The value of parathyroid scintigraphy on lesion detection in patients with normocalcemic primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases. Most of the patients with PHPT are asymptomatic, and only 20% of them become symptomatic with increasing levels of calcium. It has been reported that normocalcemic primary hyperparathyroidism (NPHPT) may be the incipient period of PHPT where calcium (Ca) levels are in normal range, and it may advance to overt PHPT. Early diagnosis of PHPT is important in order to prevent its complications. In this retrospective study, we aimed to evaluate the role of 99mTc-MIBI parathyroid scintigraphy on lesion detection in patients with NPHPT.

MATERIAL AND METHODS

The parathyroid scintigraphy database was reviewed retrospectively in patients with PHPT. 117 patients who underwent 99mTc-MIBI scintigraphy were recruited to the study. Serum calcium level above 10.5mg/dl was considered as hypercalcemia.

RESULTS

A total of 117 patients' (female/male:98/19) mean serum PTH levels (mean±SD) were 149±97 pg/ml in normocalcemic group (Ca:9.6±0.6mg/dL, n:38) and 189±135 pg/ml in hypercalcemic group (Ca:11.4±0.6mg/dL, n:79) (p:0.072). The sex and ages were not different between the scintigraphy positive and negative groups, but the lesion detection rates with parathyroid scintigraphy were 42% in normocalcemic group and 81% in hypercalcemic group (p<0.0001).

CONCLUSIONS

Several factors including serum Ca, the imaging protocol, existence of multiglandular disease, the size and MIBI biokinetics of the adenoma may influence lesion detectability in parathyroid scintigraphy. Although high serum Ca level is an important parameter in predicting its success, parathyroid scintigraphy remains a valuable diagnostic method even in patients with NPHPT.

Initial mini-mental state and cerebral perfusion in Alzheimer's disease

PURPOSE

The relationship between the initial mini-mental state examination (MMSE) score and cerebral perfusion was evaluated in patients with Alzheimer's disease (AD).

METHODS

In the study single photon emission computed tomography (SPECT) images of the brains of 40 AD patients were compared with the brain scans of 10 healthy controls. Each patient underwent MMSE analysis at initial evaluation as well as Tc-99 m hexamethylpropyleneamine oxine (HMPAO) brain SPECT. The patients were followed up for at least 42 months.

RESULTS

The regional cerebral blood flow (rCBF) values for patients were found to be significantly decreased for all cerebral lobes compared to the control subjects and p-values were calculated to be less than 0.001 except for occipital lobes. The most statistically significant correlation between the MMSE scores and rCBF values was determined for the left temporal lobe (p < 0.0001). A significant correlation was also found for the right temporal lobe (p < 0.005). A minimal statistically significant correlation was found for the frontal lobes and the left parietal lobe (p < 0.05).

CONCLUSIONS

The overall cerebral perfusion was decreased except in the occipital lobes in AD cases with low initial MMSE scores and there was a significant relationship between the decrease in perfusion of the temporal/frontal lobes and the left parietal lobe with the decrease in the initial MMSE scores. The most significant relationship between the decrease in the initial MMSE scores and the rCBF values was determined for the temporal lobes (especially for the left temporal lobe). It was also found that the left frontal lobe was affected from the beginning of the disease.

Association between the presence of brown adipose tissue and non-alcoholic fatty liver disease in adult humans

BACKGROUND

The presence of active brown adipose tissue (BAT) has been associated with a reduced risk of obesity in adult humans.

AIM

To examine whether the presence and activity of BAT in patients undergoing PET-CT examinations is related to the presence of fatty liver.

METHOD

We retrospectively analysed 3666 consecutive PET-CT whole-body scans performed on a total of 1832 patients who were referred for suspected malignancies. BAT-positive subjects (BAT+) were defined as subjects who showed substantial amounts of brown adipose tissue on PET-CT scans. In areas where uptake of [(18)F]FDG was identified by CT for BAT, the maximal standardised uptake values (SUVmax), defined as the maximum activity per millilitre within the region of interest divided by the injected dose in megabecquerels per gram of body weight, were determined. A ratio of mean liver attenuation to spleen attenuation <0.8 on CT scans was considered to indicate NAFLD.

RESULTS

Thirty patients of the 1832 screened individuals (2%) demonstrated brown fat uptake (BAT+ subjects). Ninety matched individuals without evidence of BAT on PET scans (BAT- subjects) were enrolled for comparison purposes. After adjustment for potential confounders, the odds ratio for having NAFLD was significantly higher for BAT- subjects (3.12, 95% confidence interval = 1.03-9.88, P < 0.05). The SUVmax for brown fat tissue was significantly correlated with the ratio of mean liver attenuation to spleen attenuation (P < 0.05).

CONCLUSION

The presence of brown adipose tissue in adulthood is independently associated with a lower likelihood of NAFLD diagnosed by CT findings.

Is anterior oblique view alone in surgical position sufficient for preoperative sentinel lymph node mapping in breast cancer? A quantitative comparative analysis with conventional views

PURPOSE

Since the anterior projection alone has several limitations in the conventional preoperative sentinel lymph node (SLN) mapping, multiple projections including anterior oblique (AO) view are preferred. There are many AO acquisition techniques described in the literature but none of them creates an image which fully reflects the surgical perspective. We aimed to compare the AO view in the surgical position with the conventional projections according to quantitative parameters.

PATIENTS AND METHODS

Sixty female breast cancer patients entered the study. Two hours after the radiotracer injection, preoperative SLN mapping at anterior, lateral and 35 degrees AO projections in surgical position was performed. For each projection, mapping success rate (MSR), the mean number of SLNs, lymphatic channel visualization rate, image contrast and distance measurements between each SLN and between the SLNs and the injection site were recorded.

RESULTS

The best MSR and image contrast for the first and the consecutive axillary SLNs were found at the AO projection. The longest distance between the injection site and the SLNs and between the two SLNs were observed at the AO views. Although the AO view gave the best results for intramammary SLNs the difference was not statistically significant from the anterior view.

CONCLUSION

The 35 degrees AO view in the surgical position was superior to the anterior and lateral projections. Therefore, the simple 4-min AO view in the surgical position may entirely reflect the surgeon's perspective and could be used safely alone in the preoperative lymphatic mapping for breast cancer patients.

Correlation of technetium-99m MIBI and thallium-201 retention in solitary cold thyroid nodules with postoperative histopathology

A comparative prospective study of technetium-99m methoxyisobutylisonitrile (MIBI) and thallium-201 with early (15 min) and delayed (90 min for MIBI, 3 h for 201Tl) imaging in the differentiation of thyroid lesions is presented. Forty patients with cold thyroid nodules visualised on 99mTc-pertechnetate scan and with dyskaryotic or atypical epithelial cells verified by fine needle aspiration biopsy underwent MIBI and 201Tl scintigraphy at 3-day intervals. Subsequent thyroidectomies were carried out in all patients. Semiquantitative analysis was performed using a lesion to non-lesion ratio on early (ER) and delayed images (DR). Additionally, a retention index (RI) was calculated using the formula RI=(DR-ER) x 100/ER. The reproducibility of the method for the early and delayed measurements was tested by analysing intra- and inter-observer variability and repeatability coefficients. Histopathologically, the nodules were found to be well-differentiated thyroid cancer in 21 patients and benign in 19 patients. There was no significant difference in the ER between malignant and benign lesions for either 201Tl or MIBI (P>0.05). However, for both agents significant differences were found between malignant and benign lesions with regard to DR (P<0.01 for 201Tl and P<0.001 for MIBI) and RI (P<0.001 for both agents). Statistical comparison of the two agents showed no significant differences (P>0.05) except with regard to DR and RI in malignant nodules (P<0.05). A receiver operating characteristic analysis was performed to determine threshold levels for the differentiation of malignant from benign nodules. Following this analysis, ER, DR and RI levels of 1.03, 1.54 and 2 for MIBI and < or =1.42, 1.24 and 5 for 201Tl were selected. Using these threshold levels, the sensitivity, specificity and accuracy of the study were 90.5%, 36.8% and 65% for ER MIBI, 61.9%, 94.7% and 77.5% for DR MIBI, 95.2%, 89.4% and 92.5% for RI MIBI, 85.7%, 47.3% and 67.5% for ER 201Tl, 80.9%, 73.6% and 77.5% for DR 201Tl, and 90.5%, 94.7% and 92.5% for RI 201Tl. In conclusion, the DR for MIBI and 201Tl is superior to the ER in detecting malignant nodules, and the RI for both MIBI and 201Tl is more valuable than the DR in differentiating malignant from benign thyroid nodules.

Tumor and infection localization in AIDS patients: Ga-67 and Tl-201 findings

Examples of Ga-67 and Tl-201 scans in AIDS patients performed at St. Vincent's Hospital and Medical Center of New York are presented. Use of these methods is the adopted approach at this institution in AIDS patients for localizing sites of tumor or infection involvement. A Ga-67 scan is the most common nuclear medicine examination performed on AIDS patients. Sequential Tl-201 and Ga-67 scans have a role in differentiating Kaposi's sarcoma from malignant lymphoma and opportunistic infections. For intracranial lesions, Tc-99m MIBI or Tl-201-201-201-201 chloride can differentiate malignant from benign inflammatory lesions.

Incidence of subclavian vein thrombosis detected during first-pass phase of radionuclide angiocardiogram

A 79-yr-old woman with asymptomatic subclavian vein thrombosis associated with transvenous pacemaker electrode and congestive heart failure is reported. The subclavian thrombosis was discovered accidentally from the first-pass radionuclide angiogram that is routinely performed with the intravenous bolus injection of the radiopharmaceutical for a gated blood-pool study. It demonstrated venous obstruction at the level of the subclavian vein and abnormal collateral circulation over the chest wall consistent with subclavian thrombosis. This case report and literature review demonstrates the importance of performing first-pass radionuclide cardioangiography routinely before multigated blood-pool studies in patients with pacemakers.

Lung-heart ratio in stress thallium myocardial perfusion imaging in patients with a history of a previous pneumonectomy

Increased TI-201 lung-heart ratio after treadmill exercise or pharmacologic stress is an indicator of left ventricular dysfunction. After pneumonectomy, it is not reliable because of increased pulmonary circulation in the remaining lung. The authors present an example of normal stress TI-201 myocardial perfusion imaging with an increased lung-heart ratio of TI-201 uptake.

Evaluation of sequential thallium and gallium scans of the chest in AIDS patients

With decreasing incidence of pneumocystis carinii pneumonia (PCP) in AIDS as a result of prophylactic regimens, there is a higher incidence of tuberculosis (TB), mycobacterium avii complex (MAC), kaposi sarcoma and malignant lymphoma. There is a need for differentiating these various pathological entities. The purpose of this study was for a retrospective evaluation of sequential thallium and gallium scans in AIDS patients for differentiating intrathoracic kaposi sarcoma from malignant lymphoma and opportunistic infections.

METHODS

A total of 181 patients had both studies completed between March 1992 and May 1994. The final diagnosis was verified only in 83 patients. Results were correlated with the CD4 counts, bronchoscopic and chest radiograph findings.

RESULTS

In patients with pulmonary kaposi sarcoma and no opportunistic infections (19 patients), a thallium-positive, gallium-negative pattern was detected in 17 patients with a sensitivity of 89%. In the presence of kaposi sarcoma plus opportunistic infections, this pattern was only detected in 7 of 19 patients (sensitivity dropped to 37%). In 45 patients with opportunistic infections and no kaposi sarcoma, only two false-positive findings were found in patients with cytomegalic virus pneumonia for a specificity of 96%. For the whole group of 83 patients, sensitivity was 63%; specificity 95%; positive predictive value 92%; accuracy 81%; and negative predictive value 75%.

CONCLUSION

A thallium-positive, gallium-negative pattern in AIDS patients has a high specificity for the diagnosis of kaposi sarcoma, however, the sensitivity dropped from 89% to 37% in the presence of opportunistic infections.

Gastric emptying patterns in Kaposi's sarcoma and gastroenteritis secondary to human immunodeficiency virus infection

The study included 11 patients with AIDS who underwent gastric emptying studies for solid food, endoscopy (esophagogastroduodenoscopy), and gastric biopsy whenever gastritis was diagnosed on endoscopy. All studies were performed within 1 week. The studies were retrospectively reviewed to analyze the changes in gastric emptying secondary to Kaposi's sarcoma (KS) with or without opportunistic infections. Two patients with KS only had rapid gastric emptying (T1/2 6.7 and 45 minutes). Two other patients with KS and opportunistic infections had normal gastric emptying (T1/2 56.7 and 70 minutes), and one patient with KS and opportunistic infections had rapid gastric emptying (T1/2 25.9 minutes). Four patients with gastritis secondary to opportunistic infections and no KS had delayed gastric emptying (T1/2 622, 92, 266.5, and 179.4 minutes). The remaining two patients had endoscopy showing gastritis not proven by biopsy, and both had rapid gastric emptying. One patient had gastric ulcer (T1/2 39 minutes), and the other had chronic active hepatitis and early cirrhosis (T1/2 15 minutes). Esophagitis was present in 6 out of 7 patients who had gastritis. Esophageal candidiasis was confirmed in three patients, and cytomegalovirus was confirmed in one patient. The findings suggest that gastroduodenal KS is associated with fast gastric emptying in patients with AIDS. However, normal gastric emptying study does not reflect normal gastric physiology in patients with AIDS.

Ewing's tumor of the mandible

A primary Ewing's tumor in the mandible is reported, and the diagnostic imaging features of this lesion are discussed. Modalities used included panoramic and plain films, computed tomography, and 99mTc-MDP scintigraphy.

Imaging of regional spread of breast cancer by internal mammary lymphoscintigraphy, CT, and MRI

Forty women with breast cancer underwent imaging by internal mammary lymphoscintigraphy (IMLS), which was correlated with the results of CT and MRI of the chest. IMLS was performed and interpreted using the previously described methods of Ege. It identified 22 instances of ipsilateral internal mammary nodal involvement, none of which corresponded to cases of abnormally enlarged (diameter greater than 1.0 cm) internal mammary nodes on CT and/or MRI. Positive IMLS was associated with axillary nodal metastases in 15 out of 22 instances. The authors conclude that IMLS provides information on regional nodal spread of breast cancer that is not available with either CT/MRI imaging or axillary biopsy.

Bone scan: a useful test for evaluating patients with low back pain

For many years it has been known that the sensitivity of bone scanning to the presence of destructive bony lesions favors its use in screening for bone metastases and osteomyelitis. More recently bone scanning has been routinely employed in evaluating benign skeletal pathology that may be the cause of low back pain. Bone scanning can play an important part in (1) identifying the cause of pain, (2) clarifying the significance of radiographic findings, and (3) evaluating the results of spinal surgery. This expansion of the role of nuclear medicine in diagnosing and managing low back pain is based in part upon novel diagnostic applications of 99mTc-methylene diphosphonate, a radiopharmaceutical that has been available for over 15 years. Equally important for this development, however, has been the recent availability of SPECT, a tomographic imaging technique that can be used to display the spine in a series of 6- to 8-mm thick sections. Slightly more than one-half of newly purchased gamma cameras are rotating systems suitable for bone SPECT studies. Thus, many community hospitals can now perform state-of-the-art bone scans for low back pain.