Irina Rachinsky

Bilateral idiopathic chondrolysis of the hip: a case report.

A case of bilateral idiopathic chondrolysis of the hip is presented. Chondrolysis is a process characterized by progressive necrosis of the hyaline cartilage of the acetabulum and femoral head, resulting in secondary joint space narrowing and stiffness. A 14-year-old boy was followed during a 2-year period, and the diagnostic values of the different imaging methods (radiography, magnetic resonance imaging [MRI], and bone scintigraphy) were evaluated. Scintigraphic evidence of marked periarticular uptake and premature fusion of the epiphysis of the greater trochanter was a reliable indicator of chondrolysis. Furthermore, the bone scan could precede other imaging methods (radiography and MRI) in the diagnosis of the progression of the pathologic process, status of the remodeling activity, and early involvement of an opposite joint. Given the high sensitivity of bone scans and the high specificity of radiographic and MRI examinations in the diagnosis of acute chondrolysis of the hip, all three methods are valuable and should be used as complementary diagnostic tools.

Non contrast Computerized Tomography and Dynamic Renal Scintigraphy in the Evaluation of Patients with Renal Colic: Are Both Necessary?

OBJECTIVES To determine the value of the combined use of non contrast computerized tomography (NCCT) and dynamic renal scintigraphy (DRS) in the evaluation of patients with renal colic. METHODS Forty-nine consecutive patients with renal colic were evaluated with abdominal plain films (KUB), NCCT and DRS with Tc-99m DTPA or MAG-3. NCCT results showed size and location of the urolithiasis, as well as secondary signs of obstruction. DRS was used to determine the degree of obstruction in the affected renal unit. Patients were submitted to urologic intervention or followed, decision made on the basis of clinical symptoms, degree of obstruction, size, and location of the stone. RESULTS Three patients had other etiologies than stone for their symptoms and were excluded from the study. Of the remaining 46 patients, KUB detected stones in 24 (52.2%), while NCCT in all. NCCT showed secondary signs of obstruction in 35 patients (76%). Seven patients in this group (15%) had severe hydronephrosis on NCCT and complete obstruction on DRS. Twenty-eight patients (61%) showed moderate hydronephrosis and/or peri-renal and peri-ureteral stranding on the NCCT. In this latter group, DRS diagnosed complete obstruction in 5 (18%) patients, partial obstruction in 16 (57%) and no signs of obstruction in 7 (25%) patients. Overall 34% (12/35) of the patients with secondary signs of obstruction on NCCT had complete obstruction on DRS. NCCT revealed no secondary signs of obstruction in 11 patients (24%) with partial obstruction diagnosed by DRS in one of them (9%). All 12 patients with complete obstruction on the DRS underwent early intervention. Of the 16 patients with partial obstruction of the DRS, two patients (12.5%) necessitated ureteric stent insertion. Three patients with no obstruction on the RNS underwent elective extracorporal shock wave lithotripsy (ESWL) while the rest of the patients were followed and passed their stones spontaneously. CONCLUSIONS The combination of non-enhanced helical CT and DRS assesses both anatomy and function. When NCCT shows no secondary signs of obstruction, NCCT as the sole imaging study performed may be adequate. If there are secondary signs of obstruction on NCCT, DRS can distinguish patients with different degrees of obstruction and together with the clinical course, size, and location of the lithiasis may help in selecting patients who need earlier intervention from those who may be safely observed.

Unilateral acute renal cortical necrosis correlative imaging

Bilateral acute cortical necrosis is a rare form of acute renal failure characterized by necrosis of the renal cortex and sparing of the medulla. Little information on the imaging presentation of bilateral acute renal cortical necrosis is available. The enhanced CT appearance is pathognomonic and diagnostic. The unilateral presentation of acute cortical necrosis is extremely rare, and no imaging methods have been described. The authors chose to apply scintigraphic evaluation to this unique condition complementary to CT to confirm the diagnosis. Mercaptoacetylglycine (T3) was selected to assess tubular damage, in contrast to the pure glomerular agent DTPA. Evidence of some tubular function and clear delineation of the shrunken kidney was found. Conversely, in the DTPA study the kidney was not visualized. A DMSA scan was performed for assessment of viability of the renal cortex and showed a photopenic halo around the small area of the viable cortex of the upper pole. The halo sign represents a cortical loss. The visualization of the upper pole as evidence of cortical viability as a consequence of collateral blood flow from capsular vessels was seen on angiography. Radiographic and scintigraphic correlation of this rare condition may be an effective means to confirm the diagnosis and to establish the extent of involvement. However, contrast CT remains the preferred method in the diagnosis of acute cortical necrosis.

Is osteoid osteoma an iodophilic lesion?: pathologically proved osteoid osteoma of nasal bone first seen on whole-body iodine-131 scan.

The authors present a case of pathologically proved osteoid osteoma that was visualized randomly on an I-131 whole-body scan. Search of the medical literature did not reveal any mention of radioactive iodine uptake by osteoid osteomas. Therefore, the authors concluded that this pathology must be included in the differential diagnostic list of positive findings on I-131 scans.

Diagnosis of urinary leak following abdominal total hysterectomy using renal scintigraphy.

Surgical trauma to the urinary system is a relatively rare complication following gynecological surgery. A case of urinary leak from rupture of the bladder following abdominal hysterectomy was diagnosed by Tc-99m-DTPA renal scintigraphy and confirmed by direct radio-isotopic cystography. Renal scintigraphic techniques should be very helpful in early diagnosis of surgical damage to the urinary tract.

Tubo-ovarian abscess: Tc-99m hexamethylpropylene amineoxime leukocyte scintigraphy and correlative imaging

Tc-99m hexamethylpropylene amineoxime (HMPAO) leukocytes are used widely to localize inflammatory foci and abscesses. However, the use of radiolabeled leukocytes to detect a tubo-ovarian abscess has not been reported. The authors describe two cases of tubo-ovarian abscess successfully imaged using this technique in obese women with a clinical history of prolonged fever and abdominal pain. Labeled leukocyte scintigraphy with Tc-99m HMPAO is a noninvasive, physiologic procedure with excellent imaging quality that is complementary but not competitive with anatomic imaging techniques such as US and CT. This scan is recommended as one of the steps for rapid accurate diagnosis of gynecologic pyogenic infection.

Imaging of bone to skin sinus tract from osteomyelitis of the femur by Tc-99m HMPAO leukocyte scintigraphy.

The use of bone and Tc-99m-HMPAO leukocyte scintigraphy in the diagnosis of active bone and soft tissue infection is widely accepted. The authors present an interesting case of active femoral osteomyelitis with a sinus tract leading to the skin.

False-positive Ga-67 uptake in a septic patient after severe automobile trauma.

Recent heterotopic calcifications in septic patients with multiple bone injuries after severe automobile trauma may accumulate Ga-67 and appear on the scan as areas of inflammation, causing misdiagnoses. The available literature contains only two reports of Ga-67 uptake within areas of heterotopic calcifications. In this case, post-traumatic paravertebral calcifications accumulated Ga-67 and simulated the presence of an infected hematoma. The CT and Tc-99m hexamethylpropylene amineoxime leukocyte scans were helpful in establishing an accurate diagnosis. Post-traumatic heterotopic calcifications should be considered in the differential diagnosis of a focal area of Ga-67 uptake.