Michael F. Hartshorne

Scintigraphic appearance of the piriformis muscle syndrome.

This is the first report in the nuclear medicine literature of the scintigraphic appearance of the piriformis muscle syndrome. This syndrome previously has been thought to be a purely clinical diagnosis and imaging modalities have been ignored. However, its confusing clinical presentation can lead to unnecessary surgical exploration. This case is presented to illustrate the characteristic scintigraphic pattern and suggest the role of nuclear medicine scanning in establishing the diagnosis.

Radionuclide evaluation of lung trauma

Nuclear medicine imaging procedures can play a significant role in evaluating the pulmonary complications that are seen in trauma patients. A quantitative method for measuring increased pulmonary capillary permeability that uses Tc-99m HSA allows early diagnosis of acute respiratory distress syndrome (ARDS) and accurately differentiates this condition from pneumonia or cardiogenic pulmonary edema. This technique may be of great value in following the response to therapy. The use of 133Xe to diagnose inhalation injury remains an important diagnostic tool, particularly at hospitals with specialized burn units. Regional decreases in ventilation-perfusion images reliably localize aspirated foreign bodies. Radionuclide techniques that are used to demonstrate gastropulmonary aspiration remain controversial and require further clinical evaluation. Pulmonary perfusion imaging, although nonspecific, may provide the earliest clue for correct diagnosis of fat embolism, air embolism, contusion, or laceration. Furthermore, the possibility of perfusion abnormality due to these uncommon conditions must be remembered whenever trauma patients are evaluated for pulmonary thromboembolism with scintigraphy. Occasionally, liver or spleen scintigraphy may be the most appropriate procedure when penetrating chest trauma also involves these subdiaphragmatic organs.

Biliary scintigraphy. The "hot rim" sign.

A new cholescintigraphic finding, the “hot rim” sign, is reported in a case of acute cholecystitis. Local inflammation in the gallbladder fossa may be the cause of this phenomenon.

Patterns of intestinal activity with Meckel's scintigraphy

Three patterns of intestinal activity were noted in a review of 64 patients studied with Tc-99m sodium pertechnetate for suspected Meckels diverticulum: no bowel activity seen (37.5%), bowel activity visualized after stomach activity (39.1%), and diffuse bowel activity seen simultaneously with stomach activity (23.4%). The latter pattern, which is relatively common, could mask a true Meckels diverticulum and lead to either a false-negative or indeterminate diagnosis. A series of 10 dogs was also studied to evaluate the effects of fasting and feeding on the intestinal pattern. No definite relationship was observed.

Fourier phase analysis in non-cyclic dynamic studies.

Single harmonic Fourier amplitude and phase (FA/P) analyses of 129 radionuclide angiographic (RNA) studies were found to reflect accurately the sequence and quantity of perfusion determined in the independently interpreted RNA studies. In addition, the anatomic detailing in peripheral studies (hands, feet, etc.) was considered superior to that obtained in RNA studies.

Another use for the seven-pinhole collimator. Routine nontomographic imaging of the thyroid

Relatively few seven-pinhole collimator systems purchased within the last three years are still in routine use. This paper describes a nontomographic use of the collimator for thyroid scanning. One Image is obtained which simultaneously shows seven different projections of the thyroid gland. The diagnosis of thyroid abnormalities can frequently be made from this single composite image without the requirement for additional images. Further information can be obtained when needed by computer processing the image into tomographic slices.

Chest radionuclide angiography in the evaluation of pulmonary masses

A retrospective analysis of 104 chest radionuclude angiography (CRNA) studies establishes the utility of this procedure in the evaluation of pulmonary malignancies and benign masses. Remarkable abnormalities in the perfusion of the lungs were identified in 36 (58%) of 62 cases that were not predictably normal or predictably abnormal form the clinical setting. While 60 of these 62 cases involved malignancy being evaluated for metastases, only 21 (34%) had metastases Identified by radionuclide bone or liver-spleen scintigraphy. In addition to diagnosis of superior vena cava obstruction, the CRNA may have a more frequent application as an adjunct to routine scintigraphic studies directed to the identification of metastatic disease.

LEFT VENTRICULAR VOLUMES FROM SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY (SPECT)

A prospective study was performed in 25 patients, comparing SPECT left ventricular (LV) end-diastolic (ED) volume (V) to that of contrast ventriculography (ANGIO). SPECT examination utilized 25 mCi Tc-99m RBC labeled in vivo. Sixty images were acquired with a Picker Dyna Camera 5 over 180° from RAO to LPO utilizing a 50 msec ED window. The 30-second images were preprocessed using a 5x5 spatial filter with a cutoff of 0.10 and then reconstructed into transaxial slices by filtered back-projection utilizing a low resolution proprietary filter. The apex and base of the LV were determined by review of additional long-axis and short-axis slice reconstructions. LVEDV was subsequently calculated from count-corrected regions of interest (ROIs) generated about the transaxial LV slices. All patients underwent contrast ventriculography (ANGIO) within 72 hours of the SPECT study. The correlation coefficient between SPECT and ANGIO LVEDV over a range of 87 to 506 cc was 0.97 with a standard error of the estimate (SEE) of 23 cc. We conclude that SPECT allows for noninvasive and accurate determination of LVEDV without the need for blood sample counting or assumptions about LV geometry and chest wall attenuation.

Computer edge displays for cardiac wall motion evaluation.

Several computer display techniques in both black and white and color are described. Use of such techniques improves the qualitative evaluation of ECG-gated cardiac blood pool studies, especially by less experienced observers. Detection of wall motion at the interface between the myocardial wall and the labeled blood within the cardiac chambers is greatly enhanced. No additional equipment nor computer processing time is required to use these display schemes.