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At least 271 records · Page 15Linked to original sources
PubMed2003

Management of soft tissue sarcomas of the abdomen and pelvis.

OBJECTIVE: Soft tissue sarcomas of the abdomen or pelvis are rare tumours that usually arise in the retroperitoneum but may also arise from the gastrointestinal tract or other abdominal organs. The aim of this study was to assess patient outcome following treatment of these tumours at a tertiary referral centre. PATIENTS AND METHODS: Data on all patients with soft tissue tumours treated under the care of one surgeon between January 1990 and December 2000 was reviewed. RESULTS: Over the 11-year period 61 patients underwent 79 operations for a soft tissue sarcoma of the abdomen or pelvis. Macroscopic clearance of tumour at operation was achieved in 45 (74%) of the 61 patients, for primary tumours this was 97%, recurrent tumours 50% and metastases 33%. The median survival for those undergoing complete resection was 50 months (range 3-238 months, median follow-up 33 months). This compared with a median survival of only 6 months range (1-127 months) for those that had incomplete resection (P = 0.001). The 5-year survival for patients that had complete resection was 61.5%, however, over one-third of the 5-year survivors have since recurred. CONCLUSION: This study confirms that most primary soft tissue sarcomas of the abdomen or pelvis are resectable and the majority of patients will experience a long disease free interval following resection.

Abdominal Neoplasms↗
PubMed2005

Phase I/II trial of intravenous Doxil and whole abdomen hyperthermia in patients with refractory ovarian cancer.

OBJECTIVE: A phase I/II study of Doxil combined with whole abdomen hyperthermia was conducted in patients with refractory ovarian cancer. Liposomal doxorubicin combined with hyperthermia has been shown to increase both liposomal delivery and drug extravasation into tumour xenografts resulting in enhanced cytotoxic effects. PATIENTS AND METHODS: Thirty patients with either recurrent or persistent epithelial ovarian cancer were enrolled. All patients had either measurable or assessable disease. Patients received intravenous (IV) Doxil at a dose of 40 mg m-2 as a 1-h infusion followed by whole abdomen hyperthermia. The phase I portion of the study was performed to determine the maximal tolerated dose (MTD) of hyperthermia. Quality of life (QoL) was performed at baseline, prior to each cycle and every 3 months. Plasma pharmacokinetic studies were performed with the first cycle. RESULTS: Ten patients participated in the phase I portion of the study which demonstrated that the MTD of hyperthermia was 60 min after either average vaginal and rectal temperatures of 40 degrees C had been achieved or after 30 min of power application, whichever was shorter. All 30 patients were either paclitaxel and/or platinum resistant initially or developed resistant disease. The median number of prior chemotherapeutic regimens was three (range 2-8) and six patients had been previously treated with Doxil. There were three partial responses for a response rate of 10% (95% CI: [2%, 27%]) and eight patients (27%; 95% CI: [12%, 46%]) had disease stabilization. The median time to progression or death was 3.4 months (95% CI: [2.6, 5.2]) and the median survival was 10.8 months (95% CI: [8.8, 17.4]). Twelve patients (40%) experienced palmar-plantar erythrodysesthesia (PPE), but only four (13%) experienced grade 3-4 PPE toxicity. Doxil systemic exposure was higher in those with grade 3-4 PPE compared to those with no PPE. None of the patients had grade 3-4 thermal toxicity due to hyperthermia. QoL was not decreased in patients responding to therapy. CONCLUSIONS: Therapy with intravenous Doxil and whole abdomen hyperthermia for patients with platinum/paclitaxel resistant ovarian cancer is feasible and does not negatively impact quality of life.

Aged↗
PubMed2002

Clinical uses of diagnostic peritoneal lavage in stab wounds of the anterior abdomen: a prospective study.

OBJECTIVE: To evaluate patients with stab wounds of the anterior abdomen with diagnostic peritoneal lavage (DPL), by using initial aspiration of gross blood from the lavage catheter of more than 10 ml or red blood cell (RBC) count in the lavage fluid of more than 10,000/mm3 as criteria for exploratory laparotomy. DESIGN: Prospective study. SETTING: University hospital, Thailand. PATIENTS: 40 patients who had stab wounds of the anterior abdomen penetrating through the peritoneum but had no obvious indications for immediate exploratory laparotomy. INTERVENTIONS: Diagnostic peritoneal lavage (DPL), exploratory laparotomy. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of positive DPL as an indication for exploratory laparotomy. RESULTS: In 27 patients (68%) the DPL was positive and in 13 (33%) it was negative. In 18 patients (67%) the initial aspiration of gross blood was more than 10 ml and in 9 (33%) the RBC count in lavage fluid was more than 10,000/mm3. These 27 patients had exploratory laparotomies, 2 of which were negative. All 13 patients who had negative DPL were observed and discharged home uneventfully. The sensitivity of DPL for positive laparotomy was 100%, the specificity was 87%, the PPV was 93%, the NPV was 100% and the accuracy was 95%. When operative findings of bleeding from the stab wound into the peritoneal cavity were considered as a "negative" laparotomy (n = 7) the sensitivity, the specificity, the PPV, the NPV and the accuracy became 100%, 59%, 67%, 100%, and 78%, respectively. CONCLUSION: The use of DPL in patients with stab wounds of the anterior abdomen, using initial aspiration of gross blood from the lavage catheter of more than 10 ml or RBC count in the lavage fluid of more than 10,000/mm3 as positive criteria for exploratory laparotomy, is safe and practical.

Abdominal Injuries↗
PubMed2006

The open abdomen in trauma: do infectious complications affect primary abdominal closure?

OBJECTIVE: One of the primary goals of damage control surgery in the trauma patient is primary closure of the abdomen. We hypothesized that extra-abdominal infections, such as those complicating injuries to the thorax, diaphragm, long bones, or musculoskeletal system, would decrease the likelihood of primary abdominal closure and increase hospital resource utilization in patients requiring open abdominal management. METHODS: The trauma registry of the American College of Surgeons (TRACS) was reviewed retrospectively from 1995-2002 for open abdomen technique and damage control surgery. The outcome was primary fascial closure or delayed closure. Patients who died prior to closure were excluded. We evaluated infectious complications, including ventilator-associated pneumonia (VAP), blood stream infection (BSI), and surgical site infection (SSI). Other parameters studied were multiple rib fractures, long bone fractures, chest injuries, diaphragm injuries, empyema, and transfusion requirements. Hospital charges were obtained from the hospital administrative database. Univariate, multivariate, and regression analyses were performed to identify the effects of infectious complications on primary abdominal closure, length of stay, total hospital charges, and disposition. RESULTS: Three hundred forty-four patients required the open abdomen technique: 67% received damage control laparotomy and 33% decompression of abdominal compartment syndrome. Two hundred seventy-six patients (80%) went on to abdominal closure of some form and constituted the primary study group. Primary abdominal closure was achieved in 180 (65%) with a mean time to closure of 3.5 days. Ventilator-associated pneumonia, BSI, and SSI were associated with lack of primary closure (p < 0.05). Increased blood transfusions also were associated with failure of primary closure (p < 0.05). Ventilator-associated pneumonia and BSI were associated with significantly greater lengths of stay in the intensive care unit (ICU) (24.2 days vs. 12.6 days and 30.5 days vs. 17.9 days; both p < 0.0001) and significantly greater total hospital charges (232,080 US dollar vs. 142,893 US dollar; 247,440 US dollar vs. 160,940 US dollar; and 264,778 US dollar vs. 170,447 US dollar; all p < 0.001). CONCLUSION: Inability to achieve primary abdominal closure was associated with infectious complications (VAP, BSI, and SSI) and large transfusion requirements. Infectious complications also significantly increased ICU utilization and hospital charges. Death was associated with BSI, femur fractures, and large transfusion requirements, whereas infectious complications did not have a significant impact on discharge disposition.

Abdominal Injuries↗
PubMed1989

The role of CT scan in evaluation for laparotomy in patients with stab wounds of the abdomen.

Not every patient with a penetrating stab wound of the abdomen requires laparotomy. This report evaluates use of computerized tomographic (CT) scan in assessment of stable asymptomatic patients, with penetrating abdominal stab wounds, as an indicator of the necessity of abdominal exploration. In a prospective study, 50 patients with abdominal stab wounds were treated successfully with observation only, after admission abdominal CT scan interpretation was negative for pathology in 45 patients. In the remaining five it was of such minor nature that conservative management was justified (Series I). Twenty-eight stable asymptomatic patients with penetrating stab wounds of the abdomen comparable to the ones in Series I had CT scan on admission, and then underwent exploratory laparotomy independent of their CT scan findings (Series II). Of these 28 patients, 22 had correct CT scan findings verified by laparotomy, three were false positive for intra-abdominal injury resulting in negative explorations, and three patients had such nonspecific findings as fluid or air in the abdomen incompatible with precise organ injury identification. Our study shows that CT scan in patients with abdominal stab wounds identifies solid organ injury with great specificity and sensitivity, evaluates the retroperitoneum well, and detects peritoneal penetration by demonstrating intraperitoneal fluid or air. CT scan was unreliable in detection of bowel injury and does not demonstrate diaphragmatic injuries.

Abdominal Injuries↗
PubMed1992

Laparoscopy in the evaluation of the intrathoracic abdomen after penetrating injury.

Penetrating trauma to the intrathoracic abdomen is a difficult clinical problem, especially with reference to the detection of diaphragmatic injuries. A retrospective analysis of 657 laparotomies for penetrating abdominal trauma at our institution revealed 78 laparotomies with negative results. The majority (44.8%) were for wounds in the lower chest and upper abdomen. The role of laparoscopy in evaluating these difficult areas was studied in 40 (34 stab wounds and 6 gunshot injuries) patients. Fifteen stab wounds and five gunshot wounds were nonpenetrating. Laparoscopy revealed eight clinically unsuspected diaphragmatic lacerations in seven patients. Twenty patients had hemoperitoneum. Five patients with omental bleeding and abdominal wall bleeding and four with nonbleeding liver lacerations underwent nontherapeutic laparotomies. One patient with a nonbleeding liver laceration was observed successfully without laparotomy. Ten of the 20 patients with hemoperitoneum had therapeutic laparotomies. The incidence of diaphragmatic lesions discovered by laparoscopy in this series was comparable with that reported after a mandatory laparotomy for thoracoabdominal wounds. It is concluded that laparoscopy is an excellent modality for the evaluation of the intrathoracic abdomen and the diaphragm.

Abdominal Injuries↗
PubMed2001

Staged reconstruction after gunshot wounds to the abdomen.

Immediate closure of abdominal incisions after exploration and treatment of gunshot wounds is not always feasible or advisable. Significant bowel edema after massive fluid resuscitation might preclude primary closure, whereas any attempt to close under tension might result in complications ranging from wound dehiscence, infection, and necrosis to the abdominal compartment syndrome with abdominal, cardiopulmonary, and renal complications. For these difficult cases, the open technique has been recommended. The abdomen is left open and is closed when the patient's condition permits. When immediate wound approximation is not possible, temporary coverage can be achieved with a mesh, patch, or a split-thickness skin graft and the definitive reconstruction is deferred for a more optimal time. The purpose of this retrospective study is to report the authors' experience with staged abdominal wall reconstruction after gunshot wounds. From 1989 to 1998, 1933 patients underwent exploratory laparotomy for penetrating wounds to the abdomen. Twenty-nine patients in grave condition and with multiple medical problems were comanaged by the Trauma and Plastic Surgery Services at Cook County Hospital with the following protocol: The abdomen was initially left open and exposed viscera were covered with a variety of methods, including a Gore-Tex patch (W. L. Gore and Associates, Inc., Flagstaff, Ariz.). A split-thickness graft was subsequently placed on the granulation tissue over viscera at an average of 14 days after the last laparotomy. These planned ventral hernias were definitively treated at an average of 7 months after the skin grafting procedure, primarily using the components separation technique. In 24 patients, the fascia was closed primarily without tension, while five patients required the use of synthetic mesh to restore fascial continuity. Nine patients underwent closure of a colostomy or repair of fistulas simultaneously with abdominal wall reconstruction. One patient developed a postoperative hernia, two developed superficial wound dehiscence that healed without further surgery, and one required re-exploration for a failed anastomosis after colostomy closure. All but one patient maintained a stable abdominal wall after the reconstruction. The authors concluded that staged abdominal wall reconstruction should be primarily recommended for patients with complex abdominal wounds and a compromised general condition that precludes primary closure. With this treatment protocol, patients can recover faster from their trauma surgery and the risk of perioperative complications can be reduced. After final reconstruction, the continuity, stability, and strength of the abdominal wall are maintained in the vast majority of cases with the use of autogenous tissue and without the need for alloplastic material. With close cooperation between the trauma team and the plastic surgeon and appropriate timing and planning of each stage, the success rate of the technique is high and the incidence of complications limited.

Abdominal Injuries↗
PubMed2006

Evaluation of the abdomen in the critically ill patient: opening the black box.

PURPOSE OF REVIEW: Evaluation of the abdomen in critically ill patients can be challenging. This article reviews the available data and proposes evidence-based guidelines for evaluation of the abdomen in the critically ill patient. RECENT FINDINGS: The critically ill are often clinically unevaluable due to distracting injuries, respiratory failure, obtundation, or other conditions. Even when patients can be examined, the clinical exam can be unreliable and misleading. Critically ill patients who are sufficiently stable to undergo imaging benefit from computerized tomography unless biliary sepsis is suspected, when ultrasound is preferred. There is an important role for endoscopy and angiography in the setting of gastrointestinal hemorrhage, as well as magnetic resonance imaging for mesenteric ischemia. Critically ill patients who are too unstable for imaging may require bedside laparoscopy or diagnostic peritoneal lavage. Abdominal compartment syndrome should be considered in the differential diagnosis of the unstable critically ill patient. Empiric laparotomy may still need to be employed in diagnosis and management of unstable patients. SUMMARY: Timely and accurate diagnosis of life-threatening intraabdominal pathology is essential to care for critically ill patients. A multitude of laboratory, radiologic, and interventional modalities are available to evaluate the abdomen in the critically ill.

Abdominal Cavity↗
PubMed1982

Burst abdomen and incisional hernia: a prospective study of 1129 major laparotomies.

Burst abdomen and incisional herniation are continuing problems for the general surgeon. A prospective study was carried out to define the extent of the problem. Over five years from 1975 to 1980 a total of 1129 major laparotomy wounds in adults were assessed at regular intervals for 12 months after operation. There were 19 burst abdomens (1.7%) and 84 incisional hernias (7.4%). The introduction of the mass-closure technique reduced the incidence of burst abdomen from over 3% in 1975 to 0.95% in 1979. It did not, however, improve the rate for incisional hernias, which was 7.6% in 1979. Many factors are associated with incisional herniation: old age, male sex, obesity, bowel surgery, type of suture, chest infection, abdominal distension, and, most important, wound infection. More work is needed to find the ideal method of wound closure, and efforts should be made to eliminate wound infection.

Female↗
PubMed1977

Attenuation values in computed tomography of the abdomen.

Attenuation values were obtained from 50 CT examinations of the upper abdomen. A normal range of values, obtained for the organs in the upper abdomen, was compared with patient size and age. Rank ordering according to the mean attenuation values was also performed. The most significant finding was that the liver normally had the highest attenuation value of any of the viscera measured. When another organ in the upper abdomen had a mean value greater than that of the liver, this reflected severe systemic disease.

Humans↗
PubMed2004

Comparison of Z-axis automatic tube current modulation technique with fixed tube current CT scanning of abdomen and pelvis.

PURPOSE: To compare image quality, diagnostic acceptability, and radiation exposure associated with 16-section multi-detector row computed tomographic (CT) examinations of abdomen and pelvis performed with z-axis modulation technique of automatic tube current modulation and with manual selection of fixed tube current. MATERIALS AND METHODS: Sixty-two consecutive subjects (mean age, 60 years; age range, 19-84 years; male-to-female ratio, 35:27) underwent follow-up CT of abdomen and pelvis with use of a 16-section multi-detector row scanner and z-axis modulation technique (10.5-12.0-HU noise index, 10-380 mA). Scanning parameters included 140 kVp, 0.5-1.0-second gantry rotation time, 0.938:1 beam pitch, and 5-mm reconstructed section thickness. For each subject, images obtained with z-axis modulation were compared with previous images obtained with fixed tube current (200-300 mA) and with other parameters identical. Images were compared for noise and diagnostic acceptability by two subspecialty radiologists using a five-point scale (1, unacceptable; 3, acceptable; 5, excellent) at five levels: upper liver at diaphragm, porta hepatis, right kidney hilum, iliac crest, and upper margin of acetabulum. Tube current and gantry rotation time used for acquisitions at these levels were recorded. Data were analyzed with parametric and nonparametric statistical tests. RESULTS: Although no significant differences were found (P =.34), images acquired with z-axis modulation at the levels of the upper liver (diaphragm) and acetabulum had a higher noise and lower diagnostic quality, compared with images acquired with fixed tube current. Compared with fixed tube current, z-axis modulation resulted in tube current-time product reduction in 54 (87%) of 62 examinations (mean reduction, 71.2 mAs) and increase in eight (13%) (mean increase, 17.0 mAs). CONCLUSION: Compared with manually selected fixed tube current, z-axis automatic tube current modulation resulted in reduced tube current-time product and similar image noise and diagnostic acceptability at CT of abdomen and pelvis.

Abdominal Neoplasms↗
PubMed1988

Sclerosing peritonitis. Possible early diagnosis by computerized tomography of the abdomen.

Sclerosing peritonitis (SP) has come to be recognized as a serious complication of peritoneal dialysis (PD). However, diagnosis is often established at a late stage of the disease and at laparotomy. The use of computerized tomography (CT) of the abdomen in 2 patients, clinically suspected of suffering from SP, revealed loculated ascites, adherent bowel loops, bowel lumenal narrowing, and thickening of the peritoneal membrane. Such radiological changes in patients on PD seem highly consistent with a diagnosis of SP. We feel that CT of the abdomen may help in attaining an early, correct, and noninvasive diagnosis of SP. We recommend that CT of the abdomen be performed in any patient on chronic PD who has clinical manifestations suggestive of SP. Early diagnosis of SP can lead to early cessation of PD and hopeful recovery of the peritoneal membranes and space.

Female↗
PubMed1992

Venous air embolism in prone dogs positioned with the abdomen hanging freely: percentage of gas retrieved and success rate of resuscitation.

Based on reports of fatal venous air embolism (VAE) occurring during lumbar laminectomy and spinal fusion in prone patients positioned with the abdomen hanging freely, it has been recommended that monitoring for VAE should be used for such cases and that a multiorificed central venous catheter should be inserted for aspiration of VAE. The present study was designed to examine aspiration of VAE when prone dogs positioned with the abdomen hanging freely were given a fatal VAE via a femoral vein. Twenty-one dogs were anesthetized with halothane and nitrous oxide in oxygen and positioned with the abdomen ventral and hanging freely, the head fixed in a stereotaxic frame, the upper extremities resting on a surface approximately 10 cm below the level of the stereotaxic frame, and the lower extremities on a surface below the level of the upper extremities (to ensure that VAE entering the inferior vena cava would ascend toward the heart). In the control group (n = 7), a central catheter was placed but was not used to aspirate VAE. In a second group (n = 7), a Cook Bunegin-Albin multiorificed catheter was inserted; and in a third group (n = 7), an American Edwards 7F Swan-Ganz catheter was inserted. Dogs were then given a predetermined lethal dose of air (5 mL/kg) over 30 s via the femoral vein. In groups 2 and 3, attempts to aspirate VAE were begun with the first decrease in expired CO2. The amounts of gas retrieved (expressed as a percent of the injected air) and the incidence of successful resuscitation were compared.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

The twisted gene encodes Drosophila protein O-mannosyltransferase 2 and genetically interacts with the rotated abdomen gene encoding Drosophila protein O-mannosyltransferase 1.

The family of mammalian O-mannosyltransferases includes two enzymes, POMT1 and POMT2, which are thought to be essential for muscle and neural development. Similar to mammalian organisms, Drosophila has two O-mannosyltransferase genes, rotated abdomen (rt) and DmPOMT2, encoding proteins with high homology to their mammalian counterparts. The previously reported mutant phenotype of the rt gene includes a clockwise rotation of the abdomen and defects in embryonic muscle development. No mutants have been described so far for the DmPOMT2 locus. In this study, we determined that the mutation in the twisted (tw) locus, tw(1), corresponds to a DmPOMT2 mutant. The twisted alleles represent a complementation group of recessive mutations that, similar to the rt mutants, exhibit a clockwise abdomen rotation phenotype. Several tw alleles were isolated in the past; however, none of them was molecularly characterized. We used an expression rescue approach to confirm that tw locus represents DmPOMT2 gene. We found that the tw1 allele represents an amino acid substitution within the conserved PMT domain of DmPOMT2 (TW) protein. Immunostaining experiments revealed that the protein products of both rt and tw genes colocalize within Drosophila cells where they reside in the ER subcellular compartment. In situ hybridization analysis showed that both genes have essentially overlapping patterns of expression throughout most of embryogenesis (stages 8-17), while only the rt transcript is present at early embryonic stages (5 and 6), suggesting its maternal origin. Finally, we analyzed the genetic interactions between rt and tw using several mutant alleles, RNAi, and ectopic expression approaches. Our data suggest that the two Drosophila O-mannosyltransferase genes, rt and tw, have nonredundant functions within the same developmental cascade and that their activities are required simultaneously for possibly the same biochemical process. Our results establish the possibility of using Drosophila as a model system for studying molecular and genetic mechanisms of protein O-mannosylation during development.

Amino Acid Sequence↗
PubMed1975

A radiologic study of tuberculosis of the abdomen (gastrointestinal tract).

The roentgenologic features of 160 cases of tuberculosis of the abdomen are reviewed. The 3 standard examinations of the gastrointestinal tract (plain film abdominal roentgenography, barium meal and follow-through studies, and barium enema examinations) are required to provide useful pointers towards the diagnosis. In plain film roentgenography of the abdomen, the triad of ascites, absence of gas shadows in the right iliac fossa, and segmental dilatation of the terminal ileum demonstrates features which are very suspicious of intestinal tuberculosis. In the barium meal studies showing disordered small bowel patterns, tuberculosis of the abdomen should be considered when this pattern is associated with fixation of bowel loops on supine and erect roentgenograms, spiculation and the presence of multiple strictures in the small bowel. Although the duodenojejunal and ileocecal regions are the commonest sites involved, lesions are not confined to these sites alone, but may also involve any part of the alimentary canal such as the esophagus and the small and large bowel. However, no anorectal lesions were encountered in this study.

Ascites↗
PubMed1992

Primary malignant small round cell tumor of the abdomen: CT findings in five cases.

Malignant small round cell tumor of the abdomen is a newly described clinicopathologic entity. The features of this entity include a predilection for young men, predominant abdominopelvic location, and aggressive behavior. Pathologic analysis demonstrates a small-cell tumor unusually coexpressing desmin and keratin. This study describes CT characteristics in five patients with malignant small round cell tumor of the abdomen. All patients were young white men, 20-36 years old (mean, 28 years). In all five cases, CT scans revealed lobulated masses appearing to arise primarily from peritoneal surfaces and predominantly involving the peritoneal cavity of the abdomen (two cases) and pelvis (two cases); diffuse abdominopelvic involvement was noted in one case. The masses were centrally necrotic and enhanced inhomogeneously after administration of iodinated contrast material. Additional CT features included ascites (one case), calcifications in the dominant mass (one case), omental implants (two cases), hydronephrosis (four cases), anterior diaphragmatic lymphadenopathy (two cases), liver metastases (two cases), and retroperitoneal lymphadenopathy (two cases). CT findings of abdominal malignant small round cell tumor are nonspecific and mimic findings noted in other conditions, such as peritoneal carcinomatosis and leiomyosarcomatosis.

Abdominal Neoplasms↗
PubMed1995

Use of contrast material for spiral CT of the abdomen: comparison of hepatic enhancement and vascular attenuation for three different contrast media at two different delay times.

OBJECTIVE: The purpose of this study was to determine the relative effects of delay time, contrast agent concentration, and contrast agent volume on hepatic enhancement and on aortic and portal vein attenuation for contrast-enhanced spiral CT of the abdomen. The effect of delay time was evaluated by comparing two different delay times for each of three IV contrast media. Three different media were tested to identify whether the effects were different with different iodine concentrations and doses or with different volumes of contrast medium. SUBJECTS AND METHODS: A total of 169 patients who underwent contrast-enhanced CT of the abdomen with spiral CT imaging were evaluated for enhancement of the liver parenchyma and for postenhancement attenuation of the aorta and portal vein. Total iodine doses of 30 g as 100 ml of iohexol 300 or 125 ml of ioversol 240 and of 40 g as 125 ml of ioversol 320 were evaluated at delay times of 45 and 60 sec and with a low-flow monophasic injection at a rate of 2 ml/sec. RESULTS: For each contrast medium tested, a 60-sec delay provided greater hepatic enhancement than did a 45-sec delay (43 vs 32 H for iohexol 300, 37 vs 28 H for ioversol 240, and 50 vs 39 H for ioversol 320; all comparisons, p < or = .0001). The aortic attenuation achieved in the abdomen after contrast medium administration was significantly greater with a 45-sec delay than with a 60-sec delay for iohexol 300 (p = .0290) but not for the other contrast media. The portal vein attenuation achieved after contrast medium administration was significantly greater with a 60-sec delay than with a 45-sec delay for all three contrast media (p = .0051). CONCLUSION: When IV contrast material was injected with a low-flow-rate monophasic bolus, a delay time of 60 sec, longer than that typically used for dynamic incremental scanning, provided greater hepatic enhancement in spiral CT. This result was significant for the three contrast media tested. Aortic attenuation was significantly greater at shorter delay times when a smaller volume of contrast material was injected. Portal vein attenuation was greater at longer delay times, suggesting that the optimal delay time may be longer than 60 sec. Further work to determine the optimal scanning window for hepatic enhancement in spiral CT by use of time-density curves is indicated.

Analysis of Variance↗
PubMed1996

Comparison of tailored and empiric scan delays for CT angiography of the abdomen.

OBJECTIVE: Scan delays for CT angiography of the abdomen are currently individualized by matching a scan delay to the transit time of a test bolus of IV contrast material to the abdominal aorta. We sought to determine whether this procedure improves the extent and uniformity of aortic enhancement when compared with the use of a standard scan delay that is determined empirically. SUBJECTS AND METHODS: CT angiography of the upper abdomen (either the entire abdominal aorta or the aorta spanning the length of both kidneys for dedicated renal studies) was obtained in 48 patients who were considered to have normal cardiac function as determined by their referring physicians. Patients were randomized to undergo CT angiography that used either a standard scan delay of 20 or 22 sec (group 1, n = 26) or a tailored scan delay (group 2, n = 22), all other imaging parameters being identical. Tailored delays were determined by measuring contrast transit time to the abdominal aorta with software from the SmartPrep system. For each patient, aortic attenuation was measured at three different anatomic levels, and a lower threshold of 160 H was considered optimal. The number of attenuation values above this threshold, the mean attenuation, and the attenuation changes for each unit length along the abdominal aorta were then compared for the two groups of patients. RESULTS: Fifty-eight (74%) of 78 aortic attenuation values in group 1 and 55 (88%) of 69 in group 2 were above 160 H. Mean attenuation values were 192.2 H +/- 8.1 (+/-SE) in group 1 and 199.2 H +/- 10.1 in group 2. These values and the attenuation changes for each unit length along the abdominal aorta-3.7 H/cm +/- 1.7 for group 1 and 2.2 H/cm +/- 2.0 for group 2- were not significantly different. CONCLUSION: Tailoring the scan delay for CT angiography of the abdomen in patients considered to have normal cardiac function requires additional IV contrast agent, time, and patient imaging and does not improve the extent or uniformity of aortic enhancement over that obtained with a standard, empiric scan delay.

Angiography↗