Preoperative anthropomorphic radiographic measurements can predict postoperative pancreatic fistula formation following pancreatoduodenectomy

BACKGROUND

Postoperative pancreatic fistulae (POPF) are a major contributing factor to pancreatoduodenectomy-associated morbidity. Established risk calculators mostly rely on subjective or intraoperative assessments. We hypothesized that various objective preoperatively determined computed tomography (CT) measurements could predict POPF as well as validated models and allow for more informed operative consent in high-risk patients.

METHODS

Patients undergoing elective pancreatoduodenectomies between January 2013 and April 2018 were identified in a prospective database. Comparative statistical analyses and multivariable logistic regression models were generated to predict POPF development. Model performance was tested with receiver operating characteristics (ROC) curves. Pancreatic neck attenuation (Hounsfield units) was measured in triplicate by pancreatic protocol CT (venous phase, coronal plane) anterior to the portal vein. A pancreatic density index (PDI) was created to adjust for differences in contrast timing by dividing the mean of these measurements by the portal vein attenuation. Total areas of subcutaneous fat and skeletal muscle were calculated at the L3 vertebral level on axial CT. Pancreatic duct (PD) diameter was determined by CT.

RESULTS

In the study period 220 patients had elective pancreatoduodenectomies with 35 (16%) developing a POPF of any grade. Multivariable regression analysis revealed that demographics (age, sex, and race) were not associated with POPF, yet patients resected for pancreatic adenocarcinoma or chronic pancreatitis were less likely to develop a POPF (10 vs. 24%; p = 0.004). ROC curves were created using various combinations of gland texture, body mass index, skeletal muscle index, sarcopenia, PDI, PD diameter, and subcutaneous fat area indexed for height (SFI). A model replacing gland texture with SFI and PDI (AUC 0.844) had similar predictive performance as the established model (p = 0.169).

CONCLUSION

A combination of preoperative objective CT measurements can adequately predict POPF and is comparable to established models relying on subjective intraoperative variables. Validation in a larger dataset would allow for better preoperative stratification of high-risk patients and improve informed consent among this patient population.

Diffusion-weighted MRI as a screening tool for hepatocellular carcinoma in cirrhotic livers: correlation with explant data-a pilot study

OBJECTIVE

The purpose of this study was to compare the sensitivity and specificity of diffusion-weighted liver MRI alone with complete, multiphasic gadoteridol-enhanced MRI for the detection of hepatocellular carcinoma in cirrhotic patients before liver transplant.

MATERIALS AND METHODS

This single institution retrospective study was performed after IRB approval and was HIPAA compliant. MRI scans of 37 patients who underwent liver transplant were evaluated and findings correlated with liver explant (36) or biopsy (1). All MRI scans were obtained within six months of explant. MRI from 17 patients with liver lesions by report at imaging subsequently proven to be HCC at pathology and 20 controls without liver lesions by imaging and pathology were reviewed in random order on the radiology PACS by three independent readers blinded to the MRI reports and pathology reports in two separate sittings. First, only the diffusion-weighted images (DWI) were interpreted. Second, the complete multiphasic MRI exam with DWI was reviewed. A consensus read was obtained by two separate radiologists who had access to the patients' explant data in order to map lesions. Reader-specific and pooled classification was assessed using sensitivity, specificity, positive predictive value, and negative predictive values and corresponding 95% confidence intervals (CI) for both DWI and complete MRI examination readings compared to pathology. McNemar's test and Kappa coefficient were used to assess differences (agreement) in DWI and complete examination readings.

RESULTS

A total of 37 patients have been studied (25M 12F age range 21-70). Averaged results of the three independent readers demonstrated a sensitivity of 78% (95% CI 65-89%) and specificity of 88% (95% CI 77-95%) for DWI alone for detection of liver lesions, with a positive predictive value of 85% (95% CI 72-94%) and a negative predictive value of 83% (95% CI 71-91%). Review of the complete MRI exam showed a sensitivity of 90% (95% CI 76-97%) and a specificity of 82% (95% CI 66-92%) with a positive predictive value of 83% (95% CI 69-93%) and a negative predictive value of 89% (95% CI 74-97%). McNemar's agreement test revealed no significant difference between the DWI and complete multiphasic interpretations (p = 0.3458), with simple Kappa coefficient of 0.6716 (95% CI 0.5332-0.8110). Lesions identified on DWI ranged in size from 1.5 to 5 cm. Detection of lesions was decreased in the presence of artifact from motion, large ascites, and technical issues.

CONCLUSION

Diffusion-weighted MRI has NPV and PPV comparable to complete multiphasic MRI examination for liver lesion detection in cirrhotic patients and may have a role in screening.

Single-source dual-energy spectral multidetector CT of pancreatic adenocarcinoma: optimization of energy level viewing significantly increases lesion contrast

AIM

To evaluate lesion contrast in pancreatic adenocarcinoma patients using spectral multidetector computed tomography (MDCT) analysis.

MATERIALS AND METHODS

The present institutional review board-approved, Health Insurance Portability and Accountability Act of 1996 (HIPAA)-compliant retrospective study evaluated 64 consecutive adults with pancreatic adenocarcinoma examined using a standardized, multiphasic protocol on a single-source, dual-energy MDCT system. Pancreatic phase images (35 s) were acquired in dual-energy mode; unenhanced and portal venous phases used standard MDCT. Lesion contrast was evaluated on an independent workstation using dual-energy analysis software, comparing tumour to non-tumoural pancreas attenuation (HU) differences and tumour diameter at three energy levels: 70 keV; individual subject-optimized viewing energy level (based on the maximum contrast-to-noise ratio, CNR); and 45 keV. The image noise was measured for the same three energies. Differences in lesion contrast, diameter, and noise between the different energy levels were analysed using analysis of variance (ANOVA). Quantitative differences in contrast gain between 70 keV and CNR-optimized viewing energies, and between CNR-optimized and 45 keV were compared using the paired t-test.

RESULTS

Thirty-four women and 30 men (mean age 68 years) had a mean tumour diameter of 3.6 cm. The median optimized energy level was 50 keV (range 40-77). The mean ± SD lesion contrast values (non-tumoural pancreas - tumour attenuation) were: 57 ± 29, 115 ± 70, and 146 ± 74 HU (p = 0.0005); the lengths of the tumours were: 3.6, 3.3, and 3.1 cm, respectively (p = 0.026); and the contrast to noise ratios were: 24 ± 7, 39 ± 12, and 59 ± 17 (p = 0.0005) for 70 keV, the optimized energy level, and 45 keV, respectively. For individuals, the mean ± SD contrast gain from 70 keV to the optimized energy level was 59 ± 45 HU; and the mean ± SD contrast gain from the optimized energy level to 45 keV was 31 ± 25 HU (p = 0.007).

CONCLUSION

Significantly increased pancreatic lesion contrast was noted at lower viewing energies using spectral MDCT. Individual patient CNR-optimized energy level images have the potential to improve lesion conspicuity.

Placement of PEG tubes through previously placed self-expanding esophageal metal stents

BACKGROUND

Self-expanding metal stents are frequently used to palliate patients with malignant dysphagia and close tracheoesophageal fistulae. Despite proper stent positioning and deployment, in a subset of patients there is no improvement in dysphagia, closure of tracheoesophageal fistulae, or resolution of anorexia. Such patients may require a PEG tube. It has been suggested that PEG placement through a preexisting esophageal stent is problematic because of the risks of gastrostomy tube impaction within the stent and resultant stent migration.

METHODS

Case records were retrospectively reviewed of 9 consecutive patients with indwelling esophageal self-expanding metal stents undergoing attempted PEG.

OBSERVATIONS

PEG tube placement was successful in all patients. In 1 patient, the stent migrated distally into the stomach during PEG placement. This was managed endoscopically without further complication.

CONCLUSIONS

PEG placement in patients with previously placed esophageal self-expanding metal stents is a relatively safe and feasible procedure, although stent migration may occur.

Advantages of in situ hybridisation over direct or indirect in situ reverse transcriptase-polymerase chain reaction for localisation of galanin mRNA expression in rat small intestine and pituitary

In situ hybridisation (ISH) and direct or indirect in situ reverse transcriptase-polymerase chain reaction (RT-PCR) were used to detect galanin mRNA in paraffin sections of rat intestine and pituitary. With conventional ISH, a subset of intestinal neuronal ganglion cells and anterior pituitary endocrine cells were labelled. Direct in situ RT-PCR also labelled some cells in pituitary but not in intestine. Negative controls were unlabelled, but sections with 3' primer alone for RT-PCR appeared positive. No signal was apparent using the indirect in situ RT-PCR method. Investigation of the specificity of solution phase RT-PCR using RNA extracts from pituitary or intestine revealed that additional PCR products were detected under some conditions. The sequences of these PCR products suggested that one was the result of mispriming and single primer PCR, which could also have occurred in situ. Alternative galanin primers gave only the predicted RT-PCR product in solution phase yet still gave artefacts in tissue sections using direct in situ RT-PCR. ISH with probes transcribed from the correct PCR product gave identical labelling to the original galanin riboprobe. In conclusion, direct in situ RT-PCR is unreliable and requires validation, while indirect in situ RT-PCR may fail even though sufficient target exists for detection with conventional sensitive riboprobe ISH.

Role of ERCP in asymptomatic orthotopic liver transplant patients with abnormal liver enzymes

OBJECTIVE

The safety and efficacy of endoscopic retrograde cholangiopancreatography (ERCP) in the evaluation and management of biliary tract complications after orthotopic liver transplantation (OLT) have been previously demonstrated. However, the role of ERCP in evaluating asymptomatic OLT patients with abnormal liver enzymes with a previously normal biliary tree remains poorly defined. We sought to assess the utility of ERCP in this subset of patients.

METHODS

A retrospective analysis of-asymptomatic OLT patients with abnormal liver enzymes evaluated by ERCP was undertaken. In addition to ERCP, all these patients had a diagnostic abdominal Doppler ultrasound, and a percutaneous liver biopsy. All patients had choledochocholedochostomy at the time of transplant and normal T-tube cholangiograms 3 months postoperatively. A radiologist, blinded to clinical findings, interpreted the ultrasound as normal, biliary dilation, or vascular abnormalities. The same radiologist interpreted ERCP findings. A pathologist, blinded to clinical findings, graded liver biopsies as normal, diagnostic, or abnormal but nondiagnostic.

RESULTS

Twenty-two patients underwent 23 ERCPs. Twenty-two of the 23 ERCPs were normal (96%), and one abnormal ERCP finding did not explain the liver enzyme abnormality. Liver biopsy was diagnostic in 13 of 22 (57%) and in each case the ERCP was normal. The remaining 10 liver biopsies were abnormal but nondiagnostic. Ultrasound was abnormal in five of 22 cases, but in the three cases suggesting biliary dilation, the ERCP was interpreted as normal.

CONCLUSION

Routine use of ERCP in evaluation of asymptomatic OLT patients with liver function test abnormalities and normal cholangiograms at 3 months was not diagnostically useful. In this subset of patients, liver biopsy was usually abnormal and frequently diagnostic and should be the initial invasive diagnostic procedure.

CT cystography: radiographic and clinical predictors of bladder rupture

OBJECTIVE

Our goal was to identify radiographic and clinical variables that correlate with bladder rupture that may then be used as selection criteria for CT cystography in trauma patients.

SUBJECTS AND METHODS

Hemodynamically stable trauma patients with hematuria were examined under standardized protocol with dynamic oral and i.v. contrast-enhanced CT of the abdomen and pelvis, followed immediately by CT cystography. CT cystography consisted of contiguous 5-mm axial scans of the pelvis after retrograde distention of bladder with 300-400 ml of 4% iodinated contrast material. Radiographic and clinical variables (pelvic fracture, pelvic fluid, intraabdominal visceral injury, degree of hematuria, hematocrit, units of blood transfused, base deficit, injury mechanism, seat belt use, sex, age) were assessed and statistically analyzed using the two-tailed Fisher's exact test and Wilcoxon's rank sum test. Positive and negative individual and multivariate predictors were analyzed.

RESULTS

Of the 157 patients entered in our study, 12 (eight males and four females) had bladder rupture. One or more pelvic fractures were present in nine (75%) of the 12 patients (p < 0.001). Pubic symphysis diastasis, sacroiliac diastasis, and sacral, iliac, and pubic rami fractures were statistically associated with bladder rupture. Isolated acetabular fractures did not correlate with rupture. Eight (67%) of the 12 patients with bladder rupture revealed on CT cystography had gross hematuria (p < 0.001). No ruptures were seen in patients with <25 RBC/HPF (red blood cells per high-power field). All patients with rupture had pelvic fluid revealed on standard contrast-enhanced CT (p < 0.001).

CONCLUSION

Gross hematuria, pelvic fluid, and specific pelvic fractures were highly correlated with bladder rupture; identification of these findings may help in selection of trauma patients for CT cystography.

Pancreas divisum: implications for diagnostic and therapeutic pancreatography

OBJECTIVE

The purpose of our study was to determine the prevalence, distribution, and clinical significance of pancreatic ductal changes due to pancreatitis on ERCP in patients with pancreas divisum.

MATERIALS AND METHODS

From January 1993 through December 1997, 1714 patients underwent 2469 ERCP studies. Ninety-four patients (5.5%) had pancreas divisum. Retrospective review of the spot radiographs was performed to establish the presence and location of pancreatitis. Clinical indications for and therapy during ERCP were correlated with radiographic findings.

RESULTS

Of the 94 patients with pancreas divisum, 54 (57%) had radiographic evidence of pancreatitis. Of these 54 patients, 44 had at least one episode of clinically documented pancreatitis, seven had recurrent abdominal pain, and three underwent ERCP for biliary indications. In 76% of the 54 patients with radiographic evidence of pancreatitis, only the dorsal system showed irreversible inflammatory change (p < .0001). Acute recurrent pancreatitis was the most common indication for ERCP in divisum patients and was statistically more common than in pancreatitis patients with normal anatomy (p < .0001). Sixty-two (66%) of the 94 patients with pancreas divisum underwent endoscopic pancreatic intervention, most commonly minor papilla sphincterotomy or stenting or both. Eleven patients with clinically documented pancreatitis had no abnormalities revealed by ERCP.

CONCLUSION

In our population of patients referred for ERCP and found to have pancreas divisum, the prevalence of pancreatitis was very high and usually was limited to a dorsal distribution.

Stenotrophomonas (Xanthomonas) maltophilia infection in necrotizing pancreatitis

CONCLUSION

Although the therapy of infected pancreatic collections or organized pancreatic necrosis remains surgical, we have demonstrated that infected organized pancreatic necrosis can be treated endoscopically.

BACKGROUND

Stenotrophomonas (Xanthomonas) maltophilia has been increasingly recognized as a nosocomial pathogen associated with meningitis, pneumonia, conjunctivitis, soft tissue infections, endocarditis, and urinary tract infections. This organism is consistently resistant to imipenem, a drug commonly employed in patients with necrotizing pancreatitis to prevent local and systemic infections.

METHODS AND RESULTS

We report the first case of infected pancreatic necrosis by S. (X.) maltophilia. Our patient was treated successfully with endoscopic drainage of the pancreatic fluid collection and appropriate antibiogram-based antibiotic therapy. Endoscopic drainage has emerged as one of the treatment modalities for pancreatic fluid collections.

Comparison of two barium suspensions for dedicated small-bowel series

OBJECTIVE

The in vivo radiographic features of two commercially available formulations of barium used as contrast media in dedicated small-bowel series were compared.

SUBJECTS AND METHODS

Fifty-six consecutive outpatients referred for a dedicated small-bowel series were randomly administered either E-Z-Paque or Entrobar. Representative survey radiographs from each examination were randomized and reviewed by six gastrointestinal radiologists from three institutions. Each observer assigned a numeric score (1 = poor, 2 = fair, 3 = good, and 4 = excellent) that rated the quality of the radiograph with respect to these characteristics: definition of fold pattern, translucency, distention, and integrity of the barium column. Statistical analysis was performed for each characteristic using Wilcoxon's two-sample rank sum test.

RESULTS

All six observers found a statistically significant difference between the two barium formulations for mean scores for definition of fold pattern and translucency. Mean scores for fold pattern were 3.3, 3.0, 3.2, 3.6, 3.3, and 3.4 for Entrobar and 2.1, 2.3, 2.4, 3.2, 2.6, and 2.7 for E-Z-Paque. Mean scores for translucency were 2.5, 2.7, 2.8, 3.1, 2.7, and 3.3 for Entrobar and 1.6, 1.7, 2.1, 2.3, 1.9, and 2.7 for E-Z-Paque. No statistically significant difference was found for mean score for distention or integrity of the barium column.

CONCLUSION

On radiographs, Entrobar was found to have superior characteristics for visualization of fold pattern and translucency but offered no advantages for distention or integrity of the barium column. Improved translucency and definition of fold pattern may translate into improved sensitivity and confidence in diagnosing small-bowel abnormality.

Hemodialysis access graft stenosis: US detection

PURPOSE

To prospectively evaluate the sensitivity of ultrasonography (US) in diagnosing stenosis of hemodialysis access grafts and their drainage veins in patients clinically suspected of having graft dysfunction.

MATERIALS AND METHODS

Thirty-eight patients in whom dysfunction of their hemodialysis access grafts was suspected underwent both Doppler US and angiography. Gray-scale and color US were combined with spectral analysis of the graft, anastomoses, and venous outflow. Flow velocity at anastomoses and suspected stenotic areas was measured. The volume of flow in the graft was also measured. The prospective US criterion for diagnosis of stenosis was a focal twofold or higher elevation of peak systolic velocity (PSV) compared with the PSV immediately upstream. A blinded angiographic evaluation of the graft and drainage veins followed US. Angiographic diagnosis of stenosis required at least 50% narrowing in luminal diameter. US and angiographic results were then compared.

RESULTS

Angiography allowed diagnosis of 43 stenoses in 34 patients. US depicted 92% (37 of 40) of these stenoses, with a 94% positive predictive value for any individual patient. Focal 2- to 2.9-times PSV elevation was associated with 75% or greater stenosis. Graft flow volume and resistive index change did not correlate with stenosis.

CONCLUSION

US reliably depicts stenoses of hemodialysis access grafts and drainage veins in a clinically selected population when PSV criteria are used.

Transmural drainage of pancreatic fluid collections without electrocautery using the Seldinger technique

BACKGROUND

Complications of endoscopic transmural drainage of pancreatic fluid collections arise from entry through the gastrointestinal wall. We describe transmural drainage of these collections using the Seldinger technique without electrocautery.

METHODS

From January 1995 to September 1997, we attempted endoscopic transmural drainage of 94 consecutive pancreatic fluid collections without EUS guidance (needle-knife entry in 51, Seldinger entry technique in 43). Success of entry and complications were compared.

RESULTS

Successful entry was achieved in 95.3% using the Seldinger technique and 92.1% using the needle-knife entry technique (p = NS). Complications of bleeding and perforation were seen in 4.6% of patients in the Seldinger group and 15.7% in the needle-knife entry group.

CONCLUSIONS

The Seldinger technique of endoscopic transmural drainage of pancreatic fluid collections appears effective and safer than entry using the needle-knife. Collections as small as 3 cm in diameter can be entered using the Seldinger technique without EUS guidance.

Hysterosalpingography with videofluoroscopy: effect on radiologic practice in an academic medical center

RATIONALE AND OBJECTIVES

The authors attempted to determine whether videotaping the fluoroscopic portion of hysterosalpingography would result in changed diagnoses or an increase in diagnostic confidence.

MATERIALS AND METHODS

Ninety-nine consecutive outpatients underwent routine hysterosalpingography. The fluoroscopic portion of the examination was captured on videotape. Two consecutive interpretations of each hysterosalpingogram were made by attending radiologists. First, spot radiographs were interpreted alone. Second, these images were viewed along with videofluoroscopy. Concordance of and confidence in findings for the two interpretations were assessed with the two-tailed Fisher exact test.

RESULTS

Interpretations of spot radiographs alone and with videofluoroscopy were in agreement in 92 of 99 uterine examinations and 164 of 198 tubal examinations. For uterine examinations classified as normal, interpretations of spot radiographs and videofluoroscopy were in agreement in 56 of 57 cases; there was no change in confidence with review of videofluoroscopic images. For uterine examinations interpreted as abnormal, agreement was noted in 36 of 42 cases (P = .04), and confidence increased with videofluoroscopy in 10 of 42 cases (P = .00001). With normal tubal findings, interpretations agreed in 94 of 118 cases, and confidence increased in 56 of 118 cases (P = .002). With abnormal tubal findings, interpretations agreed in 70 of 80 cases, and confidence increased in 20 of 80 cases (P = .002). When findings with and without videofluoroscopy were discordant, confidence was always higher after review of video-fluoroscopic images.

CONCLUSION

Review of videofluoroscopic images obtained during hysterosalpingography increases the accuracy and confidence of diagnoses compared with review of spot radiographs alone.

Practical imaging in acute pancreatitis

Pancreatitis may be acute or chronic, mild or severe. In patients with acute pancreatitis the optimal imaging test is dynamic intravenous and oral contrast enhanced computed tomography (CECT). Serial CECTs are useful to monitor disease progression and to assess intraabdominal complications in patients with severe acute pancreatitis. CECT is helpful in planning the approach (endoscopic transmural versus percutaneous) for pancreatic drainage. Computed tomography or ultrasound-guided aspiration of pancreatic collections is safe, sensitive, and specific and has become a routine procedure used to screen for infected necrosis. When pancreatic drainage is contemplated, magnetic resonance imaging is useful for identifying residual necrotic debris within the collection. Patients with mild acute pancreatitis usually require no cross-sectional imaging study other than ultrasound screening for gallstones, if gallstone pancreatitis is suspected clinically. In patients with chronic pancreatitis, screening for complications such as superimposed acute pancreatitis or development of pancreatic pseudocysts may be performed with CECT or ultrasound.

Pancreatic fluid collections: diagnosis and endoscopic management

Pancreatitis may be acute or chronic, mild or severe. Acute necrotizing pancreatitis remains the most serious form of acute pancreatitis and accounts for the majority of complications. Although there is an established nomenclature for pancreatitis and pancreatic fluid collections, such as pancreatic pseudocysts, it is not widely understood or recognized by gastroenterologists. Because the management options for the treatment of pancreatic fluid collections continues to evolve with an increased use of endoscopic therapy, gastroenterologists will be increasingly called on to treat patients with pancreatitis and its complications. This article addresses and summarizes pancreatic fluid collections and their management, with an emphasis on endoscopic drainage.

Palliation of malignant gastric and small intestinal strictures with self-expandable metal stents

BACKGROUND

Malignant gastrointestinal obstruction is a common preterminal event that is often treated surgically. The use of self-expandable stents to treat malignant gastric and small intestinal strictures is limited. We evaluated the feasibility, effectiveness, safety and outcome of self-expandable metal stents in providing palliative care for patients with inoperable malignant strictures of the stomach and small intestine.

METHODS

Eleven consecutive patients with complete or near complete gastric or small intestinal obstruction were treated palliatively with self-expandable metal stents. Contrast radiographs were taken before and after insertion in all patients to confirm patency. Nineteen stents were placed using biliary guidewires and catheters under endoscopic and fluoroscopic guidance. Diets were modified as needed. Success was defined both technically and clinically.

RESULTS

Technical and clinical success with improvement in the patient's oral diet was achieved in ten patients (91%). The one failure was caused by severe anastomotic angulation and distal luminal obstruction. During the follow-up of 5 to 294 days (mean 77 days) there were no major complications except that the stents occluded in four patients.

CONCLUSION

Palliation of malignant gastric and small intestinal strictures with self-expandable metal stents is a feasible, effective, and safe alternative to operation.

The diagnosis and management of fluid collections associated with pancreatitis

Pancreatitis may be acute or chronic, mild or severe. Acute necrotizing pancreatitis remains the most serious form of acute pancreatitis and accounts for the majority of complications. Although there is an established nomenclature for pancreatitis and pancreatic fluid collections, such as pancreatic pseudocysts, it is not widely understood or recognized by physicians, including gastroenterologists. Because nonspecialists will be increasingly called upon to treat and appropriately refer patients with pancreatitis and its complications for more specialized care, it is important to understand the evolving treatment options for managing these patients. This article addresses and summarizes pancreatitis and its complications, particularly pancreatic collections.

Pancreatic fluid collections prior to intervention: evaluation with MR imaging compared with CT and US

PURPOSE

To evaluate the ability of magnetic resonance (MR) imaging to depict solid debris within pancreatic collections prior to intervention and to help assess drainability, as well as to compare MR findings with those obtained at computed tomography (CT) and ultrasound (US).

MATERIALS AND METHODS

Nineteen collections in 18 patients were evaluated with MR imaging, CT, and US prior to drainage. Prospective, blinded interpretations of imaging studies by three independent readers (each interpreted all the images obtained with only one modality) evaluated collection characteristics (debris, consistency, septation, wall thickness, and irregularity) and predicted drainability. Findings were compared with clinical diagnosis and clinical outcome of drainage.

RESULTS

MR imaging and CT depicted all collections; US failed to depict two collections. In nine patients with subacute necrotic collections, solid debris was seen in eight (89%) at MR imaging, in two (22%) at CT, and in eight (89%) at US. In seven patients with pseudocysts, debris was seen in two (28%) at MR imaging and in none at CT, as well as in six (100%) of six at US. A collection was defined as "not drainable" on the basis of the depiction of solid necrotic debris more than 1 cm in diameter. With this definition, statistically significant differences between sensitivity and specificity values, respectively, were found for the prediction of actual drainability: MR imaging, 100% and 100%; CT, 25% and 100%; US, 88% and 54%.

CONCLUSION

Predrainage MR imaging should be performed in patients with subacute pancreatic collections to avoid infectious complications from unrecognized necrotic debris that cannot be removed with use of standard pseudocyst drainage techniques.

Computed model of gadolinium enhanced MRI of breast disease

OBJECTIVE

Investigation has shown that the most useful MRI finding for the detection of breast cancer is enhancement following in travenous contrast. However, many widely different imaging protocols have been used. The purpose of this study is to explicate factors that affect the signal intensity of breast lesions after intravenous gadolinium.

METHODS AND MATERIALS

A computer model was developed using equations based on published data. The effect of gadolinium on breast tissues was calculated using the model with appropriate values for baseline tissue relaxation times, relaxivity of gadolinium at the given field strength and concentration of gadolinium based on published data, for the TR, TE, flip angle and field strength of several published sequences used for enhanced breast MRI.

RESULTS

The computer model allows comparison of the performance of different sequences, which can be displayed graphically. These vary in their performance, largely dependent on T1 weighting. Enhancement is also affected by the baseline of the T1 of the lesion and sensitivity of the sequence to gadolinium. Malignant lesions demonstrate greater observed enhancement than predicted when assuming symmetric distribution of contrast, indicating there is greater accumulation of gadolinium, accounting for the differential enhancement between benign and malignant lesions.

CONCLUSIONS

MRI sequences vary greatly in their demonstration of enhancement after intravenous gadolinium contrast. Numerical diagnostic criteria such as % signal intensity change must be interpreted with care when using a different sequence than that on which the criterion was developed. There is preferentially greater accumulation of contrast in malignant lesions, whether due to angiogenesis or altered permeability.

Treatment of colonic obstruction with expandable metal stents: radiologic features

OBJECTIVE

The purpose of this prospective study was to evaluate the efficacy of expandable metal stents for colonic decompression in patients presenting with acute malignant obstruction and to describe the associated radiographic findings.

SUBJECTS AND METHODS

Using both fluoroscopic and endoscopic guidance, we placed expandable metal stents within the colons of 13 patients presenting with acute malignant obstruction. Stents were placed in four patients to permit a standard bowel cleansing before surgical resection with primary anastomosis. In the other nine patients, stents were placed for palliation of nonresectable tumors, obviating colostomy. Outcomes and complications were analyzed. The radiologic aspects of procedural planning, stent placement, assessment after placement, and detection of complications were evaluated.

RESULTS

Of the four surgical candidates who were successfully resected with primary anastomosis, two received incomplete bowel cleansing because of stent migration with recurrent obstruction. Eight of the nine patients who had stents placed for palliation of nonresectable tumors had relief of acute obstruction. Complications in this group included two perforations, one that required immediate colostomy and one that was self-limited and conservatively treated. Two other patients of the eight developed early stent obstruction, requiring colostomy in one. The other patient who had a stent placed for palliation of a nonresectable tumor declined further treatment. Contrast-enhanced enema examination proved useful in assessing the suitability of lesions for stent decompression, directing the choice of stent type and the most appropriate position for the patient during the stent placement. Immediately after stent placement, plain abdominal radiographs and water-soluble contrast enema examinations helped us verify stent position and patency.

CONCLUSION

These results suggest that placement of expandable metal stents in patients presenting with acute, malignant colonic obstruction is a viable alternative to colostomy and can potentially decrease morbidity and mortality. Radiologic assessment before, during, and after stent placement plays an integral role in the management of patients undergoing stent decompression of the colon.

Endoscopic therapy for organized pancreatic necrosis

BACKGROUND & AIMS

The treatment of patients with extensive pancreatic necrosis remains controversial; a subpopulation of patients with extensive acute pancreatic necrosis develop complex, organized collections. This study examined the feasibility of endoscopic drainage in patients with extensive organized pancreatic necrosis.

METHODS

Eleven patients with organized pancreatic necrosis (8 sterile and 3 infected) after severe acute necrotizing pancreatitis underwent attempted endoscopic drainage. Dynamic contrast-enhanced computerized tomography showed > or = 50% pancreatic necrosis in 10 of 11 patients in whom endoscopic drainage was performed. In 8 patients, an intrapancreatic nasobiliary lavage catheter was placed into the collection concurrently with 10F stents.

RESULTS

Complete resolution was achieved nonoperatively in 9 patients. At a mean follow-up of 12 months, 1 patient developed a pseudocyst, which was successfully drained endoscopically. Complications occurred in 5, including bleeding that precluded entry into one collection.

CONCLUSIONS

Endoscopic therapy may be a viable management option for a subset of patients who remain symptomatic after an episode of acute pancreatic necrosis after the necrosis has become organized and partially liquefied. Intrapancreatic lavage catheter placement is essential to the success of this procedure. Further evaluation of this technique is needed before this method can be adopted into clinical practice.

Influencing prescribing practices and associated outcomes utilizing the drug use evaluation process

Influencing prescribing practices and the implementation of pharmaceutical care utilizing the drug use evaluation (DUE) process at a 891-bed teaching hospital are described. The DUE program has been structured to provide for significant pharmacy involvement while maintaining medical staff responsibility as outlined by the Joint Commission on Accreditation of Healthcare Organizations. A multidisciplinary approach is used to identify problems and develop prescribing criteria and educational initiatives. Pharmacists provide drug therapy monitoring and engage in clinical interventions and documentation of outcomes on a daily basis. DUE program pharmacists help target possible interventions, assure monitoring and outcome documentation, and compile results of all initiatives for reporting purposes to the medical staff and quality assessment program. Specific performance compliance and problems are identified and incorporated into the credentialing process. Corrective measures are determined by the Pharmacy and Therapeutics (P&T) Subcommittee with subsequent actions carried out by peer physicians. The net result is a positive influence on prescribing practices that improves the appropriate and effective use of drugs and improves patient outcomes.

Attitudes of healthcare professionals toward patient counseling on drug-nutrient interactions

OBJECTIVE

To evaluate the attitudes of healthcare providers on drug-nutrient interaction (DNI) counseling.

DESIGN

A mail survey.

SETTING

Random sample of healthcare providers with interest in nutrition, practicing in Iowa or Nebraska.

METHODS

A 48-item questionnaire was constructed on the basis of a review of DNI literature. The survey was sent to 100 pharmacists, 50 registered dietitians, 25 registered nurses, and 25 physicians identified from culled mailing lists of the American Society of Parenteral and Enteral Nutrition and the Iowa Nebraska Society of Parenteral and Enteral Nutrition. Assessed variables included the amount of DNI counseling provided, who is in the best position to provide DNI counseling, and what information should be included in instructional materials on DNIs for patients. Data were entered into a relational database for evaluation and comparison.

RESULTS

The usable response rate was 49.5 percent (n = 99): 49 pharmacists, 29 dietitians, 18 nurses, and 3 physicians. Only 12 respondents provided DNI counseling in > 50 percent of patient interactions. Seventy-one respondents (72 percent) felt pharmacists were in the best position to discuss DNIs with patients. More than half of the respondents felt a new DNI pamphlet should be developed to replace an existing Food and Drug Administration-sponsored pamphlet. Although 70 percent felt the new pamphlet should be organized according to specific drugs, many felt the format should also include specific populations and disease states. Eighty-six percent indicated that a chart on DNIs geared toward healthcare professionals would be useful.

CONCLUSIONS

Patient-oriented resources should be developed to enhance DNI counseling. Pharmacists are in a uniquely advantageous position to provide DNI counseling.

Sympathetic stimulation alters left ventricular relaxation and chamber size

Alterations in left ventricular (LV) contractility, relaxation, and chamber dimensions induced by efferent sympathetic nerve stimulation were investigated in nine anesthetized open-chest dogs in sinus rhythm. Supramaximal stimulation of acutely decentralized left stellate ganglia augmented heart rate, LV systolic pressure, and rate of LV pressure rise (maximum +dP/dt, 1,809 +/- 191 to 6,304 +/- 725 mmHg/s) and fall (maximum -dP/dt, -2,392 +/- 230 to -4,458 +/- 482 mmHg/s). It also reduced the time constant of isovolumic relaxation, tau (36.5 +/- 4.8 to 14.9 +/- 1.1 ms). Simultaneous two-dimensional echocardiography recorded reductions in end-diastolic and end-systolic LV cross-sectional chamber areas (23 and 31%, respectively), an increase in area ejection fraction (32%), and increases in end-diastolic and end-systolic wall thicknesses (14 and 13%, respectively). End-systolic and end-diastolic wall stresses were unchanged by stellate ganglion stimulation (98 +/- 12 to 95 +/- 9 dyn x 10(3)/cm2; 6.4 +/- 2.4 to 2.4 +/- 0.3 dyn x 10(3)/cm2, respectively). Atrial pacing to similar heart rates did not alter monitored indexes of contractility. Dobutamine and isoproterenol induced changes similar to those resulting from sympathetic neuronal stimulation. These data indicate that when the efferent sympathetic nervous system increases left ventricular contractility and relaxation, concomitant reductions in systolic and diastolic dimensions of that chamber occur that are associated with increasing wall thickness such that LV wall stress changes are minimized.

Gadolinium-enhanced MR imaging of renal masses

Preliminary reports indicate that gadolinium-enhanced magnetic resonance (MR) imaging is highly accurate for diagnosis of renal masses. The authors demonstrate the clinical utility of MR imaging for evaluating renal masses in 26 patients for whom contrast material-enhanced computed tomography (CT) was contraindicated or inadequate for diagnosis or staging. Nine patients had complex cysts, one had a perinephric hematoma, and 16 had a solid mass (three of which were benign). All patients underwent MR imaging before and after administration of gadopentetate dimeglumine. Multiple imaging techniques and sequences were used. All tumors and no cysts enhanced with gadolinium. Even though the three benign tumors enhanced, two were differentiated from renal carcinoma on the basis of other imaging features. Unenhanced MR imaging was accurate in staging of renal carcinomas, and use of gadolinium did not improve staging accuracy. Gadolinium-enhanced MR imaging is indicated when results of CT and sonography are indeterminate for malignancy and when contrast-enhanced CT is contraindicated because of renal failure or adverse reaction to iodinated contrast material. In this latter instance, MR imaging is useful for both diagnosis and staging.

Intrapulmonary teratoma: a case report and review of the literature

Intrapulmonary teratomas are rare; only 30 cases have been reported in the world literature. These tumors are thought to originate from the third pharyngeal pouch. They occur equally in men and women and usually are diagnosed in the second to fourth decade of life. They are more often benign than malignant, although malignant lesions may have a favorable postoperative prognosis and benign lesions may exhibit high morbidity and mortality because of their size and location. These tumors present radiographically as lobulated masses that may contain calcification or peripheral collections of air. They most often occur in the upper lobes. The computed tomographic findings of intrapulmonary teratoma are less well known but have been described in two cases. An additional case is presented with a review of the literature and a tabular summary of the characteristics of this unusual entity.

Auditory screening of infants

Within the last 20 years, infant hearing screening has progressed from a laudable goal to a state-mandated reality in many areas of the United States. The high risk register provides a means by which history and neonatal physical examination can be used to identify the infant at risk for hearing loss. Two procedures (crib-O-gram and auditory brainstem-evoked response) have been the most common methods of screening for hearing loss in the newborn or in intensive care nurseries. Evoked cochlear emissions reportedly are identifiable in 90 to 100% of normal-hearing infants. This observation has lead to the use of evoked otoacoustic emissions as a hearing screening procedure with infants.

Infective endocarditis, 1983-1988: echocardiographic findings and factors influencing morbidity and mortality

The echocardiograms and clinical records of 70 patients with infective endocarditis seen between 1983 and 1988 were examined to evaluate the role of two-dimensional and Doppler echocardiography in the diagnosis of infective endocarditis and identify risk factors for morbidity and mortality. A blinded observer reviewed the echocardiograms for the presence and size of vegetations and the severity of the valvular regurgitation. Vegetations were identified in 54 (78%) of 69 technically satisfactory echocardiograms. In 38 patients whose heart was examined at surgery or autopsy, all vegetations diagnosed by echocardiography were confirmed, but six additional vegetations were found. Abnormal (greater than or equal to 2+) valvular regurgitation was present in 88% of patients. No patient with less than or equal to 1+ regurgitation (n = 8) died or required valve surgery for heart failure, but three of the eight patients did undergo surgery for mycotic aneurysm, recurrent embolism or paravalvular abscess. In patients without embolism before echocardiography, there was a trend toward a greater incidence of subsequent embolism in those with vegetations greater than 10 mm in size (26% [8 of 31] compared with 11% [2 of 18] with vegetations less than or equal to 10 mm) (p = 0.19). By multivariate analysis, risk factors for in-hospital death (n = 7) were an infected prosthetic valve (p less than 0.007), systemic embolism (p less than 0.02) and infection with Staphylococcus aureus (p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of ventricular contractility indexes in the dog with left ventricular dysfunction induced by rapid atrial pacing

Eight dogs were studied by simultaneous invasive hemodynamic and two-dimensional echocardiographic methods to determine whether left ventricular contractility is altered by 2 weeks of rapid atrial pacing. Additionally, this study evaluated the response of three ventricular contractility indexes to both the pacing intervention and acute load alteration. The indexes compared were ejection fraction, peak systolic pressure to end-systolic volume index ratio (SBP/ESVI) and end-systolic wall stress to end-systolic volume index ratio (ESWS/ESVI). After 2 weeks of pacing at 265 +/- 20 min-1 (mean +/- SD), cardiac index and ejection fraction were reduced to 73 +/- 38 ml/kg per min and 22 +/- 6%, respectively, from 161 +/- 22 and 46 +/- 7 before pacing (both p less than 0.001). Concomitantly, SBP/ESVI and ESWS/ESVI were reduced to 34 +/- 10 mm Hg/ml per kg and 54 +/- 19 g/cm2 per ml per kg, respectively, from 84 +/- 29 and 121 +/- 36 before pacing (both p less than 0.005). There were high correlations for the changes in SBP/ESVI and ejection fraction (r = 0.94, p less than 0.001) and ESWS/ESVI and ejection fraction (r = 0.89, p less than 0.003). Acute afterload alteration with phenylephrine depressed ejection fraction but not SBP/ESVI or ESWS/ESVI. Therefore, this study demonstrates 1) that left ventricular contractility is markedly depressed in the dog by 2 weeks of rapid atrial pacing, and 2) that SBP/ESVI and ESWS/ESVI are superior to ejection fraction as ventricular contractility indexes because these ratios accurately measure contractility changes but are influenced less by after-load conditions.

Blood coagulation abnormalities in Fischer strain rats bearing tumors

This study reports an unusual subpopulation of rats bearing transplanted tumors approximately 50% of the total and apparently unrelated to the presence of metastases, that exhibited shortened bleeding times despite reduced platelet numbers and/or fibrinogen levels. The remaining rats exhibited the expected inverse relationships between bleeding time and platelet numbers and/or fibrinogen level. Tumors were hepatomas and squamous cell carcinomas initially induced in the Fischer strain of rats and carried by passage through tissue culture or syngenic recipient animals.

Auditory brain stem evoked response characteristics in developing infants

The auditory brain stem response (ABR) of a single group of developing normal infants was examined longitudinally, from newborn through 6 months of age. A sufficiently broad range of stimulus variables was included to ensure that the auditory system was adequately sampled in order to demonstrate developmental principles. Findings indicate that there are no differences in wave V latency-intensity functions between infants and adults. For waves I, III, and V, absolute and interwave latency-repetition rate functions differ between infants and adults and undergo systematic changes throughout the first 6 months of life. The most dramatic ABR changes (between any two sequential test sessions in infants) occurred between the ages of newborn and 2 weeks, with less pronounced ABR changes beyond 2 weeks of age. The pattern of latency change for wave I was different from that for waves III and V. After 2 weeks of age, wave I latency was the same as the adult value at all repetition rates. In contrast, waves III and V were characterized by decreasing latency throughout the follow-up period. A curvilinear developmental model provided a satisfactory fit to ABR latency data.

Auditory brain stem evoked response characteristics in the full-term newborn infant

The auditory brain stem response to click stimuli was investigated in a group of 50 full-term healthy newborns, as well as in a group of 20 older children and adults. The stimulus parameters of click level and click repetition rate were varied systematically to quantify the characteristics of the auditory brain stem response in the full-term newborn infant. The results reveal increased latencies for waves I, III, and V for all conditions among the newborns, relative to the older age group. The results suggest that the neurological system is the primary source of differences between newborns and older subjects, but do not rule out the possibility that external ear, middle ear, or cochlear mechanisms may also contribute to the differences observed.

Echocardiographic assessment of tricuspid regurgitation during ventricular demand pacing

Twenty patients from our pacemaker clinic population were assessed clinically and by saline contrast echocardiography (subxiphoid view) to determine the prevalence of tricuspid regurgitation (TR) and, if TR was present, its mechanism. The patients had no known TR before lead placement, a single transvenous right ventricular pacing lead present more than 6 months (mean 52, range 7 to 138), ventricular demand pacing alternating with sinus rhythm and rate programmability. Each patient was studied in sinus rhythm and during ventricular pacing. Using the criterion of inferior vena cava (IVC) contrast reflux during ventricular systole to diagnose TR, no patient had evidence of TR in sinus rhythm, consistent with clinical examination. During ventricular demand pacing, jugular venous pulse cannon A waves developed in 10 patients, and 18 patients (including these 10) had IVC contrast reflux during ventricular systole. Analysis of the timing of IVC reflux revealed its close temporal relation to the timing of atrial systole rather than a fixed timing during ventricular systole. This reflux occurred with loss of normal atrioventricular (AV) synchrony and the underlying mechanism in all cases was shown to be right atrial contraction against a closed tricuspid valve. Two patients who did not have such a pattern with pacing maintained normal AV synchrony. These observations indicate that: TR is an uncommon accompaniment of ventricular demand pacing; the jugular venous pulse and IVC echocardiographic contrast patterns during ventricular demand pacing simulate TR when AV asynchrony [corrected] occurs; and the IVC contrast pattern of pacing induced AV asynchrony [corrected] is best termed the cannon A wave synchronous pattern.

Effects of age and mild hearing loss on speech recognition in noise

Using an adaptive strategy, the effects of mild sensorineural hearing loss and adult listeners' chronological age on speech recognition in babble were evaluated. The signal-to-babble ratio required to achieve 50% recognition was measured for three speech materials presented at soft to loud conversational speech levels. Four groups of subjects were tested: (1) normal-hearing listeners less than 44 years of age, (2) subjects less than 44 years old with mild sensorineural hearing loss and excellent speech recognition in quiet, (3) normal-hearing listeners greater than 65 with normal hearing, and (4) subjects greater than 65 years old with mild hearing loss and excellent performance in quiet. Groups 1 and 3, and groups 2 and 4 were matched on the basis of pure-tone thresholds, and thresholds for each of the three speech materials presented in quiet. In addition, groups 1 and 2 were similar in terms of mean age and age range, as were groups 3 and 4. Differences in performance in noise as a function of age were observed for both normal-hearing and hearing-impaired listeners despite equivalent performance in quiet. Subjects with mild hearing loss performed significantly worse than their normal-hearing counterparts. These results and their implications are discussed.