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Biomedical subjects

J H Sumkin

Publications and source records attributed to J H Sumkin.

At least 19 recordsLinked to original sources
PubMed2000

Effects of luminance and resolution on observer performance with chest radiographs.

PURPOSE: To examine the combined effects of image resolution and display luminance on observer performance for detection of abnormalities depicted on posteroanterior chest radiographs. MATERIALS AND METHODS: A total of 529 radiographs were displayed on a specially constructed view box at three luminance levels (770, 260, and 85 cd/m(2)) and three resolutions (100-microm, 200-microm, and 400-microm pixels). Each image was reviewed nine times by six radiologists who participated in this study. The abnormalities included nodule, pneumothorax, interstitial disease, alveolar infiltrates, and rib fracture. Negative (normal) radiographs were also included. RESULTS: Receiver operating characteristic curves indicated that the effect of image luminance was greater than that of resolution. The detection of pneumothorax, interstitial disease, and rib fracture showed statistically significant differences (P <. 05) due to luminance. The detection of pneumothorax was the only abnormality with a statistically significant difference due to resolution. There was no evidence that luminance was related to image resolution for any of the abnormalities. CONCLUSION: At a resolution of 400-microm pixels or higher across the field of view and a luminance of 260 cd/m(2) or more, primary diagnosis with posteroanterior chest radiographs is not likely to be affected by the quality of display.

Analysis of Variance↗
PubMed2000

Use of preoperative MR imaging in the management of endometrial carcinoma: cost analysis.

PURPOSE: To compare the cost of magnetic resonance (MR) imaging and its ability to direct the use of lymph node dissection with the cost and ability of conventional surgery for the staging of endometrial carcinoma. MATERIALS AND METHODS: Preoperative MR images of 25 patients who underwent hysterectomy for endometrial carcinoma were retrospectively evaluated. MR imaging results were compared with those of intraoperative gross dissection of the uterus and final histopathologic examination. Medicare reimbursements for two scenarios were compared in each patient. In the MR imaging scenario, the necessity for lymph node dissection was based on MR imaging results and histologic findings at biopsy. In the actual scenario, lymph node dissection was performed at the surgeon's discretion on the basis of findings at gross dissection of the uterus and histologic examination at biopsy. RESULTS: The cost of the MR imaging scenario, as defined by Medicare reimbursements, was 1% ($1, 265/$148,500) less than that of the actual scenario. In the MR imaging scenario, all patients who required lymph node dissection received it, and 86% of the lymph node dissections performed were necessary. In the actual scenario, one necessary lymph node dissection was not performed, and only 31% of the lymph node dissections performed were necessary. CONCLUSION: Staging with MR imaging has costs and accuracy similar to those of the current method of staging with intraoperative gross dissection of the uterus. In addition, MR imaging decreases the number of unnecessary lymph node dissections.

Adult↗
PubMed1999

Computerized localization of breast lesions from two views. An experimental comparison of two methods.

RATIONALE AND OBJECTIVES: The authors compared two computerized methods, the arc and cartesian straight-line, for the localization of breast lesions in two mammographic views. METHODS: A total of 571 craniocaudal and 571 mediolateral oblique matched mammographic image pairs (or 1142 individual images) depicting 290 pathology-verified masses on both views were selected from our image database. Using a previously developed computer-aided detection scheme, all 290 masses and 3992 suspicious but negative regions were identified. After pairing all identified regions from both views, all masses (true-positive-true-positive matched pairs) and a total of 10330 false-positive pairs (including false-positive-false-positive, true-positive-false-positive, and false-positive-true positive pairs) were assessed as to their position in relation to the nipple using both the arc and the cartesian straight-line methods. Receiver operating characteristic methodology was used to evaluate the performance levels for each method in determining, based solely on location, whether a pair of suspicious regions represented a true mass or a false-positive combination. RESULTS: The areas under the receiver operating characteristic curves (Az) were 0.79 and 0.78 for the arc and cartesian straight-line methods, respectively. The difference between the two techniques (as measured by Az) was not statistically significant (P > 0.99). CONCLUSIONS: These preliminary results demonstrated that the two methods are comparable in identifying true masses from triangulated observations on two views. However, the arc method is somewhat favorable because only the nipple location is required for localization.

Biopsy↗
PubMed1999

Observer sensitivity to small differences: a multipoint rank-order experiment.

OBJECTIVE: To evaluate observer sensitivity to small differences in image presentation, a multipoint rank-order experiment was used to identify small differences or trends in observations. MATERIALS AND METHODS: Ten observers were presented with 50 sets of breast images that had been compressed at five different levels. Each set contained six images ranging from noncompressed to approximately 101:1 compression. Observers were asked to review all images of a case side by side and rank order the quality of each to enable determination of the presence or absence of masses and clustered microcalcifications. RESULTS: As a group, observers were able to detect small differences among the images, even at the lower compression levels (p < .001). As compression levels and image degradation increased, the ability to identify differences between different modes also increased. Large observer variability in discrimination ability was observed. CONCLUSION: Multipoint rank ordering of images viewed side by side can be an efficient method to identify small differences in image presentation. This approach to image ranking could be used to rule out or confirm the need for objective observer performance-type studies.

Breast Diseases↗
PubMed1998

Computed radiography versus screen-film mammography in detection of simulated microcalcifications: a receiver operating characteristic study based on phantom images.

RATIONALE AND OBJECTIVES: The authors compare a 43-micron computed radiographic system with a mammographic screen-film system for detection of simulated microcalcifications in an observer-performance study. MATERIALS AND METHODS: The task of detecting microcalcifications was simulated by imaging aluminum wire segments (200-500 microns in length; 100, 125, or 150 microns in diameter) that overlapped with tissue background structures produced by beef brisket. A total of 288 such simulations were generated and examined with both computed radiography and conventional screen-film mammography techniques. Computed radiography was performed with high-resolution plates, a 43-micron image reader, and a 43-micron laser film printer. Computed radiographic images were printed with simple contrast enhancement and compared with screen-film images in a receiver operating characteristic study in which experienced readers detected and scored the simulated microcalcifications. Observer performance was quantitated and compared by computing the area under the receiver operating characteristic curve. RESULTS: Although the resolution of the computed radiography system was better than that of commercial systems, it fell short of that of screen-film systems. For the 100-micron microcalcifications, the difference in the average area under the curve was not statistically significant, but it was significant for the larger simulated microcalcifications: the average area under the curve was 0.58 for computed radiography versus 0.76 for screen-film imaging for the 125-micron microcalcifications and 0.83 versus 1.00, respectively, for the 150-micron microcalcifications. CONCLUSION: Observer performance in the detection of small simulated microcalcifications (100-150 microns in diameter) is better with screen-film images than with high-resolution computed radiographic images.

Breast Diseases↗
PubMed1998

Lactating adenoma: US features and literature review.

PURPOSE: To describe the ultrasonographic (US) features of adenoma in a lactating breast. MATERIALS AND METHODS: The US scans of 11 lactating adenomas in nine patients aged 25-36 years examined in 1991-1996 were retrospectively reviewed. In all lesions, diagnoses were cytologically or histologically proved after US-guided fine-needle aspiration biopsy (eight lesions) or core biopsy (three lesions). Six patients were lactating, and three patients were in the third trimester of pregnancy. The US features analyzed were shape, orientation to the chest wall, border characteristics, echogenicity, homogeneity, enhancement or shadowing, and depth within the breast. RESULTS: Most lesions had benign US features such as ovoid shape with the long axis parallel to the chest wall (10 of 11), well-defined margins (eight of 11), homogeneous echotexture (eight of 11), and posterior acoustic enhancement (10 of 11). Four lesions had US features that resembled malignant lesions, such as irregular margins, heterogeneous echotexture, and posterior acoustic shadowing. CONCLUSION: The US features, although generally benign, are not specific. Tissue sampling with fine-needle aspiration biopsy is recommended. Core biopsy is necessary if a diagnosis cannot be made with the aspirate but is not performed initially because of the possibility of milk fistula formation.

Adenoma↗
PubMed1997

Preliminary clinical evaluation of a high-resolution telemammography system.

RATIONALE AND OBJECTIVES: The authors designed, assembled, tested, and clinically evaluated a high-quality, fast, and relatively inexpensive telemammography system. METHODS: The authors designed a telemammography system that uses a high-resolution film digitizer and high data compression (> or = 40:1) to send images over regular telephone lines to a high-resolution laser printer that produces images with the look and feel of the original image and can operate in a hub and spokes mode. The authors then evaluated the system's performance. In a preliminary clinical study, interpretations of the laser-printed system's output of 119 cases were compared with the original interpretations, followed by a review of any clinically significant differences. RESULTS: With the exception of the laser printer, which is a modified off-the-shelf product, all hardware components of the system are commercially available products. The system digitizes (50 microns pixel size), compresses, transmits, receives, decompresses, and prints a 30 MB mammography file in less than 4 minutes. In the clinical study, there were 13 differences (in 13 cases) in the level of concern or recommendations. Seven were found to be clinically insignificant by a third-party review. The remaining six were reviewed by the original interpreter, and three were determined to be significant enough for further action. All were found to result from intra-reader variability rather than differences in visualization of possible abnormalities. CONCLUSIONS: Almost real-time, high-quality telemammography without geographic boundaries is possible with the use of high-level data compression. Telemammography with laser-printed film as the display may make it possible to offer mammographic services in remote locations while using commercially available technology.

Evaluation Studies as Topic↗
PubMed1995

Automated large-core needle biopsy of surgically removed breast lesions: comparison of samples obtained with 14-, 16-, and 18-gauge needles.

PURPOSE: To determine the needle size that would consistently enable the pathologist to correctly diagnose tissue core biopsy specimens. MATERIALS AND METHODS: Fifty-seven surgically removed mass lesions of the breast were sampled with a short-throw automated biopsy gun and an 18-gauge needle first, followed by a 16- and a 14-gauge needle. Samples were evaluated independently by three pathologists, and findings were compared with the final diagnosis made at surgical excision biopsy. RESULTS: The sensitivity for the diagnosis of all 26 malignant lesions was 100%, 92%, and 65% for biopsy samples obtained with 14-, 16-, and 18-gauge needles, respectively. Specificity for malignancy was 100% for all three needle sizes. All of the benign diseases were correctly diagnosed in samples obtained with all three size needles except for two samples that did not survive processing. CONCLUSION: Biopsy samples obtained with a 14-gauge needle provide the most accurate diagnosis, which correlates with the diagnosis made with the surgical excision biopsy technique.

Automation↗
PubMed1994

Diagnostic reading session: temporal patterns and case-order effects.

The authors analyzed receiver-operating-characteristic studies to determine temporal patterns and performance as a function of the elapsed time in a reading session. Nineteen radiologists each read as many as 300 chest images with use of seven different display modalities, including conventional and laser-printed film and high-resolution soft display. With a computerized reporting system, the ratio of observers' interpretation rates (time to diagnosis) were recorded for the last five and 10 compared with the first five and 10 of 30-40 cases seen in sessions lasting 45-110 minutes. Observers tended to accelerate their interpretation as the sessions progressed by an average of 15% (P < .001). The acceleration was consistent for all readers (both fast and slow) with a variety of display modes under the nonrestricted time environment.

Humans↗
PubMed1993

Contemporary radiologic percutaneous abscess drainage in the pelvis.

In summary, PAD of pelvic abscesses is an established radiologic procedure. The procedure has gained wide acceptance as an adjunct in the management of patients with pelvic abscess. The procedure involves minimal trauma, is well tolerated, and produces early relief of symptoms. In many instances, it may shorten the length of the hospital stay, reduce costs, and often eliminate the need for surgical intervention. In selected patients, PAD may serve as a temporizing measure in a critically ill or endstage patient. Initial results of PAD treatment of TOA are encouraging, suggesting that this procedure, just as elsewhere in the abdomen, is safe and effective, but larger series are required and long-term follow-up is necessary for evaluation of the cure rate, rate of recurrence, and possible complications.

Abdominal Neoplasms↗
PubMed1991

CT appearance of the Roux limb following choledochojejunostomy in liver transplantation.

Choledochojejunostomy in Roux-en-Y is a frequent form of biliary reconstruction in liver transplants. On computed tomography (CT), fluid in the Roux limb may simulate a fluid collection. We studied the CT appearance of the Roux jejunal limb in 25 normal and complicated liver transplant patients. The Roux limb was identified in 21 (84%) of 25 cases. Most frequently useful features were characteristic location, continuous tubular appearance, biliary stent, "bull's eye" appearance, and gas in the loop. Two of 18 normal Roux loops were initially suspected of being abscesses and one gas-containing abscess was initially mistaken for the Roux limb. In five of seven patients with complications (four abscesses, two bile leaks, one anastomotic hemorrhage), identification of the Roux limb was possible and was useful in interpreting CT scans. Knowledge of the appearance of the normal and abnormal Roux limb is essential for proper interpretation of CT scans in liver transplant patients.

Abscess↗
PubMed1991

US-guided venipuncture for venography in the edematous leg.

A technique for sonographic-guided venipuncture was developed especially for venography made difficult by gross leg edema. Five patients were evaluated in whom venography had been attempted but was initially unsuccessful because of difficult venous access. All five underwent successful venipuncture after sonographic localization of a vein. Ultrasound-guided venipuncture is simple and useful when venous access by palpation is difficult.

Bloodletting↗
PubMed1990

The effect of clinical history on chest radiograph interpretations in a PACS environment.

The effect that accompanying patient information has on diagnostic accuracy in radiologic interpretation has been studied by many researchers but remains a matter of contention. Experiments in the past emphasized the chest film because this procedure is the one done most frequently in radiology. However, with the increasing importance of digital imaging, the role of patient history in these procedures should be assessed. The use of a model computerized patient history in the interpretation of digitized chest images that were displayed on a high-resolution workstation was studied. Two hundred forty-seven selected posteroanterior chest images that indicated disease and that indicated no disease were interpreted in random sequence by five board-certified radiologists, with and without accompanying patient histories. Readers were prompted by the response forms to evaluate images for the possible occurrence of interstitial diseases, nodules, or pneumothorax. No significant differences (P = .05) in the detection of these abnormalities were noted between case readings with and without history for any of the radiologists or for the group as a whole. However, this methodology reflects a direct interpretation approach. The results of this study may not necessarily be applicable to individual prompts, different imaging procedures, or other abnormalities.

Hospital Information Systems↗
PubMed1989

Liver transplant rejection: value of the resistive index in Doppler US of hepatic arteries.

The authors prospectively evaluated the accuracy of the resistive index (RI) in Doppler ultrasound (US) for the detection of the increased vascular resistance that theoretically occurs with acute liver transplant rejection. RIs were calculated for the proximal hepatic artery and a more distal hepatic artery branch in 67 liver transplant recipients. Biopsies were performed within 24 hours of transplantation, with no intervening therapy. Examination of biopsy specimens by a single pathologist revealed findings of no, minimal, or moderate to severe rejection. RIs in hepatic arteries showed no significant differences among the three pathologic groups. No correlation was found between the RI and improved or worsened rejection in 11 patients who underwent biopsy and US more than once. RIs in hepatic arteries are of no value in the prediction of liver transplant rejection.

Acute Disease↗
PubMed1989

Periportal low-attenuation areas on CT: value as evidence of liver transplant rejection.

CT scans of liver transplants may show periportal areas that are lower in attenuation than adjacent portal veins and liver. These areas appear as low-density rims that surround or parallel the portal vein and its intrahepatic branches as well as the immediate subhepatic portal area. In order to determine the value of periportal low attenuation as an indicator of rejection, we reviewed the CT scans of 37 liver transplant patients with biopsy evidence of either acute rejection (12 patients) or nonspecific change without rejection (25 patients). Low-attenuation areas around peripheral portal branches were identified in six of 12 patients with rejection and in four of 25 patients with nonspecific change (sensitivity, 50%; specificity, 84%; accuracy, 73%). The correlation between peripheral periportal low attenuation and rejection was statistically significant (p less than .05). Periportal low attenuation in a central location was seen in eight of 12 patients with acute rejection and in 14 of 25 patients with nonspecific change (sensitivity, 67%; specificity, 44%; accuracy, 51%). The correlation was not statistically significant. Low-attenuation areas were evident on scans obtained either with or without IV contrast enhancement. Periportal low-attenuation areas are commonly seen on CT scans of liver transplants. Peripheral areas correlate with acute rejection, but other factors probably contribute to their occurrence. Central areas do not correlate with acute rejection. Low sensitivity and relatively low accuracy limit the usefulness of peripheral periportal low attenuation as a sign of acute liver allograft rejection.

Adult↗
PubMed1988

Pseudoaneurysms complicating organ transplantation: roles of CT, duplex sonography, and angiography.

In a retrospective study of proved pseudoaneurysms (PAs) in 15 patients with transplanted organs (11 liver, three kidney, one pancreas), the results of computed tomography (CT), duplex sonography, and angiography were reviewed. Of the 15 cases of PA, eight occurred at the arterial anastomosis and seven were nonanastomotic. Three of the eight anastomotic PAs were caused by infection. Of the seven nonanastomotic PAs, four were caused by percutaneous biopsy, two were caused by infection, and one was of undetermined cause. In nine (60%) of the 15 patients the PAs were incidentally detected at imaging studies performed for other reasons. Diagnosis requires a high degree of suspicion. CT was performed in nine cases and duplex sonography in ten. The diagnosis of PA was made with CT in six (67%) patients and with duplex sonography in five (50%). CT and duplex sonography could not enable diagnosis when the PA was small, when the arterial anastomosis was not included in the field of study, or when enhancement with intravenously administered contract material was suboptimal. Angiography depicted the PAs in all 15 patients. In three liver transplant recipients with gastrointestinal tract bleeding, the causative PAs were detected only with angiography.

Adult↗