SPECT-CT of Meckel Diverticulum

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 with polypoid hyperplasia of ectopic gastric mucosa diagnosed by double-balloon enteroscopy and single-photon emission computed tomography/computed tomography

Meckel’s diverticulum (MD) is a relatively common true congenital diverticulum on the ileum. Bleeding caused by polypoid hyperplasia of ectopic gastric mucosa in MD is rare. A 14-year-old Chinese boy presented with intermittent melena and haematochezia for 1 month. Laboratory data showed normocytic anaemia. Gastroscopic findings were normal. The patient underwent exploratory laparotomy without bowel preparation on day 2 because of sudden haematochezia and decreased haemoglobin. Intraoperative colonoscopy revealed inflammatory changes in the terminal ileal mucosa with diffuse haemorrhage. Melena with decreased haemoglobin recurred 20 days after the first operation. Computed tomography (CT) and angiography revealed a tubular lesion that was localised in the right lower abdominal quadrant. Single-photon emission computed tomography/computed tomography (SPECT/CT) fusion imaging with 99m-technetium pertechnetate confirmed moderately increased uptake in the distal ileum. Retrograde double-balloon enteroscopy (DBE) showed a diverticulum with prominent mucosal polypoid hyperplasia at an insertion depth of 100 cm from the anastomotic stoma. Diverticulectomy and end-to-end anastomosis were performed, and MD was confirmed by a histopathological examination. The patient’s postoperative recovery was uneventful during the 2-month follow-up. MD with polypoid hyperplasia of ectopic gastric mucosa is rare. Complementary use of DBE and SPECT/CT can accurately diagnose MD by providing anatomical and functional information.

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.

Tubular Intestinal Duplication Harboring Gastric Ectopia Accurately Diagnosed by Tc-99m Pertechnetate Single-photon Emission Computed Tomography/Computed Tomography Meckel's Scan

A 7-year-old girl with an episode of hematochezia and melena, suspicious for bleeding Meckel's diverticulum, was referred for a Tc-99m pertechnetate Meckel's scan. On dynamic planar scan, apart from prompt gastric visualization an oval-shaped, area of inhomogeneous tracer uptake was observed in the left lower quadrant of the abdomen. Subsequent single-photon emission computed tomography/computed tomography localized this to intestinal lumen, thus establishing the diagnosis of intestinal duplication (ID) with functional gastric mucosa. Surgical exploration confirmed the presence of a tubular ID in a distance of 1.5 m from the ileocecal valve and pathologic examination showed gastric mucosa lining the lumen of the duplication.

Reminiscing on Remnants: Imaging of Meckel Diverticulum and Its Complications in Adults

OBJECTIVE

Meckel diverticulum may become symptomatic if it is complicated by hemorrhage, intestinal obstruction, diverticulitis, or tumor. Although classically described in children, it is often missed in adults because of lack of suspicion and difficulty in detection. The purpose of this article is to review the imaging findings and management of Meckel diverticulum and its complications.

CONCLUSION

Although it is infrequently encountered incidentally, Meckel diverticulum should be considered especially when interpreting examinations for abdominal pain, small-bowel obstruction, and gastrointestinal bleeding.

Gastrointestinal Bleeding Scintigraphy in the Early 21st Century

Gastrointestinal bleeding scintigraphy performed with (99m)Tc-labeled autologous erythrocytes or historically with (99m)Tc-sulfur colloid has been a clinically useful tool since the 1970s. This article reviews the history of the techniques, the different methods of radiolabeling erythrocytes, the procedure, useful indications, diagnostic accuracy, the use of SPECT/CT and CT angiography to evaluate gastrointestinal bleeding, and Meckel diverticulum imaging. The causes of pediatric bleeding are discussed by age.

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.

Potential false-positive meckel scan due to displaced kidney caused by recurrent retroperitoneal teratoma

We report the findings of a Meckel scan in a 19-year-old patient treated for retroperitoneal teratoma with intermittent tarry stool for 1 month. Two focal stases of radioactivity in the right upper quadrant of the abdomen were noted. SPECT/CT for localization revealed that these 2 foci were within the displaced right kidney along with an adjacent bulky retroperitoneal mass. The patient subsequently underwent surgery, and histopathological studies confirmed recurrent teratoma. Two foci of increased radioactivity instead of 1 may have provided hints for the physiological characteristics of such lesions.

A review on the clinical uses of SPECT/CT

In the era when positron emission tomography (PET) seems to constitute the most advanced application of nuclear medicine imaging, still the conventional procedure of single photon emission computed tomography (SPECT) is far from being obsolete, especially if combined with computed tomography (CT). In fact, this dual modality imaging technique (SPECT/CT) lends itself to a wide variety of useful diagnostic applications whose clinical impact is in most instances already well established, while the evidence is growing for newer applications. The increasing availability of new hybrid SPECT/CT devices with advanced technology offers the opportunity to shorten acquisition time and to provide accurate attenuation correction and fusion imaging. In this review we analyse and discuss the capabilities of SPECT/CT for improving sensitivity and specificity in the imaging of both oncological and non-oncological diseases. The main advantages of SPECT/CT are represented by better attenuation correction, increased specificity, and accurate depiction of the localization of disease and of possible involvement of adjacent tissues. Endocrine and neuroendocrine tumours are accurately localized and characterized by SPECT/CT, as also are solitary pulmonary nodules and lung cancers, brain tumours, lymphoma, prostate cancer, malignant and benign bone lesions, and infection. Furthermore, hybrid SPECT/CT imaging is especially suited to support the increasing applications of minimally invasive surgery, as well as to precisely define the diagnostic and prognostic profile of cardiovascular patients. Finally, the applications of SPECT/CT to other clinical disorders or malignant tumours is currently under extensive investigation, with encouraging results in terms of diagnostic accuracy.

Utility of SPECT/CT with Meckel's scintigraphy

Meckel's diverticulum is a relatively common source of gastrointestinal tract morbidity in children. Individuals may present with symptoms of lower gastrointestinal tract bleeding, bowel obstruction or diverticulitis. Technetium-99 m pertechnetate scintigraphy is used to demonstrate those Meckel's diverticula that contain heterotopic gastric mucosa. We present a case of an adolescent male patient with rectal bleeding and suspected Meckel's diverticulum where the use of SPECT/CT fusion imaging provided valuable diagnostic information and prevented a false-negative study.

SPECT/CT imaging: clinical utility of an emerging technology

Single-photon emission computed tomography (SPECT) has been a mainstay of nuclear medicine practice for several decades. More recently, combining the functional imaging available with SPECT and the anatomic imaging of computed tomography (CT) has gained more acceptance and proved useful in many clinical situations. Most vendors now offer integrated SPECT/CT systems that can perform both functions on one gantry and provide fused functional and anatomic data in a single imaging session. In addition to allowing anatomic localization of nuclear imaging findings, SPECT/CT also enables accurate and rapid attenuation correction of SPECT studies. These attributes have proved useful in many cardiac, general nuclear medicine, oncologic, and neurologic applications in which the SPECT results alone were inconclusive. Optimal clinical use of this rapidly emerging imaging modality requires an understanding of the fundamental principles of SPECT/CT, including quality control issues as well as potential pitfalls and limitations. The long-term clinical and economic effects of this technology have yet to be established.