Pharmacologic interventions in nuclear radiology: indications, imaging protocols, and clinical results

Tc-99m scan for pediatric bleeding Meckel diverticulum:a systematic review and meta-analysis

OBJECTIVE

Meckel diverticulum (MD) is a common malformation of the digestive tract, often accompanied by serious complications. It is important to find safe and effective diagnostic methods for screening MD. The aim of this study was to evaluate the effectiveness of a technetium-99m (Tc-99m) scan for pediatric bleeding MD.

METHODS

The authors conducted a systematic review of studies published in PubMed, Embase, and Web of Science before 1 January 2023. Studies based on PICOS were included in this systematic review. The flow chart was made by PRISMA software. The quality of included studies was assessed by RevMan5 software (QUADAS-2: Quality Assessment of Diagnostic Accuracy Studies-2). The sensitivity, specificity, and other measurements of accuracy were pooled using Stata/SE 12.0 software.

RESULTS

Sixteen studies with 1115 children were included in this systematic review. A randomized-effects model was used for the meta-analysis because of significant heterogeneity. The combined sensitivity and specificity were 0.80 [Confidence Interval (95% CI, 0.73-0.86) and 0.95 (95% CI, 0.86-0.98)], respectively. The area under the curve (AUC) was 0.88 (95% CI, 0.85-0.90). Publication bias (Begg's test p = 0.053) was observed.

CONCLUSION

Tc-99m scan has high specificity, but moderate sensitivity, which is always influenced by some factors. Hence, the Tc-99m scan has some limitations in the diagnosis of pediatric bleeding MD.

Pharmacology, Part 4: Nuclear Cardiology

Pharmacology principles provide key understanding that underpins the clinical and research roles of nuclear medicine practitioners in nuclear cardiology. The scope of practice of the nuclear medicine technologist demands knowledge and understanding of indications, contraindications, warnings, precautions, proper use, drug interactions, and adverse reactions for each medication to be used. This article is the fifth in a series of articles that aims to enhance the understanding of pharmacologic principles relevant to nuclear medicine. This article will build on the introductory concepts, terminology, and principles of pharmacology explored in the first 2 articles in the series. Specifically, this article will focus on the pharmacologic principles and complex relationship associated with interventional, adjunctive, and cessation medications in nuclear cardiology. Future articles will address the pharmacology related to the emergency crash cart and contrast medium associated with CT and MRI.

Pharmacology, Part 3B: Less Commonly Used Interventional Medications and Adjunctive Medications in General Nuclear Medicine

The understanding of key principles in pharmacology is essential to the clinical and research nuclear medicine practitioner. The scope of practice of the nuclear medicine technologist requires understanding of the indications, contraindications, warnings, precautions, proper use, drug interactions, and adverse reactions for interventional and adjunctive medications. This article is the companion to the third in a series of articles that aims to enhance the understanding of pharmacologic principles relevant to nuclear medicine. This article will build on the introductory concepts, terminology, and principles of pharmacology explored in previous articles in the series. Specifically, this article will focus on the pharmacologic principles associated with less commonly used interventional medications and adjunctive medications encountered in general nuclear medicine practice. Future articles will address the pharmacology related to nuclear cardiology, the emergency crash cart, and contrast media associated with CT and MRI.

Magnetic Particle Imaging for Highly Sensitive, Quantitative, and Safe in Vivo Gut Bleed Detection in a Murine Model

Gastrointestinal (GI) bleeding causes more than 300 000 hospitalizations per year in the United States. Imaging plays a crucial role in accurately locating the source of the bleed for timely intervention. Magnetic particle imaging (MPI) is an emerging clinically translatable imaging modality that images superparamagnetic iron-oxide (SPIO) tracers with extraordinary contrast and sensitivity. This linearly quantitative modality has zero background tissue signal and zero signal depth attenuation. MPI is also safe: there is zero ionizing radiation exposure to the patient and clinically approved tracers can be used with MPI. In this study, we demonstrate the use of MPI along with long-circulating, PEG-stabilized SPIOs for rapid in vivo detection and quantification of GI bleed. A mouse model genetically predisposed to GI polyp development (ApcMin/+) was used for this study, and heparin was used as an anticoagulant to induce acute GI bleeding. We then injected MPI-tailored, long-circulating SPIOs through the tail vein, and tracked the tracer biodistribution over time using our custom-built high resolution field-free line (FFL) MPI scanner. Dynamic MPI projection images captured tracer accumulation in the lower GI tract with excellent contrast. Quantitative analysis of the MPI images show that the mice experienced GI bleed rates between 1 and 5 μL/min. Although there are currently no human scale MPI systems, and MPI-tailored SPIOs need to undergo further development and evaluation, clinical translation of the technique is achievable. The robust contrast, sensitivity, safety, ability to image anywhere in the body, along with long-circulating SPIOs lends MPI outstanding promise as a clinical diagnostic tool for GI bleeding.

Unusual presentation of obscure Meckel diverticulum treated with robot-assisted diverticulectomy: A case report

INTRODUCTION

Meckel diverticulum (MD) is the most common congenital abnormality of gastrointestinal tract. Tough believed to occur in 2% of population, most of them remain veiled because majority are clinically asymptomatic and remain obscure in radiological examination.

CLINICAL FINDINGS AND DIAGNOSIS

A 26-year-old male with episodic black colored stool since last 10 years. Tough symptomatic, diagnosis of pathological lesion, and the bleeding site could not be established with any of the sophisticated diagnostic technique. After 10 years, it was finally diagnosed as MD with careful observation of bowel loops on computed tomography enterography (CTE) where remnant of vitelline vessel and hyper-enhancing nodule are seen along the wall of diverticular loop.

INTERVENTIONS AND OUTCOMES

The patient underwent robot assisted laparoscopic surgery with excision of diverticular loop. To the best of our knowledge, this robot-assistant Meckel diverculectomy is probably the first reported surgical procedure in PubMed. Follow-up for 3 month showed no complication or recurrence.

CONCLUSION

Every case is unique and we must be aware and remain alert in tracing the possible morphological variation of the case. Here, we present one unique but rare feature of MD, which helped us in making diagnosis.

Morphine three-dimensional T1 gadoxetate MR cholangiography of potential living related liver donors

PURPOSE

To assess low-dose morphine for distension and improved visualization of intrahepatic bile ducts on T1 MR cholangiography (MRC) in preoperative imaging of potential liver donors.

MATERIALS AND METHODS

Sixty-nine consecutive potential living related liver donors (mean age, 39 years; age range, 20 to 59 years) referred for pre-transplant MRI evaluation were evaluated without (n=30) or with (n=39) intravenous morphine injection (0.04 mg/kg). Morphine was injected pre-MRI while establishing intravenous access to allow ∼1 h for biliary distension before T1 MRC. Three radiologists reviewed intrahepatic biliary branch order visualization, common bile duct (CBD) diameter, and overall image quality. In 25 patients undergoing liver donation surgery, T1 MRC findings were correlated with intraoperative findings. This retrospective study was approved by the institutional review board.

RESULTS

Biliary visualization was improved post-morphine administration with biliary duct branch order visualization score of 3.2 and 3.3 at 45 and 60 min, respectively, compared with 2.7 without morphine (P<0.002); CBD diameter measured 5.3 and 5.5 versus 4.1 mm (P<0.005), and overall image quality score was 2.4 and 2.6 versus 1.8 (P<0.0006). Operative notes confirmed T1 MRC findings in 6/11 donors without morphine and 14/14 donors with morphine.

CONCLUSION

Intravenous low-dose morphine distends and improves visualization of bile ducts on T1 gadoxetate MRC.

Functional evaluation of cystic duct patency with Gd-EOB-DTPA MR imaging: an alternative to hepatobiliary scintigraphy for diagnosis of acute cholecystitis?

PURPOSE

To determine if MR cholangiography with Gd-EOB-DTPA can be used to assess cystic duct patency and to establish normal time range for reflux of contrast material into the cystic duct/gallbladder.

MATERIALS AND METHODS

This retrospective study is HIPAA-compliant and IRB-approved with waiver for informed consent granted. From September 2008 to June 2009, 300 patients who underwent Gd-EOB-DTPA-enhanced MR imaging for various clinical indications, not specifically limited to evaluation for acute cholecystitis, were identified. 112 patients were excluded: prior cholecystectomy (n = 93), severe technical limitations (n = 9), or absence of appropriate clinical follow-up (n = 10). 188 total patients (82 male, 106 female, mean age 51.0 years) were included in the final dataset. Time between contrast administration and contrast reflux into the cystic duct/gallbladder on delayed phase imaging was measured.

RESULTS

Reflux of contrast into the gallbladder was identified in 130/188 patients (69.1%) on delayed phase imaging. Average time to gallbladder reflux was 15:24 ± 5:51 minutes (range: 6:01-41:05 min). 58/188 patients (30.9%) demonstrated no reflux of contrast into the gallbladder at time of final delayed phase images. Of 58 patients who demonstrated no reflux into cystic duct/gallbladder, 15 patients demonstrated no extrahepatic biliary excretion, limiting evaluation of cystic duct patency. A total of 173 patients demonstrated biliary excretion of contrast with 76% overall sensitivity of detection of cystic duct patency.

CONCLUSION

MR cholangiography with hepatobiliary MR contrast agents such as Gd-EOB-DTPA can demonstrate cystic duct patency with high sensitivity. MR protocols can be designed within a clinically feasible timeframe to optimize diagnosis of acute cholecystitis.

Dual-energy CT-cholangiography in potential donors for living-related liver transplantation: improved biliary visualization by intravenous morphine co-medication

PURPOSE

To prospectively evaluate whether intravenous morphine co-medication improves bile duct visualization of dual-energy CT-cholangiography.

MATERIALS AND METHODS

Forty potential donors for living-related liver transplantation underwent CT-cholangiography with infusion of a hepatobiliary contrast agent over 40 min. Twenty minutes after the beginning of the contrast agent infusion, either normal saline (n=20 patients; control group [CG]) or morphine sulfate (n=20 patients; morphine group [MG]) was injected. Forty-five minutes after initiation of the contrast agent, a dual-energy CT acquisition of the liver was performed. Applying dual-energy post-processing, pure iodine images were generated. Primary study goals were determination of bile duct diameters and visualization scores (on a scale of 0 to 3: 0--not visualized; 3--excellent visualization).

RESULTS

Bile duct visualization scores for second-order and third-order branch ducts were significantly higher in the MG compared to the CG (2.9±0.1 versus 2.6±0.2 [P<0.001] and 2.7±0.3 versus 2.1±0.6 [P<0.01], respectively). Bile duct diameters for the common duct and main ducts were significantly higher in the MG compared to the CG (5.9±1.3 mm versus 4.9±1.3 mm [P<0.05] and 3.7±1.3 mm versus 2.6±0.5 mm [P<0.01], respectively).

CONCLUSION

Intravenous morphine co-medication significantly improved biliary visualization on dual-energy CT-cholangiography in potential donors for living-related liver transplantation.

Morphine- and glucagon-augmented magnetic resonance cholangiopancreatography to evaluate living liver donors

The purpose of this study was to investigate the effectiveness of the combined use of intravenous morphine and intramuscular glucagon in improving magnetic resonance cholangiopancreatography (MRCP) image quality in donors for living-related liver transplantation. Sixteen healthy donor candidates underwent an MRCP study. Coronal, single-shot, fast spin-echo, heavily T2-weighted dynamic MRCP images were obtained before and 3 minutes after the intravenous administration of morphine HCl with a dose of 0.04 mg/kg. Thirty minutes after the injection of morphine, intramuscular glucagon was used. Another MRCP image of the same pulse sequence was generated 15 minutes after the injection of glucagon with a dose of 1 mg. The diameter, signal intensity, and number of branches of bile ducts in MRCP images taken immediately before and after the injection of morphine and after the injection of glucagon (plus delayed morphine effects) were compared and analyzed. In all 16 donor candidates, the diameters of the right and left hepatic ducts, common bile duct, and main pancreatic duct were significantly increased (P < 0.05) in the MRCP images taken 3 minutes after the injection of morphine and 15 minutes after the injection of glucagon (plus delayed morphine effects) in comparison with MRCP images taken before any drug administration. The qualitative grading scores of the signal intensity and order of branches of bile ducts revealed improvements in the MRCP images after the injection of glucagon (plus delayed morphine effects; P < 0.05). In conclusion, combining the intravenous administration of low-dose morphine and the intramuscular use of glucagon before MRCP examination improves the visualization of the nondilated biliary ductal anatomy, which is important for the preoperative biliary evaluation of donor candidates for living-related liver transplantation.

Radiological features of Meckel's diverticulum and its complications

Meckel's diverticulum is the most common congenital abnormality of the small bowel. The majority of patients with this anomaly will remain asymptomatic; however, several complications may occur, including obstruction, intussusception, perforation, diverticulitis, and gastrointestinal haemorrhage. These complications may produce a variety of different clinical features and radiological appearances. The purpose of this article is to review the potential imaging manifestations of Meckel's diverticulum and its complications and discuss the advantages and disadvantages of the imaging techniques available.

Increased urinary N-acetyl-beta-D-glucosaminidase activity in children with hydronephrosis

OBJECTIVE

Hydronephrosis leads to deterioration of renal function. As urinary N-acetyl-beta-D-glucosaminidase (U-NAG) activity is considered a sensitive marker of renal tubular impairment, our aim was to measure U-NAG in children with hydronephrosis and to look for a relationship among selected clinical parameters.

MATERIALS AND METHODS

We studied 31 children (22 boys and 9 girls, mean age 2.3 +/- 2.5 years) with hydronephrosis grade 1-4 that had U-NAG/creatinine ratio (U-NAG/Cr) measured.

RESULTS

The U-NAG/Cr was significantly higher in patients with hydronephrosis compared to reference data (p = 0.002). There was no difference in U-NAG/Cr between children with unilateral and bilateral hydronephrosis (p = 0.51). There was no significant difference in U-NAG/Cr between children with grades 1-3 (pooled data) and grade 4, respectively (p = 0.89). There was no correlation between U-NAG/Cr and the grade of hydronephrosis (r = 0.01).

CONCLUSIONS

U-NAG/Cr is increased in children with hydronephrosis grade 1-4, and there is no relationship with the grade of hydronephrosis. U-NAG is a useful marker of renal tubular dysfunction, however its relationship with the degree of kidney damage in patients with hydronephrosis should be considered as doubtful.

MR cholangiopancreatography: improved ductal distention with intravenous morphine administration

Magnetic resonance (MR) cholangiopancreatography has proved a robust and noninvasive imaging modality for evaluating the biliary and pancreatic ducts without the use of ionizing radiation. Although MR cholangiopancreatography reliably depicts the main extrahepatic and intrahepatic bile ducts, it does not depict the segmental intrahepatic ducts unless they are dilated. The segmental ducts are difficult to visualize with MR cholangiopancreatography because of their small caliber and the limited spatial resolution and signal-to-noise ratio achievable with standard MR pulse sequences. However, visualization of the normal (ie, nondistended) biliary system is necessary for the evaluation of donor candidates for living related liver transplantation. Because of the prevalence of variant biliary anatomy, MR cholangiopancreatography is often used for preoperative evaluation of prospective liver donors. Intravenous morphine administered prior to MR cholangiopancreatography can improve image quality by causing the sphincter of Oddi to contract, which increases pressure in and distention of the biliary and pancreatic ducts. Morphine administration may also be particularly helpful for the evaluation of patients with primary sclerosing cholangitis, malignant neoplasms such as cholangiocarcinoma, or cystic and non-organ-deforming benign pancreatic neoplasms.

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.