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A H Dachman

Publications and source records attributed to A H Dachman.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Comparative viewing modalities for CT cystography.

BACKGROUND: To define the speed and accuracy of two different reconstructive techniques using computed tomography (CT) cystography for the detection and measurement of urinary bladder masses and determine the overall ease of use. METHODS: Ten patients scheduled for cystoscopy for the evaluation of hematuria or bladder masses were studied by means of thin-section CT of the air-distended bladder. Two techniques were employed by two radiologists to blindly interpret the data: conventional two-dimensional data with interactive three-dimensional problem solving (2D3DPS) and surface-shaded display (SSD) three-dimensional images. The results were compared with the data from cystoscopy. RESULTS: Twenty-two (100%) of 22 masses detected on cystoscopy were visualized using the reconstructive techniques. Both modalities were shown to have high accuracy, but only the 2D3DPS had a sensitivity and specificity of 100% for both observers at the patient-level diagnosis. The sensitivities for detecting individual masses for the two observers were 100% and 64% for 2D3DPS and 64% and 70% for SSD. CONCLUSION: Both methods used to display the CT data had a high sensitivity and specificity for masses, but only the 2D3DPS had a sensitivity and specificity of 100% at the patient-level diagnosis, thus making it a feasible imaging modality for cystography. It was also preferred overall for ease of use, high accuracy, and relative low cost.

Aged↗
PubMedDate not supplied

CT findings of regression in intraabdominal desmoplastic small-cell tumor.

We report the computed tomographic (CT) findings in a patient with intraabdominal desmoplastic small-cell tumor before and after 10 weeks of chemotherapy. This tumor is a rare, frequently fatal neoplasm of the peritoneum, seen predominantly in young males. Initial CT demonstrated large intraperitoneal masses, hepatic metastases, retroperitoneal and right axillary lymphadenopathy, ascites, and pleural effusion. Follow-up CT showed marked decrease of the main tumor bulk and complete regression in the axillary nodes.

Abdominal Neoplasms↗
PubMedDate not supplied

Timing in the normal pharyngeal swallow. Prospective selection and evaluation of 16 normal asymptomatic patients.

A review of timing of pharyngeal events with radiography has been made. A prospective selection of normal asymptomatic patients presenting for a gastrointestinal evaluation was made and timing of 55 events in the videorecorded pharyngeal swallow in these patients was performed. Only 16 normal asymptomatic patients as defined for selection were found among 870 patients presenting for gastroesophageal examination. A detailed description of their timing observations is presented. The timing data were used to temporally order events in the pharyngeal swallow. This ordering of events in the pharyngeal swallow and the data upon which it is based are reported here in detail.

Adolescent↗
PubMedDate not supplied

Calcified intrahepatic portal vein thrombus: distinction from intrahepatic choledocholithiasis.

In a case of calcified intrahepatic portal vein thrombus CT demonstrated a branching calcified intrahepatic mass with peripheral enhancement following dynamic bolus contrast medium administration. The distinction from intrahepatic choledocholithiasis was made with normal cholangiography. Calcified portal vein thrombus should be considered an unusual cause of branching calcified intrahepatic mass on CT.

Adult↗
PubMedDate not supplied

Collateral pathways in superior vena caval obstruction as seen on CT.

PURPOSE: Collateral venous pathways occurring with superior vena cava (SVC) obstruction were examined based on CT scans obtained from the thoracic inlet to the pubic symphysis. Similarities and variations from the prior classification scheme were analyzed. METHOD: A retrospective review of our database resulted in a cohort comprising 21 CT scans from 19 patients. The location and frequency of each collateral pathway and the level of the SVC obstruction were tabulated. An accepted classification scheme was applied to the collateral patterns in each case. Additional and atypical features were noted. RESULTS: Fifteen common collateral veins were found that could be grouped into one to four collateral pathways. Unusual shunts, including hepatic parenchymal and pulmonary pathways, were found. Thirteen cases (62%) varied from the standard classification owing to different occlusion levels or presence of other collaterals. No statistically significant relationship between the level of occlusion and the number of collateral pathway groups was found. The most common abdominal collateral veins were those along the liver surface (52.3% of cases), although 18 patients (94.7%) had at least one collateral vein visible in the abdomen. CONCLUSION: The spectrum of venous collateral formations as seen on thoracoabdominal CT scans often includes collaterals at or below the level of the diaphragm, including intrahepatic shunts. Many collateral patterns found in this series could not be classified with the existent classification scheme.

Adult↗
PubMedDate not supplied

Automated segmentation of colonic walls for computerized detection of polyps in CT colonography.

PURPOSE: A new method for fully automated segmentation of the colonic walls in volumetric CT data was developed for limitation of the search space in computerized detection of polyps. METHOD: For reliable segmentation, an anatomy-oriented approach was used, in which several anatomical structures are segmented in addition to the colon for utilization of their properties. RESULTS: The segmentation method was validated by use of 14 data sets, consisting of cases positive for colonic polyps. We found that the segmented colonic walls included all of the polyps. A subjective rating of the results was performed based on several criteria for visualization of anatomic detail of the colonic wall and mucosal surface. Except for a few cases in which insufflation of the colon was insufficient, all of the results included >95% of the colonic walls. CONCLUSION: This method for colonic wall segmentation is reliable and the segmentation results are applicable in both visualization of the colon and computer-aided diagnosis in the detection of polyps in CT colonography.

Automation↗