[Examination of regional limph nodes in penile carcinoma by 99M Tc-MIBI scintigraphy]

99mTc-MIBI scintigraphy has proven utility as a clinically valuable technique for the diagnosis of various primary and recurrent malignant lesions. We report the case of a 65 year old man with penile squamous cell carcinoma and clinically questionable bilateral inguinal lymph nodes. 99mTc-MIBI scan shows increased focal uptake in both groins and in the right iliac region. The patient underwent penile amputation with bilateral lymphadenectomy. Histopathologic report revealed metastatic lymph nodes in all lymphatic basins seen with 99mTc-MIBI. We conclude that this technique has the potential of supplying clinically relevant information for the diagnosis of regional extension of patients with penile carcinoma.

Evaluation of ocular tumors with technetium-99m-MIBI: planar pinhole technique or SPECT?

OBJECTIVE

This study compares 2 imaging protocols, planar pinhole technique (PPHT) and SPECT, for evaluating ocular masses with 99mTc-MIBI.

METHODS

Sixteen patients with ocular lesions were studied. Planar images were acquired 10 min after the injection of 740 MBq 99mTc-MIBI with an LFOV camera fitted with a pinhole collimator (5.0 mm). A SPECT study was performed immediately after the planar study, using a 360 degrees orbit, 64 steps, 20 s/stop, a 128 x 128 matrix, and a low-energy high-resolution (LEHR) collimator. Twelve lesions (9.5-18.0 mm) proved to be malignant: 8 primary tumors (ocular melanoma); 3 local relapses of different tumors of the conjunctiva; and 1 ocular metastasis from breast cancer. The remaining 4 lesions (10.0-16.0 mm) were benign: 1 inflammatory lesion; 1 benign intraocular calcification; and 2 naevi.

RESULTS

SPECT images showed 11 of 12 malignant lesions (91.6%), whereas the planar technique demonstrated only 4 of the 12 lesions (33.3%). One false-positive result, the inflammatory lesion, was visualized by both techniques. The remaining benign lesions were not detected with either method.

CONCLUSION

Technetium-99m-MIBI SPECT is a sensitive technique for detecting malignant ocular tumors. SPECT imaging is a better alternative to planar imaging for ocular tumors.

Scintigraphic evaluation of malignant melanoma lesions with Tc-99m tetrofosmin

Two cases of malignant melanoma (primary and metastatic lesions) imaged with Tc-99m tetrofosmin are reported. One patient showed intense uptake in a primary skin lesion of the thorax, and the other patient had accumulation in skin, cerebellum, breast, and lymph node metastases. Like Tc-99m MIBI, Tc-99m tetrofosmin imaging may be of clinical relevance in the evaluation of suspicious skin lesions and in patients with known cutaneous malignant melanoma in the assessment of recurrent disease during follow-up evaluation.

Detection of recurrent malignant melanoma with 99mTc-MIBI scintigraphy

Initial reports suggest that 99mTc-methoxyisobutylisonitrile (MIBI) scanning may be of clinical value in staging patients with malignant melanoma. We carried out a study to evaluate the potential of this technique in the detection of recurrent disease. Whole-body 99mTC-MIBI scans were performed in 81 patients with a history of a surgically excised MM: 28 with known recurrent lesions and 53 during follow-up without evidence of disease. Images started 10 min post-injection, using a dose of 740 MBq. Diagnoses were confirmed by cytological/histological examination or at least one conventional imaging modality. Blinded interpretations of the MIBI scans were performed. Whole-body MIBI scanning correctly detected 68 (92%) of 74 metastatic lesions in the following sites: regional lymph nodes (n=23), non-regional lymph nodes (n=10), skin (n=16), brain/cerebellum (n=6), lung (n=8), bone (n=4) and breast (n=1). The technique failed to detect three subcutaneous regressive lesions (< 1 cm), one liver metastasis, one spleen metastasis and a case of multiple small lesions of the duodenal mucous membrane. In 14 patients the procedure detected previously unknown metastatic lesions. These results suggest that 99mTc-MIBI scanning is an effective imaging modality for whole-body screening of metastatic disease in malignant melanoma patients with the potential to influence treatment planning.

99Tc(m)-MIBI scanning of the thyroid gland in patients with markedly decreased pertechnetate uptake

Diffusely reduced 99Tc(m)-pertechnetate uptake is a relatively infrequent but annoying finding that impairs evaluation of the thyroid gland. We studied 32 female patients aged 19-85 years with markedly reduced pertechnetate uptake. The following causes of reduced pertechnetate uptake were recognized: treatment with iodinated pharmaceuticals (n = 15), suppression therapy with T4 (n = 11), subacute thyroiditis (n = 5) and massive tumour replacement (n = 1). 99Tc(m)-MIBI thyroid scintigraphy was performed within 24 h of the pertechnetate study. The results were correlated with neck ultrasound, serum TSH (n = 25) and surgical findings in patients who had been operated on. The technique identified the following conditions: normally sized thyroids (n = 4), diffuse goitres (n = 8), multinodular goitres (n = 17) and solitary thyroid nodules (n = 3). Moreover, substernal goitres were identified in nine patients. This condition was confirmed at surgery in seven patients. Ultrasonography was concordant in 29 of 32 patients in terms of thyroid size and structure, but failed to demonstrate substernal thyroid tissue. Our results suggest that 99Tc(m)-MIBI scintigraphy may contribute to the diagnosis of thyroid pathology and treatment planning in patients with diffusely decreased 99Tc(m)-pertechnetate uptake.

Scintigraphic detection of invasive cutaneous malignant melanoma with Tc-99m MIBI

Malignant melanoma is a relatively uncommon cancer of increasing incidence. The authors report on two cases of malignant melanoma lesions (primary and lymph node metastasis) imaged with Tc-99m MIBI. One patient revealed intense accumulation of the radiotracer in a primary skin lesion of the thorax, whereas the other patient showed increased Tc-99m MIBI uptake in a lymph node metastasis of the neck. Tc-99m MIBI imaging could be helpful in the evaluation of patients with suspicious skin lesions and in patients with known cutaneous malignant melanoma, in the investigation of lymph nodal invasion, local recurrence, and metastatic spread.

Thyroid imaging with Tc-99m MIBI in patients with solitary cold single nodules on pertechnetate imaging

Thyroid imaging was performed in 30 patients with the standard pertechnetate technique, as well as with Tc-99m MIBI using a double-phase acquisition protocol. All patients had normal thyroid function confirmed by hormone measurements and cold solitary thyroid nodules, which were evaluated by pertechnetate scanning. Tc-99m MIBI scans were reported as showing cold (N = 14), warm (N = 7), or hot (N = 9) nodules. Nodule classification was made according to fine needle aspiration biopsy findings in 20 patients. The remaining 10 proceeded to surgery and had histopathologic confirmation of their lesions. Although all cold nodules with Tc-99m MIBI were cystic, six of the warm nodules were benign lesions. No histologically proven benign nodule was hot with Tc-99m MIBI. Of the hot nodules, seven were suspicious for follicular carcinoma with fine needle aspiration biopsy (N = 3), or had histologically proven papillary carcinoma (N = 4). Delayed images in five of seven of these lesions showed nodular retention of the radiopharmaceutical. In conclusion, double-phase Tc-99m MIBI scanning of the thyroid gland could be helpful in the preoperative assessment of patients with cold solitary thyroid nodules in order to evaluate the malignancy probability of these lesions.

Tc-99m isonitrile uptake in a brain metastatic lesion. Comparison with Tc-99m DTPA using planar and SPECT imaging

Tc-99m isonitrile uptake in a metastatic brain tumor is demonstrated using planar and SPECT imaging. Comparison with Tc-99m DTPA shows a different distribution pattern and uptake intensity, suggesting a different mechanism for both tracers. It is possible that Tc-99m CPI could reflect metabolic activity of the tumor cells and might be useful to evaluate the grade of malignancy as well as the recurrence of brain tumors.

The diagnosis of liver hydatid disease in children by scintigraphy

The results of scintigraphy in 143 children with suspected hydatid disease are reported. In 65 cases, the presence of cysts as detected by scintigraphy was confirmed at surgery. In 78 cases, scintigraphy ruled out liver hydatid disease. In 52 cases with confirmed liver HC, only conventional colloid scintigraphy was carried out. A review of images is performed. In 13 patients, with a total number of 19 cysts, blood pool liver scintigraphy was done in order to investigate the degree of vascularization of the space-occupying lesion, disclosed earlier by colloid scan, and clarify its nature. A review of images is performed. The importance of the procedure is discussed reaching to the conclusion that it is advantageous to carry out colloid and blood pool liver scintigraphy prior to surgical treatment of liver hydatid disease.

Basic physiopathological patterns of perfusion and inhalation pulmonary scintigraphy

^113mIn is an excellent radiopharmaceutical for pulmonary scanning. Seven physiopathological patterns are described after the study of the results of successive perfusion and inhalation pulmonary scans—pulmonary artery obstruction, complete bronchial obstruction, partial bronchial obstruction, bronchiolar obstruction, anatomical changes in the pulmonary parenchyma, pathological pulmonary dead space, and intrapulmonary arterio-venous shunting. Pulmonary artery obstruction can be diagnosed early, precisely, and safely by this method. Pathological pulmonary dead space and intrapulmonary shunting have well-defined characteristics; the ability to demonstrate their topography and size in patients with pulmonary emphysema may lead to surgical removal of the affected regions, thus improving overall pulmonary function. The scintigraphic procedures used revealed that bronchial obstruction is associated with absent pulmonary arterial perfusion in the corresponding bronchial territory; this finding is of the utmost importance, as it may permit the diagnosis of bronchial carcinoma before any radiological changes occur.