Sunday, December 12, 2010

MRI Lumbar Spine Disc Herniation

One of the most often scanned areas of the body is the lumbar spine.  An MRI of the lumbar spine is most often done to determine if a patient has a herniated disc.  Patients will usually present with low back pain with associated buttock or lower extremity pain.  Don't be alarmed if a patient has a lumbar disc but no apparent low back pain though.  Many patients do not complain of low back pain.  It just depends on which nerves are being compressed.  Routine MRI sequences are T1 and T2 sagitals and T1 and T2 axials.  STIR sagitals will be performed if the patient has had a distinct recent injury.  Here is a website with images and discussion about this:  http://www.mayfieldclinic.com/PE-HLDisc.htm

MRI Thoracic Spine

MRI of the thoracic spine is very useful to depict compression fractures.  These fractures can and do happen to individuals more often when they have low calcium levels in their bones.  Many times this will be the first sign that a person needs to be tested for osteoporosis.  Sometimes these fractures can be treated by a procedure called vertebroplasties.  This is were a substance like cement is injected into the vertebral body to help maintain the structure.    MRI is usually done to find these fractures.  You must do a STIR sequence with a routine study.  This will show if the fracture is acute.  A good website with further explanations and images about this is:  http://www.aafp.org/afp/2004/0101/p111.html

Sunday, November 14, 2010

MRI Cervical Spine Metastatic Disease

Many cancers will become metastatic and bones are a common place for the cancer to metastasize to.  Not all cancers due this, but many including lung and breast will find their way to the bone.  The most common sites for metastasis is the pelvis or spine.  When a cancer goes to the spine there is a possibility that it can cause a cord compression which is considered an emergency.  MRI's allow quick diagnosis of this.  There are not many emergency MRI's, but cord compressions top the list.  If a patient has a cord compression it can completely block the nerves and cause a patient to loss control of their body in many ways including bowel and bladder incontinence, inability to walk and loss of use of extremities.  These patients will usually present with uncontrolled or intractable pain in the spine.  http://www.merck.com/mmhe/sec06/ch093/ch093c.html is an educational website on cord compressions of all different types.  Usual imaging of cord compression with MRI include T1, T2 fatsats and sometimes STIR sagitals and T1 and T2 fatsat axials.  Post contrast imaging is also usually performed with repeating the T1 images.  The following are images of a slight cord compression laterally with bony metastatic disease.
 T1 SAGITAL
 T1 STIR SAGITAL
 T1 AXIAL
 T1 SAGITAL POST CONTRAST
T1 AXIAL POST CONTRAST

MRI Trachea Tumor

Tumors of the trachea sometimes hard to diagnose as many patients don't realize they have some pathological reason for their problems so they do not immediately go to the doctor.  Sometimes tumors of the trachea prevent people from swallowing or breathing easily as the tumor may be blocking this function.  Most tumors of the trachea are malignant, but fortunately these tumors occur very infrequently.  Smoking is a risk factor for these tumors.  Here is a website with valuable information on these types of tumors:  http://emedicine.medscape.com/article/425904-overview

MRI can be used for diagnosis of these tumors.  Ultimately a biopsy would need to be performed, but with excellent soft tissue imaging this is sometimes the first step in diagnosis.  A basic protocol of T1 and T2 imaging with post contrast T1 imaging is pretty much all one needs to image this area.  Usual neck imaging contains axial and coronal imaging, but since this structure is midline, sagital imaging should also be performed.  Attached are some images of this:

 T1 SAG
 T1 COR
 T1 AXIAL
 T1 SAG POST CONTRAST
T1 AXIAL POST CONTRAST

Sunday, October 31, 2010

Aneurysm COW

MRA's of the brain are done for cerebral aneurysms.Some patients with acute ruptures present with a stabbing headache out of nowhere.  Others present with history of headaches in particular areas, eye pain, pulsing or family history of aneurysm.  Sometimes larger aneurysms can be harder to see on MR due to the fact of getting lack of flow in the bulb of the aneurysm.  If flow in the aneurysm is not flowing frequent enough it will not show up on the MRA as well due to the nature of the imaging.  Since brain MRA's are usually done non contrast, this can make a diagnosis difficult.  If a patient has an aneurysm they will usually require surgery and have a coil or clip placed to stop the progression and the possibility of rupture. The following website has great information regarding the whole aspect of cerebral aneurysms:  http://www.ninds.nih.gov/disorders/cerebral_aneurysm/cerebral_aneurysm.htm

The following images are of a middle cerebral brain aneurysm:



Sunday, October 10, 2010

Cavernous Sinus Fistula

A cavernous sinus fistula happens when the internal and external carotid arteries and the cavernous sinus gets their "communication" mixed up.  These patients usually see an eye doctor first with eye pain or proptosis.  Sometimes these happen spontaneously but more often by trauma.  A usual protocol for our facility would be images of the entire brain,but also including:
Pre-contrast of orbits
  • T1 fatsat coronal      
  •  T1 Axial 
  •  thin slice Cor T2 
Post contrast of orbits:
  • Fat sat Axial T1
  • Fat sat Cor T1
  • Fat sat Sagital Oblique (angled with optic nerve) of both orbits

The following web site has some basic information:  http://emedicine.medscape.com/article/1217766-overview

The following images are from a patient with a cavernous sinus fistula right side seen posterior orbit cavity.  You can also see the proptosis in the right eye compared to the left.

T2 Axial
T2 coronal
T1 axial

T1 axial post contrast fatsat

T1 Sagital oblique post contrast fatsat






Sunday, October 3, 2010

Pituitary Microadenomas MRI

Micoradenomas, on MRI imaging, can be seen best by using a pre and post contrast gadolinium enhanced study detailed to the pituitary gland.  Dynamic imaging of the pituitary gland can increase the sensitivity of seeing the microadenoma in some instances.  This article shows some studies related to the sensitivity and specificity of the dynamic imaging.  http://www.endocrinology.org/education/resource/summerschool/2004/ss04/ss04_byr.htm
Many of these patients will present with some kind of metabolic or hormonal imbalance, including, but not limited to:  absence of menstruation, lactating breast, breast development in males, any many other hormone regulated problems.  I have included some imaging of a patient with a microadenoma on the right side of the patients pituitary gland, displacing the infundibulum slightly to the patients left.  I have also included a dynamic image showing the actual absence of contrast enhancement as the pituitary gland enhances.

T1 Coronal pre contrast

T1 Coronal post contrast

T1 Sagital pre contrast

T1 Sagital post contrast

Dynamic Coronal about 30 seconds post injection


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.