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P J Mergo

Publications and source records attributed to P J Mergo.

At least 19 recordsLinked to original sources
PubMed2000

A simple method for obtaining original data from published graphs and plots.

OBJECTIVE: To describe a method for deriving original data values from scanned images of graphs and scatterplots published in the medical literature. CONCLUSION: The procedure is simple, reproducible, and relatively error free (when performed carefully). This method is useful in converting published graphic material into numeric data for various uses when the original data are unavailable directly from the authors.

Data Interpretation, Statistical↗
PubMed2000

Characterization of focal hepatic lesions with ferumoxides-enhanced T2-weighted MR imaging.

OBJECTIVE: The purpose of this study was to evaluate whether ferumoxides-enhanced MR imaging of focal hepatic lesions provides distinctive signal intensity and lesion-to-liver contrast changes for benign and malignant lesions, helping to further characterize and differentiate these lesions. MATERIALS AND METHODS: Data analysis was performed on 70 patients, with previously identified focal hepatic lesions, who underwent MR imaging of the liver before and after IV administration of ferumoxides (10 micromol Fe/kg). Lesions analyzed with pathologically proven diagnoses included metastases (n = 40), hepatocellular carcinoma (n = 11), cholangiocarcinoma (n = 6), hemangioma (n = 4), focal nodular hyperplasia (n = 6), and hepatocellular adenoma (n = 3). Response variables measured and statistically compared included the percentage of signal-intensity change and lesion-to-liver contrast. RESULTS: Focal nodular hyperplasia showed significant signal intensity loss on ferumoxides-enhanced T2-weighted images (mean, -43%+/-6.7%, p < 0.01). All other lesion groups showed no statistically significant change in signal intensity on ferumoxides-enhanced T2-weighted images, although signal intensity loss was seen in some individual hepatocellular adenomas (mean, -6.6%+/-24.0%) and hepatocellular carcinomas (mean, -3.3%+/-10.3%). All lesions, with the exception of hepatocellular carcinoma, had a marked increase in lesion-to-liver contrast on ferumoxides-enhanced T2-weighted images, which was statistically significant for metastases and hemangioma (p < 0.02). CONCLUSION: Focal nodular hyperplasia shows significant decrease in signal intensity on ferumoxides-enhanced T2-weighted images, which may aid in the differentiation of focal nodular hyperplasia from other focal hepatic lesions. Other lesions, namely, hepatocellular adenoma and carcinoma, can have reticuloendothelial uptake, but usually to a lesser degree than that of focal nodular hyperplasia.

Adult↗
PubMed1999

Pediatric liver neoplasms: a radiologic-pathologic correlation.

Only 1-2 % of all pediatric tumors occur in the liver. Two thirds of these tumors are malignant and almost all of the tumors cause clinical symptoms due to their mass effects. Besides the poor prognosis in most of the malignant tumors, for further treatment the origin and nature of the neoplasm has to be known. Due to the mostly unimpeded growth into the peritoneal cavity, the origin of the tumors is primarily often unclear and can non-invasively only be determined by advanced imaging techniques. The display of the macro- and microhistological key features of primary pediatric liver neoplasms, including hepatoblastoma (HB), infantile hemangioendothelioma (IHE), mesenchymal hamartoma (MH), undifferentiated (embryonal) sarcoma (UES), and hepatocellular carcinoma (HCC), together with their imaging representation by ultrasound, computed tomography, and magnetic resonance imaging, may deepen the understanding of the underlying pathology and its imaging appearance. Furthermore, in many cases sufficient information may be provided not only to differentiate benign from malignant tumors, but also to guide for adequate treatment.

Carcinoma, Hepatocellular↗
PubMed1999

New formula for quantification of pleural effusions from computed tomography.

The authors develop a method to accurately and easily estimate the volume of pleural effusions with computed tomography (CT). In 15 patients with either simple or loculated pleural effusions (14 right-sided and 11 left-sided), routine helical CT examinations of the thorax were obtained. Two experienced radiologists visually estimated the volume of the effusions. Three-dimensional reconstructions of the pleural effusions were performed from the helical CT examinations, and the volumes of the effusions were calculated. Effusion volumes were also estimated using the formula d2 x l (d = greatest depth of the effusion on a single CT image, l = greatest length of the effusion). The computer calculated the estimated volumes and they were then statistically compared. The coefficient of correlation between the estimation by measurement and calculated volumes of all effusions was 0.908 (p<0.0001) for the right side, and 0.849 for the left side (p<0.002). Excluding the loculated effusions, the coefficient of correlation was 0.969 for the right side and 0.949 for the left side (p<.001). The volume estimation by visual inspection was also correlated to the calculated volumes (0.84 on the left and 0.85 on the right, p<0.008), but resulted in a consistent overestimation by 300 ml to 500 ml. Although pleural effusion volumes can be estimated by visual inspection with good correlation, some overestimation is consistently seen. Use of the formula d2 x l readily enables estimation of pleural effusion volume from CT, from two simple measurements. This formula-based method of volume estimation provides an accurate and easily measured means of estimation that is readily obtained from routine CT of the chest.

Humans↗
PubMed1999

Radiation effective doses to patients undergoing abdominal CT examinations.

PURPOSE: To determine the radiation effective dose to adult and pediatric patients undergoing abdominal computed tomographic (CT) examinations. MATERIALS AND METHODS: Technique factors were obtained for three groups of randomly selected patients undergoing abdominal CT examinations: 31 children aged 10 years or younger; 32 young adults aged 11-18 years; and 36 adults older than 18 years. The radiographic techniques, together with the measured cross sections of patients, were used to estimate the total energy imparted to each patient. Each value of energy imparted was subsequently converted into the corresponding effective dose to the patient, taking into account the mass of the patient. RESULTS: All abdominal CT examinations were performed at 120 kVp with a section thickness of approximately 7 mm for all sizes of patients. The mean number of CT sections increased from 22.0 for children to 31.5 for adults, and the mean quantity of x radiation in milliampere-seconds increased from 220 mAs for children to 290 mAs for adults. The mean values (+/- SD) of energy imparted were 72.1 mJ +/- 24.4 for children, 183.5 mJ +/- 44.8 for young adults, and 234.7 mJ +/- 89.4 for adults. The corresponding mean values of patient effective dose were 6.1 mSv +/- 1.4 for children, 4.4 mSv +/- 1.0 for young adults, and 3.9 mSv +/- 1.1 for adults. CONCLUSION: Values of energy imparted to patients undergoing abdominal CT examinations were a factor of three higher in adults than in children, but the corresponding patient effective doses were 50% higher in children than in adults.

Abdomen↗
PubMed1999

Pulmonary mucosa-associated lymphoid tissue lymphoma: CT and pathologic findings.

OBJECTIVE: The objective of this study was to determine the CT findings in pulmonary mucosa-associated lymphoid tissue lymphoma and to correlate these CT findings with histologic specimens. CONCLUSION: In the 11 patients reviewed, the most common CT appearance of pulmonary mucosa-associated lymphoid tissue lymphoma was consolidation with air bronchograms, correlating histologically with a cellular lymphocytic infiltrate expanding the interstitium and compressing adjacent alveoli, producing air bronchograms.

Female↗
PubMed1998

Benign lesions of the liver.

Although many hepatic lesions can overlap significantly in their imaging appearance, an imaging approach that is based upon identifying the pathologic and functional components of a lesion can aid in distinction from other entities. In this manner, the diagnostic evaluation can be tailored using the appropriate imaging modality for the lesion at hand. An understanding of the benign liver lesions based on the cellular line of origin and subsequent functional components aids in grasping their expected imaging appearance and may aid in their distinction from malignant tumors. Thus, an imaging approach leading to diagnosis of these tumors should be based on this underlying knowledge of the functional components and cells within the lesion to be studied. For lesions with Kupffer's cell activity, such as FNA, Tc-99m sulfur colloid scan or MR imaging with SPIO may yield the most diagnostic information. For lesions such as hepatic cysts or angiomyolipoma, the diagnosis is usually not a dilemma. For hemangiomas, the most commonly encountered benign hepatic lesion, distinction from other entities may be readily apparent from the initial CT scan or US examination, or it may require additional evaluation with MR imaging. Finally, for other lesions with many cellular components, such as HCA, the imaging findings may not be specific enough by any modality to preclude tissue diagnosis. In any case, it is important to know the diagnostic accuracy and limitations of the imaging modalities available for assessment of any given benign hepatic mass.

Adenoma, Bile Duct↗
PubMed1998

Imaging of diffuse liver disease.

Imaging can play an important role in the diagnosis and planning of treatment for patients with diffuse liver disease. In certain entities, such as iron overload disorders, fatty change, Budd-Chiari syndrome, and schistosomiasis, the imaging findings are characteristic and diagnostic. In others, the findings are less specific, but imaging still has utility in assessment for associated changes of cirrhosis and portal hypertension. In either case, familiarity with these diffuse hepatic diseases and their expected imaging findings enables an organized and thoughtful assessment, with careful attention paid to the key diagnostic features and the important sequlae, such as portal hypertension and the development of HCC.

Humans↗
PubMed1998

Epstein-Barr-virus-associated lymphoproliferative disease of the lung: CT and histologic findings.

PURPOSE: To assess the computed tomographic (CT) and histologic findings of intrathoracic lymphoproliferative disease (LPD) associated with the Epstein-Barr virus (EBV). MATERIALS AND METHODS: The authors retrospectively reviewed the CT scans of the chest and the pathologic specimens obtained in 24 patients with histologically proved intrathoracic LPD and with positive serologic findings or immunohistochemical staining for EBV. Five patients had acquired immunodeficiency syndrome (AIDS); one had common variable immune deficiency; and 18 were receiving immunosuppressive therapy for heart, lung, or heart-lung (n =15) or bone marrow (n = 2) transplantation and vasculitis (n = 1). RESULTS: Final diagnoses included malignant lymphoma (n = 15), polyclonal LPD (n = 8), and hyperplasia of bronchus-associated lymphoid tissue (n = 1). CT findings included multiple nodules (n = 21), lymphadenopathy (n = 9), areas of groundglass opacification (n = 8), septal thickening (n = 7), consolidation (n = 5), pleural effusion (n = 4), and solitary endobronchial lesion (n = 2). The nodules were 2-4 cm in diameter, involved mainly the middle and lower lung zones, and frequently had a predominantly peribronchovascular (n = 15) or subpleural (n = 14) distribution. CONCLUSION: EBV-associated LPD may range from benign lymphoid hyperplasia to high-grade lymphoma. The most common CT manifestation consists of multiple nodules, frequently in a predominantly peribronchovascular or subpleural distribution.

AIDS-Related Opportunistic Infections↗
PubMed1998

Three-dimensional volumetric assessment of abnormally low attenuation of the lung from routine helical CT: inspiratory and expiratory quantification.

OBJECTIVE: The purpose of this investigation was to quantitatively assess abnormally low attenuation of the lung by use of three-dimensional volumetric reconstructions from routine helical CT and to assess their correlation with pulmonary function tests. MATERIALS AND METHODS: Helical CT was performed in 100 patients in full inspiration. Examination was also performed in full expiration in 53 of these patients. Three-dimensional volumetric reconstructions were performed for total lung volumes at inspiration and at expiration, with a threshold of -896 H on inspiratory CT and -790 H on expiratory CT, to quantify emphysematous change. Correlation was made with pulmonary function tests in 79 patients. RESULTS: CT volumetric assessments of abnormally low attenuation of the lung at inspiration and expiration had a high correlation (r2 = .84, p < or = .0001). In comparison with pulmonary function tests, both inspiratory low attenuation of the lung and expiratory low attenuation of the lung correlated well with the logarithm of the ratio of the forced expiratory volume in 1 sec (FEV1) to the forced vital capacity (r2 = .74, p < or = .0001 and r2 = .74, p < or = .0001, respectively) and with the percentage of predicted ratio of the FEV1 to the forced vital capacity (r2 = .69, p < or = .0001 and r2 = .69, p < or = .0001, respectively). Linear correlations were also seen with FEV1, residual volume, and forced residual capacity. CONCLUSION: Three-dimensional volumetric reconstructions of hypoattenuating lung correlate well with pulmonary function tests. In addition, inspiratory and expiratory data are also correlative, suggesting that a dedicated expiratory examination is not needed. This easily obtainable information will prove useful for patients with obstructive lung disease from emphysema, providing a measure of pulmonary function status in this population.

Adolescent↗
PubMed1998

Significance of radiographic cardiomegaly in orthotopic heart transplant recipients.

OBJECTIVE: The purpose of this study is to evaluate the clinical significance of radiographic cardiomegaly in orthotopic heart transplant recipients and to identify causative anatomic and physiologic parameters. MATERIALS AND METHODS: We retrospectively compared the cardiothoracic ratio (CTR) measured using standard posteroanterior chest radiography with left ventricular end-diastolic diameter and left ventricular ejection fraction measured on two-dimensional echocardiography; right ventricular systolic pressure; and systolic, diastolic, and mean blood pressure measured at biopsy in 46 heart transplant recipients. RESULTS: Twenty-eight (61%) of the 46 patients had radiographic cardiomegaly. When we compared heart transplant recipients who had a CTR greater than 0.5 with recipients who had a CTR less than or equal to 0.5, we found no significant difference between their respective left ventricular end-diastolic diameters, left ventricular ejection fractions, right ventricular systolic pressures, systolic blood pressures, or mean blood pressures. A statistically significant difference existed between the mean values of diastolic blood pressure for transplant recipients with and without radiographic cardiomegaly. We found no significant correlation between CTR and left ventricular end-diastolic diameter, left ventricular ejection fraction, systolic blood pressure, diastolic blood pressure, or mean blood pressure. CONCLUSION: The statistically significant difference between the mean values of diastolic blood pressure of transplant recipients with and without radiographic cardiomegaly is clinically insignificant and unlikely to account for the finding of radiographic cardiomegaly. We conclude that radiographic cardiomegaly, which occurs frequently in heart transplant recipients, does not correlate with anatomic or physiologic parameters obtained under the same conditions. Radiographic cardiomegaly in heart transplant recipients does not connote allograft dysfunction or heart failure.

Adult↗
PubMed1997

Tunnel placement in anterior cruciate ligament reconstruction: MRI analysis as an important factor in the radiological report.

OBJECTIVE: Correct placement of tunnels for anterior cruciate ligament (ACL) reconstruction is of prime importance for the clinical outcome of the patient. In this study, the possibility of using MRI to document tunnel placement and provide a more comprehensive report following ACL reconstruction was explored at no additional cost in patients scheduled for routine knee MRI DESIGN AND PATIENTS: One year after ACL reconstruction, 45 patients underwent clinical examination (IKCD score), radiographic examination, and MRI using a 1.5-T unit. RESULTS: Twenty patients with good tibial and femoral attachment results were found at clinical examination to have a stable knee joint with a full range of motion. In 25 patients with suboptimal placements, examination showed either a stable knee with a decreased range of motion or instability with a normal range of motion. CONCLUSION: Patients' clinical outcome, and the radiographic and MRI findings, correlated closely with the quality of operative tunnel placement. A record of this finding is important for completeness of the radiological report. Furthermore the MRI findings can be used to improve the surgical quality of tunnel placement. Because tunnel placement can be shown adequately with radiography, however, MRI cannot be justified for this reason alone, so such assessment is advised only when MRI is needed to show all postoperative features.

Adult↗
PubMed1997

Low density barium and bentonite mixture versus high density barium: a comparative study to optimize negative gastrointestinal contrast agents for MRI.

The purpose of this study was to compare the patient tolerance and efficacy, as magnetic resonance imaging negative oral contrast agents, of a mixture of clay compound bentonite and low density barium sulfate suspension with that of higher density barium sulfate. Twenty patients were randomized into two groups: 10 patients receiving a mixture of low concentration 60% w/v barium sulfate plus 2.5% w/v bentonite, and 10 patients receiving 220% w/v barium sulfate Liuqid-HD (E-Z-EM, Westbury, NY). Post-contrast Spin-echo (SE) T1- and T2-weighted images (WI) were obtained on a 1.0T magnet. Two independent readers scored the overall intraluminal signal intensity and delineation of the gastrointestinal tract and adjacent organs. Patient acceptance was evaluated via a short questionnaire, by recording spontaneous comments and documenting the quantity of contrast agent ingested. There was greater intraluminal bowel signal reduction and organ delineation with 220% w/v barium than with the barium-bentonite mixture on both SE T1WI (p = 0.03) and SE T2WI (p = 0.42). With both agents there was greater signal reduction on SE T2WI than SE T1WI. Higher scores for organ delineation for both contrast agents were seen with SE T1WI. With 220% w/v barium, there was significantly better delineation of the pancreatic body (p = 0.02) and pancreatic tail (p = 0.02) on T1WI compared with SE T2WI. With the barium-bentonite mixture, SE T1WI showed improved delineation of jejunum compared with SE T2WI (p = 0.03). There were no statistically significant differences between the volume of contrast ingested in the two groups. Abdominal cramps were recorded for one patient in each group. These results suggest that barium-bentonite mixture, although useful as a negative gastro-intestinal contrast agent, is not as effective as 220% w/v barium. Further studies with a larger patient population and concentration optimization studies are needed.

Abdomen↗
PubMed1997

MR imaging of inflammatory disease of the liver.

Although MR imaging has achieved a clear role in the assessment of focal benign and malignant hepatic lesions, its role in the evaluation of inflammatory processes in the liver is less well defined and studied. Many inflammatory diseases in the liver have no characteristic or specific imaging findings with MR imaging. Familiarization with these entities and their respective imaging findings is important, however, to aid in their identification and distinction from the more commonly studied neoplastic disease.

Amyloidosis↗
PubMed1996

Cystic masses of the spleen: radiologic-pathologic correlation.

Many focal splenic lesions may appear to be cystic at cross-sectional imaging. In this article, the following types of cystic splenic masses are discussed: congenital (true cyst), inflammatory (abscesses, hydatid cyst), vascular (infarction, peliosis), posttraumatic (hematoma, false cyst), and neoplastic (hemangioma, lymphangioma, lymphoma, metastasis). The key findings at ultrasound, computed tomography, and magnetic resonance imaging can be correlated with underlying gross and microscopic pathologic findings. Although tissue sampling is still required in many cases to yield a definitive diagnosis, recognition and understanding of the spectrum of imaging and pathologic features of these lesions often help narrow the differential diagnosis.

Cysts↗
PubMed1996

Ring enhancement in ultrasmall superparamagnetic iron oxide MR imaging: a potential new sign for characterization of liver lesions.

OBJECTIVE: We performed this study to evaluate the incidence and significance of ring enhancement after i.v. administration of an ultrasmall superparamagnetic iron oxide (USPIO) particle (Code 7227), a reticuloendothelial contrast agent with potential use as a blood-pool agent, for characterizing focal hepatic lesions. SUBJECTS AND METHODS: Conventional T1-weighed imaging, fat-suppressed T1-weighted imaging, conventional T2-weighted imaging, and fast T2-weighted imaging of the liver were obtained in 27 patients with 43 liver lesions before and after i.v. administration of a USPIO preparation. All lesions were larger than 1 cm; 29 were malignant and 14 were benign. Diagnosis was confirmed in all cases, either pathologically (19 patients) or by follow-up examination (eight patients). Two readers independently evaluated each pulse sequence for the presence of ring enhancement of hepatic lesions. RESULTS: Ring enhancement was noted only on T1-weighted images, with no ring enhancement evident on T2-weighted images. Twenty of 43 (47%) lesions showed ring enhancement, including 18 of 29 (62%) malignant lesions and two of 14 (14%) benign lesions (p < .011); Wilcoxon signed rank test). Fat-suppressed T1-weighted imaging showed ring enhancement better than or equal to conventional T1-weighted imaging in all cases, with ring enhancement of 15 of 18 (83%) malignant lesions and two of two benign lesions better demonstrated on fat-suppressed T1-weighted imaging sequences (p < or = .025). CONCLUSION: Ring enhancement after i.v. administration of Code 7227 is a frequent finding seen more often with malignant than benign lesions, potentially identifying a new MR imaging feature for the characterization of liver lesions. The identification of ring enhancement on T1-weighted images attests to the significant blood-pool effects of USPIO particles.

Contrast Media↗