Sunday, September 26, 2010

Acoustic Neuroma

Acoustic neuromas are tumors found in the inner ear.  Patients with these tumors will present with ringing in ears, usually unilateral sensory neural hearing loss (SNHL), fullness in the ear, roaring sounds, dizziness or vertigo and sometimes ear aches.  These symptoms are not all inclusive, but the majority of patients will have some or all of these symptoms. 

These tumors are not malignant, but they do require surgery for removal.  The surgical procedures will almost certainly leave the patient will hearing loss in that ear. 

I work on a GE scanner that uses a 3D FIESTA sequence, (3D Fast imaging with steady state), non contrast to better visualize the IAC's.  An acoustic neuroma will show up "dark" on the images.  The 3D FIESTA is also used to visualize other cranial nerves well, not just the VII and VIII.  The following website has done a study of the 3D FIESTA images vs. the FSE  T2 .  http://www.dirjournal.org/pdf/pdf_DIR_115.pdf

I have provided some images showing an acoustic neuroma almost entirely intracanalicular in the patients right IAC.
MRI T2 Axial IAC's
MRI 3D FIESTA Axial

MRI Coronal T1 Pre contrast

MRI T1 Axial pre contrast

MRI T1 Axial post contrast

MRI T1 Coronal post contrast



Sunday, September 19, 2010

MRI brain pathology - leptomeningeal carcinomatosis

I have seen this diagnosis a lot lately.  Patients will present VERY sick. These patients present with differing degrees of incapacity.  Some patients have known cancer and others have no known primary.  Mental status changes, inability to walk or perform everyday tasks.  Some patients can still communicate but limited and some present completely incapacitated.  Some cases that have no known primary, the physician may initially think the patient has a metabolic imbalance.Breast, lung and lymphoma are some of the most common cancers that will progress to this state.

Leptomeningeal carcinomatosis will show a large amount of meningeal enhancement with metastatic enhancement to the white matter of the brain also in some cases.  These patients outcomes are usually very grim.  This diagnosis is usually made towards the end of their life.  It is very sad when these images come across your monitor.

The following is a useful link I found which thoroughly describes the enhancement within the different layers of the brain:  http://emedicine.medscape.com/article/1156338-overview


Patient #1.  T1 Sagital pre contrast


Patient #1.  T1 Sagital post contrast.  See the leptomeningeal enhancement.


Patient #2.  T2 Axial.  Note the area of the thalamus and surrounding areas.  Not much to notice on the T2 image, but slight hyperintensity in this area compared to normal.


Patient #2.  T1 Axial pre contrast.

Patient #2.  T1 Axial post contrast.  See the white matter enhancement.