Unruptured giant lateral thoracic meningocele: extremely rare cause of cerebrospinal fluid (CSF) hypotension in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is a multisystem neurocutaneous disorder. Scoliosis and dural ectasia are features of the associated mesodermal dysplasia. Lateral thoracic meningoceles can develop in NF1 and progressively enlarge due to cerebrospinal fluid (CSF) pulsations. Large meningoceles can cause compressive symptoms in the thorax. We are reporting a case of a NF1 presenting with acute onset respiratory distress, who also had chronic orthostatic headaches. CT chest showed unruptured enlarging bilateral lateral thoracic meningoceles causing lung compression. MRI of the brain and spine showed features of CSF hypotension, explaining the headaches. CSF hypotension with unruptured meningoceles is extremely rare. Management of the condition is challenging since surgical removal is prone to complications due to underlying mesodermal abnormalities. Cystoperitoneal shunting to relieve lung compression may worsen CSF hypotension. A shunt with a programmable valve allowed controlled drainage and successfully relieved lung compression without worsening of orthostatic headaches in our case.

Case 302.

History A 21-year-old immunocompetent man who was a long-term resident of Qatar presented to the emergency department with recurrent episodes of unprovoked generalized tonic-clonic seizures lasting 2-3 minutes that spontaneously resolved and were associated with postictal confusion. The patient also had progressive mild diplopia, intermittent dizziness, and numbness in the left arm over the course of 3 months. The patient did not have any other systemic symptoms or chronic medical diseases. He did not have any history of intake of illicit drugs, supplements, or regular medications; he had not received any recent vaccinations; and he had not undergone any surgical procedures. He had no history of travel. At presentation, vital signs were normal. Neurologic examination showed mild left homonymous hemianopia, normal gait with no cerebellar signs, and preserved sensations, power, tone, and reflexes in all four limbs. An electroencephalogram showed no epileptiform discharges. Chest CT and extensive laboratory work-up, including viral, fungal, bacterial, and parasite work-up, thyroid function tests, and immunologic blood tests yielded normal results. Those included normal complete and differential blood counts and normal serum chemistry. Serum analysis was negative for antinuclear antibody, Sjögren syndrome antigens A and B, cytoplasmic antineutrophil cvtoplasmic antibody, and paraneoplastic profile. Serum evaluation was also negative for human immunodeficiency virus type 1 and type 2 RNA, and Brucella, Schistosoma, and toxoplasma antibodies. Venereal Disease Research Laboratory (VDRL) and rapid plasma regain (RPR) test results were negative. Cerebrospinal fluid (CSF) analysis revealed clear fluid and normal pressure and biochemistry, except for elevated protein concentration (0.48 g/L) (normal range, 0.15-0.45 g/L). There were 43 leukocytes/µL (99% lymphocytes) (normal range, 0-5 leukocytes/µL; lymphocytes range, 40%-80%), with no atypical or malignant cells. CSF Gram staining, acid-fast staining, cryptococcal antigen, varicella-zoster virus polymerase chain reaction (PCR), herpes simplex virus PCR, VDRL, and RPR test results were negative. CSF cultures did not show any evidence of growth of bacteria, fungi, or acid-fast bacillus. CSF flow cytometry did not show a monoclonal lymphoid population. No CSF oligoclonal bands were detected. Conventional brain MRI with intravenous administration of contrast material and a perfusion study were performed and included different sequences (Figs 1-3).

Case 302: Supratentorial Lymphocytic Inflammation with Parenchymal Perivascular Enhancement Responsive to Steroids.

HISTORY: Part one of this case appeared 4 months previously and may contain larger images. A 21-year-old immunocompetent man who was a long-term resident of Qatar presented to the emergency department with recurrent episodes of unprovoked generalized tonic-clonic seizures lasting 2-3 minutes that spontaneously resolved and were associated with postictal confusion. The patient also had progressive mild diplopia, intermittent dizziness, and numbness in the left arm over the course of 3 months. The patient did not have any other systemic symptoms or chronic medical diseases. He did not have any history of intake of illicit drugs, supplements, or regular medications; he had not received any recent vaccinations; and he had not undergone any surgical procedures. He had no history of travel. At presentation, vital signs were normal. Neurologic examination showed mild left homonymous hemianopia, normal gait with no cerebellar signs, and preserved sensations, power, tone, and reflexes in all four limbs. An electroencephalogram showed no epileptiform discharges. Chest CT and extensive laboratory work-up, including viral, fungal, bacterial, and parasite work-up, thyroid function tests, and immunologic blood tests yielded normal results. Those included normal complete and differential blood counts and normal serum chemistry. Serum analysis was negative for antinuclear antibody, Sjögren syndrome antigens A and B, cytoplasmic antineutrophil cvtoplasmic antibody, and paraneoplastic profile. Serum evaluation was also negative for human immunodeficiency virus type 1 and type 2 RNA, and Brucella, Schistosoma, and toxoplasma antibodies. Venereal Disease Research Laboratory (VDRL) and rapid plasma regain (RPR) test results were negative. Cerebrospinal fluid (CSF) analysis revealed clear fluid and normal pressure and biochemistry, except for elevated protein concentration (0.48 g/L) (normal range, 0.15-0.45 g/L). There were 43 leukocytes/µL (99% lymphocytes) (normal range, 0-5 leukocytes/µL; lymphocytes range, 40%-80%), with no atypical or malignant cells. CSF Gram staining, acid-fast staining, cryptococcal antigen, varicella-zoster virus polymerase chain reaction (PCR), herpes simplex virus PCR, VDRL, and RPR test results were negative. CSF cultures did not show any evidence of growth of bacteria, fungi, or acid-fast bacillus. CSF flow cytometry did not show a monoclonal lymphoid population. No CSF oligoclonal bands were detected. Conventional brain MRI with intravenous administration of contrast material and perfusion study were performed and included different sequences (Figs 1-3).

Autoimmune encephalitis and seizures, cerebrospinal fluid, imaging, and EEG findings: a case series.

Antibody-mediated encephalitides constitute a group of inflammatory brain diseases characterized by prominent neuropsychiatric symptoms and are associated with antibodies against neuronal cell-surface proteins, ion channels, or receptors. The diagnosis and management of autoimmune encephalitis include evaluation of the clinical presentation, brain imaging, cerebrospinal fluid (CSF) findings, antibody detection, and electroencephalography (EEG) findings. This is a retrospective study of adults 18 years or older with autoimmune encephalitis due to antibodies against membrane surface antigens as well as anti-glutamic acid decarboxylase (anti-GAD) antibodies. The electronic medical record was reviewed for demographic data, clinical data, laboratory results, EEG, and imaging findings. Antibody screening was requested for 341 patients between May 2014 and December 2019. Antibody screening was positive in 37 patients presenting with seizures and/or encephalopathy. Of these, 10 patients tested positive for antibodies against neuronal surface antigens or anti-GAD antibodies-2 patients had anti-GAD antibody encephalitis, 5 had anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, and 3 had anti-leucine-rich glioma-inactivated 1 (anti-LGI1) encephalitis. Demographics, clinical presentation, EEG, imaging, and CSF findings are reported. Autoimmune encephalitides are a diverse group of disorders with a few common clinical features and MRI findings. MRI, EEG, and CSF findings can be normal or show nonspecific findings in autoimmune encephalitis. Therefore, early diagnosis of these disorders requires a high level of suspicion to avoid delaying the diagnosis. Carefully looking for diagnostic clinical features (e.g., faciobrachial dystonic seizures in anti-LGI1 encephalitis), significant findings in MRI (e.g., limbic encephalitis), and some EEG patterns (e.g., extreme delta brush and generalized rhythmic delta activity in anti-NMDAR encephalitis) may help in early diagnosis.

Embolic Pattern of Stroke Associated with Cardiac Wall Motion Abnormalities; Narrowing the Embolic Stroke of Undetermined Source Category.

BACKGROUND: There is ambiguity regarding the role of left ventricle wall motion abnormalities (LVWMAs) as a potential cardioembolic source in patients, who satisfy embolic stroke of undetermined source (ESUS) criteria. METHODS AND RESULTS: We analyzed prospectively collected data in 345 acute stroke patients, 185 (53.6%) stroke with atrial fibrillation (SwAF), and 160 (46.4%) stroke with LVWMA. LVWMA were younger (P = .003), had significantly higher frequency of stroke risk factors and lower ejection fraction (P < .001). No significant difference was found between the stroke pattern in SwAF and LVWMA except focal cortical, cortical-subcortical lesions were more frequent in LVWMA (P = .002). Mean wall motion score index (WMSI) was 1.523 (range 1.05-2.71) without any correlation between the severity of WMSI and multiple strokes (P = .976). In subgroup analyses vertical basal WMSI (P = .030) and vertical mid cavity WMSI (P = .010) was significantly related to branch arterial stroke. LVWMA 94 (65%) patients were on antiplatelet/anticoagulation compared to 47 (52.4%) with atrial fibrillation (AF), with no significant difference in stroke recurrence during 4 years follow-up (P = .15). CONCLUSIONS: Patients with LVWMA who satisfy ESUS criteria, have stroke pattern on diffusion-weighted magnetic resonance imaging and risk of stroke recurrence similar to AF-related stroke despite being on appropriate antiplatelet medications. Further studies with anticoagulation therapy may be required in this group of patients to improve the high risk of recurrent stroke.

A practical review of the muscles of facial mimicry with special emphasis on the superficial musculoaponeurotic system.

OBJECTIVE: In this article, we elaborate a practical approach to superficial facial anatomy enabling easy identification of the facial mimic muscles by classifying them according to their shared common insertion sites. CONCLUSION: The facial mimic muscles are often difficult to identify on imaging. By tracing them from their common group insertion sites back to their individual origins as well as understanding key anatomic relationships, radiologists can more accurately identify these muscles.

Functional Magnetic Resonance Imaging (MRI) and MRI Tractography in Progressive Supranuclear Palsy-Like Syndrome.

An 18-year-old woman underwent an uneventful ascending aortic aneurysm repair then developed progressive supranuclear palsy-like syndrome. Extensive neuroimaging including contrasted fat-suppressed cranial and orbital magnetic resonance imaging (MRI), MRI tractography, and functional MRI (fMRI) revealed no clear radiographic involvement except for a single tiny hypoechoic midbrain dot on the T2*-weighted gradient-echo imaging, which is not considered sufficient to account for the patient's deficits. This case attests to the occult nature of this rare and devastating syndrome.

Reversible blindness in cryptococcal meningitis with normal intracranial pressure: case report and review of the literature.

Ocular complications in cryptococcal meningitis (CM) are commonly attributed to elevated intracranial pressure (ICP). We report a case of reversible vision loss complicating AIDS-related CM with a normal ICP. We review other cases of blindness in CM with normal ICP and the potential role of corticosteroids as treatment.

CT perfusion in stroke: Comparing conventional and RAPID automated software.

CT perfusion (CTP) imaging is increasingly used for routine evaluation of acute ischemic stroke. Knowledge about the different types of CTP software, imaging acquisition and post-processing, and interpretation is crucial for appropriate patient selection for reperfusion therapy. Conventional vendor-provided CTP software differentiates between ischemic penumbra and core infarct using the tiebreaker of critically reduced cerebral blood volume (CBV) values within brain regions showing abnormally elevated time parameters like mean transit time (MTT) or time to peak (TTP). On the other hand, RAPID automated software differentiates between ischemic penumbra and core infarct using the tiebreaker of critically reduced cerebral blood flow (CBF) values within brain regions showing abnormally elevated time to maximum (Tmax). Additionally, RAPID calculates certain indices that confer prognostic value, such as the hypoperfusion and CBV index. In this review, we aim to familiarize the reader with the technical principles of CTP imaging, compare CTP maps generated by conventional and RAPID software, and discuss important thresholds for reperfusion and prognostic indices. Lastly, we discuss common pitfalls to help with the accurate interpretation of CTP imaging.

Revisiting the "Puffed Cheek" Technique: Advantages, Fallacies, and Potential Solutions.

The "puffed cheek" technique is routinely performed during CT neck studies in patients with suspected oral cavity cancers. The insufflation of air within the oral vestibule helps in the detection of small buccal mucosal lesions, with better delineation of lesion origin, depth, and extent of spread. The pitfalls associated with this technique are often underrecognized and poorly understood. They can mimic actual lesions, forfeiting the technique's primary purpose. This review provides an overview of the puffed cheek technique and its associated pitfalls. These pitfalls include pneumoparotid, soft palate elevation that resembles a nasopharyngeal mass, various tongue displacements or distortions that obscure tongue lesions or mimic them, sublingual gland herniation, an apparent exacerbation of the airway edema, vocal cord adduction that hinders glottic evaluation, and false indications of osteochondronecrosis in laryngeal cartilage. Most stem from a common underlying mechanism of unintentional Valsalva maneuver engaged in by the patient while trying to perform a puffed cheek, creating a closed air column under positive pressure with resultant surrounding soft-tissue displacement. These pitfalls can thus be avoided by instructing the patient to maintain continuous nasal breathing while puffing out their cheek during image acquisition, preventing the formation of the closed air column. Keywords: CT, Head/Neck © RSNA, 2024.

Ectopic cervical thymus: Recognising the characteristic 'embroidery yarn' appearance on ultrasound.

Introduction: The thymus normally forms in the neck from the third pharyngeal pouch and descends to its normal position in the mediastinum. Arrest of descent or sequestration of thymic tissue can occur at any point along its path leading to an ectopic thymus which can present as a neck mass, usually in the paediatric age group. Purpose and Case Report: Ultrasound is generally performed in the presence of a neck mass in children. Although a characteristic 'starry sky' appearance of the thymus has been described on ultrasound, it is not considered sufficiently specific and cross-sectional imaging with magnetic resonance imaging is usually performed. On magnetic resonance imaging, the ectopic thymus appears as a homogeneous T1 isointense and T2 hyperintense mass and may actually appear ominous due to the tendency of ectopic thymus to sometimes show diffusion restriction unlike the normal thymus. Subsequent invasive biopsy or surgical removal is usually necessary to rule out a neoplastic lesion. In our observation, the ultrasound appearance of thymus is sufficiently distinctive to be confidently diagnosed as ectopic thymic tissue. This appearance is similar to the high-resolution appearance of an embroidery yarn. The reason most radiologists are not aware of the same is because the normal mediastinal thymus is not usually imaged by ultrasound. Conclusion: An accurate diagnosis on ultrasound would mean avoidance of expensive cross-sectional imaging and invasive biopsy or surgical excision in favour of regular non-invasive follow-up ultrasound scans until the lesion involutes in late childhood.

Lumbar vertebral diskitis-osteomyelitis with mycotic abdominal aortic aneurysm caused by Streptococcus mitis.

Vertebral osteomyelitis is a well-documented disease entity in literature with various known etiologies. However, vertebral diskitis-osteomyelitis secondary to an infected aortic aneurysm is an uncommon and life-threatening complication. We present the case of a 65-year-old male patient who presented with chronic low back pain that acutely worsened for 1 to 1.5 months and was diagnosed with vertebral diskitis-osteomyelitis secondary to a contiguous infection from an adjacent mycotic aortic aneurysm. To our knowledge, this is one of the few cases reported of vertebral diskitis-osteomyelitis secondary to mycotic aortic aneurysm. We discuss the findings on CT and MRI, as well as the value of imaging in guiding management.

Esophageal entrapment with blunt thoracic spinal trauma.

Esophageal injury due to blunt trauma rarely occurs. However, prompt diagnosis and treatment of such injury is essential to improve patient survival. We report an extremely rare case of esophageal entrapment within a hyperextension fracture dislocation of the thoracic spine, which was diagnosed by reviewing an esophagram and CT image simultaneously. Esophageal injury should be considered with thoracic spine trauma, especially if the T3/4 level is involved.

Susac syndrome. A differential diagnosis for demyelination.

Susac syndrome is a microangiopathy of unknown origin, probably autoimmune, affecting capillaries and precapillary arterioles of the brain, retina, and inner ear. It is often misdiagnosed as acute disseminated encephalomyelitis or multiple sclerosis. We report the case of a 25-year-old male with Susac syndrome who developed the clinical triad of encephalopathy, visual and hearing problems over the course of a year. The characteristic MRI findings including central corpus callosal involvement and brain infarctions were supported by branch retinal arterial/arteriolar occlusions on fluorescein retinal angiography. Most patients with Susac syndrome will not have the complete clinical triad initially. A very high index of suspicion is required by the clinician and radiologist in patients with any component of the clinical triad so as not to misdiagnose the MRI findings for demyelination. Even if initial ophthalmologic examinations are normal, these patients should be followed up for later development of branch retinal artery occlusions.

Rathke cleft cyst. MRI criteria for presumptive diagnosis.

OBJECTIVE: To define MRI criteria for the presumptive diagnosis of Rathke cleft cyst (RCC). METHODS: One hundred and three patient MRI scans suggesting RCC performed between January 2005 and January 2011 were retrospectively reviewed for indications, cyst location, T1 and T2 signal intensity, dimensions, encroachment on optic chiasm, enhancement pattern, and stability over a year. RESULTS: Of the 103 patients analyzed, the suggestion of RCC was an incidental finding in 82.5% (n=85) of patients. Headache was the most common symptom in 11.6% (n=12), visual field deficit in 3.8% (n=4), and both headache and visual field deficit in 0.97% (n=1). The cyst was hyperintense on T1 in 55.3% (n=57), hypointense in 27.1% (n=28), and isointense in 17.4% (n=18). The cyst was T2 hyperintense in 57.2% (n=59), and iso-hypointense in 42.7% (n=54). The cyst showed no enhancement in 80.5% (n=83), and a thin marginal enhancement in 19.4% (n=20). The cyst showed a stable appearance in 99% (n=102) of patients after at least one year follow-up MRI study. CONCLUSION: Rathke cleft cysts typically have a cystic appearance with T1 hyperintensity, sometimes with T1 iso- or hypointensity, variable T2 signal, and no or thin marginal enhancement and remain stable in size over time.

Practical microscopic neuroanatomy of the limbic system and basal forebrain identifiable on clinical 3T MRI.

Microscopic neuroanatomy of limbic system and basal forebrain on MRI is complex and is a terra incognita for many radiologists, clinicians, and neuroscientists. Interestingly, most of the important structures/at least anatomical regions containing these structures demonstrable on cadaveric and surgical dissections can be identified on clinical MRI, with 3T being much better than 1.5T. This article teaches the practical MRI identification of these structures which will greatly help in evaluating complex ailments like temporal lobe epilepsy, Alzheimer dementia, and other neuropsychiatric disorders. This knowledge will also aid in accurate reporting of tumor spread along the white matter fasciculi in the temporal stem/basal forebrain region. Limbic system includes the mesial temporal structures and their connections, piriform cortex including "area tempestas," and the septal area comprising of subcallosal area and paraterminal gyrus. Basal forebrain includes structures like substantia innominata with basal nucleus of Meynert, diagonal gyrus/diagonal band of Broca, and nucleus accumbens lying in between the anterior perforated substance inferiorly and the anterior commissure superiorly.

Injury to the circuit of Papez: An overlooked cause of recurrent seizures.

Key Clinical Message: Papez' circuit is a unique neural pathway in the limbic system that is correlated with seizure activity. Injuries affecting Papez' circuit are often small and unusual in location but can be identifiable in MRI and functional imaging modalities, which can be helpful in the workup of refractory epilepsy. Abstract: The Papez circuit is a unique neural pathway in the limbic system of the brain. We review a patient presenting with recurrent seizures as the main manifestation of Papez' circuit pathology. The radiologic features of ischemia involving the mammillothalamic tract in Papez' circuit were correlated with the seizure activity.

MR imaging differentiating features between lytic and degenerative lumbosacral spondylolisthesis.

Spondylolisthesis is characterized by the displacement of one vertebral body in relation to the adjacent vertebra. It is commonly observed in the lower lumbar region and can be caused by a variety of factors, including spondylolysis (a fracture in the pars interarticularis) or degenerative disease. Magnetic resonance imaging (MRI) is becoming increasingly popular as the primary modality for evaluation of low back pain and is often used in the absence of radiographs or Computed Tomography. However, it can be challenging for radiologists to differentiate between the two types of spondylolisthesis based on MRI alone. The goal of this article is to identify key imaging features on MRI that can aid radiologists in differentiating between spondylolysis and degenerative spondylolisthesis on MRI. Five key concepts are discussed: the "step-off" sign, the "wide canal" sign, T2 cortical bone signal on MRI, epidural fat interposition, and fluid in the facet joints. The utility, limitations and potential pitfalls of these concepts are also discussed to provide a comprehensive understanding of their use in differentiating between the two types of spondylolisthesis on MRI.

Recurrent sporadic malignant triton tumor in the carotid sheath in the absence of neurofibromatosis.

Malignant Triton Tumors (MTTs) are a rare and aggressive subtype of malignant peripheral nerve sheath tumors (MPNSTs), often associated with neurofibromatosis type 1. This case report describes a unique instance of recurrent sporadic MTT within the carotid sheath in a 33-year-old male without any personal or familial history of neurofibromatosis. The patient initially presented with a biopsy-confirmed MTT in the right neck, involving the carotid body and brachial plexus, and underwent partial resection, radiation therapy, and chemotherapy. Six months later, the patient presented with recurrent MTT, and subsequently underwent radical tumor resection, segmental right carotid artery resection, and deep femoral vein interposition. Recovery was complicated by hematoma formation, and the patient developed vocal fold paralysis and a left vocal fold cyst, necessitating further surgeries. Yearly follow-ups for 8 years revealed no recurrence. This case emphasizes the importance of comprehensive patient evaluation, including clinical history, imaging, and biopsy findings, for accurate diagnosis and prompt surgical intervention in managing such rare and aggressive tumors. Further research is needed to identify novel therapies and improve survival rates for patients with MTTs.

Synchronous Ectopic Thyroid Gland and Ectopic Parathyroid Adenoma on 99mTc-Sestamibi Scintigraphy and Correlative Imaging.

99mTc-sestamibi scintigraphy localizes parathyroid adenoma as a persistent focus of uptake on delayed images, whereas thyroid glands in normal or ectopic locations are seen on only early images and wash out on delayed images. We report a case of absence of eutopic neck thyroid activity and synchronous ectopic lingual thyroid and mediastinal parathyroid adenoma on scintigraphy confirmed with CT.