Emergency Imaging of Brain Tumors: Complications & Summary

This video is the seventh and final video in an overview about the emergent approach to brain tumor imaging. This video talks about frequent complications you might see in the clinical care and imaging of brain tumor patients. The most important complications you need to be aware of are infarction, herniation, hemorrhage, tumor progression or radiation necrosis, and hydrocephalus.

Post-resection infarct

This patient’s preoperative imaging shows a tumor in the left temporal lobe that you can see on CT and MRI. On post-op imaging, the tumor has been resected, but there is a wedge-shaped periphery of abnormal diffusion posterior to the cavity. Sometimes patients can have a thin rim of DWI abnormality after a resection, but this more than expected. This is a post-operative infarct. Remember, on delayed imaging this can have enhancement, but it will usually have a gyriform pattern which is different from the original tumor.

Tumor progression

This is a patient who is 2 weeks into radiation therapy for a tumor in the right posterior temporal lobe and inferior parietal lobe. Within this time, there is a lot more edema in the tumor bed with small areas of hemorrhage. The differential diagnosis here is acute radiation necrosis or rapidly worsening tumor.  The MRI confirms that there is marked worsening of enhancement, mass effect, and tumor. This was diagnosed as rapid worsening of tumor and the patient was ultimately transferred for palliative care. Remember though that acute radiation necrosis and worsening tumor can have the same appearance.

Post-operative infection and hydrocephalus

This patient had a recent resection of a tumor with implantation of brachytherapy implants. The post-op pneumocephalus has improved, but ge has developed new postdural collections and new hydrocephalus. This was concerning for acute infection, and the patient was also febrile. This patient had an additional surgery to evacuate the fluid collections, wash out the wound, and place a ventricular drain.

Recap of complications

In summary, you can see a number of complications in patients with brain tumors, many of which will be visible on CT. When you have a suspicion for these things, you should communicate with the surgeons and neuro-oncologists as it can precipitate a change in management.

Lecture series summary

In this lecture, we’ve talked about the role of imaging in brain tumor patients, particularly in the emergent settings, including a review of the role of imaging, some common tumors, and common complications to be on the lookout for.

Thanks for tuning in. Be sure to check out the other videos on the brain tumor topic page if you want to learn more about brain tumors. Also check out the Emergency Imaging of Brain Tumors Playlist to see all the videos from this lecture.

Emergency Imaging of Brain Tumors: Tumor mimics

This video is the sixth video in an overview about the emergent approach to brain tumor imaging. This video talks about some of the common mimics for things that look like tumors. The most common diagnoses you need to be aware of are infection, abscess, and demyelination.

Herpes encephalitis

This case shows a CT in a patient that has hypodensity in the left medial temporal lobe. It is ill-defined and not well marginated. On CT, the differential is an acute encephalitis and tumor. Stroke is less likely given that it isn’t in a vascular distribution and doesn’t have the right clinical onset. The MRI shows really apparent swelling and edema/hyperintensity on T2 and FLAIR. Diffusion is also hyperintense. On post-contrast imaging, there is avid and solid nodular and ill-defined enhancement.

Herpes encephalitis is a dreaded intracranial infection that requires urgent recognition and treatment. It can be unilateral or bilateral, and is often asymmetric. Red flags include temporal involvement, acute clinical signs of illness, and not following a vascular distribution. These patients may have rapid progression. If no cause is found via clinical workup or lumbar puncture, these patients should get a follow-up in 6-12 weeks to ensure that it is improve and is not a tumor.

Abscess

This case has a CT which shows marked edema in the left frontal lobe with a mass in the left frontal lobe adjacent to the frontal horn. It looks like the mass is peripherally hyperdense but hypodense centrally. It is not following a vascular distribution. Your differential diagnosis includes tumors, both primary tumors and metastatic disease. An MRI and systemic work-up for malignancy are justified. The MRI shows a mass with peripheral T2 hyperintensity and small areas of susceptibility which are probably blood products. On post-contrast imaging, the periphery is avidly enhancing with blurry margins. The DWI images are key and show pretty marked central diffusion hyperintensity which is dark on ADC.

This is a case of intracranial abscess. Brain abscesses are areas of pus and infection within the brain which have central diffusion restriction. Sometimes there are thinner along the ventricular margin. In many ways they can mimic tumors, but the central DWI hyperintensity which is “light-bulb” bright is a huge clue that you should suspect abscess. Red flags that should make you suspect infection are immune compromised patient, systemic signs of infection, rapid onset, and severe symptoms.

Tumefactive demyelination

This patient has a CT which looks somewhat similar to the previous patient. There is a marked area of edema with sparing of the cortex in the left parietal lobe. There is no clear central mass that you see there, but given that it is vasogenic edema and there is mass effect you should be pretty suspicious. Your initial differential includes primary tumor and metastatic disease, but you want to see the MRI. The MRI shows a marked area of FLAIR and T2 hyperintensity. The area is markedly T1 hypointense but has heterogeneous and incomplete enhancement around the rim.

Tumefactive demyelination is associated with patients who have other demyelinating disease. In many cases, it’s going to be indistinguishable from tumor, but clues are sudden onset of symptoms and young age of the patient. Imaging features to look for are that incomplete rim of enhancement around the margin and the leading edge of abnormal diffusion.

Summary

When approaching a case that seems like a tumor, you have to remember that there are lesions that can mimic tumors. Systemic signs or clinical features can help you, but it can be particularly hard on CT alone. The next step is to get an MRI and work the patients up for their systemic features.

Thanks for tuning in. Be sure to check out the other videos on the brain tumor topic page if you want to learn more about brain tumors. Also check out the Emergency Imaging of Brain Tumors Playlist to see all the videos from this lecture.