The specific scintigraphic pattern of "shin splints in the lower leg": concise communication.

The clinical entity, "shin splints," is now being recognized, and more specifically characterized by the findings of exercise-induced pain and tenderness to palpation along the posterior medial border of the tibia. In this prospective study, ten patients with this syndrome were evaluated using three-phase bone scintigrams, and a specific scintigraphic pattern was determined. Radionuclide angiograms and blood-pool images were all normal. On delayed images, tibial lesions involved the posterior cortex, were longitudinally oriented, were long, involving one third of the length of the bone, and often showed varying tracer uptake along that length. Obtaining both lateral and medial views was crucial. The location of activity suggested that this entity is related to the soleus muscle. These scintigraphic findings can be used to differentiate shin splints from stress fractures or other conditions causing pain in the lower leg in athletes.

Optimal number of views in 360 degrees SPECT imaging.

UNLABELLED: This study examined SPECT-reconstructed image quality as a function of the number of views, and determined the minimum number of views necessary to remove aliasing artifacts in 360 degrees SPECT. METHODS: Computer simulation was performed using a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-beam collimator with and without photon attenuation. RESULTS: In 360 degrees SPECT, aliasing artifacts were reduced by changing the number of views from an even number 16 to its neighboring odd numbers 15 or 17, from 32 to 31 or 33 and from 64 to 63 or 65. Image quality of 15 or 17 views, 31 or 33 views and 63 or 65 views was similar to that of 32, 64 and 128 views, respectively. CONCLUSION: Replacing an even number of views by its neighboring odd numbers in 360 degrees SPECT significantly decreased aliasing artifacts. Thirty-one or 33 views are sufficient to remove most of the aliasing artifacts in 360 degrees SPECT with a matrix of 64 x 64 pixels. This method can be applied to fast 360 degrees SPECT since fewer views are used.

Correlation of radionuclide imaging and diagnostic ultrasound in scrotal diseases.

A retrospective study was performed to evaluate the comparative usefulness of scrotal ultrasound imaging (SU) and radionuclide scrotal imaging (RSI) in 46 patients. The final diagnosis included four late phase and one early testicular torsion (TT), 11 acute epididymitis (AE), four subacute epididymitis (SE), six malignant tumors, ten hydroceles or other cystic lesions, and ten miscellaneous lesions. In patients with scrotal pain, 3/4 with late phase TT were correctly diagnosed by SU, while one with early TT and 11/15 with AE or SE were not diagnosed. All of them were correctly diagnosed with RSI except one with scrotal cyst. SU was able to separate cystic masses (n = 10) from solid masses (n = 9), but could not separate malignant from benign lesions. RSI had difficulty in separating cystic from solid lesions. We concluded that SU is useful in patients with scrotal mass to separate solid from cystic lesions. However, SU is unable to differentiate acute epididymitis from early testicular torsion. Therefore, in patients with acute scrotal pain, RSI should still be the first study performed.

Morphine augmentation increases gallbladder visualization in patients pretreated with cholecystokinin.

UNLABELLED: The purpose of this study was to determine if a combination of cholecystokinin (CCK) pretreatment followed by morphine augmentation improved the detection of cystic duct patency compared with CCK pretreatment only. METHODS: One hundred fifty-five patients with suspected acute cholecystitis had scintigraphy performed with 185-481 MBq (5-13 mCi) 99mTc-mebrofenin adjusted to the patients' total bilirubin levels. All patients were pretreated with 0.02 microgram/kg sincalide injected intravenously over 3-5 min. Sequential imaging was performed until gallbladder activity was identified or up to 90 min postinjection of mebrofenin. If no gallbladder was identified, a second dose of mebrofenin was given as necessary to have tracer in the biliary system. Then, 0.04 mg/kg intravenous morphine sulfate was administered, followed by imaging for up to 30 min or until gallbladder visualization. RESULTS: Twenty-eight percent (43/155) of the patients pretreated with CCK had nonvisualization of the gallbladder at 90 min postinjection of radiotracer. After intravenous morphine, the gallbladder was identified in 42% (18/43) of these patients (p = 0.0001). CONCLUSION: Hepatobiliary imaging with CCK pretreatment and imaging for 90 min was insufficient to identify all patent cystic ducts. Morphine augmentation significantly increased the frequency of gallbladder visualization in patients pretreated with CCK.

Comparison of continuous step-and-shoot versus step-and-shoot acquisition SPECT.

UNLABELLED: This study compared the quality of SPECT images obtained with step-and-shoot mode (SSM) and continuous step-and-shoot mode (CSSM). METHODS: Computer simulations of SSM and CSSM were performed with a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-hole collimator. The effects of noise and photon attenuation were examined. RESULTS: Without noise and without attenuation, small structures in reconstructed images obtained using fast CSSM (less than 4 sec per view plus the moving time from one view to the next) were slightly blurred and rotated in the opposite direction of detector motion. With both noise and attenuation, these artifacts were not visible, and the image quality obtained from CSSM, especially from fast CSSM, was improved as compared to that resulting from the corresponding SSM due to the increasing number of counts. The improvement of image quality became less significant with increasing acquisition time and in the presence of attenuation. CONCLUSION: For fast SPECT, CSSM provided better image quality than the corresponding SSM, especially when attenuation effects were not present. For relatively long time SPECT without attenuation compensation that is typical for clinical studies, the image quality of CSSM was similar to that of SSM.

Planar and high-resolution SPECT bone imaging in the diagnosis of facet syndrome.

UNLABELLED: This study's goals were to determine the appearance of potentially symptomatic facet joints on planar and high-resolution SPECT radionuclide bone imaging, relate the relative sensitivity of the two techniques and assess the predictive value in a clinical setting. METHODS: Fifty-eight consecutive patients referred with a diagnosis of possible facet syndrome were imaged during the same visit using both a well-established planar and a SPECT technique developed to emphasize high spatial resolution. The standard of reference included facet injections with a marcaine and steroid mixture, with review of a pain journal completed by the patient included in the followup criteria. RESULTS: In the 43 patients comprising the final study group, 7 were diagnosed with facet syndrome, 5 with abnormal planar images and 7 with abnormal SPECT images. A total of 10 facet joints with abnormal increased uptake were seen on SPECT which were not demonstrated on planar imaging. There was high sensitivity (100% SPECT, 71% planar), but somewhat lower specificity (71% SPECT, 76% planar). The negative predictive value was high (100% SPECT, 93% planar). Radionuclide bone imaging additionally discovered a nonfacet joint etiology for patient symptoms in 16 of the 43 patients. CONCLUSION: Higher spatial resolution SPECT images are better accepted by referring physicians who correlate them with CT or MR images. The high negative predictive value allows radionuclide bone imaging to be used to select appropriate patients to undergo the invasive facet injection procedure.

Comparison of parathyroid imaging with technetium-99m-pertechnetate/sestamibi subtraction, double-phase technetium-99m-sestamibi and technetium-99m-sestamibi SPECT.

UNLABELLED: The ability of 99mTc-pertechnetate/sestamibi subtraction, double-phase 99mTc-sestamibi and 99mTc-sestamibi SPECT imaging to localize abnormal parathyroid tissue was compared. METHODS: Fifty-five consecutive patients had parathyroid imaging before surgery for hyperparathyroidism. Imaging consisted of 99mTc-pertechnetate pinhole images of the neck followed by 99mTc-sestamibi pinhole images of the neck and parallel-hole images of the neck and chest (early images). Within 2.5-4.0 hr later pinhole images of the neck, parallel-hole and SPECT images of the neck and chest were obtained (late images). Nodular foci of increased sestamibi activity were considered abnormal. RESULTS: The sensitivity for abnormal parathyroid glands by visual comparison of early images and pertechnetate images was 72%-75%, late images and pertechnetate images was 73%-78% and double-phase (early and late) sestamibi images was 62%-65%; computer subtraction of pertechnetate from early images was 71%-74%; and SPECT imaging was 79%. The sensitivity for parathyroid adenomas was 89%-98%, while the sensitivity for hyperplastic parathyroid glands was only 47%-58%. CONCLUSION: Late imaging, computer subtraction and SPECT may not be necessary since they provided only marginal improvements on visual comparison of early sestamibi with pertechnetate images. Double-phase sestamibi imaging was less sensitive, so baseline thyroid imaging with pertechnetate is recommended.

The Gamut approach to scintigram interpretation--diagnostic aid and teaching method.

A Gamut is defined as a complete list of anything. As utilized here, it indicates a complete list of the possible causes of a particular scintigram finding. The procedure for developing a Gamut is discussed, ant its use as a tool for instructing residents in nuclear medicine is described. Sample Gamuts are presented and the Gamut approach to scintigram differential diagnosis is described.

Reflex sympathetic dystrophy: diagnostic controversies.

Reflex sympathetic dystrophy, (RSD) is a complex physiologic response of the body to an external stimulus resulting in sympathetically mediated, usually nonanatomic pain, which is out of proportion to the inciting event or expected healing response. This complex entity has been the focus of much investigation, leading however to somewhat confusing and conflicting results and theories about the etiology and pathophysiology. There is even significant conflict about what characteristics define the clinical entity called RSD, and if these characteristics vary with the specific site of involvement. We have examined the current literature regarding these fundamental conflicts, and in addition we have evaluated the current controversies surrounding the role of Three Phase Radionuclide Bone Imaging (TPBI) for diagnosis, prognosis, and patient management. These controversies include the role of scintigraphy, the various criteria for scintigraphic diagnosis, and the reported variations in sensitivity and specificity of TPBI in RSD. We have examined several factors that may have affected these results, and potentially underestimated the value of scintigraphy in the diagnosis of RSD. In addition to the heterogeneous patient populations used to establish the diagnosis by different subspecialty physicians, these factors include duration of patient's symptoms, age of the patient population evaluated, location of the disease, and the varying scintigraphic scan interpretation criteria used.

The role of single photon emission computed tomography in bone imaging.

Single photon emission computed tomography (SPECT) of the bone is the second most frequently performed SPECT examination in routine nuclear medicine practice, with cardiac SPECT being the most frequent. Compared with planar scintigraphy, SPECT increases image contrast and improves lesion detection and localization. Studies have documented the unique diagnostic information provided by SPECT, particularly for avascular necrosis of the femoral head, in patients with back pain, for the differential diagnosis between malignant and benign spinal lesions, in the detection of metastatic cancer in the spine, for the diagnosis of temporomandibular joint internal derangement, and for the evaluation of acute and chronic knee pain. Although less rigorously documented, SPECT is being increasingly used in all types of situations that demand more precise anatomic localization of abnormal tracer uptake. The effectiveness of bone SPECT increases with the selection of the proper collimator, which allows one to acquire adequate counts and minimize the patient-to-detector distance. Low-energy, ultrahigh-resolution or high-resolution collimation is preferred over all-purpose collimators. Multihead gamma cameras can increase the counts obtained or shorten acquisition time, making SPECT acquisitions more practical in busy departments and also increasing image quality compared with single-head cameras. Iterative reconstruction, with the use of ordered subsets estimation maximization, provides better quality images than classical filtered back projection algorithms. Three-dimensional image analysis often aids lesion localization.

Technical considerations for optimal orthopedic imaging.

Over the past 25 years bone scintigraphy has played an essential role in most Nuclear Medicine departments, accounting for 25% to 60% of the patient volumes. No longer is every bone scan ordered as part of a metastatic workup. Today radionuclide bone imaging (RNBI) is included in most orthopedic diagnostic pathways. It is necessary to optimize the bone scan procedure to be sensitive, to carefully localize abnormal uptake for diagnosis, to correlate the bone scans, plain radiographs, computed tomographic (CT) scans, and magnetic resonance (MR) scans that accompany the patient, and to be precise in reporting a final impression. This can be done through meticulous attention to the image acquisition so that it encompasses not only equipment specifications and acquisition parameters, but also patient history, preparation, imaging protocols, positioning, and image correlation. The importance of these considerations, the rationale to explain them, and suggested guidelines for their implementation will be discussed in this article.

Current status of radionuclide scrotal imaging.

Scrotal imaging with technetium-99m sodium pertechnetate consists of a radionuclide angiogram and static scrotal scans. Utilization of this study in patients presenting with an acute scrotum can dramatically reduce the number of surgical explorations for acute epididymitis. It can also aid in other aspects of differential diagnosis in patients presenting with either an acutely enlarged and/or painful scrotum or a scrotal mass. Ambiguities in previous descriptions of perfusion through the spermatic and extraspermatic cord vessels are described and distinguished from scrotal perfusion. The clinical and scintigraphic spectrum of testicular torsion, including spontaneous detorsion, early acute testicular torsion, midphase testicular torsion, and late phase or "missed testicular torsion," is discussed and illustrated. The variety of patterns seen in acute epididymitis, including lateral and medial epididymal location, and focal epididymitis are described, as is the appearance of hydrocele as both a primary and secondary entity. The relationship of scrotal imaging to the overall clinical presentation and evaluation of these patients is emphasized in testicular torsion, torsion of the testicular appendages, epididymitis, abscess, trauma, tumor, spermatocele, and varicocele. The techniques, clinical utility, and relationship to radionuclide imaging of Doppler ultrasound and gray scale ultrasound scanning are reviewed. Doppler ultrasound results in many false negative studies in testicular torsion. Gray scale ultrasound is useful in clarifying the nature of scrotal masses.

Acute appendicitis presenting as acute left scrotal pain: diagnostic considerations.

To our knowledge this is the first case of acute perforated appendicitis presenting as acute left scrotal pain described in the literature. In addition, this case involved a unique false positive radionuclide scrotal scan for testicular torsion, which is also reported and discussed for the first time.

Bone scintigraphy in skeletal trauma.

This article emphasizes the usefulness of radionuclide bone imaging (RNBI) throughout the clinical spectrum of osseous trauma and relates RNBI to the other imaging modalities available. Acute, stress, insufficiency, avulsion, and occult fracture detection are discussed and illustrated. Other traumatic lesions including the bone bruise, shin splints, tendinitis and epiphyseal injuries are included. Biomechanical lesions, the result of more chronic low level repetitive stress are discussed in detail, as is the use of RNBI in the detection of post-traumatic sequela such as the reflex sympathetic dystrophy syndrome. Technical aspects of RNBI are considered in the context of producing the quality of diagnostic images necessary for clinically complete consultative reporting.

Measurement of distal forearm bone mineral density: can different forearm segments be used interchangeably ?

Many different forearm sites have been used for the measurement of bone mineral density (BMD) and prediction of risk of future fracture among community dwelling populations. In populations where bone densitometry of peripheral sites may be the most cost effective and practical means of measuring BMD, such as the nursing home population, knowing the characteristics of forearm BMD measures would be beneficial. The purpose of this study was to assess the relationship of four common commercially available measures to each other and to estimate the inter- and intrarater reliability of the measures in a sample of nursing home residents as a first step toward identifying appropriate forearm measurement sites. These sites were the distal radius, the distal ulna, a composite of the distal radius and distal ulna, and the ultra distal radius. BMD measurements on 48 nursing home patients were obtained using single X-ray absorptiometry. Inter- and intrarater reliability was excellent at all four sites (interclass correlation coefficients > 0. 85). Moderate to high correlations (0.84-0.91) between the distal radius and ultra distal radius sites of the forearm suggest that these measures may be interchangeable. Although not directly assessed here, differences in bone composition among forearm sites may partially explain moderate rather than high correlations between sites and may affect the ability of each site to predict future fractures. Thus, different forearm sites may be used interchangeably for diagnostic purposes; however, the prognostic value of each site remains unknown.

The soleus syndrome. A cause of medial tibial stress (shin splints).

Radionuclide bone scans have demonstrated linear uptake along the posterior medial border of the tibia in patients with shin splints. This area was investigated by anatomical dissection (14 human cadavers), electromyographic (EMG) and muscle stimulation studies (10 patients), and open biopsy (1 patient). Histologically, the increased metabolic activity manifested on the radionuclide scan is due to a periostitis with new bone formation. The soleus muscle and its investing fascia are anatomically and biomechanically implicated in the production of these stress changes, particularly when the heel is in the pronated position. The soleus muscle and fascia form a tough "soleus bridge" over the deep compartment which is thought to be important in patients requiring surgical decompression.

Preoperative cardiac risk assessment with adenosine stress dual-isotope myocardial single-photon emission computed tomography.

BACKGROUND: Previous studies have demonstrated that pharmacologic stress thallium-201 (201Tl) myocardial scintigraphy is a useful tool to evaluate preoperative cardiac risk. HYPOTHESIS: The purpose of this study was to assess the utility of adenosine stress dual-isotope [rest 201Tl/stress technetium-99m (99mTc) sestamibi] myocardial single-photon emission computed tomography (SPECT) in predicting the risk of perioperative cardiac events (unstable angina, myocardial infarction, cardiac death) in patients undergoing major noncardiac surgery. METHODS: We evaluated 43 consecutive patients (20 men, 23 women, mean age 64 years, range 30-83 years) within 8 weeks prior to major noncardiac surgery requiring general anesthesia. SPECT imaging was performed with 111 MBq (3 mCi) 201Tl at rest and 925 MBq (25 mCi)99mTc sestamibi during adenosine stress. RESULTS: Of the 43 patients, 15 (35%) had stress-induced ischemia and 28 (65%) did not. Perioperative cardiac events occurred in 4 (27%) of the 15 patients with stress-induced ischemia (2 unstable angina, 2 nonfatal myocardial infarctions) and in none of the 28 patients without inducible ischemia (p = 0.02). CONCLUSION: Adenosine stress dual-isotope myocardial SPECT is useful in determining the preoperative cardiac risk of patients undergoing major noncardiac surgery.

Effects of the attenuation map used in the Chang algorithm on quantitative SPECT results.

OBJECTIVE: This study examined the effects on SPECT quantitation caused by erroneous size and position of the attenuation map and inaccurate pixel size used in the Chang algorithm. METHODS: Projection data of a three-dimensional head phantom were simulated with a uniform attenuation coefficient of 0.15/cm for the inside of the phantom. Images were reconstructed using the filtered backprojection algorithm without attenuation compensation and the Chang algorithm with different attenuation maps. Quantitative comparison then was performed between the reconstructed images and the phantom. RESULTS: The pixel values obtained for noisy data by using the first-order Chang algorithm with an accurate attenuation map were less than 10% different from the true values and the left-right asymmetry was under 5%. Small errors in the geometric parameters of the attenuation map, however, caused considerable quantitative inaccuracy in the reconstructed image. For example, a 0.64-cm error in the size of the map caused 10% deviation from the true value and a 0.64-cm shift of the position of the map towards the left produced 10% left-right pixel value asymmetry. CONCLUSION: The accuracy of the Chang algorithm critically depends on the geometric parameters. For a uniform attenuator with symmetric geometry, such as the human brain, a true left-right symmetry in the pixel value can be altered significantly by a small error in the geometric parameters, while symmetry can be maintained with no attenuation compensation.

Dual-isotope protocol for indium-111 capromab pendetide monoclonal antibody imaging.

OBJECTIVE: A dual-isotope imaging protocol using 99mTc-labeled red blood cells with 111In capromab pendetide monoclonal antibody imaging for detective and localizing nodal metastasis in prostate cancer is described. METHODS: This protocol involves a single SPECT acquisition that is less time consuming and more comfortable for the patient than the currently recommended method, which requires two separate SPECT acquisitions performed on different days. RESULTS: Forty patients were studied with the dual-isotope protocol. Preliminary data suggest increased accuracy compared with the single-isotope technique. CONCLUSION: The dual-isotope technique assures the precise image registration needed for accurate comparison of blood pool and pelvic lymph node activity that is required for confident and accurate image interpretation.

Life-threatening hemorrhage of an unanticipated superficial circumflex iliac artery origin imaged with Tc-99m-labeled erythrocytes.

The authors report, for the first time, the nuclear medicine diagnosis of extraperitoneal bleeding that originated from the superficial circumflex iliac artery and review the critical role of dynamic nuclear imaging techniques in the localization of sites of nonenteric hemorrhage. Dynamic imaging techniques using Tc-99m-labeled erythrocytes played a critical role in the localization of an extraperitoneal bleeding site near the entrance site of a Jackson-Pratt drain. Localization of the site remained undiagnosed before nuclear imaging despite two exploratory laparotomies and diagnostic angiography.