Non-osseous abnormalities on bone imaging

I have always found non-osseous uptake of skeletal imaging agents to be of interest. In 2003 the Journal of Nuclear Medicine Technology published an excellent article on non-osseous abnormalities. During my years of teaching, students have brought in many examples which I wish to share...

In the area of altered biodistribution, whether due to faulty preparation or pharmaceutical interference:

Free technetium due to the presence of air in the container during preparation will lead to increased uptake of unbound technetium in the stomach, gastrointestinal tract, thyroid and salivary glands...

It was noted in the article that drug interaction with diphosphonates used in treatment of osteoporosis can lead to decreased skeletal uptake.

Male on hemodialysis, with a complaint of back pain. Findings include decreased skeletal uptake of the radiopharmaceutical. The patient medical history includes administration of PhosLo (calcium acetate tablets) 3-times a day with meals indicated for patients with hyperphosphatemia. The retention of phosphates in patients with renal insufficiency plays a role in causing secondary hyperparathyroidism. This scan was compared to another patient scanned with radiopharmaceutical from the same bath to verify this was not associated with poor radiopharmaceutical preparation. Due to the patient's condition his attending physician would not take him off the PhosLo for a repeat scan...

Uptake related to the urinary system, is the most common finding of non-osseous uptake. Findings include: dilated, obstructed ureters, hydronephrosis, renal cysts:

80-y female, history of melanoma, complains of back pain. Findings include a mild right side hydronephrosis, with a dilated ureter noted in the pelvis...

91-y female, fell 3 days prior to scan, complains of left hip pain. Findings include marked hydronephrosis of both kidneys with dilatation of both ureters. Possible obstructive uropathy near the urinary bladder...

25-y male, with history of right renal abscess. Skeletal imaging was ordered for a complaint of right side flank pain to rule out osteomyelitis. Findings include a photon deficient 4cm area in the upper pole of the right kidney consistent with a cysts, tumor or abscess...

38-y female with a history of right lung carcinoma. Findings include poorly defined uptake at the areas superior to both kidneys, suggestive of metastatic disease in the adrenal glands...

Soft tissue uptake may be found in various areas due to soft tissue calcification, which may point to specific pathology:

51-y female with a history of breast cancer. Findings include mild diffuse uptake in the liver, of uncertain clinical significance. The likelihood of interference of additional imaging procedures was reviewed. The patient did not have a prior liver scan, which would have been performed by calculation on Sunday when the department was closed for routine imaging. Gallium-67 for soft tissue imaging would present with considerable background activity. The pattern of uptake is not suggestive of hepatic metastatic disease, but may suggest necrosis or microcalcification...

Elderly female fell out of bed onto her left side, complains of left hip pain. Findings include increased cardiac uptake as well as uptake in several left ribs suggestive of cardiac contusion and rib fractures related to trauma...

76-y male with a history of right nephrectomy, on hemodialysis, complains of low back pain. Findings include cardiac uptake related to calcification of the pericardium, which was seen on a recent CT of the chest. This may be an indication of metastatic calcification, which can be seen in secondary parathyroid hyperplasia...

46-y male with a recent finding of multiple myeloma. Findings include intense uptake in the region of the myocardium, most likely secondary to calcified pericarditis, however diffuse myocardial infarction may also have this appearance...

Female with documented history of hypercalcemia. Findings include diffuse uptake of the the radiopharmaceutical in both lungs. This pattern of uptake has been implicated with hypercalcemia and related to metastatic calcification...

Thanks to Heny Shah, Dolores Ambrosy, Corrine Zenkel, 

WB Skeletal Imaging - motion artifact

Whole body bone scan obtained 2 hours following the intravenous injection of Tc99m MDP.

Older cameras used to perform whole body images by scanning at the right side of the body head-to-toe, moving the table and scanning the left side of the body toe-to-head. This often produced a zipper line done the middle of the body where the images were joined. If the patient moved or the camera and table were not properly aligned the images could result in separation of the images or mis-registration.

Newer systems have the ability for single-pass imaging, which eliminates the zipper and mis-registration problems. The single-pass technique although does not always allow for inclusion of the patients arms in the field of view.

On this particular image the patient noticeably moved their head from right to left resulting in the alien feature of a twin lobed cranium.

The practice of this institution was to perform a whole body posterior image with spot shots of the anterior skull chest, abdomen, and pelvis. 

Although this is older technology, newer camera do not require a double pass for the whole body image, I have always enjoyed the "alien" presence in this image..

WB Skeletal Imaging - Contamination

Clinical History: 73 year old female with low back pain.

Technique: 3phase and whole body bone scan performed following injection of 23 mCi MDP.

Findings: The dynamic blood flow study and immediate post injection scan of the lower back demonstrate no evidence of a focally increased blood flow of increased vascularity. Bone imagings from the head to toes demonstrate a slightly increased tracer uptake involving the lower lumbar spine at the level of L4 and L5, probably due to degenerative bone and joint disease. Slightly increased tracer uptake involving both shoulder joints, probably non-specific arthritis. No abnormal tracer uptake is noted in the sacrum and coccyx.

Slightly increased tracer uptake involving patient's boots. The patient was on lasix, and urinated through her pantyhose. She went home and changed her hose prior to imaging. She did not change her boots, therefore only the boots show contamination and not her hosiery.

Thanks to Y.H. Park, MD, Meredith Smela, Debbie Reed

Stress Fracture - Shin Splints

A stress fracture is an overuse injury, one of the most common injuries in sports, especially the weight bearing bones of the lower extremities.

MRI has surpassed skeletal scintigraphy showing equal sensitivity, but a higher specificity, while providing improved anatomical detail.  However, there is still reason for obtaining a three phase bone scan for lower extremity trauma when MRI may be inconclusive or for patients who can not handle the MRI scan.

Often a physician will request a 3 phase bone scan for lower leg pain to determine if the pain in a patient's lower extremity is either a stress fracture or trauma, or shin splints (medial tibial stress syndrome).

A stress fracture often occurs as the result of an increasing amount or intensity of pressure during an activity more rapidly than the bone structure can manage. They may also be caused by impact (rapid change in surface hardness), improper equipment (poor foot support in a shoe) and increased physical stress.1

The stress fracture is  a small crack in the bone without displacement. The associated symptom is pain, which subsides with rest.

Delayed skeletal images of a young jogger complaining of lower extremity pain while running. Top images show lateral and medial images, white the lower images show anterior and posterior images of the lower extremities. all views demonstrate a focal area of uptake in the left tibia, consistent with a stress fracture. The area correlated with the patient's focus of pain.

On a 3 phase bone scan the dynamic flow with have increased uptake at the site of injury. The second phase (blood pool, soft tissue) will also have increased uptake associated with edema around the injured site.

The 3rd phase (skeletal image) will again demonstrate increased focal uptake at the site associated with the patient's pain.

The dynamic images and soft tissue phase (not shown) demonstrated no abnormal uptake or early osseous localization.

Anterior delayed image - young female athlete complaining of lower extremity pain for 6 months. MRI was inconclusive for stress fracture, but positive for a stress injury.

Right lateral and left medial image demonstrates linear uptake along the tibial shaft consistent with 

shin splints. No evidence of fracture.

The shin splint is an inflammation of the muscle, tendons and bone tissue around the tibia, usually along the inner border of the tibia where the muscle attaches to the bone. Shin splints may be the result of improper footwear, increase in workload on the lower extremities, changes in surface conditions. All the same causes as a possible stress fracture.

The patient complaint is pain, which may be associated with mild swelling, which subsides with rest.

On a 3 phase bone scan their may be some activity associated with edema on the flow or soft tissue phases. However the delayed skeletal image will not have a focal point of activity, but increased uptake seen along the tibia.

An advantage of utilizing the bone scan over MRI is the ability to image the whole body following injection. Keep in mind that patients complaining of lower extremity pain may have associated hip pain.

Skeletal Imaging - Scapula lesion

Skeletal Imaging - positioning for a scapula lesion.

  

Clinical history: Female with a history of breast cancer. Bone scan requested to rule out metastases. Patient complained of left shoulder pain.

Technique: The patient received 25 mCi Tc MDP and whole body and spot shots were obtained at 3 hours post injection.

Findings: The study was compared to a previous bone scan acquired 1-year earlier. Findings demonstrate an area of increased uptake at the inferior angle of the left scapula. The finding was considered to be a stable metastatic lesion that was also seen on a CT and described as mixed sclerotic and lytic lesion.

No other abnormalities were noted..

Posterior whole body view shown.

Additional images were acquired in the left anterior oblique view, to demonstrate the lesion was truly in the scapula, not in the ribs. In this case the lesion still overlies the ribs making true determination difficult.

An additional posterior view was obtained with the patients arms raised over her head. This movement moves the scapula outward providing separation of the scapula from the posterior rib cage.