Cord Toolbox measured lesion involvement in GM, WM, and total spinal cord cross-sectional area. Proportions of GM, WM, and cross-sectional area affected by T2 hyperintensity were calculated across 3 ROIs: 1) center axial section of lesion; 2) full lesion segment; and 3) full cord atlas volume. Spearman rank order correlation was calculated to compare MR metrics with clinical measures of disability. RESULTS: Proportion of GM metrics at the center axial section significantly correlated with measures of motor impairment upon admission (r [9] = -0.78; P = .014) and at 3-month follow-up (r [9] = -0.66; P = .05). Further, proportion of GM extracted across the full lesion segment significantly correlated with initial motor impairment (r [9] = -0.74, P = .024). No significant correlation was found for proportion of WM or proportion of cross-sectional area with clinical disability. CONCLUSIONS: Atlas-based measures of proportion of GM T2 signal abnormality measured on a single axial MR imaging section and across the full lesion segment correlate with motor impairment and outcome in patients with acute flaccid myelitis. This is the first atlas-based study to correlate clinical outcomes with segmented measures of T2 signal abnormality in the spinal cord.

Direct Cranial Nerve Involvement by Gliomas: Case Series and Review of the Literature.

Malignant gliomas are characterized by infiltrative growth of tumor cells, including along white matter tracts. This may result in clinical cranial neuropathy due to direct involvement of a cranial nerve rather than by leptomeningeal spread along cranial nerves. Gliomas directly involving cranial nerves III-XII are rare, with only 11 cases reported in the literature before 2014, including 8 with imaging. We present 8 additional cases demonstrating direct infiltration of a cranial nerve by a glioma. Asymmetric cisternal nerve expansion compared with the contralateral nerve was noted with a mean length of involvement of 9.4 mm. Based on our case series, the key imaging feature for recognizing direct cranial nerve involvement by a glioma is the detection of an intra-axial mass in the pons or midbrain that is directly associated with expansion, signal abnormality, and/or enhancement of the adjacent cranial nerves.

Paediatric parotid neoplasms: a 10 year retrospective imaging and pathology review of these rare tumours.

AIM: To determine the relative incidence of benign and malignant paediatric parotid gland tumours and whether particular presenting symptoms or imaging characteristics were more likely to predict malignancy. MATERIALS AND METHODS: Hospital records were reviewed for all patients <18 years with histopathology-proven parotid neoplasms over the 10 year period from 2003-2013. Infantile haemangiomas and patients with neurofibromatosis type I were excluded. The presenting clinical symptoms for each patient were recorded. All available CT and MRI examinations for these patients were evaluated for tumour imaging characteristics. RESULTS: Seventeen patients (nine boys, eight girls; age range 2-17 years) were identified with neoplastic parotid masses; 11 tumours were malignant (65%) and six were benign (35%). The malignant tumours consisted of three acinic cell carcinomas, two mucoepidermoid carcinomas, one alveolar rhabdomyosarcoma, one poorly differentiated carcinoma, one low-grade adenocarcinoma, and three metastases (two melanoma, one orbital medulloepithelioma). The benign tumours consisted of five pleomorphic adenomas and one schwannoma. Presenting clinical symptoms were similar between benign and malignant tumours. Twelve MRI and six CT examinations were available for review with five patients undergoing both techniques. MRI features commonly identified with malignant tumours included: hypointense T2 signal, restricted diffusion, ill-defined borders, and focal necrosis. Only four of the six tumours imaged at CT were visualized, and of those, the margins were indeterminate in three patients. CONCLUSION: Paediatric parotid masses are more likely to be malignant than benign. Presenting clinical symptoms and CT are not helpful for distinguishing benign and malignant disease. MRI features such as T2 hypointensity, restricted diffusion, ill-defined borders, and focal necrosis, although not specific, should raise concern for malignancy.

Neuroimaging findings of the post-treatment effects of radiation and chemotherapy of malignant primary glial neoplasms.

Post-treatment radiation and chemotherapy of malignant primary glial neoplasms present a wide spectrum of tumor appearances and treatment-related entities. Radiologic findings of these post-treatment effects overlap, making it difficult to distinguish treatment response and failure. The purposes of this article are to illustrate and contrast the imaging appearances of recurrent tumor from necrosis and to discuss other radiologic effects of cancer treatments. It is critical for radiologists to recognize these treatment-related effects to help direct clinical management.

Cerebral thromboembolism: value of susceptibility-weighted imaging in the initial diagnosis of acute infarction.

Susceptibility-weighted imaging (SWI) is commonly used to diagnose cerebral hemorrhage, calcification, and other T2* lesions. Its role in the detection of cerebral thromboemboli has been suggested for emboli of the anterior division of the middle cerebral artery (MCA). The purpose of our study was to determine SWI's accuracy and sensitivity in detection of all sites of cerebral thromboemboli, not just MCA emboli. Two neuroradiologists retrospectively reviewed consecutive MRI brain examinations with SWI for cerebral thromboemboli in 100 patients with clinical suspicion for stroke determined by the NIH Stroke Scale (NIHSS) score. FLAIR, MRA, CT, and catheter angiography were reviewed for thromboemboli in the same patients. Thromboembolic sites included: the internal carotid artery (ICA) terminus, anterior MCA, posterior MCA, any other cerebral artery, or if not present. The exclusion criteria included: no magnetic resonance angiogram (MRA) or catheter angiogram for comparison, lack of restricted diffusion, lacunar infarcts, and the presence of massive hemorrhage. The accuracy, sensitivity, and specificity of each imaging modality were determined. Twenty-four patients were excluded based on the aforementioned criteria. Cerebral thromboemboli were identified in 35 of the remaining 76 patients. Of the 35 patients with thromboemboli, 30 were identified on SWI. FLAIR detected 22/35 emboli, MRA 30/33, CT 18/35, and catheter angiography 12/12. The accuracies for SWI, FLAIR, and CT were 97%, 84%, and 74%, respectively. The sensitivities for SWI, FLAIR, and CT were 85%, 61%, and 52%, respectively. The specificities for SWI, FLAIR, and CT were 100%, 98%, and 93%, respectively. There is an adjunctive role of SWI to identify cerebral thromboemboli in patients with acute infarction. SWI is superior to FLAIR and CT, and complementary to MRA and catheter angiography in emboli detection. This study supports SWI detection of MCA emboli, but also emphasizes its utility in emboli detection of other arteries based on a high accuracy and sensitivity.