George V. Taplin

Lung Imaging with radioaerosols for the assessment of airway disease

Aerosol inhalation lung scans offer distinct advantages in the evaluation of airways and the qualitative distribution of ventilation. The sensitivity in detecting mild obstructive disease is similar to that of xenon washout and both probably surpass standard pulmonary function tests that measure total rather than regional ventilation. Although imaging studies using krypton gas are ideal for assessment of rapidly ventilated space, kryptons short half-life precludes its usefulness for demonstrating air trapping. Neither 133Xe nor 81mKr gas demonstrates sites of airway abnormality as aerosol does. Aerosols are ideal for the general nuclear medicine practice in community hospitals because of their convenience, cost effectiveness, and information yield. Current technique using same-day multiple-view aerosol scans after a preliminary perfusion scan, makes use of the most logical diagnostic scheme in the vast majority of patients with chest complaints, since a normal perfusion scan often eliminates the need for a ventilation scan.

A DUAL LUNG-SCANNING TECHNIC FOR EVALUATION OF PULMONARY FUNCTION.

The recent development of lung scanning with 5–50 μ, size aggregates of human serum albumin I31 has demonstrated the feasibility of scanning methods in evaluating pulmonary function (1–4). Injected intravenously, these particles are trapped temporarily in the pulmonary arteriolar-capillary bed with high efficiency on the first pass, and the subsequent scan image gives a semiquantitative estimate of pulmonary arterial blood flow distribution (5–7). Conceivably, information concerning airway patency could be obtained by scanning after inhalation of radioaerosols if a sufficient fraction were deposited uniformly throughout the lower respiratory tract and retained for a few hours. This preliminary report describes an inhalation technic which, combined with the intravenous method, provides a dual scanning procedure for the evaluation of regional pulmonary arterial blood flow and bronchial patency. Method Animal Studies: Mongrel dogs weighing from 7 to 19 kg are anesthetized with pentobarbital and intubated wit...

Pulmonary Perfusion Changes After Experimental Unilateral Bronchial Occlusion and Their Clinical Implications

Abstract The authors scanned 15 mongrels—9 normal and 6 with unilateral lung reimplants—to see the effect of unilateral bronchial occlusion on pulmonary arterial perfusion. Pulmonary arterial perfusion decreased promptly following airway occlusion in the intact as well as in the reimplanted denervated lungs and reached a minimum level in ten to fifteen minutes. Perfusion changes seem to occur as a local reflex. For accuracy in interpretation of perfusion lung scans, it is important to recognize that obstructive airway disorders associated with localized ventilatory impairment can cause regional pulmonary ischemia and simulate the scans of acute pulmonary embolism.

Improved Radioaerosol Administration System for Routine Inhalation Lung Imaging

An improved radioaerosol administration system has been developed to reduce the number of droplets larger than 2.0 micron in diameter which have caused abnormal hyperdeposition of inhaled aerosols in the large airways. The new system has achieved this goal by interposing a reservoir-setting bag in the aerosol delivery line between the nebulizer and the patient. The components are inexpensive, commercially available and easily assembled in any nuclear medicine service.

Unilateral Pulmonary Artery Agenesis, Stenosis, and Hypoplasia1

Two patients with agenesis, one with stenosis, and one with hypoplasia of the unilateral pulmonary artery were studied by three radioisotope lung imaging procedures. In pulmonary artery agenesis, lack of perfusion with homogeneous ventilation was seen in the affected lung. In pulmonary artery stenosis, perfusion was greatly diminished but ventilation was normal in the affected lung. In pulmonary artery hypoplasia, perfusion and ventilation were diminished and there were scan signs of severe airway obstruction on the affected side. By placing the affected lung in the dependent position, perfusion to the involved lung was increased in stenosis and hypoplasia but was unaltered in agenesis.

Experimental unilateral pulmonary artery occlusion. Acute and chronic effects on relative inhalation and perfusion.

Inhalation and perfusion were studied serially by radionuclide imaging in 15 dogs after unilateral or lobar pulmonary artery occlusion. Relatively decreased inhalation with bronchoconstriction occurred transiently in the ischemic lung immediately following pulmonary artery occlusion but disappeared in several hours. Inhalation of 8% carbon dioxide improved the inhalation, but bronchoconstriction occasionally persisted. After four to six hours, normal inhalation without bronchoconstriction was observed unless complicating pathology developed. Inhalation in absence of perfusion indicates vascular occlusive disease.

Radionuclide Procedures in Predicting Early Renal Transplant Rejection

Results of standard methods were compared with those of several radionuclide procedures as indicators of kidney function and as predictors of early rejection phenomenon in 42 transplant recipients. The bladder/kidney(B/K) scan ratio became positive one to two days prior to the onset of clinical signs in 12 of 14 cases in which rejection occurred during the first two weeks. Renogram indices and hippurate blood clearance values became positive prior to rejection in 5 and 4 of the 14 cases respectively. Results indicate that the B/K scan ratio is more sensitive to impending transplant rejection than blood chemistry or urine output data.

The Radiorenocystogram in Chronic Pyelonephritis

The Hippuran-I131 renocystogram is a reliable external method for detecting functional differences between kidneys (1). Chronic pyelonephritis is especially suitable for investigation with this procedure because it characteristically causes more tissue damage and functional suppression of one kidney than the other (2, 3). While a group of pyelonephritic patients was being studied with serial renocystograms to determine if functional disturbances could be improved by specific treatment, the following observations were made. First, renogram abnormalities associated with this disease are: reduction in the slopes of the tubular segments, delayed onset of excretion, and excretion segments which descend from peak levels at disproportionately slow rates. Second, differences between left and right renal tracings may be accentuated if fluids are restricted eight to twelve hours before the test, whereas they are usually minimized and occasionally concealed if the patient is well hydrated. Third, these aberrations i...

Radioisotope renography in renovascular hypertension.

The radioisotope renogram is especially useful for screening large numbers of hypertensive patients in whom renovascular disease is suspected. An equally valuable application is the detection of ureteral obstruction. It also aids interpretation of pyelograms and renal arteriograms and may be used in their place for following response to treatment.

Respiration of gamma irradiated Brucella abortus and Mycobacterium tuberculosis.

Summary Lyophilized Br. abortus 19 and M. tuberculosis H37RV were exposed to various doses of gamma irradiation from a cobalt-60 source and tested for oxygen uptake on suitable substrates. Cells exposed from 750,000 to 800,000 r failed to grow on appropriate culture media, yet continue to respire at a rate from 40% to 50% of that of the non-irradiated cells.