Management and follow-up of gallbladder polyps: updated joint guidelines between the ESGAR, EAES, EFISDS and ESGE

Abstract

Main recommendations

Primary investigation of polypoid lesions of the gallbladder should be with abdominal ultrasound. Routine use of other imaging modalities is not recommended presently, but further research is needed. In centres with appropriate expertise and resources, alternative imaging modalities (such as contrast-enhanced and endoscopic ultrasound) may be useful to aid decision-making in difficult cases. Strong recommendation, low–moderate quality evidence.

Cholecystectomy is recommended in patients with polypoid lesions of the gallbladder measuring 10 mm or more, providing the patient is fit for, and accepts, surgery. Multidisciplinary discussion may be employed to assess perceived individual risk of malignancy. Strong recommendation, low-quality evidence.

Cholecystectomy is suggested for patients with a polypoid lesion and symptoms potentially attributable to the gallbladder if no alternative cause for the patient’s symptoms is demonstrated and the patient is fit for, and accepts, surgery. The patient should be counselled regarding the benefit of cholecystectomy versus the risk of persistent symptoms. Strong recommendation, low-quality evidence.

If the patient has a 6–9 mm polypoid lesion of the gallbladder and one or more risk factors for malignancy, cholecystectomy is recommended if the patient is fit for, and accepts, surgery. These risk factors are as follows: age more than 60 years, history of primary sclerosing cholangitis (PSC), Asian ethnicity, sessile polypoid lesion (including focal gallbladder wall thickening > 4 mm). Strong recommendation, low–moderate quality evidence.

If the patient has either no risk factors for malignancy and a gallbladder polypoid lesion of 6–9 mm, or risk factors for malignancy and a gallbladder polypoid lesion 5 mm or less, follow-up ultrasound of the gallbladder is recommended at 6 months, 1 year and 2 years. Follow-up should be discontinued after 2 years in the absence of growth. Moderate strength recommendation, moderate-quality evidence.

If the patient has no risk factors for malignancy, and a gallbladder polypoid lesion of 5 mm or less, follow-up is not required. Strong recommendation, moderate-quality evidence.

If during follow-up the gallbladder polypoid lesion grows to 10 mm, then cholecystectomy is advised. If the polypoid lesion grows by 2 mm or more within the 2-year follow-up period, then the current size of the polypoid lesion should be considered along with patient risk factors. Multidisciplinary discussion may be employed to decide whether continuation of monitoring, or cholecystectomy, is necessary. Moderate strength recommendation, moderate-quality evidence.

If during follow-up the gallbladder polypoid lesion disappears, then monitoring can be discontinued. Strong recommendation, moderate-quality evidence.

Source and scope

These guidelines are an update of the 2017 recommendations developed between the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), European Association for Endoscopic Surgery and other Interventional Techniques (EAES), International Society of Digestive Surgery–European Federation (EFISDS) and European Society of Gastrointestinal Endoscopy (ESGE). A targeted literature search was performed to discover recent evidence concerning the management and follow-up of gallbladder polyps. The changes within these updated guidelines were formulated after consideration of the latest evidence by a group of international experts. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence.

Key Point

• These recommendations update the 2017 European guidelines regarding the management and follow-up of gallbladder polyps.

Management and follow-up of gallbladder polyps : Joint guidelines between the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), European Association for Endoscopic Surgery and other Interventional Techniques (EAES), International Society of Digestive Surgery - European Federation (EFISDS) and European Society of Gastrointestinal Endoscopy (ESGE)

Objectives

The management of incidentally detected gallbladder polyps on radiological examinations is contentious. The incidental radiological finding of a gallbladder polyp can therefore be problematic for the radiologist and the clinician who referred the patient for the radiological examination. To address this a joint guideline was created by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR), European Association for Endoscopic Surgery and other Interventional Techniques (EAES), International Society of Digestive Surgery – European Federation (EFISDS) and European Society of Gastrointestinal Endoscopy (ESGE).

Methods

A targeted literature search was performed and consensus guidelines were created using a series of Delphi questionnaires and a seven-point Likert scale.

Results

A total of three Delphi rounds were performed. Consensus regarding which patients should have cholecystectomy, which patients should have ultrasound follow-up and the nature and duration of that follow-up was established. The full recommendations as well as a summary algorithm are provided.

Conclusions

These expert consensus recommendations can be used as guidance when a gallbladder polyp is encountered in clinical practice.

Key Points

• Management of gallbladder polyps is contentious

• Cholecystectomy is recommended for gallbladder polyps >10 mm

• Management of polyps <10 mm depends on patient and polyp characteristics

• Further research is required to determine optimal management of gallbladder polyps

Imaging of Acute Pancreatitis

Acute pancreatitis is an acute inflammation of the pancreas. Several classification systems have been used in the past but were considered unsatisfactory. A revised Atlanta classification of acute pancreatitis was published that assessed the clinical course and severity of disease; divided acute pancreatitis into interstitial edematous pancreatitis and necrotizing pancreatitis; discerned an early phase (first week) from a late phase (after the first week); and focused on systemic inflammatory response syndrome and organ failure. This article focuses on the revised classification of acute pancreatitis, with emphasis on imaging features, particularly on newly-termed fluid collections and implications for the radiologist.

The revised Atlanta classification of acute pancreatitis: its importance for the radiologist and its effect on treatment

An international working group has modified the Atlanta classification for acute pancreatitis to update the terminology and provide simple functional clinical and morphologic classifications. The modifications (a) address the clinical course and severity of disease, (b) divide acute pancreatitis into interstitial edematous pancreatitis and necrotizing pancreatitis, (c) distinguish an early phase (1st week) and a late phase (after the 1st week), and (d) emphasize systemic inflammatory response syndrome and multisystem organ failure. In the 1st week, only clinical parameters are important for treatment planning. After the 1st week, morphologic criteria defined on the basis of computed tomographic findings are combined with clinical parameters to help determine care. This revised classification introduces new terminology for pancreatic fluid collections. Depending on presence or absence of necrosis, acute collections in the first 4 weeks are called acute necrotic collections or acute peripancreatic fluid collections. Once an enhancing capsule develops, persistent acute peripancreatic fluid collections are referred to as pseudocysts; and acute necrotic collections, as walled-off necroses. All can be sterile or infected. Terms such as pancreatic abscess and intrapancreatic pseudocyst have been abandoned. The goal is for radiologists, gastroenterologists, surgeons, and pathologists to use the revised classifications to standardize imaging terminology to facilitate treatment planning and enable precise comparison of results among different departments and institutions.

Neutral vs positive oral contrast in diagnosing acute appendicitis with contrast-enhanced CT: sensitivity, specificity, reader confidence and interpretation time

OBJECTIVE

The study compared the sensitivity, specificity, confidence and interpretation time of readers of differing experience in diagnosing acute appendicitis with contrast-enhanced CT using neutral vs positive oral contrast agents.

METHODS

Contrast-enhanced CT for right lower quadrant or right flank pain was performed in 200 patients with neutral and 200 with positive oral contrast including 199 with proven acute appendicitis and 201 with other diagnoses. Test set disease prevalence was 50%. Two experienced gastrointestinal radiologists, one fellow and two first-year residents blindly assessed all studies for appendicitis (2000 readings) and assigned confidence scores (1=poor to 4=excellent). Receiver operating characteristic (ROC) curves were generated. Total interpretation time was recorded. Each reader's interpretation with the two agents was compared using standard statistical methods.

RESULTS

Average reader sensitivity was found to be 96% (range 91-99%) with positive and 95% (89-98%) with neutral oral contrast; specificity was 96% (92-98%) and 94% (90-97%). For each reader, no statistically significant difference was found between the two agents (sensitivities p-values >0.6; specificities p-values>0.08), in the area under the ROC curve (range 0.95-0.99) or in average interpretation times. In cases without appendicitis, positive oral contrast demonstrated improved appendix identification (average 90% vs 78%) and higher confidence scores for three readers. Average interpretation times showed no statistically significant differences between the agents.

CONCLUSION

Neutral vs positive oral contrast does not affect the accuracy of contrast-enhanced CT for diagnosing acute appendicitis. Although positive oral contrast might help to identify normal appendices, we continue to use neutral oral contrast given its other potential benefits.

Case 117: Actinomycosis of Left Kidney with Sinus Tracts

A 39-year-old Samoan man presented to the emergency department with fever, progressive weakness, and left flank pain of 1-month duration. For several months, he had also experienced progressive weight loss. There was no history of recent trauma, and he was not taking any medication. His medical history was notable for a large left groin abscess and left lower lobe pneumonia of unknown cause 1 year prior to the current admission. Furthermore, he had undergone exploratory laparotomy and gastric surgery for peptic ulcer disease approximately 10 years ago. Physical examination findings were positive for a tender firm mass in the left flank with no associated skin changes. Laboratory findings revealed an elevated white blood cell count of 18 x 10(9)/L. The urine cultures were negative. A computed tomographic (CT) image obtained 1 year prior to the current admission was unremarkable. CT of the abdomen and pelvis (section thickness, 5 mm) was performed after ingestion of 900 mL of 2% diatrizoate meglumine and diatrizoate sodium (Gastrografin; Bracco Diagnostics, Princeton, NJ). A 150-mL dose of iohexol (300 mg of iodine per milliliter) (Omnipaque; Nycomed, New York, NY) was administered intravenously at a rate of 4 mL/sec with a 70-second scan delay. Unenhanced CT images (not shown) did not reveal any areas of high attenuation.

Current Concepts in Imaging of Appendicitis

Appendicitis is the most common cause of acute abdominal pain requiring surgery. Early diagnosis is crucial to the success of therapy. CT and ultrasound are widely recognized as very useful in the timely diagnosis of appendicitis. MR imaging is emerging as an alternative to CT in pregnant patients and in patients who have an allergy to iodinated contrast material. This article reviews the current imaging methods and diagnostic features of appendicitis.

CT imaging of colitis

Computed tomography (CT) is widely used to assess patients with nonspecific abdominal pain or who are suspected of having colitis. The authors recommend multidetector CT with oral, rectal, and intravenous contrast material and thin sections, which can accurately demonstrate inflammatory changes in the colonic wall and help assess the extent of disease. In most cases, the final diagnosis of the type of colitis is based on clinical and laboratory data and colonoscopic and biopsy findings, but specific CT features help narrow the differential diagnosis. Ulcerative colitis is distinguished from granulomatous colitis (Crohn disease) in terms of location of involvement, extent and appearance of colonic wall thickening, and type of complications. Ulcerative colitis and Crohn disease (granulomatous colitis) are rarely associated with ascites, which is often seen in infectious, ischemic, and pseudomembranous colitis. Pseudomembranous colitis also demonstrates marked wall thickening and, occasionally, skip areas but is associated with broad-spectrum antibiotic treatment or chemotherapy. Neutropenic colitis is characterized by right-sided colonic and ileal involvement, whereas ischemic colitis is characterized by vascular distribution pattern and history. Diverticulitis is a focal asymmetric process with fascial thickening and inflamed diverticula. Dilatation of a thick-walled appendix with increased enhancement and adjacent stranding suggests appendicitis, but inflammatory changes may extend to the cecum and terminal ileum. Epiploic appendagitis is a focal rim-enhancing area next to the colon, usually without any substantial colonic wall thickening.

Detection of hepatocellular carcinoma by ferumoxides-enhanced MR imaging in cirrhosis: Incremental value of dynamic gadolinium-enhancement

PURPOSE

To investigate the incremental value of dynamic gadolinium-enhancement performed immediately after ferumoxides-enhanced magnetic resonance (MR) imaging on the detection of hepatocellular carcinoma in patients with cirrhosis.

MATERIALS AND METHODS

We retrospectively reviewed MR scans of 62 cirrhotic patients over a two-year period. Sequences included ferumoxides-enhanced T2-weighted fast spin echo followed by dynamic gadolinium-enhanced T1-weighted spoiled gradient echo. Two readers independently documented the presence of hepatocellular carcinoma on a three-point confidence scale, without and with gadolinium-enhanced images. The presence or absence of hepatocellular carcinoma was established by histopathology (58 patients) or follow-up imaging (four patients) over a mean period of nine months.

RESULTS

A total of 71 hepatocellular carcinomas were found in 42 patients. There was no statistically significant difference in sensitivity for the diagnosis of hepatocellular carcinoma without vs. with gadolinium-enhanced images (68% vs. 74% for reader 1 and 62% vs. 73% for reader 2, respectively, P > 1.3). However, both readers showed a lower mean confidence for tumor detection without vs. with gadolinium-enhanced images (2.3 vs. 2.7 for reader 1, 2.3 vs. 2.9 for reader 2, P < 0.01).

CONCLUSION

In our study, the addition of dynamic gadolinium-enhancement to ferumoxides-enhanced MR imaging did not improve hepatocellular carcinoma detection, but the addition of gadolinium-enhancement is recommended if ferumoxides-enhanced imaging is used because it increased reader confidence.

Early nonenhanced abdominal computed tomography can predict mortality in severe acute pancreatitis

We wondered whether nonenhanced computed tomography (CT) within 48 hours of admission could identify individuals at risk for higher mortality from acute pancreatitis. Data from the international phase III study of the platelet-activating factor-inhibitor Lexipafant was used to analyze noncontrast CT versus acute pancreatitis mortality. Nonenhanced CT examinations of the abdomen from the trial were classified by disease severity (Balthazar grades A-E) and then correlated with patient survival. Among the 477 individuals who underwent CT within 48 hours of admission and 220 individuals who did so over the subsequent 6 days, higher CT grades were associated with increased mortality. Each unit increase in Balthazar grade during the initial 48 hours was associated with an estimated increase in the risk of mortality of 33%, and this trend increased to 50% if pancreatic enlargement and peripancreatic stranding (grades B and C) were combined (P<0.05). CT grade correlated minimally with Ranson, Glasgow, or APACHE II score during the initial 48 hours; however, this correlation improved over 3-8 days. Early nonenhanced abdominal CT in patients with acute pancreatitis is a valuable prognostic indicator of mortality in acute pancreatitis, even among patients without clinical features of severe acute pancreatitis.

Case report. Uterine lipoma: advantage of MRI over ultrasound

Pure fatty tumours of the uterus are exceedingly rare. A case of uterine lipoma demonstrated on ultrasound and MRI with pathological correlation is described. Ultrasound suggested the presence of a uterine lipoma but MRI permitted an unequivocal diagnosis. The usefulness of the various imaging methods is discussed in correctly diagnosing this entity and avoiding unnecessary surgery in the asymptomatic patient.

Necrotizing pancreatitis: a surgical approach independent of documented infection

BACKGROUND

Strategies for the management of patients with necrotizing pancreatitis remain controversial. While consensus opinion supports operative necrosectomy for the treatment of infected pancreatic necrosis, the timing for surgical intervention is not completely resolved. Further, the indication for the surgical management of sterile pancreatic necrosis is also subject to debate.

METHODS

The objective of this study was to evaluate outcome measures for the surgical management of necrotizing pancreatitis, independent of documented infection. A retrospective review was undertaken between 1994 and 2002 at a single county hospital.

RESULTS

Twenty-one patients with CT-documented necrotizing pancreatitis underwent operative pancreatic necrosectomy with laparostomy within 21 days of initial diagnosis and had an average of three reoperations. Average length of stay (LOS) in the ICU was 36 days and in the hospital 67 days. Ten patients had documented infected necrosis based on initial intra-operative cultures, while I I had sterile necrosis. Overall, 95% (20/21) of the patients had a complication, with an average of three complications per patient. Common complications included ARDS (71%), sepsis (33%), renal failure (24%), and pneumonia (24%). The overall mortality rate was 14% (3/21), with a mean follow-up of 469 days.

DISCUSSION

The surgical management of acute necrotizing pancreatitis, independent of documented infection, can be undertaken within 3 weeks of diagnosis with an acceptable morbidity and a low mortality rate. Creation of a laparostomy to enable ready, atraumatic debridement of the retroperitoneum is a safe alternative to standard repeat laparotomies and thus represents a useful adjunct to the surgical management of necrotizing pancreatitis.

Detection of hepatic metastases from cancers of the gastrointestinal tract by using noninvasive imaging methods (US, CT, MR imaging, PET): a meta-analysis

PURPOSE

To perform a meta-analysis to compare current noninvasive imaging methods (ultrasonography [US], computed tomography [CT], magnetic resonance [MR] imaging, and (18)F fluorodeoxyglucose [FDG] positron emission tomography [PET]) in the detection of hepatic metastases from colorectal, gastric, and esophageal cancers.

MATERIALS AND METHODS

A MEDLINE literature search and review of article bibliographies and our institutional charts of patients with colorectal cancer identified data with histopathologic correlation or at least 6 months of patient follow-up. Two authors independently abstracted data sets and excluded data without contingency tables or data published more than once. Summary-weighted estimates of sensitivity were obtained and stratified according to specificity of less than 85% or 85% and higher. A covariate analysis was used to evaluate the influence of patient- or study-related factors on sensitivity.

RESULTS

Among 111 data sets, nine US (509 patients), 25 CT (1,747 patients), 11 MR imaging (401 patients), and nine PET (423 patients) data sets met the inclusion criteria. In studies with a specificity higher than 85%, the mean weighted sensitivity was 55% (95% CI: 41, 68) for US, 72% (95% CI: 63, 80) for CT, 76% (95% CI: 57, 91) for MR imaging, and 90% (95% CI: 80, 97) for FDG PET. Results of pairwise comparison between imaging modalities demonstrated a greater sensitivity of FDG PET than US (P =.001), CT (P =.017), and MR imaging (P =.055).

CONCLUSION

At equivalent specificity, FDG PET is the most sensitive noninvasive imaging modality for the diagnosis of hepatic metastases from colorectal, gastric, and esophageal cancers.

Focal fatty infiltration of the liver: analysis of prevalence and CT findings in children and young adults

OBJECTIVE

Focal fatty infiltration of the liver, a benign entity that can be confused with a malignant lesion, is well characterized in adults but not in children. The goal of this study was to determine by CT the prevalence and characteristics of focal fatty infiltration in children and young adults.

MATERIALS AND METHODS

We retrospectively analyzed 305 consecutive contrast-enhanced abdominal CT examinations of 218 children and young adults with no known liver disease, performed during 2 years at our institution, to identify focal fatty infiltration of the liver. The imaging criterion for focal fatty infiltration of the liver on helical CT was a geometric or ovoid low-attenuation area adjacent to the falciform ligament, gallbladder fossa, or porta hepatis. If a patient's findings met the CT criterion for focal fatty infiltration of the liver, all previous abdominal CT and MR imaging examinations performed for that patient were reviewed to assess the evolution of focal fatty infiltration of the liver.

RESULTS

Of 218 children and young adults, 20 (9.2%) met the CT criterion for focal fatty infiltration of the liver. In our population, focal fatty infiltration of the liver was identified only adjacent to the falciform ligament. The prevalence of focal fatty infiltration of the liver increased significantly with advancing age: 0% for ages 1 month-4 years; 7.3% for 5-9 years; 10.2% for 10-14 years, and 25.6% for 15-19 years (p < 0.0001).

CONCLUSION

Focal fatty infiltration of the liver was identified in 9.2% of patients in our population, and occurrence of this lesion in children increases significantly with advancing age. However, focal fatty infiltration of the liver is uncommon in infants and young children and should be a diagnosis of exclusion.

Detection of small, functional islet cell tumors in the pancreas: selection of MR imaging sequences for optimal sensitivity

PURPOSE

To determine the sensitivity and specificity of magnetic resonance (MR) imaging for depicting pancreatic small, functional islet cell tumors and the minimum number of sequences for expedient diagnosis.

MATERIALS AND METHODS

Twenty-eight patients clinically suspected to have functional islet cell tumors underwent T1- and T2-weighted spin-echo (SE) MR imaging with and without fat suppression, T2-weighted fast SE imaging, and spoiled gradient-echo (GRE) imaging before and after injection of gadopentetate dimeglumine. Sensitivity, specificity, and the best and minimum number of sequences for definitive diagnosis were determined.

RESULTS

MR images depicted proved islet cell tumors in 17 of 20 patients (sensitivity, 85%). Images were true-negative in eight patients with negative follow-up examination results for more than 1 year. Specificity was 100%; positive predictive value, 100%; and negative predictive value, 73%. Among 20 patients with tumor, T1-weighted SE images with fat suppression and nonenhanced spoiled GRE images each showed lesions in 15 (75%); T2-weighted conventional SE with fat suppression, in 13 (65%); gadolinium-enhanced spoiled GRE, in 12 (60%); and T2-weighted fast SE, in seven of 10 patients (70%).

CONCLUSION

MR imaging accurately depicts small islet cell tumors. T2-weighted fast SE and spoiled GRE sequences usually suffice. Gadolinium-enhanced sequences are needed only if MR imaging results are equivocal or negative.

A multisite phase III study of the safety and efficacy of a new manganese chloride-based gastrointestinal contrast agent for MRI of the abdomen and pelvis

The purpose of this study was to evaluate the safety and efficacy of a manganese chloride-based oral magnetic resonance (MR) contrast agent during a Phase III multisite clinical trial. Two hundred seventeen patients were enrolled who were already scheduled for MRI of the abdomen and/or pelvis. In this group of patients, it was postulated that the use of an oral agent would better allow discrimination of pathology from bowel. Patients with known gastrointestinal pathology including peptic ulcer disease, inflammatory bowel disease, obstruction, or perforation were excluded to minimize confounding variables that could affect the safety assessment. Of these 217 patients, 18 received up to 900 mL of placebo, and 199 patients were given up to 900 mL of a manganese chloride-based oral contrast agent, LumenHance (Bracco Diagnostics, Inc.). Safety was determined by comparing pre- and post-dose physical examinations, vital signs, and laboratory examinations and by documenting adverse events. Efficacy was assessed by unblinded site investigators and two blinded reviewers who compared pre- and post-dose T1- and T2-weighted MRI scans of the abdomen and/or pelvis. In 111 (57%) of the 195 cases evaluated for efficacy by site investigators (unblinded readers), MRI after LumenHance provided additional diagnostic information. Increased information was found by two blinded readers in 52% and 51% of patients, respectively. In 44/195 cases (23%) unblinded readers felt the additional information would have changed patient diagnosis and in 50 patients (26%), it would have changed management and/or therapy. Potential changes in patient diagnosis or management/therapy were seen by the two blinded readers in 8-20% of patients. No clinically significant post-dose laboratory changes were seen. Forty-eight patients (24%) receiving LumenHance and four patients (22%) receiving placebo experienced one or more adverse events. Gastrointestinal tract side effects were most common, seen in 29 (15%) of LumenHance patients and in 3 (17%) of the placebo patients. LumenHance is a safe and efficacious oral gastrointestinal contrast agent for MRI of the abdomen and pelvis.

Safe and easy power injection of contrast material through a central line

Power-assisted injection of contrast material into an antecubital vein is commonly used in CT and has been proven superior to manual injection. Power-assisted injection through a central line bares the risk of rupturing the line because manual control over the pressure applied by the power injector is lacking. We present a simple safety device which allows manual control of the pressure by means of an interposed three-way stopcock combined with a small syringe for pressure equalization.

Breath-hold MR cholangiography with snapshot techniques: prospective comparison with endoscopic retrograde cholangiography

PURPOSE

To compare findings with magnetic resonance (MR) cholangiography with rapid acquisition with relaxation enhancement (RARE) and half-Fourier acquisition with single-shot turbo spin-echo (hereafter, half Fourier RARE) snapshot imaging techniques to those with endoscopic retrograde cholangiography (ERC).

MATERIALS AND METHODS

Heavily T2-weighted thick-section (RARE) and thin-section (half-Fourier RARE) MR cholangiography were performed prospectively, on a 1.5-T imager, in the biliary tree of 61 consecutive patients before ERC. Findings at ERC were considered the standard of reference. The radiologist and endoscopist were blinded to each other's report. On- and off-site MR cholangiographic readings were performed to detect stones (n = 24), biliary dilatation (n = 34), or stenosis (n = 36).

RESULTS

The sensitivity and specificity of MR cholangiography, respectively, calculated on a lesion-by-lesion basis, were 92.3% and 95.8% for cholangiolithiasis, 94.1% and 92.6% for duct dilatation, and 88.8% and 84.0% for stenosis. With snapshot MR cholangiography, on a patient-by-patient basis, differentiation between normal (n = 15) and abnormal (n = 46) results yielded a sensitivity of 92.4%, a specificity of 83.4%, and a positive predictive value of 95.6%. Pitfalls were caused by flow artifacts, compression by vessels, and low contrast between calculi and surrounding parenchyma.

CONCLUSION

Snapshot MR cholangiography allowed noninvasive, accurate detection of biliary stones, strictures, and dilatation similar to that with ERC. Discrepancies regarding low-grade dilatation and strictures had no clinical relevance at retrospective review.

Colorectal cancer. Radiologic staging

The role of conventional CT scan and conventional MR imaging in assessing patients with colorectal tumors is now well established. Because both techniques have an unacceptably low accuracy for identifying the early stages of primary colorectal cancers (T1, T2N0 or N1 and early T3N0 or N1, or Dukes stage A, B1 and 2, and C1), their routine use for preoperative staging is not recommended. This low staging accuracy is related to the fact that neither method can assess the depth of tumor infiltration within the bowel wall and both have difficulty in diagnosing malignant adenopathy. These distinctions are necessary in order to determine correctly patient prognosis and tumor resectability. If the various publications on CT scan and MR imaging staging of primary colon tumors are summarized, a mean overall accuracy of approximately 70% can be established. The sensitivity for lymph node detection of malignant lymphadenopathy is only about 45%. The sensitivity for detection of positive lymph nodes is better for rectal tumors because any adenopathy in the perirectal area can be considered malignant because benign adenopathy is not seen in this area. For the early stages of colon cancer or recurrent tumor at the anastomotic site, endoscopic ultrasound or TRUS is the method of choice. Both TRUS and MR imaging with endorectal coils can demonstrate the various layers of the rectal wall, but the ultrasonographic examination can be performed at lower cost and is less time-consuming. Despite these limitations CT scan and MR imaging are useful for assessing patients suspected of having extensive disease, including invasion of fat or neighboring organs or metastatic spread to distant sites including, liver, adrenals, lung, and so forth. CT scan and MR imaging are also helpful in the following ways: in determining whether a patient will benefit from preoperative radiation or whether a patient with rectal cancer can undergo a sphincter-saving procedure; for designing radiation ports; and for detecting complications related to the neoplasm, such as perforation with abscess formation or preobstructive ischemia in patients with complete obstruction by tumor. In these cases, management often is based on CT scan and MR imaging findings and cross-sectional follow-up studies can establish the success of treatment. CT scan and MR imaging have a premier role in the detection of recurrent colorectal cancer. CT scan and MR imaging are superior to colonoscopy for diagnosing extrinsic mass-like tumor recurrences and they are the only methods by which patients with total AP resection can be fully evaluated. The overall accuracy of CT scan and MR imaging for detecting recurrent colorectal tumors ranges from 90% to 95%. Following AP resection, CT scan cannot reliably determine whether a soft tissue density in the surgical bed represents recurrent tumor, and it is important to obtain CT scan baseline studies 4 months after surgery and to repeat this examination at 6-month intervals. Scar tissue, even if initially masslike, shrinks over time and after 1 year should be smaller and its margins more sharply defined. Any apparent increase in size of a mass or any demonstration of adenopathy must be considered an indication for biopsy. Recurrent tumors that do not extend to the pelvis or abdominal sidewalls or invade bone or nerves can be resected. Subtle tumor recurrence or tumor foci in small nodes can be detected by PET scan and immunoscintigraphy, but their future role in the diagnostic imaging of colorectal cancer patients depends on the results of ongoing studies. Helical CT scan has the advantages of fast volume scanning associated with optimal bolus delivery, absence of artifacts related to motion, absence of missed slices, and availability of reformations in multiple planes and three-dimensional reconstruction (virtual reality). The role of this technique in patients with colorectal neoplasms has not been defined. (ABSTRACT TRUNCATED)

Diagnosis of duodenal leaks from kidney-pancreas transplants in patients with duodenovesical anastomoses: value of CT cystography

OBJECTIVE

This study was undertaken to assess the value of CT cystography, using scans made with full bladder distention by a combination of iodinated contrast material and air and scans made after active voiding, for detecting duodenal segment leaks in patients with kidney transplants and pancreas transplants associated with small duodenal segments and duodenovesical anastomoses.

SUBJECTS AND METHODS

18 patients with such kidney-pancreas transplants underwent CT cystography for clinically suspected leaks from the duodenal segment. Six patients had two examinations, resulting in 24 CT cystograms. The CT protocol consisted of an initial series of pelvic scans (plain CT) without oral, IV, or bladder contrast material; CT cystogram with the bladder fully distended by iodinated contrast material and air; and, if the findings were negative, CT after voiding. If no leak was demonstrated, the remainder of the abdomen to the liver dome was examined. Diagnoses were proved by surgery or cystoscopy (n = 11) and clinical follow-up examinations (n = 13).

RESULTS

Overall, bladder-duodenal segment leaks were demonstrated in 11 of 12 studies: one by plain CT, seven by full CT cystography, and four by CT after voiding following negative findings on full CT cystography. One surgically proved leak was missed by CT cystography owing to a large amount of pelvic fluid. In 12 studies without a leak, CT cystography results correlated well with clinical follow-up studies. There were no false-positive results. Sensitivity was 92%, specificity was 100%, and accuracy was 96%.

CONCLUSION

CT cystography with a dedicated protocol is an accurate way to diagnose leaks of the duodenal segment in patients with bladder-drained kidney-pancreas transplants if administration of air combined with contrast material into the bladder and CT after voiding are used.

The role of imaging in patients with ascites

Imaging plays a significant role in patients with ascites for assessing the size and the causes of ascitic fluid, for assisting sampling or draining of ascitic fluid, for selecting candidates for TIPS placement, and for surveilling and detecting complications after TIPS placement. Sonography and CT are primary imaging tools, and MR imaging is used in selected cases such as demonstration of peritoneal or ascitic fluid enhancement, particularly in patients with compromised renal function. Interventional procedures combined with CT and sonography play a major role in the assessment of patients considered for TIPS placement because of refractory esophageal bleeding or ascites. Before the TIPS procedure, these procedures are used to exclude contraindications such as polycystic liver disease, hypervascular hepatic tumors, and portal vein thrombosis. After the TIPS procedure, sonography combined with interventional procedures is used to detect immediate complications such as hemorrhage or intractable shunt-induced encephalopathy due to excessive portosystemic diversion and to detect and treat mid- to long-term complications such as shunt stenosis and occlusion through a routine surveillance program.

CT for the evaluation of carcinomas in the colon and rectum

The role of conventional CT in assessing patients with colorectal tumors is well established. The low accuracy of CT for identifying early stages of primary colorectal cancers prevents the routine use of CT for preoperative staging. Nevertheless, CT is useful in examining patients suspected of having extensive disease, in deciding whether a patient will benefit from preoperative radiation, in designing radiation ports, and in detecting complications related to the neoplasm. For recurrent colorectal neoplasm, CT has the premier role. CT surpasses colonoscopy in detecting early masslike tumor recurrence at the anastomotic site because of its extrinsic component, and CT and MRI are the only methods that can fully evaluate cases of total abdominoperineal resection. After total abdominoperineal resection, however, CT cannot determine with certainty that a soft tissue density in the surgical bed represents recurrent tumor. In patients with colorectal neoplasms, preliminary results with multiplanar and three-dimensional reconstructions of helical CT images are promising, but their role needs further investigation.

Current CT/MRI examination of the lower intestinal tract

For evaluating primary colonic and rectal malignancies, CT and MRI are often complementary imaging methods which are useful in assessing patients suspected of having extensive disease and in deciding whether a patient will benefit from preoperative radiation. CT is also helpful in designing radiation ports and in detecting complications related to the neoplasm such as perforation with abscess formation. MRI offers excellent tissue resolution which aids in distinguishing between localized colorectal disease and disease which invades muscle. Also, MRI can add information with coronal views for determining whether a sphincter-saving procedure can be performed, and may be of benefit for assessing the subtle extent of tumour into muscle and bone. However, CT and MRI lack the ability to assess depth of neoplastic involvement within bowel wall. This limitation is the major factor which, combined with the inability to diagnose metastatic tumour foci in normal-sized nodes and microinvasion of perirectal fat, prevents optimal tumour staging. Because of the low accuracy for assessing early cancer stages, neither CT nor MRI are recommended for routine use in preoperative staging. CT and MRI have a premier role in the assessment of recurrent colorectal neoplasm, with CT providing a slightly better overall evaluation due to volume imaging, easy image reconstructions in different planes, and availability of excellent oral and intravenous contrast agents. Cross-sectional imaging is the only method to evaluate fully patients with total AP resection, particularly male patients. Neither CT nor MRI can determine with certainty that a soft tissue density in the surgical bed following total AP resection represents recurrent tumour unless a clear mass is present which has increased in size over time. However, both methods surpass colonoscopy for detecting early mass-like tumour recurrence at the anastomotic site due to its extrinsic component. Cross-sectional imaging plays a prominent role in assessing inflammatory disease of the colon. Clinical history, laboratory data and extent of involvement are used together with results from radiographic examinations to reach a specific diagnosis. CT is preferred over MRI in the assessment of extent of inflammatory disease in and beyond the bowel wall. An additional benefit of CT over MRI is the fact that patients with abscesses or large fluid collection can undergo drainage while still in the CT scanner. CT and MRI can aid in the distinction between ulcerative colitis with minimal wall-thickening and Crohn's disease with marked wall-thickening combined with skip lesions and fistula and/or abscess formation.(ABSTRACT TRUNCATED AT 400 WORDS)

Focal liver lesions: characterization with nonenhanced and dynamic contrast material-enhanced MR imaging

PURPOSE

To evaluate prospectively the diagnostic accuracy of non-enhanced and gadolinium-enhanced magnetic resonance (MR) imaging in characterization of hepatic lesions.

MATERIALS AND METHODS

Fifty-five patients with benign and 52 patients with malignant focal liver lesions underwent examination at 1.5 T that comprised nonenhanced and dynamic contrast material-enhanced images. Four experienced radiologists independently read the different sets of images without and with knowledge of clinical history.

RESULTS

Receiver operating characteristic analysis showed that dynamic contrast-enhanced MR imaging added information to nonenhanced MR studies and thereby improved distinction between benign and malignant lesions (P < .05). Knowledge of clinical data further improved lesion characterization with nonenhanced and combined nonenhanced and contrast-enhanced MR imaging (P < .05).

CONCLUSION

Dynamic contrast-enhanced MR imaging is a useful adjunct for characterization of hepatic lesions. Knowledge of clinical history still has a decisive effect on interpretation of MR images of the liver.

Pancreatic imaging. Computed tomography and magnetic resonance imaging

In the assessment of patients with acute pancreatitis, CT is the modality of choice and should be used in any patient in whom the diagnosis is in doubt, treatment has not been successful, or complications are suspected. Early diagnosis of patients at risk is facilitated by CT, and newly introduced staging criteria have proved to be accurate and helpful in managing these patients. For chronic pancreatitis, CT, ultrasound, and ERCP can be used. ERCP, however, remains the gold standard, owing to its ability to depict the pancreatic duct accurately. Often the morphologic data need to be correlated with exocrine or endocrine dysfunction of the pancreas to obtain an accurate means of staging the severity of chronic pancreatitis. Great advances in imaging of pancreatic neoplasms have been made, and differentiation between various types of tumors involving this gland often can be ascertained. Nevertheless, at this time, the early diagnosis of small, malignant lesions of the pancreas is impossible in many cases. CT and to a lesser degree ultrasound are currently the methods of choice for detecting and staging the pancreatic neoplasms pictorially, whereas ERCP has established itself as the best method for visualizing the pancreatic duct and its changes related to pancreatic neoplasia. MR imaging of the pancreas has come a long way, and further improvements are expected with the use of oral and intravenous contrast agents. At present, MR imaging appears to be mainly a problem-solving modality, but it can show improved results for small lesions (particularly islet cell tumors), which do not alter the contour of the pancreas. MR imaging appears to be capable of discerning between the serous and mucinous components of cystic neoplasms and may have a role in the assessment of patients suspected of pancreas transplant rejection.

Imaging of the liver

The liver continues to be a focus for various imaging methods, but MR imaging received most of the attention with new sequences or modifications of older techniques. Primary and secondary focal liver lesions were studied using various techniques, and most researchers agreed that characterization of lesions is the domain of MR imaging. For actual detection of lesions, particularly for number and size of lesions, CT, especially CT during arterial portography, was still considered the methods of choice. Innovative approaches included three-dimensional image analysis of metastases for segmental localization and fusion of images from several cross-sectional studies for improved characterization of lesions. Assessment of fatty infiltration in the liver was investigated using both CT and MR imaging, but the definitive role of cross-sectional imaging for this purpose is not yet established. Evaluation of venous vascular systems was also investigated using both color Doppler ultrasound and MR imaging, but the role of these techniques vis-á-vis each other needs further definition. Spectroscopy continued to advance but current limitations in localization and processing techniques prevented an enthusiastic endorsement by clinicians. Its potential for assessment of tumor response to chemotherapy is substantial.

Imaging of the liver

New developments in imaging of the liver have continued during the past year. Ultrasonography, particularly color Doppler applications, and invasive CT techniques are used with increasing frequency. New contrast agents are being tested for improved ultrasonographic detection of liver lesions, and faster imaging sequences and variations on older techniques are innovations in the field of MR imaging. Correlation studies addressed the issue of which are the best-suited imaging methods for the various pathologic changes in the liver.

Colorectal cancer: cross-sectional imaging for staging of primary tumor and detection of local recurrence

This review describes the use of cross-sectional imaging in the staging of colorectal carcinoma and detection of local recurrence. The contributions of CT, MR imaging, and sonography are discussed and illustrated. Colorectal carcinoma is the second most common tumor in the United States and the most common cancer in the gastrointestinal tract. The prognosis for patients with this neoplasm is closely related to the extent of tumor at the time of diagnosis. Accurate noninvasive preoperative assessment of tumor stage by one or a combination of radiologic techniques would enable appropriate treatment to be planned in each case. Also, determination of possible tumor recurrence would permit effective monitoring of success of therapy and surgical intervention for recurrent disease before widespread metastasis occurs.

Enteroclysis and small bowel series: comparison of radiation dose and examination time

Respective radiation doses and total examination and fluoroscopy times were compared for 50 patients; 25 underwent enteroclysis and 25 underwent small bowel series with (n = 17) and without (n = 8) an examination of the upper gastrointestinal (GI) tract. For enteroclysis, the mean skin entry radiation dose (12.3 rad [123 mGy]) and mean fluoroscopy time (18.4 minutes) were almost 1 1/2 times greater than those for the small bowel series with examination of the upper GI tract (8.4 rad [84 mGy]; 11.4 minutes) and almost three times greater than those for the small bowel series without upper GI examination (4.6 rad [46 mGy]; 6.3 minutes). However, the mean total examination completion time for enteroclysis (31.2 minutes) was almost half that of the small bowel series without upper GI examination (57.5 minutes) and almost four times shorter than that of the small bowel series with upper GI examination (114 minutes). The higher radiation dose of enteroclysis should be considered along with the short examination time, the age and clinical condition of the patient, and the reported higher accuracy when deciding on the appropriate radiographic examination of the small bowel.

CT detection of asymptomatic pancreatitis following ERCP

Presence or absence of pancreatitis without symptoms attributable to pancreatitis was assessed by computed tomography (CT) in 31 patients who underwent CT following endoscopic retrograde cholangiopancreatography (ERCP) within a time interval of 0-9 days. Presence or absence of pancreatitis was proven by elevated or normal amylase, and/or surgery, and by symptoms related to pancreatitis. Twenty-five of the patients underwent ERCP without and six with sphincterotomies. Among the six patients, additional procedures included two stent placements, two balloon dilatations, and one basket retrieval. Eleven of 31 patients developed pancreatitis following ERCP. The incidence of pancreatitis was higher in the group with maneuvers (four of six patients or 66.7%) than that without maneuvers (seven of 25 or 28%). Asymptomatic pancreatitis was present in five of 31 patients or 16.1%, and three of these had CT evidence of severe pancreatitis. CT demonstration of pancreatitis following ERCP with or without maneuvers may not always indicate clinically relevant disease.

Ileoanal pouches: comparison of CT, scintigraphy, and contrast enemas for diagnosing postsurgical complications

The value of CT of the pelvis, 111In-labeled leukocyte scintigraphy, and contrast enema (pouchography) for detecting postsurgical complications was assessed in 44 patients with total colectomy, rectal mucosectomy, and ileoanal pouches. Ileoanal pouches were created as reservoirs from an ileal loop that was anastomosed to the dentate line of the anus and stayed connected to the remainder of the ileum. This pouch preserves the normal defecatory pathway and eliminates disease-producing mucosa. A total of 57 sets of examinations revealed 22 cases of normal postoperative findings, 22 of pouchitis, 13 of abscess, and three of fistula. Overall sensitivity for detecting complications with pouchography was 60% (18 of 30 findings); with CT, 78% (28 of 36 findings); and with scintigraphy, 79% (23 of 29 findings). Pouchitis was best diagnosed by scintigraphy (sensitivity, 80%), followed by CT (sensitivity, 71%) and pouchography (sensitivity, 53%). Only CT correctly diagnosed all cases of abscess. Fistulas were frequently missed by all three methods. If tests were combined, the overall sensitivity rose to 93% for the combination CT/scintigraphy and to 86% for CT/pouchography, but did not improve for pouchography/scintigraphy (78%). For evaluation of complications in patients with ileoanal pouches, CT should be the initial test. If an abscess is found, no further tests are needed. If CT findings are negative, a scintigram should be obtained. Our data did not establish a clear role for pouchography.

CT evaluation of carcinomas of the colon and rectum

Computed tomography (CT) has proved to be a powerful tool in the detection and staging of carcinomas of the colon and rectum. It is unsurpassed in the detection of recurrent colon cancer and is particularly useful in patients who have undergone abdominal-perineal resections for rectal neoplasms. The current applications of CT in colon cancer are contrasted with barium studies, endoscopy, and magnetic resonance imaging.

MR appearance of the liver after partial hepatectomy

To define the MR appearance of the liver after partial hepatectomy, we reviewed retrospectively 61 MR examinations performed on 25 patients 10 days to 48 months after surgery. Twenty-seven partial hepatectomies performed in the 25 patients included right lobectomy in 11, trisegmentectomy in two, left lobectomy in five, and wedge resection in nine. By using vascular landmarks, demonstration of the falciform ligament, and the presence of surgical clips, we correctly identified the type of partial hepatectomy in 21 of the 25 patients. The signal intensity of the resection margin was similar to that of the remaining parenchyma in 16 of 18 patients and was poorly defined and had a higher signal intensity (T2-weighted image) in the remaining two. Liver regeneration was observed on serial MR scans 2-16 months after surgery. Findings related to chemotherapy, including periportal changes and inhomogeneous appearance of the liver, were shown in six of eight patients. Tumor recurrence was present in nine patients, either intrahepatic (seven patients) or at the resection margin (two patients), and was consistently identified with MR imaging. The ability of MR imaging to produce images without artifacts from surgical clips is helpful in displaying the MR appearance of the liver after partial hepatectomy. Anatomic landmarks, findings related to chemotherapy, and tumor recurrence were shown well.

Hepatic neoplasia: breath-hold MR imaging

Twenty-seven patients with hepatic neoplasms were prospectively examined at 0.35 T with multisection magnetic resonance (MR) imaging during a single breath hold. The procedures included a spin-echo (SE) sequence with a repetition time (TR) of 250 or 125 msec and an echo time (TE) of 15 msec (TR/TE = 250 or 125/15) and gradient-echo (GRE) partial-flip sequences at 250 or 125/20 in phase and 250 or 125/12 out of phase (flip angle of 70 degrees). These procedures were compared with conventional multiacquisition sequences at SE 250/15 (n = 8) in the same patients. GRE partial-flip sequences with a large flip angle provided the optimum combination of contrast and signal-to-noise ratio for imaging hepatic neoplasms, with a signal-difference-to-noise ratio that for in-phase images was 93% greater and for out-of-phase images was 53% greater than that of the SE images. The use of in-phase TEs was preferable to maintain tissue contrast, and presaturation pulses were employed to eliminate vascular pulsation artifacts. All breath-hold procedures provided suppression of motion artifacts superior to that of the short TR, short TE multiacquisition SE imaging. Such sequences should become indispensable for MR imaging of the upper abdomen.

Abdominal and pelvic CT: use of oral metoclopramide to enhance bowel opacification

The value of orally administered metoclopramide hydrochloride to enhance bowel opacification during abdominal and pelvic computed tomography (CT) was analyzed prospectively in 202 patients in a control group and 334 patients in an experimental group who received 10 mg of metoclopramide with the first dose of oral contrast material. Five hundred milliliters of 2% sodium diatrizoate was given orally 45-60 minutes and 30 minutes before the study, and 250 mL was given 5-10 minutes before the study. Opacification of stomach, duodenum, and small and large bowels was graded from 0 to 3+, and the presence of pseudotumors or side effects from metoclopramide were noted. No significant difference was found in the opacification of stomach, duodenum, and jejunum between control and experimental studies. Opacification was significantly better in metoclopramide studies than control studies in the proximal ileum (P less than .05), distal ileum (P less than .05), right colon (P less than .05), and transverse colon (P less than .05). Pseudotumors were seen in 7% of control and 3% of experimental subjects. No side effects were encountered. Routine oral administration of metoclopramide before abdominal and pelvic CT examinations is recommended for rapid opacification of the ileum and proximal colon for all outpatients and for inpatients who must undergo CT on an emergency basis.

The state of radiographic technique in the examination of the colon: a survey in 1987

Results of an extensive multiple-choice questionnaire sent to 175 leading medical centers in the world were analyzed and compared with those of a similar survey from 1976. One hundred sixty-two (93%) responses were received. Both single- and double-contrast enema procedures are still employed, but the use of the double-contrast technique has markedly increased. Preparation of the colon is even more meticulous than in 1976 and is equal for both techniques. Pharmacologic aids are used more often but preparatory enemas less frequently than in 1976. The use of fluoroscopic equipment has not significantly changed. The decision on the appropriate sequence for the barium enema examination and colonoscopy is based on the individual clinical problem in the majority of cases, and the time interval between the barium enema examination and lower endoscopy with or without biopsy is significantly shorter than in 1976. The use of computed tomography and magnetic resonance imaging has increased since 1976, but angiography is used less often and mostly for unknown causes of bleeding and to stop bleeding.

Detection and staging of renal neoplasms: a reassessment of MR imaging

The use of magnetic resonance (MR) imaging in the detection and staging of renal neoplasms was investigated in 104 patients with 106 renal cell carcinomas confirmed at surgery or autopsy. Overall, MR imaging demonstrated 101 of 106 lesions (95%), including all 93 tumors that were larger than 3 cm in diameter but only eight of the 13 smaller tumors (62%). MR imaging enabled accurate staging of 82% of all detected lesions but led to the understaging of nine lesions and the overstaging of nine. At present, MR imaging cannot be used as a screening modality for renal tumors. However, its negative predictive values of 98% and 99%, respectively, for the evaluation of tumor vascular extension and tumor spread to adjacent structures makes it an excellent staging modality that should be used when the CT findings are equivocal. MR imaging is not accurate in indicating bowel and mesentery involvement, but rapid technical advances and the introduction of bowel contrast medium may improve this present limitation.