Patrice K. Rehm

FDG PET/MR Imaging Coregistration Helps Predict Survival in Patients with Glioblastoma and Radiologic Progression after Standard of Care Treatment

Purpose To determine the correlation between metabolic activity at fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and survival in patients with glioblastoma and suspected progression at posttherapy magnetic resonance (MR) imaging. Materials and Methods The authors retrospectively examined the relationship between metabolic activity at FDG PET in the residual lesion identified at brain MR imaging and survival time in 56 patients with glioblastoma who were treated with postoperative concurrent radiation and temozolomide therapy and who underwent FDG PET/computed tomography because of radiologic deterioration at follow-up MR imaging between 2006 and 2015. A normalized metric of metabolic activity in the residual lesion (standardized uptake value ratio [SUVr]) was calculated as the maximum standardized uptake value (SUVmax) in the tumor relative to that in healthy white matter. The primary end point of the study was survival time from PET. Patients were stratified according to SUVr. Comparisons of risk for death between subgroups were made with the log-hazard ratio of the Cox proportional hazard model. Results There was a significant association between overall survival and SUVr in the residual lesion (P = .006), and a survival benefit was observed in patients with SUVr of less than 1.7, who had a median survival time of 23.1 months (95% confidence interval [CI]: 12.7, 38.9), which was significantly longer than that in patients with an SUVr of 2.0 to less than 2.5 and those with an SUVr of at least 2.5, who had a median survival time of 10.1 (95% CI: 2.4, 15.9; P = .008) and 7.5 (95% CI: 3.9, 9.7; P < .001) months, respectively. Conclusion Patients with glioblastoma whose posttherapy MR images showed a residual lesion with high relative metabolic activity at FDG PET had a shorter survival time than did those with low activity at FDG PET.

Radioiodine (131I) accumulation in bronchogenic cyst in the setting of thyroid carcinoma remission

A 76-year-old woman had (131)I accumulation within the mediastinum in the setting of thyroid carcinoma remission. Extensive diagnostic imaging including computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound, bronchoscopy, and subsequently a needle aspiration biopsy revealed that the mass was a bronchogenic cyst. Five-year clinical and laboratory follow-up showed that the patient was free from thyroid carcinoma recurrence.

Primary osteogenic osteosarcoma of the ethmoid sinus in an adolescent: case report

Osteosarcomas of the craniofacial bones account for fewer than 10% of all osteosarcomas. Primary osteosarcomas of the nasal cavity and paranasal sinus are rare (0.5-8.1% of the osteosarcomas occur in this location). Because of the rarity of this presentation, we report a case of osteogenic osteosarcoma arising de novo from the ethmoid bone in a 13 year old male who presented with discharge from the right eye and headaches. We describe the imaging features of this rare tumor and provide a brief review of the literature.

Indium-111 Capromab Pendetide (ProstaScint®) Demonstrates Renal Cell Carcinoma and Aortocaval Nodal Metastases from Prostate Adenocarcinoma

A 62-year-old male with a history of radical prostatectomy for a Gleason 9 (4 + 5) pT3N0Mx prostate cancer presented with rising prostate-specific antigen of 9.0 ng/dl. A contrast-enhanced computerized tomography (CT) revealed an enhancing left upper pole renal mass and aortocaval lymph nodes. Indium (In)-111 Capromab Pendetide (ProstaScint ® ) single-photon emission computerized tomography-CT showed abnormal increased uptake in left renal mass and aortocaval lymph nodes with no uptake in the prostate bed or pelvic lymph nodes. He underwent left radical nephrectomy and dissection of aortocaval lymph nodes. Pathology showed renal clear cell carcinoma and metastatic prostate adenocarcinoma involving aortocaval lymph nodes. Our case demonstrates a rare combination of two different malignancies, prostate cancer and clear cell renal cell cancer, showing In-111 ProstaScint ® uptake. Though ProstaScint ® uptake in renal cell carcinoma and in metastatic aortocaval lymph nodes from prostate cancer may be seen in clinical practice, this combination has not been reported previously.

Sialadenitis following low dose I-131 diagnostic thyroid scan with Thyrogen® (recombinant human thyroid stimulating hormone--thyrotropin alfa).

Salivary dysfunction and sialadenitis are well known complications of radioiodine treatment for thyroid cancer. The parotid gland is more frequently affected and the salivary gland injury is dose related. The symptoms may develop shortly after therapeutic Iodine 131(I-131) administration or months later and progress with time. The development of unilateral parotiditis following a low dose, diagnostic I-131 scan performed following Thyrogen stimulation in a patient without prior history of sialadenitis is rare in our experience, and has not been reported in the medical literature.

Recombinant human thyrotropin use resulting in ovarian hyperstimulation: an unusual side effect.

A 43-year-old female was administered recombinant human thyrotropin-α (Thyrogen®; Genzyme Corp., Cambridge, Mass., USA) before a fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan as part of an evaluation of thyroid cancer recurrence. She was administered two doses of Thyrogen only 4 weeks before for stimulated thyroglobulin measurement. The PET/CT scan demonstrated enlarged ovaries which on subsequent conservative follow-up resolved. This transient hyperstimulated state of the ovaries was presumed to be related to Thyrogen injections received twice within a space of a month. Thyrogen is being increasingly used for raising the level of thyroid-stimulating hormone (TSH), besides thyroid hormone withdrawal for suspected recurrence of differentiated thyroid carcinoma. Ovarian hyperstimulation has been reported as an iatrogenic complication for in vitro fertilization with the presence of human chorionic gonadotropin being invariably associated. Transient gestational thyrotoxicosis has been reported to be related to promiscuous activation of the thyrotropin receptor by chorionic gonadotropin. In our case it is possible that due to the promiscuous stimulation, thyrotropin caused a follicle-stimulating hormone (FSH)-like action resulting in ovarian hyperstimulation. The reason behind this could be the shared sequence identity of the hormone-binding domains of TSH and FSH receptors, or some mutation in the FSH receptor. In conclusion, our case highlights a potential side effect of administering Thyrogen in females of the reproductive age group.

Unenhanced MRI as an Alternative to 99mTc-Labeled Dimercaptosuccinic Acid Scintigraphy in the Detection of Pediatric Renal Scarring

OBJECTIVEnThe purpose of this study was to determine whether unenhanced MRI without sedation is a feasible substitute for dimercaptosuccinic acid (DMSA) scintigraphy in the detection of renal scars in pediatric patients.nnnSUBJECTS AND METHODSnPatients scheduled for 99mTc-labeled DMSA scintigraphy for assessment of possible renal scars were recruited to undergo unenhanced MRI (free-breathing fat-suppressed T2-weighted single-shot turbo spin-echo and T1-weighted gradient-echo imaging, 13 minutes total imaging time). Scintigraphic and MRI studies were evaluated by two independent blinded specialty-based radiologists. For each imaging examination, readers identified scars in upper, middle, and lower kidney zones and rated their diagnostic confidence and the quality of each study. The scintigraphic readers consensus score opinion for the presence of scars was considered the reference standard.nnnRESULTSnDMSA scintigraphy showed scarring in 19 of the 78 (24.4%) evaluated zones and MRI in 18 of the 78 (23.1%). The two MRI readers found mean sensitivities of 94.7% and 89.5%, identical specificities of 100%, and diagnostic accuracies of 98.7% and 97.4%. Interobserver agreement was 98.7% for MRI and 92.3% for DMSA scintigraphy. The MRI readers were significantly more confident in determining the absence rather than the presence of scars (p = 0.02). MRI readers were more likely to rate study quality as excellent (84.6%) than were the scintigraphic readers (57.7%) (p = 0.024).nnnCONCLUSIONnUnenhanced MRI has excellent sensitivity, specificity, diagnostic accuracy, and interobserver agreement for detecting renal scars in older children who do not need sedation. It may serve as a substitute modality, especially when DMSA is not available.

AIDS Presenting as Granulomatous Amebic Encephalitis: PET and MR Imaging correlation

Granulomatous amebic encephalitis (GAE) is a rare and oftentimes fatal disease in immune compromised patients caused by free living amebae Acanthamoeba and Balamuthia. We report a patient in whom GAE secondary to Acanthamoeba was the initial presentation of acquired immunodeficiency syndrome in a 41‐year‐old male, and discuss the FDG positron emission tomography (PET) and magnetic resonance imaging findings that preceded the pathological diagnosis. The PET results provided complementary information when coupled with the MR brain findings. Improved understanding of the clinical and imaging findings of this deadly disease is the best hope for early diagnosis and treatment of this uncommon but deadly disease.

FDG Positron Emission Tomography and Computed Tomography Demonstration of Carcinoma Arising in an Epiphrenic Diverticulum

Esophageal carcinoma arising within an epiphrenic diverticulum is rare. We describe a case of a carcinoma in a long-standing epiphrenic diverticulum in a 62-year-old patient. Fluorine-18-2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography and Computed Tomography, and endoscopic ultrasound revealed a hypermetabolic mass within the diverticulum. A preoperative diagnosis was made via endoscopic biopsy. The patient underwent Ivor-Lewis esophagectomy. He remains well and free of recurrence 18 months after surgery.