R. H. Bahar

Brucellosis: appearance on skeletal imaging

Brucellosis is an endemic disease in the Middle East. Its incidence in Kuwait has increased during the last 5 years. Bone and joint involvement causes major symptoms and disabilities. Radionuclide bone scans are more sensitive than radiographs in detecting these lesions. The aim of this study is to describe the abnormal patterns detected on bone imaging in acute and chronic brucellosis. Tc-99m MDP bone scans of 56 patients with established diagnosis of brucellosis (19 acute and 37 chronic) were retrospectively analyzed. Bone scans were positive in 8 of 19 patients (42%) with acute brucellosis and in 28 of 37 patients (76%) with chronic brucellosis. Six patterns were observed: involvement of an entire body of one or more vertebrae, especially at the lumbar region (50%); sacroiliitis (41%); focal high uptake at the junction of the upper and lateral margins of the vertebra “Caries sign” (27%); multiple costovertebral joints and costochondral junction involvement (19%); involvement of large joints similar to degenerative osteoarthritis (25%); and focal involvement of long bone (11%).

The hollow skull: a sign of brain death in Tc-99m HM-PAO brain scintigraphy.

The advantage of Tc-99m HM-PAO, a newly introduced compound for brain perfusion imaging, is illustrated in three patients with suspicion of brain death. With Tc-99m HM-PAO, the carotid flow study is not essential, as it is in the Tc-99m pertechnetate carotid angiogram; planar images are equally useful; and there is no need for SPECT images. For the diagnosis of brain death, Tc-99m HMPAO can be injected in the intensive care unit and planar images can be obtained at a later time using a mobile camera or whenever the patient can be moved to the nuclear medicine department.

Left ventricular function of survivors of a first complicated acute myocardial infarction. A prehospital discharge cross-sectional echocardiographic study

To assess the left ventricular function of patients who suffer from post-infarction angina and left ventricular failure in the coronary care unit, 79 consecutive survivors (mean age 48 years) of a first acute myocardial infarction were prospectively studied and followed-up for a mean 18- (10-34) month period. Forty-seven had an uncomplicated infarction, 17 suffered from post-infarction angina and 15 had left ventricular failure. The left ventricular function of these patients prior to discharge from hospital was assessed by cross-sectional echocardiography and radionuclide angiography. Analysis of left ventricular wall motion was performed in all patients using a 11-segment model of the left ventricular. The ejection fraction was determined by echocardiography in 47 patients and by radionuclide angiography in 50. The mean echocardiographic wall motion score of post-infarction angina patients (4.8 +/- 0.8) (+/- SEM) was lower than that of patients with left ventricular failure (9.5 +/- 0.5) (P less than 0.001), but was not different from patients suffering uncomplicated infarctions (4.6 +/- 0.3). The mean echocardiographic ejection fraction was also similar in post-infarction angina (45.3 +/- 4.0; n = 16) and patients with uncomplicated infarction (51.9 +/- 2.7; n = 17), but was lowest in the group of patients with left ventricular failure (35.1 +/- 3.3; n = 14). Similarly, the radionuclide ejection fraction of patients with post-infarction angina (41.4 +/- 3.4; n = 17) and patients with uncomplicated infarction (45.6 +/- 2.7; n = 19) did not differ, but was lower in patients with left ventricular failure (25.9 +/- 2.8; n = 14). The echocardiographic ejection fraction correlated with that obtained by radionuclide angiography in all 46 patients (r = 0.71, P less than 0.001). The wall motion score correlated with the radionuclide ejection fraction in all 50 patients (r = -0.73, P less than 0.001) and with the echocardiographic ejection fraction in 47 patients (r = -0.55, P less than 0.001). During follow-up, 3 (18%) patients suffering post-infarction angina and 2 (13%) with left ventricular failure died. New infarction was seen in 2 (12%) and 1 (7%) patients in these groups, respectively. We conclude that the left ventricular function of patients who suffer from post-infarction angina in the coronary care unit is good, but is impaired in those with even transient left ventricular failure. Echocardiographic assessment of cardiac function prior to hospital discharge was highly successful and may be performed in all such patients.

Quantitative analysis of cardiac function: comparison of electro-cardiogram dual gated single photon emission tomography, planar radionuclide ventriculogram and contrast ventriculography in the determination of LV volume and ejection fraction.

A dual gated tomography (DGT) program for end systolic and end diastolic acquisition and subsequent processing for calculation of LVEF, end diastolic and end systolic volumes (EDV, ESV) has been evaluated in 20 healthy volunteers (25 years–40 years) and 45 patients (25 years–60 years): 20 with ischaemic heart disease and 25 with valvular heart disease (VHD). All had biplane multigated blood pool (MUGA) studies in the 40° LAO projection using in vivo 99mTc- RBCs, immediately followed by DGT. The results in the patients group were correlated with contrast ventriculography (CV). In the volunteer group, the normal values for LVEF, EDV and ESV measured with DGT were found to be 63%±10%, 91 ml±6 ml and 30 ml±6 ml and r value for the LVEF=0.91 compared with MUGA. In the IHD group, r values compared with CV were 0.915 and 0.97 for the EDV and ESV and 0.934 for the LVEF. Compared with the MUGA, the r value for LVEF was 0.883. In the VHD group, r values were 0.98 for both the EDV and ESV and 0.948 for the LVEF (P<0.002) compared with CV and 0.789 for the LVEF compared with the MUGA. We feel that DGT is an accurate and reproducible technique for LV function measurements.

“Pulmonary tongue” a right ventricle phase abnormality in muga studies in patients with pulmonary hypertention

Pulmonary hypertension (PH) produces strain followed by hypertrophy and later dilatation of the right ventricle (RV) and pulmonary artery. The signs and symptoms are nonspecific. There is a need for a noninvasive sensitive way to diagnose PH. The purpose of this study is to evaluate phase abnormalities in radionuclide MUGA studies of patients with referred diagnosis of PH. In a retrospective analysis of 44 patients who had a radionuclide multigated study (MUGA) and contrast ventriculography (CV), 19 had high mean pulmonary pressure (over 20 mmHg) and a high pulmonary vascular resistance index (over 2.0). In 15 patients, a delayed phase segment in the RV corresponding to the pulmonary infundibulum and pulmonary conus was noted “The Pulmonary Tongue” sign (PT), 12 had PH (True positive) and 3 did not (false positive) on CV. No PT was seen in the remaining 29 patients, only 7 of them had PH (False negative). The sensitivity, specificity and accuracy of the PT sign in detecting PH was 80%, 72% and 77% respectively. The number of patients was too small to calculate the correlation of the grade of PT with the severity of PH. We conclude that “The Pulmonary Tongue” sign on a MUGA study is clinically useful in detecting PH.

A New Experimental Model for Partial Ureteric Obstruction in Sheep

This study aimed to develop a new experimental model of partial ureteric obstruction in sheep. Graded obstruction of the ureter using various sized catheters (Fr 3–8) for variable durations up to 6 weeks was performed in 19 sheep. The kidneys were studied by radionuclide diuretic renography for up to 21 weeks and had histopathological examination at the end of the experiment. Catheters of Fr 3 or Fr 5 should be used to block the ureter for a minimum of three weeks to produce sufficient functional and pathological changes to be studied. The advantages and disadvantages of this model are discussed.

Experimental complete ureteric occlusion in sheep : radionuclide renography and histopathologic findings

Complete ureteric occlusion produces various pathophysiological changes that can be monitored externally by technetium 99m diethylenetriamine penta-acetic acid (99mTc-DTPA) diuretic renography (RDR). Being a dynamic imaging study, it reflects the function of the kidneys and the urodynamics of the urinary tract. The aim of this study was to correlate the changes in parameters of RDR with the histological changes before and after the release of complete ureteric occlusion. In 9 sheep, RDR studies were performed serially after various periods of complete ureteric occlusion (up to 7 weeks) and after release of the occlusion (up to 5 weeks). The histological changes were correlated with changes in RDR. The progressive decrease in renal flow seen on renal images and flow time-activity curves (TACs) was explained by the development of endarteritis and thrombosis of small renal arteries. The progressive decrease in the renal uptake as indicated by the percentage renal uptake and the extraction slope of TAC is related to the progressive damage to the renal parenchyma, initially affecting the collecting ducts and tubules, with increasing interstitial fibrosis in the later stages. Obstruction for 3 weeks or less was associated with moderate damage to the parenchyma from which recovery was possible. Obstruction for 7 weeks was associated with marked damage without chance of recovery. The RDR is a non-invasive technique that can be used to monitor kidney damage after various periods of complete ureteric occlusion and to predict the outcome of surgery before the release of occlusion.

Detection of infection of a cardiac xenograft by gallium-67 scan

We describe a case complicated by infection of a xenograft conduit with subsequent septic emboli to the left kidney in the setting of pulmonary atresia with ventricular septal defect which was positively imaged using radioactive gallium-67. Confirmation was provided by cross-sectional echocardiography and positive blood culture. The patient improved with antibiotic therapy.

Acute intrahepatic biliary obstruction caused by hydatid cysts. Correlation between various imaging techniques.

An 18-year-old male was evaluated for recurrent attacks of right abdominal pain and intermittent jaundice caused by hydatid cysts of the liver. The case illustrates the value of dynamic functional information provided by Tc-99m-HIDA imaging over noninvasive modalities that demonstrate structural changes, such as ultrasound, computed tomography, and tin colloid liver imaging.

Upper gastrointestinal bleeding from the biliary tract (hematobilia). Detection by technetium-99m DTPA.

A case of hematobilia causing upper gastrointestinal bleeding is demonstrated by Tc-99m DTPA. The advantages of Tc-99m DTPA over Tc-99m sulfur colloid and RBCs are discussed.