Bone scintigraphy depicts bilateral atypical femoral stress fractures with metachronous presentation, long before a complete fracture occurs.

Atypical femoral fractures (AFF), although rare, are recognized more often during the last decade. They are located in the subtrochanteric region or the femoral shaft, may be bilateral, can evolve to complete fractures after bone overload or minimal trauma and have specific radiological features. The complete fractures have horizontal or slightly oblique configuration accompanied by a medial spike, are non-comminuted, and extend to both cortices. There is also generalized cortical thickening of femoral shaft. Newer evidence suggests that AFF are stress or insufficiency fractures, possibly associated with long-term use of bisphoshonates (BP). AFF can also occur in oncologic patients referred for bone scintigraphy and, in such a case, they should be differentiated from bone metastases. We present here a case with bilateral AFF with metachronous appearance in a female patient with a history of breast cancer and osteoporosis. The first AFF had been depicted on bone scintigraphy 3 years before a complete fracture occurred at this site, but the finding was overlooked. A second bone scan performed shortly after the fracture in order to exclude underlying bone metastases disclosed an additional unsuspected incomplete AFF in the contralateral femur, which was confirmed by radiography. In conclusion, oncologists should consider other causes of bone pain besides bone metastatic disease, and physicians interpreting whole body bone scans of oncologic patients should be aware of the entity of AFF, in order to avoid false positive results and provide early information about an impending complete AFF.

(99m)Tc sestamibi as a prognostic factor of response to first-line therapy and outcome in patients with malignant lymphoma.

INTRODUCTION: Resistance to chemotherapy poses a major problem in cancer patients. Although of multifactorial origin, some of the implicated mechanisms also interfere with (99m)Tc-MIBI uptake and retention in cancer cells. The aim of the current study was to investigate the prognostic value of baseline (99m)Tc-MIBI imaging in lymphoma. METHODS: (99m)Tc-MIBI SPECT was performed in 16 patients with Hodgkin lymphoma and 31 with non-Hodgkin lymphoma (NHL) before chemotherapy initiation. Early (20 minutes), late (120 minutes) tumor-to-background (T/B) ratios, and 2-hour (99m)Tc-MIBI washout were calculated. Follow-up data were obtained for a period of 45.5 ± 23.5 months. Study end points were response to first-line chemotherapy, lymphoma-related death (LRD), and time to disease progression. RESULTS: Of the scintigraphic indices examined, the late T/B ratio correlated best with study end points. A cutoff value of 1.8 determined by receiver operating characteristic analysis discriminated poor from good response and LRD from survival with an accuracy of 87% and 81%, respectively. Kaplan-Meier survivor functions separated by this cutoff differed significantly for both time to disease progression and LRD (P = 0.0001 and P = 0.0015). In the Cox proportional hazards model, the late T/B ratio proved to have an independent and incremental value over clinical prognostic factors (age, lymphoma type, Ann Arbor stage, lactate dehydrogenase levels) and, in NHL patients, over the international prognostic index. Patients with high international prognostic index score could be further stratified into different prognostic categories. CONCLUSION: The current study indicates that baseline (99m)Tc-MIBI SPECT can provide useful prognostic information in patients with lymphoma, particularly NHL, regarding therapy response and final outcome.

Is there a role for Nuclear Medicine in diagnosis and management of patients with primary aldosteronism?

Primary aldosteronism (PA) is the most common cause of secondary hypertension. The diagnosis of PA is of clinical importance for choosing the appropriate treatment, meaning, surgery for the unilateral disease, and inclusion of aldosterone antagonists in the antihypertensive treatment for the bilateral disease. Current diagnostic approaches showed that the prevalence of PA is much higher than previously estimated. There is still controversy regarding the true prevalence of PA in hypertensive patients. The gold standard for differentiating between unilateral and bilateral disease is the adrenal vein sampling (AVS), a method that is invasive and is performed accurately in only few dedicated centers. Non invasive methods (imaging) for discriminating the two entities are: the CT scan, MRI and iodocholesterol (NP-59) scintigraphy performed under dexamethasone suppression. But the accuracy of imaging compared to AVS is suboptimal and can result in wrong therapeutic decisions. NP-59 scintigraphy is a non-invasive functional imaging technique that reveals the adrenal cortical autonomic function and could have of incremental value over anatomical imaging. In conclusion, in previous years NP-59 scintigraphy was used infrequently, but recently with the advent of hybrid single photon emission tomography (SPET/CT) systems the interest in NP-59 scintigraphy has been renewed. Studies comparing NP-59 SPET/CT imaging with AVS are warranted in order to establish its diagnostic accuracy.

Erdheim-Chester disease: a rare syndrome with a characteristic bone scintigraphy pattern.

Erdheim-Chester disease is a rare noninherited, non-Langerhans' cell histiocytosis, with multiorgan involvement. The skeleton is frequently involved in as many as 70-80% of all cases. In nearly half of the cases, there is an involvement of other organs such as the cardiovascular system, lung, kidneys, brain, and orbits. Extra-skeletal involvement is correlated with increased morbidity and mortality. In recent years, the disease is being described with increasing frequency although fewer than 200 cases have been identified worldwide. Besides its rarity, the disease has a characteristic almost pathognomonic bone scan appearance, which in some cases facilitates diagnosis of the syndrome. Bone scans also contribute to the qualitative assessment of skeletal involvement.