Evaluation of Imaging Findings in Patients with Pretransplant and Posttransplant Tertiary Hyperparathyroidism

OBJECTIVES

Tertiary hyperparathyroidism, characterized by autonomous overproduction of parathyroid hormone, can be seen in patients with long-standing secondary hyperparathyroidism (pretransplant) or after renal transplant (posttransplant). Parathyroid scintigraphy and ultrasonography are the most commonly used imaging procedures for the preoperative localization of abnormal parathyroid glands. We aimed to evaluate imaging findings in pretransplant and posttransplant tertiary hyperparathyroidism.

MATERIALS AND METHODS

This study included 32 patients with pretransplant tertiary hyperparathyroidism and 20 patients with posttransplant tertiary hyperparathyroidism. On parathyroid scintigraphy with technetium-99m sestamibi, early-phase and latephase images were acquired. Images were evaluated for the presence and the number of active foci and the degree of uptake on the late-phase image. The existence of an autonomous gland was based on latephase retention and was scored from 0 to 2 (retention score). On ultrasonography, the criteria threshold for autonomy was the maximum length of the largest gland ≥10 mm (ultrasonography score).

RESULTS

On parathyroid scintigraphy, the most commonly observed pattern in the pretransplant group was positivity in ≥3 glands, and in the posttransplant group the most commonly observed pattern was positivity in 1 to 2 glands. In pretransplant and posttransplant groups, the criteria threshold for the presence of an autonomous parathyroid gland on parathyroid scintigraphy (grade 2 retention) was met in 26 (81%) and 9 (45%) patients and on ultrasonography in 25 (78%) and 10 (50%) patients, respectively. In the whole group of patients (n = 52), correlation existed between ultrasonography score and retention score. Glandular weight was correlated with both retention score and ultrasonography score.

CONCLUSIONS

Higher numbers of detectable glands and the presence of parathyroid autonomy were more common in the pretransplant group. This might be explained by parathyroid gland involution after transplant. The results may also suggest that factors other than autonomy are responsible for posttransplant tertiary hyperparathyroidism.

Comparison of parathyroid scintigraphy findings in pediatric and adult patients with secondary hyperparathyroidism

OBJECTIVES

Secondary hyperparathyroidism (sHPT) is a compensatory complication of chronic kidney disease. The aim of this study was to compare PS findings in pediatric and adult patients with sHPT.

METHODS

This study included 50 pediatric and 50 adult patients with sHPT. Parathyroid scintigraphy was performed with Tc-99m sestamibi. After radiopharmaceutical injection, early-phase (15 min) and late-phase (60-90 min) images were acquired. Planar images were interpreted visually for the presence / number of active foci compatible with a parathyroid lesion, the presence and degree of uptake in skeletal structures, and the degree of thyroid sestamibi uptake. Parathyroid surgery was performed in 21 pediatric and 28 adult patients.

RESULTS

Serum PTH and ALP values were significantly higher in pediatric than in adult patients ( P < 0.05 for each). In operated patients, on a lesion-based analysis, the sensitivity of PS in pediatric and adult patients were 40% and 71%, respectively. A nonlocalizing scan was observed in 24% of pediatric patients. Pediatric patients had a higher incidence of reduced thyroid sestamibi uptake (42% versus 2%). Skeletal sestamibi uptake was detected in 40% of pediatric and 30% of adult patients and the degree of uptake was higher in pediatric patients.

CONCLUSIONS

The results revealed more significant changes in the biochemical profile of pediatric compared with adult patients with sHPT. The sensitivity of PS was lower, and the likelihood of a nonlocalizing scan was higher in pediatric patients. The results may also suggest more severe skeletal findings in pediatric patients. Reduced thyroid sestamibi uptake in children needs further evaluation.

Evaluation of the effects of recipient/donor gender on early/late postoperative renal graft functions by renal scintigraphy

OBJECTIVES

We discuss the effects of recipient/donor gender on renal allograft functions using scintigraphic parameters obtained 3 days after renal transplant and 1 year after transplant.

MATERIALS AND METHODS

This retrospective study included 76 renal allograft recipients (group one, 38 males; group two, 38 females). Patients underwent scintigraphic imaging with Tc-99m DTPA on postoperative day 3 and 1 year after transplant. We used the Hilson perfusion index, maximum renal activity/background activity, ratio of renal activity at 20 minutes to renal activity at 3 minutes, time-to-peak activity, and glomerular filtration rate to measure quantitative parameters.

RESULTS

On postoperative day 3, the Hilson perfusion index, maximum renal activity/background activity, the ratio of renal activity at 20 minutes to renal activity at 3 minutes, time-to-peak activity, and glomerular filtration rate values for male/female recipients were similar (P = .65, P = .77, P = .38, P = .10, P = .99). The gender of donors was compared with the above-mentioned scintigraphic parameters of the recipients, and no statistically significant differences were found (P = .24, P = .25, P = .44, P = .29, P = .13). At 1-year follow-up, values obtained from group 1 and group 2 recipients were similar. After 1 year, chronic rejection developed in 15.7% of group 1 recipients and in 10.5% of group 2 recipients; acute rejection developed in 21% of group 1 recipients and in 23.6% of group 2 recipients. There were no statistically significant differences between the occurrence of acute rejection and the gender of recipients or donors (P = 1.00, P = .45).

CONCLUSIONS

We observed no statistically significant differences between renal graft functions and gender of the recipients/donors during the early/late posttransplant period.

Diagnostic significance of the hepatic parenchymal retention index as determined by hepatobiliary scintigraphy in liver transplant recipients

OBJECTIVES

The aim of this study was to evaluate the usefulness of the hepatic parenchymal retention index in the early diagnosis of parenchymal complications in liver transplant recipients as determined by hepatobiliary scintigraphy.

MATERIALS AND METHODS

This retrospective study reviewed 100 liver transplant recipients who had undergone orthotopic liver transplant. In all cases, hepatobiliary scintigraphy images recorded 7 to 10 days posttransplant were quantitatively reinterpreted according to hepatic parenchymal retention index. The hepatocyte extraction fraction value was also calculated. Scintigraphic findings as well as clinical, laboratory, and biopsy results were assessed.

RESULTS

Quantitative analysis showed normal hepatocyte extraction fraction value in all subjects. However, significant differences in hepatic parenchymal retention index were observed. Thus, subjects were divided into 3 groups: group 1 (n=75), normal; group 2 (n=15), severely elevated; group 3 (n=10), mildly-to-moderately elevated hepatic parenchymal retention index. Evaluation of histopathological, clinical, and laboratory findings showed normal grafts in all group 1 recipients, acute rejection in all group 2 recipients, and hepatocyte damage/intrahepatic cholestasis in all group 3 recipients.

CONCLUSIONS

Based on these findings, we determined that hepatocyte extraction fraction value was not useful, whereas hepatic parenchymal retention index was beneficial for early and accurate diagnosis of parenchymal complications in liver transplant recipients.

Comparison of standardized uptake values obtained from two- and three-dimensional modes of fluorine-18 fluorodeoxyglucose PET-CT in oncological cases

PURPOSE

We investigated the usability of standardized uptake values (SUV) obtained from both two- and three-dimensional (2D and 3D) positron-emission tomography and computed tomography (PET-CT) imaging, and compared the images obtained from these techniques in terms of image quality, lesion detectability, and the presence of artifacts.

MATERIALS AND METHODS

Image data from 100 patients, who had undergone two PET imagings obtained in 2D and 3D mode after a low dose CT, were evaluated prospectively. Subjective analysis of 2D and 3D images was performed by two readers evaluating the following criteria: overall image quality, detectability of each identified lesion, and the presence of artifacts. The lesions recognized by the readers were also analyzed quantitatively by measuring SUV values.

RESULTS

There was a significant difference between the SUVs obtained in 2D and 3D modes. Regardless if the first scan was performed in 2D or 3D mode, the values obtained from 3D imaging were significantly lower than those obtained from 2D imaging (mean SUV(max) was 10.48±7.57 for 2D, and 9.66±6.93 for 3D, P < 0.001). Visual analysis did not reveal significant differences regarding lesion detectability between two modes.

CONCLUSION

In oncological PET-CT applications, SUV values are significantly lower in 3D compared with 2D mode. Thus when serial scanning is needed to evaluate response to therapy in the same patient, the imaging modality should be taken into account and performed with the same method to avoid misinterpretation. Additionally, 3D PET-CT imaging can be used instead of 2D PET-CT due to its shorter scanning time without loss of lesion detectability.

Scintigraphic evaluation of paired renal allografts from the same cadaveric donor

The aim of this study was to compare the outcome of paired grafts in renal recipients from the same cadaveric donor using quantitative Tc-99m DTPA scintigraphy. Fifty recipients from 25 cadaveric donors were followed for a median period of 3 years. Serial Tc-99m DTPA scintigraphy was performed starting on the third posttransplant day and images evaluated quantitatively. The quantitative parameters included Hilson's perfusion index, time to maximum activity, time to half of maximum activity, the ratio of the graft activity at 20 to 3 minutes, and glomerular filtration rate. In the early postoperative period, 20 of 25 paired kidneys showed similar performances. At the end of the first year 22 of 25 pairs showed a similar evolution. At the end of the third year, the number was 21 of 25. We concluded that if cold ischemia time was prudent, there was no difference in graft outcome between the first and the second recipient of a renal transplant from the same cadaveric donor.