Mike Georgiou - Academia.edu (original) (raw)
Papers by Mike Georgiou
99m Tc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acut... more 99m Tc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acute pyelonephritis (APN), especially in children with urinary tract infection (UTI). Diuretic 99m Tc-mercaptoacetyltriglycine (MAG3) dynamic scintirenography has been applied in the evaluation of kidney function and structure, frequently to exclude obstruction. However, in children and adults with a clinical picture of APN, diuretic MAG3 scintigraphy with zero time injection of furosemide (MAG3-F 0 ) was observed to display focal parenchymal abnormalities; regional dysfunction (focal parenchymal decrease in early uptake; slow filling in and prolonged late retention of activity); or, less frequently, fixed defects. This observation was further studied both retrospectively and prospectively, and its sensitivity and specificity for APN were compared with those of dimercaptosuccinic acid (DMSA). Methods: In the retrospective study, for 36 children with UTI and regional parenchymal findings on MAG3-F 0 , data were reviewed, analyzed, and compared with the results of concurrent DMSA studies. In the prospective study, for 57 children with clinical and laboratory findings suggestive of APN, the 2 radiopharmaceuticals were used for imaging sequentially and the results of the 2 studies were compared. The criteria for abnormal findings compatible with the diagnosis of APN were, for MAG3-F 0 , regional parenchymal dysfunction and fixed focal defects and, for DMSA, focal defects without parenchymal loss. Results: In all groups of patients, most abnormal MAG3-F 0 studies (80%) showed regional parenchymal dysfunction, but in some (20%) a fixed defect was found. Compared with DMSA and when both regional dysfunction and focal defects were considered, MAG3-F 0 was as sensitive as DMSA. Some patients had only MAG3-F 0 abnormalities, suggesting a slightly lower specificity for MAG3-F 0 compared with DMSA (86%); this finding needs further study, because it also raises questions about the sensitivity of DMSA, considering that only a small percentage of patients with clinically suggestive findings had abnormal study findings. In most patients with fixed defects on both DMSA and MAG3-F 0 , follow-up studies showed no resolution, suggesting that a fixed defect on MAG3-F 0 may indicate either more severe APN or preexistent scars and that regional dysfunction may be a sign more specific for APN and prognostic of potential recovery. In addition, a pattern more specific for a scar-a fixed defect with a dilated regional calyx-was seen on follow-up MAG3-F 0 . Conclusion: A fast (25-min) planar dynamic MAG3-F 0 study was found to be as sensitive at depicting focal parenchymal abnormalities in APN as was the 3-to 4-h DMSA routine procedure. The sensitivity and specificity of both studies need further evaluation.
In an effort to improve patient care while considering cost-effectiveness, we developed a Picture... more In an effort to improve patient care while considering cost-effectiveness, we developed a Picture Archiving and Communication System (PACS), which combines imaging cameras, computers and other peripheral equipment from multiple nuclear medicine vectors. The PACS provides fully-digital clinical operation which includes acquisition and automatic organization of patient data, distribution of the data to all networked units inside the department and other remote locations, digital analysis and quantitation of images, digital diagnostic reading of image studies and permanent data archival with the ability for fast retrieval. The PACS enabled us to significantly reduce the amount of film used, and we are currently proceeding with implementing a film-less laboratory. Hard copies are produced on paper or transparent sheets for non-digitally connected parts of the hospital. The PACS provides full-digital operation which is faster, more reliable, better organized and managed, and overall more efficient than a conventional film-based operation. In this paper, the integration of the various PACS components from multiple vendors is reviewed, and the impact of PACS, with its advantages and limitations on our clinical operation is analyzed.
Pediatric Nephrology, 1999
Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish t... more Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish the diagnosis and plan treatment of renovascular hypertension (RVH) in 57 hypertensive pediatric patients, 33 infants and 24 children older than 1 year. In 16 of 33 hypertensive infants, ACE inhibition scintirenography established the diagnosis of RVH from renal ischemia (due to aortic or renal arterial thrombi). Two scintigraphic criteria were used for the diagnosis of RVH: criterion I, ischemic and damaged kidney (a non-functioning kidney on or off ACE inhibition) and criterion II, ischemic but not damaged kidney (ACE inhibition induced deterioration of function of the kidney). When criterion I was present and the contralateral kidney was normal, ACE inhibitors could be used for treatment of hypertension without deterioration of renal function; kidneys satisfying criterion I eventually involuted or manifested growth arrest and frequently caused persistent RVH, even after resolution of the thrombus, requiring nephrectomy. When criterion II was present bilaterally, or it was associated with criterion I contralaterally, the use of antihypertensive drugs other than ACE inhibitors was necessary in order to prevent renal insufficiency or failure from ACE inhibitors. However, kidneys with criterion II showed normal growth and, following retraction or dissolution of the aortic thrombus, hypertension resolved. In 2 of 24 hypertensive children older than 1 year, the test was diagnostic of branch renal artery stenosis; RVH was cured by selective angioplasty. ACE inhibition scintirenography is useful in the evaluation and planning of treatment in children with hypertension and may predict the outcome of therapy and ultimate renal function.
99m Tc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acut... more 99m Tc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acute pyelonephritis (APN), especially in children with urinary tract infection (UTI). Diuretic 99m Tc-mercaptoacetyltriglycine (MAG3) dynamic scintirenography has been applied in the evaluation of kidney function and structure, frequently to exclude obstruction. However, in children and adults with a clinical picture of APN, diuretic MAG3 scintigraphy with zero time injection of furosemide (MAG3-F 0 ) was observed to display focal parenchymal abnormalities; regional dysfunction (focal parenchymal decrease in early uptake; slow filling in and prolonged late retention of activity); or, less frequently, fixed defects. This observation was further studied both retrospectively and prospectively, and its sensitivity and specificity for APN were compared with those of dimercaptosuccinic acid (DMSA). Methods: In the retrospective study, for 36 children with UTI and regional parenchymal findings on MAG3-F 0 , data were reviewed, analyzed, and compared with the results of concurrent DMSA studies. In the prospective study, for 57 children with clinical and laboratory findings suggestive of APN, the 2 radiopharmaceuticals were used for imaging sequentially and the results of the 2 studies were compared. The criteria for abnormal findings compatible with the diagnosis of APN were, for MAG3-F 0 , regional parenchymal dysfunction and fixed focal defects and, for DMSA, focal defects without parenchymal loss. Results: In all groups of patients, most abnormal MAG3-F 0 studies (80%) showed regional parenchymal dysfunction, but in some (20%) a fixed defect was found. Compared with DMSA and when both regional dysfunction and focal defects were considered, MAG3-F 0 was as sensitive as DMSA. Some patients had only MAG3-F 0 abnormalities, suggesting a slightly lower specificity for MAG3-F 0 compared with DMSA (86%); this finding needs further study, because it also raises questions about the sensitivity of DMSA, considering that only a small percentage of patients with clinically suggestive findings had abnormal study findings. In most patients with fixed defects on both DMSA and MAG3-F 0 , follow-up studies showed no resolution, suggesting that a fixed defect on MAG3-F 0 may indicate either more severe APN or preexistent scars and that regional dysfunction may be a sign more specific for APN and prognostic of potential recovery. In addition, a pattern more specific for a scar-a fixed defect with a dilated regional calyx-was seen on follow-up MAG3-F 0 . Conclusion: A fast (25-min) planar dynamic MAG3-F 0 study was found to be as sensitive at depicting focal parenchymal abnormalities in APN as was the 3-to 4-h DMSA routine procedure. The sensitivity and specificity of both studies need further evaluation.
In an effort to improve patient care while considering cost-effectiveness, we developed a Picture... more In an effort to improve patient care while considering cost-effectiveness, we developed a Picture Archiving and Communication System (PACS), which combines imaging cameras, computers and other peripheral equipment from multiple nuclear medicine vectors. The PACS provides fully-digital clinical operation which includes acquisition and automatic organization of patient data, distribution of the data to all networked units inside the department and other remote locations, digital analysis and quantitation of images, digital diagnostic reading of image studies and permanent data archival with the ability for fast retrieval. The PACS enabled us to significantly reduce the amount of film used, and we are currently proceeding with implementing a film-less laboratory. Hard copies are produced on paper or transparent sheets for non-digitally connected parts of the hospital. The PACS provides full-digital operation which is faster, more reliable, better organized and managed, and overall more efficient than a conventional film-based operation. In this paper, the integration of the various PACS components from multiple vendors is reviewed, and the impact of PACS, with its advantages and limitations on our clinical operation is analyzed.
Pediatric Nephrology, 1999
Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish t... more Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish the diagnosis and plan treatment of renovascular hypertension (RVH) in 57 hypertensive pediatric patients, 33 infants and 24 children older than 1 year. In 16 of 33 hypertensive infants, ACE inhibition scintirenography established the diagnosis of RVH from renal ischemia (due to aortic or renal arterial thrombi). Two scintigraphic criteria were used for the diagnosis of RVH: criterion I, ischemic and damaged kidney (a non-functioning kidney on or off ACE inhibition) and criterion II, ischemic but not damaged kidney (ACE inhibition induced deterioration of function of the kidney). When criterion I was present and the contralateral kidney was normal, ACE inhibitors could be used for treatment of hypertension without deterioration of renal function; kidneys satisfying criterion I eventually involuted or manifested growth arrest and frequently caused persistent RVH, even after resolution of the thrombus, requiring nephrectomy. When criterion II was present bilaterally, or it was associated with criterion I contralaterally, the use of antihypertensive drugs other than ACE inhibitors was necessary in order to prevent renal insufficiency or failure from ACE inhibitors. However, kidneys with criterion II showed normal growth and, following retraction or dissolution of the aortic thrombus, hypertension resolved. In 2 of 24 hypertensive children older than 1 year, the test was diagnostic of branch renal artery stenosis; RVH was cured by selective angioplasty. ACE inhibition scintirenography is useful in the evaluation and planning of treatment in children with hypertension and may predict the outcome of therapy and ultimate renal function.