Paul H. Brown

Comparison of biokinetics and biliary imaging parameters of four Tc-99m iminodiacetic acid derivatives in normal subjects.

The biokinetics (blood clearance, urinary excretion, hepatic peak time, uptake, and excretion t-½) and the imaging parameters (the time of appearance of the common bile duct, gallbladder, and duodenum) were determined in 34 normal subjects using Tc-99m diethyl (EIDA), Tc-99m dimethyl (HIDA), Tc-99m paraisopropyl (PIPIDA), and Tc-99m parabutyl (PBIDA) iminodiacetic acid derivatives. The blood and hepatic clearance of the four agents were significantly different (P < 0.05) from each other. The 24-hour urinary excretion of PBIDA was significantly lower (P < 0.05) than the urinary excretion of the other three agents. There was no difference among the four agents in the time of appearance of the gallbladder and duodenum. The time of appearance of the common bile duct was significantly delayed with PBIDA. The maximum intensity of the common bile duct usually occurred between 20 to 40 minutes with all four agents. However, gallbladder intensity continued to increase up to 3 hours. It is concluded that in the presence of normal liver function, all four Tc-99m IDA agents show definite differences in biokinetics but these differences do not have a major effect on biliary imaging parameters. If imaging alone is the primary goal, the selection of any one of the four agents will meet the clinicians need satisfactorily.

Development and validation of a comprehensive new hepatobiliary software. Part II: Segmental liver function.

ObjectiveThis study was undertaken to develop comprehensive new hepatobiliary software to quantify segmental and lobar liver function and to obtain FDA approval. MethodsHepatobiliary software written on JAVA platform and loaded on to a PC accepts 99mTc-HIDA dicom image data transferred from a &ggr; camera. Liver boundary was determined by threshold-based auto edge detection and liver height at right midclavicular (RMCL) line. Geometric mean area of the physiologic right lobe, physiologic left lobe and total liver area were measured. Segmental liver function was determined using the 5th minute frame as the default (100%). ResultsIn 24 control participants, mean (±SD) liver height at RMCL was 14.7±0.12 cm. Geometric mean area of the physiologic right lobe was 116±3 cm2, left lobe 96±4 cm2, and total liver area 212±3 cm2. Right upper lobe (segments 7 and 8) contributed 31±0.7%, right lower lobe (segments 5 and 6) 34±0.6%, left medial (segments 4A and 4B) 24±1%, left lateral (segments 2 and 3) 10±2%, and caudate lobe (segment 1) 1±0.02% of total liver function. In 23 patients, contrast three-dimensional computerized tomographic volume of the right lobe was 1194±419 ml, left lobe 434±221 ml, and total liver volume 1628±490 ml. Right lobe area was120±30 cm2, left lobe (plus caudate) 88±29 cm2 with total liver area of 208±51 cm2. Right upper lobe (segments 7 and 8) contributed 33±10%, right lower lobe (segments 5 and 6) 34±7%, left medial (segments 4A and 4B) 23±6%, left lateral (segments 2 and 3) 9±3%, and caudate lobe (segment 1) 1±0.4% of total liver function. There was good correlation of RMCL height, and area of right lobe and total liver with computerized tomographic liver volume. Correlation of percentage volume with percentage function was excellent. ConclusionNew FDA approved software provides quantitative assessment of segmental, lobar, and total liver size and function from a planar 99mTc-HIDA cholescintigraphy and may enable universal standardization in nuclear hepatology. Quantification may aid surgeons in the determination of the amount of tissue resection during liver surgery.

Changing publication trends in nuclear medicine, 1965-1980.

During a search through the nuclear medicine literature, it was noticed that there was an increase in the number of journals publishing articles related to nuclear medicine as well as a change in the direction of nuclear medicine articles, moving away from morphology alone to a combination at morphology and physiology. We have attempted to document these trends via a survey of nuclear medicine journal literature for the period 1965-1980.

A GAMMA CAMERA METHOD OF MEASURING REGIONAL CEREBRAL BLOOD FLOW (rCBF) BY Xe-133 WASHOUT TECHNIQUE

Previous researchers have utilized the Obrist method for measurement of rCRB using end-tidal, exhaled air counts to correct for recirculation. Choice of the appropriate end-tidal air point is difficult and requires rapid air sampling (0.3 sec) with concomitant poor statistics. A comparison was made between this end-tidal air sampling method and a simpler-to-use average, expiratory air curve (6 sec sampling) in 9 normal volunteer controls, and in 9 patients with carotid artery stenosis or occlusion. The Obrist deconvolution technique was adopted for use on a Picker 4 gamma camera and MDS computer. A high sensitivity collimator insert with square holes measuring 1.7 cm across and 3.8 cm in depth was used. A one minute combination Xenon-133 inhalation and equilibrium period was followed by 10 minutes of washout. A two component exponential was fitted to the deconvoluted brain curves. For the functional images, a MDS rainbow color translation table was used. Two sequences of 9 point spatial smoothing were tested, one with a single smooth before curve generation and another with 2 smooths after. The new method, using 6 second, average expiratory air sampling and a single 9 point spatial smooth before curve generation, demonstrated areas of decreased flow which corresponded to the angiographic findings and clinical findings in each case and demonstrated them equal to or better than the standard method. By the new method, very few abnormal areas were found in the controls, and decreases in the control patients were almost always less than when using the 0.3 sec air sampling time.