Radionuclide Images Research Articles

99mTechnetium-Fibrinogen Lung Scanning in Canine Lung Contusion

To detect experimentally induced acute lung contusion in anesthetized dogs, serial radionuclide images of the lung were recorded following intravenous infusion of 99mTc-labelled human fibrinogen (Tc-HF). The accumulation of Tc-HF in canine lungs was serially quantitated for up to 20 hours after lung contusion. A contusion (#1) was produced in one lung, Tc-HF was injected IV after 15 minutes, and 75 minutes later a contralateral lung contusion (#2) was produced in a series of 14 dogs. At autopsy the excised lungs were scanned, sectioned, and counted for radioactivity. Radiolabelled fibrinogen accumulated within 2-4 minutes of contusion #2 and remained stable over the next 20 hours in 14 dogs; contusion #1 was barely visible in four dogs. Lung Tc-HF activity in the central region of contusion #2 remained sixfold higher than in normal lung tissue. These data suggest that following lung contusion, fibrinogen deposition occurs rapidly and remains stable over a 20-hour interval of observation.

The use of three-phase radionuclide bone scanning in the diagnosis of reflex sympathetic dystrophy

One hundred forty-five consecutive three-phase radionuclide bone scans were reviewed. One hundred two of these were performed to evaluate pain in the hand. Of these, 23 patients clinically had reflex sympathetic dystrophy (RSD). The hand scans were performed by the three-phase technique. Phase I is a radionuclide angiogram. Phase II is the blood pool or tissue phase. Phase III consists of delayed images obtained 3 to 4 hours after radionuclide injection. Detailed analysis of the 145 three-phase radionuclide bone scans of the hand demonstrated that the diffuse increased tracer uptake in the delayed image (phase III) is diagnostic for RSD, with a sensitivity of 96% and a specificity of 98%. The two early phases (radionuclide angiogram and blood pool) were positive in only 45% and 52% of the RSD patients, respectively. The strictly interpreted delayed radionuclide image is extremely sensitive in the diagnosis of RSD and will facilitate the early diagnosis and subsequent treatment of this syndrome.

Scintigraphic assessment of atrial function in patients with longstanding hypertension.

Right and left atrial function were assessed using Fourier analysis of gated radionuclide images in 14 normal subjects and 50 patients with long-standing essential hypertension. Slopes representing filling and early diastolic emptying were similar for both atria; however, early diastolic emptying of the left atrium was slowed markedly in the hypertensive group (42.6 +/- 18.6 counts/sec., vs. 79 +/- 16 in normal persons; p less than 0.001), implying a reduction in left ventricular compliance. The right ventricular ejection fraction was depressed in hypertensive patients compared with normal subjects (37.1 +/- 6% vs. 43.4 +/- 8.1%; p less than 0.01). These findings may be helpful in understanding the effect of hypertension on the left and right heart and could have prognostic and therapeutic implications as well.

Absolute left ventricular volume by an iterative build-up factor analysis of gated radionuclide images.

A method for determining absolute left ventricular (LV) volumes from radionuclide gated blood-pool (GBP) images was validated in 34 patients. The technique is nongeometric, corrects for tissue attenuation, and uses an experimentally determined set of build-up factors to account for the effects of scatter. Only four parameters are needed to determine LV volumes: the LV count rates from a left anterior oblique (LAO) and a right posterior oblique (RPO) image (180 degrees opposed to the LAO), a venous blood sample, and a patient thickness measurement. A computer algorithm is used to reach an iterative solution to two simultaneous equations that yield LV volumes. Phantom studies showed less than 4% error for volume determinations at all investigated depths. For the patients studied the correlation between volumes obtained by GBP and contrast ventriculography was 0.97 for diastole and 0.96 for systole.

Segmental assessment on ordinary scintigrams and SPECT images of the liver.

By examining the area of defect elucidated on the scintigrams and SPECT (single photon emission computed tomography) images, the extension of the tumor into segments was assessed in cases where the SOL (space-occupying lesion) was determined by other methods. In this study, we followed the Couinaud 's segmentation. As a result, it was found that the segment with a SOL could be diagnosed fairly well on radionuclide images. Some incorrect assumptions were also found about the segments on ordinary scintigrams in previously published articles. These incorrect assumptions have been accepted for a long time. Although we do not deny that TCT (transmission X-ray computed tomography), echography, angiography, etc. are necessary for a precise judgment on liver segment and also that there are some cases in which the segmental assessment of these radionuclide images is impossible, we do believe that this kind of effort will improve the diagnostic capability of the radionuclide images.

Relation between premature ventricular contraction site of origin (defined by radionuclide phase analysis) and subsequent left ventricular function

It has been suggested that the effect of a premature ventricular contraction (PVC) on left ventricular (LV) function depends on the site of origin of the PVC, and that the subsequent impairment of LV performance during a PVC may be more pronounced if baseline LV dysfunction is present. To evaluate these concepts, radionuclide angiographic phase image analysis of spontaneous PVCs was performed after acquisition of images from PVCs alone by a new gating procedure. The sites of the PVCs were localized to 1 of 3 right ventricular (RV) or 5 left ventricular (LV) regions by this method. LV function during PVCs was assessed and compared with baseline by noting the LV ejection fraction (EF) during PVCs, the difference between sinus LVEF and PVC EF, and the normalized PVC EF (PVC EF/sinus EF). Twenty-four patients had LV PVC sites and 19 had RV sites. LV function during a PVC appeared to be independent of either the ventricle of origin of the PVC or a specific site of origin within the ventricles. The resultant PVC ventricular function also appeared independent of sinus LVEF and sinus wall motion abnormalities. In addition, no correlation between coupling interval and any of the variables measured was demonstrated (although extremely short coupling intervals were not evaluated). These data suggest that the effects of PVCs on ventricular performance seen during ventricular ectopy are independent of the site of origin of the PVC, baseline wall motion abnormalities or PVC coupling interval in the population studied.

Tumour localisation in oncology using positron emitting radiopharmaceuticals and a multiwire proportional chamber positron camera; Techniques for 3D deconvolution

Tomographic patient images have been produced with a prototype Multiwire Proportional Chamber (MWPC) Positron Camera built by the Rutherford Laboratory. The volume that may be imaged is 20×20×20 cm 3 limiting patient studies to the skull, brain, thyroid, heart, liver and areas of the skeleton. Typical total count rates of 1–2×10 3 c/s were achieved with 40–80 MBq of injected radionuclide and acceptable clinical images with 0.5–1 million counts were obtained in 15–30 min. The in-plane spatial resolution is 8–10 mm fwhm and the slice width is 2 cm with scattering material present. Longitudinal tomograms are reconstructed by back projection, followed by 2D deconvolution of the point source response function (PSRF) and Fourier filtering of the backprojected images to remove in-plane noise. The clinical images presented were produced in a clinical trial at the Royal Marsden Hospital, Sutton. The images generated in this way, whilst already clinically useful, suffer from the plane interference common to all methods of longitudinal tomography. A 3D deconvolution technique has been developed which removes much of this interference. The technique is based on dividing the 3D Fourier Transform (FT) of the images by the 3D Transform of the PSRF but relies for its success on selecting a suitable set of “tuning” conditions under which this deconvolution can be successfully attempted in the presence of photon noise. This important tuning conditions are discussed and the improvement in the resulting images is illustrated. Finally the requirements for a clinically useful system are discussed.

RADIONUCLIDE THYROID IMAGING IN 135 CATS WITH HYPERTHYROIDISM*

Thyroid scanning was performed in 135 hyperthyroid cats and 13 normal cats with technetium‐99m as pertechnetate (99mTcO4) or with radioactive iodine (131I). Of the hyperthyroid cats, enlargement and increased radionuclide accumulation were found in one thyroid lobe in 38 (27%) and in both lobes in 97 (73%). In two hyperthyroid cats with thyroid carcinoma, extension of tumor into the thoracic cavity was detected. In normal and hyperthyroid cats the radionuclide images produced with 99mTcO4 and 131I were similar; however, the quality of the 99mTcO4 scans was usually better than that of the 131I scans.

Nuclear medicine in hepatic mass lesions

I N RADIONUCLIDE images of the liver performed by the usual techniques, ie, multiple static views obtained with a radiolabeled colloid such as Tc-99m sulfur colloid, mass lesions appear essentially the same regardless of the pathology. Malignant and benign tumors, cysts, infarcts, abscesses, physical trauma, and certain vascular tumors all present as foci of decreased radioactivity. Greater specificity of pathologic diagnosis is usually made by inference. When hepatic imaging with radioactive tracers was the only noninvasive imaging modality available, these studies were used extensively with an acceptable level of confidence. Although development and progressive sophistication of transmission CT and ultrasonography (US) demonstrated the limitations of two-dimensional planar imaging with radiotracers, the positive contributions were not emphasized. We in nuclear medicine must accept the responsibility for instituting advances in the development of radiotracers, imaging instrumentation, and more sophisticated techniques to improve the data obtained from hepatic radionuclide studies. The observation made by Lunia et al’ in 1975 remains valid to some extent today: the diagnostic accuracy of static liver studies has not improved remarkably.’ In many respects liver imaging as performed now is similar to earlier methods that used radioactive gold colloid and rectilinear scanning equipment. Through innovative approaches and the application of techniques customized to a particular clinical problem, radionuclide hepatic scintigraphy can be used, both as a primary method for detecting a mass lesion and as a tool for better characterization of the lesion. It is now possible

Causes of focal hepatic portal defect on 99mTc-sulfur colloid scintigraphy

B ECAUSE OF A mass lesion in the left lung, a 76-yr-old woman was referred for a 99mTc-sulfur colloid liver/spleen study to rule out metastatic disease. The rapid sequential flow study (Fig. 1) revealed a focal area of decreased activity in the mid-inferior border of the liver and a 'halo surrounding the cardiac blood pool. On the static images there was a prominent portahepatis, and visualization of bone marrow (Fig. 2). The wide separation between the cardiac blood pool activity and liver activity suggested pericardial effusion, which correlated with the suddenly enlarged cardiac shadow by chest radiograph. Subsequent echocardiogram also indicated a large anterior and posterior pericardial effusion. The patient expired on the tenth hospital day. At autopsy, there was a poorly differentiated adenocarcinoma of the left lung with metastasis to the brain, heart, and pericardium. The pericardial cavity contained 700 ml of blood fluid. The liver showed only severe acute and chronic passive congestion with no evidence of metastasis and the normal sized gallbladder was located posteriorly, between the right and quadrate lobes. No abnormalities were observed in the inferior portion of the liver or the region of the porta-hepatis, however, a marked concavity was noted inferiorly between the right and left hepatic lobes (Fig. 3). This concavity correlated with the defect noted on the hepatic radionuclide image (Fig. 2). Focal defects in porta-hepatis and gallbladder regions on 99mTc-sulfur colloid scintigraphy have

“Cold” area around a transplanted kidney

A 27-yr-old male was admitted to receive a cadaver kidney transplant because of chronic renal failure since age 19. Four years prior he had received a cadaver kidney transplant to his right iliac fossa. That kidney was removed later due to rejection. Immediately after the current operation, radionuclide renal images showed changes of acute tubular necrosis that gradually resolved in time. Three weeks post operation, the patient's serum creatinine concentration increased, and his urine output declined. 99mTc-Glucoheptonate perfusion and delayed static images showed a persistent cold area inferior medial to the lower pole of the transplanted kidney in the left iliac fossa (Figs. 1 and 2). At the same location, the renal ultrasonogram showed a 1 l • 9 x 7 cm fluid collection. Subsequently, a lymphocele was drained surgically.

The Location of Urinary Calculi Using Radionuclide Imaging

Summary— A method of in vivolabeling urinary calculi with 99mTc-methylene diphosphonate is described. This enables a radionuclide image of the stones to be produced and permits their location at operation by means of a small scintillation detector. The degree of uptake of the radiopharmaceutical on renal stones appears to depend on a number of factors, particularly the chemical composition of the stones.

Serial radionuclide imaging during treatment of patients with diffuse bone metastases from carcinoma of the prostate.

Follow-up studies have been undertaken on patients with carcinoma of the prostate who, prior to treatment, exhibited uniformly increased bone uptake of 99mTclabelled methylene diphosphonate. In general, therapy led to a reduction in the degree of radiopharmaceutical uptake on follow-up. In some cases the radionuclide bone images retained their uniform appearances, whilst in others a patchy uptake developed, more characteristic of metastatic deposits. Radiographically the changes were less pronounced than those seen in the radionuclide studies.

The influence of picture element size on the quality of clinical radionuclide images

The effect of picture element (pixel) size on image quality is investigated. Asked simply to state their preference for clinical images displayed with different pixel sizes, observers preferred those with the smallest pixel. Specific perceptual tasks, however, such as abnormality detection, are found to be insensitive to changes in pixel size up to a limit. Interpolation is found to have no effect on perceptual tasks, but 'random interpolation' produced a more pleasing image than simple linear interpolation.

Automatic alignment of radionuclide images

The variability of the position, dimensions and orientation of a radionuclide image within the field of view of a gamma camera hampers attempts to analyse the image numerically. A method is described for using a set of training images of a particular type, in this case right lateral brain images, to define the likely variations in the position, dimensions and orientation for that type of image and to provide alignment data for a program that automatically aligns new images of the specified type to a standard position, size and orientation. Examples are given of the use of this method on three types of radionuclide image.

RADIOUNUCLIDE IMAGING OF THE NECK IN RHEUMATOID ARTHRITIS

Blind marking was used to assess radionuclide neck images obtained with technetium-99m methylene diphosphonate in 28 patients with rheumatoid arthritis and 12 with cervical degenerative joint disease (spondylosis). Eleven out of the 16 rheumatoid arthritis patients who had neck pain when imaged showed enhanced uptake in the region of the atlantoaxial and temporomandibular joints. In contrast, no patient with cervical spondylosis and only one rheumatoid arthritis patient without neck pain had high uptake in either joint. Changes in uptake in this region on repeat imaging correlated significantly (P less than 0.01) with changes in pain. Patients with rheumatoid arthritis, with or without neck pain, and with cervical spondylosis showed similar patterns of radiological abnormality in the cervical spine. No detailed correlation was detected between radionuclide and radiographic findings. Radionuclide abnormalities were seen in the middle and lower cervical spine in both rheumatoid arthritis and cervical spondylosis. An abnormal radionuclide image of the middle or lower neck is thus of little value except when no degenerative change is present on the radiograph. An abnormal radionuclide image of the upper neck may be a useful indication of inflammation.

A method for measuring mean circumferential fiber shortening rate from gated blood pool scans.

Ejection fraction and ejection rate are easily obtained from gated cardiac images, but no method is available for calculating mean circumferential fiber shortening rate. We assumed that the cube root of left ventricular end-diastolic volume or counts is proportional to the minor axis of the left ventricle at end-diastole or end-systole. Mean circumferential fiber shortening rate is then equal to the [cube root of the end-diastolic volume (count) minus cube root of end-systolic volume (count)] divided by [cube root of end-diastolic volume (count) multiplied by the ejection time]. In 250 contrast ventriculograms, the standard mean circumferential fiber shortening rate (MCFSR) and that derived by the cube root method correlated well (r = 0.94). The mean value of MCFSR (0.85 +/- 0.35) was greater than the cube root value (0.75 +/- 0.35) (P less than 0.001). The regression equation was y = 0.86x + 0.02. Similar correlations were obtained from gated radionuclide images using a semiautomated program (r = 0.93) in 24 subjects or completely automated program (r = 0.85) in 28 patients. The regression equation between MCFSR and that derived from the cube root of counts for the semiautomated program was y = 0.82x + 0.04 and for the automated program was y = 0.84x + 0.004. Similar correlations, slopes, and intercepts were seen using circumferential fractional shortening for angiographic data when correlated with both the semiautomated and automated gated blood pool scan programs. These data indicate that MCFSR and circumferential fractional shortening may be obtained from gated blood pool images using cube root estimates of end-diastolic and end-systolic radii with a high degree of correlation with the standard contrast ventriculographic technique.

The location of urinary calculi using radionuclide imaging.

Summary— A method of in vivolabeling urinary calculi with 99mTc‐methylene diphosphonate is described. This enables a radionuclide image of the stones to be produced and permits their location at operation by means of a small scintillation detector. The degree of uptake of the radiopharmaceutical on renal stones appears to depend on a number of factors, particularly the chemical composition of the stones.

Splenic-gonadal fusion: Identification by radionuclide scanning

Splenic-gonadal fusion is an unusual congenital anomaly resulting from the fusion of the splenic and gonadal anlagen at approximately the sixth week of gestation. A 14-mo-old male presenting with signs and symptoms of testicular torsion underwent scrotal exploration, and ectopic splenic tissue was found adjacent to the left testis. The operative diagnosis of splenic-gonadal fusion prompted abdominal scanning with 99mTc-sulfur colloid. The radionuclide image demonstrated an unusual pattern of activity that was consistent with surgical descriptions of the intraabdominal appearance of this disorder. It is suggested that 99mTc-sulfur colloid scanning may prove to be a useful adjunct in the evaluation of patients with this anomaly.

Localisation of experimental staphylococcal abscesses by 99MTC-technetium-labelled liposomes.

The accumulation of 99mTc-technetium-labelled liposomes in abscesses was studied. Abscesses were produced in the thighs of albino rats by intramuscular injection of Staphylococcus aureus. After 4 days these abscesses were used to determine the localisation of 99mTc-technetium-labelled anionic, cationic and neutral liposomes in the abscess area. This was achieved by radionuclide images produced by a gamma camera and an associated data-processing system. There was a pronounced uptake of 99mTc-technetium-labelled anionic liposomes in the abscess area compared with the corresponding unaffected thigh. Similar uptake was not shown by the 99mTc-technetium-labelled cationic and neutral liposomes. Abscess uptake of anionic liposomes was maximal at or before 30 min after injection and was not enhanced by prior opsonisation with aggregated rat immunoglobulin.