Pakistan Journal of Nuclear Medicine (PJNM) - Jan 2014 - Volume 04 - Issue 01

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Hepatic scintigraphy has had to take a back seat for the past 2 decades because of continuing development of anatomical imaging. Ultrasound, CT, and MRI have more or less replaced Tc-99m colloid liver-spleen scan (SCS). However, the standard SCS survives and has an important role in certain niche areas where it makes a significant clinical contribution. The standard SCS gave relatively non-specific results. Now, we are moving to more tissue-specific scintigraphic scanning e.g., somatostatin imaging. Positron Emission Tomography (PET) continues to evolve as in other areas of Nuclear Imaging. Hepatobiliary scanning with iminodiacetic acid (IDA) compounds continue to play a prominent role in certain areas. Recent developments have concentrated on new equipment and increased availability of new radionuclides. These are the subject of this review. This review also describes the value of physiological liver scintigraphy, including gallium scanning as well as dynamic flow imaging of the liver such as hepatic artery perfusion scintigraphy and tagged red cell scintigraphy.

Aims: This retrospective study aimed at determining the prevalence of biliary atresia in children presenting with persistent neonatal jaundice by technetium-99m labelled hepatoimino diacetic acid (99mTc-HIDA) scintigraphy. The results were compared with those from similar studies conducted in Pakistan, South East Asia & internationally.

Methods: The study was conducted at Nuclear Medicine Centre, Armed Forces Institute of Pathology, Rawalpindi, from June 2010 to December 2012. A total of 80 patients with persistent neonatal jaundice were included in the study with 54 males & 26 females in a ratio of about 2 to 1. Main outcome measure was demonstration of biliary atresia on technetium-99m labelled hepatoiminodiacetic acid (99mTc-HIDA) scan.

Results: Patients with a clinical diagnosis of persistent neonatal jaundice were included in the study. The mean age for males and females at presentation was 224 & 122 days respectively. Biliary atresia was diagnosed in 45 patients with 28 being male and 17 female patients respectively.

Conclusion: A significant percentage of patients (56.25%) presenting with persistent neonatal jaundice are found to have biliary atresia on scintigraphic evaluation.

Aims: Breast cancer patients often have associated metastases, caused by cancerous cells spreading through the lymphatic system to other areas of the body. As a result, it is common to remove and assess the sentinel lymph node (SLN) during the surgical removal of the tumour. To localise the SLN, an injection of 99mTc-Nanocoll is administered interstitially or intradermally which is transported to SLNs via the lymphatic system. A nuclear medicine scan is then acquired. A gamma probe is used to locate the SLN during the surgical procedure with the aid of the nuclear medicine scan images. The aim of this study was to optimise the performance of an intraoperative gamma probe system (Europrobe) having both scintillation and semiconductor probes for more accurate detection of SLN in melanoma and breast cancer patients.

Methods: The surgical Europrobe system is equipped with one scintillation CsI(Tl) detector and one semiconductor CdTe detector. Tests were performed against The National Electrical Manufacturers Association (NEMA) guidelines using an in-house developed phantom.

Results The CsI(Tl) detector has superior sensitivity and better side shielding effectiveness. The CdTe probe has better spatial and energy resolutions.

Conclusion : It is not possible for a probe to have optimum performance for all parameters, so a compromise must be reached depends on clinical and surgical preference. The Europrobe has scintillation and semiconductor probes, which allows the user to choose the most suitable probe for the intended application. The scintillation probe has high sensitivity, which is important for detection of low nodal activity, or deep-seated nodes. The semiconductor probe has superior spatial and energy resolutions, which are important for accurate localisation and scatter rejection.

Aims: To assess the impact of attenuation correction in reducing artifacts and the influence of gender and body mass on the effect of attenuation correction.

Methods: 102 patients referred for myocardial perfusion imaging (mean age: 53.24 ± 12.7) were enrolled. They all underwent stress (dynamic or pharmaceutical) and rest Tc-99m MIBI studies. Polar maps of the left ventricular cavity with 17 segments of both the noncorrected (NC) and attenuation corrected (AC) images were generated and semiquantitatively analyzed by software automatically.

Results: Segmental scores in inferior wall were significantly low (p < 0.05) particularly in male population irrespective of BMI. AC didn't do significant impact in score values in anterior wall of female population (p > 0.05). AC also generated artifactual perfusion defects in apex and apical segments (p < 0.05).

Conclusion: This study demonstrates that Attenuation correction using hybrid SPECT-CT improved average myocardial perfusion uptake in inferior regions and this technique is more beneficial to male populace.

Objective: The study was designed to observe the role of SPECT bone imaging for the detection of meniscal tears.

Methods: This study was conducted at NORI hospital Islamabad in collaboration with radiology and orthopedic departments of leading hospitals of Islamabad and Rawalpindi. Radionuclide SPECT bone imaging with Tc-99m MDP was performed on the knees of 35 patients with suspected meniscal injuries. After SPECT scanning, the patients had an MRI scan followed by arthroscopy, the gold standard for diagnosis of meniscal injuries. The Fischer's Exact Test was applied to compare the results of M.R.I with arthroscopy. p-value < 0.05 was considered as significant

Results: The results of SPECT scanning were comparable to MRI imaging in the diagnosis of meniscal tears. The sensitivity was 88% for SPECT scanning and 80% for MRI in diagnosis of meniscal tears on the basis of arthroscopy results. The specificity for MR.I and SPECT was similar for the two diagnostic moalities. However, the accuracy of SPECT scanning was found to be 80.6% compared with 74.2% for MRI for accurate for diagnosis of meniscal tears.

Conclusion: There was insignificant difference between the results of MRI and arthroscopy, and SPECT and arthroscopy (p-value 0.161 and 0.069 respectively). The overall results reveal that SPECT scanning can be very useful in diagnosis of meniscal tears.

Extrapulmonary small cell cancer (ESCC) of the prostate represents less than 1% of the prostate carcinomas and has a poor prognosis. A 63-year-old male patient presented with dysuria and nocturia and the initial ultrasonography and CT revealed a prostatic mass. On initial 18F-FDG PET-CT, the prostatic mass showed intense FDG uptake and multiple abdominal lymph nodes (LNs) with intense uptake were visualized. Prostatectomy wasdone and ESCC of prostate was diagnosed pathologically. First follow-up 18F-FDG PET-CT after chemo-radiation therapy showed near complete remission of the disease. However, second follow-up 18F-FDG PET-CT showed multiple distant metastases in lung, LNs, bone and brain.

Congenital anomalies in infancy pose diagnostic and therapeutic difficulties. Biliary atresia is a common diagnosis in children with unrelenting neonatal jaundice with conjugated hyperbilirubinaemia. The morbidity associated with this condition is compounded by the concomitant presence of complete or partial situs inversus which is a condition in which major visceral organs are reversed from their original positions.

Combination of biliary atresia with situs inversus is a challenging diagnosis to make. Equivocal ultrasonographic findings not leading to a definitive diagnosis of situs inversus, not only compound the clinical features but also lead to a delay in the correct diagnosis. Scintigraphic imaging modalities especially technetium-99m hydroxy imino diacetic acid (99mTc-HIDA) scan can play a vital role in overcoming these problems.

We report a case of 2-month-old child who presented with persistent neonatal jaundice, biliary atresia, situs inversus totalis and generalized sepsis finally leading to his death.

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