Rest/Stress Intradermal Lymphoscintigraphy for the Functional Imaging of the Lymphatic System.

PURPOSE: Lymphoscintigraphy is the criterion-standard method for diagnosing lymphedema, and there is no universally standardized imaging modality. In our center, we use a new approach: rest/stress intradermal lymphoscintigraphy. METHODS: We tested 231 consecutive patients with suspected lymphedema. All patients were studied after a complex physical therapy program to reduce edema. Two doses of 99m Tc-nanocolloid were injected intradermally. Two static planar scans were taken at rest following tracer injection. Next, patients performed an isotonic muscular exercise for 2 minutes followed by postexercise scans. Subsequently, a prolonged exercise was performed for 30 to 40 minutes, after which delayed scans were taken. Abnormal patterns were distinguished into minor or major findings, according to severity. RESULTS: We identified superficial lymphatic vessels and regional lymph nodes in approximately 80% of limbs. Deep vessels were visualized in 26% of limbs. Minor findings were reported in 22.7% of limbs examined, whereas major findings were reported in 53.2% of limbs. CONCLUSION: We observed major findings including lymph stagnation, extravasation, or dermal backflow in a significantly higher percentage of limbs with secondary lymphedema than in primary. We also observed the deep lymphatic pathways in a significantly higher percentage of limbs with primary lymphedema. Intradermal radiotracer injection, combined with isotonic muscular exercise, may offer a better and faster imaging of lymphatic pathways, evaluating the effects of muscular exercise on lymphatic drainage. Based on the in-depth information of the lymphatic pathways provided by rest/stress intradermal lymphoscintigraphy, microsurgeons can obtain important functional information to perform supermicrosurgical lymphatic-venous anastomosis or vascularized lymph node transfer.

A gravity-assisted approach to the management of urinary diversion: 99mTc-MAG3 diuresis renography with F + 10(sp) method.

OBJECTIVE: Radical cystectomy with permanent urinary diversion is the gold standard treatment for invasive muscle bladder cancer. Hydronephrosis is common in these patients, but Ultrasound (US) or Computed Tomography Urography (CTU) scan are unable to discriminate obstructive from non-obstructive hydronephrosis. We used Diuresis Renography (DR) with F + 10 in seated position (sp) method in the identification of patients with a Uretero-ileal Anastomosis Stricture (UAS) who would benefit from surgical therapy. METHODS: We studied 39 asymptomatic patients, who underwent radical cystectomy and urinary diversion. Based on radiological findings (US, CTU) 44 kidneys were hydronephrotic. All patients underwent a 99mTc-MAG3 DR with F + 10(sp) method. We acquired a DR for 20 min with the patient in a seated position. Patient drank 400-500 mL of water at 5 min after tracer injection and received a 20 mg bolus of Furosemide at 10 min during dynamic acquisition. The indices Time to peak, diuretic half time, and 20 min/peak ratio have been evaluated. Retrograde pyelography confirmed UAS in all patients with DR obstructive findings. We repeated DR as follow-up in two subgroups of patients. RESULTS: DR with F + 10(sp) method showed obstructive findings in 36 out of 44 hydronephrotic kidneys. 6 patients showed non-obstructive findings. 32 patients showed obstructive findings (20 out of 32 developed UAS within 12 months after surgery). Fifteen pts underwent a surgical treatment of UAS. In 1 patient with equivocal findings, we observed an ileo-ureteral reflux. CONCLUSIONS: The DR with F + 10(sp) method in the seated position has a lower uncertain diagnostic rate, compared to the radiological findings of US or CTU, in management of bladder cancer patients with urinary diversion. The semiquantitative indices diuretic half time and 20 min/peak ratio evaluated in a condition of favorable gravity reduce uncertain responses improving interobserver concordance.

Advantages of gravity-assisted diuretic renogram: F + 10 (seated position) method.

INTRODUCTION: In 1978, O'Reilly introduced the diuretic renogram using the F + 20 method. Initially, the patient was examined in the seated position. A dose of 40 mg furosemide was injected intravenously 20 min following tracer injection and dynamic acquisition was prolonged for 15-20 min. In 1992, the guidelines suggested to study patients in the supine position to avoid risk of diuretic-induced hypotension and reduce patient movement. Unfortunately, equivocal findings were reported in 15-30% of cases. Side effects such as bladder fullness and disruption because of voiding were reported. Several methods had been proposed in the supine position, such as the well-tempered diuretic renogram F + 20, F - 15, F0 and F + 2, with different time in minute of diuretic administration in relation to tracer injection. However, as confirmed by many studies, there was no clear evidence suggesting superiority among these methods. We suggest using the diuretic renogram with the F ± 10(sp) method for the diagnosis of obstruction in adult patients with hydronephrosis and for the follow-up in patients who underwent a surgical treatment of the urinary tract. METHODS: We searched all international guidelines and articles of most influential authors published from 1978 to October 2020 on diuretic renogram. RESULTS: We selected 60 articles. DISCUSSION: F + 10(sp) method improves patient compliance avoiding bladder fullness-related problems, without need of catheterization. It allows for a more reliable quantification of the renal output, thanks to outflow indices that are favored by gravity effects.