Utility of SPECT/CT with Meckel's scintigraphy

The significance of Meckel's scan in pediatric gastrointestinal bleeding cases: A case report

Meckel's diverticulum is the most prevalent congenital anomaly of the gastrointestinal tract, identified in 2% of the population according to autopsy studies. Most patients remain asymptomatic throughout their lives and are typically diagnosed when complications arise. The diagnosis can be challenging, but imaging is crucial for promptly identifying and distinguishing it from other conditions that have similar clinical manifestations. A 13-year-old male was admitted with a 5-day history of rectal bleeding. The patient continued to experience painless gastrointestinal bleeding, indicating the performance of a Tc-99m pertechnetate scintigraphy or Meckel's scan. Planar images revealed focal uptake within the right hemiabdomen, suggestive of the presence of a Meckel's diverticulum. Subsequent laparotomy surgery confirmed the presence of a Meckel's diverticulum located 50 cm from the ileocecal valve. Histopathological examination of the resected specimen confirmed Meckel's diverticulum with ectopic gastric mucosa. This patient with Meckel's diverticulum exhibited minimal abdominal symptoms, and there were no other complications such as intussusception, which could lead to bowel obstruction. Technetium-99m pertechnetate scintigraphy is a common method for evaluating children with unexplained gastrointestinal tract bleeding. SPECT/CT fusion imaging enables the simultaneous fusion of functional and anatomical information, preventing false-negative scintigraphy examinations. Its capability to precisely localize activity in abnormal structures contributes to accurate scan interpretation. Complications of Meckel's diverticulum are uncommon and pose a diagnostic challenge. Through comprehensive history-taking, physical examination, and nuclear imaging, the diagnosis can be identified, and surgical intervention can be performed to achieve the best possible outcome for the patient.

Meckel diverticulum scintigraphy: technique, findings and diagnostic pitfalls

Meckel diverticulum, the most common congenital anomaly of the gastrointestinal tract, results from the aberrant involution of the omphalomesenteric duct and accounts for more than 50% of unexplained lower gastrointestinal bleeding in the pediatric population. The most accurate imaging tool to identify a Meckel diverticulum containing ectopic gastric mucosa is the Technetium-99m pertechnetate Meckel scan, a scintigraphic study with a reported accuracy of 90% in the pediatric population. In addition to depicting a Meckel diverticulum with ectopic gastric mucosa, careful attention to the normal biodistribution of the radiotracer can lead to the identification of unexpected pathology with implications for patient management. This article serves to review the embryological origin and anatomical features of Meckel diverticulum, highlight the role of scintigraphy in evaluating Meckel diverticulum, and discuss the proper imaging technique when performing this test. We will focus on pitfalls that can lead to an erroneous diagnosis as well as incidental findings that can affect patient management.

Excreted 99m Tc-Pertechnetate in a Renal Pelvis as a Potential False Positive in a Meckel's Scan

ABSTRACT

A 14-year-old girl presented with right lower quadrant pain. A 99m Tc-pertechnetate scan with SPECT/CT was performed to exclude a Meckel's diverticulum. The images demonstrated focal tracer uptake in the right midabdomen, which appeared early and decreased over time. However, SPECT/CT revealed that this uptake corresponded to the right renal pelvis, which was located more inferior than expected. This case emphasizes the importance of recognizing anatomic variants that may cause focal tracer uptake, as well as leveraging an understanding of tracer kinetics to inform a diagnosis.

An Atypical Case of Meckel's Diverticulum Assessed by SPECT/CT Imaging

ABSTRACT

A 17-year-old adolescent boy presented with multiple episodes of hematochezia. After a negative 99mTcO4 scan, upper endoscopy, colonoscopy, and CT angiography, the patient underwent a second 99mTcO4 scan with ranitidine. The anterior images demonstrated a faint, delayed focus of uptake in the midabdomen without correlate on lateral projections. SPECT/CT was performed for localization with the focus of activity seen in an anterior loop of distal small bowel adjacent to the umbilicus. The patient subsequently underwent diagnostic laparoscopy and resection of the diverticulum with postoperative resolution of the symptoms.

Meckel’s diverticulum diagnosis by video capsule endoscopy: A case report and review of literature

BACKGROUND

Meckel’s diverticulum (MD) occurs predominantly in children and adolescents. It is rarely diagnosed in adults. Preoperative diagnosis is difficult due to low sensitivity of the radiological imaging studies. The role of video capsule endoscopy (VCE) in the diagnosis of MD is unknown, and the endoscopic patterns are not defined. We will describe four of our cases of MD evaluated with VCE and make a review of the literature focusing on the endoscopic characteristics.

CASE SUMMARY

We present four cases of MD confirmed by surgery. They were all adult males with ages going from 18 to 50 years, referred to our service from 2004 to 2018, due to obscure gastrointestinal bleeding (OGIB). They had a history of 1 mo to 10 years of overt and occult bleeding episodes. Laboratory blood test showed an iron-deficiency anemia from 4 to 9 g/dL of hemoglobin that required multiple hospitalizations and blood transfusions in all cases. Repeated upper digestive endoscopies and colonoscopies were negative. Small bowel was examined with VCE, which revealed double lumen images in all cases, one with polyps and three with circumferential ulcers in the diverticulum. However, based on VCE findings, preoperative diagnosis of MD was suggested only in two patients. Capsule was retained in one patient, which was recovered with surgery. The anatomopathological report revealed ulcerated ectopic gastric mucosa in all cases.

CONCLUSION

VCE is useful for the diagnosis of MD. However, endoscopic characteristics must be recognized in order to establish preoperative diagnosis.

Spontaneous perforation and intraabdominal abscess due to Meckel's diverticulum revealed on SPECT/CT with 99m-technetium pertechnetate: A case report

RATIONALE

Meckel's diverticulum (MD) is common congenital abnormality of gastrointestinal tract, only about 6.4% of patients become symptomatic. A smaller minority develop potential fatal complications such as hemorrhage, perforation, abscess, and bowel obstruction.

PATIENT CONCERNS

A 15-year-old boy with history of appendicitis was admitted due to worsening abdominal pain and nausea for 1 day. The physical examination showed the abdomen was soft, with the diffuse tenderness to palpation and voluntary guarding.

DIAGNOSIS

Abdominal computed tomography showed a probable MD in the distal ileum. Single photon emission computed tomography/computed tomography (SPECT/CT) fusion imaging revealed the focal concentration at the right lower quadrant of abdomen region.

INTERVENTION

After the initial management including antibiotic administration and intravenous fluid resuscitation, MD with perforation and localized suppurative peritonitis was confirmed in surgery. The patient underwent a diverticulectomy. Histological examination was confirmed as MD with focal heterotopic gastric tissue.

OUTCOMES

After surgery, the patient had uneventful recovery during 3 months follow-up.

LESSONS

Spontaneous perforation and intraabdominal abscess due to MD is very rare. Accurate diagnosis of MD remains challenging as clinical symptoms from these complications occur nonspecifically. SPECT/CT fusion imaging is critical for prompt recognition and accurate diagnosis in the successful management of this rarely life-threating complication.

Umbilical Varices: A Potential Pitfall in Gastrointestinal Bleed Scintigraphy Interpretation

Tc-99m labeled red blood cell (RBC) scintigraphy is commonly used in the evaluation of acute gastrointestinal (GI) bleeding. On Tc-99m RBC studies, GI bleeding is seen as an initial focus of increased radiotracer activity that on subsequent images increases in intensity and changes position in a pattern that confirms to segments of bowel. We report a case of a patient with multiple episodes of GI bleeding referred to detect the source of bleeding. A Tc-99m labeled RBC scan was performed and the findings showed a focal abnormal hot spot in the mid quadrant of the abdomen, seen promptly in initial dynamic images. Subsequent static and single-photon emission computed tomography-CT (SPECT-CT) images found it to be umbilical varices. Most varices fill promptly as in this case and should not be misinterpreted as a focus of hemorrhage. SPECT-CT should be used in such cases so that that false-positive interpretation can be avoided.

Incremental value of SPECT/CT in detection of Meckel's diverticulum in a 10-year-old child

Introduction

Meckel’s diverticulum is a common congenital abnormality of gastrointestinal tract in children. Planar scintigraphy using Technetium-99m pertechnetate is widely used in the diagnosis of Meckel’s diverticulum. Single photon emission computed tomography/computed tomography (SPECT/CT) fusion imaging may help to locate the Meckel’s diverticulum lesion. We now present a Meckel’s diverticulum case which tends to be missed.

Case description

The patient was diagnosed with Mecke’s diverticulum by planar scintigraphy in 2007. After seven years, a recurrence of hematochezia made the patient undergo planar scintigraphy again. However, the concentration on planar image was located at the right kidney level, we could not determine whether it was caused by physiological uptake of the right kidney or by an ectopic gastric mucosa. Using SPECT/CT technique, we confirmed that the lower part of the concentration was from a Meckel’s diverticulum from the small intestine based on the functional and anatomical information together.

Discussion and Evaluation

For concentrations about the kidney level, planar scintigraphy is not enough to be diagnostic of Meckel’s diverticulum. SPECT/CT imaging may be beneficial for a definitive diagnosis. Also, fusion images may provide precise localization of the lesion. To make sure that patients obtain optimal benefit from a SPECT/CT examination, we have to balance the priority between information of anatomic location and avoiding redundant radiation to the patients.

Conclusions

Our case study suggest that for cases with ambiguous planar scintigraphy images, SPECT/CT imaging should be performed to obtain a definitive diagnosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-2928-4) contains supplementary material, which is available to authorized users.

The value of repeat scintigraphy in patients with a high clinical suspicion for Meckel diverticulum after a negative or equivocal first Meckel scan

BACKGROUND

Technetium (99m)Tc-pertechnetate is the most common and accurate noninvasive method of preoperative investigation for Meckel diverticulum. Despite introducing various methods to increase the sensitivity of the study, there are many case reports of false-negative Meckel scans. A repeat scan is sometimes requested in patients with a high suspicion for Meckel diverticulum and negative or equivocal first Meckel scan.

OBJECTIVES

The purpose of this retrospective study is to evaluate the value of repeat scintigraphy for these patients.

MATERIALS AND METHODS

Seven hundred fifty-three Meckel scans were recorded retrospectively. In 33 cases (22 male and 11 female; mean age: 6.8 years), the Meckel scintigraphy was repeated either due to a high clinical suspicion of Meckel diverticulum and a negative study (n = 21) or due to equivocal findings in the first scan (n = 12). The study was interpreted as positive if an abnormal focal activity was identified in the abdomen and pelvis during the procedure. The results were correlated with pathology and clinical symptoms.

RESULTS

Seven out of 12 (58%) equivocal studies were positive on the second study. Six of them were proven to be positive at operation (confirmed by pathology) while one of them was negative on laparoscopy. From 21 negative first scans with a high suspicion for Meckel diverticulum, three (14%) were positive on the second study. All three were proven to be Meckel diverticulum on pathology.

CONCLUSION

Repeat Meckel scans in patients with equivocal findings on the first study or a negative result with a high clinical suspicion for a Meckel diverticulum are useful especially in cases in which the first study had been done without appropriate preparation.

Rescue Radioguided Laparoscopy Surgery for Meckel's Diverticulum: Technical Notes

The extirpation of Meckel's diverticulum (MD) via conventional or laparoscopic surgery is the definitive treatment. However, certain circumstances may modify or alter this situation and require the application of exceptional measures.We report a case under our observation who previously had an exploratory abdominal laparotomy for a suspected MD; however, the findings were negative. At that time, the diagnosis was established based on low-level gastrointestinal bleeding and isotopic tests that confirmed the existence of the diverticulum. Given the findings of gamma-graphic exploration and the previous negative surgical exploration, a decision was made to remove the lesion by laparoscopic radioguided surgery.The patient underwent bilateral laparoscopic radioguided surgery using a gamma radiation detection probe. The exploration of the abdominal cavity noted the existence of the diverticulum about 60 to 70  cm from the ileocecal valve. In this way, it was possible to proceed with the resection of the bowel loop and perform an intracorporeal anastomosis termino lateral. The postoperative course was uneventful, and the patient was discharged on the fifth postoperative day.We believe that the combination of radioguided surgery and single photon emission computed tomography/computed tomography could be useful for treating lesions in locations that are surgically difficult because of the characteristics of the lesion itself or the peculiarities of an individual patient.

Radioguided surgery in Meckel's diverticulum

We analyze the case of a patient with intermittent episodes of lower gastrointestinal bleeding and suspected Meckel's diverticulum, whose presence was confirmed by (99m)Tc-pertechnetate scintigraphy. A previous exploratory laparotomy had been performed without finding the diverticulum. In spite of years of medical treatment, the patient presented a new episode of lower gastrointestinal bleeding with normal colonoscopy. A new (99m)Tc-pertechnetate scintigraphy (including SPECT/CT) was performed and allowed the anatomical location of a Meckel's diverticulum and enabled its removal by laparoscopic radioguided surgery. The introduction of SPECT/CT in the scintigraphic diagnostic protocol in Meckel's diverticulum increases diagnostic safety and improves lesion location. Furthermore, it favors the performance of radioguided surgery and facilitates the lesion resection, particularly when the patient has suffered previous abdominal surgery, with a more conservative procedure, reducing the morbidity associated with the surgical procedure.

Radionuclide small intestine imaging

The aim of this overview article is to present the current possibilities of radionuclide scintigraphic small intestine imaging. Nuclear medicine has a few methods-scintigraphy with red blood cells labelled by means of (99m)Tc for detection of the source of bleeding in the small intestine, Meckel's diverticulum scintigraphy for detection of the ectopic gastric mucosa, radionuclide somatostatin receptor imaging for carcinoid, and radionuclide inflammation imaging. Video capsule or deep enteroscopy is the method of choice for detection of most lesions in the small intestine. Small intestine scintigraphies are only a complementary imaging method and can be successful, for example, for the detection of the bleeding site in the small intestine, ectopic gastric mucosa, carcinoid and its metastasis, or inflammation. Radionuclide scintigraphic small intestine imaging is an effective imaging modality in the localisation of small intestine lesions for patients in whom other diagnostic tests have failed to locate any lesions or are not available.

Less commonly used and emerging clinical applications of SPECT-CT in benign and malignant disease

The emergence of hybrid imaging, combining anatomical computed tomography (CT) and functional single-photon emission computed tomography (SPECT), has greatly expanded the armoury available to image disease. Integrated SPECT-CT is a dual-modality technique, which improves the sensitivity and specificity of existing radionuclide studies and enables characterization of equivocal findings detected by conventional imaging. There is a wide range of established and emerging clinical applications for SPECT-CT, which were reviewed in detail at a symposium organized by the British Institute of Radiology in March 2012. A series of articles were commissioned as an adjunct to the symposium and to raise awareness of the clinical utility of this technique. The focus of this article is on less commonly used and emerging clinical applications of hybrid SPECT-CT in a spectrum of benign and malignant conditions. The article will illustrate the incremental value of the technique in a variety of clinical applications.

False positive GI bleed on Tc-99m RBC scintigraphy due to ileal varices

Tc-99m labeled RBC scintigraphy is commonly employed in the evaluation of acute gastrointestinal bleeding. On Tc-99m RBC studies gastrointestinal bleeding is seen as an initial focus of increased radiotracer activity that on subsequent images increases in intensity and changes position in a pattern that conforms to segments of bowel. We report a case of a patient with multiple episodes of hematochezia that presented with lower gastrointestinal hemorrhage. A Tc-99m labeled RBC scan was performed and the findings suggested a GI bleed. However, subsequent angiography revealed prominent ileal varices simulating an acute bleed. Although most varices fill promptly and should not be misinterpreted as a focus of hemorrhage, slow filling varices can simulate an acute bleed and lead to a false positive interpretation.

Advances in small bowel imaging

The small intestine has been difficult to examine by traditional endoscopic and radiologic techniques. Within the past 10 years, advances have led to an explosion of technologies that facilitate examination of the entire small intestine. Wireless video capsule endoscopy, deep enteroscopy using balloon-assisted or spiral techniques, computer tomography (CT) and magnetic resonance (MR) enterography have facilitated the diagnosis, monitoring, and management of patients with small intestinal diseases. These technologies are complementary, each with its advantages and limitations. Capsule endoscopy provides a detailed view of the mucosal surface and has excellent patient acceptance, but does not allow therapeutics. Deep enteroscopy allows careful inspection of the mucosa and therapeutics, but is time consuming and invasive. Enterography (CT or MR) allows examination of the small bowel wall and surrounding structures. The initial best test for detecting small intestinal disease depends on clinical presentation and an astute differential diagnosis.