1. The Corpus Callosum: Imaging the Middle of the Road
Elizabeth Roy, MD, Cameron Hague, MD, Bruce Forster, MD, Rob Colistro, MD, Gordon Andrews, MD 
Canadian Association of Radiologists Journal 
Volume 65, Issue 2, Pages (May 2014)
DOI: /j.carj
Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

2. Figure 1
(A) Dysgenesis of the corpus callosum. Coronal post gadolinium T1 (repetition time [TR] 2300, echo time [TE] 19); (B) fluid-attenuated inversion recovery (TR 9850, TE 97) magnetic resonance images of a 18-year-old man, revealing typical findings of dysgenesis and/or the absence of the corpus callosum (short arrow), with colpocephaly (long arrow), high riding third ventricle, and eversion of the cingulate gyrus.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

3. Figure 2
Pericallosal lipoma. Noncontrast computed tomography of a 45-year-old female patient with a history of headaches, demonstrating a lobulated oblong fat density lesion (−68 HU) in a pericallosal location. No dysgenesis of the corpus callosum was present in this case, and the lipoma was considered an incidental finding.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

4. Figure 3
Glioblastoma multiforme (GBM). (A) Axial fluid-attenuated inversion recovery image (repetition time [TR] 9850, echo time [TE] 97) and (B) sagittal noncontrast T1 image (TR 2300, TE 19) in a 76-year-old man with increasing confusion, demonstrating a heterogeneous mass expanding the splenium of the corpus callosum (arrow) with associated oedema in the occipital white matter. (C) An axial noncontrast computed tomographic image in a different patient, revealing a predominantly low-density mass situated likewise in the splenium of the corpus callosum (arrow). Interestingly, both of the masses were identified within weeks of each other, and both were proven to represent GBM on pathology.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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5. Figure 4
Primary central nervous system lymphoma. A noncontrast computed tomographic image in a 34-year-old patient with human immunodeficiency virus, demonstrating multifocal high-density lesions, which involve both the splenium (long arrow) and genu (short arrow) of the corpus callosum.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

6. Figure 5
Secondary central nervous system lymphoma of a 65-year-old patient shown in a contrast-enhanced computed tomographic image. The large enhancing mass involves the genu of the corpus callosum, demonstrating surrounding low-density oedema. The patient presented with history of intra-abdominal B-cell lymphoma, recent onset headache, and incontinence, as well as memory impairment.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
Copyright © 2014 Canadian Association of Radiologists Terms and Conditions

7. Figure 6
Diffuse axonal injury. (A) Coronal images of a magnetic resonance gradient sequence (repetition time 500, echo time 13) through the splenium, and (B) body of the corpus callosum in a 43-year-old female patient with chronic headache and various neurologic symptoms, revealing a region of low signal with susceptibility artifact (arrows) consistent with hemosiderin deposition. This patient had a history of a high-speed motor vehicle collision 1 year before this study.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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8. Figure 7
Radiation injury. (A) T2 fluid-attenuated inversion recovery (FLAIR) (repetition time [TR] 9850, echo time [TE] 97) and (B) 3-dimensional fast imaging employing steady-state acquisition (FIESTA) (TR 4.9, TE 1.5) magnetic resonance sequences in a 27-year-old female patient with a history of external-beam radiation and prior resection of a right-sided posterior fossa medulloblastoma 13 years earlier. (A) The FLAIR image reveals a high signal in the right posterior white matter (short arrow) and splenium (long arrow). (B) The 3-dimensional FIESTA image, demonstrating the surgical changes posterior to the right cerebellopontine angle (arrow).
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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9. Figure 8
Multiple sclerosis (MS). (A) Coronal and (B) axial postgadolinium T1 magnetic resonance images (repetition time 2300, echo time 19) in a 42-year-old female patient with known MS and a worsening clinical course, demonstrating dense band-like enhancement across the body of the corpus callosum (short arrows) and a partially rim-enhancing lesion within the right corona radiata (long arrows). Enhancement of lesions in patients with known MS usually correlates with activity.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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10. Figure 9
Ischemic infarction. (A) Contrast-enhanced computed tomography (CT), (B) diffusion-weighted imaging (DWI), and (C) apparent diffusion coefficient (ADC) map magnetic resonance imaging (MRI) (repetition time 6200, echo time 79) in a 55-year-old male patient with sudden onset of neurologic symptoms. Initial CT (not shown) revealed a subtle region of low density in the genu. (A) A contrast-enhanced CT performed 12 hours later, demonstrating evolution of the low-density change in the genu, with a lack of enhancement (arrow). (B, C) Subsequently performed MRIs, revealing true restricted diffusion, with high signal on DWI images and corresponding low signal on the ADC map. Given the clinical and radiologic course, the findings were in keeping with infarction.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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11. Figure 10
Cerebral fat embolism. (A) fluid-attenuated inversion recovery (FLAIR) (repetition time [TR] 9850, echo time [TE] 97), (B) diffusion-weighted imaging, and (C) apparent diffusion coefficient map images (TR 6200, TE 79) of a 24-year-old female cyclist who presented with a broken femur and after surgery developed a decreased level of consciousness. An MRI was performed, demonstrating multiple foci of high T2/FLAIR signal in the corona radiata (not shown) and splenium of the corpus callosum, which demonstrated restricted diffusion (arrows on all sequences). This pattern of infarction is consistent with cerebral fat embolization.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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12. Figure 11
Acute disseminated encephalomyelitis: fluid-attenuated inversion recovery axial magnetic resonance image (repetition time 9850, echo time 97) in a 23-year-old male patient with acute-subacute onset of neurologic symptoms, demonstrating high T2 signal intensity within the posterior white matter and the corpus callosum. A further history identified that the patient had a respiratory viral infection 2 weeks earlier. Follow-up studies revealed complete resolution of T2 signal changes and symptoms at 4 months of follow-up (not shown).
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
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13. Figure 12
Progressive multifocal leukoencephalopathy. (A) Noncontrast and (B) contrast-enhanced axial computed tomographic images of a 26-year-old male patient with human immunodeficiency virus and with a history of decreased level of consciousness reveal multifocal, bilateral white matter low-density areas (short arrows), also involving the splenium of the corpus callosum (long arrow). No significant mass effect or enhancement is present. A history revealed that the patient had discontinued antiretroviral therapy 3 months earlier.
Canadian Association of Radiologists Journal  , DOI: ( /j.carj )
Copyright © 2014 Canadian Association of Radiologists Terms and Conditions