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Biomedical subjects

G D Dodd

Publications and source records attributed to G D Dodd.

At least 55 records · Page 3Linked to original sources
PubMed1995

Does advanced cirrhosis with portosystemic shunting affect the value of CT arterial portography in the evaluation of the liver?

OBJECTIVE: The purpose of this study was to determine the extent to which reduced portal blood flow in patients with advanced cirrhosis affects contrast enhancement of the liver during CT arterial portography (CTAP). We postulated that reduced and/or irregular hepatic enhancement would limit the efficacy of CTAP for the detection of hepatic tumors in these patients. MATERIALS AND METHODS: We reviewed the records of 82 patients who had biopsy-proved advanced cirrhosis and who underwent CTAP. Three experienced radiologists evaluated the CTAP studies for adequacy of hepatic parenchymal enhancement. The presence or absence of varices also was documented in an attempt to select a subgroup of patients in whom CTAP showed better hepatic parenchymal enhancement. RESULTS: Forty-seven (57%) of 82 patients had inadequate hepatic parenchymal enhancement to allow an evaluation of the entire liver. Inadequacy was attributable to areas of hyperdense parenchymal enhancement, areas of diffuse nontumoral mottling, or zones of poor parenchymal enhancement (soft-tissue attenuation equal to that of the paraspinal muscle). Parenchymal enhancement was inadequate in 62% of patients with varices and in 28% of patients without demonstrable varices. CONCLUSION: Our results show that contrast enhancement of the liver during CTAP is altered significantly in patients with cirrhosis. Thus, it is likely that CTAP has limited usefulness for the detection or characterization of hepatic neoplasms in patients with cirrhosis.

Evaluation Studies as Topic↗
PubMed1995

Imaging in the preoperative evaluation of adult liver-transplant candidates: goals, merits of various procedures, and recommendations.

Advances in organ procurement and surgical techniques have made orthotopic liver transplantation (OLT) an accepted treatment for many adult patients with end-stage hepatic disease. At present, OLT is being performed in patients with a variety of diseases, and 5-year survival is estimated at 65-78% [1]. Over 80% of hepatic transplants are performed in patients with cirrhosis or primary cholestatic liver disease, and only 5% of transplants are performed for malignant hepatic neoplasms (Table 1) [2]. Because the supply of donor organs is limited, preoperative clinical and radiologic evaluation of the transplant candidate is critical for appropriate patient selection. The main objective of preoperative imaging is to provide the surgeon with the pertinent information needed to plan and perform OLT and to exclude patients for whom surgery either is not feasible or will be of no benefit.

Algorithms↗
PubMed1995

Detection of transjugular intrahepatic portosystemic shunt dysfunction: value of duplex Doppler sonography.

OBJECTIVE: Recent reports have shown that a high percentage of patients with transjugular intrahepatic portosystemic shunts (TIPS) have postprocedural shunt complications, including thrombosis of the stent, stenosis of the stent, or stenosis of the hepatic vein draining the stent. We did a prospective study to determine the utility of Doppler sonography as a screening technique for the detection of these complications. SUBJECTS AND METHODS: From September 1991 to September 1992 we placed TIPS in 45 patients. After the procedure, patients were routinely evaluated with both Doppler sonography and angiography. The sonographic protocol consisted of insonation of the stent, portal vein, and hepatic vein to determine the presence of flow, peak velocity, and direction of flow. The angiograms were evaluated for stenoses of the stent or hepatic vein that caused an increase in the portosystemic pressure gradient greater than 15 mm Hg, increased intrahepatic portal venous filling, retrograde filling of the draining hepatic vein, or opacification of varices. The sonographic findings were statistically evaluated to determine if sonography could demonstrate the complications shown by angiography. RESULTS: Adequate follow-up was obtained in 29 of the 45 patients. Sixteen of the 29 patients had shunt complications that consisted of one stent thrombosis, three stent stenoses, nine hepatic vein stenoses, and three concomitant stenoses of the stent and hepatic vein. Flow was not detected by sonography in the stent of the patient with thrombosis. There was a significant difference (p = .003) between the temporal change in peak stent velocity in patients with stenoses versus those without. Use of a change (increase or decrease) in peak stent velocity greater than 50 cm/sec from the post-TIPS baseline sonogram as the diagnostic criterion for the detection of shunt stenoses resulted in a 93% sensitivity and 77% specificity. Five patients with stenosis had reversed flow in the draining hepatic vein. Only one patient with a stenosis had a peak stent velocity less than 50 cm/sec. CONCLUSION: Our results suggest that Doppler sonography is an excellent noninvasive screening technique for the detection of complications of TIPS. We have found a temporal change in peak stent velocity greater than 50 cm/sec to be a more sensitive sonographic sign of TIPS stenosis than the previously reported low-velocity parameters. Our experience suggests that nearly all complications of TIPS can be detected by using three criteria: (1) no flow for thrombosis, (2) a temporal change in peak stent velocity greater than 50 cm/sec for stent and/or hepatic vein stenosis, and (3) reversed flow in the hepatic vein draining the stent for hepatic vein and, rarely, stent stenosis.

Adolescent↗
PubMed1995

Portal vein thrombosis in patients with cirrhosis: does sonographic detection of intrathrombus flow allow differentiation of benign and malignant thrombus?

OBJECTIVE: The objective of our study was to determine if the detection by Doppler sonography of blood flow in portal vein thrombi occurring in patients with cirrhosis could be used to distinguish benign from malignant portal vein thrombi. SUBJECTS AND METHODS: Color and duplex Doppler sonographic examinations were performed in 47 patients with proven cirrhosis and portal vein thrombi. The examinations were directed at the detection of continuous or pulsatile flow within the portal vein thrombi. The nature of the portal vein thrombi was proven histologically in 27 patients and by CT findings and clinical history in 20 patients. The frequency, type, and direction of portal vein thrombus flow was evaluated to determine if there was any correlation with the benign or malignant nature of the portal vein thrombi. RESULTS: Of the 47 patients, 26 had malignant portal vein thrombi and 21 had benign portal vein thrombi. Blood flow was detected in 22 of the malignant and in 15 of the benign portal vein thrombi. The blood flow was pulsatile in 16 malignant and three benign portal vein thrombi and continuous in six malignant and 12 benign portal vein thrombi. The direction of the pulsatile flow in the malignant portal vein thrombi was predominantly (13/16) hepatofugal. All continuous flow in both benign and malignant portal vein thrombi was hepatopetal. The detection of pulsatile flow in portal vein thrombi yielded a 62% sensitivity and 95% specificity for the diagnosis of malignant portal vein thrombus. CONCLUSION: The detection by Doppler sonography of pulsatile flow in portal vein thrombi occurring in patients with cirrhosis is a moderately sensitive but highly specific sign for the diagnosis of malignant portal vein thrombus. However, continuous flow can be detected in benign and malignant portal vein thrombus and is thus not useful in differentiating between the two.

Adult↗
PubMed1995

Sonography of renal transplantation.

Marked improvements in graft survival have made renal transplantation the treatment of choice for end-stage renal disease. Ultrasound, because it is an accurate and noninvasive screening examination for graft dysfunction, clearly has had an impact upon graft survival rates. Gray scale sonography easily detects hydronephrosis and perinephric fluid collections. Vascular complications of transplantation--AVFs, pseudoaneurysms, arterial/venous thrombosis and stenosis--are readily identified by color and duplex Doppler sonography. Initial enthusiasm for the gray scale and Doppler identification of acute rejection largely has been proved to be unfounded. Ultrasound guidance, however, clearly minimizes the risk and discomfort of definitive percutaneous renal transplant biopsy.

Humans↗
PubMed1994

Mammography quality assurance programs.

A quality assurance program is an integral part of a department of radiology, but certain examinations require a more specialized approach than others. The need for greater quality control in mammography was recognized by the American College of Radiology in 1987. The voluntary program developed by this organization has greatly improved the overall quality of mammography in almost three fourths of the facilities in this country. The principles of this initiative now have been adopted by various state and federal agencies, but a uniform approach has not yet been finalized. Optimally, the best aspects of all of these programs will be integrated, resulting in satisfactory image quality, acceptable dosimetry, and an appropriate level of interpretive accuracy in all mammography installations.

Accreditation↗
PubMed1994

Ultrasonically guided fine-needle aspiration biopsy of portal vein thrombosis: a cytomorphological study of 14 patients.

Portal vein tumor thrombosis is an important and consistent prognostic indicator in hepatocellular carcinoma. We reviewed 14 cases of ultrasonically guided fine-needle aspiration biopsy (FNAB) of the portal vein. All the patients had clinical evidence of portal vein thrombosis (PVT). Twelve of these patients had a preliminary diagnosis of hepatocellular carcinoma while the remaining two, initially, had a clinical diagnosis of end-stage liver disease. The mean age of the patients was 60 years. An average of 1.7 passes per case was made. No clinical complications were encountered. The cytomorphologic features of the aspirated materials were reviewed. Twelve of the 14 cases (85.7%) were judged neoplastic or thought to have probable neoplastic involvement of the portal vein while two were clearly benign. The cell block was found to be the most useful in diagnosis. We conclude that FNAB of the portal vein is a feasible method in evaluating PVT, especially in patients already known to have hepatocellular carcinoma.

Aged↗
PubMed1994

Hepatic CT enhancement: comparison of ionic and nonionic contrast agents in the same patients.

PURPOSE: The authors prospectively compared the effects of ionic and nonionic contrast agents on hepatic enhancement at computed tomography (CT) in the same patient population. MATERIALS AND METHODS: Forty-six patients underwent abdominal CT with either ionic or nonionic contrast agents. At 6-month follow-up, the alternative agent was used. Pre- and postcontrast attenuation values of liver and vessels were obtained; enhancement and postinjection time of each image were recorded. The area under a computer-generated enhancement-time curve was calculated as a means of measuring enhancement over time. Mean liver enhancement with ionic and nonionic contrast agents was compared. RESULTS: Mean hepatic enhancement with ionic contrast material was greater than with nonionic contrast material at all time intervals through 90 seconds after injection. The difference was statistically significant from 61 to 70 seconds. Mean peak liver enhancement for ionic and nonionic contrast agents was nearly identical (59 and 58 HU, respectively), but mean time to peak hepatic enhancement with nonionic contrast agent was greater by 10 seconds. CONCLUSION: These results indicate that ionic contrast agent may effect greater liver tumor conspicuity.

Female↗
PubMed1994

Hepatic artery stenosis and thrombosis in transplant recipients: Doppler diagnosis with resistive index and systolic acceleration time.

PURPOSE: To assess the value of resistive index (RI) and systolic acceleration time (SAT) for diagnosis of stenoses and thromboses of the hepatic artery in liver transplant recipients. MATERIALS AND METHODS: Doppler sonograms and angiograms in 125 liver transplant recipients were correlated and analyzed for any statistically significant difference in the RI or SAT of patients with and without arterial stenosis or thrombosis. Sensitivity and specificity were calculated for RI, SAT, peak arterial systolic velocity, and absence of arterial flow. RESULTS: Forty-seven patients had a marked stenosis; 16 had thrombosis. There was a statistically significant difference (P < .05) in the RI and SAT of patients with stenosis or thrombosis versus those with normal arteries but not in patients with stenosis versus thrombosis. RI and SAT parameters allowed detection of abnormalities not found with peak velocity and no-flow parameters. Combined parameters produced 97% sensitivity and 64% specificity for marked arterial disease. CONCLUSION: Doppler spectral wave form analysis provides excellent screening for detection of hepatic allograft arterial stenosis or thrombosis.

Adolescent↗
PubMed1994

Malignancies in patients with cirrhosis: CT sensitivity and specificity in 200 consecutive transplant patients.

PURPOSE: To determine the sensitivity and specificity of computed tomography (CT) as a screening tool in patients with cirrhosis. MATERIALS AND METHODS: CT examinations were performed before liver transplantation in 200 consecutive patients with cirrhosis. Scans were prospectively reviewed and compared with pathologic findings in the fresh serially sectioned whole livers. RESULTS: Pathologic evaluation revealed hepatocellular carcinoma in 35 patients and cholangiocarcinoma in five. Malignancy was clinically suspected in 18 patients prior to imaging. CT depicted tumor in 25 patients; tumor was identified only at pathologic study in 14 patients. Sensitivity of unenhanced and enhanced CT in detection of malignancy was 63% and 68%, respectively, and specificity was 63% and 81%, respectively. Cysts and hemangiomas were found in only 10 and five patients, respectively. CONCLUSION: CT is insensitive for detection of neoplasms in the cirrhotic liver. Unsuspected malignant neoplasms are encountered more frequently than cysts or hemangiomas. Sensitivity of unenhanced CT for tumor detection is similar to that of enhanced CT; unenhanced CT, however, is less specific for malignancy.

Bile Duct Neoplasms↗
PubMed1994

Optimizing CT portography: a prospective comparison of injection into the splenic versus superior mesenteric artery.

PURPOSE: To evaluate whether computed tomographic arterial portography (CTAP) is best performed with injections in the superior mesenteric artery (SMA) or the splenic artery. MATERIALS AND METHODS: Seventy-one studies were performed with injection into the SMA (n = 37) or splenic artery (n = 34) of 150 mL of contrast material at 1.5 mL/sec and 20-second delay for both groups. Images were reviewed for location and type of nontumoral perfusion abnormalities. The degree of liver parenchymal enhancement with each technique was compared. RESULTS: Fewer nontumoral perfusion defects were seen with splenic artery (65%) versus SMA (78%) injection. Visual differences in contrast enhancement with greater attenuation in dependent portions of the liver were seen with greater frequency with SMA (41%) than with splenic artery (24%) injection. Contrast enhancement that obscured detail in the right lobe was seen only with SMA injections (16%). Greater parenchymal enhancement (up to 18 HU) at all time intervals was seen with splenic artery injection. CONCLUSION: Because of greater parenchymal enhancement and fewer nontumoral perfusion abnormalities, splenic artery catheterization is the preferred technique for CTAP.

Catheterization, Peripheral↗
PubMed1994

Acute renal colic: diagnosis with duplex Doppler US.

PURPOSE: To determine the sensitivity of renal duplex Doppler sonography in the detection of patients with acute renal colic. MATERIALS AND METHODS: The authors correlated results of renal duplex Doppler sonography with those of urography in 32 patients presenting with symptoms of urinary colic. The mean resistive index (RI) of each kidney and the difference between the mean RIs (delta RI) of both kidneys were calculated for all patients. The nonpaired two-tailed Student t test was used to determine if there was a significant difference in parameters between patients with and without obstruction. The sensitivity and specificity of the mean RI and the delta RI for the diagnosis of acute renal colic were calculated. RESULTS: Nineteen patients had obstruction. The differences in the mean RI and delta RI for the patients with and without obstruction were statistically significant. When the published discriminatory thresholds for obstruction (mean RI > or = 0.7, delta RI > or = 0.1) were applied, however, the sensitivity and specificity of the Doppler examination were only 44% and 82%, respectively. CONCLUSION: Duplex Doppler sonography is highly insensitive for the detection of acute renal colic.

Acute Disease↗
PubMed1994

Peribiliary cysts associated with severe liver disease: imaging-pathologic correlation.

OBJECTIVE: Prior pathology reports describe peribiliary cysts in patients who have severe liver disease. The purpose of this study was to determine whether these cysts could be identified on imaging studies, and to determine the range of imaging findings when identified. SUBJECTS AND METHODS: Imaging and pathologic findings were correlated in 12 patients in whom peribiliary cysts were found on gross inspection of the liver after autopsy (one) or liver transplantation. All patients had been examined with CT and sonography, three patients had undergone MR imaging, and one had had cholangiography. The liver was sectioned in the axial plane at 1-cm intervals, and the porta hepatis and the proximal extrahepatic bile ducts were examined macroscopically. Pathologic findings were recorded and compared with the patients' imaging findings and clinical course. RESULTS: CT showed the peribiliary cysts in the porta hepatis in 10 of 12 patients. These appeared as discrete cysts in four patients, a tubular structure paralleling the portal structures in four patients, and a string of cysts that simulated abnormal bile ducts in two patients. Sonography showed the cysts in four of 12 patients, as anechoic cystic structures in three and as a septated, tubular channel in one. MR showed the cysts in two of three patients, and T2-weighted images were better than T1-weighted images. The cysts appeared in a cluster in one patient, and as a tubular structure of high intensity on T2-weighted images that simulated a dilated bile duct in the other. Patients were asymptomatic in 11 of 12 cases. In one case, large cysts caused biliary obstruction, which was apparent on CT scans, sonograms, and cholangiograms. CONCLUSION: Peribiliary cysts associated with a variety of disorders can be detected with CT, sonography, and MR imaging. Recognition of the imaging appearance of these cysts may avoid the misdiagnosis of dilated bile ducts, cystic neoplasm, or abscess. Conversely, when seen on images, these cysts might suggest one of the underlying associated disorders.

Adult↗
PubMed1993

American Cancer Society guidelines from the past to the present.

Guidelines for screening mammography were first suggested by the American Cancer Society in 1977. These have been reviewed periodically, and changes have been made based on the evidence available at the time of review. Two major breast screening studies conducted in the United States have had strong influences on the guidelines. The Health Insurance Plan of Greater New York demonstrated a constant decrease in mortality for women over the age of 50, a finding that was apparent 5 years after the study's completion. At that time, no significant change could be demonstrated in the 40-49-year age group; however, 10 years after the study's conclusion, the decrease for the younger age group had increased to 23.5% and has remained essentially constant. Despite the small number of patients involved, the American Cancer Society considers this decrease in women aged 40-49 years significant. The Breast Cancer Detection Demonstration Project, sponsored by the American Cancer Society and the National Cancer Institute, involved 283,222 women and was conducted under guidelines developed by the Consensus Development Meeting in 1977. The 14-year follow-up for this study continues to show a survival rate in the 80th percentile for women aged 40-49 years. In 1987, 12 organizations examined all existing guidelines in an attempt to develop uniform recommendations that would eliminate some of the confusion surrounding mammography screening. In 1991, following a 2 1/2-day conference sponsored by the American Cancer Society, it was concluded that current evidence did not indicate that a change in the screening guidelines was necessary, with the exception of the omission of the previously recommended baseline study at the age of 35. Future reviews will be conducted as pertinent information becomes available.

Adult↗
PubMed1993

Screening for breast cancer.

To be successful, screening procedures must have certain properties: simplicity, acceptability, reasonable costs, and adequate sensitivity. The evolution of mammography over the past 10 years has allowed the examination to fall within accepted standards for these properties, and it has become a widely accepted procedure. Its expanded use has resulted in an increase in the detection of early stage disease with a profound effect upon the treatment of the disease. Survival continues to correlate with cancer size and nodal involvement, and the increase in the number of early cases diagnosed eventually should be reflected in a decreasing mortality rate. Though the efficacy of screening mammography for women between the ages of 50 and 69 is well-established, its usefulness in women aged 40-49 has provoked considerable debate. Despite the disagreements concerning appropriate screening thresholds and intervals, the American Cancer Society and the American College of Radiology have concluded that sufficient evidence exists to maintain published guidelines.

Breast Neoplasms↗
PubMed1993

Percutaneous transhepatic embolization of an intrahepatic pseudoaneurysm following liver biopsy in a liver transplant patient.

A 41-year-old liver transplant patient had severe hemobilia from an intrahepatic pseudoaneurysm secondary to a liver biopsy. Selective intra-arterial embolization was not technically possible due to marked redundancy and tortuosity of the allograft hepatic artery. The pseudoaneurysm was localized by ultrasound and embolized using a direct percutaneous transhepatic approach. This is a novel way of approaching hemobilia in liver transplant patients after liver biopsy and may avoid the risks of arterial embolization.

Adult↗
PubMed1993

Confluent hepatic fibrosis in advanced cirrhosis: appearance at CT.

To determine the computed tomographic (CT) characteristics of confluent fibrosis complicating liver cirrhosis, CT scans of 420 cirrhotic patients without hepatic malignancy who underwent hepatic transplantation were correlated with freshly resected whole liver specimens. In 59 patients, CT demonstrated 70 focal abnormalities corresponding to confluent fibrosis. The lesions were characterized by shape and location: 49 wedge-shaped lesions radiated from the porta hepatis, eight peripheral bandlike lesions were remote from the porta hepatis, and 13 lesions were seen as total lobar or segmental fibrosis. Associated volume loss was seen in 62 of the 70 lesions as retraction of the overlying hepatic capsule or total shrinkage of the segmental or lobar involvement. At plain CT, all 70 lesions were areas of lower attenuation than adjacent liver. At contrast material-enhanced CT, 51 of 64 lesions were iso-attenuating or minimally hypo-attenuating. The authors conclude that confluent fibrosis has a characteristic appearance at CT. Recognition of its characteristics may help radiologists differentiate confluent fibrosis from hepatic neoplasms in cirrhotic patients.

Adolescent↗