Computer assisted interpretation of Tc-99m mercaptoacetyltriglycine diuretic scintigraphy enhances resident performance.

Objective: iRENEX is a software module that incorporates scintigraphic and clinical data to interpret 99m Tc- mercaptoacetyltriglycine (MAG3) diuretic studies and provide reasons for their conclusions. Our objectives were to compare iRENEX interpretations with those of expert physicians, use iRENEX to evaluate resident performance and determine if iRENEX could improve the diagnostic accuracy of experienced residents.

Methods: Baseline and furosemide 99m Tc-MAG3 acquisitions of 50 patients with suspected obstruction (mean age ± SD, 58.

Tc-MAG: Image Wisely.

Purpose To determine if commonly administered doses of technetium 99m (Tc) mertiatide (MAG) in the range of 300-370 MBq (approximately 8-10 mCi) contribute to image interpretation and justify the resulting radiation exposure. Materials and Methods The respective institutional review boards approved this HIPAA-compliant study and waived informed consent. Baseline and furosemide Tc-MAG imaging examinations in 50 patients suspected of having renal obstruction and 48 patients suspected of having renovascular hypertension (RVH) were randomly selected from archived databases and were independently scored by three experienced readers without access to 2-second flow images.

iRENEX: a clinically informed decision support system for the interpretation of ⁹⁹mTc-MAG3 scans to detect renal obstruction.

Purpose: Decision support systems for imaging analysis and interpretation are rapidly being developed and will have an increasing impact on the practice of medicine. RENEX is a renal expert system to assist physicians evaluate suspected obstruction in patients undergoing mercaptoacetyltriglycine (MAG3) renography. RENEX uses quantitative parameters extracted from the dynamic renal scan data using QuantEM™II and heuristic rules in the form of a knowledge base gleaned from experts to determine if a kidney is obstructed; however, RENEX does not have access to and could not consider the clinical information available to diagnosticians interpreting these studies.

Guidance document for structured reporting of diuresis renography.

This Guidance Document for structured reporting of diuresis renography in adults was developed by the International Scientific Committee of Radionuclides in Nephro-urology (ISCORN; http://www.iscorn.org).

Correlation between serum cardiac markers and myocardial infarct size quantified by myocardial perfusion imaging in patients with hypertrophic cardiomyopathy after alcohol septal ablation.

Myocardial infarct (MI) size is a well-established prognostic marker but the association of serum markers with MI size, as measured by myocardial perfusion imaging (MPI), has not been well studied in patients with hypertrophic cardiomyopathy (HC) after alcohol septal ablation (ASA). Creatine kinase (CK), CK-MB, troponin I, and brain natriuretic peptide were measured before and at multiple points after ASA in patients with HC and were correlated with MI size measured by MPI. MPI at rest was performed in 54 patients with HC at a median of 2 days after ASA.

Diagnostic performance of an expert system for interpretation of 99mTc MAG3 scans in suspected renal obstruction.

Unlabelled: The purpose of the study was to compare diuresis renography scan interpretation generated by a renal expert system with the consensus interpretation of 3 expert readers.

Methods: The expert system was evaluated in 95 randomly selected furosemide-augmented patient studies (185 kidneys) obtained for suspected obstruction; there were 55 males and 40 females with a mean age +/- SD of 58.6 +/- 16.

Evaluation of two diuresis renography decision support systems to determine the need for furosemide in patients with suspected obstruction.

Objective: The purpose of this study was to compare the decisions regarding the need for furosemide made by two independent renal decision support systems, RENEX and CAR-TAN, with the need for furosemide determined in clinical practice and by expert reviewers using the baseline plus furosemide protocol.

Subjects And Methods: RENEX and CARTAN are independent decision support systems that reach their conclusions without operator input. RENEX is a knowledge-based system and CARTAN is a statistical decision support system.

Use of classification and regression trees in diuresis renography.

Rationale And Objectives: Decision support systems have the capacity to improve diagnostic performance and reduce physician errors. The purpose of this study was to evaluate the use of classification and regression trees (CART) with bootstrap aggregation as a decision support system in the baseline plus furosemide (F + 20) diuresis renography protocol to determine when obstruction can be excluded without the furosemide acquisition and to identify the key parameters for making this determination.

Materials And Methods: Patients with suspected ureteral obstruction were randomly assigned to a training set (80 patients, 157 kidneys) and a validation set (64 patients, 124 kidneys).

Outcome of patients with adenosine-induced ST-segment depression but with normal perfusion on tomographic imaging.

Most patients with ST depression during adenosine infusion have reversible perfusion defects by single-photon emission computed tomographic (SPECT) perfusion images. Occasionally ST depression is observed in the setting of normal perfusion images. The outcome of such patients is controversial.

RENEX: an expert system for the interpretation of 99mTc-MAG3 scans to detect renal obstruction.

Unlabelled: A renal expert system (RENEX) has been developed to assist physicians detect renal obstruction in patients undergoing pre- and postfurosemide 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) scans. RENEX uses quantitative parameters extracted from the dynamic renal scan data and heuristic rules in the form of a knowledge base (KB) obtained from expert interpreters to conclude whether a kidney is obstructed.

Methods: Normal limits were established for 47 quantitative parameters extracted from the 99mTc-MAG3 scans of 100 potential renal donors.

Retrospective family study of childhood medulloblastoma.

Medulloblastoma is the most common malignant central nervous system tumor of childhood and can occur sporadically or in association with inherited cancer susceptibility syndromes such as the nevoid basal cell carcinoma syndrome (NBCCS). To determine whether an association existed between the risk of developing medulloblastoma and undiagnosed syndromes, we retrospectively reviewed clinical data on 33 patients with medulloblastoma from a single institution and compared them with their unaffected relatives (n = 46). Six patients had tumors showing desmoplastic histology.

CT scout films: don't forget to look!

Background: A lateral scout view of the head is always obtained when performing head computed tomography (CT). It is common knowledge that viewing the lateral scout view may provide additional information. For a variety of reasons, however, a careful review may not be performed routinely.

Fetal MRI evaluation of an intracranial mass: in utero evolution of hemorrhage.

The role of MRI in the evaluation of fetal abnormalities is still under evaluation. We describe a case of an intracranial mass that was initially identified by prenatal ultrasound and was further evaluated by MRI. Ultimately, the findings were most consistent with hematoma secondary to an underlying dural malformation with spontaneous involution.

Report of a child with aortic aneurysm, orofacial clefting, hemangioma, upper sternal defect, and marfanoid features: possible PHACE syndrome.

We report a female patient who had a scalp hemangioma, a cleft uvula, an upper sternal defect, pectus excavatum, arachnodactyly, pes planus, and joint hypermobility. She had rupture of an aortic aneurysm after minor trauma at 11 years of age. At 17 years of age, elective repair of a dilated, ectatic aorta was complicated by cerebral ischemia.

A Bayesian regression model for plasma clearance.

Unlabelled: Nonlinear Bayesian regression permits curve fitting to a group of subjects simultaneously rather than individually. We evaluated this approach for interpreting plasma clearance curves with the goal of reducing curve-fitting failures and dealing objectively with problem datasets that may arise in clinical settings.

Methods: (99m)Tc-Diethylenetriaminepentaacetic acid plasma clearance curves from 79 subjects were analyzed.

Low incidence of abnormal (18)FDG-PET in children with new-onset partial epilepsy: a prospective study.

Objective: Patients with refractory partial epilepsy often exhibit regional hypometabolism. It is unknown whether the metabolic abnormalities are present at seizure onset or develop over time.

Methods: The authors studied 40 children within 1 year of their third unprovoked partial seizure with EEG, MRI, and [(18)F]-fluorodeoxyglucose ((18)FDG)-PET (mean age at seizure onset = 5.

Prediction of renal transplant survival from early postoperative radioisotope studies.

Unlabelled: It has been routine at the University of Alabama Medical Center to obtain a radionuclide renal function study immediately after transplantation (usually within 3 d) that includes estimation of effective renal plasma flow (ERPF) from a single plasma sample in addition to imaging. We present here the correlation between baseline measurements and the 1-y graft survival.

Methods: Two cohort years were reviewed: 1988, when 131I-orthoiodohippurate (OIH) was used; and 1995, when 99mTc-mercaptoacetyltriglycine (MAG3) was used.

Intracranial calcifications in childhood medulloblastoma: relation to nevoid basal cell carcinoma syndrome.

Background And Purpose: Medulloblastoma is one of the most common posterior fossa tumors to occur in children. Our purpose was to document the frequency, location, and time of occurrence of intracranial calcifications in cranial CT studies of children with medulloblastoma.

Methods: We retrospectively reviewed cranial CT studies of 56 patients diagnosed with medulloblastoma from 1983 through 1997 for the presence of intracranial calcifications.

Imaging and clinical evaluation of isolated atresia of the oval window.

Background And Purpose: Congenital causes of hearing loss in children commonly are encountered, and imaging aids in diagnosis as well as presurgical evaluation. Atresia of the oval window not associated with atresia of the external auditory canal (EAC) is a rare cause of congenital hearing loss in children. We present the clinical and imaging findings in children with isolated oval-window atresia.

Effect of arteriovenous difference in measuring renal function by single-injection plasma clearance: role of bolus.

Error estimates for arteriovenous difference were calculated by two models, a lag time model and a compartmental model, using Tc99m-diethylenetriaminepentaacetic acid (DTPA) plasma clearance curves from 40 subjects and Tc99m-MAG3 (mercaptoacetyltriglycine) curves from 18 subjects. It was found that correcting for the effect of the initial bolus largely cancelled the conventional arteriovenous difference, so that the net error was negligible.

Stroke after zoster ophthalmicus in a 12-year-old girl with protein C deficiency.

A 12-year-old girl who had zoster ophthalmicus 10 months earlier presented with hemiparesis and corresponding basal ganglionic infarction related to middle cerebral artery branch thrombosis ipsilateral to the zoster. Hematologic evaluation disclosed protein C deficiency. This represents the first zoster-associated stroke reported in childhood associated with protein C deficiency, with extension of the latency period between zoster and infarction, previously reported to be 6 months.

Reproducibility of single-sample clearance of 99mTc-mercaptoacetyltriglycine and 131I-orthoiodohippurate.

Unlabelled: Recent literature has questioned whether 99mTc-mercaptoacetyltriglycine (MAG3) clearance measurements are reproducible enough for routine clinical monitoring of renal function. For many years, we have routinely followed the renal function of patients with spinal cord injuries using a combination of radionuclide imaging and clearance measurement.

Methods: In this study, we retrospectively review 1626 effective renal plasma flow (ERPF) measurements in 197 patients with paraplegia or quadriplegia performed over a 21-y period, using 131I-orthoiodohippurate (OIH) through 1990 and MAG3 since 1991.