Radiological and radionuclide investigation of malignant otitis externa.

This study looks at case series of malignant otitis externa, outlines detailed structural (radiological) and functional (radionuclide) investigations, and discusses their utility in the initial diagnosis, patient management and follow up of this condition. Patients were investigated by computerized tomography (CT), magnetic resonance imaging (MRI), two-phase planar and single-photon emission tomography (SPECT), technetium-99m methylenediphosphonate bone scans, gallium-67 planar and SPECT scans, and indium-111 or technetium-99m labelled WBC planar and SPECT scintigraphy. We discuss example case reports with the various radiological and scintigraphic findings and outline a protocol for rational investigation. It is concluded that CT and/or MRI should be supported by routine SPECT bone imaging for initial diagnosis of malignant otitis externa. Routine SPECT bone imaging further supplemented by gallium scintigraphy should be the investigation of choice in the follow up of these cases for assessing response to treatment and disease recurrence.

Captopril renal scintigraphy in patients with hypertension and chronic renal failure.

UNLABELLED: The aim of this prospective study was to determine the ability of the captopril renogram to reveal the presence of angiotensin II-dependent renovascular disorder in hypertensive patients with chronic renal failure and to assess the possibility of predicting beneficial effect of angiotensin-converting enzyme (ACE) inhibitors on renal function. METHODS: Forty-one patients were evaluated. Baseline renal scintigraphy was performed with 80 MBq of 99mTc-mercaptoacetyltriglycine (MAG3) injected intravenously. Scintigraphy was repeated within a week with 25 mg of oral captopril given 60 min prior to the test. Using the measurements outlined by the Working Party on Diagnostic Criteria of Renovascular Hypertension with Captopril Renography, the patients were categorized into high (7 patients), indeterminate (19 patients) and low (15 patients) probability for renal artery stenosis (RAS). RESULTS: In five of the seven patients with high probability, the presence of RAS was confirmed angiographically and corrective surgical procedure performed in two. In patients with GFR of 10 ml/min/1.73 m2 and/or split renal function of 10% or less, all qualitative and semiquantitative scintigraphic parameters were nonspecific. Mean parenchymal transit time of tracer was a useful parameter to predict the beneficial effect of ACE inhibition therapy in 23 patients (14 low and 9 indeterminate probability of RAS). CONCLUSION: In hypertensive patients with renal failure, captopril renal scintigraphy can be utilized to identify the presence of angiotensin II-dependent renal dysfunction and possibly help to predict the beneficial effect of ACE inhibitor therapy.

The effect of intracavernosal haemodilution on the radionuclide quantification of penile vascular changes during pharmacologically induced penile erections.

Radionuclide phallography was performed using 99Tcm-labelled red blood cells in conjunction with pharmacologically induced penile erections. The radioactivity content of aliquots of systemic venous blood taken from the antecubital vein was compared with aliquots of blood withdrawn from the penile cavernosa 20 min after an intracavernosal injection of 10 micrograms prostaglandin E1. The cavernosal samples showed significantly lower counts per unit of blood compared to the systemic venous blood indicating a comparatively lower concentration of tagged red blood cells. On haematological analysis, a significant difference in the haematocrit of the two samples was also established. The fall in the cavernosal haematocrit was found to result from dilution of the cavernosal blood pool by the injected volume of the drug since larger volumes of injection produced a greater fall in the haematocrit. Restriction of the cavernosal venous outflow in response to the injection of the vasoactive drug causes sequestration of the diluted blood in the cavernosal compartment. This factor might affect the quantification of penile blood volume using radiotracer methods.

A pilot study of flaccid penile blood flow patterns in normal subjects and patients with erectile dysfunction.

Dynamic penile scintigraphy was performed using 99Tcm-labelled autologous erythrocytes in five normally potent volunteers and 22 patients with erectile dysfunction including 11 patients with psychogenic and 11 patients with vasculogenic impotence (four arteriogenic, three venogenic, three arteriogenic and venogenic, one arteriogenic and neurogenic). Penile radioactivity changes in the flaccid state were monitored by a gamma camera for 60 min after injection of the radionuclide. The penile time-activity curves of the normal controls characteristically showed secondary pulses of increased activity of variable amplitude, duration and frequency, consistent with phasic increase in penile blood pool. This normal rhythmic pattern was impaired in patients with penile arterial insufficiency whereas a blunted pattern was seen in most patients with functional impotence as well as in patients with nonarteriogenic organic impotence with a psychological overlay. This study provides new insights into the flaccid penile circulatory physiology, which may contribute to our understanding of the pathophysiology of erectile dysfunction. In arteriogenic subjects, the impaired response may be attributable to an inadequacy of penile arterial inflow as well as secondarily due to the resultant sinusoidal dysfunction subsequent to penile ultrastructural damage due to an altered nutritive environment. Increased adrenergic activity in patients with psychogenic impotence may be responsible for the observed deviation from the normal pattern.

The pyramidal lobe: a scintigraphic assessment.

The thyroid scintigraphs of 207 patients were examined with a view to investigate the anatomical origin of the pyramidal lobe (PL) and in order to determine the incidence of its scintigraphic detection. The PL was visualized in 41% of the cases studied with a greater incidence among the females as compared to the males. It was established that the likelihood of the PL arising from the isthmus of the thyroid or its lobes was about the same. Further, it was observed that the isthmal PL was usually located in the mid-line rather than laterally, in which case it was more often deviated to the left than to the right. The scintigraphic visualization of the PL was seen to increase with the size of the gland but in large goitres it was difficult to detect. It evolves that although at times, there might be a discrepancy between the apparent and the actual location of the PL due to the presence of overlying tissue, in a majority of cases, the scintigraphic appearances do in fact reflect the true picture.

Clinical outcomes of patients with suspected pulmonary embolism using 99Tcm-Technegas as a ventilatory agent for lung scanning.

Clinical outcome analysis was carried out in 175 of 206 consecutive patients referred for a lung scan with clinical suspicion of pulmonary embolism (PE). The follow-up time period ranged from 4 to 18 months. High-quality ventilation images corresponding to the six standard perfusion images were obtained using Technegas as a ventilatory agent. Lung scan reports showed that 22% of the patients had a high, 14% indeterminate, 18% low and 9% very low probability for PE and 37% were normal lung scans. These reports usually supported the referring clinicians' provisional diagnosis and were confirmed by the clinical outcome analysis of these patients giving an apparent sensitivity for the lung scan of 96% and specificity 93%. A strategy for lung scanning in PE is proposed.

Quantitation of pharmacologically-induced penile erections: the value of radionuclide phallography in the objective evaluation of erectile haemodynamics.

This study combines the pharmacologically-induced penile erection (PIPE) technique with radionuclide phallography (RNP) for the non-invasive study of penile haemodynamic changes during erection. Penile erections produced by the intracavernosal injections of two different vasoactive drugs, prostaglandin E1 (PGE1) and papaverine HCl (PPV) were assessed by quantitation of the dynamic RNP and parameters of erection were defined and compared. PGE1 intracavernosal injections were seen to elicit a better erectile response than PPV. Dynamic radionuclide phallography was performed using 99Tcm-labelled autologous RBCs in five normally potent volunteers, sixteen patients with psychogenic impotence, seven patients with vasculogenic impotence (three arteriogenic, four venous leakage) and one patient with neurogenic impotence. Physical parameters of erection including the penile length and circumference changes during erection and the erectile angle were compared with the indices of penile blood flow and volume derived through quantitation of the RNP. There was a close correlation between the penogram index (an index of penile blood volume) and penile circumference increase during erection (r = 0.77, p less than 10(-6). The erectile angle, a measure of penile rigidity, correlated strongly (r = 0.82, p less than 10(-6) with the flow index, a measure of penile blood volume. Patterns specific to various categories of impotence were observed and these aided in the diagnosis, especially in equivocal cases with a suboptimal clinical response to the intracavernosal injection. Quantitative RNP offers a non-invasive method which allows direct objective assessment of the erectile response providing several quantitative parameters for analysis.

The role of the radioisotope phallogram in the investigation of vasculogenic impotence.

Patients complaining of impotence were investigated through a multi-disciplinary approach to define the factors involved. Radioisotope phallography was performed on all the patients using 99Tcm-labelled red blood cells (RBCs) and dynamic records of the variation in activity over the penis were obtained. During the course of the study an intravenous injection of a vasodilator (isoxsuprine HCl) was administered. An analysis of the data provided quantitative parameters for measuring the changes in penile blood flow and penile blood volume in response to the vasodilator injection. The results indicate that the radioisotope phallogram is useful both in the diagnosis of vasculogenic impotence and in indicating the method of treatment.

Predictive value of captopril transit renography in essential hypertension and diabetic nephropathy.

Captopril renography was utilized to assess the presence of angiotensin II dependent renovascular dysfunction in (1) 28 patients with mild to moderate essential hypertension (EH) with unimpaired renal function, and (2) 25 hypertensive patients with diabetic nephropathy (HDN). These studies were classified according to the diagnostic criteria outlined by the Working Party on Diagnostic Criteria of Renovascular Hypertension with Captopril Renography and the mean parenchymal transit time (MPTT) was used as an index for detecting the presence of angiotensin II dependent renal haemodynamic change. Patients with EH showed non-significant or non-specific alterations in the MPTT. Four patients in the HDN group showed a significant prolongation of MPTT in the presence of renin-angiotensin-aldosterone activation due to renal artery stenosis, and the other patients in this group showed a significant decrease in MPTT after captopril, consistent with increased blood flow and improved tubular transport function in the presence of microangiopathy only. We conclude that addition of MPTT to the standard diagnostic criteria of captopril renography may be helpful in predicting the beneficial or detrimental impact of angiotensin II inhibition treatment in HDN and in limiting the test protocol in EH to one post-captopril study.

Isotope phallogram: preliminary communication.

The isotope phallogram is an investigation which uses radioisotope-labelled red cells in the imaging of penile arterial blood flow. In a preliminary series of 12 impotent patients undergoing both internal iliac arteriography and isotope phallography, the penogram index described by Fannous et al. (1982) has been modified to derive an accurate indicator of vascular disease.

Intracavernosal injection of pharmacological agents in the diagnosis and treatment of impotence.

This study details our initial experience with pharmacologically induced penile erections in the diagnosis and therapy of patients with impotence. Intracavernosal injections of papaverine were performed in 5 normal volunteers, 5 patients with psychogenic impotence and 2 patients with penile venous incompetence. The patients were first investigated extensively to determine the etiological basis for their erectile dysfunction. It was observed that the patients with psychogenic impotence and the normal volunteers showed a good response whereas the patients with venous incompetence failed to achieve erection in response to intracavernosal injection. A new drug, Prostaglandin E1 was also tried for the first time for comparison. It appears that this drug has potential advantages over the currently used agent papaverine for the production of pharmacological erections.

Patterns in 51chromium red cell survival and sequestration studies.

Patients with haemolytic anaemias of different etiologies were investigated using the 51Cr red cell survival and surface counting technique. The study provided definitive information regarding the presence of a haemolytic process and was found useful in the estimation of the rate as well as in the demonstration of the principal site of red cell destruction. The study also proved valuable in predicting the response to splenectomy.