Étude clinique en phase 2 de la BZA2 (123IN-(2-diéthylaminoéthyl)-2-iodobenzamide) dans le diagnostic du mélanome malin oculaire et de ses métastases

PURPOSE

Iodobenzamides are reported to possess an affinity for melanoma. A first selected compound, BZA, was studied in a phase 2 clinical trial on 159 patients as an imaging agent for the detection of primary melanoma and metastases with good results. We report the results of a second phase 2 clinical trial on 40 patients with a new radiopharmaceutical BZA2 (an orthoiodinated BZA analog), which was expected to provide quality images sooner after injection and with better imaging contrast.

PATIENTS AND METHODS

Performance was evaluated in 40 patients classified with primary ocular lesions (12), suspicion of metastases of ocular or cutaneous origin (15), or with no known secondary lesion (13), and results were compared with conventional investigation techniques (ophthalmoscopy, ultrasonography, and angiography for ocular melanoma, whole-body CT scan and ultrasonography for metastases).

RESULTS

No adverse events were recorded. The overall results on a per patient basis showed a sensitivity of 78% and a specificity of 95%. The four false negatives observed were ocular lesions (three with a thickness<3mm and one achromic), but all the proven secondary lesions were imaged. Moreover, negative BZA2 scintigraphy in cases of suspicious lesions led to the correction of two diagnoses: the prostatic origin of bone metastases and the endocrine tumor origin (APUD system) of an ocular lesion.

DISCUSSION

BZA2 scintigraphy is an easy test with good tolerance. In the diagnosis of ocular primary melanoma, the sensitivity of the test is 64%, although limited by the thickness (3mm) and the pigmentation of the lesion. However, the BZA2 scintigraphy is a very useful test for the detection of melanoma metastases, with a sensitivity of 100% and a specificity of 95%.

CONCLUSION

BZA2 scintigraphy showed good tolerance in patients and it appears promising for differential diagnosis, staging, and restaging of melanoma.

Comparable uptake of thallium-201 and technetium-99m MIBI in hibernating and "maimed" myocardium

Thallium-201 and technetium-99m-MIBI uptake are comparable in "maimed" (i.e., partially viable) and hibernating myocardium. The appreciation of myocardial viability should be based not only on the presence of a regional contractility improvement, but also on the evaluation of the initial level of contractility and of tracer uptake in the concerned area.

Technetium-99m-sestamibi uptake in breast tumor and associated lymph nodes

The aim of this study was to measure the accumulation of 99mTc-sestamibi in breast tumors and their axillary lymph nodes in patients undergoing scintimammography.

METHODS

Eighteen patients who were scheduled for breast surgery underwent scintimammography with 740 MBq of 99mTc-sestamibi on the day before the operation. The next morning, reinjection with 370 MBq was performed. Immediately after the surgical procedure, the 99mTc activity of the tumor samples and, when available, the related lymph nodes was measured in a gamma counter. The samples were weighed and prepared for histological analysis. The activity of each sample was normalized to the mean activity of normal tissue samples obtained from the same patient.

RESULTS

Among the 198 samples analyzed, the relative uptake of sestamibi was increased in 111 containing normal lymph nodes (1.80+/-0.79 vs 1.00+/-0.22, p<0.05), as well as in the seven containing invaded lymph nodes (2.01+/-0.83, p<0.01) and more dramatically, in the 22 with a carcinoma (5.64+/-3.06, p<0.001). In two patients with a benign lesion, both scintigraphy and counting demonstrated increased activity in the tumor. Four patients had negative scan results despite the presence of malignant tumor and a more than fourfold increase of sestamibi concentration in two of them.

CONCLUSION

Technetium-99m-sestamibi concentrates strongly in breast carcinoma, sometimes even when the scan results appear normal, and mildly in lymph nodes, especially when invaded; it also concentrates in some benign tumors, possibly in relation to the presence of epithelial hyperplasia.

[Identification of hibernating myocardium using 99m sestamibi tomoscintigraphy at rest]

The aim of this study was to assess the value of resting 99m Tc-Sestamibi scintigraphy for the detection of hibernating myocardium in zones of contractile dysfunction. Based on a series of 25 patients, 27 segments of supposedly hibernating myocardium were identified. All these segments corresponded to left ventricular wall motion abnormalities confirmed by contrast angiography and were perfused by a stenosed coronary artery: none of these zones were infarcted. Before revascularisation, comparison of the results of ventriculography and scintigraphy showed a correlation (p < 0.001) between the severity of regional contractile dysfunction appreciated by the center line method and the degree of myocardial hypofixation of 99m Tc MIBI. Three months after revascularisation, improvement of regional wall motion, assessed by control contrast angiography, was observed in 21 of the 27 segments studied (78%). Of these 21 segments, the viability of which was confirmed, 13 had a non-transmural uptake defect and 8 were normal on pre-revascularisation scintigraphy. The 6 segments without improvement at the 3 month control, had a transmural uptake defect on scintigraphy in 67% of cases. The authors concluded that when a residual uptake defect of 99m Tc sestamibi is present, viable myocardium may also be present.

Rest technetium 99m-sestamibi tomoscintigraphy in hibernating myocardium

The myocardial uptake of rest-injected technetium 99m sestamibi on single-photon-emission computed tomographic images was assessed in 25 patients. All had an area of myocardial dysfunction that could be related to a coronary artery stenosis. None of the patients had clinical evidence of a myocardial infarction. Three months after revascularization, viability was demonstrated by contrast angiography and center-line analysis in 21 (78%) of the 27 formerly hibernating territories. Among these, none had a transmural defect, and 38% had a normal technetium 99m-sestamibi uptake. The four transmural preoperative defects were located in territories without viability. Eight of the 9 territories that were normal at scintigraphy proved to be viable postoperatively. It is concluded that as long as some residual technetium 99m-sestamibi uptake is present, viable myocardium is also present.

Reinjection as an alternative to rest imaging for detection of exercise-induced ischemia with thallium-201 emission tomography

Exercise thallium-201 single photon emission computed tomography images were compared prospectively with 4-hour redistribution images, with 4-hour reinjection images, and with images obtained at rest on a separate day in 37 patients with documented coronary artery disease. Exercise images were abnormal in 35 patients (95%). On the basis of an improvement in thallium-201 distribution between exercise and nonexercise images, overall sensitivity for the detection of coronary artery stenosis was significantly higher with reinjection at 4 hours (p < 0.05) or with a rest injection on a separate day (p < 0.05) than with redistribution imaging (84%, 83%, and 70%, respectively). Reinjection and rest injection were positive more frequently in patients with a wall-motion abnormality (76% and 80%, respectively, vs 64% at redistribution; p < 0.05 for both) or with > 90% stenosis (77% and 76%, respectively, vs 58% at redistribution; p < 0.05 for both). Among the 11 patients who had no evidence of redistribution at 4 hours, five (45%) demonstrated ischemia with reinjection and five demonstrated ischemia in the separate rest study; a total of seven patients showed improvement either at reinjection or rest. Among these 86% had a wall-motion abnormality associated with stenosis of > 90%, whereas in the other 30 patients these two conditions were observed concomitantly in only 43%. This study demonstrates that the thallium-201 4-hour postexercise reinjection technique is as sensitive as the 2-day rest/exercise method for the detection of coronary artery stenosis and provides additional information when a severe stenosis is associated with a wall-motion abnormality.

The lymphatic drainage of the human ovary in vivo investigated by isotopic lymphography before and after the menopause

The authors report 14 lymphoscintigraphies of the ovary, 8 before and 6 after the menopause. Injection of colloid labeled with technetium 99 m with elective lymphatic absorption was made into the mesovarium under laparoscopic control. Frontal and lateral images of the lymphatic drainage were made with a gamma camera 4-6 h after injection. Even in this short preliminary series, the premenopausal women showed major local and regional lymphatic circulation with drainage to the lumbo-aortic and pelvic nodes. After the menopause the lymphatic flow decreased and drainage was essentially by the aorto-lumbar nodes.

[Functional aspects of lymphatic drainage of the human ovary in vivo explored with isotopic lymphography]

Pelvic lymphoscintigraphy with 99 m Tc colloid injected directly in mesovarium during coelioscopy is able to schon that: drainage of ovaries' lymph is taken up by pelvic, paraortic or both lymph nodes, during genital activity ovarian lymph often diffuse in the other side of the pelvis with a true regional circulation.

[Evaluation of the effect of Royat thermal gas in arteriopathy of the legs using thallium-201 muscular scintigraphy]

12 patients (group II) suffering from an arteriopathy of the lower limbs, stage II, were examined by thallium 201 muscular scanning. The aim of this study was to look for a possible muscular effect of Royat thermal gas injected subcutaneously. A preliminary study was conducted at rest, and consisted of recording the initial decay curve of thallium in the thighs and the study of the muscular fixation by different segments of the limbs, including the determination of the ratios of amounts fixed by the muscular and non-muscular zones. The results were compared with those obtained in 11 healthy subjects (group I) and no significant difference was noted between the two groups at rest. On the other hand, a considerable improvement of the fixation in the legs was observed after subcutaneous injection of thermal gas. The results are discussed in relation to the clinical and paraclinical data.

Feasibility of gated single-photon emission transaxial tomography of the cardiac blood pool

A procedure for gated single-photon emission transaxial tomography of the cardiac blood pool using a commercially available rotating camera and a computer is described. During image acquisition, the end-diastolic and end-systolic frames are retained after each of the 16 angular steps of the rotation of the camera around the anterior side of the patient's chest. Complete acquisition takes 25 minutes; 10 more minutes are required for the reconstruction and processing of the sections. One set of images is oriented transaxially; the other set includes vertical sections obtained by rotation around a vertical axis passing through the center of the left ventricular cavity. Results from the planar and tomographic examinations were in good agreement for most of the 18 patients who underwent both studies, although more inferior abnormalities were detected with tomography.

A comparison between conventional scintigraphy and emission tomography with thallium-201 in the detection of myocardial infarction: concise communication

We have compared emission tomography and conventional scintigraphy with thallium-201 in a series including 15 normal subjects and 64 patients showing transmural myocardial necrosis in various locations, fully documented by clinical, electrocardiographic, and enzymatic evidence. The reconstruction was derived from 32 projection images collected around the left side of the patient's chest by a rotating scintillation camera. The conventional views and the transverse, frontal, and sagittal sections were interpreted independently by two observers. The final calculated sensitivity was 89% with conventional scintigraphy and 98% with emission tomography, and the specificity was 93% in the two cases. Thus, emission tomography provides a better sensitivity and also a better interobserver agreement than conventional scintigraphy in the detection of transmural myocardial necrosis with thallium-201.