Lubdha M. Shah

Imaging of Spinal Metastatic Disease

Metastases to the spine can involve the bone, epidural space, leptomeninges, and spinal cord. The spine is the third most common site for metastatic disease, following the lung and the liver. Approximately 60–70% of patients with systemic cancer will have spinal metastasis. Materials/Methods. This is a review of the imaging techniques and typical imaging appearances of spinal metastatic disease. Conclusions. Awareness of the different manifestations of spinal metastatic disease is essential as the spine is the most common site of osseous metastatic disease. Imaging modalities have complimentary roles in the evaluation of spinal metastatic disease. CT best delineates osseous integrity, while MRI is better at assessing soft tissue involvement. Physiologic properties, particularly in treated disease, can be evaluated with other imaging modalities such as FDG PET and advanced MRI sequences. Imaging plays a fundamental role in not only diagnosis but also treatment planning of spinal metastatic disease.

MRI of Spinal Bone Marrow: Part 2, T1-Weighted Imaging-Based Differential Diagnosis

OBJECTIVE The purpose of this article is to review the structure of bone marrow and the differential diagnosis of bone marrow pathology on the basis of T1-weighted MRI patterns. CONCLUSION Bone marrow is an organ that is evaluated routinely during MRI of the spine, particularly lumbar spine evaluation. Thus, it is one of the most commonly performed MRI examinations. T1-weighted MRI is a fundamental sequence in evaluating spinal marrow, and an understanding of T1-weighted MR signal abnormalities is important for the practicing radiologist.

MRI of Spinal Bone Marrow: Part 1, Techniques and Normal Age-Related Appearances

OBJECTIVE This article reviews MRI protocols, including routine and nonroutine pulse sequences as well as the normal MRI appearance of spinal marrow and expected age-related changes. CONCLUSION Routine MRI of the spine provides useful evaluation of the spinal bone marrow, but nonroutine MRI pulse sequences are increasingly being used to evaluate bone marrow pathology. An understanding of MRI pulse sequences and the normal and age-related appearances of bone marrow is important for the practicing radiologist.

Posterior reversible encephalopathy syndrome with spinal cord involvement

Objective: To characterize a cohort of patients with the signs and symptoms of posterior reversible encephalopathy syndrome (PRES), but with clinical and radiologic involvement of the spinal cord. Methods: We report 2 cases of PRES with spinal cord involvement and identified an additional 6 cases in the Medline database using various search terms related to “spinal PRES,” “spinal reversible posterior leukoencephalopathy syndrome,” and “spinal hypertensive encephalopathy.” We analyzed the clinical and imaging characteristics of the 8 cases. Results: Average age was 31 years, with 5 male and 3 female patients. All patients had severe acute hypertension and a confluent, expansile central spinal cord T2 hyperintensity spanning at least 4 spinal segments, originating at the cervicomedullary junction. Of 8 patients, 7 had hypertensive retinopathy, a favorable clinical course with only antihypertensive treatment, and resolution of the spinal cord lesions on follow-up imaging. A total of 4 of 8 patients had symptoms referable to the spinal cord lesions and only 1 of 8 had a seizure. Conclusion: In light of the already wide definition of PRES, we propose a new syndrome named PRES with spinal cord involvement (PRES-SCI). Clinicians should suspect PRES-SCI when patients with PRES have neurologic signs referable to the spinal cord, extreme elevation in blood pressure, MRI lesions that extend to the cervicomedullary junction, or grade IV hypertensive retinopathy. These clinical scenarios should prompt a cervical spine MRI to help guide patient management decisions and prognostication. When clinicians evaluate longitudinally extensive spinal T2 hyperintensities, they should consider PRES-SCI, which, if diagnosed, would spare patients the morbidity of a standard myelitis workup and empiric treatment.

Calcified Cerebral Emboli, A “Do Not Miss” Imaging Diagnosis: 22 New Cases and Review of the Literature

The prevalence, imaging appearance, presumed source, treatment, and outcome of patients with calcified cerebral emboli on CT were assessed in 22 cases seen by the authors and in 48 from the literature. Most calcified emboli were found in the middle cerebral artery territory and were thought to arise from the heart, aortic arch, or carotid plaques. The overall prevalence of these emboli was 2.7% with 27% initially misdiagnosed and 9% overlooked on the first interpretation. BACKGROUND AND PURPOSE: Calcified cerebral emboli are a rarely reported but devastating cause of stroke and may be the first manifestation of vascular or cardiac disease. Our aim was to evaluate the diagnosis, prevalence, imaging appearance, presumed embolic source, treatment, and outcome of patients with calcified cerebral emboli. MATERIALS AND METHODS: Our radiology information system was searched for all CT scans by using keywords “calcified,” “emboli,” and their permutations. The radiology information system was also searched to identify all “stroke” CT reports to calculate the prevalence of calcified cerebral emboli. We also performed a MEDLINE search to identify all published case reports. RESULTS: Twenty-two cases were identified from our database, and 48 were cases reported from the literature. The middle cerebral artery was the site of 83% of calcified emboli. Presumed sources were calcific aortic stenosis (36%), carotid atherosclerotic plaque (30%), and mitral annular calcification (11%). Spontaneous embolism occurred in 86%. Surgical treatment was performed in 34% of patients. Sixty-four percent of the patients with calcified aortic stenosis underwent aortic valve replacement. Among those with identifiable arterial disease, 53% underwent endarterectomy. Forty-one percent of patients experienced at least 1 recurrent stroke. The prevalence of calcified cerebral emboli identified on stroke CT scans at our institution was 2.7%. Seventy-three percent of cases were correctly identified. Twenty-seven percent were misdiagnosed on initial interpretation, while 9% were overlooked on preliminary interpretation. CONCLUSIONS: Calcified cerebral emboli are more common than previously assumed, are frequently overlooked or misinterpreted, affect clinical course when diagnosed, and carry substantial risk for recurrent stroke.

Reliability and reproducibility of individual differences in functional connectivity acquired during task and resting state.

Application of fMRI connectivity metrics as diagnostic biomarkers at the individual level will require reliability, sensitivity and specificity to longitudinal changes in development, aging, neurocognitive, and behavioral performance and pathologies. Such metrics have not been well characterized for recent advances in BOLD acquisition.

Carotid Body Detection on CT Angiography

BACKGROUND AND PURPOSE: Advances in multidetector CT provide exquisite detail with improved delineation of the normal anatomic structures in the head and neck. The carotid body is 1 structure that is now routinely depicted with this new imaging technique. An understanding of the size range of the normal carotid body will allow the radiologist to distinguish patients with prominent normal carotid bodies from those who have a small carotid body paraganglioma. MATERIALS AND METHODS: We performed a retrospective analysis of 180 CTAs to assess the imaging appearance of the normal carotid body in its expected anatomic location. RESULTS: The carotid body was detected in >80% of carotid bifurcations. The normal size range measured from 1.1 to 3.9 mm ± 2 SDs, which is consistent with the reported values from anatomic dissections. CONCLUSIONS: An ovoid avidly enhancing structure at the inferomedial aspect of the carotid bifurcation within the above range should be considered a normal carotid body. When the carotid body measures >6 mm, a small carotid body paraganglioma should be suspected and further evaluated.

Intracranial Hypotension: Improved MRI Detection With Diagnostic Intracranial Angles

OBJECTIVE Intracranial hypotension is an uncommon cause of headaches that is often misdiagnosed. The classic MRI features of intracranial hypotension can be variable and subjective. The purpose of this study was to provide objective criteria in the MRI evaluation of intracranial hypotension by quantifying normal values for the pontomesencephalic angle, mamillopontine distance, and lateral ventricular angle. MATERIALS AND METHODS A retrospective review of patients with the clinical diagnosis of intracranial hypotension and a control group was performed with measurements of the pontomesencephalic angle, mamillopontine distance, and lateral ventricular angle. Qualitative evaluation of other MRI findings included dural enhancement, venous engorgement, subdural collections, brainstem slumping, and tonsillar herniation. RESULTS In 29 patients with intracranial hypotension, the mean pontomesencephalic angle, mamillopontine distance, and lateral ventricular angle were 41.2° (SD, ± 17.4°), 4.4 mm (SD, ± 1.8), and 130.1° (SD, ± 9.8°), respectively. In the control group, the mean pontomesencephalic angle, mamillopontine distance, and lateral ventricular angle were 65° (SD, ± 9.9°), 7.0 mm (SD, ± 1.3), and 132.2° (SD, ± 5.7°), respectively. The differences in the pontomesencephalic angle and mamillopontine distance values for the intracranial hypotension group versus the control group were statistically significant (p < 0.01). The difference in the lateral ventricular angle measurements was not statistically significant (p = 0.37). Cutoff points of a 5.5-mm mamillopontine distance and 50° pontomesencephalic angle were estimated using receiver operating characteristic curves. CONCLUSION In patients with the clinical suspicion of intracranial hypotension, we found that cutoff values of 5.5 mm or less for the mamillopontine distance and 50° or less for the pontomesencephalic angle were sensitive and specific in strengthening the qualitative MRI findings. Therefore, quantitative assessments may provide a more accurate diagnosis.

Decompressive craniectomy or medical management for refractory intracranial hypertension: An AAST-MIT propensity score analysis

BACKGROUND Moderate/severe traumatic brain injury (TBI) management involves minimizing cerebral edema to maintain brain oxygen delivery. While medical therapy (MT) consisting of diuresis, hyperosmolar therapy, ventriculostomy, and barbiturate coma is the standard of care, decompressive craniectomy (DC) for refractory intracranial hypertension (ICH) has gained renewed interest. Since TBI treatment guidelines consider DC a second-tier intervention after MT failure, we sought to determine if early DC (<48 hours) was associated with improved survival in patients with refractory ICH. METHODS Eleven Level 1 trauma centers provided clinical data and head computed tomographic scans for patients with a Glasgow Coma Scale (GCS) score of 13 or less and radiographic evidence of TBI excluding deaths within 48 hours. Computed tomographic scans were graded according to the Marshall classification. A propensity score to receive DC (regardless of whether DC was performed) was calculated for each patient based on patient characteristics, physiology, injury severity, GCS, severity of intracranial injury, and treatment center. Patients who actually received a DC were matched to patients with similar propensity scores who received MT for analysis. Outcomes were compared between early (<48 hours of injury) primary or secondary DC and matched controls and then between early primary DC only and matched controls. RESULTS There were 2,602 patients who met the inclusion criteria ,of whom 264 (10.1%) received DC (either primary or secondary to another cranial procedure) and 109 (5%) had a DC that was primary. Variables associated with performing a DC included sex, race, intracranial pressure monitor placement, in-house trauma attending, traumatic subarachnoid hemorrhage, midline shift, and basal cistern compression. There was no survival benefit with early primary DC compared with the controls (relative risk, 1.07; 95% confidence interval, 0.67–1.73; p = 0.77), and resource use was higher. CONCLUSION Early DC does not seem to significantly improve mortality in patients with refractory ICH compared with MT. Neurosurgeons should pause before entertaining this resource-demanding form of therapy. LEVEL OF EVIDENCE Therapeutic care/management, level III.

Isolated intramedullary neurosarcoidosis of the thoracic spine: case report and review of the literature.

Sarcoidosis can involve the central nervous system in approximately 5–15% of cases. Any part of the nervous system can be involved, so presentation can be quite varied. Isolated disease of the spinal cord is even less common and reports are limited to single cases and small series. Although in the setting of systemic disease the diagnosis can be made with skin or lymph node biopsy, isolated disease of the spinal cord presents a diagnostic challenge. We present a case of isolated intramedullary neurosarcoidosis of the distal thoracic spinal cord presenting with posterior column dysfunction. Imaging demonstrated T2 changes in the patient’s lower thoracic cord adjacent to disc herniation. Over time, however, his symptoms progressed despite decompression, and the abnormal region began to exhibit focal contrast enhancement. The persistence of symptoms as well as the new enhancement led us to perform a spinal cord biopsy, which demonstrated histopathological findings consistent with sarcoidosis. Further workup failed to reveal any evidence of systemic disease. Intramedullary sarcoidosis without systemic sarcoidosis is extremely rare. With its variable imaging appearance and inconsistent clinical manifestations, it can be difficult to diagnose. It should be considered in the differential diagnosis of a mass-like intramedullary lesion with progressive symptoms. Biopsy with histopathological correlation may be the only definite management option.