Tc-99m sulfur colloid and Tc-99m tagged red blood cell methods are comparable for detecting lower gastrointestinal bleeding in clinical practice

Menstruation Confounding the Correct Interpretation of 99m Tc-RBC Bleeding Scan

ABSTRACT

99m Tc-RBC bleeding scan in a 17-year-old adolescent girl showed an increased focal activity in the pelvis. However, SPECT/CT showed that this activity was located in the uterus, which was considered a normal variant considering that the patient was in her fourth day of the menstrual period. Subsequent 99m TcO 4- Meckel scan showed the typical characteristic of ectopic gastric mucosa in the small bowel. Postsurgical pathology confirmed the diagnosis of ectopic gastric mucosa. This case suggested the menstrual period uterus should be included as differential diagnosis of 99m Tc-RBC scan.

Imaging of Gastrointestinal Bleeding: An Update

Imaging of gastrointestinal bleeding crucial in the diagnosis of occult gastrointestinal bleeding. Gastrointestinal bleeding scintigraphy is a well-established study to aid localisation of gastrointestinal bleeding site. This article discusses about the use of gastrointestinal bleeding scintigraphy in its current practice with emphasis on radiopharmaceutical, imaging techniques, interpretation and pitfalls. There is also discussion on the use of Single Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) within this method of scintigraphy. Meckel's diverticulum is known to be a frequent source of bleeding, mainly in children. It is also know that nuclear medicine imaging can help with Meckel's diverticulum identification. This article also discusses about the technique, imaging, interpretation and SPECT-CT usage for Meckel's diverticulum imaging.

Incidental Detection of Ectopic Ovary Varices by 99mTc-Red Blood Cell Bleeding Scintigraphy in a Patient With Cirrhosis

ABSTRACT

A 72-year-old woman with cirrhosis underwent a 99mTc-labeled red blood cell (RBC) bleeding scan because of recurrent gastrointestinal bleeding. The images showed abnormal 99mTc-RBC accumulation in a mass in the region of the left ovary. Contrast-enhanced CT showed expansion of left ovary vein from the left renal vein, which twisted into an enhanced round mass in the left ovary area. Finally, a diagnosis of ectopic ovary varices was made, which is secondary to cirrhosis with portal hypertension. Ovary varices should be included as differential diagnoses of 99mTc-RBC bleeding scintigraphy.

Incidental Detection of Pancreatic Arteriovenous Malformation by 99mTc-RBC SPECT/CT

A patient with multiple episodes of gastrointestinal bleeding underwent Tc-labeled red blood cell scintigraphy to detect the source of bleeding, which showed a focally increased activity in the upper midabdomen. SPECT/CT demonstrated that the activity was located in the pancreatic head. Angiography confirmed the diagnosis of pancreatic arteriovenous malformation. After transarterial embolization therapy, the patient no longer had bleeding episode. Based on the present case, pancreatic arteriovenous malformation should be included as differential diagnosis during Tc-red blood cell scintigraphy.

The role of imaging in gastrointestinal bleed

Gastrointestinal (GI) bleed accounts for approximately 20% of emergency visits; 2% of hospital admissions and its incidence has been increasing. In patients where the GI bleed does not stop spontaneously, intervention is required to identify the source of bleeding and stop the hemorrhage. Although identifying the source of bleeding can be challenging due to the vast number of underlying etiologies, radiology plays a vital role in patients where endoscopy and/or medical management fail. Radiology offers both non-invasive and invasive options for the diagnosis as well as management of GI bleeds. Scintigraphy and computed tomography angiography (CTA) are the most important non-invasive imaging tests that can identify presence of and help locate the site of bleeding and are used when the patient is hemodynamically stable. If the patient is hemodynamically unstable, conventional angiography (CA) allows diagnosis of the presence, site of bleeding as well as the means of treating the bleed by embolization. Our review article focuses on the various etiologies of GI bleed, the role of imaging in diagnosis as well as treatment of these patients based on the underlying etiologies, the merits and disadvantages of each of these modalities with emphasis on triaging patients for the most appropriate imaging test to guide the most suitable management.

Gastrointestinal hemorrhage: evaluation with MDCT

Gastrointestinal (GI) bleeding is a common medical problem, with high associated morbidity and mortality. The clinical presentation of gastrointestinal hemorrhage varies with the location of the bleeding source, the intensity of the bleed, and the presence of comorbidities that affect the ability to tolerate blood loss. Conventional endoscopic examinations are usually the initial diagnostic tests in patients presenting with overt gastrointestinal hemorrhage. However, implementation of upper tract endoscopy and colonoscopy in the emergency setting can be challenging due to inconsistent availability of the service and difficulties in achieving adequate colonic cleansing in emergent situations. Thus, imaging tests are often relied upon to establish the location and the cause of bleeding, either for initial diagnosis or after non-revealing upper and lower tract endoscopies ("obscure" bleeding). This article discusses the imaging evaluation of patients with gastrointestinal bleeding and reviews the imaging appearance of the most common causes, taking into account the two most relevant clinical presentations: overt bleeding and obscure bleeding.

Nuclear medicine tests for acute gastrointestinal conditions

Acute cholecystitis (AC) and lower-gastrointestinal (GI) bleeding are 2 emergencies commonly encountered in nuclear medicine. Evidence of AC on hepatobiliary scintigraphy (HBS) allows for confident diagnosis and provides support for definitive surgical treatment. Proper patient preparation is essential for HBS including fasting and the use of pharmacologic adjuncts is sometimes required. Pharmacologic adjuncts may also be administered during HBS to shorten the length of the examination and increase its specificity. In the interpretation of HBS, there are several sources of false-positive results to be aware of, most commonly chronic cholecystitis. False-negative results on HBS are usually the result of mistaking another structure, such as a dilated cystic duct, for the gallbladder. Abdominal ultrasound is the appropriate initial test in patients with suspected AC, but HBS is an excellent second tier test for the diagnosis of AC in the work-up of indeterminate cases by sonography. GI bleeding scintigraphy plays an important role in the evaluation and management of patients with acute lower-GI bleeding. Scintigraphy serves to localize sites of active GI bleeding and stratify those patients who would benefit from aggressive treatment (surgery or arteriography) vs those who can be managed medically. Pretest involvement of respective services is critical for successful bleeding site confirmation and therapy by interventional radiology or surgery or both. Single photon emission computed tomography/computed tomography erythrocyte scintigraphy has demonstrated superior accuracy and precision over planar scintigraphy in the diagnosis of acute GI bleeding. Additionally, single photon emission computed tomography/computed tomography scintigraphy of GI bleeding provides useful supplemental anatomical information that benefits patient management.

Imaging of gastrointestinal bleeding

Radiological techniques are important in evaluating patients with gastrointestinal bleeding. Scintigraphic, computed tomographic angiographic, and enterographic techniques are sensitive tools in identifying the source of bleeding and may be useful in identifying patients likely to have a benign course and in selecting patients for therapeutic intervention. Angiography plays a key role in bleeding localization, and modern embolization techniques make this a viable therapeutic option. With the refining developments in body imaging and related reconstructive techniques, it is likely that radiological interventions will play an expanding and critical role in evaluating patients with gastrointestinal hemorrhage in the future.

Consensus and controversies in platelet transfusion

Platelet transfusion therapy is the standard of care for thrombocytopenic patients with hemato-oncological disorders and bone marrow failure states due to intensive chemoradiotherapy. Guidelines to lower triggers for prophylactic and therapeutic transfusions are being developed based on better levels of evidence. The optimum transfusion dose, the choice of platelet concentrate and transfusion interval pose a challenge to balance scientific advances with cost-effective strategies. Platelet refractoriness requires "matched" platelets and is a difficult to treat phenomenon. Pathogen inactivation is a crucial issue in view of susceptibility of platelet concentrates to bacterial contamination. This article reviews the current developments and challenges in optimizing platelet transfusion therapy.

Surgical treatment concepts for acute lower gastrointestinal bleeding

BACKGROUND AND PURPOSE

To this day, the diagnostic and therapeutic strategy for acute lower gastrointestinal hemorrhage requiring transfusion varies among different hospitals. The purpose of this paper was to evaluate our own data on the group of patients presented and to outline our diagnostic and therapeutic regime taking into account the literature of the past 30 years.

METHODS

Following prospective data collection on 63 patients of a university hospital (40 male, 23 female patients) who received surgical intervention for acute lower intestinal hemorrhage requiring transfusion, we retrospectively analyzed the data. After a medical history had been taken, all patients underwent clinical examination, including digital palpation; 62 patients underwent procto-rectoscopy, 38 gastroscopy and colonoscopy, 52 patients colonoscopy only, and 45 patients gastroscopy only. Angiography was applied in 14 cases and scintigraphy in 20 cases.

RESULTS

Diagnostic procedures to localize hemorrhage were successful in 61 cases, 41 of which through endoscopy, 12 through angiography, and eight through scintigraphy. Of our group of patients, 32 suffered from a bleeding colonic diverticulum, eight from angiodysplasia, and five from bleeding small bowel diverticula. Five patients had inflammatory bowel disease and three neoplasia. Among the surgical interventions, segmental resections were performed most frequently (15 sigmoidectomies, 11 small bowel segmental resections, 11 left hemicolectomies, seven right hemicolectomies, one proctectomy). Subtotal colectomies were carried out in ten cases. The complication rate for this group of critically ill, negatively selected patients was 60.3% and the mortality rate was 15.9%.

CONCLUSIONS

Examination and stabilization of the patient is directly followed by diagnostic localization. Today, we primarily rely on nonsurgical control of hemorrhage by endoscopy or angiography; the indication for surgery is mainly limited to peracute, uncontrollable, and recurrent forms. In the case of surgery, intestinal segmental resection is recommended after identification of the lesion; if the localization of colonic hemorrhage is uncertain, subtotal resection is the method of choice. For stable patients with unverifiable small-bowel hemorrhage we recommend regular re-evaluation.

Significance of scintigraphy for the localization of obscure gastrointestinal bleedings

AIM: To determine the role of scintigraphy in patients with gastrointestinal (GI) bleeding of unknown localization.

METHODS: We performed retrospective analyses on 92 patients receiving scintigraphies from 1993 to 2000 in the University of Regensburg hospital, which were done for localization of GI bleeding as a diagnostic step after an unsuccessful endoscopy. In addition to the scintigraphies, further diagnostic steps such as endoscopy, angiography or operations were performed. In some of the scintigraphies with negative results, a provocation test for bleeding with heparinisation was carried out.

RESULTS: 73% of all scintigraphies showed a positive result. In 4.5% of the positive results, the source was located in the stomach, in 37% the source was the small bowel, in 25% the source was the right colon, in 4.5% the source was the left colon, and in 20% no clear localization was possible. Only 4% of all scintigraphies were false positive. A reliable positive scintigraphy was independent of the age of the examined patient. A provocation test for bleeding with heparin resulted in an additional 46% of positive scintigraphies with a reliable localization in primary negative scintigraphies.

CONCLUSION: Our results show that scintigraphy and scintigraphy with heparin provocation tests are reliable procedures. They enable a reliable localization in about half of the obscure GI-bleeding cases. Scintigraphy is superior to angiography in locating a bleeding. It is shown that even in the age of video capsule endoscopy and double-balloon enteroscopy, scintigraphy provides a reliable and directed localization of GI bleeding and offers carefully targeted guidance for other procedures.

Lower gastrointestinal bleeding: a review

Lower gastrointestinal bleeding (LGIB) continues to be a problem for physicians. Acute LGIB is defined as bleeding that emanates from a source distal to the ligament of Treitz. Although 80% of all LGIB will stop spontaneously, the identification of the bleeding source remains challenging and rebleeding can occur in 25% of cases. Some patients with severe hematochezia require urgent attention to minimize further bleeding and complications. This article reviews the causes, diagnostic methods, and endoscopic treatment of LGIB.

Clinical variables associated with positive angiographic localization of lower gastrointestinal bleeding

BACKGROUND

Localizing the source of severe lower gastrointestinal (GI) bleeding is often difficult but is important to plan the extent of colonic resection. The purpose of the present paper was to audit the Auckland Hospital experience of selective angiography, in localizing lower GI bleeding.

METHODS

Patients admitted to Auckland Hospital with rectal bleeding and who subsequently had angiography were evaluated by reviewing their clinical notes and radiological results during a 7-year period (1997-2003). Data collected included demographic details, haemodynamic parameters, change in haemoglobin level, requirement of blood transfusion within 24 h before the procedure, site of the bleeding and pathology.

RESULTS

The notes of 88 patients (male, n = 51; median age 69 years, range 8-99 years) were available for review and analysis. The site of bleeding was localized in 38 (51%); 30 of them had bleeding in the right colon or small bowel and eight in the left colon. Positive localization correlated with: haemodynamic instability P < 0.0001; drop in haemoglobin level of > or =50 from previous admission (P = 0.02); transfusion requirement of > or =5 units of blood within 24 h (P < 0.0001). Logistic regression analysis showed transfusion requirement of > or =5 units to achieve haemodynamic stability to be the most powerful predictor of accurate localization (odds ratio, 40).

CONCLUSION

Catheter angiography for acute lower GI bleeding will successfully localize a point of bleeding in approximately 50% of patients. The most useful clinical indicator for positive angiography was haemodynamic instability particularly in those who require transfusion of > or =5 units of blood to achieve haemodynamic stability.

Lower GI bleeding: epidemiology and diagnosis

Lower gastrointestinal bleeding is one of the most common gastrointestinal indications for hospital admission, particularly in the elderly. Diverticulosis accounts for up to 50% of cases, followed by ischemic colitis and anorectal lesions. Though most patients stop bleeding spontaneously and have favorable outcomes, long-term recurrence is a substantial problem for patients with bleeding from diverticulosis and angiodysplasia. The management of LGIB is challenging because of the diverse range of bleeding sources, the large extent of bowel involved, the intermittent nature of bleeding, and the various complicated and often invasive investigative modalities. Advances in endoscopic technology have brought colonoscopy to the forefront of the management of LGIB. However, many questions remained to be answered about its usefulness in routine clinical practice. More randomized controlled trials comparing available diagnostic strategies for LGIB are needed.

Differential diagnosis of gastrointestinal bleeding

In this article, we review the many causes of gastrointestinal (GI) bleeding and discuss current strategies for rendering a specific diagnosis. Diagnostic tools considered in this review include: clinical assessment, upper endoscopy, colonoscopy, scintigraphy, and conventional arteriography as well as computed tomography angiography and magnetic resonance angiography. An algorithm for the diagnostic work-up of the patient with GI bleeding is included.

Small bowel metastases from primary carcinoma of the lung: presenting with gastrointestinal hemorrhage

Upper gastrointestinal system bleeding should be first taken into account when a patient complains of melena. On rare occasions, gastrointestinal bleeding may be due to primary or metastatic tumors of the gastrointestinal system. Here, we present a case in which the localization of bleeding was demonstrated by Tc-99m red blood cell labeled scintigraphy with the final diagnosis of metastases of non-small cell lung cancer to the small bowel.

Acute gastrointestinal bleeding

Radionuclide bleeding scintigraphy remains a simple yet powerful method of localizing sites of gastrointestinal hemorrhage and is most commonly performed today using the red blood cell technique. Radionuclide techniques for detecting bleeding remain safe, sensitive, and noninvasive. Based on several simple concepts, including the use of cine-mode imaging over the abdomen, it is possible to achieve excellent accuracy in localizing the site of bleeding. Studies often contain additional ancillary information, which is helpful for diagnosis and patient treatment.

Selective role of nuclear medicine in evaluating the acute abdomen

The imaging evaluation of the acute abdomen has clearly evolved with the introduction of high-resolution imaging techniques, such as CT, US, and MR imaging, leaving scintigraphic examinations an important, though selective, role based on their noninvasive, physiologic, and functional nature. Proper use of these examinations among all the diagnostic methods requires a good understanding of their strengths and limitations.

The clinical utility of nuclear medicine imaging for the detection of occult gastrointestinal haemorrhage

Acute gastrointestinal bleeding is often intermittent and the bleeding source may be difficult to locate, resulting in delay of potentially life-saving treatment. The aim of this study was to determine the clinical utility of 99mTc labelled red blood cell imaging and [99mTc]pertechnetate (Meckel's scan) imaging in a series of 137 patients admitted over a 5 year period to hospital for management of acute gastrointestinal bleeding. Of the 137 patients, 70 had positive 99mTc red blood cell studies. Eleven of 24 patients who had imaging performed beyond 3 h had positive scans that would otherwise have been missed. Only 47 patients had a definite final diagnosis at the time of hospital discharge, of which six were negative on 99mTc red blood cell imaging. The correct site of bleeding was localized in seven of 21 patients with foregut bleeding, and 15 of 20 patients with colonic bleeding. Endoscopy yielded a diagnosis in 13 of the 47 patients (28%). Eleven patients had Meckel's scans but all were negative. Angiography was diagnostic in one of 17 patients studied. 99mTc red blood cell imaging is a useful test in the management of acute gastrointestinal bleeding. Imaging beyond 3 h may further improve the bleeding detection rate. This test, however, may be an unreliable means of localization of bleeding, particularly in the foregut.